聚合物微纳多尺度分布泡孔结构的流变调控与形成机理

The rheological property of polymer melt was significantly changed by the supercritical fluid in the microcellular injection molding process, which lead to the difficulty to mold based on the traditional theory. To quantitative tune the cell structure of the final foam specimens, a setup which is used to monitor the temperature and pressure of the polymer melt online in the mold cavity will be designed to get the essential parameters of the viscosity of the polymer-gas phase and also the cell morphology. This visualization system is equipped with the optical system, thermo and pressure sensor to record the flow behavior and instant value of the temperature and pressure. The viscosity model will be revised to take account the gas phase in the polymer melt. It will be helpful for the exploration of the relationship between rheological property and cell structure (cell size and cell density), and the formation mechanism of cell structure and distribution in multi-scale which was fabricated in our previous study. Meanwhile the relationship between process parameter, rheological property, and cell structure will be investigated to theoretical guide the fabrication of the porous polymer scaffold in multi-scale cell distribution.

微孔发泡注射成型聚合物熔体的流变特性在超临界流体作用下会发生显著改变，从而带来按照传统加工理论无法解决的技术难题。为实现泡孔结构的定量化严密调控，本项目从前期制备和发现的双尺度模式分布泡孔结构而引发的理论和工艺问题出发，通过研制可在线测量气熔混合物的关键流变特性参数和观测泡孔形态演变的可视化实验装置，从而定量获得聚合物熔体/气泡两相体系在模具型腔流动过程中不同位置的实时温度、压力数据，以及实况记录气熔混合物的流动行为和定量采集泡孔形态演变数据。进而修正和表征气熔混合体系的粘度理论模型，进而探明聚合物气熔混合体系流变特性对泡孔尺寸和密度的影响规律和其定量化调控机制。项目将系统开展发泡成型工艺参数、泡孔长大阶段气熔混合物的流变特性与泡孔形态演变的关系研究，解决微孔发泡注射成型泡孔尺寸和密度难以调控、制品一致性不好等加工难题，为制备微纳多尺度分布泡孔结构的三维可降解多孔生物支架提供理论指导。

开展聚合物气熔混合体系流变特性和发泡型工艺参数对泡孔形态与结构演变的影响规律研究，对于制备理想三维可降解多孔材料具有重要的理论指导意义。项目首先研制了可在线测量气熔混合物的关键流变特性参数和监测泡孔形态演变的可视化实验装置，实现了微孔注塑发泡过程的在线监测，为研究泡孔成核与长大理论提供了新手段；研究了二次发泡工艺和纳米粒子对发泡过程泡孔成核作用机理和性能增强作用，制备了皮芯结构相对均匀、泡孔形态与性能优良的微孔发泡注射成型制品；系统研究了生物可降解聚乳酸/聚已内酯（PLA/PCL）等共混体系的微孔发泡注射成型工艺与性能调控方法，探究了该共混体系流变特性与制品泡孔形态之间的关系。项目成果对微纳多尺度分布泡孔结构的可降解聚合物多孔材料的制备技术具有重要的理论与实践指导意义。相关成果发表SCI论文7篇（其中一区论文1篇，二区论文2篇），EI论文2篇，出版英文专著（章节）1部。