Influences of carbon nanotube on structures and properties of compatibilized polylactide/polypropylene blend-based ternary nanocomposites

Abstract

To attain eco-friendly and multifunctional thermoplastic composites for advanced applications, a series of ternary nanocomposites based on compatibilized polylactide/glycidyl methacrylate-grafted polypropylene (PLA/PGMA, 80/20 by wt%) blend matrix and 0.5–10 wt% multi-walled carbon nanotube (MWCNT) filler is manufactured by efficient masterbatch melt-compounding. Effects of MWCNT on the morphology, thermal, mechanical, rheological, electrical, and EMI shielding properties of the ternary nanocomposites are investigated. It is revealed that PGMA/MWCNT domains are partially formed owing to the selective interaction of MWCNT with PGMA in the blend matrix. MWCNTs contribute to accelerating the crystallization rates of PGMA and PLA matrix components in the ternary nanocomposites. The dynamic mechanical modulus and thermal stability of the ternary nanocomposites are improved with the increment of MWCNT loading. The electrical conductivity of the nanocomposites increases significantly from ∼10−11 S/cm to ∼10−3 S/cm with increasing the MWCNT content up to 10 wt%. The electrical percolation threshold of ∼4.0 wt% MWCNT is also found to be in good agreement with the rheologically estimated percolation threshold. The EMI shielding effectiveness of 1 mm thick ternary nanocomposite with 10 wt% MWCNT is measured to be ∼13.4 dB at 8 GHz, which indicates the shielding efficiency of ∼95.4% to incident EM waves.