Rigid Hyperbranched Polycarbonate Polyols from CO₂ and Cyclohexene-Based Epoxides

Abstract

Hyperbranched, multifunctional polycarbonate polyols based on CO2, cyclohexene oxide (CHO), and the “inimer” (initiator–monomer) (4-hydroxymethyl)­cyclohexene oxide (HCHO) were prepared in one-pot syntheses. The related linear poly­(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 CO2/epoxide polymerizations were catalyzed by the (R,R)-(salcy)-Co­(III)­Cl 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–1 and moderate dispersity between 1.18 and 1.64 (M w/M n) 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 cm3 g–1 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.

Aluminum-Based Initiators from Thiols for Epoxide Polymerizations

“…Polyethers are important industrial polymers where they are used in the production polyurethanes , and are found in common consumer products such as laxatives, eye drops, medicines, and lubricants, as well as in the technological applications such as lithium-ion batteries, separation membranes, , antifouling coatings, , and biomedical applications . The ubiquity and utility of polyether materials are the results of their functional monomer precursors, epoxides.…”

“…Thio-aluminum initiators (SAls) can be easily synthesized from the reaction of a thiol-containing ligand and trimethylaluminum. The kinetic and molecular weight control of epoxide polymerizations initiated by SAls was investigated by tuning the catalyst concentration and monomer to initiator ratio and characterized by 1 H NMR spectroscopy and size-exclusion chromatography (SEC). Initiator chemistry was varied to investigate polymer end group control as well as the effect on polymerization kinetics.…”

Orthogonal functionalization of alternating polyesters: selective patterning of (AB)n sequences

“…The increase in T g is attributed to inter-/intra-chain hydrogen bonding, a phenomenon which is common in biopolymers and has been observed for other hydroxyl-functionalized polymers. 62,63 The entire series of alternating functionalized polymers (P1(b)-P1(f)) show lower T g values (À8 C to 86 C) than P1(a) probably due to the increased hydrodynamic volumes (Fig. S28 †).…”

Functional Polycarbonates from Carbon Dioxide and Tailored Epoxide Monomers: Degradable Materials and Their Application Potential

“…Adjustable T g s between 72 and 105 °C and low intrinsic viscosities down to 5.69 cm 3 g −1 in DMF were obtained for the hyperbranched structures. The linear analogues showed T g values between 113 and 141 °C …”