1 research outputs found
Rigid Hyperbranched Polycarbonate Polyols from CO<sub>2</sub> and Cyclohexene-Based Epoxides
Hyperbranched,
multifunctional polycarbonate polyols based on CO<sub>2</sub>, cyclohexene
oxide (CHO), and the “inimer”
(initiator–monomer) (4-hydroxymethyl)Âcyclohexene oxide
(HCHO) were prepared in one-pot syntheses. The related linear polyÂ(hydroxymethyl
cyclohexene carbonate) structures based on protected HCHO and postpolymerization
deprotection were also synthesized as model compounds. The content
of hydroxyl functionalities was adjustable for both linear and hyperbranched
terpolymer systems. All CO<sub>2</sub>/epoxide polymerizations were
catalyzed by the (<i>R</i>,<i>R</i>)-(salcy)-CoÂ(III)ÂCl
complex. The polycarbonates obtained were comprehensively investigated
using various 1D and 2D NMR techniques, SEC, FT-IR, UV–vis
spectroscopy, and contact angle measurements. Rigid polyols with molecular
weights between 3600 and 9200 g mol<sup>–1</sup> and moderate
dispersity between 1.18 and 1.64 (<i>M</i><sub>w</sub>/<i>M</i><sub>n</sub>) were obtained. In addition, the materials
were examined with respect to their thermal properties, intrinsic
viscosity, and their three-dimensional structure. Glass transition
temperatures in the range of 113–141 °C (linear) and 72–105
°C (hyperbranched) were observed. The intrinsic viscosity of
the hyperbranched systems is in the range of 5.69–11.51 cm<sup>3</sup> g<sup>–1</sup> and mirrors their compact structure.
The hyperbranched polyols were also studied regarding their successful
reaction with phenyl isocyanate to convert the free hydroxyl groups
into urethanes