Propylene Oxide and Higher 1,2‐Epoxide Polymers

Abstract

Polymeric derivatives of propylene oxide (PO) and higher epoxides are very important in polymer chemistry. Low molecular weight homopolymers of PO and copolymers of PO and ethylene oxide are used in polyurethanes, hydraulic fluids, lubricants, surface active agents, and chemical intermediates. They are known as polyether polyols, polyethers, or polyols. Low molecular weight polyethers are prepared via acid or base catalysis. Propylene oxide is manufactured by either the chlorohydrin process or the peroxidation process. Polymerization mechanisms (anionic, cationic, and coordinate) are described. Details of polyol manufacture are given, such as stoichiometry, processing, removal of catalyst, and stabilization, for example. The most important chemical property of poly(propylene oxide) in polyurethane applications is the primary or secondary hydroxyl end group. Properties of various polyols are given. A number of block and random copolymers are known. Propylene oxide is highly reactive and is a primary irritant. Toxicities of selected epoxides are given.

Hyperbranched Polyols via Copolymerization of 1,2-Butylene Oxide and Glycidol: Comparison of Batch Synthesis and Slow Monomer Addition

“…SEC (calibrated with linear PEG standards) revealed rather low apparent molecular weights in the range of 900 to 1300 g mol –1 and mostly monomodal, moderate distributions with Đ ranging from 1.41 to 1.65. The molecular weight limiting chain transfer reaction was observed for hyperbranched poly­(ethylene oxide) and poly­(propylene oxide) copolymers before. , There are, however, clearly no signs of chain transfer by proton abstraction at the α-methylene group of the BO monomer, which is commonly observed during anionic homopolymerization of 1,2-butylene oxide . In this case, unsaturated chain ends would be found in the NMR spectra, which is not the case.…”

“…37,38 There are, however, clearly no signs of chain transfer by proton abstraction at the α-methylene group of the BO monomer, which is commonly observed during anionic homopolymerization of 1,2-butylene oxide. 41 In this case, unsaturated chain ends would be found in the NMR spectra, which is not the case.…”

Ring‐Opening Polymerization

“…Excluding polymerizations with anionic coordination initiators, the polymer molecular weights are low for anionic polymerizations of propylene oxide (<6000) [Clinton and Matlock, 1986;Boileau, 1989;Gagnon, 1986;Ishii and Sakai, 1969;Sepulchre et al, 1979]. Polymerization is severely limited by chain transfer to monomer.…”

“…Polymerizations and copolymerizations of ethylene and propylene oxides as well as polymerization of tetrahydrofuran are used to produce polyether macrodiols, specifically, telechelic polyethers having hydroxyl end groups [Clinton and Matlock, 1986;Gagnon, 1986]. The commercial materials are typically in the molecular weight range 500-6000 and are used to produce polyurethane and polyester block copolymers, including the thermoplastic polyurethane and polyester elastomers (Secs.…”

Real‐time FTIR monitoring of the mechanism of initiation of isobutylene polymerizations by epoxide/Lewis acid systems

“…The mechanism of the cationic polymerization of epoxides yielding low‐molecular‐weight polyethers had not been clear; some researchers suggested carbocation involvement via S N 1 mechanism, while others claimed S N 2 mechanism via oxonium ions 7. On the basis of the results of real‐time FTIR monitoring of the initiation and propagation of IB polymerization by the TMPO‐1/TiCl 4 system, we proposed competitive occurrence of both S N 1 and S N 2 pathways 1, 2.…”