The purpose of this work was to modify the surface of parawood sawdust (Hevea brasiliensis) microcrystalline cellulose (PW-MCC) used as reinforcing agent in polypropylene composites with benzoyl chloride under a mechanochemistry process.
The acetylated PW-MCC was produced from heterogeneous condition using planetary ball mill process at a rotation speed of 400 rpm. Before the esterification reaction, PW-MCC was pre-treated with pyridine at 60°C for 1 h in order to penetrate and swell the cellulose structure. The optimum condition of esterified PW-MCC with various molar ratios of benzoyl chloride/anhydroglucose unit (AGU) was studied. The degree of substitution, functional group, thermal stability and morphology of esterified cellulose were characterized by 1H-nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA) and scanning electron microscopy (SEM).
The functional group from FTIR confirmed that PW-MCC was successfully esterified with benzoyl chloride. The optimum condition which gave the maximum degree of substitution at 3.00 was achieved by using benzoyl chloride/AGU at 5 for 1 h. SEM analysis revealed that the modified PW-MCC surface became rougher than the unmodified PW-MCC surface. The polypropylene composites with 5-30 wt% PW-MCC and esterified PW-MCC were prepared without compatibilizer.
The composites with esterified PW-MCC enhanced water resistance and thermal stability when compared to composites with PW-MCC.
