Current Research and Patents of Polymer Foaming

Background: Since the rapid development of polymers in the 1920’s, polymer products have become a necessary part of people's lives. Supercritical fluid technology was gradually introduced in this field. With the emergence of new technologies, methods, and equipment, the supercritical fluid technology has rapidly developed in the field of polymers and displayed a broad application perspective. Objective: The research progress of supercritical fluid-assisted polymer foaming, including equipment improvement, polymer composition ratio, and foaming process, and the influence of these processes on polymer foaming materials is reviewed here. Methods: Patents and research progress of supercritical fluid assisted polymer foams were reviewed. The advantages and disadvantages of various patents are analyzed in terms of cell structure, mechanical properties, surface quality, processing performance, and cost. Results: The foaming equipment and the manufacturing process of polymer foaming materials were retrospected, in order to improve the quality and application prospect of foaming composites. Conclusion: The preparation technology of supercritical fluid polymer foams has attracted wide attention. In recent years, patented technology has enabled us to use the supercritical fluid polymer foaming materials. There are some problems in the supercritical fluid foaming in terms of mechanical properties, cell structure, cell size, and processing technology, therefore, more equipment and patents are needed to solve these problems in the future.