Enterfacial Properties Of Domestic T700Carbon Fiber Composite

Carbon fiber reinforced resin matrix composites have a wide range of applications because of their excellent performance. Their interfacial properties affect the mechanical performance of composites resulting in the widespread concern. In this paper, the interfacial properties of domestic MT700C carbon fiber and its composite were studied to clarify the relationship among surface composition, micro structure and composites’ interfacial properties, which could provide basic data and theoretical guidance for promoting the use of resin-based composite materials made of domestic MT700C carbon fiber.Domestic MT700C carbon fiber and Toray T700SC carbon fiber were selected to operate comparison experiments. We analyzed the sizing content and composition on the surface of two kinds of carbon fibers by IR and NMR; we also observed both the chemical and physical surface state of two kinds of carbon fibers before and after desizing by SEM and XPS. Using contact angle tester, we measured the wetting properties of both carbon fibers, before and after desizing, with TDE85resin, and obtained the surface energy through Owens two liquids method. The results showed that the main component of the sizing on two kinds of carbon fibers was a bisphenol A type epoxy resin, DGEBA, whose content was about1%. Domestic MT700C carbon fiber’s surface was coarse, but Toray T700SC carbon fiber’s surface was smooth. The O/C ration of MT700C’s surface is higher than that of T700SC’s surface, so TDE85had a good wetting property with T700C.We also measured the three different resin systems composites’(602,603and606systems) interlayer shear strength under both dry and wet environments by universal testing machine to study the properties of the interfacial. The results showed that, compared with T700SC/602and T700SC/603composites system, MT700C/602and MT700C/603composites system had a higher interlayer shear strength under dry state, however, under wet state, had a lower retention rate of shear strength. Thus, MT700C/602and MT700C/603composites system showed a weak interface and moisture performance.We measured the three systems’ mentioned above changes of tan δ under dry and wet state. The results showed that when reached certain moisture degree, MT700C/602and MT700C/603composites’ phase separated, two tan δ peaks mean two glass transition temperatures. However,603resin systems also had this phenomenon because it was composed of two different components.