Conductive Properties Of ABS/Stainless Steel Fiber Composites

Stainless steel fiber conductive composite materials are made of stainless steel fibers as main conductive fillers, graphite as the auxiliary and thermoplastic polymer as matrix, and then be prepared and moulded after the mixer mixing into thermoplastic polymer. They have excellent electric conductivity and high plasticity like polymer material, can satisfy the use requirement of electromagnetic shielding materials and conductive composites.In this paper, the condutive composites were preparated by stainless steel fibers(SSF) and graphite as conductive fillers, acrylonitrile/butadiene/styrene copolymer(ABS) and polyvinylidene fluoride(PVDF) as matrix. Respectively studied the surface modification of stainless steel fibers; the association of conductive percolation behavior and rheological characteristic of conductive composites, resistance-temperature properties and conductive mechanism under DMA multifrequency strain mode- micro-dynamic force field; how to toughen the matrix of ABS/PVDF/SSF/graphite quaternary system and conductive mechanism and correlation of the rheological percolation behavior and percolation behavior. The results showed:(1)The stainless steel interface bonding between the fiber and matrix resin was improved obviously by the silane coupling agent WD – 50. The mechanical properties of the composite system was best, volume resistivity was the lowest and viscoelasticity was best when the dosage of WD – 50 was 1.5%.(2)Adding the second phase of graphite conductive fillers of 10 wt% could reduce the percolation threshold of complex system from 18%~19% to 14%~15%. In ABS/SSF/graphite composite system, with the increase of stainless steel fibers, the seepage phenomenon of the complex system was appeared in low frequency region, and the rheological percolation threshold was close to the conductive percolation threshold; and under the constant frequency, the resistance positive temperature effect(PTC) and negative temperature resistance effect(NTC) were appeared in the complex system with the increase of temperature, the temperature of PTC transition peak’s occurrence was lower with the increase of SSF content; in addition, with the increase of ω, the volume resistivity variation was increased and the dynamic storage modulus G’ was declined in the same component of complex system(3)Using PVDF on toughening modification of ABS, found that when ABS:PVDF =20:80, the viscosity of compound system was lower, the change of relative shear rate was stability, the mechanical and electrical properties were better. With the increasing of stainless steel fibers, the viscoelastic permeability effection was appeared in ABS/PVDF/stainless steel fiber/graphite composite system. That was when the stainless steel fibers’ content was between 15%~20% and 25%~30%, the compound viscosity, dynamic modulus and volume resistivity curves of ABS/PVDF/SSF/graphite quaternary system were all appeared “double permeability” phenomenon. Compared with the ABS/SSF/graphite ternary system, the total dosage of conductive fillers and volume resistivity of complex system were greatly reduced.