Silylation and characterization of microcrystalline cellulose isolated from indonesian native oil palm empty fruit bunch

Abstract

Silylation of microcrystalline cellulose (MCC), isolated from Indonesian native oil palm empty fruit bunch (OPEFB), using aminosilane compound synthesized through aminolysis of 3-glycidoxypropyltrimethoxysilane (GPTMS) with ethylenediamine (EDA) has been conducted in this study. Generally, there are three steps performed to isolate MCC before silylation process, i.e. bleaching, alkaline treatment and acid hydrolysis. All products resulted from bleaching, alkaline and acid hydrolysis treatments were characterized using Fourier Transform Infrared (FTIR) spectroscopy. Two conditions were optimized in this study which they were an acid concentration in hydrolysis process and aminosilane ratio in silylation process. The preliminary study regarding optimizing acid hydrolysis process by varying sulfuric acid concentration was obtained an optimum sulfuric acid concentration by 45% having highest crystallinity index (CI) measured using x-ray diffraction (XRD) data. The morphological structure of MCC was rod-like crystalline structure confirmed by transmission electron microscopy (TEM). The silylating agent was varied in this study with the ratio to MCC by 1:1, 3:1 and 5:1 mmol g−1. Based on loading analysis, the aminosilane with ratio 1:1 mmol g−1 was noted as optimum concentration having high loading yield by 79.2%. Effect of silylation on MCC properties was, on the one hand, it decreased the CI and crystallite size, however, on the other hand, it increased the surface area and pore volume.