Physical properties of polypropylene composites with hydrophobized cellulose powder by soybean oil

Abstract

ABSTRACTCellulose materials have attracted lots of interest as potential natural fillers in the production of green polymer composites because they are ecofriendly and economic. In this study, to improve the interfacial bonding strength between cellulose powder and a hydrophobic polypropylene (PP) matrix, the surface hydrophobization of cellulose powder by soybean oil was carried out via a simple transesterification reaction procedure. Weight change measurements, Fourier transform infrared spectroscopy, and compatibility testing were used to quantitatively and qualitatively analyze the hydrophobization of the cellulose powder. By changing the hydrophobization conditions, the soybean oil content attached to the cellulose powder changed from 8.0 to 57.8%. PP composites with 20% of each hydrophobized cellulose powder were prepared by melt blending followed by compression molding. The mechanical properties of the PP composites were investigated with a universal testing machine and an Izod impact tester. Compared to the composite with pristine cellulose powder, the PP composite with the hydrophobized cellulose powder and an attached soybean oil content of 29.6% showed largely increased impact strength (46.3%), tensile strength (47.5%), and elongation at break (27.3%) values. The scanning electron microscopy images for the fracture surfaces of the composites showed that the hydrophobization induced much stronger interfacial bonding between the PP matrix and cellulose powder. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42929.