Significant improved interfacial properties of PBO fibers composites by in-situ constructing rigid dendritic polymers on fiber surface

In this study, the interfacial properties of PBO fiber were enhanced significantly through constructing the rigid dendritic polymers on its surface. The rigid branched structure and massive functional groups of dendritic polymers endowed the interphase with more powerful physical entanglement and mechanical interlocking, abundant chemical bonding, improved interfacial compatibility and moderate mechanical properties. Compared with untreated PBO fiber composites, the interfacial shear strength and interlaminar shear strength of modified PBO fiber (PBO-M2) composites increased by 81.49 and 42.17%, respectively. Meanwhile, the impact strength raised from 68.15 to 103.28 kJ/m 2 due to the construction of rigid dendritic polymers. Dynamic mechanical evaluation also indicated that the storage modulus (at 30 °C) of PBO-M2 composites increased from 34 ± 2 to 47 ± 3 GPa. Moreover, the hydrothermal aging resistance of PBO-M2 composites was also markedly improved.