Pengaruh Variasi Kitosan Terhadap Karakteristik Mekanik Bioplastik Berbasis Pati Dari Biji Karet (Hevea Brasiliensis)

Abstract

This study aims to analyze the effect of chitosan variation on the mechanical and physical properties of starch-based bioplastics derived from rubber seeds (Hevea brasiliensis). Bioplastics were prepared using the solvent casting method with a fixed composition of rubber seed starch (4 g) and glycerol (0.6 ml), while chitosan was varied at 0, 4, 8, 12, and 16 g. The tested parameters included tensile strength, water absorption, functional group analysis using FTIR, and surface morphology using SEM. The results showed that chitosan addition significantly improved tensile strength, with the optimum value of 6 MPa achieved at 8 g of chitosan. Water absorption decreased with increasing chitosan concentration, reaching the lowest value of 87% at 16 g of chitosan. FTIR analysis confirmed the formation of hydrogen bonds between hydroxyl groups of starch and amino groups of chitosan, while SEM images revealed a more homogeneous and compact surface structure with chitosan incorporation. Although tensile strength met the SNI 7188-7:2017 standard (1–10 MPa), water absorption remained far above the SNI ISO 62:2011 requirement (10–50%). Therefore, rubber seed starch combined with chitosan shows potential as an environmentally friendly bioplastic material, but further formulation optimization is required to improve water resistance.