高频电场与正应力场协同作用聚烯烃低温塑化机理研究

A new method of polyolefin plasticizing processing in low temperature by synergizing high-frequency electric field with positive stress field is proposed in this study. That is non-polar polyolefin materials will generate certain local deformation, defects, forming a number of micro-interface under larger enough positive stress field. And the interface is electrode since the molecular chains have been distorted, dislocation, or rupture, which will realize the polyolefin plasticizing in low temperature under the thermal effect of high-frequency electric field. The association model based on polyolefin solid micro-interface and dielectric loss coefficient under positive stress field as well as the dynamic models of polymer plasticizing and conveying in low temperature by synergizing high-frequency electric field with stress field will be established in this subject. The influence rules of polyolefin solid micro-crack extension on the dielectric loss coefficient of micro-interface under positive stress field will be revealed. The polyolefin plasticizing and conveying mechanism in low temperature by synergizing multi-field such as high-frequency electric field, positive stress field, processing temperature and so on will be explored. A self-designed laboratory equipment of polymer plasticizing processing in low temperature by synergizing high-frequency electric field with stress field will be used to investigate the influencing mechanism of processing parameter on the comprehensive physical properties of the polyolefin plasticizing product processed in low temperature. The controllable processing of polyolefin by synergizing high-frequency electric field with positive stress field will be realized. Furthermore, the study will promote the development of basic theoretical research on polymer processing in low temperature.

申请人提出高频电场协同正应力场聚烯烃低温塑化加工新方法：非极性聚烯烃材料在足够强的正应力场作用下局部将产生变形、缺陷而呈现众多微界面，这些微界面由于分子链被扭曲甚至错位、断裂而呈电极性，进而实现聚烯烃在高频电场热效应下的低温塑化过程。课题将构建正应力场作用下聚烯烃固体微界面介电损耗系数关联模型及聚合物在高频电场与应力协同作用下低温塑化输运动力学模型，揭示正应力场作用下聚烯烃固体微裂纹扩展对微界面介电损耗系数的影响规律，探索高频电场、正应力场、加工温度等多物理场协同作用聚烯烃低温塑化输运机理，利用自行研制聚合物高频电场与应力场协同低温塑化加工实验设备，研究加工参数对聚烯烃低温塑化产物综合物理性能的影响机制，实现高频电场与正应力场协同低温塑化加工过程调控。推动聚合物低温塑化加工领域基础理论研究的发展。

本项目针对当前聚烯烃加工存在低效率、能耗高、制品分子链降解严重等问题，提出了一种高频电场协同正应力场聚烯烃低温塑化加工新方法：非极性聚烯烃材料在足够强的正应力场作用下局部将产生变形、缺陷而呈现众多微界面，这些微界面由于分子链被扭曲甚至错位、断裂而呈电极性，进而实现聚烯烃在高频电场热效应下的低温塑化过程。针对上述聚烯烃加工新方法，项目组开展了高频电场与正应力场协同聚烯烃低温塑化成型机理研究，主要内容包括：正应力场作用下聚烯烃固体微界面介电损耗系数关联模型研究；高频电场与正应力场协同聚烯烃低温塑化输运动力学研究；高频电场与正应力场协同聚烯烃低温塑化过程调控机理研究。通过建立正应力场作用下聚烯烃固体微裂纹物理模型，并得到了模型的解析解，揭示微裂纹产生与扩展和微界面形成机理，并研究了微裂纹与介电性能的关联机制；针对不同的正应力场，自行设计研制了两套实验设备：高频电场与平板正应力场协同塑化设备、高频电场与辊压正力场协同加工设备；利用自行研制的实验装置，实现了聚烯烃高频电场协同正应力场低温塑化加工，并建立了正应力场强度、高频电场强度、作用时间、作用温度等参数与聚烯烃塑化效果的关联模型；同时构建了高频电场与正应力场协同作用下多种聚烯烃热响应特性及温升模型，证实了聚烯烃在耦合场作用下的热响应与结晶形态、微界面结构、热力学性质等因素相关；在上述研究的基础上，项目还进一步利用新的加工方法对聚合物纳米复合材料的塑化加工效果进行研究，建立了复合体系中微界面结构演变与介电损耗关联机制，发现耦合中可实现纳米填料取向增强和两相界面增容。本项目揭示了高频电场与正应力场协同作用对聚烯烃材料塑化过程的影响机制，实现聚烯烃等聚合物材料低温塑化可调控加工，旨在聚合物加工领域开拓一种低温加工的新途径，在基础理论和应用领域都具有十分重要的意义。