Two-Component initiator systems for the ring-opening polymerization of oligomeric cyclic bisphenol-A carbonates. Studies with in situ generated wittig salts

✍ Scribed by Herman O. Krabbenhoft

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 590 KB
• Volume: 61
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19960808)61:6<1017::aid-app16>3.0.co;2-t

✦ Synopsis

A two-component initiator system based on the in situ generation of Wittig salts (alkytriarylphosphonium bromides) has been developed for the ring-opening polymerization of cyclic bisphenol-A (BPA) carbonate oligomers for potential use in composite applications so that the prepolymer can suitably wet the composite material before being converted to high molecular weight polymer. The Wittig salt precursors (an alkyl bromide, such as hexadecyl bromide, and a triarylphosphine, such as triphenylphosphine) did not independently initiate significant ring-opening polymerization of the oligomeric cyclic BPA carbonate mixture. However, when the two mixtures of cyclic BPA carbonate oligomers and initiator component were combined, a high molecular weight polymer (Mu = -65,000) was produced. The polymerization initiating species is thought to be hexadecyltriphenylphosphonium bromide. Consistent with this hypothesis is the observation that authentic Wittig salts did initiate ring-opening polymerization to provide high molecular weight polycarbonate. The effects of structure and concentration of the initiator components, reaction temperature, time, etc. on polymerization were studied in general, the degree of polymerization ranged from 65 to 85%.