Synthesis and ring-opening reactions of tetraphenyl-substituted bisoxazoline monomers for preparing new thermosets and composites

To develop new monomers for formulating thermosetting composites, three new tetraphenyl-substituted bisoxazoline monomers were synthesized via the dir ect reaction of 2-(diphenylmethyl)oxazoline with bromoalkyls, using tert-bu tyllithium. The structures were confirmed by Fourier transform infrared, nu clear magnetic resonance and mass spectrometry. These bisoxazolines have di fferent melting points with varied molecular chain flexibility. They functi oned well as crosslinkers when heated with phenolic resins or poly(acrylic acid), providing a path to new thermosetting materials with controlled glas s transition temperature. To clarify the crosslinking reaction mechanism, t he model reactions of these monomers with phenol and acetic acid were inves tigated. Copyright (C) 2000 John Wiley & Sons, Ltd.