Polymer materials have been used as electrical insulating materials for a long time. With the needs of different application fields and to further broaden the application scope of polymer materials, some polymer materials have been endowed with a certain degree of conductivity to become conductive polymer materials. The first highly conductive polymer material was iodine-doped polyacetylene. Later, conductive polymer materials such as polypyrrole, polyparaphenylene, polyphenylene sulfide, and polyaniline were developed.
〔1〕. Since these conductive polymer materials have a yoke bond structure and are mainly processed by chemical methods, they are often called intrinsic conductive polymer materials. However, this type of material has poor stability and reproducibility, a narrow conductivity distribution range, high cost, and difficult processing. It has not yet entered the practical stage of mass production
[2]. The difficulties encountered in the application of intrinsic conductive polymer materials are difficult to solve in the short term, prompting people to turn to research and development of conductive polymer composite materials. Conductive polymer composite materials are multi-phase composite conductive systems formed by using polymer materials as the matrix, adding conductive functional bodies, and processing through dispersion compounding, lamination compounding, and surface conductive film formation. It has received widespread attention due to the easy availability of raw materials, relatively simple process, low cost, resistivity that can be adjusted within a wide range, a certain degree of reprocessability and some excellent properties of polymer matrix materials.
The research work on conductive polymer composite materials mainly includes:
① Theoretical research on the conductive mechanism of composite materials and the theoretical research on the special effect mechanism.
② Experimental research on developing new materials using different methods.
③ Experimental research on material application.
Theoretical research on the conductive mechanism of conductive polymer composites usually includes the formation of conductive paths and the conductive mechanism after the conductive paths are formed. The former studies how the conductive functional body added to the polymer matrix can achieve electrical contact and spontaneously form a conductive path as a whole under given processing conditions. This is a macroscopic self-organization process. The latter mainly involves the microscopic process of carrier migration after the conductive path or part of the conductive path is formed. Obviously, whether they are macroscopic processes or microscopic processes, they are restricted by various factors such as the geometric topology, thermodynamics and kinetics of the composite system. Therefore, on the one hand, the theoretical research work on conductive polymer composites is diverse and complex; on the other hand, there are varying degrees of differences with experimental results, and many theoretical results are often not universal. The main methods used in experimental research on new materials are: component modification (changing the type of matrix, changing the type of conductive functional body). Modification of the physical properties of the whole or components (magnetization, grafting, heat treatment, crystallization, impregnation). Structural modification (plate, laminated, foam). Shape modification of conductive functional bodies (granular, spherical, hollow, fibrous), etc. Applied research includes theoretical and experimental research to solve various practical problems according to application conditions and specific requirements.