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  • 1
    Electronic Resource
    Electronic Resource
    Double melting behavior of cyclic tris(ethylene terephthalate) (1992)
    Springer
    Polymer bulletin 28 (1992), S. 593-599 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Cyclic tris(ethylene terephthalate) (CTET) was separated from oligomeric extract of poly(ethylene terephthalate) by the conventional solvent separation method. The structure of CTET was characterized by differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy. It is shown that the double melting behavior of meltcrystallized CTET is attributed to the morphological change created by heat-treatment. The effect of the morphological change on the crystal structure of CTET was also examined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296051
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of copolycondensation temperature on the reactivity ratios of bis(4-hydroxybutyl) terephthalate and bis(2-hydroxyethyl) terephthalate (1999)
    Springer
    Polymer bulletin 42 (1999), S. 9-16 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The effect of copolycondensation temperature on the monomer reactivity ratios of bis(4-hydroxybutyl) terephthalate (BHBT) and bis(2-hydroxyethyl) terephthalate (BHET) was investigated at 260, 270, and 280 °C, in the presence of titanium tetrabutoxide as a catalyst. Adopting 2nd order kinetics to polycondensation, the rate constants of polycondensation of BHBT and BHET, k 11 and k 22, were calculated to be 2.58, 1.30; 3.87, 2.24; and 5.29, 4.06 min−1. In addition, the rate constants k 12 and k 21 of cross reactions could be determined as 0.91, 3.00; 1.49, 4.42; and 2.13, 5.85 min−1 from a proton nuclear magnetic resonance spectroscopic analysis. The monomer reactivity ratios of BHBT were much larger than those of BHET, indicating the block nature of the copolycondensation, but the differences between monomer reactivity ratios were decreased with increasing polycondensation temperature, indicating that a probability of randomization was increased.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050428
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  • 3
    Electronic Resource
    Electronic Resource
    Kinetic studies on the formation of cyclic oligomers in poly(ethylene terephthalate) (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 2103-2118 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mechanism of cyclic oligomer formation has been kinetically studied by determining the rate of the formation of cyclic oligomers during melt of poly(ethylene terephthalate) (PET) at several levels of average molecular weight, which were obtained by fractionation and did not initially contain oligomers. The experimental rate equation of cyclic oligomer formation was introduced and then compared with the rate equation derived theoretically. The close agreement between the two equations suggested that the cyclic oligomer formation takes place according to cyclodepolymerization by the action of hydroxyl end groups in PET. The relation is represented as [C] = m·[OH]0·t1-n, where [C] is the concentration of cyclic oligomers, [OH]0 is the initial concentration of hydroxyl end groups, m and n are constants, and t is melting time. A method has also been developed for separating cyclic oligomers from PET using dimethylformamide (DMF) as a solvent.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170170719
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  • 4
    Electronic Resource
    Electronic Resource
    Blood compatibility of poly(ether urethane)-nylon 6 block copolymer (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 35 (1994), S. 171-178 
    Details
    ISSN: 0959-8103
    Keywords: poly(ether urethane)-nylon 6 block copolymer ; antithrombogenicity ; blood compatibility ; thrombus formation ; crystallite size ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Poly(ether urethane) (PEU)-nylon 6 A-B-A triblock copolymer was synthesised. Correlation of blood compatibility with morphological and surface energetic properties of the block copolymer film was investigated. The block copolymer film exhibited a suppressing effect on thrombus formation and it is suggested that controlling the crystallite size of the nylon 6 block in the block copolymer by regulating the copolymer composition is an important factor in the antithrombogenicity.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210350207
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  • 5
    Electronic Resource
    Electronic Resource
    Compatibility of nylon 6 and PMMA-oligoamide graft copolymer (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 567-576 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: PMMA-oligoamide graft copolymers, which were prepared by reacting poly(methyl methacrylate-co-methacryloyl chloride) with oligoamide, were blended with nylon 6. The compatibility was examined by measuring thermal properties such as melting point and crystallization temperature. It was observed that the melting point was significantly depressed as the grafted PMMA was added to nylon 6, suggesting that the blend is a miscible system. It was concluded that hydrogen bonding between amide groups of the two polymers enhanced the miscibility.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1984.070290211
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  • 6
    Electronic Resource
    Electronic Resource
    Preparation of syndiotacticity-rich high molecular weight poly(vinyl alcohol) microfibrillar fiber by photoinitiated bulk polymerization and saponification (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 55-67 
    Details
    ISSN: 0887-624X
    Keywords: VPi ; ADMVN ; AIBN ; syndiotacticity-rich HMW PVA ; PVA microfibrillar fiber ; Pn ; saponification ; PVPi ; conversion ; initiation rate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinyl pivalate (VPi) was polymerized in bulk by ultraviolet-ray initiation at low temperatures using 2,2′-azobis(2,4-dimethylvaleronitrile) (ADMVN) and 2,2'-azobis(isobutyronitrile) (AIBN) as photoinitiators. High molecular weight (HMW) poly(vinyl pivalate) (PVPi), having a number-average degree of polymerization (Pn) of 13,000-28,000, was obtained at conversions below 30% and converted by saponification to a syndiotacticity-rich HMW poly(vinyl alcohol) (PVA) microfibrillar fiber with Pn of 7300-18,300, syndiotactic diad (S-diad) and triad contents of ∼ 64% and ∼ 39%, respectively, and crystal melting temperature (Tm) of ∼ 249°C. ADMVN gave higher Pn than AIBN. On the other hand, conversion was smaller with the former than with the latter, and it was found that the initiation rate of ADMVN was lower than that of AIBN. Pn of PVA was constant while Pn of the precursor PVPi increased with increasing conversion. The syndiotacticity, Tm and thermal stability of PVA obtained from PVPi were much superior to those of PVA derived from poly(vinyl acetate) prepared under the same polymerization conditions. Polymerization of VPi at lower temperatures gave PVA with higher syndiotacticity. © 1997 John Wiley & Sons, Inc.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Phase behavior of poly(ether urethane)-nylon 6 block copolymer (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 54 (1994), S. 1997-2011 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Poly(ether urethane) (PEU)-Nylon 6 block copolymer film prepared via melt pressing and subsequent quenching in liquid nitrogen exhibited a one-phase structure due to the specific interaction between urethane groups in the PEU block and the amide groups in Nylon 6 block through hydrogen bonding. Contrary to this, the solvent cast film showed a microphase separated structure which had risen from the poor solubility characteristics of the PEU block in the solvent. However, by heat treatment, the mutual miscibility of the block copolymer increased as a result of the hydrogen bonding formation. The block copolymer and Nylon 6 binary blend showed that these two polymers are compatible over the entire composition range mainly due to the specific interactions between the urethane and the amide groups in the blend through hydrogen bonding. The block copolymer in the ternary blend which consists of polyrethane (PU), Nylon 6, and the block copolymer prepared by melt extrusion was soluble in either of the PU and Nylon 6 homopolymers, inducing a homogenizing effect. © 1994 John Wiley & Sons, Inc.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070541302
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  • 8
    Electronic Resource
    Electronic Resource
    Kinetics of copolycondensation of bis(4-hydroxybutyl) terephthalate and bis(2-hydroxyethyl) terephthalate by ester-interchange reaction (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 62 (1996), S. 473-480 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The kinetics of polycondensation and copolycondensation reactions were investigated using bis(4-hydroxybutyl) terephthalate (BHBT) and bis (2-hydroxyethyl) terephthalate (BHET) as monomers. BHBT was prepared by ester interchange reaction of dimethyl terephthalate and 1,4-butanediol. BHBT and BHET were polymerized at 270°C in the presence of titanium tetrabutoxide (TBT) as a catalyst. Applying second-order kinetics for polycondensation, the rate constants of polycondensation of BHBT and BHET, k11 and k22, were calculated as 3.872 min-1 and 2.238 min-1, respectively. BHBT and BHET were also copolymerized at 270°C using TBT. The rate constants of crossreactions in the copolycondensation of BHBT and BHET, k12 and k21, were obtained by using the results obtained from a proton nuclear magnetic resonance (1H-NMR) spectroscopy and a high-performance liquid chromatography (HPLC). It was found that the rate constants during the copolycondensation of BHBT and BHET at 270°C decreased in the order k21 〉 k11〉 k22 〉 k12 and the monomer reactivity ratio of BHBT was four or five times larger than that of BHET. In calculating the crossreactions, the method by the 1H-NMR spectroscopy gave more accurate results than that by the HPLC. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Monte carlo simulation of copolymerization by ester interchange reaction in miscible polyester blends (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 1637-1645 
    Details
    ISSN: 0887-6266
    Keywords: ester interchange reaction ; Monte Carlo method ; copolymerization ; degree of randomness ; miscible polyester blend ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effects of reaction variables on the degree of randomness in copolymers formed by ester interchange reaction in miscible polyester melt blends were systematically investigated using a Monte Carlo method. Three reaction variables such as the molecular weight difference between two component polymers, the blend ratio, and the reaction ratio of end attack to bond flip, were particularly considered on the cubic lattice model. Ester interchange reactions were assumed to take place during reptational chain motions. It was found that the copolymerization was dependent upon the molecular weight difference and reaction ratio: As the molecular weight difference becomes smaller and when both end attack and bond flip reactions are involved simultaneously, the copolymerization is accelerated. However, the blend ratio does not affect the copolymerization process. This result is discussed in relation to the polymer chain conformation for the ester interchange reaction. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1637-1645, 1998
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Insoluble polyelectrolyte complex formed from chitosan and α-keratose: conformational change of α-keratose (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 2175-2183 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The conformational change of α-keratose in the polyelectrolyte complex (PEC) formation with chitosan was investigated by means of differential scanning calorimetry and infrared spectroscopy. The change of the secondary structure of α-keratose in the reaction mixture was estimated quantitatively with circular dichroic spectra by the curve fitting method. The α-helix structure of 30% and above of α-keratose was found to be destructed and transformed into random structures at a mixing ratio of maximum PEC formation.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1996.021970709
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