Investigation of the mechanical properties of the modified poly(p-phenylene benzobisoxazole) fibers based on 2-(4-aminophenyl)-1H-benzimidazol-5-amine

A simple and efficient route preparing the carbon nanotube/2-(4-aminophenyl)-1H-benzimidazol-5-amine/poly(p-phenylene benzobisoxazole) (CNT-APBIA-PBO) copolymer was introduced in this article. The processability and mechanical properties were improved significantly after the incorporation of APBIA. First, the APBIA was prepared by ring-closure condensation and hydrogenation reduction from 4-nitrobenzaldehyde and 4-nitro-1,2-phenylenediamine. Then, the CNT-APBIA-PBO copolymer was prepared via copolymerization. After that, continuous CNT-APBIA-PBO copolymer fibers were fabricated using a dry-jet wet-spinning technique. The prepared CNT-APBIA-PBO copolymer fiber was characterized by Fourier transform infrared, wide-angle X-ray diffraction, and ¹³C nuclear magnetic resonance spectroscopy, and its microstructure was analyzed by atomic force microscope and scanning electron microscope, respectively. The results show that CNT-APBIA-PBO copolymer fibers have a super thermal resistance similar to PBO, a tensile modulus about 34.9% higher than that of PBO fibers within a 30.4% enhancement of the tensile strength.