Investigation of the processability, thermal, mechanical and flame retardant properties of bisoxazoline composites*

Presented here is an investigation into the cure kinetics, thermal and mechanical properties, and fire resistance of a carbon fibre composite using a polymer matrix blend composed of 1,3 phenylene bisoxazoline, a phenolic resin and dodecylbenzene sulfonic acid. This polymer matrix is further modified with a benzoxazine, a tetra-functional epoxy amine resin and the engineering thermoplastic, polyether sulfone (PES) to explore their effect on the reaction mechanism and final properties of the composite after cure and post-cure. The modifiers reduce the reactivity of polymerisation and the final glass transition temperature of the network as shown by the rate constants, determined from the Kissinger and Sestak-Berggren models. Subsequent post-curing of the composite increases the glass transition temperature, thermal stability, interlaminar shear strength, and fire performance as determined by UL-94 vertical burn test. Ensuring the network is fully cured is clearly critical to optimum performance of the composite. The high char yields of the bisoxazoline polymer networks, particularly after postcure illustrate great potential for applications where high temperature resistance is required.

Automated summary

This study investigates the cure kinetics, thermal and mechanical properties, and fire resistance of a carbon fibre composite with a polymer matrix blend. The addition of modifiers in the matrix affects the reaction mechanism and final properties of the composite. Post-curing improves the performance of the composite, particularly in terms of fire resistance.