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Mean‐square radius of gyration of polysiloxanes
Author(s) -
Zhou Zhiping,
Yan Deyue
Publication year - 1997
Publication title -
macromolecular theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 56
eISSN - 1521-3919
pISSN - 1022-1344
DOI - 10.1002/mats.1997.040060111
Subject(s) - radius of gyration , gyration , degree of polymerization , polymer chemistry , mean square , heteroatom , polymer , radius , polymerization , square (algebra) , materials science , polymer science , chemistry , thermodynamics , mathematics , physics , organic chemistry , geometry , composite material , mathematical analysis , computer security , computer science , ring (chemistry)
The mean‐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 〈 S 2 〉 on the molecular weight follows the general formula 〈 S 2 〉 = aM b with b = 1 ± 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 mean‐square radius of gyration given in this paper with that reported by Flory shows that the difference is obvious for low‐molecular‐weight polymer and it gradually declines with increasing degree of polymerization.