The number average and mass average molar masses of polyethylene(propylene)glycol fumarates

Abstract

Unsaturated polyesters are interesting for theoretical and practical studies, since along with the simplicity of economical production, contain in their composition unsaturated double bonds, which makes it possible to obtain spatially crosslinked structures on their basis. In this work polyethylene glycol fumarate, polypropylene glycol fumarate were synthesized by the step-growth polymerization of ethylene(propylene)glycol and fumaric acid. The compositions of polyethylene(propylene)glycol fumarates were determined using elemental analysis and IR spectroscopy. Some physicochemical characteristics of synthesized polyethylene(propylene)- glycol fumarates were established. In order to state the correlation between the molar masses of polyethylene( propylene)glycol fumarates, the number average and mass average molar masses were found. As follows from the results presented in this paper mass average molecular masses of polyethylene glycol fumarate and polypropylene glycol fumarate calculated by the light scattering were around 2500 and 1488 a.e.m., the number average molar masses determined by the method of end groups were 2010 and 1245 a.e.m., respectively. It is shown that the methods of light scattering and end-group assay give good convergence and have a high degree of correlation. As a result of the study the correctness the light scattering method for the estimation of molecular masses of polyethylene(propylene)glycol fumarates was shown.