Blends of unsaturated polyester and phenolic resins for application as fire-resistant matrices in fibre-reinforced composites. Part 1: identifying compatible, co-curable resin mixtures

An unsaturated polyester resin, cured with styrene of commercial origin, has been blended and cured with several commercial phenolic resoles with a view to obtain a homogeneous polymer blend having better fire resistance than unsaturated polyester alone. It is shown that blends of the unsaturated polyester with an allylically modified resole are not only physically compatible (miscible), but also chemically compatible in which they co-cure to an extent to give, probably, a co-continuous interpenetrating polymer network.