Controlled Synthesis of Multi‐Arm Star Polyether–Polycarbonate Polyols Based on Propylene Oxide and CO₂

Abstract

Multi-arm star copolymers based on a hyperbranched poly(propylene oxide) polyether-polyol (hbPPO) as a core and poly(propylene carbonate) (PPC) arms are synthesized in two steps from propylene oxide (PO), a small amount of glycidol and CO2 . The PPC arms are prepared via carbon dioxide (CO2 )/PO copolymerization, using hbPPO as a multifunctional macroinitiator and the (R,R)-(salcy)CoOBzF5 catalyst. Star copolymers with 14 and 28 PPC arms, respectively, and controlled molecular weights in the range of 2700-8800 g mol(-1) are prepared (Mw /Mn = 1.23-1.61). Thermal analysis reveals lowered glass transition temperatures in the range of -8 to 10 °C for the PPC star polymers compared with linear PPC, which is due to the influence of the flexible polyether core. Successful conversion of the terminal hydroxyl groups with phenylisocyanate demonstrates the potential of the polycarbonate polyols for polyurethane synthesis.

CO2-fixation into cyclic and polymeric carbonates: principles and applications

“…In addition to linear poly(carbonate-ether) polyols, starshaped CO 2 -based polyols have also been prepared, via a twostep process starting with the synthesis of a hyper-branched poly( propylene oxide) copolymer with glycerol branching points, which was subsequently used as macro-initiator for the reaction with propylene oxide and CO 2 , generating a polyether core with poly( propylene carbonate) arms. 345 These starshaped structures possess low T g values between −8 and 10°C, due to the flexible polyether core. Other star-shaped CO 2 -based polyols were prepared via the reaction of CO 2 and propylene oxide in the presence of trimesic acid as an initiation-transfer agent, resulting in oligo(carbonate-ether)s with three arms.…”

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

“…Hilf et al described the first example of multiarm star copolymers based on a hyperbranched poly(propylene oxide) polyether‐polyol ( hb PPO) core and PPC arms in two steps from PO, a small amount of glycidol, and CO 2 . The PPC arms were prepared via CO 2 /PO copolymerization, using hb PPO as a multifunctional macroinitiator and the ( R , R )‐(salcy)‐CoOBzF 5 catalyst ( Figure ) . Successful conversion of the terminal hydroxyl groups with phenylisocyanate demonstrates the potential of such polycarbonate polyols for polyurethane synthesis.…”

“…Two‐step synthesis of hyperbranched PPC multiarm star copolymers from PO and CO 2 with hb (PG‐ co ‐PPO) core (left); branching points are generated from glycidol in the first step. Reproduced with permission . Copyright 2014, John Wiley & Sons, Inc.…”

“…Besides the use of functionalized monomers, the properties and functionality of aliphatic polycarbonates can also be controlled by the polymer architecture. The chain transfer reaction including externally added alcohols can be used for the incorporation of specific initiators or the synthesis of various polymer architectures such as block‐ or star‐like copolymers . In this respect, the epoxide/CO 2 copolymerization exhibits features typical of a living polymerization …”

Efficient synthesis of epoxybutane from butanediol via a two-step process

“…2 Until now, the monomer of polyether polyol is mainly chosen from ethylene oxide (EO), propylene oxide (PO) and BO. 3,4 Compared with EO and PO, BO not only possess a similar activity that can react with hydrogen containing compounds, such as water, alcohol, phenols, sulfur alcohol, ammine, acids and so on, but also has unique properties that can improve the durability of diphenylmethane diisocyanate (MDI)-based polyurethane. However, owing to the restrictions from the severe safety issues in the production technology and the expensive cost, the market share of polyether polyol derived from BO is smaller than that made from EO and PO.…”