Calcia-doped ceria hybrid coating functionalized PBO fibers with excellent UV resistance and improved interfacial compatibility with cyanate ester resins

Highlights: • The uniform organic–inorganic hybrid coating is formed on the surface of PBO fibers. • PBO@P-Ce_0.8Ca_0.2O_1.8 fibers present the excellent interfacial bonding strength with resin matrix. • The functionalized PBO fibers coated by the hybrid coating possess excellent UV resistance. Poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers display weak outdoor stability and reliability due to their poor UV resistance and chemically inert surface. In this work, calcia-doped ceria (Ce_0.8Ca_0.2O_1.8) nanoparticles was fabricated via chemical co-precipitation method, and the novel Ce_0.8Ca_0.2O_1.8/P(S-co-BCB-co-MMA) organic–inorganic hybrid coating was then designed and prepared for surface functionalization of PBO fibers (PBO@P-Ce_0.8Ca_0.2O_1.8). Organic-inorganic hybrid coating presents high surface roughness and excellent UV resistance. When the concentration of Ce_0.8Ca_0.2O_1.8 nanoparticles with the particle size of about 50 nm is 0.6 wt%, PBO@P-Ce_0.8Ca_0.2O_1.8–3 fibers (sample 4, 0.6 wt%) present the best interfacial bonding strength with modified bisphenol A cyanate (BADCy) resins, the single fiber pull-out strength between sample 4 and modified BADCy resins reaches the maximum value of 4.6 MPa, 48.4% higher than that of pristine PBO fibers (sample 0, 3.1 MPa). Meanwhile, the tensile strength of sample 4 after 288 h UV aging is increased from 1.4 GPa (PBO fibers) to 4.1 GPa. Overall, functionalized PBO fibers in this work demonstrate higher surface activity, excellent UV resistance and improved interfacial bonding strength with modified BADCy resins, which provides a new idea for functionalizing the surface activity and UV resistance of high-performance polymer fibers.