Enhanced mechanical properties and anti-hydrothermal ageing behaviors of unsaturated polyester composites by carbon fibers interfaced with POSS

Trisilanollsobutyl polyhedral oligomeric silsesquioxane (SO 1450 POSS) has been uniformly grafted on the carbon fiber (CF) surface. The surface roughness (108.4 nm) of the CFs grafted with POSS was higher than that of the as-received CFs (57.9 nm). Dynamic contact angle analysis of the SO grafted CFs showed higher surface energy than that of the as-received CFs. After grafted with SO, the interlaminar shear strength of the unsaturated polyester (UPR) composites was 61 MPa, increased by 29.8% compared with that of the composites with the as-received CFs (47 MPa). The interfacial shear strength (IFSS) of SO grafted CFs/UPR composites was 88 MPa, significantly increased by 91% compared with that of the as-received CFs/UPR composites (46 MPa). The IFSS of the SO grafted CFs/UPR composites after hydrothermal ageing was 74 MPa with a decrease of just 16% compared with that of the as-received CFs/UPR composites (30 MPa) with a significant decrease of 35%. The tensile strength of the SO grafted CFs/UPR composites (1280 MPa) was 15% higher than that of the as-received CFs/UPR composites (1110 MPa). The impact energy of 1.52 J for the SO grafted CFs/UPR composites was higher than 1.00 J for the as-received CFs/UPR composites.