Preparation of Chitin Whisker and Effect to Crystallization of Polylactide

Abstract

The aim of this study was to investigate the effect of chitin whisker (CW) to the crystallization of polylactide (PLA) nanocomposite films. CW which obtained from acidolysis reaction was compounded with PLA pellets into nanocomposite films by cast film extrusion. The morphology and crystallinity of CW were observed by TEM and XRD, illustrated that the dimension of whisker was affected by hydrolysis time. Increasing of hydrolysis time, the length of whisker was more regular with narrower distribution. Moreover, the crystallinity of whisker was obviously increased after acid hydrolysis. The nanocomposite film showed rough surface compared to pure PLA film due to some agglomeration of nanoparticles. However, CW and PLA were well-mixed with no phase separation. The introduction of 0.1 phr of CW decrease cold-crystallization temperature (Tcc) from about 121 °C to 118 °C and also increase the degree of crystallinity around 10%. There was no difference of thermal transition temperature between pure PLA and nanocomposite films with the addition of CW more than 0.1 phr which inspected by DSC. Despite the transition temperature express insignificantly different, the degree of crystallinity of nanocomposite was increase, indicating that chitin whisker would induce the crystallinity of PLA.