DEVELOPMENT OF A NEW ADVANCED PROCESS FOR MANUFACTURING POLYACETAL RESINS .3. END-CAPPING DURING POLYMERIZATION FOR MANUFACTURING ACETAL HOMOPOLYMER AND COPOLYMER
J. Masamoto et al., DEVELOPMENT OF A NEW ADVANCED PROCESS FOR MANUFACTURING POLYACETAL RESINS .3. END-CAPPING DURING POLYMERIZATION FOR MANUFACTURING ACETAL HOMOPOLYMER AND COPOLYMER, Journal of applied polymer science, 50(8), 1993, pp. 1317-1329
Conventionally, acetal homopolymer or copolymer is obtained by the pol
ymerization of formaldehyde or trioxane, following the end-capping usi
ng acetic anhydride or unzipping of the unstable polymer end fraction.
First, Asahi Chemical developed a new process to obtain an end-capped
polymer during polymerization of highly purified formaldehyde using a
cetic anhydride as the chain-transfer agent. Use of highly purified fo
rmaldehyde and end-capping during polymerization using acetic anhydrid
e as a chain-transfer agent or an end-capping agent will provide a sim
ple process for manufacturing acetal homopolymer. The polymerization m
echanism was confirmed by infrared spectroscopy analysis and proton NM
R analysis of the polymer obtained. Second, for the acetal copolymer,
purified trioxane was copolymerized with ethylene oxide in the presenc
e of methylal, which gave an end-capped polymer with high thermal stab
ility. Two new intermediates from the initiation reaction of the copol
ymerization, 1,3,5,7-tetraoxacyclononane (TOCN) and 1,3,5,7,10-pentaox
acyclododecane (POCD), were isolated and a new initiation mechanism wa
s proposed. (c) 1993 John Wiley & Sons, Inc.