Facile preparation of in situ special-shaped microfibrillar polyolefin elastomer/poly(lactic acid)/polyamide 6 composites

In situ special-shaped microfibrillar composites, employing polyolefin elastomer (POE) as matrix and poly(lactic acid)/polyamide 6 (PLA/PA6) masterbatch as dispersed phase, were successfully prepared by using multistage stretching extrusion technology. The special-shaped microfibrils liking "gourd skewers" or "trepang" can be readily tuned by changing the weight ratio of PLA to PA6 in the POE/(PLA/PA6) composites. It was found that the morphological evolution of special shaped structure microfibril were mainly ascribed to the phase separation and viscosity difference between PLA and PA6 during stretching extrusion process. Owing to the large specific surface area and the "hang nail" effect of special-shaped microfibrils, the excellent elongation at break(867%) and tensile strength (20.1 MPa) can be achieved for the POE/(PLA/PA6) composites (PLA/PA6 = 12.5/12.5), which were 1.2 and 2 times higher than those of pure POE respectively. Dynamic rheology studies showed that the viscoelasticity of POE/(PLA/PA6) composites can be improved significantly compared to pure POE. This work provided a facile and cost-effective way to fabricate special shaped microfibrillar composites to improved strength and toughness simultaneously.