The structure buildup in hyperbranched polyesters from 2,2-bis(hydroxymethy
l)propionic acid (bis-MPA) was studied experimentally. Bis-MPA and its dend
ritic trimer were both polymerized in bulk using acid catalyst. The fractio
ns of terminal, dendritic, and linear repeating units were monitored by C-1
3 NMR during the course of reaction. Effect of slow monomer addition on the
degree of branching in the final product was also studied. Hyperbranched p
olymers from bis-MPA with and without a core molecule were kept at the poly
merization temperature in order to examine the effect of heat treatment on
composition in the polymer. The fractions of the different repeating units
were changing to a large extent with conversion. Slow monomer addition to a
trifunctional core molecule gave a product with a degree of branching of 4
7%. Heat treatment of hyperbranched materials gave small changes in the fra
ctions of the different repeating units in both materials and, eventually,
gelling in the material without a core.