## Abstract The calculations of the meanโsquare radius of gyration for more than thirty sorts of polymer chains are reviewed on the basis of a unified approach. A general expression of the meanโsquare radius of gyration was developed for polymer chains with side groups and/or heteroatoms. It consis
Mean-square radius of gyration of polysiloxanes
โ 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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โฆ Synopsis
Abstract
The meanโsquare 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 ใS^2^ใ on the molecular weight follows the general formula ใS^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 meanโsquare radius of gyration given in this paper with that reported by Flory shows that the difference is obvious for lowโmolecularโweight polymer and it gradually declines with increasing degree of polymerization.
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