Mechanism of transesterification and cyclization of epoxy–polycarbonate blends catalyzed by quarternary ammonium salt

✍ Scribed by Ming-Shiu Li; Chen-Chi M. Ma; Ming-Shiu Lu; Miaw-Ling Lin; Feng-Chih Chang

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 665 KB
• Volume: 34
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19961130)34:16<3303::aid-pola6>3.0.co;2-u

✦ Synopsis

SYNOPSIS

T h e reaction of oxirane with carbonate using quarternary ammonium salts as catalyst has been studied. Curing is caused by t h e transesterification reaction of the oxirane cycle with t h e carbonate group that proceeds by a n "insertion" mechanism in the stoichiometric system. The ratio of the reactants is two oxirane groups to one carbonate group. I n the nonstoichiometric system, t h e epoxide content is more than the stoichiometric quantity required. A cyclization reaction is followed by the transesterification reaction. T o identify the finished products, a model reaction was proposed using diphenyl carbonate and phenyl glycidyl ether which results in the formation of 4-phenoxymethyl-1,3-dioxolane-2-one (PMD). T h e mechanism of forming the cyclic structure is assumed to proceed through the chain scission of the network in which the molecular chain crosslinked with carbonate group by a transesterification reaction. 0 1996 John Wiley & Sons, Inc.