Study of Alkalization to the Crystallinity and the Thermal Behavior of Arenga Pinnata “Ijuk” Fibers-Based Polylactic Acid (PLA) Biocomposite

Abstract

The pollution due to non-degradable material such as plastics, has led to studies about the development of environmental-friendly materials. Because of natural sources-based materials and their biodegradability, polylactid acid (PLA) and ijuk fiber are interesting to be modified into a composite. Furthermore this study is also expected to reduce the impact of environmental problems. Surface modification of ijuk fiber through alkalinization, was aimed to enhance compatibility between the ijuk fiber and the PLA, in order to improve properties of the composite such as crytallinity and thermal behavior. To investigate in detail about this modification, this research also studied effect of the alkalinized ijuk fiber and the PLA composition to the crystallinity and the thermal behavior of the composites. The experimental results were investigated by FTIR to qualitatively analyze compounds content in the ijuk fiber before and after alkalinization, DSC and TGA to study crystallinity and thermal stability behavior of the composite, respectively and FE-SEM to observe morphological behavior like compatibility between the ijuk fiber and the PLA. The FE-SEM observation showed that alkalinization of the ijuk fiber led to wettability enhancement between the ijuk fiber and the PLA. This may be caused by annihilating lignin and hemicellulose. Furthermore this treatment leads to expose micro-fibril cellulose (MFC) in the ijuk fiber and then to enhancement of bonding affinity with the PLA. This phenomenon gives a possibility for the PLA in the composite to increase its crystallinity due to nucleating effect of crystalline parts in the MFC. DSC measurements show that addition of the alkalinized ijuk fiber tends to increase the crystallinity of PLA in the composites.Keywords: alkalization, Arenga Pinnata, compatibility, crystallinity, PLA, thermal stability