退火对有机化竹纤维/聚乳酸复合材料性能的影响

Effect of Annealing on the Properties of Organized Bamboo Fiber/Polylactic Acid Composite

以有机化竹纤维(OBF)为成核剂,通过双螺杆挤出机制备了可完全生物降解的PLA/OBF复合材料。采用差示扫描量热仪(DSC)、X射线衍射仪(XRD)、偏光显微镜(POM)和热变形、维卡软化点温度测定仪分析了在不同退火条件下,成核剂OBF对PLA结晶及耐热性能的影响。结果表明:OBF是一种有效成核剂,当OBF含量为1.2%时,PLA的结晶速率加快,成核密度增加、晶体尺寸减小,并且结晶度变大,纯PLA的结晶度为17.3%,添加了OBF的PLA结晶度提高到27.9%;退火处理可以有效改善PLA的结晶及耐热性能,但对PLA的晶型没有影响,在90℃退火10 min时,纯PLA的结晶度提高到58.7%,维卡软化点达到57.1℃;PLA/OBF的结晶度提高到60.1%,维卡软化点达到85.0℃。

The completely biodegradable PLA/OBF composite were prepared through a twin-screw extruder by using the organized bamboo fiber （OBF） as the nucleating agent. The influence of OBF on the crystallization and thermal behavior of PLA was studied at different annealing conditions by differential scanning calorimetry （ DSC ）, X-ray diffraction （ XRD ） , polarized optical microscope （POM）,and vicar softening point tester. It was showed that OBF was an effective nucleating agent of PLA. When OBF was 1.2% ,the crystallization rate of PLA increased,the nucleation density increased,the crystal size decreased and the crystallinity increased. The crystallinity of pure PLA was 17.3% ,and the crystallinity of PLA with OBF increased to 27.9%. Annealing treatment could improve the crystallization and heat resistance of PLA,but it had no effect on the crystal form of PLA. The crystallinity of neat PLA was increased to 58.7% and the Vicar softening point was 57.1℃ ,the crystallinity of PLA/OBF was increased to 60.1% and the Vicat softening point was 85.0℃ ,while PLA/OBF was annealed at 90℃ for 10 minutes.