Sustainable potato peel powder–LLDPE biocomposite preparation and effect of maleic anhydride-grafted polyolefins on their properties

Potato peel (POPL), an agricultural waste material, obtained from food industry has been used as filler in the powdered form in linear low-density polyethylene (LLDPE) matrix up to 40% (w/w) to prepare biocomposites. The effect of addition of functional polyolefin compatibilizers—maleic anhydride-grafted polypropylene (MA-g-PP) and maleic anhydride-grafted polyethylene (MA-g-LLDPE), up to 5% (w/w) in POPL/LLDPE biocomposites were also studied. Scanning electron microscope was used for morphological characterization and X-ray diffraction for crystallization studies. Tensile strength of LLDPE biocomposites with MA-g-LLDPE compatibilizer reduced only in the range of 12.0–13.4 MPa compared to 14.6 MPa in neat LLDPE, however, reduced up to 40% in LLDPE biocomposites with 40% POPL content. Remarkable improvement in tensile modulus from 75.7 to maximum 703 MPa was achieved among the biocomposites. Mechanical properties of LLDPE biocomposites with 10% (w/w) POPL filler were comparable to neat LLDPE. Addition of maleic anhydride-grafted polyolefins has enhanced flexural strength and flexural modulus of biocomposites with compatibilizers’ up to 128 and 188%, respectively, compared to neat LLDPE. Low values of water absorption were observed for the biocomposites. The study showed that potato peel powder as inexpensive and potentially sustainable filler in the preparation of LLDPE biocomposites which could be biodegradable and environmentally friendly.