Towards mechanically robust cellulose fiber-reinforced polypropylene composites with strong interfacial interaction through dual modification

Strong interfacial interaction between bamboo cellulose fiber (BCF) and a polymeric matrix is very important to improve the mechanical properties of cellulose fiber-reinforced polymeric composites. In this study, we developed an effective approach to enhance the interfacial adhesion through modifying both polypropylene (PP) and cellulose fiber. Maleic anhydride was mechanochemically grafted onto PP to achieve the interaction with the reactive hydroxyl groups on the surface of 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO)-oxidized bamboo cellulose fiber (TBCF). Fourier transform infrared spectra and X-ray diffraction analysis indicated the existence of strong interfacial interaction between TBCF and the modified PP matrix. It was further found by thermogravimetric analysis that about 5 wt% of PP formed a strong combining force with TBCF after melt compounding. The combination of mechanochemical modification of PP and TEMPO-mediated oxidation of BCF showed a synergistic effect on the tensile strength of the prepared composites. The tensile strength of modified PP/TBCF (50/50 wt%) composites prepared through dual modification was remarkably improved compared to those of neat PP/TBCF composites and modified PP/BCF composites, enhanced by about 112.4% and 53.8%, respectively.