The thermal behavior and physical structure of atactic poly(methyl-n-propylsilane) (PMPrS) have been investigated by complementary techniques. Temperature-dependent wide-angle X-ray scattering as well as thermal analysis clearly indicate that atactic PMPrS crystallizes below 40ะC in a monoclinic lat
UV, Raman and XRD study of polymorphism of poly(methyl-n-propylsilane)
โ Scribed by Sergey S. Bukalov; Yan V. Zubavichus; Larissa A. Leites; Julian R. Koe; Robert West
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 858 KB
- Volume
- 50
- Category
- Article
- ISSN
- 0032-3861
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โฆ Synopsis
Raman, UV and XRD studies have been performed to characterize the structures of differently prepared samples of poly(methyl-n-propylsilane). The results demonstrate polymorphism of this polymer between T c and T g . At room temperature the polymer can exist in up to four modifications which comprise one amorphous disordered phase and three more ordered modifications, differing in the interchain organization and in the silicon backbone conformations. The latter are considered to be deviant, transoid and allanti, respectively. The number of the modifications present and relative amount of each strongly depends on the preparation method and thermal history of the sample as well as on the molecular weight.
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a b s t r a c t Poly(N-vinylpyrrolidone) (PVP) hydrogels have become increasingly important materials for pharmaceutical and biomedical applications. UV-light initiated oxidative crosslinking of PVP represents a novel method for producing PVP based hydrogel materials. However, the mechanism of the g