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  • 1
    Digitale Medien
    Digitale Medien
    Synthesis and dielectric analysis of aliphatic poly(carbonate-sulfone)s based on 1,4-bis(3-hydroxypropylsulfonyl) butane (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2809-2816 
    Details
    ISSN: 0887-624X
    Schlagwort(e): 1,4-bis((3-hydroxypropylsulfonyl)butane ; polycarbonate ; poly(carbonatesulfone) ; liquid crystalline ; dipole-dipole interaction ; dielectric constant ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: High molecular weight aliphatic poly(carbonate-sulfone) homopolymer (PC-343) and random copolymer (PC-343-10) were synthesized from 1,4-bis(3-hydroxypropylsulfonyl)butane (Diol-343) and a 1/1 molar mixture of Diol-343 and 1,10-decanediol, respectively. As a comparison, an aliphatic polycarbonate homopolymer (PC-10) was prepared from 1,10-decanediol. While PC-10 exhibited a single melting peak during its DSC heating scan, both PC-343 and PC-343-10 exhibited multiple reproducible first-order transitions during DSC heating scans. Both PC-343 and PC-343-10 showed broad reflections in their WAXD diagrams; the crystalline order of PC-343 is higher than that of PC-343-10. Based on the DSC and WAXD results and our discovery on the liquid crystalline behavior of aliphatic poly(carbonate-sulfone)s from 1,3-bis(hydroxypropylsulfonyl)propane, we suggest PC-343 and PC-343-10 are liquid crystalline and the liquid crystalline phase formation is directed by the dipole-dipole interactions between sulfone groups. Films were obtained from these polymers by compression molding and dielectric analyses were conducted on them. One glass transition related dielectric relaxation was observed in PC-343-10. One glass transition related dielectric relaxation and one sub-glass transition related dielectric relaxation were observed in PC-343. The glass transition temperature increases with the increase of sulfone content in the polymers. A dramatic rise in dielectric constant with temperature was observed in PC-343 and PC-343-10 at low frequencies, which is probably due to the sulfone dipole interaction with the electrical field. © 1994 John Wiley & Sons, Inc.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1994.080321502
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  • 2
    Digitale Medien
    Digitale Medien
    Dipole-dipole interaction directed liquid crystalline polymers. I. Aliphatic poly(carbonate-sulfone)s based on 1,3-bis(3-hydroxypropylsulfonyl)propane (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2291-2300 
    Details
    ISSN: 0887-624X
    Schlagwort(e): polycarbonate ; polysulfone ; liquid crystal ; 1,3-bis(3-hydroxypropyl sulfonyl) propane ; smectic ; X-ray ; dipole-dipole interaction ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Aliphatic poly(carbonate-sulfone) homo- and copolymers were prepared from 1,3-bis(3-hydroxypropylsulfonyl)propane (Diol-333) and various alkanediols. The copolymers are random in nature since they were prepared by melt copolymerization. Both the homopolymer and the copolymers exhibited multiple reproducible first-order transitions during differential scanning calorimetry (DSC) heating scans, but most of them exhibited only single exotherm during cooling scans. Typical schlieren textures were observed when these polymers were cooled from their isotropic melts. The copolymers have wide-angle x-ray diffraction (WAXD) patterns almost identical to that of the homopolymer except in the low-angle spacing, indicating their packing in the crystalline domain in similar. DSC, cross-polarized optical microscopy, and WAXD revealed that these polymers were smectic liquid crystalline at room temperature. Since aliphatic poly(carbonate-sulfone)s are flexible linear polymers with no rigid rod components, the liquid crystalline phase formation is probably directed by the dipole-dipole interactions between sulfone groups in adjacent chains. © 1994 John Wiley & Sons, Inc.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1994.080321211
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  • 3
    Digitale Medien
    Digitale Medien
    Sorption and diffusion of alcohols in amorphous polymers (1981)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 21 (1981), S. 542-547 
    Details
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The effects of polymer composition and penetrant molecular size on the solubility and diffusivity of alcohol vapors in a series of well characterized isoprene-methyl methacrylate copolymers and their corresponding homopolymers has been investigated at room temperature. The rate of sorption behavior changes progressively from Fickian to non-Fickian, to Case II to “Super Case II” transport with increasing methyl methacrylate (MMA) content in the polymers. The equilibrium solubility of the alcohols increases linearly with increasing penetrant molecular size for polymers which are above their glass transition temperature and decreases for polymers which are below their Tg. The solubility also initially increases as an approximately linear function of MMA content in the copolymers. At about 55 mole percent MMA, the sorbed concentration either levels off or passes through a maximum depending on the size of the penetrant. The apparent “diffusion coefficients” (D) decrease with increasing molecular volume of the penetrants. An exponential dependence was found between these two variables for PMMA. These “diffusion coefficients” also decrease exponentially with increasing MMA content in these polymers. However, at 55 mole percent MMA the copolymer undergoes a rubber to glass transition at the temperature of the experiments. On this basis, it is suggested that the hindered chain segmental motion contributes to the sorption process in addition to strictly thermodynamic considerations. Free volume theory can be used to explain the mechanism of diffusion through the rubbery polymers while the “hole” theory can be applied to explain the transport of the penetrants through the glassy polymers.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pen.760210906
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  • 4
    Digitale Medien
    Digitale Medien
    Stress-Cracking of high density polyethylene in detergents (1987)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 82-85 
    Details
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Correlations of the stress intensity factor, KI, with crack speed, ċ, have been obtained in a number of detergent solutions each having different detergent concentration. A constant crack speed region was observed in high density polyethylene. The KI independent constant crack speed was found to vary linearly with detergent concentration. The viscosity of the detergent solution increases with concentration and hence this region is not controlled by the hydrodynamic properties of the environment in contrast with Williams' model. The KI-ċ data were compared with existing models of crack propagation.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pen.760270112
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  • 5
    Digitale Medien
    Digitale Medien
    The effect of fusion and physical aging on the toughness of poly(vinyl chloride) (1986)
    Brookfield, Conn. : Wiley-Blackwell
    Journal of Vinyl and Additive Technology 8 (1986), S. 183-188 
    Details
    ISSN: 0193-7197
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: It is well known that during aging or annealing, materials become stiffer and more brittle, and creep and stress relaxation rates decrease. Research in this area is very important because physical aging (annealing) plays a large role in the production of products, and it also occurs during the use of the objects or products. The decrease of free volume with time is unavoidable even at ambient temperatures. The influence of fusion and physical aging on the toughness of extruded PVC profiles was investigated. It is known that the toughness of PVC is influenced by secondary crystallization - after primary particles of PVC are partially melted. Recrystallization upon cooling or annealing forms a three-dimensional structure tying together the primary particles. This three-dimensional structure normally produces a tougher PVC product. The density of glassy PVC can be changed by changing the quenching rate. The density can be further changed by annealing below Tg. The densification of a glassy polymer normally leads to a less tough PVC product. This study uses density measurements and differential scanning calorimetry scans to measure the amount of enthalpy relaxation (related to densification) and crystalline melting energy (related to the amount of crystallinity) for various annealed samples. These are related to toughness as measured by notched Izod and droppeddart impact tests.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/vnl.730080411
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