Evaluation of the rheological and electrical percolation of high‐density polyethylene/carbon black composites using mathematical models

Abstract

In this work, conductive polymer composites (CPCs) of bio‐based polyethylene (BioPe) containing different concentrations of carbon black (CB) were developed. By using oscillatory rheology analysis, a Newtonian plateau was observed in BioPe, and all BioPe/CB composites had a behavior of a pseudo‐solid and that composites with volume fractions ranging from 0.24 to 0.56 presented higher viscosity, storage, and loss modulus. This suggests the formation of a percolated network and by using the power‐law models, it was observed that the electrical percolation threshold was higher than the rheological percolation threshold. The electrical conductivity was measured using the four‐point probe method and a sigmoid model was used to predict the CPCs' electrical conductivity percolation threshold. The results indicated that the four‐point probe method presented satisfactory results according to the calculated standard deviations and voltage–current characteristics for each round of measurements considering the same ranging as used in rheology analysis. The analytical model used showed a coefficient of determination (R2) higher than 95%, allowing the prediction of the electrical conductivity of the CPC and the percolation threshold as a function of the volumetric fraction of the CB.

Enhanced thermal conductivity of polycarbonate‐based composites by constructing a dense filler packing structure consisting of hybrid boron nitride and flake graphite

“…The decrease in the values of tan δ with increasing filler content coupling with the simultaneous shift of maximum tan δ to higher frequency regions suggested the transition of polymer melts from the viscous‐like state to solid‐like state, which is related to the structural change that induced by the formation of filler network 64,65 . Particularly, Figure 6c showed that the values of tan δ were almost independent of frequency for CBG, which indicated the construction of a well‐developed percolated filler network structure 66 …”

Linear and Nonlinear Viscoelasticity of Polypropylene Containing Cross‐Linked Gels

“…The critical volume fraction for achieving the percolation threshold is low for nanoparticles, which has been reported previously. [ 58,59 ] With a micrometer size particle‐like in the present PP gel systems, the critical percolation threshold volume reaches a plateau, and then increases slowly with particle size. At 16 wt% gel incorporation, assuming the constrained corona thickness is the same as in G2.5, G5, and G11, the effective volume fraction of G16 is equal to 51 vol%, which is close to the obtained percolation volume fraction.…”

Tailoring Nylon 6/Acrylonitrile-Butadiene-Styrene Nanocomposites for Application against Electromagnetic Interference: Evaluation of the Mechanical, Thermal and Electrical Behavior, and the Electromagnetic Shielding Efficiency

“…This behavior indicates an increment in the viscoelastic characteristics of the nanocomposites caused by MWCNT. The Nylon 6/ABS/ABS-g-MA/MWCNT systems presented increased G’ values with increasing nanofiller content, mainly in the low-frequency region, which is typical of polymers loaded with conductive particles [ 55 , 56 ]. The nanocomposites containing 3 and 5 phr MWCNT presented higher G’ values than the sample with 1 phr MWCNT, following the same behavior observed for η*.…”