Large-scale preparation of segregated PLA/carbon nanotube composite with high efficient electromagnetic interference shielding and favourable mechanical properties

Abstract

Environment friendly conductive polymer composites (CPCs) with high electromagnetic interference (EMI) shielding performance and favourable mechanical properties were successfully produced on large scale from poly (l-lactid acid) (PLLA), poly (lactic acid) stereocomplex crystallite (PLASC) and multi-wall carbon nanotube (MWCNT). The morphology results indicated that the perfect segregated structure was easily manipulated by controlling the injection temperature. The prepared composite exhibits good conductivity and high EMI shielding effectiveness (EMI SE) under low MWCNT content due to the selective dispersion of the conductive MWCNT in the continuous PLLA phase. With the addition of only 3 wt% MWCNT, the composite exhibits high electrical conductivity of 6.42 S/m and outstanding EMI shielding performance of 31.02 dB at 8.2 GHz. Moreover, similar molecular structure between PLLA and PLAsc endowed excellent interfacial adhesion, thus results in favourable mechanical properties of composites. The work provides a novel idea for manufacting high EMI shielding materials with both toughness and degradation.