Morphology, viscoelastic properties and the mechanical performance of highly toughened polyamide 6/acrylonitrile–butadiene–styrene/polylactic acid ternary blends

Abstract

In this research, the morphology, rheology, and mechanical performance of polyamide 6/polylactic acid/acrylonitrile–butadiene–styrene (PA6/ABS/PLA) ternary blends were studied. The optimum ABS percentage in PA6/ABS binary blend to achieve highly toughened blend was determined around 35 wt.%. The spreading coefficient (Sij) predictions showed that each of PLA and ABS can form separate phase in the PA6 matrix. The evaluation of the interfacial interactions in the ternary blends revealed a higher tendency of PLA to interact with PA6 chains (Sij:−1.20) rather than ABS (Sij:−0.20) which is in comply with higher work of adhesion of PLA/PA6 than PLA/ABS and PA6/ABS. By adding PLA to the binary blends of PA6/ABS, it was found that the ABS domain size decreased due to rheological change. The localization of each component in the ternary blends observed in SEM analysis was in agreement with spreading coefficient predictions. Morphological evaluations revealed higher interfacial interactions between PA6 and PLA in the blends with up to 20 wt.% PLA. The optimized blend ratio of ternary blends showed higher complex viscosity at low shear rates and higher values than the mixing rule prediction. The optimum flexural modulus of 2 GPa and impact resistance of 47 kJ/m2 were achieved at 20 wt.% PLA in PA6/ABS/PLA ternary blend. The optimum PA6/ABS blend ratio to achieve high toughness was determined. The phase localization in the blends predicted via Spreading Coefficient. The interaction of PA6 and ABS enhanced by the addition of PLA in the blends. The mechanical properties of blends are correlated with rheological behavior. The flexural modulus of blends was higher than Halpin–Tsai model predictions.