New ternary PLA/organoclay-hydrogel nanocomposites: Design, preparation and study on thermal, combustion and mechanical properties

Abstract

A new ternary nanocomposite system containing polylactic acid, an organoclay and a hydrogel was designed and prepared by solution casting method. The hydrogel was synthesized from 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and N,N′-methylenebisacrylamide (MBA) via a radical polymerization in the presence of ammonium persulfate (APS). As a potential reinforcement, the hydrogel was used in a PLA system combined with and without a new organoclay. The organoclay was prepared from Cloisite Na+ and protonated form of SABO®STAB UV 94 via an ion-exchange reaction. The morphology, mechanical, thermal and combustion properties of all the PLA systems were studied. In the presence of the organoclay, the hydrogel showed a synergistic effect on improving all the investigated properties of PLA. The temperature at 5mass% loss (T5) was increased from 308°C to 325°C in PLA/hydrogel-organoclay nanocomposite containing 3mass% of each the hydrogel and organoclay (PSH 6) as compared to the neat PLA. The peak heat release rate was decreased from 567.3W/g for PLA to 410.1W/g for PSH 6. According to the mechanical tests results, as compared with the neat PLA, by adding both of the hydrogel and organoclay into PLA matrix, the tensile strength was increased from 43.7 to 64.4MPa.