聚乳酸共混物界面调控及其在熔融沉积成型中的应用

The project focus on the enhance of interfical adhension between the layers of polylactic acid (PLA) based fused deposition modeling (FDM) products.The Diels-Alder (D-A) reaction and its reverse reaction were used to modify the interfical adhension of PLA blends.The micro interfacial mechanics test combined with temperature fileds was used to explore the adhesive contact between polymer blends under different temperatures. The substrates of D-A reaction based on modified PLA and polyethylene glycol (PEG) were prepared. Recombination and rearrangement of chemical bond of PLA/PEG/ acrylonitrile-butadiene-styrene copolymer (ABS) molecular chains were obtained by the D-A reaction and its reverse reaction.Associated with rheological behavior, morphology, crystalline structure and macro mechanical properties,the mechanism of improvement in interfical adhension between the layers of PLA FDM products were fully discussed from the point view of different levels.This project will expand the application of D-A reaction in polymer processing field, also it will provide a new way for preparing high performance polymer based FDM product.

本项目针对聚乳酸（PLA）基熔融沉积成型（FDM）制品层间结合不足的问题，拟通过Diels-Alder（D-A）反应及其逆反应调控FDM中改性PLA共混物的界面结合。项目拟合成基于D-A反应的改性PLA、聚乙二醇（PEG）原料，研究D-A反应及其逆反应调控FDM中改性PLA、PEG与丙烯腈-丁二烯-苯乙烯共聚物（ABS）分子链化学键的结合、断裂与重新再结合；将控温热台与微观力学表征手段相结合研究温度状态不同的PLA共混物间界面结构演变规律；同时结合流变、结晶结构、形貌及宏观力学性能等研究，从微观、介观、宏观不同尺度揭示PLA共混物FDM成型制品界面结合的调控机理。该项目的实施将拓展D-A反应在聚合物共混物加工领域的应用，为改善聚合物基FDM制品性能提供新思路。

聚乳酸是目前商品化较多的熔融沉积成型（FDM）材料，广泛应用于生物医药、组织工程等领域。然而由于聚乳酸韧性差、冲击强度低，FDM层间界面结合不足，限制了其在增材制造领域的应用;目前一般通过共混、复合等方式改善聚乳酸材料的结构从而提高力学性能。丙烯腈-丁二烯-苯乙烯共聚物（ABS）基于其抗冲击性强、易加工等优点，近年来被广泛的应用于非降解材料的增材制造;将聚乳酸和ABS共混合金化，将可能获得刚韧平衡的高性能材料。本研究从聚乳酸共混物的改性入手，通过化学物理手段相结合，改善了用于熔融沉积成型的聚乳酸共混物的加工和使用性能，同时提出利用Diels-Alder反应调控方法使得材料自身重排和再结合实现界面结合改善，从而可以克服由于聚乳酸和ABS较高的分子量在加工中易发生相分离导致不相容。相较于常用的改变界面结合的方法具有效率高、操作简便、制备过程中无需添加额外助剂等优势。进一步的，研究拓展了聚合物3D打印的应用体系，在组织工程等领域进行了初步探索，为后期的进一步拓展性工作奠定了基础。