接枝改性纤维素纳米晶增强聚乳酸

Reinforcing Polylactide with Grafting Modified Cellulose Nanocrystals

在碱性溶液中,聚乙二醇二缩水甘油醚(PEG)接枝到纤维素纳米晶(CNC)表面,得到聚乙二醇接枝纤维素纳米晶(CNC-g-PEG)。其化学结构通过傅里叶变换红外光谱确认。通过哈克密炼机熔融共混制备了聚乳酸(PLA)/CNC-g-PEG共混物,研究了CNC-g-PEG含量对共混物的热性能和力学性能的影响。结果表明,CNC-g-PEG的引入对PLA的玻璃化转变温度几乎没有影响,但使PLA的结晶温度降低,熔融温度和结晶度提高。另外,PLA/CNCg-PEG共混物的热稳定性有所降低。PLA/CNC-g-PEG共混物的断裂伸长率随CNC-g-PEG的含量增加而逐渐降低,但拉伸模量和强度随之提高,显示了CNC-g-PEG对PLA具有增强作用。

CNC-g-PEG was prepared by grafting of polyethylene glycol diglycidyl ether （PEG） onto cellulose nanoerystals （CNC） under alkaline solution. The chemical structure was confirmed by Fourier transform infrared （FTIR） spectroscopy. PLA/CNC-g-PEG blends were prepared by a Haake internal melt mixer. The thermal and mechanical properties of the blends were investigated as a function of CNC-g-PEG content. The results show that the glass transition temperature of PLA is barely influenced by the addition of CNC-g-PEG, but the crystallization temperature of PLA decreases and the melting temperature and erystallinity increase. Besides, the thermal stability of blends decreases. The elongation at break of PLA/ CNC-g-PEG blends decreases with the content of CNC-g-PEG, but the tensile modulus and strength increase, which indicates that CNC-g-PEG has a reinforcing effect on PLA.