EFFECT OF SIDE-GROUP ON MEAN-SQUARE RADIUS OF GYRATION OF ATACTIC POLY(METHYL METHACRYLATE) CHAIN

Taking account of the effect of the large side group, the expression o f the unperturbed mean-square radius of gyration, [S-2], is improved f rom the Lagrange relation. Using the derived relation, the ratio curve , [S-2]/x vs. the logarithm of degree of polymerization x for the atac tic poly(methyl methacrylate) (A-PMMA) chain, gives a small bump, whic h agrees better with experiment data. The characteristic ratio [S-2]/2 xl(2) and the temperature coefficient dIn[S-2]/d T dependence on the s tereoirregularity are also investigated by the derived formula.