1st ICRIL-International Conference on Innovation in Science and Technology (lICIST 2015) IICIST 2015 Proceedings 59 20 th April 2015, Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia Effect of Acid Hydrolysis Time on Tensile and Morphological Properties of Microcrystalline Chitin Filled Polylactic Acid Biocomposites Reza Arjmandi 1 , Mohd Hakim Ramadhan Mustaffa Kamal 2 , Tariq Iqbal 2 , Azman Hassan 1 *, Zainoha Zakaria 3 , Syazeven Effatin Azma Mohd Asri 3 1 Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai UTM, Johor, Malaysia 2 Department of Bioprocess Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai UTM, Johor, Malaysia 3 Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, UTM 81310, Skudai, Johor, Malaysia * corresponding author: azmanh@cheme.utm.my Abstract The objective of this study is to investigate the effect of acid hydrolysis time on microcrystalline chitin (MCC) filled polylactic acid (PLA) biocomposites using solution casting method. MCC was produced from commercial chitin using controlled hydrolysis process at four different hydrolysis time; 15, 30, 45 and 60 min. The tensile and morphological properties of PLA/MCC biocomposites were investigated using tensile testing machine and atomic force microscopy (AFM), respectively. Tensile strength and Young’s modulus of PLA/MCC biocomposites increased gradually by increasing hydrolysis time. The biocomposites with longest hydrolysis time (60 min) showed the higher tensile strength, Young’s modulus and elongation at break values. AFM analysis showed homogeneous dispersion of MCC fillers with smaller particles size at longer hydrolysis time, resulted in smother surface morphology compared to biocomposites with shorter hydrolysis time. Keywords. Microcrystalline chitin; Polylactic acid; Biocomposites; Tensile properties; Atomic force microscopy 1 Introduction Nowadays, biodegradable polymers and biocomposites from renewable sources has become a major interest due to continuously decreasing of petroleum reserves and environmental concerns. In addition, these materials has caught great market share which grown tremendously in the plastic industry [1]. Polylactic acid (PLA) is a type of thermoplastic aliphatic polyester which can be derived from bio renewable sugar based sources such as corn starch. Due to its biodegradability properties, it is considered as a sustainable alternative to petroleum-based polymers for many application. Additionally, PLA biocomposites have essential applications on water and milk bottles, food packaging, barriers for sanitary products and diapers, pharmaceutical industries and automotive applications [2, 3]. However, it cannot be denied that PLA also has its own weakness such as low water vapor and gas barrier, its brittleness and low thermal stability properties. Due to these limitations, reinforcement with stabilizer filling such as chitin is considered as an alternative to overcome the shortcomings [2]. The abundant of natural sources motivates researchers to produce biocomposites, but it has restrictions due to its limited solubility and functionality. Chitin is a ubiquitous natural biopolymer that is mostly founded next to cellulose discovery. Chitin is a polysaccharide which found as α-crystalline form in many crustacean sources such as crabs, shrimp shells and lobsters. Chitin is usually obtained through chemical treatments which discard large amount of chemical wastes. In the last decade, a biotechnological approach using lactic acid fermentation to purify chitin from crustacean waste is gaining its popularity due to its environmentally clean approach and cheaper production cost. It is a linear polymer of N-acetyl-D-glucosamine linked by α (1, 4) glycosidic bond that can be obtained from