Abstract
Glass fiber reinforced plastics (GFRP) are extensively used in many kinds of industrial fields. Matrices commonly used for GFRP are unsaturated polyester, epoxy, and phenolic resins. Especially expected are phenolic resins because of their good heat and flame resistance, and high mechanical properties. The objective of this study is to develop a new type of high-performance phenolic GFRP which needs no catalysts and releases no volatiles in the curing process.
Bisphenol-A type novolac based benzoxazine (BisAN-a), as a new type phenolic resin precursor, was prepared from bisphenol-A type novolac, formaline and aniline. Matrix used was a molten mixture from BisAN-a and bisoxazoline. Bisoxazoline is a well known compound for improving the interfacial bond strength between the matrix and fibers. GFRP laminate was prepared by hand lay-up method using E-glass woven fabric (cloth) of 10 plies, the fiber surface of which had been treated with an acrylic silane. As a result, GFRP from BisAN-a and bisoxazoline showed higher heat resistance, tensile strength, flexural strength, and especially impact strength than GFRP from a conventional bisphenol-A type novolac (BisAN) and bisoxazoline. The reason for getting such high performances with the former laminate was considered as follows : the interfacial bond strength of the former was slightly weaker than that of the latter, and so much stress concentration would not build up in the matrix due to relaxation caused by interfacial partial delamination.
