The effect of alkali treatment on the mechanical properties of date seed particulates waste polypropylene filled composites

Abstract

Date seeds collected as waste were reduced to 63 µm particles and treated with NaOH (aq) at 1, 3, 5, 7 and 10 %. The extent of chemical modification was assessed using FTIR analysis. The waste polypropylene (wPP)/date seed particles (DSP) composites filled with untreated and treated particles at 20 % filler loadings were fabricated using compounding and compression moulding techniques by means of two rolls mill. Tensile, flexural, impact tests and hardness (HV) were conducted and evaluated. Subsequently, a morphological study of the fractured surface of the composites was achieved using SEM. The application of alkali treatment enhanced various properties of the composites at the optimal concentration of 10 % w/v. Specifically, the tensile strength, flexural strength, elongation at break, impact strength, and hardness were improved, resulting in values of 28.86 MPa, 140 MPa, 172.5 %, 0.92 J/m², and 23.8 Hv, respectively. While tensile and flexural moduli showed a decrease with increasing alkali concentration. The SEM of the fractured surface of the treated composite revealed a better dispersion of filler particles within the matrix with no cluster seen compared to the untreated.