Effect of mercerized melon (Citrullus lanatus) husk on the mechanical properties of polypropylene composite

Abstract

Effect of mercerized melon husks on the mechanical properties of polypropylene was studied. Melon husk was mercerized using NaOH, dried and reduced to ultra-fine particles using sieve size of 75µm and used for compounding polypropylene. The result of the filler characteristics showed that mercerized melon husks (MMH) had better and improved properties compared to the unmercerized (UMH) in terms of pH (UMH; 5.16 and MMH; 8.25), lignin contents (UMH; 11.50% and MMH; 5.69%), moisture content (UMH; 3.30% and MMH; 1.95%) and bulk density (UMH; 0.87g/ml and MMH; 0.64g/ml) respectively. The mechanical properties investigated showed increased tensile strength for both fillers at 40g loadings in terms of tensile strength (UMH; 31.85-45.88MPa) and (MMH; 31.85-52.16MPa) before decreasing, tensile modulus (UMH; 1005.17-1042.23MPa) and (MMH; 1005.17-1069.94MPa), hardness (UMH; 67.50-115.67Shore A) and (MMH; 67.50-133.42Shore A),while there was quite noticeable decrease in properties such as elongation at break (UMH; 290.11-180.35%) and (MMH; 290.11-172.55%), impact strength (UMH; 136.55-93.29J/mm2) and (MMH; 136.55-102.17J/mm2) and abrasion resistance (UMH; 95.65-54.25%) and (MMH; 95.65-63.26%) as filler loadings increases. However, mercerized melon husk filled composites showed excellent and enhanced performance when compared with unmercerized and unfilled polypropylene matrices revealing the effectiveness of chemical modification on natural fibres.