Mechanical and Dynamic Mechanical Analysis of PBO Paper-based Composites

Poly ( p-phenylene benzoisoxazole; PBO) paper is a potential raw material for use in honeycomb sandwich composites in the aerospace industry, which are able to sustain high temperatures exceeding 300°C. This work presents a wet-forming method of making PBO paper, consisting of PBO chopped fibers. The paper was impregnated with phenolic resin to simulate honeycomb wall material. The structure and mechanical and dynamic mechanical properties of the raw and impregnated paper were characterized. The performance of PBO paper was tested against p-aramid paper. The comparative results showed the tensile strength of PBO raw paper was 2.17 kN/m, which was slightly worse than p-aramid raw paper: 2.66 kN/m. After impregnation, the tensile strength of the PBO paper was 13.93 kN/m due to the increase in the number of bonding points—better than p-aramid paper: 7.99 kN/m. The tearing resistance value for PBO raw paper versus p-aramid raw paper was 3252 mN against 845 mN. The morphology of the torn samples in the impregnated paper revealed higher levels of PBO fiber pullout than p-aramid fiber, therefore the tearing resistance value was 6000 mN for PBO impregnated paper, which was again superior to p-aramid impregnated paper: 675 mN. The PBO paper also showed higher storage modulus than p-aramid paper after impregnation. Experimental studies showed that PBO paper could be used in load-bearing structures and in honeycomb components where high resistance to deformation and thermal stability is necessary.