Abstract:
This work focuses on the enhancement of crystallization behavior of polylactide (PLA). The small crystalline of polymer was used to induce nuclei for crystallization. The small crystalline of chitin whisker (CW) was prepared by acid hydrolysis. In order to enhance the compatibility between CW and PLA matrix, CW was grafted with acid terminated poly(D,L-lactic acid) (PDLLA) by coupling reaction to obtain PLA-g-CW. Then, the CW and PLA-g-CW were used as nucleating agents by compounding with PLA pellets at various contents from 0.1-0.3 phr by cast film extrusion. The SEM images of nanocomposites showed more agglomeration of whiskers with the increasing of CW or PLA-g-CW contents. Nevertheless, PLA/PLA-g-CW exhibited smaller size of agglomerated particles and better dispersion comparing to PLA/CW at same compositions due to the compatibility between CW and PLA was increased by grafting with PDLLA. The SEM images related to the DSC and POM results which indicated that the PLA-g-CW nanocomposite showed more effective nucleating agent of PLA than CW because of their well-dispersion. The introduction of PLA-g-CW at 0.1 phr significantly decreased the Tcc and increase Tc of nanocomposite. Moreover, PLA/PLA-g-CW0.1 also exhibited the highest degree of crystallinity comparing with the others. Therefore, PLA-g-CW at 0.1 phr was the most effective nucleating agent which enhanced the crystallization rate and degree of crystallinity of PLA.
