In this contribution, the advanced aromatic polymers with excellent antiatomic oxygen (AO) performance were designed and synthesized using molecular precursor strategy and copolymerization of polyhedral oligomeric silsesquioxane (POSS). A soluble poly(p-phenylene benzobisoxazole) (PBO) precursor, that is, TBS–PBO (tert-butyldimethylsilyl was denoted as TBS), was designed to overcome the poor solubility of PBO in organic solvents. Then the new copolymer of TBS–PBO–POSS was synthesized by the copolymerization of TBS–PBO and POSS, which possessed good solubility and film-forming ability in common organic solvents, such as N-methylpyrrolidone, N,N-dimethylacetamide, and dimethyl sulfoxide. More importantly, the TBS–PBO–POSS films exhibited outstanding antiatomic oxygen properties because of the incorporation of POSS monomers with cagelike structure into the main chain of copolymer, which drastically reduced the AO-induced erosion owing to the formation of the passivating silica layer on the surface of polymers. When the TBS–PBO–POSS films were exposed to AO effective fluences of 1.5495 × 1020 atom cm–2 (5 h) and 4.6486 × 1020 atom cm–2 (15 h), the relative mass loss was merely 0.19% and 0.41%, respectively. This work provides a new perspective and efficient strategy for the molecular design of aromatic heterocyclic polymers possessing excellent combination properties including processing convenience and antioxidative and mechanical properties, which can be employed as potential candidates to endure the aggressive environment encountered in low earth orbits.Keywords: aromatic polymers; atomic oxygen; molecular precursor; poly(p-phenylene benzobisoxazole); polyhedral oligomeric silsesquioxnae

The method of “impregnation–winding–lamination–mould pressing” was performed to fabricate novel wave-transparent high modulus poly(p-phenylene-2,6-benzobisoxazole) fibre/bisphenol A cyanate ester resin (HMPBO fibre/BADCy) laminated composites. The “two-step approach” of methanesulfonic acid/γ-glycidoxy propyl trimethoxy silane (MSA/KH-560) was also proposed to functionalize the HMPBO fibres’ surface. Results revealed that KH-560 was grafted on the HMPBO fibres’ surface successfully. The functionalized HMPBO fibre/BADCy laminated composites possessed better ILSS & flexural strength, lower ε & tanδ, and higher heat-resistance index & Tg. The ILSS and flexural strength of the functionalized HMPBO/BADCy laminated composites were increased to 53.7 MPa and 753.7 MPa, respectively. The corresponding ε and tanδ were decreased to 2.93 and 0.00097, respectively. The corresponding heat-resistance index and Tg were increased to 219 °C and 236 °C, respectively. The functionalized HMPBO fibre/BADCy laminated composites display potential application in radomes and the antenna systems of aircrafts.