The Effect Of Filler Functionalization On The Conductive Networks Formation Of Elastomer Composites By Molecular Dynamics Simulation

Improving the conductivity of elastomer-based nanocomposites can expand the application range of composites.The functionalization of conductive fillers(nanoparticle and nanorod)is a great method that can effectively improve its compatibility with the elastomer matrix,which will facilitate the formation of conductive networks in nanocomposite systems.In this project,by adopting coarse-grained molecular dynamics simulation,we established the systems with functionalized nanoparticles(NPs)and functionalized nanorods(NRs)respectively.The effect of filler functionalization degree on the conductive networks formation under static and dynamic shear was mainly studied.The specific work is as follows:(1)The effect of nanoparticle(NP)functionalization on the formation of nanocomposite conductive networkThe systems with different nanoparticle(NP)functionalization degree a were established to characterize the dispersion state of NPs,the conductive probability and the formation of conductive networks.It can be found that NPs varies from the contact aggregation,the relatively uniform dispersion to the local bridging structure via one polymer layer with the increase of ?.Corresponding to it,the percolation threshold cpc decreases,and the main cluster size Cn of the conductive network increases.All of those indicate that the local bridging structure of NPs can form a continuous and effective conductive network.In addition,even though the dispersion state of NPs is different for ??0.2,the conductive probability is similar under the shear field.This manifests that the conductive network is not completely related to the dispersion state of the filler,it also affected by the connection mode among NPs.(2)The effect of nanorod(NR)functionalization on the formation of nanocomposite conductive networkThe nanorod functionalization degree ? and ?PA(the interaction between polymer and A beads)were turned to investigate the system with great electrical conductivity.It is found that the direct aggregation and local orientation structure of NRs are broken down with the increasing of ?,which improves their dispersion state.And there is an anti N-type between cpc and ?.As the ?pA increases,?c first decreases and then increases,so when ?=0.1 and ?pA=3.0,the system has the excellent conductive performance.In addition,there is a significant change in the percolation threshold after the shear,which is attributed to the high orientation and the change of NRs dispersion state under the shear field.Especially,the dispersion state of NRs is different,but ?c is similar and nearly independent on the ?.That is to say,the conductive network is not completely related to the dispersion state of NRs.