【作者】 张宁；

【导师】 瞿金平；

【作者基本信息】 华南理工大学 ， 材料加工工程， 2013， 博士

【摘要】 聚合物的成型加工设备和其成型加工方法对于聚合物在塑化输运过程中由固体相到熔体相的形态演变和聚合物的宏观性能的表现有着密切的关系。不同于螺杆挤出，瞿金平教授发明的体积拉伸形变塑化挤出机的塑化输运过程中聚合物由固体相到熔体相的形态演变具有自身特点，这种特点和规律影响着聚合物的分散混合效果，并最终决定着挤出制品的性能。因此，体积拉伸形变作用下物料熔融过程形态演变及其分散混合特性具有重要的价值和意义。这对于深化理解体积拉伸形变控制的高分子材料塑化输运方法具有重要的意义，为进一步完善物料在塑化输运过程中的机理和模型奠定了基础。从单组分物料和双组分不相容共混物两个角度系统地分析了体积拉伸形变下聚合物形态演变过程和规律。利用冷却实验分析多种单组分聚合物熔融过程中的形态演变，并且深入研究了加工工艺参数对于HDPE形态演变过程的影响。对双组分不相容共混物，一方面利用冷却实验分析了共混物的形态演变过程，另一方面分析了每组塑化输运单元内完全熔融的共混物微观形貌变化和分散混合特性。此外，对PA/TPO和PP/PA共混物微观形貌进行了分析，统计了分散相的粒径分布情况；分析了纳米粒子CaSO₄和TiO₂填充PBS体系共混物的微观形态、结晶、力学、热学等性能。研究结果表明，体积拉伸形变作用下熔融过程聚合物形态演变依次出现：多熔膜，蜂窝，熔池固体床和悬浮液等四个特征，其对多组分共混体系的分散混合特性具有很好的促进作用；体积拉伸形变作用下聚合物物料颗粒的塑性变形、熔融和形态演变过程、以及界面变化和演变过程产生了大量的塑性耗散能（PED）、摩擦耗散能（FED）和黏性耗散能（VED），这些能量是聚合物形态演变过程重要的热量来源；转速对于体积拉伸形变作用下物料熔融过程形态演变具有重要影响；体积拉伸形变塑化挤出机对于物料的挤出加工具有正位移输送的特性，停留时间和熔融时间短，熔融塑化效率高，热机械历程短。对挤出PA/TPO和PP/PA共混物的微观形貌研究发现，体积拉伸形变塑化输运过程对于不相容体系共混物具有良好的分散混合效果，分散相主要呈现液滴的形式；塑化输送单元容腔容积的体积拉伸形变作用能够促使共混物中分散相液滴的破碎和均匀分布；体积拉伸形变塑化挤出机在加工黏度比大的不相容体系共混物时具有较好的分散混合效果，物料黏度特性依赖小；当基体为高黏度物料，分散相为低黏度物料时，分散相液滴尺寸更小，分散混合效果更好。对挤出CaSO₄和TiO₂填充PBS体系共混物的分析测试表明，体积拉伸形变支配的塑化输运过程对于纳米粒子填充PBS共混物具有较好的分散混合效果，纳米粒子作为刚性粒子对于PBS的力学性能有了一定的提升，同时纳米粒子的加入起到热屏障的作用，提升共混物热稳定性。更多还原

【Abstract】 Polymer processing equipment and processing method have a close relationship withpolymer’s performance and morphological evolution from solid state to melt state. Unlikescrew extrusion, the morphological evolution has its own characteristics in volumeelongational deformation plasticizing transporting process invented by Professor Qu, whichinfluencing the dispersion and mixing effect and determining the performance of extrusionproducts. Therefore, the research on polymer morphological evolution in melting process anddispersion and mixing characteristics have important value and significance. It is significantto deepen the understanding of polymer material plasticizing conveying method under volumeelongational deformation, and it laid the foundation to further improve mechanism and modelon the process of plasticizing and conveying polymer.The morphological evolution was systematically analyzed under volume elongationaldeformation from the perspective of single component polymer and two componentimmiscible blends. Through the cooling experiment we analyzed the morphological evolutionin melting process form several kinds of single component polymer, and further researchedthe influence of process parameters for HDPE morphological evolution. For two componentimmiscible blends, on the one hand, using cooling experiment we analyzed the blendmorphological evolution, on the other hand, we analyzed completely melt blend’smicromorphology change and dispersion and mixing characteristics. In addition, PA/TPO andPP/PA blends’ micromorphology were analyzed, and the size distribution of the dispersedphase was estimated; micromorphology, crystal structure, mechanical and thermal propertiesof PBS filled with CaSO₄and TiO₂nanoparticles were analyzed.It was shown that under volume elongational deformation polymer’s morphologicalevolution have four characteristics sequentially including multi melt film, honeycomb, moltenpool solid bed and suspension, promoting the dispersion and mixing characteristics for themulticomponent blend system. Under volume elongational deformation much plastic energydissipation, friction energy dissipation and viscous energy dissipation were produced bypolymer’s plastic deformation, melting and morphological evolution, and interface changesand evolution process, which are important heat resources for polymer’s morphologicalevolution. The rotation speed is important for polymer’s morphological evolution undervolume elongational deformation. And the characteristics of positive displacement conveying,short residence time, short melting time, high molten plasticizing efficiency, short thermalmechanical process were shown in the volume elongational deformation plasticizing extruder. It was found that the volume elongational deformation plasticizing and conveyingprocess has good dispersion and mixing effect for the immiscible blends from the study on thePA/TPO and PP/PA blends’ micromorphology. Dispersed phase was mainly presented in theform of droplets. Dispersed phase in the form of droplets was easily broken and evenlydistributed under volume elongational deformation of the cavity volume in the plasticizingand conveying unit. Volume elongational deformation plasticizing extruder has gooddispersion and mixing effect on the immiscible blends with large viscosity ratio, and littledependence on the viscosity of material. The droplet size of the dispersed phase is smaller andthe dispersion and mixing effect is better with the matrix of high viscosity and the dispersedphase of low viscosity.It was shown that the volume elongational deformation plasticizing and conveyingprocess has good dispersion and mixing effect for PBS filled with nanoparticles from theanalysis and test of CaSO₄/PBS and TiO₂/PBS. The nanoparticles acted as rigid filler toenhance the mechanical properties and thermal barrier to promote the thermal stability.更多还原