接枝改性纤维素纳米晶对聚乳酸结晶性能的影响

Influence of Graft Cellulose Nanocrystals on the Crystallization Properties of Polylactide

通过熔融共混将接枝改性的纤维素纳米晶(CNC-g-PEG)引入聚乳酸(PLA),制备了PLA/CNC-g-PEG纳米复合物。采用差示扫描量热分析仪研究了PLA、PLA/CNC和PLA/CNC-g-PLA分别在不同升温速率下的非等温结晶形为。研究表明,CNC能促进PLA的结晶成核,使其结晶温度显著降低,而CNC接枝PEG后,与PLA的相容性增加,促进PLA的成核作用更强,使得PLA的结晶温度进一步降低。通过Kissinger方程计算了各样品的结晶活化能,发现CNC显著降低了PLA的结晶活化能,而接枝改性后的CNC与PLA的相容性增加,分子链间相互作用变强,阻碍了PLA分子链的运动,使得样品的活化能略微提高。

Graft cellulose nanocrystals （CNC-g-PEG） was incorporated into polylactide （PLA） by meh blending to obtain PLA/CNC-g-PEG nanocomposite. The non-isothermal crystallization behaviors of PLA, PLA/CNC and PLA/CNC-g-PEG blend under different heating rates were studied by differential scanning calorimeter. The results show that CNC promotes the crystallization nucleation of PLA, leading to in a significant reduction in crystallization temperature. After CNC is grafted to PEG, its compatibility with PLA increases, and the nucleation of PLA is enhanced, which further decreases the crystallization temperature of PEA. The crystallization activation energies of the samples were calculated from Kissinger＇s model. It is found that CNC significantly reduces the activation energy of PLA. The compatibility of PLA with the graft CNC is enhanced, and the molecular chains interactions become stronger, which can retard the movement of PLA molecular chains, and result in the slightly increase of the activation energy of the sample.