Study Of Polymer PTC Conductive Composite

Organic PTC composite is a novel functional material with important research value, witch is used in the field of self-control heating cable, over-current protecting component, electromagnetism shield material and sensor etc.But nowadays many theory and practical problem about organic PTC composite is still not settled, witch focus in the conductive mechanism, enhance of PTC intensity, elimination of NTC phenomenon, and improvement of stability and repetition.According to the condition of research and application about organic PTC composite at home and abroad, polymer/carbon black conductive composite was studied detail in this paper. Through the research of crosslinking of matrix resin, heating treatment of composite and mixing of different polymer, we draw some conclusions: 1,Percolation theory can explain the phenomenon of the jump of resistance when the content of CB reach a critical volume; 2,Based on ohm conduct theory , abounded to the percolation the WBIBULL statistical theory and other theory ,an adapted theory was obtained to explain the jump of resistance and the other phenomenon; 3,The NTC phenomenon was eliminated by crosslinking the matrix of conductive composite, at the same time the stability of composite was improved. With the increase of silane content, the content of gelatin increased continuously and NTC phenomenon disappeared gradually. when the silane content reach a certain volume, the NTC phenomenon was eliminated completely, at one time, the content of gelatin keep stable.4,Heating treatment can improve PTC characteristic of composite and increase PTC intensity. When the temperature and time ofheating treatment are 120℃ and 30h,respectively, the result is best. 5,new composite filler/PP composite has double-PTC effect, at the same time, it's stability is fine...