Effects of different types of maleic anhydride-modified polypropylene on the interfacial shear strengths of carbon fiber-reinforced polypropylene composites

Herein, the effects of three maleic anhydride-modified polypropylene (MAPP) specimens with different MA contents and crystallinities on the interfacial shear strengths (IFSSs) of PP and carbon fiber (CF) were investigated and compared by using microdroplet tests. The IFSS values showed little dependence on the MA content of the MAPP. Localization of the MAPP at the interphase was shown experimentally, which indicated sufficient chemical interactions involving covalent bonds and hydrogen bonds at the interface regardless of the MA content. When the chemical interactions at the interface are sufficient, the IFSS values are attributed to the crystallinity at the interphase. The crystallinity at the interphase depends on the crystallinity of the MAPP added, and higher crystallinity resulted in a higher IFSS.