MOLECULAR WEIGHT AND ALLIED PROPERTIES OF THE POLYMERS

There are many experimental methods to determine the molecular weight of the polymers. The viscosity, sedimentation centrifugation, light scattering and XRD are few experimental methods in vogue. New experimental methods based on dispersion 1 , glass transition temperature are a few developed recently. Though the empirical relation between glass transition temperature and molecular weight is suggested 2 no detailed approach to correlate glass transition temperature with molecular weight is there so far in literature . In present investigation an algebraic relationship is developed correlating the molecular weight ,glass transition temperature, refractive index and density ,since it has been observed that the molecular weight is directly proportional to density, refractive index and inversely proportional to glass transition temperature. Summing up all these concepts an algebraic relation is developed and applied to arrive at molecular weight of few polymers. The polymers taken for this investigation are Poly vinyl Acetate, Poly Vinyl Chloride, Poly Styrene, Poly Methyl Meta Croylite, Poly Vinyl Benzene, Poly Acryolite, Polyvinyl Alcohol, Poly tetra floro ethylene. The data on density, refractive index and glass transition temperature for these samples were taken from references 3,4, 5 and are utilized to arrive at molecular weights. From the data on refractive index ,density and molecular weight the fallowing related physical parameters like optical dielectric constant ,reflection loss , molar refractivity ,electron polarizabulity and inter ionic distance have been evaluated .A study of variation of these evaluated parameters with molecular weight is made .From the study it has been inferred that the reflection loss ,optical dielectric constant and electron polarizabulity vary almost similar fashion with molecular weight .Where as inter-ionic distance and molar refraction shows a distinct variation .A plausible explanation for these physical dependence of the parameters on molecular weight is given and the merits and demerits are discussed thoroughly