文献类型：期刊文献

中文题名：等温结晶对杨木纤维/聚乳酸复合材料性能的影响

英文题名：Effects of Isothermal Crystallization on the Properties of Wood Fiber/PLA Composites

作者：孙晓婷[1] 常亮[1] 唐启恒[1] 任一萍[1] 郭文静[1]

第一作者：孙晓婷

通信作者：Guo, Wenjing

机构：[1]中国林业科学研究院木材工业研究所

年份：2018

卷号：54

期号：3

起止页码：97-107

中文期刊名：林业科学

外文期刊名：Scientia Silvae Sinicae

收录：CSTPCD;;EI(收录号：20183805826865);Scopus;北大核心:【北大核心2017】；CSCD:【CSCD2017_2018】；

基金：中央级公益性科研院所基本科研业务费专项资金(CAFYBB2016ZD006)

语种：中文

中文关键词：等温结晶;聚乳酸;WF/PLA复合材料;结晶性能;力学性能

外文关键词：isothermal crystallization;poly(lactic acid);WF/PLA composites;crystallization properties;mechanical properties

分类号：TS6

摘要：【目的】研究等温结晶处理对木纤维/聚乳酸复合材料结晶、物理和力学性能的影响,为提高聚乳酸复合材料的加工和使用性能提供依据。【方法】采用热压成型方式制备纯聚乳酸板材和杨木纤维(WF)/聚乳酸(PLA)复合材料,在冷却过程中将材料置于不同温度(90、100、110、120和130℃)下进行等温结晶处理,通过示差扫描量热仪(DSC)分析PLA及其复合材料的结晶度和熔融特性,利用偏光显微镜(POM)观察等温结晶处理条件下PLA的结晶过程,结合结晶形态分析等温结晶处理对PLA结晶性能的影响。基于扫描电镜(SEM)和凝胶色谱仪(GPC)等测试手段表征材料的微观结构和分子质量,分析其对材料物理力学性能的影响。【结果】等温结晶处理后,纯PLA板和WF/PLA复合材料的结晶度分别由4.6%和15.1%提高至24.8%和40.5%;经90、100和110℃等温结晶处理后,WF/PLA复合材料的冲击断面与未处理WF/PLA复合材料相比,明显有长纤维从PLA基体中拔出,等温结晶处理弱化了WF与PLA界面结合;等温结晶处理后,PLA分子质量有所下降;POM测试显示,晶体尺寸随着结晶温度升高而增大;与未处理材对比,等温结晶处理后纯PLA板的弯曲性能和拉伸强度均得到提高,WF/PLA复合材料的弯曲弹性模量增加,但弯曲强度和拉伸强度在多数处理条件下都有所降低。【结论】等温结晶处理后,纯PLA板和WF/PLA复合材料的结晶度均提高,且木纤维促进晶核生成,WF/PLA复合材料的结晶度增加更多;等温结晶温度低,晶体尺寸变小,等温结晶温度高,晶体尺寸变大;等温结晶处理后,纯PLA板的抗弯强度和拉伸强度得到提高,WF/PLA复合材料的力学性能变化规律不明显。等温结晶处理对纯PLA板和WF/PLA复合材料力学性能影响不同,可能与等温结晶处理后弱化WF与PLA界面结合有关。
【Objective】The effects of isothermal crystallization on the crystallinity,physical and mechanical properties of wood fiber(WF)/poly(lactic acid)(PLA)composites were investigated in this study,which provides the basis for improving the processing and application of PLA composites.【Method】The pure PLA panels and WF/PLA composites were prepared by hot-pressing and followed by a cooling process for isothermal crystallization at different temperatures(90,100,110,120 and 130℃).The crystallinity and melting characteristics of pure PLA panels and WF/PLA composites were characterized by differential scanning calorimeter(DSC),and the isothermal crystallization process was observed by polarizing microscope(POM),then the effects of isothermal crystallization process on the crystallization properties of PLA were analyzed by combining with crystalline morphology.Moreover,the effects of microstructures and molecular weights on the mechanical properties were also investigated by scanning electron microscope(SEM)and gel chromatography(GPC).【Result】The results showed that the crystallinity of pure PLA panels and composites increased from 4.6%and 15.1%to 24.8%and 40.5%,respectively.Compared with the fracture surfaces of virgin WF/PLA composite,it was obvious to seen that wood fibers were pulled out from the matrix of WF/PLA after isothermal crystallization at 90,100 and 110℃,indicating that the isothermal crystallization make a poor effect on interfacial bonding.The molecular weight of PLA decreased after the isothermal crystallization.According to the result of POM,it could be seen that the crystal size increased with increasing isothermal crystallization temperatures.After isothermal crystallization,the bending properties and tensile strength of pure PLA panels were improved.Moreover,the flexural modulus of WF/PLA also increased with isothermal temperatures,however,the flexural and tensile strength reduced to some extent.【Conclusion】The crystallinities of pure PLA panels and WF/PLA composites increased gradually after the isothermal crystallization,moreover,the crystallinity of the WF/composites showed a larger improvement due to the ability of promoting nucleation of wood fiber.The lower of the isothermal crystallization temperature,the smaller of the crystal size was.The higher of the isothermal crystallization temperature,the larger of the crystal size was.The bending and tensile strength of pure PLA panels were improved after isothermal crystallization.However,the mechanical properties of WF/PLA showed irregular rules.Isothermal crystallization exhibited different influences on the mechanical properties of pure PLA panels and its composites,which maybe relate to the poor interfacial bonding.