A potential bio-filler: The substitution effect of furfural modified clam shell for carbonate calcium in polypropylene

Shell waste has the potential to be used as a bio-filler. In this work, the commercial calcium carbonate and furfural modified clam shell were used as fillers in polypropylene. Both fillers were characterized and analyzed by X-ray diffraction, scanning electron microscopy equipped with an energy dispersive spectrometer, particle size analyzer, Fourier transformed infrared spectroscopy, and contact angle measurement. The mechanical and thermal properties of unfilled polypropylene and polypropylene composites were investigated as well. X-ray diffraction and energy dispersive spectrometer analysis indicated that the major phase of calcium carbonate was calcite; of modified clam shell, calcite and aragonite. The calcium carbonate displayed a cubic-like morphology with a smaller particle size as compared with that of modified clam shell. The contact angle measurements indicated that calcium carbonate was fully hydrophobic, while modified clam shell was amphiphilic. Thermal gravimetric analyses confirmed the reinforcement effects of both calcium carbonate and modified clam shell in polypropylene composites. Mechanical property studies showed that the inclusion of modified clam shell played the role mainly of toughening the polypropylene; of calcium carbonate, that of reinforcing, with a nonsignificant toughening effect. The optimal filler ratio of modified clam shell could reach 15 wt.%, as compared with 10 wt.% for calcium carbonate, making it possible for substituting calcium carbonate in polypropylene.