The electrical conductivity of conductive polymer composites(CPCs)with a classical double percolated structure is highly connected to the phase morphology.However,lots of conductive fillers,which are added to guarante...The electrical conductivity of conductive polymer composites(CPCs)with a classical double percolated structure is highly connected to the phase morphology.However,lots of conductive fillers,which are added to guarantee CPCs’electrical conductivity,caused increased viscosity and limited phase coarsening in traditional atmosphere annealing.Herein,a novel processing method of supercritical carbon dioxide(scCO_(2)),assisted phase coarsening for polylactide acid(PLA)/polystyrene(PS)/multi-wall carbon nanotube(MWCNT)composites was explored.It was first proved that obviously coarsened conductive network of double percolation after scCO_(2) annealing was achieved,which benefited from CO_(2) plasticized polymer chains and thus decreased viscosity.Therefore,the electrical properties and electromagnetic interference(EMI)shielding performance of the composites were significantly improved.The percolation threshold of PLA/PS/MWCNT composites decreased from 0.31 wt.%to 0.16 wt.%,and EMI shielding effectiveness increased from 32.8 to 37.4 dB at 5 wt.%MWCNT loading.This work provides a simple,green,and effective way of post-processing to tailor the phase structure via varying conditions of annealing medium such as temperature,CO_(2) pressure,and time,and gains CPCs with improved electrical conductivity and EMI shielding performance.展开更多
基金The authors acknowledge the financial support of the National Natural Science Foundation of China(No.52173039).
文摘The electrical conductivity of conductive polymer composites(CPCs)with a classical double percolated structure is highly connected to the phase morphology.However,lots of conductive fillers,which are added to guarantee CPCs’electrical conductivity,caused increased viscosity and limited phase coarsening in traditional atmosphere annealing.Herein,a novel processing method of supercritical carbon dioxide(scCO_(2)),assisted phase coarsening for polylactide acid(PLA)/polystyrene(PS)/multi-wall carbon nanotube(MWCNT)composites was explored.It was first proved that obviously coarsened conductive network of double percolation after scCO_(2) annealing was achieved,which benefited from CO_(2) plasticized polymer chains and thus decreased viscosity.Therefore,the electrical properties and electromagnetic interference(EMI)shielding performance of the composites were significantly improved.The percolation threshold of PLA/PS/MWCNT composites decreased from 0.31 wt.%to 0.16 wt.%,and EMI shielding effectiveness increased from 32.8 to 37.4 dB at 5 wt.%MWCNT loading.This work provides a simple,green,and effective way of post-processing to tailor the phase structure via varying conditions of annealing medium such as temperature,CO_(2) pressure,and time,and gains CPCs with improved electrical conductivity and EMI shielding performance.
