Polylactic acid/carbon fiber composites: Effects of polylactic acid-g-maleic anhydride on mechanical properties, thermal behavior, surface compatibility, and electrical characteristics

This study uses a reactive extrusion for the grafting of maleic anhydride on polylactic acid in order to form polylactic acid grafted maleic anhydride that serves as a compatibilizer between polylactic acid and carbon fiber. The effects of different ratios of the free radical initiator to maleic anhydride as well as the amounts of polylactic acid grafted maleic anhydride on the mechanical properties, interfacial compatibility, thermal behaviors, and electrical properties of the polylactic acid/carbon fiber composites are discussed. The test results indicate that using polylactic acid grafted maleic anhydride as compatibilizer improves the interfacial compatibility of polylactic acid/carbon fiber composites, which in turn contributes to a high electrical conductivity and the electromagnetic interference shielding effectiveness, while decreasing the surface resistance and increases. In addition, the amount of polylactic acid grafted maleic anhydride has a positive influence on their tensile properties, flexural strength, and impact strength. The differential scanning calorimetry results indicate that a high polylactic acid grafted maleic anhydride content is also conducive to crystallinity, but is not in related to the melting temperature. According to the scanning electronic microscope observation, the fractured composites that are inflicted by an impact have considerably few traces of the fibers being pulled out, which is ascribed to polylactic acid that can completely enwrap carbon fiber. Therefore, the incorporation of polylactic acid grafted maleic anhydride is proven to strengthen polylactic acid/carbon fiber composites, exemplified by their improved interfacial compatibility and properties.