摘要
目的:采用自行设计的模压挤出设备系统探讨成型加工条件和MDI用量对聚(D,L)-乳酸/羟基磷灰石(PDLLA/HA)复合材料力学性能和形态结构的影响。方法:在辛酸亚锡的催化作用下由丙交酯开环聚合制备聚乳酸,并用二苯基甲烷二异氰酸酯(MDI)作为扩链剂合成聚(D,L)-乳酸/羟基磷灰石(PDLLA/HA)复合材料,通过扫描电镜(SEM)观察该复合材料的断面形态。结果:当温度为100℃、保温保压时间45min时,该复合材料的弯曲强度可获最大值,继续增加保温保压时间,弯曲强度基本保持不变。而弯曲模量随保温保压时间的增加变化不大;当MDI中的NCO基团与PDLLA中的OH基团摩尔比为1∶1时,材料力学性能达到最佳;SEM观察显示取向后材料纵向纤化程度高,弯曲断面有大量纤维尾端。结论:模压挤出可使复合材料产生取向结构,MDI扩链可提高复合材料的相对分子质量,两种手段都能显著提高复合材料的力学性能,而且成型加工条件和MDI用量对聚(D,L)-乳酸/羟基磷灰石(PDLLA/HA)复合材料的力学性能和形态结构有显著影响。
AIM: To investigate the effect of compression-extruding conditions and methylenediphen yl diisocyanate(MDI )content on mechanical properties an d morphology of poly (D,L-lactide)/hydroxyapatite composite(PDLLA /HA)by utilizing self-desi gned compression-extruding equipment.METHODS:Poly(D,L-lactide)(PDLLA)an d MDI chain-extending PDLLA /HA were prepared in the presence of stannous(Ⅱ )octoate respectively,and scanning electron microscopy(SEM)was used to obser ve fracture surfaces of composites.RESULTS:Bending strength of PDLLA/HA compo site got maximum at pro-cessing temperature of 100℃,heat an d pressure pre servation time of 45mi n and its bending strength almost unch anged with furth er increasing time o f heat and pressure preservation.But its b ending modulus had no influence with in-creasing time of heat and pressure pr eservation.Whe n molar ratio of -NCO group in MDI to -OH group in PDLLA was 1:1,both bend ing strength and bending modulus of PDLLA/HA composite got the maximum.SEM res ults showed that there were a lot of parall el oriented structure of fibrils to l ong axis in bending fracture surface and longitudinal split surface.The compression-extruding techniq ue compelled PDLLA/HA composite to form o riented structure and MDI chain-extending can increase molecular weight of PDLL A/HA composite,so its mechanical properties are enhanced.The compression-ext rudi ng co
出处
《中国临床康复》
CAS
CSCD
2004年第2期250-251,T004,共3页
Chinese Journal of Clinical Rehabilitation
基金
国家自然科学基金重点资助项目(59932050)~~
