THE UTILITY OF 2-NAPHTHOL DERIVATIVES AS DIELS-ALDER BASED CO-REACTANTS FOR BISMALEIMIDES

A number of 2-naphthols were found to undergo a Diels-Alder addition r eaction with maleimides. This reaction can be used to bring about the cure of bismaleimides. The simplest co-reactant prepared in this work was 7-allyloxy-2-naphthol and satisfactory cures were obtained with ap propriate bismaleimides. However, the laminate coupons made using this system had lower thermal stability than those of a comparable system using the commercial co-reactant Matrimid 5292B. The performance of th is new chemistry was further tested by incorporating the naphthol/male imide Diels-Alder addition structure into two other co-reactants. The most successful of these compounds (the diallyl ether of the adduct ma de from Diels-Alder addition of 2,7-dihydroxynaphthalene and 4-hydroxy phenylmaleimide) produced cured neat resin samples having T(g)s 30 deg rees C higher than those of a comparable system cured with the standar d bismaleimide co-reactant (Matrimid B) and had slightly higher tensil e strength and modulus than this system. The fact that these laminate coupons had better thermal performance than the system using commercia l co-reactant showed that the presence of the Diels-Alder adduct struc ture in the resin backbone was not detrimental to the normal performan ce of ene cured bismaleimides. On the other hand the same structure in corporated into phenylethynyl end-capped resins was found to compromis e its thermal stability.