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  • 1985-1989  (504)
  • Nuclear reactions
  • Physics
  • Recombinant DNA
  • 1
    Electronic Resource
    Electronic Resource
    DNA sequence of the metC gene and its flanking regions from Salmonella typhimurium LT2 and homology with the corresponding sequence of Escherichia coli (1989)
    Springer
    Molecular genetics and genomics 216 (1989), S. 164-169 
    Details
    ISSN: 1617-4623
    Keywords: metC ; Cystathionine-β-lyase ; Nucleotide sequence ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The DNA sequence of the Salmonella typhimurium metC gene and its flanking regions was determined. The metC gene contains an open reading frame of 1185 nucleotides encoding a polypeptide of 395 amino acids with a predicted molecular weight of 42874 daltons. S1 nuclease mapping experiments located the transcription start site of the metC gene. The nucleotide sequence and the deduced amino acid sequence for the metC genes of S. typhimurium and Escherichia coli were compared. Although there are 279 nucleotide replacements, most do not change the amino acid sequence. Nucleotide sequence analysis of the flanking regions of the S. typhimurium metC gene shows that there is an open reading frame upstream and an open reading frame downstream of the gene. The existence of the divergently transcribed upstream open reading frame (designated ORF1) was confirmed by the construction of an ORF1-lacZ fusion. The transcription start site of ORF1 was determined by S1 nuclease mapping.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00332246
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  • 2
    Electronic Resource
    Electronic Resource
    Cloning and sequence analysis of the 18 S ribosomal RNA gene of tomato and a secondary structure model for the 18 S rRNA of angiosperms (1989)
    Springer
    Molecular genetics and genomics 219 (1989), S. 17-25 
    Details
    ISSN: 1617-4623
    Keywords: Recombinant DNA ; Small subunit ; Ribosomal DNA ; Sequence comparison ; Lycopersicon esculentum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The gene of a cytoplasmic 18 S ribosomal RNA (18 S rDNA) of the dicotyledonous plant tomato (ycopersicon esculentum) cv. Rentita has been cloned, and its complete primary structure has been determined. The tomato 18 S rDNA is 1805 by long with a G+C content of 49.6%. Its sequence exhibits 94%–96% positional identity when it is colinearly aligned with the previously reported sequences of the 17–18 S rDNAs of the dicot soybean and the monocots maize and rice. A model of the secondary structure of the 18 S rRNA of angiosperms is presented and its genera-specific structural features are compared with a current eukaryotic 18 S rRNA consensus model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261152
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  • 3
    Electronic Resource
    Electronic Resource
    Stable-light-emitting Escherichia coli as a biosensor (1989)
    New York : Wiley-Blackwell
    Journal of Bioluminescence and Chemiluminescence 4 (1989), S. 551-554 
    Details
    ISSN: 0884-3996
    Keywords: Recombinant DNA ; luminescence ; luciferase gene ; Vibrio harveyi ; toxic substances ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We have studied possibilities for constructing Escherichia coli strains capable of producing stable light. Light production in E. coli is achieved by cloning the genes encoding bacterial luciferase from Vibrio harveyi. To gain the advantage of sensitive detection of light we transferred the genes under the control of a strong, regulatable promoter system.Stabilization of light produced by E. coli clones was accomplished by finding the optimal plasmid construction and growth conditions as well as suitable measuring buffers. The adjustment of the luciferase synthesis for bioluminescence measurements to a high but not harmful level gives healthy cells and stable luciferase. Cultivation at 30 °C in an uninduced state was found to be the most important factor in getting stable-light production. The overall cell metabolism being unstressed gives us the possibility of monitoring cell physiology and factors affecting it via bioluminescence reactions in vivo. To make the results easy to interpret the light emission has to be stable during a measurement period of one to several hours. In the case of the original light-producing bacteria, Vibrio and Photobacterium strains it has not thus far been possible to find conditions where light emission would be stable for several hours. Based on our findings an automated biosensor system can be developed to monitor the effects of biologically active compounds against stable-light-producing bacteria.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bio.1170040172
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  • 4
    Electronic Resource
    Electronic Resource
    Evaluation of the stability of human erythropoietin in samples for radioimmunoassay (1988)
    Springer
    Journal of molecular medicine 66 (1988), S. 241-245 
    Details
    ISSN: 1432-1440
    Keywords: Erythropoietin ; Stability ; Radioimmunoassay ; Polycythemic mouse bioassay ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Radioimmunoassays for erythropoietin are limited so far to a few specialized laboratories and this requires transport and storage of samples. We therefore tested the stability of immunoreactive erythropoietin in serum and plasma samples obtained from a uremic and a nonuremic anemic patient. No significant change in the concentration of immunoreactive erythropoietin was found in either serum or plasma samples for up to 14 days of storage. This type of stability was observed no matter whether the samples were stored at room temperature, 4° C, or −20° C. There was no difference between the estimates of erythropoietin in serum and heparinized plasma. Validity of the radioimmunoassay used in this study was demonstrated by parallelism of dilution curves of test specimens and the 2nd International Reference Preparation for erythropoietin and by a close correlation between the immunoreactivity and the bioactivity of the hormone, as assessed in the same samples by the exhypoxic polycythemic mouse bioassay. In conclusion the data obtained clearly indicate that the necessity of storage and transport of clinical samples does not limit the practicability of the radioimmunoassay for erythropoietin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01748163
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  • 5
    Electronic Resource
    Electronic Resource
    Human cytomegalovirus DNA in the temporal cortex of a schizophrenic patient (1988)
    Springer
    European archives of psychiatry and clinical neuroscience 238 (1988), S. 110-113 
    Details
    ISSN: 1433-8491
    Keywords: Schizophrenia ; Cytomegaloviruses ; Virus diseases ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using highly sensitive nucleic acids hybridization techniques, which allow the detection of 0.1–0.5 single copy gene equivalents per cell, DNA from the temporal cortex of seven definite schizophrenics, five persons with schizophrenia-like psychoses, three patients with Huntington's chorea and nine mentally normal individuals were probed with human cytomegalovirus (HCMV) DNA. A clear hybridization signal was obtained with DNA from the temporal lobe of a young schizophrenic patient, whereas DNA from the temporal cortex of controls did not hybridize to the HCMV probe. This finding is in agreement with the cytomegalovirus hypothesis of schizophrenia and hints at the possibility that viral infection of the temporal cortex may in some sporadic cases be a contributing factor to the development of schizophrenic psychoses. There is no indication, however, that infection of the central nervous system with HCMV is an aetiological factor in the great majority of schizophrenic disorders. Clearly further studies, preferably in situ hybridizations of whole brains, are needed to prove or disprove the cytomegalovirus hypothesis of schizophrenia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00452786
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  • 6
    Electronic Resource
    Electronic Resource
    A multigene family in Calothrix sp. PCC 7601 encodes phycocyanin, the major component of the cyanobacterial light-harvesting antenna (1988)
    Springer
    Molecular genetics and genomics 211 (1988), S. 296-304 
    Details
    ISSN: 1617-4623
    Keywords: Complementary chromatic adaptation ; Gene expression ; Photoregulation ; Phycobilisome ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In cyanobacteria, light is harvested by phycobilisomes which are essentially made up of chromophoric proteins called phycobiliproteins. We have characterized two gene clusters (cpcB1, cpcA1 and cpcB3, cpcA3) each encoding the two subunits of phycocyanin (βPC and αPC, respectively), one of the major phycobiliproteins in Calothrix 7601. Downstream from the gene encoding the PCα subunit in cluster 1, an open reading frame was found, cpcE1. These genes are organized in two transcriptional units, namely: cpcB3 A3 and cpcB1 A1 E1. All these genes are transcribed whatever the chromatic light received during cell growth. Consequently, although only one type of “constitutive” PC has been biochemically characterized, we have demonstrated that there are two cpc operons “constitutively” transcribed in this strain. With the previously described red light “inducible” cpcB2 A2 operon, there are three copies of the PC encoding genes in Calothrix 7601. The significance of this newly described multigene family in cyanobacteria is discussed. We have also mapped the 5′ and 3′ termini of the major transcript from the cpc1 operon. Analysis of the 5′ untranslated region of this transcript has revealed alternative secondary structures which are proposed to play a role in the regulation of the expression of this operon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330607
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  • 7
    Electronic Resource
    Electronic Resource
    Cloning, sequencing and expression of a Bacillus bacteriolytic enzyme in Escherichia coli (1988)
    Springer
    Molecular genetics and genomics 214 (1988), S. 241-248 
    Details
    ISSN: 1617-4623
    Keywords: Autolysin ; Hydrolase ; In vitro transcription and translation ; Recombinant DNA ; Transcriptional and translational signals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Several hundred bacterial isolates were screened for bacteriolytic activity by growing them on agar medium containing autoclaved, lyophilized Micrococcus lysodeikticus cells as the substrate. A Bacillus sp. producing the largest lytic zone was selected. A genomic bank of this selected bacterium was constructed in the multi-functional vector pTZ18R, with partial SauIIIA DNA fragments inserted at the SalI restriction site. Screening of 800 colonies of this bank for cell lysis gave 5 recombinants exhibiting lytic activity, as detected by analysis of extracts of sonicated Escherichia coli cells on denaturing polyacrylamide gels containing autoclaved, lyophilized M. lysodeikticus cells as the substrate. One clone (pBH2500), expressed inE. coli strain NM522, was found to code for a lytic enzyme corresponding, in molecular weight, to the 27 kDa Bacillus sp hydrolase. This clone with an insertion of 2.5 kb was then subcloned as a 929 bp EcoRI-SauIIIA fragment in pTZ18R (pBH929) and showed higher cell lytic activity. A unique open reading frame for a protein of 251 amino acids, followed by a putative terminator sequence, was found after a consensus ribosome binding site. A putative leader sequence was identified in the first 37 amino acids. One truncated subclone (pBH703), corresponding to 196 out of 251 residues from the protein N-terminal end, still possessed lytic activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00337717
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  • 8
    Electronic Resource
    Electronic Resource
    Secretion and export of IGF-1 in Escherichia coli strain JM101 (1988)
    Springer
    Molecular genetics and genomics 215 (1988), S. 19-25 
    Details
    ISSN: 1617-4623
    Keywords: IGF-1 ; Escherichia coli secretion/export ; LamB leader peptide ; Heterologous gene expression ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The processing of LamB-IGF-1 fusion protein and the export of processed IGF-1 (insulin-like growth-factor-1) into the growth medium was examined in the Escherichia coli host strain, JM101. Several strain or plasmid modifications were tried to increase export of periplasmic (Processed) IGF-1 into the growth medium of JM101. These included: (1) use of a lon null mutant strain to increase accumulation levels of unprocessed LamB-IGF-1 fusion protein; (2) use of an alternative drug resistance marker on the expression plasmid rather than beta-lactamase, thereby reducing any competition for processing of LamB-IGF-1 by signal peptidase; (3) examination of whether phage M13 gene III protein expression caused more periplasmic IGF-1 to be exported into the growth medium due to increased outer membrane permeability; and (4) examination of the effect of E. coli or yeast optimized IGF-1 codons. None of these strain or plasmid modifications caused any significant increase in export of IGF-1 into the growth medium of JM101. Solubility studies of LamB-IGF-1 and processed IGF-1 showed that virtually all of the LamB-IGF-1 and IGF-1 remaining within the cell after a 2 h induction period was insoluble. This implied that only soluble LamB-IGF-1 was processed to IGF-1 and that only soluble IGF-1 was exported into the growth medium. Taken together, the results indicated that LamB-IGF-1 and IGF-1 solubility were the limiting factors in secretion of IGF-1 into the periplasm and export of IGF-1 into the growth medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331297
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  • 9
    Electronic Resource
    Electronic Resource
    Characterization of genetic transformation in Streptococcus oralis NCTC 11427: Expression of the pneumococcal amidase in S. oralis using a new shuttle vector (1988)
    Springer
    Molecular genetics and genomics 215 (1988), S. 53-57 
    Details
    ISSN: 1617-4623
    Keywords: Competence ; Autolysins ; Choline ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have worked out conditions for the study of competence development and genetic transformation in Streptococcus oralis NCTC 11427 (type strain), a species that contains choline in the cell wall. The peak of competence was found at the early exponential phase of growth and the optimal conditions for transformation were achieved with shuttle plasmids prepared from S. pneumoniae or from Escherichia coli serving as donor DNA. Transformation with dye-bouyant density gradient purified plasmid preparations followed first-order kinetics. The pneumococcal amidase can be expressed in S. oralis harbouring a plasmid carrying the lytA gene. This enzyme lysed the cell wall of the transformed cell in the presence of detergents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331302
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  • 10
    Electronic Resource
    Electronic Resource
    Cloning and nucleotide sequence of the Salmonella typhimurium LT2 metF gene and its homology with the corresponding sequence of Escherichia coli (1988)
    Springer
    Molecular genetics and genomics 212 (1988), S. 246-251 
    Details
    ISSN: 1617-4623
    Keywords: metF ; 5,10-methylenetetrahydrofolate reductase ; Recombinant DNA ; Nucleotide sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The Salmonella typhimurium LT2 metF gene, encoding 5,10-methylenetetrahydrofolate reductase, has been cloned. Strains with multicopy plasmids carrying the metF gene overproduce the enzyme 44-fold. The nucleotide sequence of the metF gene was determined, and an open reading frame of 888 nucleotides was identified. The polypeptide deduced from the DNA sequence contains 296 amino acids and has a molecular weight of 33 135 daltons. Mung bean nuclease mapping experiments located the transcription start point and possible transcription termination region for the gene. There is a 25bp nucleotide sequence between the translation termination site and the possible transcription termination region. This region possesses a GC-rich sequence that could form a stable stem and loop structure once transcribed (ΔG=-9 kcal/mol), followed by an AT-rich sequence, both of which are characteristic of rho-independent transcription terminators. The nucleotide and deduced amino acid sequences of the S. typhimurium metF gene are compared with the corresponding sequences of the Escherichia coli metF gene. The nucleotide sequences show 85% homology. Most of the nucleotide differences found do not alter the amino acid sequences, which show 95% homology. The results also show that a change has occurred in the metF region of the S. typhimurium chromosome as compared to the E. coli chromosome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334692
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  • 11
    Electronic Resource
    Electronic Resource
    The repressor gene (c) of the Streptomyces temperate phage ϕc31: Nucleotide sequence, analysis and functional cloning (1988)
    Springer
    Molecular genetics and genomics 213 (1988), S. 269-277 
    Details
    ISSN: 1617-4623
    Keywords: Recombinant DNA ; Helix-turn-helix motifs ; In vitro transcription-translation ; Phage immunity ; Exonuclease III deletions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nucleotide sequence of the 3.4 kb SphI-G fragment that contained the repressor gene (c) of the temperate Streptomyces phage ϕc31 was determined. Analysis of this sequence revealed a large open reading frame with protein coding character and sequence changes in c gene point and deletion mutants identified this as the coding region of the repressor. Two of the mutants studied had undergone deletions of 1.1 kb and 1.4 kb that had occurred across short direct repeats of 6 bp and 11 bp, respectively. Coupled in vitro transcription-translation experiments using the cloned SphI-G fragment and Streptomyces lividans cell free extracts identified a protein product of approximately 72 kDa, in close agreement with that predicted from the nucleotide sequence. A strongly predicted helix-turn-helix motif that may be involved in DNA binding occurred towards the carboxy-terminus of the amino acid sequence. Initial attempts to clone the SphI-G fragment in Streptomyces failed; using information gained from the sequence analysis a smaller segment of this DNA fragment was cloned in S. lividans and conferred immunity to a clear plaque mutant (c1) of ϕc31.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00339591
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  • 12
    Electronic Resource
    Electronic Resource
    Cloning of two chloramphenicol acetyltransferase genes from Clostridium butyricum and their expression in Escherichia coli and Bacillus subtilis (1988)
    Springer
    Molecular genetics and genomics 214 (1988), S. 328-332 
    Details
    ISSN: 1617-4623
    Keywords: Recombinant DNA ; Chloramphenicol resistance ; cat gene ; Plasmids pC194 and pUB110 ; Inducible gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two non-homologous chloramphenicol (Cm) acetyltransferase (CAT) genes, designated catA and catB, were cloned from Clostridium butyricum type strains and characterized by restriction mapping. Both genes are efficiently expressed in Escherichia coli and Bacillus subtilis. In contrast to analogous genes from staphylococci and bacilli, gene expression is not dependent on induction by Cm. The genes are considered as chromosomal, since no association with endogenous plasmids was detectable. Southern hybridization revealed a homology between catA and the staphylococcal Cm resistance plasmid, pC194. The subunit size of the clostridial CAT enzymes expressed in E. coli was determined as 22.5 kDa (catA) and 24 kDa (catB), respectively. The C. butyricum cat genes provide potentially useful selection markers for the construction of cloning vectors from cryptic clostridial plasmids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00337731
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  • 13
    Electronic Resource
    Electronic Resource
    Coordinated regulation of type I and type III collagen production and mRNA levels of pro α1(I) and pro α2(I) collagen in cultured morphea fibroblasts (1987)
    Springer
    Archives of dermatological research 279 (1987), S. 154-160 
    Details
    ISSN: 1432-069X
    Keywords: Collagen ; Fibroblasts ; Scleroderma ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fibroblast cultures were started from affected and unaffacted skin areas of six patients with localized scleroderma in an active stage. The cell lines were studied for synthesis of procollagens and fibronectin by metabolic labeling with 3H-proline and for their contents of mRNAs for pro α1(I) and pro α2(I) collagen. For this purpose a cDNA clone for human pro α1(I) collagen mRNA was constructed. The clone was identified by restriction site mapping and hybridization to the specific mRNAs. All the scleroderma fibroblast lines produced increased amounts of type I and type III collagens and fibronectin during the early passages. The cell lines gradually reduced their elevated synthesis of collagen and fibronectin to normal or near normal levels by the tenth passage. The ratios of α1(I) and α2(I) chains and of type I and type III collagens, and the extent of type I procollagen processing, remained relatively unchanged in all the cultures. The cellular levels of type I procollagen mRNAs were increased in all the cells exhibiting an increased synthesis of collagen. The results suggest that in localized scleroderma the fibroblasts have undergone a coordinated activation of collagen synthesis at transcriptional level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00413250
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  • 14
    Electronic Resource
    Electronic Resource
    The isolation of specific genes from the basidiomycete Schizophyllum commune (1987)
    Springer
    Current genetics 12 (1987), S. 547-554 
    Details
    ISSN: 1432-0983
    Keywords: Schizophyllum commune ; Transformation ; Gene isolation ; Basidiomycetes ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have developed a routine way to isolate genes directly from the basidiomycete fungus, Schizophyllum commune. Plasmid DNA from a genomic gene library was used to isolate five specific genes by complementation of Schizophyllum mutations via transformation. The mutant strains were deficient in the ability to synthesize either adenine (ade2 and ade5), uracil (ural, encoding orotidine-5′-phosphate decarboxylase; OMPdecase), tryptophan (rpl, encoding indole-3-glycerol phosphate synthetase; IGPS) or para aminobenzoic acid (pab1). In each case, Southern analysis revealed that transformation to prototrophy was concomitant with the integration of vector sequence into the genome of the S. commune mutant. Total DNA from transformants was restricted, religated, and used to transform E. coli. Ampicillin resistant plasmids were recovered from E. coli and tested for their ability to transform the corresponding mutant of S. commune. Plasmids complementing the ade2, adeS, pabl, trpl, and ural mutations were recovered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00419565
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  • 15
    Electronic Resource
    Electronic Resource
    Fermentation of recombinant yeast producing hepatitis B surface antigen (1987)
    Springer
    Journal of industrial microbiology and biotechnology 2 (1987), S. 117-121 
    Details
    ISSN: 1476-5535
    Keywords: Fermentation ; Recombinant DNA ; Hepatitis B surface antigen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Fermentations were performed to determine parameters affecting the expression of hepatitis B surface antigen (HBsAg) in the yeastSaccharomyces cerevisiae containing the HBsAg gene. These studies emphasized inereasing both the relative abundance (HBsAg: cell mass) and total production of HBsAg. Specific activity was increased 70-fold when cells were grown in shake flasks containing nonselective rather than selective medium. The addition of adenine, ammonium sulfate or glucose to the complex medium reduced the production of antigen. Results similar to those achieved in shake flasks were obtained when the growth was performed in fermenters. A nutrient addition system was employed to increase the production of cells and HBsAg. The addition of glucose to the culture medium increased cell mass 6-fold but decreased the production of antigen. This imbalance was corrected by supplementing the glucose with complex nutrients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01569510
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  • 16
    Electronic Resource
    Electronic Resource
    Factors affecting the expression of foreign proteins inEscherichia coli (1987)
    Springer
    Journal of industrial microbiology and biotechnology 1 (1987), S. 277-282 
    Details
    ISSN: 1476-5535
    Keywords: Recombinant DNA ; Gene expression ; Genetic engineering ; Biotechnology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary A variety of factors affect the expression of foreign proteins inEscherichia coli. These include: promoter strength, efficiency of ribosome binding, stability of the foreign protein inE. coli, location of the foreign protein inE. coli, the codons used to encode the foreign protein, the metabolic state of the cell, and the location, stability and copy number of the foreign gene. This paper contains a critical review of these factors with the idea that a detailed understanding of them is the key to the development of strategies for the efficient large-scale production of foreign proteins inE. coli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01569305
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  • 17
    Electronic Resource
    Electronic Resource
    Molecular cloning of the plant plasma membrane H+-ATPase (1987)
    Springer
    Plant and soil 99 (1987), S. 185-196 
    Details
    ISSN: 1573-5036
    Keywords: Antibody ; H+-ATPase ; Membrane ; Recombinant DNA ; Transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Mineral transport across the plasma membrane of plant cells is controlled by an electrochemical gradient of protons. This gradient is generated by an ATP-consuming enzyme in the membrane known as a proton pump, or H+-ATPase. The protein has a catalytic subunit of Mr=100,000 and is a prominent band when plasma membrane proteins are analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. We generated specific rabbit polyclonal antibody against the Mr=100,000 H+-ATPase and used the antibody to screen λgtll expression vector libraries of plant DNA. Several phage clones producing immunoreactive protein, and presumably containing DNA sequences for the ATPase structural gene, were isolated and purified from a carrot cDNA library and a Arabidopsis genomic DNA library. These studies represent our first efforts at cloning the structural gene for a plant plasma membrane transport protein. Applicability of the technique to other transport protein genes and the potential for use of recombinant DNA technology in plant mineral transport research are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02370165
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  • 18
    Electronic Resource
    Electronic Resource
    The Saccharomyces cerevisiae MET3 gene: Nucleotide sequence and relationship of the 5′ non-coding region to that of MET25 (1987)
    Springer
    Molecular genetics and genomics 210 (1987), S. 307-313 
    Details
    ISSN: 1617-4623
    Keywords: Recombinant DNA ; Methionine metabolism ; Negative control ; Regulatory regions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In Saccharomyces cerevisiae, the expression of several genes implicated in methionine biosynthesis is coregulated by a specific negative control. To elucidate the molecular basis of this regulation, we have cloned two of these genes, MET3 and MET25. The sequence of MET25 has already been determined (Kerjan et al. 1986). Here, we report the nucleotide sequence of the MET3 gene along with its 5′ and 3′ flanking regions. Plasmids bearing different deletions upstream of the transcribed region of MET3 were constructed. They were introduced into yeast cells and tested for their ability to complement met3 mutations and to respond to regulation by exogenous methionine. The regulatory region was located within a 100 bp region. The sequence of this regulatory region was compared with that of MET25. A short common sequence which occurs 250–280 bp upstream of the translation initiation codon of the gene was found. This sequence is a good candidate for the cis-acting regulatory element.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00325699
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  • 19
    Electronic Resource
    Electronic Resource
    Cloning of two type II methylase genes that recognise asymmetric nucleotide sequences: FokI and HgaI (1987)
    Springer
    Molecular genetics and genomics 209 (1987), S. 570-574 
    Details
    ISSN: 1617-4623
    Keywords: Recombinant DNA ; Methylase ; Plasmid vector ; Gel electrophoresis ; Clearage map
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The modification genes of Flavobacterium okeanokoites and Haemophilus galinarum have been cloned into the vector pBR322 and expressed in Escherichia coli cells. FokI methylase gene is contained on a 3.80 kb piece of F. okeanokoites DNA. Plasmid constructs carrying this fragment of DNA are resistant to digestion by FokI restriction endonuclease but are sensitive to cleavage by HindIII, EcoRI and PstI. Unmodified λ DNA molecules, exposed in vitro to cell extracts prepared from cells habouring this plasmid, became resistant to digestion by FokI. The smallest HgaI methylase clone carries the pBR322 plasmid containing a 3.50 kb piece of H. galinarum DNA. This plasmid is resistant to digestion by HgaI. Neither the FokI nor the HgaI restriction endonuclease was detected in either clone. This is the first report of cloning modification genes whose protein products recognise asymmetric nucleotide sequences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331164
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  • 20
    Electronic Resource
    Electronic Resource
    Atoms to astronomy: Computer graphics at the Jet Propulsion Laboratory (1986)
    Springer
    The visual computer 2 (1986), S. 159-163 
    Details
    ISSN: 1432-2315
    Keywords: Education ; Animation ; Computer graphics ; Physics ; Solar system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Within the Jet Propulsion Laboratory in Pasadena, California, state of the art computer graphics animation is done in the Computer Graphics Laboratory. The topics of the animations cover many scientific disciplines. Specific features of the system developed there, both hardware and software, are discussed. The prime mover of the effort is Dr. James F. Blinn of Pasadena; his role and experiences are elaborated. Their current largest project is The Mechanical Universe; the system is used for its production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01900326
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  • 21
    Electronic Resource
    Electronic Resource
    Molecular cloning of a ribosomal protein gene from the fission yeast Schizosaccharomyces pombe (1986)
    Springer
    Current genetics 10 (1986), S. 365-370 
    Details
    ISSN: 1432-0983
    Keywords: Recombinant DNA ; Cross hybridization ; 2D-electrophoresis ; Hybrid selection translation ; Transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using the structural gene for the ribosomal protein L3 from Saccharomyces cerevisiae as a probe, we isolated a homologous fragment from genomic DNA of Schizosaccharomyces pombe. Analysis of the plasmid carrying this fragment by hybridization selection and 2D-electrophoresis revealed a 31 kDa ribosomal protein. Transformation of the vector pDB248x containing this fragment into Schizosaccharomyces pombe leads to an increased level of mRNA suggesting that we have cloned the entire and actively transcribed gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00418408
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  • 22
    Electronic Resource
    Electronic Resource
    Large mitochondrial genome and mitochondrial DNA size polymorphism in the mosquito parasite, Romanomermis culicivorax (1986)
    Springer
    Current genetics 11 (1986), S. 71-77 
    Details
    ISSN: 1432-0983
    Keywords: Mitochondrial DNA ; Population heterogeneity ; Molecular evolution ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Physical characterization of the mitochondrial genome derived from the obligate mosquito parasite, Romanomermis culicivorax has generated some surprising physical properties regarding the molecular structure of nematode mitochondrial DNA (mtDNA). Restriction enzyme analysis of this mtDNA has revealed a mitochondrial genome size of approximately 26 kb, the largest metazoan mtDNA reported to date. Isofemale lineages are monomorphic for one of three size variants, differing by 500-1,000 base pairs, present in our original field population. Cloned hybridization probes derived from a single region exhibiting a 600 by size polymorphism share strong homology with several spatially separated sites distributed about the mtDNA. This suggests that the homology is a result of repeated DNA sequence elements contained within this mitochondrial genome that contribute to mtDNA size polymorphism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00389428
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  • 23
    Electronic Resource
    Electronic Resource
    Gene cloning in Aspergillus nidulans: isolation of the isocitrate lyase gene (acuD) (1986)
    Springer
    Molecular genetics and genomics 202 (1986), S. 271-275 
    Details
    ISSN: 1617-4623
    Keywords: Aspergillus ; Isocitrate lyase ; Cloning ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An Aspergillus nidulans gene library was constructed in a high-frequency transformation vector, pDJB3, based on the Neurospora crassa pyr4 gene. This gene library was used to isolate the structural gene for isocitrate lyase (acuD) by complementation of a deficiency mutation following transformation of A. nidulans. Plasmids rescued in Escherichia coli were able to transform five different A. nidulans acuD mutants. Transformation using plasmids containing the cloned fragment resulted in integration at the acuD locus in six of nine transformants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331649
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  • 24
    Electronic Resource
    Electronic Resource
    Integration of foreign DNA following microinjection of tobacco mesophyll protoplasts (1986)
    Springer
    Molecular genetics and genomics 202 (1986), S. 179-185 
    Details
    ISSN: 1617-4623
    Keywords: Gene transfer ; Plant cell transformation ; Plant tissue culture ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary DNA from a bacterial plasmid containing the T-DNA border sequences of Agrobacterium tumefaciens was transferred into the nucleus or the cytoplasm of tobacco mesophyll protoplasts by microinjection. Following culture in hanging drops, some of these protoplasts produced calli containing the foreign DNA sequences. Evidence for the presence of the injected plasmid DNA in these calli was provided by Southern hybridization analysis. The results demonstrated that random portions of the bacterial plasmid were linked to plant DNA and that integration did not occur at the T-DNA borders present on the injected plasmid. The average number of integrated copies ranged from less than one to 1–2 per tobacco genome. The frequency of integration averaged 14% with intranuclear injections compared to 6% with cytoplasmic injections. With further refinement, the use of microinjection may allow the introduction of many different types of genetic elements into plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331634
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  • 25
    Electronic Resource
    Electronic Resource
    In vivo cloning of DNA into multicopy cosmids by mini-Mu-cosduction (1986)
    Springer
    Molecular genetics and genomics 205 (1986), S. 546-549 
    Details
    ISSN: 1617-4623
    Keywords: Transposition ; Genomic libraries ; Recombinant DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A general in vivo procedure for cloning Escherichia coli genes into cosmids has been developed. The method we describe here uses a deleted Mu phage (a mini-Mu) to transpose E. coli genes into cosmids during mini-Mu replication. The resulting cosmids clones are packaged in-vivo into λ phage particles. Plasmids carrying a particular DNA sequence can be selectively recovered after infection of a new host with the in vivo constructed genomic cosmid library. This system was used succesfully to clone several E. coli genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00338096
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  • 26
    Electronic Resource
    Electronic Resource
    Quantum yield for poly(methyl methacrylate) chain scission by 214-229 nm wavelength light (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1749-1758 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The quantum yield for poly(methyl methacrylate)chain scission by ultraviolet light in the 214-229 nm wavelength region was found to be φd = 0.03 scissions per absorbed photon. Samples were 1.65-μm films spun cast on silicon wafers and irradiated under flowing nitrogen by a cadmium vapor lamp. Gel permeation chromatography was used for molecular weight determination. Heating (postbaking) the irradiated films at 150°C for one hour under reduced-pressure flowing nitrogen increased the observed scissions per absorbed photon to 0.04. Glass transition temperatures by DSC are well-represented by Tg (K) = 393.3 - 2.0 × 105/Mn for the postbaked samples (139,000 〉 Mn 〉 6500).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230902
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  • 27
    Electronic Resource
    Electronic Resource
    Evidence for sorption-desorption phenomena during thermal cycling in highly hydrated perfluorinated membranes (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2009-2020 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Perfluorinated ionomer membranes can absorb large amounts of water. DSC experiments show the existence of exothermic or endothermic peaks for water contents larger than 8 wt % at room temperature in Nafion 1200 EW in the acid form. Changes in the number of mobile protons versus temperature have been measured by NMR spectroscopy. A desorption process with an activation energy of 6 kcal/mol is proposed during the sample cooling. Such an explanation quantitatively explains both the DSC and NMR results and is also consistent with the other results obtained from mechanical experiments, low-temperature sorption isotherms, and ESR spectroscopy.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180231003
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  • 28
    Electronic Resource
    Electronic Resource
    Conformational analysis of substituted polyacetylenes (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2021-2030 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A conformational analysis of isolated chains of polymethylacetylene (PMA), polypentylacetylene (PPA), and poly(t-butylacetylene) (PTA) was carried out taking into account interactions between nonbonded atoms and torsional potentials. It was found that the trans configuration of all three polymers is more stable than the cis configuration, the difference in potential energy between the trans and the cis isomers however being very small for PTA, leading to the possibility of observing a trans→ cis isomerization in some solvents. The calculations show that the substituted polyacetylenes are not found in a planar conformation, the larger deviations from planarity being found with the bulkier substituents: PTA 〉 PPA 〉 PMA. A correlation could be established between the UV absorption limit of the samples and the minimum torsional angle of the potential-energy functions. This relation predicts that the absorption limit is shifted to long wavelengths on increasing the planarity of the molecule. Moreover, UV spectra could be calculated from the potential-energy functions, and it is shown that the potential-energy functions of other substituted polyacetylenes can be calculated from their experimental UV spectra.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180231004
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  • 29
    Electronic Resource
    Electronic Resource
    Determination of the geometric structure of three substituted polyacetylenes: Polymethylacetylene, polypentylacetylene, and poly(tbutylacetylene) (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2031-2041 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The geometric structure of polymethylacetylene (PMA), polypentylacetylene (PPA), and poly(t-butylacetylene) (PTA) was investigated by 1H NMR, 13C NMR, and IR spectroscopies. It was shown that both NMR techniques can be used to determine the trans isomer content of PPA and PTA, whereas the 1H NMR and IR methods can be used for PMA. A calibration curve was constructed by using the 965- and 720-cm-1 bands of the IR spectrum of PPA, and could be used in future work for the same purpose if the samples had molecular weights similar to that of the one used in this study. The isomerization kinetics of PTA was investigated and cis→ trans activation energies of 88 and 121 kJ/mol were calculated in solution and in the solid state, respectively. Heat treatment of the PMA and PPA samples always leads to a cis→ trans isomerization with a 100% trans content under extreme conditions. Moreover, a cis→ trans isomerization of PTA was induced in CCl4, CDCl3, toluene, and benzene, but a trans→ cis isomerization was induced in decalin. The reversible isomerization of PTA covered a trans isomer concentration ranging form 25 to 60%.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180231005
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  • 30
    Electronic Resource
    Electronic Resource
    Spectroscopic study of α- and β-phase isotactic polypropylene and of atactic polypropylene in solution (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2043-2057 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Raman spectroscopy is used to investigate the conformation and packing of isotactic crystalline α-phase polypropylene compared with lower-order β-phase isotactic polypropylene and to study the solution behavior of atactic polypropylene. The high-frequency region of the spectrum is analyzed in light of a normal-mode calculation that takes into account the methyl-group vibrations. This region is sensitive to both chain conformation and packing, and because of the high intensity of the methyl and methylene high-frequency stretching modes, it can be used to probe small changes in intermolecular or intramolecular order. Differences in the thermal behavior between the two solid isotactic polypropylene samples are explained interms of packing defects which exist in the β-phase form. In the solution study, we demonstrate that, for molecules in which bands sensitive to intermolecular interactions exist, as is the case of the methyl and methylene vibrations of polypropylene, spectroscopic techniques can be used to estimate the minimum overlap concentration.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180231006
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  • 31
    Electronic Resource
    Electronic Resource
    Analysis of stress-induced crystallization in high-cis-1,4-polybutadiene (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2109-2118 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Stress-induced crystallization of a crosslinked polybutadiene with a high 1,4-cis content is investigated, at room temperature. The change in the fraction of crystallinity with deformation is evaluated by two different methods. The first is based on simultaneous measurement of birefringence and stress. The second is based on calorimetric analysis. The data on crystallinity obtained by these two methods are in good agreement in the range of low deformations, while, in the range of higher deformation (λ 〉 5), the degree of crystallinity obtained by calorimetry is higher than that obtained by the optical method. Qualitative information on the crystallization was also obtained by optical analysis of the hysteresis behavior. The hysteresis data show the presence of ordering phenomena at deformations at which there seems to be no crystallinity according to both quantitative methods.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180231009
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  • 32
    Electronic Resource
    Electronic Resource
    Coherent elastic scattering of a reptating chain in a melt during transient relaxation (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 833-844 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We calculate the elastic scattering of a long chain in a polymer melt during the process of relaxation after a sudden deformation, i.e., the return to equilibrium with time, while the deformed shape is maintained. The scattering thus depends on the duration t of the relaxation, as well as on the scattering vector, and is a physical quantity characteristic of the dynamics of long chains. The reptation model of de Gennes is used as developed for deformed melts by Doi and Edwards: the chain is confined by other chains in a tube, from which disengagement by the ends is the only way of renewing its configuration. The tube diameter is taken as a parameter. We give both an analytic form and numerical evaluations. On comparison with calculations based on the Rouse model, in which the chain is assumed to be free in a viscous medium, it is seen that the experimental data (given elsewhere) should enable one to distinguish between the two models.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230501
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  • 33
    Electronic Resource
    Electronic Resource
    Spectroscopic characterization of acetylene-terminated sulfone resin (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 845-859 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fourier-transform infrared spectroscopy was used to characterize the thermal polymerization of the acetylene-terminated (AT) resin, bis[4-(3-ethynylphenoxy)phenyl]sulfone. Spectral processing techniques (including the method of factor analysis) were utilized in the analysis of the infrared data. The degree of cure was quantitatively monitored as the resin was thermally polymerized. Factor analysis indicated that only one reaction product is spectroscopically distinguishable. Further band analysis indicated the formation of predominantly trans conjugated polyene structures. No evidence for cyclotrimerization was found.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230502
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  • 34
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    Electronic Resource
    Quantitative aspects of internal reflection spectroscopy: Polymer surface composition measurementThis paper was presented in part at the FACSS XI meeting, Philadelphia, Pennsylvania, 1984. (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 861-871 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The use of band-ratioing techniques in internal reflection spectroscopy (IRS) for a wide variety of polymer surface composition and orientation measurements is discussed. It is shown that quantitative data can be obtained under a wide range of experimental conditions. The effects of variations in sample contact, internal reflection element, and angle of incidence are considered in detail. The applicability and limitations of calibration procedures for the determination of surface composition under various experimental conditions are considered. The requirements for obtaining quantitative results by IRS are shown to be far more lenient than is typically assumed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230503
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  • 35
    Electronic Resource
    Electronic Resource
    Percolation and effective-medium theories for perfluorinated ionomers and polymer composites (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 933-953 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Percolation and effective-medium theories are applied to model the transport and elastic properties of perfluorinated ionomers. The composite nature of these polymers is emphasized. The effective-medium theory is generalized to track continuously the evolution from lamellar to fibrillar morphology. The predicted dramatic difference in ion selectivity between lamellar and spherical morphology is verified quantitatively in perfluorinated ionomer blends. The limitations and potential improvements of the effective-medium theory and its relationship to percolation theory are discussed. Applications of these theories to other multiphase polymer systems are also discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230508
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  • 36
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    Electronic Resource
    Effect of molecular weight on the refractive index increments of polystyrene, poly(ethylene glycol), poly(propylene glycol), and poly(dichlorophenylene oxide) in solution (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 925-931 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The variation of refractive index increments with molecular weight has been studied using solutions of polystyrene (2.2 × 103 〈 Mw 〈 1.8 × 106), poly(ethylene glycol) (1.0 × 103 〈 Mw 〈 2.0 × 104), and poly(dichlorophenylene oxide) (3.3 × 103 〈 Mw 〈 4.8 × 105) in toluene and poly(propylene glycol) (1.2 × 103 〈 Mw 〈 4.0 × 103) in benzene. The refractive index increments of polyglycols containing aliphatic ether moieties are negative in these solvents. However, poly(dichlorophenylene oxide) polymers, which contain aromatic ether moieties, give positive values. Linear and branched halogenated poly(phenylene oxide)s show an asymptotic approach of the refractive index increment to the same limiting value, but the approach is more rapid for the branched polymer.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230507
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  • 37
    Electronic Resource
    Electronic Resource
    Influence of the interphase on block copolymer thermodynamics: Extension of the leary model (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1001-1029 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Leary-Williams model for the microphase thermodynamics of triblock ABA copolymers has been modified to accommodate deviations from homogeneous random-coil configurations in the B-chain dimensions as well as in those of the A chains, and has also been extended to cover the case of diblock AB copolymers. Only planar morphology is considered, but qualitative conclusions reported herein are expected to hold for other morphologies as well. The focus is on interphase thickness ΔT, with predictions made also for separation temperature Ts and planar repeat distance D. Results are presented as systematic functions of copolymer composition (0 ≤ φA ≤ 1), total molar volume (25,000 ≤ Ṽ ≤ 4 × 106 cm3/g mol), block architecture (AB vs. ABA), temperature (298, 373 K), and for five different interphase composition profiles. In most cases, A represents a polystyrene block and B a butadiene block in these calculations. Predictions for ΔT increase with temperature and depend on architecture, profile, and Ṽ; comparisons with data are close, in the range 15-30Å. It is shown that Ts depends strongly on profile choice and φA, reaching a maximum in the φA midrange but always with φA 〉 0.5. The major parameter influencing D (at constant Ṽ) is architecture, with D(SB) ≈ 2D(SBS), and D(Ṽ) varies from D ∝ Ṽ0.75 at low Ṽ to D ∝ Ṽ0.5 at high Ṽ.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230512
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  • 38
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    Electronic Resource
    Morphological studies of liquid-crystalline cellulose derivatives. I. Liquid-crystalline characteristics of hydroxypropyl cellulose in 2-hydroxyethyl methacrylate solutions and in polymer composites prepared by bulk polymerization (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1043-1052 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The formation of liquid-crystalline structure in hydroxypropyl cellulose (HPC) in the solvent 2-hydroxyethyl methacrylate (HEMA) is described. In addition, an attempt is made to preserve the ordered structure of HPC in a composite by polymerizing the solvent. Optical evidence, including refractive index, absorption spectra, polarized-light microscopy, and x-ray diffraction, indicates that HPC-HEMA solutions exhibit the cholesteric nature of the mesophase over limited concentration and temperature ranges. The polymer composite (HPC-PHEMA) prepared from the liquid-crystalline solution by polymerization of HEMA is endowed with anisotropic organization reflecting liquid-crystalline character. Detailed morphological observations of the composite by electron microscopy show many round particles composed of parallel-stacked, disklike lamellae, and aggregate bodies developed by coalescence of neighboring particles.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230514
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  • 39
    Electronic Resource
    Electronic Resource
    Time dependence of mechanical and transport properties of drawn and annealed linear polyethylene (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1217-1234 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Linear polyethylene both as drawn, or drawn and subsequently annealed with free ends, changes its length, density, crystallinity, elastic modulus, sorption, and diffusivity as the sample stands completely unrestrained at room temperature. Most of these changes occur during the first few hours. But they are important on a molecular scale since they suggest strongly that drawn, and drawn and annealed samples are far from equilibrium. As a consequence of the tendency of each mobile tie molecule in the amorphous conformation to retract and to crystallize, the specimen approaches but does not reach complete equilibrium. The transient seems to be caused by slow crystallization of tie molecules which creates crystalline bridges across the amorphous layers.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230613
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  • 40
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    Electronic Resource
    Random-coil configurations of aromatic polyesters: Birefringence of poly(triethylene glycol terephthalate) networks in elongation (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1235-1245 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hydroxyl-terminatd poly(triethylene glycol terephthalate) was crosslinked with an aromatic triisocyanate. Birefringence-stress-strain experiments, performed on the networks at 70°C, showed an anomalous increase in the modulus and a downturn in the birefringence-strain isotherms at high elongations. These results suggest that crystallinity is not responsible for the non-Gaussian behavior of the chains at high extension. The same kind of experiments were performed over the range 20-70°C. Values of the optical configuration parameter Δa of the order of 13.3 × 10-24 cm3 with negligible temperature coefficient were found for these networks. The quantities Δa and d In Δa/dT were calculated by means of the rotational isomeric state model. Better agreement between the theoretical and experimental values of these parameters was found for poly(triethylene glycol terephthalate) than for poly(diethylene glycol terephthalate). Since the polarities of the two chains are similar, intermolecular interactions involving terephthaloyl residues may be responsible for the discrepancies observed between theory and experiment for Δa in aromatic polyesters.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230614
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    Dilute-solution properties of trans-1,4-polyisoprene (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1255-1262 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Trans-1,4-polyisoprene was fractionated by both fractional precipitation and preparative gel permeation chromatography to obtain possibly sharp fractions of narrow molecular weight distribution. Selected fractions were characterized by light scattering, viscosity, and gel permeation chromatography. Necessary corrections for molecular heterogeneity were applied. Some of the characteristic relations between [η] and Mw are [η] = 1.81 × 10-4 Mw0.722 in benzene at 30°C, [η] = 1.38 × 10-4 Mw0.711 in n-hexane at 30°C, which are found to be in good agreement with literature data when corrected for molecular heterogeneity.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230616
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  • 42
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    Picosecond relaxations in hydrated polyamide-6 observed by millimeter-wave spectroscopy (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1247-1254 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Absorption measurements at millimeter-wave frequencies (50-151 GHz) are reported for dried and hydrated polyamide-6. The measurements were extended over the temperature range from liquid helium to room temperature using the oversized-cavity technique. For dried polyamide-6 (water content ≤ 0.5% w/w), a nearly linear increase with frequency and an exponential increase with temperature of the absorption coefficient is found between 50 and 300 K. This frequency and temperature dependence is described by relaxation processes in asymmetric double-well potentials. The observed relaxation times are on a picosecond time scale, thus suggesting an assignment to the NH…OC hydrogen bonds and the adjacent peptide unit (O=C—N—H). Hydration results in an increase of the absorption over the whole temperature and frequency range. This is attributed to the fact that the water of hydration is adsorbed in the neighborhood of the hydrogen bonds and changes their dynamical properties. This interpretation is supported by IR-spectroscopic measurements of the shift of amide I and amide II after hydration.
    Additional Material: 6 Ill.
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    An experimental test of the relationship between creep and dynamic linear viscoelastic data (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1263-1265 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230617
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  • 44
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    Effects of a magnetic field applied during the curing of a polymer loaded with magnetic filler (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1267-1269 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230618
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  • 45
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    Dilute solutions of poly(vinyl alcohol) derived from vinyl trifluoroacetate (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1703-1712 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dilute-solution behavior of poly(vinyl alcohol) (PVAVTFA), derived from vinyl trifluoroacetate, in water-dimethylsulfoxide (DMSO) mixtures was investigated. With solvent mixtures ranging from 10 to 20 vol % DMSO, the relation between the reduced viscosity ηsp/C and the polymer concentration C was linear for polymer concentrations above 0.2 g/dL, whereas in solutions in mixed solvents of other compositions the dependence was linear for polymer concentrations above 0.1 g/dL. The relation between the intrinsic viscosity [η] obtained for aqueous solutions of PVAVTFA and the molecular weight M estimated from viscosity measurements in solutions of poly(vinyl acetate) (PVAVTFA), obtained by acetylation of PVAVTFA, was given by [η]30°Cwater = 7.34 × 10-4 M0.63. The value of [η] was greatest for the solvent mixture with 10 vol % DMSO and smallest for about 50 vol % DMSO, and Huggins constants k were smallest and greatest for these two cases, respectively. The turbidity of the solutions of low-molecular-weight PVAVTFA, was higher than that of high-molecular-weight PVAVTFA up to 30 vol % DMSO, and the reverse relation held for 40-70 vol % DMSO.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230821
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    Polydimethylsiloxane-polyurethane elastomers: Synthesis and properties of segmented copolymers and related zwitterionomers (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2319-2338 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of polyurethane block polymers based on hydroxybutyl-terminated polydimethyl-siloxane soft segments of molecular weight 2000 were synthesized. The hard segments consisted of 4,4′-methylenediphenylene diisocyanate (MDI) which was chain extended with either 1,4-butanediol (BD) or N-methyldiethanolamine (MDEA). The MDEA-extended materials were ionized by using 1,3-propane sultone. The weight fraction of hard segments was in the range 0.13-0.39. The morphology and properties of these polyurethane elastomers were studied by a variety of techniques. All of these short-segment block copolymers showed nearly complete phase separation. The zwitterionomer materials exhibited ionic aggregation within the hard domains. Hard-segment crystallinity or ionic aggregation did not affect the morphology. Hard-domain cohesion was found to be a more important factor than hard-domain volume fraction in determining the tensile and viscoelastic properties of these elastomers.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231106
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  • 47
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    Polyethylene fiber formation in tubular flow. II. Discussion of precursor formation and nucleation time analysis (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2359-2368 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This is a continuation of the preceeding paper, Part I, and presents a discussion of the nature of the precursor structure formation process observed in the flow-induced crystallization experiments described in I. A discussion of stress-induced crystallization theory as applied to these experiments is also given and a first-order analysis of crystal nucleation rates is presented. Conclusions regarding the nature of flow-induced crystallization and our current ability to quantitatively model the overall process are also presented.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231108
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    Polyethylene fiber formation in tubular flow. I. Observations of growth pattern and fiber properties (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2339-2358 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The process of seeded growth of fibrillar polyethylene crystals has been studied in a tubular flow geometry for 0.01-wt % solutions of a high-molecular-weight polyethylene in xylene. The transformation sequence has been followed visually by using polarized-light illumination in conjunction with a video camera. Data are presented to show that transformation is initiated by the formation of a concentrated, unoriented, amorphous precursor fiber within which oriented birefringent crystals subsequently grow in consequence of the stresses transmitted by the flowing solution. Time constants for the precursor formation, birefringence initiation, and completion of birefringence were measured as functions of temperature and flow rate over a range of growth conditions. Wide-angle x-ray diffraction, overall birefringence, and optical hot-stage melting data were also obtained on the grown fibers. The net result of these observations is to conclude that fibrillar crystal growth during flow is always preceded by the formation of a liquidlike phase transformation which produces the concentrated, unoriented precursor. Subsequent orientation is in consequence of stress-induced crystallization with overall fiber orientation showing an increase with solution flow rate at a fixed temperature and a decrease with temperature at a fixed flow rate. At higher temperatures and lower flow rates, birefringence develops in an oscillatory fashion, indicating a remelting process possibly due to slippage of trapped chain entanglements formed by flow. A discussion is given of the implications of these observations for the understanding of flow-induced structure development, phase transformation, and oriented crystallization; this is expanded upon in a companion paper, Part II.
    Additional Material: 10 Ill.
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    Structure of iodide ion arrays in iodinated nylon 6 and the chain orientation induced by iodine in nylon 6 filmsPresented at the XIII Congress and General Assembly of the International Union of Crystallography, August 1984, Hamburg, Federal Republic of Germany. (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2369-2376 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two species of iodide ions (I3- and I5-) are found in iodine - nylon 6 complexes. Orientation of I5- arrays (most likely I2/I3- complex) along the polymer chain and I3- ions perpendicular to the chain axis in uniaxially drawn films and in films with planar orientation suggests that there is and intrinsic relation between the direction of iodide ion arrays and nylon 6 chains. When an unoriented film of nylon 6 in the amorphous or the α crystalline form is treated with an aqueous solution of iodine - potassium iodide, the I3- species in the resulting iodine - nylon complex lie in planes parallel to the surface of the film, and I2/I3- units are oriented normal to the surface of the film. The γ form obtained by desorbing the iodine from this complex shows considerable uniaxial rientation with the nylon chains oriented perpendicular to the plane of the film; this orientation is maintained during the γ to α transition. It is proposed that the iodine-induced orientation of the nylon 6 chains is due to the nucleating effects of the iodide ion species as the iodine diffuses unidirectionally into the film.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231109
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  • 50
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    Estimation of the equilibrium modulus of rubber networks by nonlinear regression analysis (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2377-2385 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A nonlinear regression analysis is presented to estimate the equilibrium modulus of relaxing rubber networks from G'(ω) or G(t) data. Various semiempirical curve-fitting equations are tested with two-function minimization algorithms.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231110
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    Tube relaxation: A quantitative molecular model for the viscoelastic plateau of entangled polymeric mediaThis paper is dedicated to Dr. Pierre Thirion on the occasion of his retirement. (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2423-2442 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The relaxation of an entangled polymeric medium in the viscoelastic plateau is investigated theoretically by using the slip-link representation of topological constraints. In addition to the chain retraction process introduced by Daoudi and investigated theoretically by Doi, we show that two processes contribute significantly to the relaxation: The first, “equilibration across slip-links,” is a longitudinal reequilibration between parts of the chain which have been differently extended or compressed, depending on their initial orientation relatively to the strain tensor. The second, “tube relaxation,” is a mean-field representation of the loss of topological constraints on one chain due to the retraction of the others. Closed analytical expressions for the stress accounting for these three processes are derived and compared with previous theories: the relaxation should be much more progressive than previously predicted, and the terminal time for retraction is reduced significantly by tube relaxation.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231202
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    Evaluation of theories for diffusion in polymer-solvent systems (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2469-2475 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method is proposed for examining differences in the predictive capabilities of three versions of the free-volume theory of polymer - solvent diffusion using only a small amount of diffusivity data. The utility of the method is illustrated using a limited diffusivity data set for the methanol-poly(vinyl acetate) system.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231205
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  • 53
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    Temperature dependence of the crystal structures of nylon 11 (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2477-2482 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Careful examination of x-ray diffraction patterns from melt-crystallized nylon 11 films show significant discrepancies with the proposed α-form structure. These discrepancies do not disappear after the samples have been annealed. The temperature dependence of the d spacings of the two strongest peaks show further evidence that the melt-crystallized and solution-cast films (α form) possess different crystal structures. These results suggest a different crystal structure for the melt-crystallized films; this would help explain the rather low piezoelectric response of these films and also the failure to observe a rapid decrease in polarization at the transition temperature.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231206
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  • 54
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    Kinetics of wetting of a glass surface by molten polyethylene: An empirical approach (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2499-2504 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The spreading kinetics of molten polyethylene was studied on a flat type A glass surface. Empirical equations are known in the literature which fit the experimental data only at short times. We present a relationship between the surface free energy and the shape of the melt drop interpreted by the θ contact angle. Relating the experimental θ values obtained at different times with the surface free energy (F), we obtain curves F,t. Using isothermal data at 150°C, we could fit them with a linear relationship between In (F-F∞)/(F0-F∞) and In t/t0, where o and ∞ are related to initial and equilibrium conditions.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231208
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    The influence of morphology on the dielectric and dynamic mechanical behavior of a linear low-density polyethylene (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2483-2498 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dielectric and viscoelastic relaxation behavior of linear low-density polyethylene has been investigated. All three usual relaxation regions occur; however, the α process is more dominant than in conventional low-density polyethylene made dielectrically active through the introduction of carbonyl groups. The observed behavior is very sensitive to orientation and morphology. There are significant differences between oriented samples (stretching or extrusion) and a single-crystal texture specimen. Effects are caused by dipolar orientation and dipolar immobilization, the relative importance of each effect varying with specimen preparation. Active dipolar groups are not carbonyls, or any common organic species, but appear to be due to chain ends having residual dipoles caused by the catalyst used in synthesis.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231207
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    Kink motion in poly(vinylidene fluoride) form I (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2505-2515 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The diffuse-streak x-ray scattering intensity from poly(vinylidene fluoride) form I, which is caused by kink bands with GTnḠ (n odd) conformation contained in the crystallite, decreases with increasing temperature, while the intensity of the 001 reflection does not change. This is attributed to the disappearance of the kink bands in the crystallite, not to partial melting of crystallites containing kink bands. The disappearance of the kink bands suggests that kink motion takes place in the crystallite. Plots of the intensity of diffuse-streak scattering, estimated from the asymmetric part of the 001 reflection, against 1/T roughly give ΔHv = -4.6 kcal/mol. This suggests that the kink band is energetically more stable than the regular structure of form I.
    Additional Material: 10 Ill.
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  • 57
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    An x-ray diffraction study of nonlinear polyethylene. I. Room-temperature observations (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2517-2537 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this investigation on samples of high- and low-density polyethylene and ethylene-vinyl acetate copolymers, crystallinities φW and crystalline densities ρcW were obtained with the aid of wide-angle x-ray scattering (WAXS) methods. From small-angle x-ray scattering (SAXS) the following characteristics were obtained either directly or by combination with the WAXS data: values, or limiting values, of the crystallinity φS; crystal densities ρcS; thicknesses of the diffuse boundary layer; number-average thicknesses of the crystalline and amorphous layers; and both number and weight averages of the long periods. It was shown that a discrepancy between φS and φW cannot be attributed to the occurrence of large amorphous regions outside the regular stacks of lamellae; the data were reconciled by assuming that the WAXS crystallinities pertain to the cores of the crystalline lamellae, whereas part of the diffuse boundary layers is comprised in the values of φS. The ρcW and ρcS data of the nonlinear samples show systematic differences, which were attributed to partial incorporation of side groups in the crystalline regions at a concentration estimated to be of the order of 20-40% of the overall concentration. With increasing side-group concentration, the thickness of the core of the crystalline lamellae was found to approach the average length of the linear chain segments between side groups. On the basis of these observations a scheme for the crystallization of nonlinear polyethylene is proposed according to which a number of side groups is encapsulated by the growing crystal. The data can be explained by assuming that all chains, offered at a crystal face where growth takes place, crystallize directly, irrespective of whether the crystallizing stem carries a side group. Further crystallization would then proceed by chain folding at both ends of the first stem, until a noncrystallizable unit is met. In this scheme, allowance is made for about half the stems in the crystals to be connected by folds; this is required in view of the “overcrowding” effect. Finally, the effect of cooling rate and molecular weight on the thicknesses of the crystalline and amorphous layers is discussed, and differences between the amorphous densities of high-and low-density polyethylene are noted.
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    Stability of the γ form and the development of the α form in nylon 6 (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2549-2565 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The structure of nylon 6 fibers is analyzed by x-ray diffraction. Our results suggest that only two forms of nylon 6, α and γ, along with lattice distortion and crystallite size, are sufficient to explain the whole range of crystalline structures observed in nylon 6. The γ phase is the preferred initial form in a number of nylon 6 samples. The lattice distortion of the γ form along the chain axis varies from 0.8 to 2.4%, depending on the processing conditions. Upon annealing nylon 6 fibers, the α form is produced primarily by γ-to-α conversion in high-orientation fibers, while additional α form can also crystallize from the amorphous phase in low-orientation fibers. Finally, we show that α crystallites are favored during conditioning of poorly crystallized fibers in a humid atmosphere, and therefore fibers with α as the major crystalline form are produced upon drawing these conditioned fibers. Fibers drawn without lag time contain primarily the γ phase.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231212
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  • 59
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    An x-ray diffraction study of nonlinear polyethylene. II. Small-angle scattering observations near the melting point (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2539-2548 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method is presented for obtaining from the zeroth-order peak in small-angle x-ray scattering (SAXS) patterns the weight average of the thickness C of crystalline lamellae in polymers close to the melting point. The method fails if a first-order peak can be discerned to be superimposed on the zeroth-order peak. The method was applied, together with the one described in Part I of this series for obtaining the number average of C, to three polyethylene samples of different side-group content which were heated to temperatures close to the melting point. While heating always causes an increasing number of lamellae to melt, a linear sample also shows pronounced thickening of the remaining lamellae. This effect, however, decreases with increasing side-group content, and is virtually absent in a vinyl acetate copolymer containing 53 side groups per 1000 C atoms. A qualitative explanation for the role of the side groups in limiting the crystal thickening processes is put forward. By comparing results obtained after isothermal annealing and during isothermal crystallization from the melt it is concluded that at temperatures close to the melting point the polymers approach a final state which no longer depends on the thermal history of the sample.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231211
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    Crazing as quasifracture in an oriented viscoelastic medium (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2579-2597 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Crazes of different types occur in polymeric systems. Long, sparse crazes develop in less oriented molecular systems, while fine, short, dense crazes occur in highly oriented molecular systems. Different crazing mechanisms and different models may have to be studied for a better understanding of these differences. However, in this report, using one model and one theory, an analysis has been made of the differences in the geometry of craze development. By emphasizing the mechanism of molecular orientation, it is found that the basic differences are essentially attributable to the variation of the anisotropy of the material system as a result of large deformation rather than to any fundamental differences in the crazing mechanism.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231214
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    Light-scattering characterization of poly(ethylene terephthalate) (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2567-2578 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: By using a closed-circuit filtration system, we have succeeded in clarifying poly(ethylene terephthalate) (PET) dissolved in hexafluoroisopropanol (HFIP). Such static properties as the radius of gyration Rg, the weight-average molecular weight Mw, and the second virial coefficient A2 and such dynamic properties as the translational diffusion coefficient D, or its equivalent hydrodynamic radius Rh, and the second (diffusion) virial coefficient kd were determined for several PET samples of different molecular weights by using light-scattering intensity and linewidth measurements. An empirical relation between Do (or Rh) and Mw was established: Rh = (1.77±0.15)X10-2 Mw+0.58±0.01 with Rh and Mw expressed in units of nanometers and grams per mole, respectively. The empirical exponent αD(ca. 0.58±0.01) is in good agreement with the less precisely determined intrinsic viscosity/molecular weight exponent αη (ca. 0.71±0.02). Several intensity correlation functions were measured very precisely using long accumulation times. A Laplace inversion was performed using the singular-value decomposition technique. The approximate molecular weight distribution (MWD) determined by light-scattering spectroscopy was in reasonable agreement with a completely independent determination of MWD using gel permeation chromatography (GPC). It was interesting to note, though not surprising, that GPC showed emphasis on lower-molecular-weight fractions, while light-scattering emphasized higher-molecular-weight fractions. The agreement further strengthens some complementary aspects of the two techniques.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231213
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    Epitaxial crystallization of polyethylene and paraffin on oriented polypropylene (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2623-2627 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231217
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    Studies on comblike polymers. X. Characterization of comblike polyesters by 13C NMR spectroscopy (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2611-2621 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The 13C NMR spectra of aromatic comblike polyesters obtained from 1,2-icosanediol and isomeric phthalic acids are reported and discussed. The analysis shows that the most informative spectral regions are those of the carbonyl and quaternary carbon resonances, whose peak multiplicities have been interpreted in terms of dyad and triad sequences. The results indicate that the extent of structural characterization possible for the polymers examined is dependent on the type of isomerism of the aromatic acid involved.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231216
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    Monte carlo simulations relevant to the upturns in modulus observed for natural rubber at high elongations (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2629-2632 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231218
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    Improvement in polypropylene thermal oxidative stability by annealing under an inert atmosphere (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2633-2634 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180231219
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    Estimation of the equilibrium modulus of rubber networks by nonlinear regression analysis (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2635-2635 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180231220
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    Rebuttal to “comments on ‘some evidence against the existence of the liquid-liquid transition. III. The evaluation of the TLL event by differential scanning calorimetry’ ” (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 13-19 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It is proposed here that readily observable viscous deformation is the common underlying phenomenon which is reflected in several kinds of evidence advanced for the existence of a liquid-liquid transition TLL. These include flow temperature Tf measurements, microscope hotstage coalescence, and differential scanning calorimetry (DSC) measurements. A DSC peak observed at Tg in high-molecular-weight bulk-polymerized poly(methyl methacrylate) is discussed in terms of the presence of conformations of low entropy.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230102
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    Comments on “some evidence against the existence of the liquid-liquid transition. III. The evaluation of the TLL event by differential scanning calorimetry”This paper is in two parts, using a common set of references. Part A was submitted in January 1983 with the same title and purpose implied by that title, but with minor modifications suggested by referees. Part B responds to the rebuttal to Part A by Chen et al. in the following paper and adds pertinent new material in response to their rebuttal. (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1-12 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The volatile-component evaporation mechanism proposed by Chen et al. to explain molecular-weight-dependent endothermic peaks found at temperatures above Tg in anionically prepared polystyrenes (PSs) on first heating in open DSC pans is inconsistent with several bodies of literature data which were overlooked, including similar data with closed DSC pans. Moreover, this mechanism appears deficient in explaining details of the dependence of the endothermic peak temperature on M̄n both below and above the entanglement molecular weight Mc, with a sharp increase in slope at Mc. The original fusion-flow mechanism of Stadnicki et al. is compatible with all other known literature data including results on thermal PS and PMMA fractions. Hot-stage microscope examination of powdered anionic PSs supports the Stadnicki mechanism from M̄n = 1900 to at least M̄n = 350,000. Addition of small amounts (ca. 1 wt %) of benzene or ethylbenzene to PS results in open-pan DSC traces without endothermic peaks but with an endothermic slope change indicating gradual loss of diluent at decreasing rate as the temperature is increased from below Tg up through the TLL region.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230101
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    Carbon-13 NMR relaxation and transitions in polymers (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 367-385 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: High-resolution proton-decoupled carbon-13 nuclear magnetic resonance relaxation parameters have been obtained as a function of temperature for a set of completely amorphous polymers, semicrystalline polymers, and a series of ethylene-vinyl acetate copolymers. With these samples the nature of the glass temperature, other postulated amorphous transitions, and the β transition were investigated. For the completely amorphous polymers, the average correlation times depend on temperature according to the Williams-Landel-Ferry relation. Spectral collapse occurs at temperatures whose ratio to Tg is in the range 1.2-1.4 and corresponds to a correlation time of about 10-7s. The loss of resolvable spectra is demonstrated to be a consequence of experimental methods and is not due to the occurrence of another amorphous transition. Both the methylene and methine carbons can be resolved for the ethylenevinyl acetate copolymers. Although the correlation time for the methylene carbon is continuous and resolvable through the β transition region, the methine branch-point resonance is lost. The implication of these results to the molecular nature of the β transition is discussed.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230211
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    Phase transitions in mesophase macromolecules. V. Transitions in poly(oxy-1,4-phenylene carbonyl-co-oxy-2,6-naphthaloyl) (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 521-535 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The copolymer system HBA (4-hydroxybenzoic acid) and HNA (2,6-hydroxyhaphthoic acid) has been studied mainly by means of differential scanning calorimetry. Heat capacities for the two homopolymers and three copolymers are reported from 175 to 650 K. The heat capacities are additive with composition. The whole copolymer system represents an example of a mesophase intermediate between the liquid-crystalline and the condis-crystalline state with a small amount of crystallinity. The disordering transitions (520-620 K) have a eutecticlike phase diagram. The transitions to the isotropic states occur above the decomposition temperatures (600-700 K). The glass transitions (377-434 K) show normal changes in heat capacity (31-34 J/K mol), but are broadened to as much as 200 K.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230309
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    Rheo-optical studies of concentrated polystyrene solutions subjected to transient simple shear flow (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 575-589 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Concentrated polystyrene solutions were investigated on the inception and cessation of simple shear flow by means of the technique of two-color flow birefringence. Both monodisperse solutions of various molecular weights and bimodal mixtures were studied. The molecular weight affected both the amount of overshoot in the birefringence and the response time on the inception of shear flow. Large overshoots in birefringence, up to 250%, and undershoot in the orientation angle were observed. The shear stress and the first normal stress difference were calculated by using the stress-optical rule. The amount of strain at the peaks in the stress growth curves are presented along with the steady-state viscosity and primary normal stress coefficient. The experimental results are compared qualitatively with theoretical predictions of various molecular models.
    Additional Material: 16 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230313
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    Macromolecular pair correlation functions from fluorescence depolarization experiments (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 591-599 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Depolarization of fluorescence resulting from the transport of electronic excitations in chromophore-containing polymers is investigated as a technique for detecting deviations from ideal-chain statistics. An approximate expression for the fluorescence anisotropy that depends only on the pair correlation function of chromophore labels is presented. This approximation is shown to be accurate for particular cases of long-range correlations, short-range correlations, and no correlations among chromophore positions. The formalism allows fluorescence depolarization experiments to be used as a probe of macromolecular pair correlation functions.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230314
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    Low-frequency excitations in amorphous poly(vinyl acetate) (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 609-614 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Raman-active modes have been detected in amorphous poly(vinyl acetate) in the frequency region 20-160 cm-1. The low-frequency spectrum appears as a broad band for all three molecular weights examined. Spectra were recorded at two temperatures, 293 and 77 K, and found to show similar characteristics at both temperatures. The presence in solid amorphous polymers of broad structureless bands in general and their significance are discussed.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230401
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    Crystallization in oriented poly(ethylene terephthalate) fibers. I. Fundamental aspects (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 653-674 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The nature of crystallization- and mobility-induced changes during annealing of melt-spun poly(ethylene terephthalate) precursor fibers of a range of orientations has been examined. The kinetics of crystallization and the accompanying orientational changes have been studied under conditions of constant, low tensile stress, with the accompanying dimensional changes and under a constraint against shrinkage in length, with the stress developed being monitored. The effects of precursor orientation and externally imposed constraints on the course of the fundamental crystallization and orientational relaxation processes are revealed. Oriented crystallization has been shown to have a significant effect on the stress developed and on the dimensions of oriented precursor fibers, with a strong tendency to spontaneously extend as a consequence of the reorientation of crystallizing segments predominantly along the preferred fiber direction. The sequence in which crystallization and major orientational relaxation, if any, occur is found to have a profound effect on the structure and thus the deformability of oriented fibers after annealing above the glass transition temperature.
    Additional Material: 20 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230404
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    Relaxation of chemical potential and a generalized diffusion equation (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 675-682 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of slow structural relaxation in a solvent of high viscosity on the chemical potential driving the diffusion of penetrant molecules is described by a generalized diffusion equation with a memory term. The linearized version of this equation is solved for some special cases, and the correlation function of concentration fluctuations in thermodynamic equilibrium is calculated. As a result of the memory term, for very slow relaxation two different stages of the diffusion process can be distinguished.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230405
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    Energy absorption in polymer crazing (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 683-693 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The total energy absorbed by a craze during its development in creep is analyzed and calculated on the basis of a time-dependent theory of crazing. Experimental measurements of the craze length have been utilized in the energy calculations. For polystyrene the initial energy absorption in the craze region is found to be several hundred times that in the uncrazed medium. This ratio decreases sharply in a short period of time to about 50 to 1 and less and remains low afterward. For polycarbonate, somewhat similar behavior has been found. The initial strain energy absorption by crazing is about 200 times that in the uncrazed region. The energy ratio reduces rapidly to about 55 to 1 and tends to level off thereafter. However, in general, the amount of strain energy absorbed does increase as a function of time, as it should.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230406
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    Bead-spring model for adsorbed polymer chains in shear flow: Hydrodynamic interaction (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 695-707 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We consider the hydrodynamic interaction between two absorbed polymer chains in a simple shear flow, each modeled by a bead connected to the wall by a linear spring. It is concluded that hydrodynamic interaction between the beads or between the beads and the wall cannot be responsible for the experimentally observed increase in hydrodynamic thickness.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230407
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    Rheological and DSC changes in poly(vinyl alcohol) gels induced by immersion in water (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1803-1811 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(vinyl alcohol) (PVA) gels were prepared by freezing and thawing aqueous solutions at temperatures from -20 to 15°C. The temperature was varied periodically by use of a computer. The endothermic DSC peak was observed for the PVA gels at about 60°C for five specimens of different degrees of saponification (DS). Another endothermic peak was also observed in the range 67-80°C, and this peak shifted to higher temperature with increasing DS. These endothermic peaks shifted to lower temperature on immersion of the PVA gels in water. The dynamic Young's modulus E′ at room temperature was also decreased by immersion of PVA gels in water; E′ decreased monotonically with increasing temperature for PVA gels without immersion in water, while it increased up to a certain temperature and then decreased with increasing temperature for PVA gels in water. The X-ray diffraction showed a characteristic crystalline pattern for PVA gels of higher DS, and this peak was intensified by stretching the gel.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230906
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    Study of spin-lattice relaxation and local motion in dissolved poly[2,2-propanediylbis(3,5-dimethyl-4, hydroxyphenyl)carbonate] (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1793-1802 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Proton and carbon-13 spin-lattice relaxation times are reported for 10-wt % solutions of tetramethyl bisphenol-A polycarbonate. The relaxation times for both nuclei were measured at two Larmor frequencies and as a function of temperature. These relaxation times are interpreted in terms of three motions: segmental motion, restricted rotational diffusion, and backbone methyl-group rotation. The Hall-Helfand correlation function is used to describe the segmental motion. Internal rotation is described by the usual Woessner approach and restricted anisotropic rotational diffusion by the Gronski approach. As demonstrated by its higher activation energy, correlated segmental motion appears to be slower than the unsubstituted polycarbonate of BPA. In addition, the single-transition processes seem to be still less important than correlated backbone transitions. Phenylene-group rotation is described in terms of restricted rotational diffusion instead of complete anisotropic rotation. The time scale for backbone methyl-group rotation is comparable to that in BPA, a fact indicative of weaker cooperativity between this motion and the other motions. Rotation of the methyl group attached to the phenylene ring is too fast to significantly contribute to relaxation except by partially averaging the dipole-dipole interactions. The higher activation energies for segmental motion observed in solution for this methyl-substituted polycarbonate relative to the unsubstituted polycarbonate parallel a significant increase in the glass transition temperature observed for the substituted material. The restricted pheylene-group rotation in solution is also parallelled by a large upward shift of the low-temperature loss peak in the glassy polymer.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230905
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    The role of molecular diffusion in the adhesion of EPDM and EPR elastomers (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1823-1830 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Adhesion of lightly crosslinked sheets of EPDM (ethylene-propylene-diene terpolymer) to themselves and to a Mylar substrate has been investigated over wide ranges of peel rate and test temperature. The effect of incorporating ethylene-propylene copolymer (EPR) before crosslinking, to yield a loose macromolecular network containing dissolved linear EPR macromolecules, was also studied. The self-adhesion of these materials was found to be much greater than their adhesion to Mylar, over a wide range of effective peel rates. This is attributed to interdiffusion of EPR and EPDM molecular strands. At extremely low peel rates the enhancement of adhesion was smaller, probably because of back-diffusion, and at high rates, the strength of adhesion became high in all cases. These results are compared to those obtained previously for polyisobutylene-co- isoprene networks containing linear polyisobutylene molecules. The enhancement of self-adhesion at intermediate rates of peel was considerably greater for the EPDM-based materials, probably because of a lower degree of crosslinking and a greater tendency to form molecular entanglements.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230908
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    Differential sorption in viscoelastic fluids (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1831-1855 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The diffusion of organic solvents in concentrated polymer solutions often deviates from the predictions of Fick's second law, especially when the solution is in the glassy state; such behavior is called anomalous or non-Fickian. This paper analyzes the one-dimensional sorption of a solvent into a concentrated polymer solution under a small driving force. The treatment includes the effect of an entanglement network on the process as postulated by Thomas and Windle. The deformation of the entanglement network during sorption creates a normal stress on the solvent equivalent to an osmotic pressure. Including the osmotic pressure gradient in the driving force for solvent diffusion leads to a linear, third-order partial differential equation for solvent concentration distributions. By evaluating the physical constants in the theory for the system methyl acetate/poly(methyl methacrylate) at 30°C the treatment is shown to predict the anomalous characteristics found experimentally.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230909
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    A SAXS study of a single crack and craze in plasticized polystyrene (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1857-1867 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Small-angle x-ray scattering (SAXS) was used to study the structure along a single craze that had broken down to form a crack along part of its length. This study was made possible by use of radiation from the synchrotron source CHESS which is sufficiently intense to permit examination of just a single craze. The total scattering from the craze was in excellent agreement with that expected from a knowledge of its dimensions and fibril volume fraction and width. This fact adds confidence to the interpretation of the scattering pattern of the craze as part diffraction, part reflection, and demonstrates that SAXS is a technique that may be used to measure craze volume within a sample. The craze was shown to grow in width by surface drawing with a constant structure, and then the fibrils broke to form a crack. The broken fibrils contracted and their diameters increased but they appeared to stay parallel with a constant fibril-axis radial distribution function.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230910
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    Far-infrared studies of microphase separation in sulfonated ionomers (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1869-1881 
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    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Far-infrared spectra of a series of un-neutralized and neutralized lightly sulfonated polystyrenes with varying sulfonation levels have been investigated to seek spectroscopic evidence for microphase separation known to control the physical properties of these polymers. Broad, strong absorbance bands, not found in the spectrum of unmodified polystyrene, are observed in the spectra of the sulfonated analogs. The effects on the far-infrared spectra both of sulfonation level and of the mass and charge of the neutralizing cation are discussed in terms of cation motion and the formation of ion-rich domains.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1985.180230911
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    Small-angle scattering analysis of hard-microdomain structure and microphase mixing in polyurethane elastomers (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1883-1913 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The microdomain structure of a series of segmented polyurethane block copolymers is characterized by small-angle x-ray and neutron scattering analyses. The materials contain hard segments formed from 4,4′- diphenylmethane diisocyanate (MDI) and butanediol (BD), and range in hard-segment content from 20 to 80% by weight. The results provide evidence for a transition from discrete to continuous hard-microdomain morphology as the hard-segment content is increased above ca. 50%. The measured concentration dependences of the interdomain spacing, specific interfacial area, diffuse microphase boundary thickness, and scattering invariants are used to examine the validity of present models for hard-microdomain structure. The observed behavior corresponds well with the general predictions of a lamellar model wherein partially coiled hard-segment sequence configurations are allowed. The thickness of the hard microdomains extracted from the model corresponds to approximately four hard-segment repeat units. Scattering invariant calculations are used together with determinations of the soft-microphase glass transition temperatures to examine possible models for microdomain mixing. These calculations suggest that both the hard and soft microphases are phase mixed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230912
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  • 85
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    The structure of MDI/BDO-based polyurethanes: Diffraction studies on model compounds and oriented thin films (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1915-1932 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyurethanes based on MDI/BDO are known to crystallize in three distinct forms. Two of these crystal structures, type II and type III, have been characterized by electron and x-ray diffraction experiments on model compounds and oriented thin films of a 77% hard-segment polyurethane elastomer. The model compounds were of the form BDO(MDI/BDO)n with n = 1, 2, 3. Results from the model compounds indicate that the MDI/BDO repeat crystallizes in the type-II structure, which has a contracted conformation with a monomer repeat length of 1.70 nm. MDI/BDO-based polyurethanes also exhibit the type-II structure under quiescent crystallization conditions. Studies of oriented thin films of an MDI/BDO-based polyurethane indicate that a change in crystal form occurs on stretching to the fully extended monomer conformation. This crystal form is termed type III and has a monomer repeat length of 1.92 nm.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230913
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  • 86
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    Electronic Resource
    Extraction and sorption studies using linear polymer chains and model networks (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1933-1940 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Model networks have been prepared by tetrafunctionally endlinking linear polydimethylsiloxane (PDMS) chains having molecular weights Mn in the range 2000-15,000 g mole-1. The first series of networks were prepared from mixtures containing known amounts of unreactive linear PDMS chains with molecular weights Md between 1000 and 16,000 g mole-1. Rates of extraction were used to estimate diffusion coefficients; as expected, they were found to increase with increase in molecular weight Mc = Mn between crosslinks, but to decrease with increase in Md. The ease with which all of such a diluent could be removed showed the same dependence on Mc and Md. A second series of networks was prepared from the same reactive PDMS chains without diluents. Sorption and extraction studies using the same diluents were then carried out. The diffusion coefficients for sorption were found to be in the range (1.7-15.0) × 10-12 m2 s-1 and depended on both Mc and Md. The amount of diluent absorbed at equilibrium was between 10 and 70%, which is in good agreement with predictions from the Flory equation for dilation in networks, with account of constraints on crosslink fluctuations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230914
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  • 87
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    Phase separation phenomena in solutions of poly(2,6-dimethyl-1,4-phenyleneoxide) in mixtures of trichloroethylene, 1-octanol, and methanol: Relationship to membrane formationA part of this work was presented at the First Europe-Japan Congress on Membranes and Membrane Processes, Stresa, Italy, June 18-22, 1984. (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1941-1955 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The phase boundaries in the quaternary system consisting of the polymer poly(2,6-dimethyl-1,4-phenyleneoxide) (PPOPPO is a registered trademark of the General Electric Company.), the solvent trichloroethylene (TCE), and the nonsolvents 1-octanol (OcOH) and methanol (MeOH) are determined. The kinetics of crystallization are investigated by pulse-induced critical scattering. The formation and properties of PPO membranes are discussed in relation to the phase separation phenomena.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230915
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  • 88
    Electronic Resource
    Electronic Resource
    Short-branch formation via the roedel mechanism in copolymers of ethylene and vinyl acetate (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1957-1965 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A realistic rotational isomeric state model has been used to estimate the relative probabilities of the formation of various types of short branches in ethylene-vinyl acetate copolymers that are rich in ethylene. Butyl is predicted to be the most common short branch in all of the copolymers examined, although it is less common in the copolymers than in low-density polyethylene. The major factor responsible for the suppression of the R04 backbiting intrachain radical transfer is the increased preference for trans states at the mainchain bonds flanking the attachment site for an isolated acetoxy side chain.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230916
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  • 89
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    The local structure of blends of polystyrene and poly(2,6-dimethylphenylene oxide) (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1967-1974 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polystyrene (PS) and poly(2,6-dimethylphenylene oxide) (PPO) are miscible over the complete composition range. The addition of 30-40% PPO to PS changes the mechanical behavior of the material from brittle to tough and ductile. The x-ray scattering curves from unoriented and oriented samples of PS and of PPO are compared with those from a 50/50 blend. The introduction of PPO into PS disrupts microsegregation of phenyl groups into stacks which are a feature of the pure polymer and which may be responsible for formation of sharp shear bands and brittle behavior of PS. The local structure of the blend is significantly different from both PS and PPO.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230917
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  • 90
    Electronic Resource
    Electronic Resource
    Dynamic behavior of flexible polymers at a solid/liquid interface (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1997-2008 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mean time spent by a macromolecule at a solid/liquid interface is analyzed in the region of adsorption saturation. The method consists of carrying out preliminary adsorption with radioactively labeled high-molecular-weight polyacrylamide and subsequently exposing the surface to a solution of unlabeled polyacrylamide. It was found that, apart from a small fraction of polymers “loosely” attached, the exchange between labeled and unlabeled polymers takes place at the interface at a very slow rate. Furthermore, desorption of surface molecules occurs only in the presence of a solution, and then the rate of desorption increases proportionally to the number of molecules in the solution. A mechanism based on a bimolecular chemical exchange process is proposed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180231002
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  • 91
    Electronic Resource
    Electronic Resource
    Miscibility and deformation behavior in some thermoplastic polymer blends containing poly(styrene-co-acrylonitrile) (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1975-1995 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Miscibility in blends of poly(styrene-co-acrylonitrile) (PSAN) with several other polymeric components has been investigated over a range of compositions by means of thermal analysis and transmission electron microscopy. Systems in vestigated were (i) PSAN/polycarbonate (PC), (ii) PSAN/styrene-maleic anhydride-methyl methacrylate terpolymer (S/MA/MM), (iii) PSAN/polynorbornene nitrile (PNN), and (iv) PSAN//S/MA/MM//PC. PSAN/PC was demonstrated to be partially miscible in all proportions over the PSAN copolymer composition range 23-70 wt % AN, while the miscibility or lack thereof of PSAN//S/MA/MM depended on the relative AN and MA contents of the PSAN and S/MA/MM, respectively. In contrast, PSAN/PNN was found to be immiscible in all proporations, while the system PSAN//S/MA/MM//PC was shown to be partially miscible. Deformation studies performed on rubber-modified versions of these blends defined deformation mode and microstructural deformation behavior. Dual extensometer tensile testing yielded relative contributions of crazing and of plastic flow, which correlated both with blend composition and with toughness. TEM observations of deformed specimens indicated a deformation process in the multiphase matrix blends consisting of craze initiation and propagation in the rubber-containing phase, craze arresting in the ductile second matrix phase, and coordinated extensive deformation of the matrix phases and of the rubber particles, where the ability to support the latter coordinated forms of deformation were observed to increase with increasing proportion of plastically deforming phase.
    Additional Material: 23 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180231001
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  • 92
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    The effect of spherulitic truncation on small-angle light scattering (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2059-2084 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effects of spherulitic truncation on the Hv small-angle light-scattering (SALS) patterns are determined by computer simulation of spherulite nucleation and growth. The simulation is carried out for simultaneous and sporadic nucleation of two-dimensional spherulites and simultaneous nucleation of three-dimensional spherulites. The scattered intensity differences between truncated spherulites and round spherulites are determined as functions of the type of growth and the volume (or area) fraction of spherulites. Methods for the determination of certain geometrical characteristics of spherulites systems by SALS are developed. These characteristics include the volume (or area). fraction of spherulites, the average spherulite radius, and the average spherulite volume (or area). The results of this study are essential in the quantitative analysis of Hv SALS from spherulitic systems. The simulation process is readily extendable to the examination of other morphological phenomena by SALS.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180231007
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  • 93
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    Electronic Resource
    Quantitative small-angle light scattering studies of the melting of poly(ethylene terephthalate) (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 2085-2107 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Quantitative Hv small-angle light-scattering (SALS) studies of the melting of poly(ethylene terephthalate) (PET) have been performed. The results are compared with those from differential scanning calorimetry (DSC). It is found that fully grown spherulites melt over a temperature range of about 20°C without change in spherulite size, number, or internal disorder. The decrease in Hv SALS intensity is due to a decrease in spherulitic crystallinity over the melting range. The corrected experimental intensities are lower than, but in reasonable agreement with, the theoretically predicted intensities based on the DSC results. Procedures are presented for the quantitative analysis of Hv SALS intensities from spherulitic systems, including the corrections for the experimental, external disorder, and internal disorder effects.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180231008
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  • 94
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    Electronic Resource
    Monte Carlo simulation of the crystal structure of the low-temperature phase of polytetrafluoroethylene (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 771-786 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An energy analysis based on molecular field theory and Monte Carlo simulation is carried out for the crystal structure of the low-temperature phase of polytetrafluoroethylene (PTFE). PTFE molecules in right-handed and left-handed 13/6 helical conformation are assumed to be packed in a hexagonal array, with each molecule having 13 possible orientations around the chain axis. Interactions between nearest-neighbor chains are calculated from van der Waals interactions between nonbonded C-C, C-F, and F-F atom pairs. First, an approximate molecular field calculation is made of the critical fluctuation of the chain orientation at the order-disorder transition point. This suggests that the low-temperature phase has two chain stems in the unit cell. The Monte Carlo calculation, similar to that used for spin systems, is then applied to the equilibrium packing mode in the low-temperature phase. A crystal structure containing two chain stems in the unit cell is again obtained. A large amount of disorder in the chain orientation is indicated and is believed to be essential in the PTFE crystal.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230412
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  • 95
    Electronic Resource
    Electronic Resource
    Fracto-emission from filled and unfilled polybutadiene (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 873-888 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We further examine the mechanisms involved in the emission of electrons and positive ions from polybutadiene accompanying fracture. Experimental evidence is given in support of a previously presented model involving a microdischarge accompanying fracture which excites the fracture surfaces by particle bombardment. Calculations of the time dependence for the emission from such excitations for both isothermal and thermal stimulation from a simple trap model are presented. We conclude that both filled and unfilled polybutadiene are experiencing the same excitations except at a considerably reduced intensity for the unfilled material.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230504
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  • 96
    Electronic Resource
    Electronic Resource
    Effect of polydispersity on the cloud-point curves of polymer mixtures (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 917-924 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method is presented for the calculation of cloud-point curves of polymer-polymer mixtures when the polymers involved are polydisperse. The method is based on the Flory-Huggins free energy of mixing with a concentration-independent χ parameter. Numerical results are given for cases in which the molecular weight distributions are represented by the Schulz-Flory type. When the two polymers have similar average molecular weights and polydispersities, the cloud-point curves become flatter as the polydispersity increases. When the two polymers have similar average molecular weights but differ in polydispersity, the cloud-point curves become more skewed as the difference in the polydispersity increases. The results point out that, if the polydispersity effect is not properly accounted for, the value of χ deduced from experimental cloud points is liable to be in error, especially with regard to its temperature coefficient and its concentration dependence.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230506
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  • 97
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    Influence of tacticity on Tβ, Tg, and TLL in poly(methyl methacrylate)s by the method of thermally stimulated current (TSC) (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 889-916 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The thermally stimulated-current method (TSC) has been employed to determine the temperatures and intensities of Tβ, Tg, and T 〉 Tg for pure isotactic, pure syndiotactic, and five atactic specimens with syndiotactic triad content from 49.5 to 75%; Tg was found to increase linearly with syndiotactic triad content as Tg (°C) = 48.0 + 0.856 (% syn), with R2 = 0.970 standard error 5.6°C; Tg for the syndiotactic specimen is 136.6°C measured, 133.6°C calculated. Several atactic specimens exhibit a second glass temperature 15 to 35 K above the regression line ascribed to some pure syndio content, and/or some isotactic-syndiotactic stereocomplexes. All specimens exhibited the liquid-liquid or TLL transition (relaxation) which increases linearly with 100-% isotactic triad content. Isotactic PMMA shows a T′LL relaxation 50 K above TLL. The Tg and TLL values obtained correlate extremely well with values from differential scanning calorimetry (DSC) determined in a separate study, as well as with most literature data. Intensities of Tg and TLL by TSC are greatest for isotactic, next for syndiotactic, with a broad, low minimum for atactic materials. The intensity of a β relaxation increases slowly from isotactic to syndiotactic. The TLL found by TSC compares well with literature values for isotactic PMMA obtained by several methods, and TLL in the atactic region compares well with literature values for atactic material. The ratio TLL/Tg ranges from 1.09 to 1.20 with no dependence on tacticity. Tg follows simple Arrhenius behavior with enthalpies of activation about one-half of the values normally calculated from dielectric and mechanical loss. The frequency dependences of TLL and T′LL follow a Vogel-WLF relationship with temperature. The origin of TLL is discussed in terms of the Frenkel hypothesis of segment-segment interaction. Evidence for TLL and TLL from a variety of methods indicates that these two temperatures are not artifacts of the TSC method.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230505
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  • 98
    Electronic Resource
    Electronic Resource
    Polymer migration in newtonian fluids (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 955-971 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The theory of Freed and Edwards is used to investigate polymer migration in nonhomogeneous flow fields with confined geometry. Polymer migration from the main flow originates in three effects: (i) nonhomogeneous flow-field effect, (ii) the confined-geometry effect, and (iii) the concentration effect. General correlation function formulas for these three effects are explicitly derived. Some specific examples are illustrated and solved by using the harmonic dumbbell and Rouse-Zimm models.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230509
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  • 99
    Electronic Resource
    Electronic Resource
    Conformational behavior of styrene-dymethylsiloxane block copolymers in dilute solution (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 991-1000 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: To determine the behavior of a copolymer is dilute solution, a viscosity study has been performed on a polystyrene-polydimethylsiloxane block copolymer in three solvents presenting different thermodynamic conditions. The results are discussed in relation to a mixture of homopolymers and a segregated model. The unperturbed dimensions, obtained by the Stock-mayer-Fixman method, are intermediate between those of the parent homopolymers. The intrinsic viscosity measured in a good solvent, toluene, was close to the weighted averages of those of the corresponding homopolymers of equal molecular weight, but higher in decalin and in butanone, θ solvents for PS and PDMS, respectively. According to the low value obtained for the interaction parameter, the chain is slightly expanded as a result of the interactions between the unlike monomer units. Both segregation and random conformation would probably occur, depending on the quality of the solvent.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230511
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  • 100
    Electronic Resource
    Electronic Resource
    Sorption and diffusion of toluene in isotropic and oriented linear polyethylene (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 973-989 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Sorption and diffusion of toluene vapor in linear polyethylene with mass-fraction crystallinity between 0.48 and 0.82 and draw ratios λ up to 10 have been studied at 30°C. The sorbed concentration in the amorphous phase Ca is little affected by crystallinity, indicating that the free-volume fraction is roughly the same for all isotropic samples. However, the diffusion path becomes more tortuous with increasing crystalline content, thereby leading to a sixfold drop in the zero-concentration diffusion coefficient D0. Drawing has more drastic effects, reducing Ca and D0 by factors of 4 and 60, respectively, as λ increases to 10. These large changes result from the transformation of the initially spherulitic material into a fibrous structure, which is composed of aligned microfibrils with taut tie molecules lying on the outer boundaries. The effects of crystallinity and orientation on the concentration dependence of the diffusion coefficient are also discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230510
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