Effect of epoxidized soybean oil grafted poly(12-hydroxy stearate) on mechanical and thermal properties of microcrystalline cellulose fibers/polypropylene composites

A new green compatibilizer named epoxidized soybean oil grafted poly(12-hydroxy stearate) (ESO-g-PHS) was successfully synthesized using 12-hydroxy stearic acid and epoxidized soybean oil (ESO). The chemical structure of ESO-g-PHS was investigated through Fourier transformed infrared spectroscopy, thermogravimetric analysis, and gel permeation chromatography. ESO-g-PHS was used as a compatibilizer to enhance the interfacial compatibility between polypropylene (PP) and microcrystalline cellulose fibers (MCF). The results showed that the impact strength and tensile strength were 33.55 and 27.57 MPa when the content loading of MCF reached 10 wt% and ESO-g-PHS was 4 wt%, which enhanced by 75.4 and 30.04 %, respectively, compared to that of composites without ESO-g-PHS. In addition, the SEM images of the fracture surfaces display that PP was highly bonded to MCF with ESO-g-PHS treated. In addition, the wide angle X-ray diffraction measurement revealed that the addition of ESO-g-PHS did not change the crystal structure of PP. Moreover, there was a slight improvement in thermal properties for PP composites with the addition of ESO-g-PHS.