| With the development of science and technology, people have more and more requirements for the performance of the conductive composites. Traditional conductive composites can’t be adapted to the requirements of some areas, the flexible conductive composites were emerged as the times require, theyreceived extensive attention and research. Flexible conductive composites is a new material, both excellent conductivity and good mechanical properties. Carbon nanotubes and graphene is often used as conductive filler. Carbon nanotubes and graphene has excellent performance, on the other hand they are expensive. Currently, many researches are mainly focused on new fillers of flexible conductive composites. In this parper, the carbon fiber/Ni and carbon fiber/Co-Ni composite particles were prepared by electroless plating route. The influence of major parameters on the composite particles was studied. The flexible conductive composite were prepared using the composite particles as filler and silicone rubber as matrix material, the conductivity and mechanical properties of flexible conductive composite were studied, in addition, their conductivity were studied when they were stretched and folded. The main work and conclusions are as follows:(1) Using the single variable method, the influences of sodium hypophosphite dosage, aqueous amnion dosage, time and temperature on the conductivity and morphology of the carbon fiber/Ni composite particles were studied. The optimum bath composition and conditions are as follows: Ni SO4 30g/L, Na H2PO2 30g/L, NH3?H2O 120 m L/L, Na3C6H5O7 25g/L, time 30 min and temperature 60℃. Carbon fiber/Ni composite particles were prepared by electroless, the coating on surface of carbon fiber is uniform and compact, the conductivity is good.The volume resistivity of carbon fiber/Ni composite particles is 1.14?10-3??cm.(2) Using the single variable method, the influences of sodium hypophosphite dosage, aqueous amnion dosage, time and temperature on the conductivity and morphology of the carbon fiber/Co-Ni composite particles were studied.The optimum bath composition and conditions are as follows: Ni SO4 15g/L, Co SO4 15g/L, Na H2PO2 30g/L, NH3?H2O 140 m L/L, Na3C6H5O7 30g/L, time 30 min and temperature 80℃. The volume resistivity of carbon fiber/Ni composite particles is 3.27?10-2??cm.(3) The flexible conductive composites were prepared using self-made carbon fiber/Ni composite particles as fillers. The influences of fillers dosage on the conductivity and mechanical properties of composites were studied. When the addition level of carbon fiber/Ni was 30 wt%, the composites had the conductivity of 16.37 S/cm, the tensile strength of 1.68 MPa, the elongation at break of 57.46 %. The conductivity of the composites were studied after they were stretched and folded. The results showed that: the composite could maintain good electrical properties after 0~100 folding cycles and 0~180? folding. When the addition level of carbon fiber/Ni was 30 wt%, the conductivity of the composites is 14.79 S/cm with 30% tensile strain, was reduced 9.7%, The composites conductivity s 11.36 S/cm after 100 stretching cycles, was reduced 30.5%.(4) The flexible conductive composites were prepared using self-made carbon fiber/Co-Ni composite particles as fillers. The influences of fillers dosage on the conductivity and mechanical properties of composites were studied. When the addition level of carbon fiber/Co-Ni was 30 wt%, the composites had the conductivity of 5.39 S/cm, the tensile strength of 1.23 MPa, the elongation at break of 122.62 %. The conductivity of the composites was studied after they were stretched and folded. The results showed that: the composite could maintain good electrical properties when they were folded. When the addition level of carbon fiber/Co-Ni was 30 wt%, the conductivity of the composites with 30% tensile strain reduced 20.4%, The composites conductivity s 1.82 S/cm after 100 stretching cycles, was reduced 66.2 %. |
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