FORMATION OF HOMOGENEOUSLY BRANCHED POLYMERS USING TERMINAL DOUBLE-BOND POLYMERIZATION

A method of synthesizing homogeneously branched polymers using long-ch ain branching through terminal double bond polymerization is considere d theoretically. It was found that the homogeneously branched polymers can be obtained by conducting polymerizations that involve both creat ion and dissipation of terminal double bonds in a continuous stirred-t ank reactor (CSTR). Because the analytical expressions for the full mo lecular weight distribution (MWD) as well as the fractional MWDs conta ining 0, 1, 2, etc., branch points can be determined, such polymer mol ecules are regarded as polymers with a well defined branched structure . When the same polymerization reactions are conducted in a batch reac tor, or in a CSTR operated under non-steady state, the homogeneous str ucture cannot be formed. The heterogeneity in the distribution of bran ch points can make the weight-average molecular weight larger or small er compared with the homogeneously branched polymers, depending on the branching density distribution even at the same average branching den sity level. (C) 1997 Elsevier Science Ltd.