摘要
通过双螺杆挤出机将β成核剂(TMB-5)和乙烯-乙烯醇共聚物(EVOH)熔融共混,制备β-EVOH,采用微纳层叠共挤出装置,将β-EVOH相在全同立构聚丙烯(iPP)相中原位微纤化,构筑β成核剂选择性分布,制备了β-EVOH/iPP原位微纤复合材料。在流动场、微纤相及β成核剂选择性分布共同作用下,考察了β-EVOH含量对复合材料多尺度微观结构及结晶性能、力学性能、阻隔性能的影响。结果表明,在微纳层叠共挤出装置强烈的剪切-拉伸流动场作用下,所选含量范围(质量分数5%~50%)的β-EVOH均能在iPP中形成微纤,且形成片层状微纤与圆柱状微纤并存的相形态结构;在β-EVOH/iPP原位微纤复合材料原始挤出样品中只形成α晶,只有当样品在高温熔融,消除了流动场的作用,同时提供β成核剂从纤维相向界面迁移的动力,才能在iPP重结晶时形成β晶。随着β-EVOH相含量的增加,β-EVOH/iPP原位微纤复合材料的拉伸强度先升高后变化不大,断裂标称应变先增大后减小,水蒸气透过量逐渐减小,这主要由相形态结构的差异引起的。
β-nucleating agent(TMB-5)and ethylene-vinyl alcohol copolymer(EVOH)were melt blended in a twin-screw extruder for preparing β-EVOH.The micro-nano lamination co-extrusion device was employed to in-situ micro-fiberize the β-EVOH in the isotactic polypropylene(iPP)phase,constructing a selective distribution of β-nucleating agents and preparing the β-EVOH/iPP in-situ micro-fiber composites.Under the combined effects of the flow field,micro-fiber phase,and selective distribution of β-nucleating agents,the effects of β-EVOH contents on the multi-scale microstructure,crystallinity,mechanical properties,and barrier performance of the composites were investigated.The results indicate that under the strong shear-stretching flow field of the micro-nano lamination co-extrusion device,β-EVOH within the selected content range(5wt%-50wt%)can form micro-fibers in iPP,and the coexistence of lamellar and cylindrical micro-fiber phase morphology structures is formed.In the original extruded samples of β-EVOH/iPP in-situ micro-fiber composites,onlyα-crystals are formed.Only when the samples are melted at high temperatures to eliminate the effect of the flow field and provide the driving force for β-nucleating agents to migrate from the fiber phase to the interface,β-crystals are formed in iPP during iPP recrystallization.With the increase of the β-EVOH phase content,the tensile strength of the β-EVOH/iPP in-situ micro-fiber composite first increases and then changes little,the nominal strain at break first increases and then decreases,and the water vapor transmission gradually increases,mainly due to the differences in phase morphology structures.
作者
蔡佩伶
罗珊珊
孙静
CAI Peiling;LUO Shanshan;SUN Jing(Guizhou Provincial People’s Hospital,Guiyang 550002,China;Guizhou Material Technology Innovation Base,Guiyang 550014,China)
出处
《工程塑料应用》
北大核心
2025年第6期146-152,共7页
Engineering Plastics Application
基金
国家自然科学基金项目(52063007)
贵州省科技计划项目(黔科合成果[2024]一般044)。
关键词
聚丙烯
原位微纤
成核剂选择性分布
结晶性能
力学性能
阻隔性能
polypropylene
in-situ micro-fiberization
selective distribution of nucleating agent
crystallinity
mechanical property
barrier property
