Extraction of Cellulose from Arenga Pinnata “Ijuk” Fiber for Polypropylene Composite: Effect of Multistage Chemical Treatment on the Crystallinity and Thermal Behaviour of Composite

Cellulose-based impact polypropylene copolymers (IPC) has been developed by utilizing Arenga pinnata “ijuk” fiber. The cellulose from pristine ijuk fiber (IF) was extracted via alkalization and bleaching treatment using NaClO, with KMnO₄ as the activator. The purpose of using KMNO₄ is to replace the use of acid buffers in every process that uses NaClO. The fibers’ properties, namely their compound content, morphology, crystallinity index, and crystallite size, were characterized and investigated to examine the treatment effect. The Fourier-transform infrared (FTIR) spectroscopy shows that the majority of lignin and hemicellulose were removed throughout the treatment process. FTIR semi-quantitative analysis, based on absorbance ratio, reveals that IFB5, the fiber treated with 5% NaClO for 5 h, exhibits the highest cellulose content. The scanning electron microscopy (SEM) was performed to observe the fibers’ morphology. The X-ray diffraction (XRD) characterization reveals that IFB5 contains cellulose I_β type and exhibits the highest crystallinity index, 62.27%. The fiber was then utilized to develop a cellulose-based IPC composite. The IPC Ijuk Treatment (IPC Ijuk T) shows a good bonding characteristic between fiber and the matrix, the highest crystallinity percentage, 67,18%, the lowest melting point, 162.8 °C, and the highest thermal stability, started to degrade at 265 °C and decomposed at 447 °C. Thus, IPC Ijuk T can be considered applicable as IPC composite filler.