聚乳酸/聚丁二酸丁二醇酯两相高粘流体共连续相形成与控制研究

To relieve environmental pollution and the energy crisis, environmental friendly and degradable materials has been used to replace the traditional petroleum-based plastics. Polylactic acid (PLA) is widely used in many fields, which is considered to be a good substitute for petroleum based polymers. However, low impact toughness of PLA severely restrict its application. Polymer blending can be used to improve toughness of PLA. Performance of the polymer blend is generally determined by its phase morphology. Stress transmission loss does not exist in interface of the continuous phase structure, which can significantly increase material performance. This project plans to blend poly (butyl diacid butyl glycol ester) (PBS) with good toughness and PLA, and apply shear flow field provided by homemade morphology control instrument to adjust the phase structure of PLA/PBS highly viscous fluid, and finally co-continuous phase structure of PLA/PBS system of will be obtained. Then through regulating the viscosity ratio and composition ratio of PLA/PBS to control co-continuous phase fine structure, to finally get high-performance PLA/PBS blends. By investigation of phase morphology evolution law of PLA/PBS viscous fluid system under shear flow field, regulation of co-continuous phase fine structure in PLA/PBS viscous fluid system, and evaluation of morphology and performance of PLA/PBS viscous fluid system, to reveal relationship between processing conditions - phase structure - performance. To applied theoretical guidance and technical support for high-performance full biodegradable PLA/PBS materials, and finally to expand application field of biodegradable materials.

为缓解环境污染和能源危机，用环境友好、可降解的材料替代传统的石油基塑料成为趋势，聚乳酸（PLA）应用广泛，是石油基聚合物的良好替代品。但PLA冲击韧性较差，应用领域受到严重限制。聚合物共混能改善PLA韧性。聚合物共混物的性能决定于其相态结构，共连续相结构不存在界面处的应力传递损失，可使材料性能大幅提高。本项目拟采用韧性较好的聚丁二酸丁二醇酯（PBS）与PLA共混，并通过自制的形态结构控制仪提供剪切流动场调整PLA/PBS高粘流体体系相态结构，获得共连续相结构，通过粘度比、组成比调控共连续相精细结构，最终得到高性能化PLA/PBS材料。通过系统研究剪切流动场下PLA/PBS高粘流体体系的相形态演变规律，共连续相精细结构的调控，及PLA/PBS体系的相态结构、性能评价，揭示加工条件-相态结构-性能的关系，为得到高性能化的可全生物降解PLA/P/PBS材料理论指导与技术支支持，扩大其应用领域。

为缓解环境污染和能源危机，用环境友好、可降解的材料替代传统的石油基塑料成为趋势，聚乳酸（PLA）应用广泛，是石油基聚合物的良好替代品。但PLA冲击韧性较差，应用领域受到严重限制。聚合物共混能改善PLA韧性。聚合物共混物的性能决定于其相态结构，共连续相结构不存在界面处的应力传递损失，可使材料性能大幅提高。.本项目采用韧性较好的聚丁二酸丁二醇酯（PBS）与PLA共混，并系统地研究了PBS/PLA共混聚合物高粘流体在复杂的剪切流动场、温度场等外场下各相的运动、分布和演变规律。通过“挤出热拉伸-二次模压”的加工技术，在拉伸流动下到了PBS/PLA共混物原位纤维化结构，实现了复合薄膜力学性能和气体阻隔性能的增强，阐明了复合薄膜的气体阻隔性能提高的机理；通过振动剪切注塑（OSIM）技术获得了PBS/PLA高粘共混体系多层次的取向结构，揭示实际加工过程中剪切流动场对PBS/PLA高粘流体各相的运动及分布的影响规律，实现了对PBS的同时增强增韧，阐明了多层次取向结构对PBS增强增韧的机理。此外，拓展研究了剪切振动场及温度场下PLA熔体的晶体结构和性能，为耐热PLA制品的制备提供了理论和技术指导。