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Mean-square radius of gyration of polysiloxanes

โœ Scribed by Zhiping Zhou; Deyue Yan


Publisher
John Wiley and Sons
Year
1997
Tongue
English
Weight
327 KB
Volume
6
Category
Article
ISSN
1022-1344

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โœฆ Synopsis


Abstract

The meanโ€square radius of gyration for polysiloxanes has been derived according to the exact definition. Taking account of the examples of symmetrically substituted poly(dimethylsiloxane) and unsymmetrically substituted poly(methylphenylsiloxane), we find that the dependence of ใ€ˆS^2^ใ€‰ on the molecular weight follows the general formula ใ€ˆS^2^ใ€‰ = aM^b^ with b = 1 ยฑ 0.016, which is analogous to the theoretical outcomes for vinyl or vinylidene polymers even though the skeletal bone of polysiloxanes consists of alternating heteroatoms. A numerical comparison of the rigorous expression of the meanโ€square radius of gyration given in this paper with that reported by Flory shows that the difference is obvious for lowโ€molecularโ€weight polymer and it gradually declines with increasing degree of polymerization.


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