Dynamically vulcanized polylactide/nitrile butadiene rubber blends with continuous cross-linked rubber phase

Thermoplastic vulcanizates (TPVs) based on polylactide (PLA)/nitrile butadiene rubber (NBR) blends were prepared by dynamic vulcanization and the PLA matrix was plasticized by dioctyl phthalate (DOP). The surface morphologies of the etched PLA/DOP/NBR TPVs were studied by field emission scanning electron microscope, and the element contents in the TPV surface were characterized by energy dispersive X-Ray spectroscopy; moreover, the dissolution/swell behaviors, infrared spectra and rheological behavior of the prepared PLA/DOP/NBR TPV were also characterized. Experimental results indicated that the cross-linked NBR in the PLA/DOP/NBR TPVs owned a continuous network-like structure due to the much difference in the viscosity between the NBR rubber and the PLA resin. This unique finding breaks the traditional concept of a sea-island morphology which was formed after dynamic vulcanization of the thermoplastic resin/rubber blends. PLA grafted onto NBR under the action of DCP vulcanizing agent, leading to the improving interface compatibility. It should be noted that this PLA/DOP/NBR TPV with the novel microstructure has never been reported.