A new kind of flexible conductive polymer composites with positive temperature coefficient effect

Conductive Polymer Composites (CPCs) exhibit significant application potential in the fields of temperature sensing and self-regulating heating for electronic devices. Leveraging their unique Positive Temperature Coefficient (PTC) effect, these materials can effectively serve as overheat protection mechanisms. However, conventional CPCs are predominantly based on rigid, highly crystalline matrices. This characteristic not only restricts their application in flexible electronics but also results in relatively high Curie temperatures that fail to meet the requirements for precise thermal control at room temperature. To address these limitations, this study prepares and investigates a novel flexible, room-temperature polymeric PTC material. The material was prepared by blending graphite powder (GP) with ethylene vinyl acetate (EVA)/polystyrene (PS), with PS acting as a support material to provide flexibility. In addition, the positive temperature coefficient (PTC) characteristics and mechanical properties of the materials were experimentally investigated. The results show that the prepared composites have good PTC properties and flexibility. The flexibility of the new PTC material is optimal when the graphite powder content is 17% and the mass ratio of EVA/PS is 3:2. At the same time, changing the filler particle size can greatly affect the room temperature thermal conductivity and PTC strength of the material.