The use of bisfuroic acid derivatives in the curing of bismaleimides

Preparation and Characterization of Some Novel Bismaleimide Monomers and Polymers Based on Diaminobisimides

New bismaleimide monomers, based on pure diaminobismides (DABIs) have been synthesized. In a number of cases the bismaleimide of the 2:1 (amine/anhydride) DABI adduct has been isolated as a pure compound, but where the starting DABI consisted of a mix of imide oligomers of the diamine and dianhydride (2:1, 3:2 and higher) the corresponding bismaleimide product was found also to have a similar composition ratio. This has been confirmed in one example by separation of the oligomer mix and characterization of the components. The utility of the various bismaleimides as monomers in composite matrices has been assessed by cocuring with the common coreactant, 3,3′-diallylbisphenol A. The physical properties and thermal stability of neat resin samples and laminates are reported as well as some mechanical properties.

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 reaction 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 appropriate 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 this new chemistry was further tested by incorporating the naphthol/maleimide Diels–Alder addition structure into two other co-reactants. The most successful of these compounds (the diallyl ether of the adduct made from Diels–Alder addition of 2, 7-dihydroxynaphthalene and 4-hydroxyphenylmaleimide) produced cured neat resin samples having Tgs 30 °C higher than those of a comparable system cured with the standard bismaleimide co-reactant (Matrimid B) and had slightly higher tensile strength and modulus than this system. The fact that these laminate coupons had better thermal performance than the system using commercial co-reactant showed that the presence of the Diels–Alder adduct structure in the resin backbone was not detrimental to the normal performance of ene cured bismaleimides. On the other hand the same structure incorporated into phenylethynyl end-capped resins was found to compromise its thermal stability.