Preparation and properties of PLA/long alkyl chain modified multi-walled carbon nanotubes nanocomposites

Abstract

In this investigation, poly(lactic) acid (PLA)/multi-walled carbon nanotubes (CNTs) hybrids were prepared using a melt blending process. To increase the compatibility between CNTs and PLA, the surfaces of the CNTs were fi rstly pretreated in acid solution (HNO 3 ) to functionalize them with carboxylic groups (-COOH). Then, stearyl alcohol was grafted onto carboxylic groups using a dehydrating agent, N,N ′ -dicyclohexylcarbodiimide. Chemically modifi ed CNTs (CNT-C18) were thus obtained. Therefore, modifi ed carbon nanotubes (CNT-C18) dispersed excellently in organic solvents. PLA/CNTs nanocomposites were prepared by the meltblending method. Experimental results reveal that the PLA/ CNT-C18 nanocomposites that consisted of well-dispersed nanotubes exhibited enhanced thermal and mechanical properties. Adding 4 wt % CNT-C18 to a nanocomposite increased the storage modulus ( E ′ ) at 40 ° C by 17.8 % , and the loss modulus ( E ″ ) at the glass transition temperature ( T g ) by 15.1 % . Adding 3 wt % CNT-C18 also reduced the surface resistivity of the PLA nanocomposites from > 10 16 Ω /cm 2 to 10 4 Ω /cm 2 . Such PLA/CNT-C18 nanocomposites are highly effi cient in anti-static agents and can be exploited in the outer coverings of electronic devices.