Manipulation of the properties of PLA nanocomposites by controlling the distribution of nanoclay via varying the acrylonitrile content in NBR rubber

Nanocomposites based on blends of polylactide (PLA), acrylonitrile butadiene rubber (NBR) and 4 wt% organically modified nanoclay (Cloisite 10A) were prepared via melt compounding. To investigate the influence of NBR acrylonitrile (ACN) content on the dispersion state and localization of nanoclay and micromorphology of the blends, three different NBRs with low (19%), medium (33%) and high (51%) ACN content were employed. Nanocomposites with low ACN NBR exhibited higher dispersion of clay nanolayers within the PLA matrix, whereas increase in ACN content gave rise to the localization of silicate platelets within the interface of two phases which was consistent well with the enhanced interfacial interaction between PLA and NBR phases that was evidenced by surface tension and melt rheology analysis. The size of dispersed NBR droplets decreased by the incorporation of organoclay into the composition of all PLA/NBR blends irrespective of the ACN content. However, the reduction in NBR droplet size by the nanoclay layers showed to be more pronounced for the nanocomposites based on high ACN rubber phase as a result of higher localization of nanoclay platelets within the interface of the PLA and NBR. All nanocomposites exhibited significant increase in elongation at break than simple blend counterparts, implying intensification of PLA and NBR interface by nanoclay incorporation.