This study addresses the effect of the coatings prepared from aramid nanofibers (ANFs) on the surface treatment of aramid fiber and reinforced polycarbonate (PC) composite (AF/PC). Aramid fiber's smooth, inert surface bonds poorly with polycarbonate. In this research, the PC‐ANF coating was made by the PC/CH2Cl2 solution, which was modified by aramid nanofibers to improve the interfacial adhesion and compatibility of aramid fiber/PC composites. What's more, the silane (KH570) was added to improve the dispersion and interfacial strength of ANF and PC. The results showed the water contact angle of the aramid fiber modified by PSi‐ANF coating was reduced, indicating the modified fiber has a better wettability. The interfacial bonding strength between PC and aramid fiber increased by 77.2%. The AF/PC composites were prepared by hot‐compression, which the aramid fiber wovens treated with P‐ANF coating, PSi‐ANF coating. The tensile strength, flexural strength, interlaminar shear strength, and impact strength of the AF/PC composite reinforced by AF treated with PSi‐ANF containing 2.0 wt% ANF increased by 62.0%, 81.9%, 49.5%, and 27.6%, respectively. Therefore, this study demonstrates that incorporating ANF interphase may offer an innovative and practical way for enhancing the interface bonding properties of aramid‐reinforced composites.

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Thermal properties of polyimides with main chain containing alicyclic units derived from 3,3 0 4,4 0 -oxydiphthalic anhydride (ODPA) and several alicycliccontaining diamine monomers, including 1,4-bis (4aminophenoxymethylene) cyclohexane (BAMC), 1,4-bis (3-aminophenoxymethylene) cyclohexane (mBAMC), 1,4-bis (4-aminobenzoyoloxymethyl) cyclohexane (BAZMC), and 1,4-bis (3-aminobenzoyoloxymethyl) cyclohexane (mBAZMC) were characterized in detail. The thermal stability, apparent activation energy, and evolved gas analysis of these polyimides were done using thermogravimetric analysis (TGA) coupled with Fourier transform infrared (FTIR) spectroscopy. Experimental results indicated that the resulting polyimides showed fairly high thermal stability, no weight loss was detected before a temperature of 4008C in nitrogen, and the values of glass-transition temperature of them were in the range of 134-1818C. Activation energy for the initial thermal degradation of polyimide derived from ODPA and mBAMC in nitrogen were 166 and 162 kJ/mol in two different methods. The TG-IR results represented that the major evolved products from the nonoxidative thermal degradation were detected to be hydrocarbons, CO, CO 2 , H 2 O, and aromatic compounds.

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