Authors : Sarit Thanomchat and Kawee Srikulkit
Abstract: This research was aimed at improving properties of PLA by the addition of Cllulose Fibril (CF) prepared by the dissolution of cotton microcrystalline cellulose in NaOH/urea aqueous system, followed by regeneration of cellulose in an HCl bath. Then, surface hydrophobicity modification of CF was achieved by silanization reaction using hexadecyltrimethoxysilane to obtain Silane-g-CF. Following that, Silane-g-CF/PLA composites with various filler loadings of 0.5, 1.0, 3.0 and 5.0 wt% were prepared by twin screw extrusion and injection molding. The DSC results indicated that Silane-g-CF tended to perform nucleating ability for PLA by lowering the cold crystallization temperature (Tcc) as well as inducing the crystallization (Tc) at higher temperature. As consequence, the degree of PLA crystallinity increased in the presence of Silane-g-CF. It was found that Silane-g-CF enhanced the impact resistance of PLA up to 30% arising from the interfacial adhesion as well as compatibility between two phases. In addition, the plasticization effect of silane long alkyl chain resulted in an increase in the percent elongation at break. Unfortunately, the tensile strength and Young’s modulus slightly decreased. Finally, SEM micrographs of Silane-g-CF/PLA composites revealed the rougher fracture surface when compared to neat PLA, confirming the better interfacial adhesion and compatibility.
Sarit Thanomchat and Kawee Srikulkit, 2016. Thermal and Mechanical Properties of Polylactic Acid Filled with Organosilane Modified Cellulose Fibril. Journal of Engineering and Applied Sciences, 11: 2697-2702.