Preparation Of Polymer-based Conductive Composites And Particle Size Distribution Of The Technical Studies

The polymer matrix high conductive composites not only has good machinery and mechanics capability , but also has adjustive electricity , and easy -shaped,lower cost ,there fore becomes a hot research in the field of functional polymer materials. At present, this kind of materials is widely used for the facsimile electrode board , composite bipolar plates for polymer electrolyte fuel cell and guards against static electricity outer covering cover board , electromagnetic wave absorption part and electromagnetic shielding material etc.In this paper , the molded composite-method at high temperature was adopted,by employing the self-control experiment shaping device,to prepare the polymer matrix high conductive composites with polybenzoxazine,polyimides as the resin base,the graphite and carbon fiber as electrical fillers. The effect of Solvent-treatment,oxidated by concentrated nitric oxide at room temperature and treated by hot gaseous oxidation of conductive fillers,and different fillers mixed on the volume resistivity and mechanical properties of composites was investigated.By measuring the parameters such as resistivity and winding intensity of the samples, we found the surperficial epoxy resin of graphite filler by acetone solvent -handling had been brushed off,the compatibility of resin was improved. When the graphite filler was oxided at high temperature,the graphite particles' sandwich expanded,contacts the formation electric conduction channel mutually generally leading greatly the width of cloth to raise,but mechanics capability was reduced. The conductivity of the conductive composites got big to raise,by oxiding the carbon fiber in dense nitric acid of liquid phase at normal temperature , but the mechanics capability has going up and down of different level .Counting by way of building the specific conductance model,and we found that the microstructure of graphite particle shape was different from the grape- stringtrain structure of carbon black particles, and the piece layer structure was perpendicular in the electric field direction . The resistivity and mechanics capability of composites samples by mixing conductive filler graphite and the carbon fiber , and grading different granul diametre graphite fillers were researched. We founded the conductivity of composites was influenced by mixing-mode, and two granul diameter grading mode of conductive filler maybe the most excellent mode in the proportion . The interface combination of compoites was analysed by adopting DMA's ( dynamic mechanics mechanical analysis ) , and found that the energy storage modulus and the loss modulus of the composites by mixing graphites carbon fiber to the composites raised largely, and the compatibility was improved. Comprehensive study ,we have prepared polyimide / graphite and polyimide / graphite / carbon fiber high conductivity composite materials of maximum bending strength 70.65MPa, volume resistivity of 10^-3～10^-2Ω·cm.Therefore, handling to electric conduction filler carries on the necessary surface treatment, mixing the different kind conductive fillers and grading the particles of different granul diametres ,we can gain the excellent the polymer matrix high conductive composites with good conductivity and mechanics capability.