K. Dusek et al., Role of cyclization in the degree-of-polymerization distribution of hyperbranched polymers - Modelling and experiments, POLYM BULL, 42(4), 1999, pp. 489-496
A kinetic model of formation of hyperbranched polymers by step polyaddition
of a BA(f) monomer including cyclization was developed. Reactions between
acyclic-acyclic and acyclic-cyclic molecules and cyclization within acyclic
molecules were considered. For cyclization within isomers of an x-mer, a b
ridging function between linear and spherical structures was used. Fraction
s of cyclic x-mers are predicted to increase with increasing degree of poly
merization a: and overall conversion of B groups. High fractions of cyclics
were found in poly[2,2-bis(hydroxymethyl)propanoic acid] (poly(dimethylolp
ropionic acid)) by mass spectroscopy (ESI/FT MS) in a reasonable agreement
with the model.