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  • 1
    Electronic Resource
    Electronic Resource
    Preparation, characterization, and porperties of optically active poly(α-methyl-α-ethyl-β-propiolactones) (1981)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 19 (1981), S. 1781-1793 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: S(-) and R(+) enantiomers of α-methyl-α-ethyl-β-propiolactone (MEEPL) were prepared in an eight-step synthesis with respective optical purities of 99 and 97% determined by 1H-NMR (250 MHz) spectroscopy. Polymers (PMEPL) of different enatiomeric compositions were prepared with an anionic-type initiator. Substantial differences in physical properties were observed between the racemic and optically pure polymers; for example, the melting point of the latter is 42°C higher than that of the former. Chiroptical properties of PMEPLs are reported. The 13C-NMR (100.62 MHz) spectra of the polymers indicated that the distribution of configurational units in the macromolecular chain is random.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1981.170190717
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  • 2
    Electronic Resource
    Electronic Resource
    Pyrolysis mass spectrometry of terephthalate polyesters using negative ionization (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 119-129 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The usual method of studying thermal degradation mechanisms of polymers in vacuo is to use electron ionization pyrolysis mass spectrometry. This can lead to mass spectral fragmentation from the 70 eV electrons used. Low energy electrons (10-15 eV) produce a low abundance of positive ions. However, if a molecule is prone to capture a thermal energy electron, then negative ions are produced in high abundance. This report describes the negative ion pyrolysis mass spectrometry of polyethylene terephthalate and polybutylene terephthalate.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.170200113
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and properties of miscible epoxy/acrylic interpenetrating polymer networks (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 3827-3842 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three series of epoxy/acrylic interpenetrating polymer networks were prepared by the simultaneous polymerization of diglycidyl ether of bisphenol A, crosslinked with an aliphatic diamine, diglycidyl ether of bisphenol A dimethacrylate, bisphenol A dimethacrylate, and diethoxy bisphenol A dimethacrylate. Under the conditions provided it is believed that the two networks form simultaneously but independently. Differential scanning calorimetry and dielectric measurements indicate that these polymer networks are miscible because they exhibit a single, sharp glass transition temperature, the values of which, however, are lower than predicted by the law of mixture. This decrease may be due in part to the dilution of one network by the other and to the resulting breakage of intramolecular interactions. It is also due, in part or in whole, to the presence of solvent and/or monomer impurities that act as plasticizers.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170221220
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  • 4
    Electronic Resource
    Electronic Resource
    Avrami analysis: Three experimental limiting factors (1980)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 18 (1980), S. 1655-1657 
    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 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1980.180180715
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  • 5
    Electronic Resource
    Electronic Resource
    Crystallization of poly(α-methyl-α-N-propyl-β-propiolactones) prepared from homogeneous and heterogeneous initiators (1981)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 19 (1981), S. 33-47 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Half-crystallization times t½, enthalpies of fusion ΔH, melting temperatures Tf glass transition temperatures Tg x-ray patterns, and morphologies were obtained for nine samples of poly(α-methyl-α-n-propyl-β-propiolactones) prepared from different homogeneous or heterogeneous initiators. The bulk of the results indicates that all samples can be classified into two categories: Polymers A having t½≏, 100 min, ΔH ≏ 26 J/g, Tf0 ≏ 376 K, Tg ≏ 275 K, and Polymers B having t½ ≏ 10 min, ΔH ≃ 14.5 J/g Tf0 ≏ 425 K and Tg ≏ 271 K. Polymers A were prepared with homogeneous initiators while polymers B were polymerized with heterogeneous intiators. The difference in crystallization behavior between polymers A and polymers B is certainly due to a difference in microstructure, brought about by the initiators, which has been qualitatively observed by NMR.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1981.180190104
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  • 6
    Electronic Resource
    Electronic Resource
    Studies of polylactone/poly(vinyl chloride), polylactone/poly(vinyl fluoride), and polylactone/poly(vinylidene fluoride) blends (1981)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 19 (1981), S. 1245-1253 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It is shown that polyvalerolactone/poly(vinyl chloride) (PVL/PVC) blends are miscible over all compositions since a single glass transition temperature Tg is observed, intermediate between those of pure PVL and pure PVC. Melting points, enthalpies of fusion and morphologies of PVL/PVC blends are also reported. It is also shown that polyvalerolactone, poly(α-methyl-α-n-propyl-β-propiolactone), poly(α-methyl-α-ethyl-β-propiolactone), and poly(caprolactone) are immiscible with poly(vinyl fluoride) and poly(vinylidene fluoride), despite the fact that all these polylactones are miscible with PVC. Differences in electronegativity, in atomic radius, and in molar attraction between the fluoride and the chlorine atoms are probably responsible for this difference in behavior.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1981.180190808
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  • 7
    Electronic Resource
    Electronic Resource
    Complex formation between enantiomeric polyesters (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 577-587 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this study, three different polymers were blended: a racemic PMEPL (PMEPL-RAC) which consists of a random distribution of repeat units of R or S configurations, an isotactic PMEPL made of repeat units of S configuration [PMEPL-S(-)], and a second isotactic PMEPL made of repeat units of R configuration [PMEPL-R(+)]. The acronym PMEPL stands for poly[α-methyl-α-ethyl-βpropiolactone]. The racemic PMEPL is optically inactive but the isotactic PMEPLs are optically active. In the first part of this study, an equimolar mixture of PMEPL-S(-) and PMEPL-R(+) was made. This racemate mixture leads to the formation of stereocomplex between the two polymers which has a melting point roughly 40°C higher than those of the isotactic polymers. The racemate morphology is composed of large spherulites. In the second part of this study, binary blends of PMEPL-S(-) and PMEPL-R(+) were prepared with an excess of one of the isotactic PMEPLs. The stereocomplex is preferentially formed between the isotactic polymers and this complex controls almost entirely the morphology of the sample. The enthalpy of fusion of the stereocomplex in the binary blends can be predicted. however, the excess isotactic polymer is trapped between the lamellae of the spherulites of the stereocomplex and its crystallization is hindered by the high viscosity of the partially crystallized medium. In the third part of this study, ternary blends were prepared. It is shown that PMEPL-RAC does not from a complex with the isotactic polymers. The PMEPL-S(-)/PMEPL-R(+) stereocomplex is again preferentially formed and it controls the morphology of the sample. It decreases the degree of crystallinity of both the excess isotactic polymer and the PMEPL-RAC. This control of the morphology is effective even in samples in which the sterocomplex accounts for only 3% of the total weight of the blend.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.180220404
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  • 8
    Electronic Resource
    Electronic Resource
    Fractionation in mixtures of polyethylene oxide fractions during crystallization (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 307-317 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two narrow-molecular-weight-fraction polyethylene oxides were mixed and studied by differential scanning calorimetry (DSC), small-angle x-ray scattering (SAXR), microscopy, and small-angle light scattering (SALS). DSC measurements indicate the presence of two melting points at each composition, leading to a eutectic diagram with a eutectic point located close to the axis of the constituent with the lower molecular weight. The depression in melting point of the higher-molecular-weight component allows the calculation of a thermodynamic interaction parameter of -0.09 between the two fractions, indicating that they are miscible in the melt despite the fractionation process occurring during crystallization. Two SAXR long periods are also observed at each composition, indicating phase separation during crystallization. These two phases are included into large spherulites, the structure of which depends mainly upon the crystallization characteristics of the higher-molecular-weight component. The other component must then crystallize between the spherulite lamellae. Finally, small spherulites of the order of the micron are observed from the SALS patterns inside the large spherulites (of the order of one millimeter as seen by microscopy). The two polyethylene oxide fractions give rise to different size SALS spherulites and both types of spherulites are present in the mixtures.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.180200212
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  • 9
    Electronic Resource
    Electronic Resource
    Crystallization of polydioxolan. III. Microscopy and dilatometric analysis of the crystallization kinetics (1980)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 18 (1980), S. 35-50 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Crystallization kinetics has been studied for a polydioxolan (PDOL) sample, over a wide temperature range, by dilatometry and microscopy. The dilatometry results can be analyzed using the Avrami equation. At temperatures higher than 22°C, the crystallization data must be analyzed in two steps: the first part of the curve corresponds to PDOL with a very disordered morphology (Phase I) while the second part of the crystallization curve is related to a spherulitic morphology (Phase II). The passage from the low to the high crystallization temperature region is associated with a change in the Avrami exponent from 3 to 4. The crystal surface free-energy product σσe was found to be 18 × 102 erg2/cm4, very close to that of polyoxymethylene. The crystallization kinetics was studied by microscopy over the temperature range-18 to 35°C. Growth and nucleation rates were recorded. Two phases are found only at temperatures higher than 22°C. The appearance of Phase II is related to a decrease in the growth rate of the sample. From the growth rates, the crystal surface free-energy product σσe was found equal to 17 × 102 erg2/cm4. The detailed analysis of the crystallization of the two phases reveals a complicated process which can be divided into four different steps: (a) growth of a disordered phase, Phase I; (b) nucleation of a higher birefringence structure; (c) propagation of a high birefringence phase; and (d) spherulitic growth, Phase II. The analysis of PDOL crystallization strongly suggests the presence of a hedrite → oval → spherulite transition: the hedrite formation corresponds to step (a), the oval formation to steps (b) and (c), and the spherulite formation to step (d).
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1980.180180104
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  • 10
    Electronic Resource
    Electronic Resource
    Miscibility of polycaprolactone/chlorinated polyethylene blends (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 191-203 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Blends of polycaprolactone (PCL) with chlorinated polyethylenes (PECls) having chlorine contents of 25, 30, 36, 42, and 48% by weight were prepared and studied by differential scanning calorimetry and small-angle light scattering (SALS). It was found that blends made with PECls containing 30% or more chlorine are completely miscible with PCL (a single glass transition temperature Tg is found) while the PCL/PECl(25) blends are immiscible. PCL crystallizes in the miscible blends at any composition and it has an enthalpy of fusion which decreases only slightly with PECl content. Blends in the PECl composition interval of 0-80% are spherulitic, as shown by SALS, but a rodlike morphology is found at the 85% composition and dispersed crystals are observed at higher compositions. It is suggested that the k parameter of the Gordon-Taylor equation can be taken as a measure of the strength of the specific interaction between PCL and PECl. Low values of k (0.26 and 0.35) are found for PCL/PECl blends but a higher value of k (0.51) has been reported for PCL/poly(vinyl chloride) (PVC) blends, indicating a stronger interaction in the latter mixtures. In agreement with these findings poly(α-methyl-α-n-propyl-β-propiolactone) and poly(valerolactone) are not miscible with PECl, whereas they were previously shown to be miscible with PVC.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.180200203
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