Microstructure Effect of Injection Molded Nanoparticle/Polymer Composites on their Resistivity

Abstract

Although the progress has been achieved in conductive Nanoparticle/Polymer Composites(NPC), but there are many problems to be solved before their commercial application in a large scale, especially on their processing technology. The barriers include the dispersion of nanoparticle, the effect of nanoparticle concentration and interface on the overall properties of materials. In order to improve the application of NPC, the microstructural effect of injection molded NPC on its resistivity was investigated to build the relationship between the processing conditions and the properties in this paper. Composites used in the experiment were carbon black(CB)/polypropylene(PP). The microstructures of the injection molded parts at different positions were investigated with Scanning Electrical Microscope, and corresponsive properties were tested. The results showed that the distribution of CB nanoparticles changed with the injection pressure and had significant effect on the conductivity of the part. With the increase of injection pressure CB particles strongly oriented towards the flow direction of the polymer and thickness of oriented layer increased, which improve conductivity of the composites. The results also showed that crystallization was enhanced because of existence of nanoparticles, which should have increased the mechanical properties of the composite and decreased its resistivity because of the interfacial action between CB particles and polymer matrix.