  Widely available vegetable oils were readily derivatized into chemically pure
ABn-type monomers (n = 2 or 3). Their polymerization led to unprecedented
hyperbranched polyesters. Four different AB2/AB3-type monomers bearing one
A-type methyl ester and two or three B-type alcohol functions were purposely
synthesized via two elementary steps, i.e. epoxidation of the internal double
bond of the vegetable oil precursors followed by ring-opening of the epoxy
groups under acidic conditions. The polycondensation of these bio-sourced
monomers was performed in bulk, in the presence of an appropriate catalyst,
giving access to modular hyperbranched polyesters with tunable properties.
Among the catalysts tested, zinc acetate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene
(TBD) and sodium methoxide proved the most effective, allowing the achievement
of molar masses in the range 3000--10 000 g mol--1 and dispersities varying
from 2 to 15, depending on the initial conditions. The degree of branching, DB,
as determined by 1H NMR spectroscopy, was found to be between 0.07 and 0.45.
The as-devised hyperbranched polyesters displayed either amorphous or
semi-crystalline properties, as a function of the selected AB2/AB3-type initial
monomers, with a glass transition temperature, Tg, ranging from --33 to 9
{\textdegree}C and a decomposition temperature at 5 wt% of the sample, Td5%,
varying from 204 to 340 {\textdegree}C.
