| Polymer films such as ethylene-vinyl acetate copolymer(EVA),thermoplastic polyurethane(TPU)and engineering materials polypropylenehave(PP)potentially broad application in complex field due to their excellent processability,low cost and superior mechanical properties,but their thermal conductivity and antistatic properties are deficient.New carbon materials such as graphene nanoribbons(GNRs)and graphene,with excellent thermal and electrical conductivity and comprehensive performance,If the GNRs or graphene are uniformly dispersed in the polymer matrix,the thermal conductivity and other properties of the composite material can be greatly improved.However,GNRs and graphene are easy to agglomerate and are not easily dispersed in most organic solvents.This feature is not conducive to their in-depth research and development.For this reason,the doping design was used to load the conductive polymer on the surface of nanofiller,and the thermoplastic composites based on different morphologies were prepared.The thermal conductivity and electrical conductivity of the composites were studied in detail.The relevant researches and conclusions are listed as follows:Oxidation and cleavage of MWCNTs by using Hummers method to prepare graphene oxide nanoribbons(GONRs),in situ polymerization of poly-p-phenylenediamine on its surface,and then reduced by hydrazine hydrate to give RGONRs-PPDA nanocomposites.The effects of RGONRs-PPDA content on the barrier,thermal conductivity and antistatic properties of EVA composite films were investigated.The research shows:The RGONRs-PPDA dopant can effectively improve the dispersibility of the filler in organic solvent,which can help to achieve a uniform and stable distribution in the polymer matrix.Both of them play a synergistic effect and can greatly improve the antistatic properties and thermal conductivity of the EVA composite film.The permeability of the RGONRs-PPDA/EVA composite film was about 0.6-0.8 wt%,Comparing with the pure EVA,the OTR of RGONRs-PPDA/EVA composite films is reduced by 68.49%,the thermal conductivity exceeds 1.2W/(m K)when the mass fraction of RGONRs-PPDA is 0.8%.Graphene oxide(GO)was obtained by Hummers method,and poly(p-phenylenediamine)was polymerized in situ on its surface,After being reduced by hydrazine hydrate,RGO-PPDA nanocomplexes are obtained at last.The effects of different content of GO-PPDA and RGO-PPDA on the thermal conductivity and barrier properties of TPU composite films were compared.The study found that the lipophilicity of the complex of RGONRs-PPDA obtained after the reduction of hydrazine was significantly improved,the dispersion in DMF well,dispersed in the TPU matrix uniform and stable distribution.Comparing with the pure TPU,the OTR of RGONRs-PPDA composite films is reduced by 73,28%,the pv decreased by 8 orders of magnitude and the thermal conductivity exceeds 1W/(m·K)when the mass fraction of RGONRs-PPDA is 0.8%.With low cost,rich source of cost-effective halloysite nanotubes instead of high performance but costly carbon filler,The conductive polymer polyaniline was loaded on the surface of halloysite nanotubes to prepare a halloysite nanotube doped polyaniline HNTs-PANI composite.The effects of HNTs-PANI on the anti-static,thermal conductivity,flame retardancy and mechanical properties of PP composites were investigated.The results show that Comparing with the neat PP,the p,decreased by 7 orders,the thermal conductivity increased 2.906 times when the mass fraction of HNTs-PANI is5%.At the same time,the addition of HNTs-PANI also helps improve the flame retardant and mechanical properties of PP composites. |
