成型加工条件对聚(D,L-乳酸)及其复合材料力学性能的影响

背景加工条件和加工温度会使聚乳酸[Poly(lacticacid),PLA]降解,损害力学性能. 目的探讨成型加工条件对聚(D,L-乳酸)(PDLLA),二苯基甲烷二异氰酸酯(MDI)扩链PDLLA和MDI扩链PDLLA/羟基磷灰石(HA)复合材料力学性能的影响.设计分组对照研究.地点和方法在华南理工大学材料学院完成实验.利用MDI作为扩链剂对PDLLA和PDLLA/HA复合材料扩链,合成MDI扩链PDLLA和MDI扩链PDLLA/HA复合材料,采用自行设计的模压挤出设备对其进行加工.主要观察指标成型加工条件对PDLLA,MDI扩链PDLLA和MDI扩链PDLLA/HA复合材料力学性能的影响.结果在模压温度165℃,挤出温度100℃、口模长度10mm的最佳成型工艺条件下,PDLLA和PDLLA/HA复合材料的弯曲强度分别为35.1MPa和31.2MPa,弯曲模量分别为2 413.6 MPa和1 735.0 MPa;在模压温度100℃,挤出温度100℃、口模长度10mm的最佳成型工艺条件下,PDLLA/MDI和PDLLA/HA/MDI复合材料的弯曲强度分别为51.3MPa和55.4 MPa,弯曲模量分别为1 830.9 MPa和2 068.5 MPa.结论成型加工条件对PDLLA,MDI扩链PDLLA和MDI扩链PDLLA/HA复合材料的力学性能影响显著,而且MDI扩链可显著提高PDLLA和PDLLA/HA复合材料的力学性能.

Effect of processing conditions on mechanical properties of poly(D,L-lactide) and MDI chain-extending poly(D,L-lactide)/hydroxyapatite composite

BACKGROUND: Polylactic acid (PLA) is very degradable in the processing conditions and at the processing temperature so its mechanical properties reduce greatly.OBJECTIVE: To investigate the effects of processing conditions on the mechanical properties of poly(D, L-lactide) (PDLLA), methylenediphenyl diisocyanate(MDI) chain-extending PDLLA(PDLLA/MDI) and MDI chain-extending PDLLA/hydroxyapatite (HA) composites (PDLLA/HA /MDI).DESIGN: A grouping and control study was designed.SETTING and METHODS: The experiment was carried out in the College of Materials, South China University of Technology. Using methylenediphenyl diisocyanate(MDI) as chain-extender to prepare MDI chain extending PDLLA(PDLLA/MDI) and MDI chain-extending PDLLA/HA composites (PDLLA/HA/MDI composites) and utilizing self-designed moulding and extruding equipment to process these biodegradable materials.MAIN OUTCOME MEASURE: Effects of processing condictions on PDLLA, PDLLA/MDI and PDLLA/HA/MDI.RESULTS: At the optimal processing conditions of molding temperature 165 ℃, extruding temperature 100 ℃ and mould chamber length 10 mm,bending strength of PDLLA and PDLLA/HA composites is 35.1 MPa and 31.2 MPa, respectively and their bending modulus is 2 413.6 MPa and 1 735.0 MPa, respectively. At the optimal processing conditions of molding temperature 100 ℃, extruding temperature 100 ℃ and mould chamber length 10 mm, bending strength of PDLLA/MD and PDLLA/HA/MDI composites is 51.3 MPa and 55.4 MPa, respectively and their bending modulus is 1 830. 9 MPa and 2068.5 MPa, respectively.CONCLUSION: The processing conditions affected obviously mechanical properties of PDLLA, PDLLA/MDI and PDLLA/HA/MDI composites and MDI chain-extending enhanced significantly mechanical properties of these materials.