Oxygen plasma processing and improved interfacial adhesion in PBO fiber reinforced epoxy composites

The effects of oxygen plasma processing on the improved interfacial adhesion properties of poly(1,4-phenylene-cis-benzobisoxazole) (PBO) fiber reinforced epoxy composites have been investigated in this paper. Both As-spun (AS) and high-modulus (HM) PBO fiber systems were studied. The characterization techniques included microscopy, surface analysis, and composite interfacial adhesion tests. The results showed that the high-modulus fiber surface free energy could be increased significantly by 42.2% from 46.2 to 65.7 mJ/m(2), while the tensile strength was only slightly decreased by 3.4% from 5.87 to 5.67 GPa. the interfacial adhesion strength of PBO fiber reinforced epoxy composite was improved by In addition, 37.5% from 32.5 to 44.7 MPa for the HM fiber system. The improvement has been attributed to the enhanced cohesive failure that dissipated more fracture energy. (c) 2009 Elsevier Ltd. All rights reserved.