A novel
methacrylic-based R-transmer,
named 2-(methacryloyloxy)ethyl
4-cyano-4-(((propylthio)carbonothioyl)thio)pentanoate, was synthesized,
and its reactivity (propagation versus reversible chain transfer)
in reversible addition–fragmentation chain transfer self-condensing
vinyl polymerization (RAFT-SCVP) with methyl methacrylate (MMA) was
studied to apprehend its impact on hyperbranched polymers (HBP) structure.
The resulting HBP were characterized by nuclear magnetic resonance
(NMR) spectroscopy, size exclusion chromatography (SEC) and differential
scanning calorimetry (DSC) to determine, respectively, their composition
and degree of branching (DB), number average molecular weight (Mn
) and dispersity (Đ),
and glass transition temperature (T
g).
Homopolymers of methacrylic-based R-transmer and copolymers with MMA
were considered to study the reactivity of the methacrylic-based R-transmer
with different initial molar ratios [MMA]0/[R-transmer]0 through kinetic studies and its consequences on HBP macromolecular
characteristics and thermal properties. By varying the [MMA]0/[R-transmer]0 ratio from 1:1 to 100:1, HBP with increasing Mn
(from 6,400 to 14,900 g mol–1) and T
g values (from 36.1 to 87.9 °C),
decreasing Đ values (from 4.07 to 1.71) and
DB values (from 0.30 to 0.03) were obtained.