可生物降解聚合物物理发泡研究进展

Advances in Physical Foaming of Biodegradable Polymers

摘要:

对比传统的聚合物发泡材料，可生物降解聚合物具有绿色环保和持续性的优点，广泛应用于农业、食品包装、生物医药领域中。通过物理发泡工艺制备的可生物降解聚合材料除具有自身的特性外，还兼具轻量化、绝热性和缓震性等优点，是传统石油基聚合物泡沫材料的潜在替代品。然而，可生物降解聚合物普遍存在分子链结构单一、熔体强度低和制备成本高等问题，并且在物理发泡过程中易发生泡孔破裂或熔并，从而导致基体收缩，泡孔结构难以保持。基于可生物降解聚合物物理发泡工艺的机理，对不同物理发泡方法进行了分类，并针对各类工艺的特点进行了全方位的阐述。随后，围绕几种典型的可生物降解聚合材料进行了发泡行为及参数关系的讨论，介绍了不同材料对发泡工艺及发泡剂的选择依据，综述了发泡条件对膨胀倍率和泡孔尺寸的影响规律。此外，对多种可生物降解聚合物在发泡过程中存在的问题给出了相应的解决方案，介绍了可生物降解聚合物泡沫在食品包装、电子电器、生物医疗材料领域中的功能应用，总结了发泡工艺、聚合物结晶行为及改性方法对可生物降解聚合物发泡过程的影响。最后，指出了可生物降解聚合物泡沫在未来发展中的方向与挑战。

关键词:可生物降解聚合物;物理发泡机理;熔体强度;泡孔结构;材料改性;功能应用;绿色环保

Abstract:

Compared to traditional polymer foam materials， biodegradable polymers have the advantages of being green， environmentally friendly， and sustainable， and are widely used in agriculture， food packaging， and biomedical fields. Biodegradable polymer materials prepared by physical foaming process not only have the above characteristics， but also have the advantages of lightweight， thermal insulation， cushioning and so on. They are potential substitutes for traditional petroleum based polymer foam materials. However， biodegradable polymers generally have limitations such as single molecular chain structure， low melt strength， high preparation cost， and are prone to cell rupture or fusion during physical foaming， resulting in matrix shrinkage and inability to maintain cell structure. This work takes the process mechanism of biodegradable polymer physical foaming as the starting point， classifies different physical foaming methods， and comprehensively elaborates on the characteristics of each category of processes. Subsequently， discussions were conducted on the foaming behavior and parameter relationships of several typical biodegradable polymer materials. The selection criteria for foaming processes and foaming agents for different materials were introduced， and the influence of foaming conditions on expansion rate and cell size was summarized. In addition， corresponding solutions were given to the problems existing in the foaming process of various biodegradable polymers， and the functional applications of biodegradable polymer foam in food packaging， electronic appliances， and biomedical materials were introduced. Finally， the effects of foaming process， polymer crystallization behavior and modification methods on the foaming process of biodegradable polymer were summarized， and the direction and challenges of biodegradable polymer foam in the future development were proposed.

Key words:biodegradable polymers;physical foaming mechanism;melt strength;cell morphology;modification;application;eco-friendly