Effect of compatibilizer on the crystallization kinetics and mechanical properties of nylon 6/LDPE blends

Abstract

The crystallization kinetics of Nylon 6 (PA) in PA/low-density polyethylene (LDPE) blends were studied by differential scanning calorimeter (DSC). The effects of crystallization temperature, blend ratio, and compatibilizer (MOD) on the crystallization kinetics were evaluated by the modified Avrami equation, and the effect of compatibilizer on the mechanical properties of PA/LDPE blends were also investigated. (1) In PA/LDPE blends, the crystallization rate increased with decreasing crystallization temperature in the crystallization temperature range between 181°C and 190°C. (2) In PA/LDPE blends, the introduction of LDPE into PA resulted in an increase in the crystallization rate, while in PA/LDPE/MOD blends the introduction of MOD into the PA/LDPE blend resulted in a decrease in the crystallization rate, which resulted from the partial intermixing of LDPE and MOD in the blends. (3) In PA/LDPE blends, the Avrami exponents were found to be in the neighborhood of three of four over the crystallization temperature range between 181°C and 190°C, almost independent of the composition, while in PA/LDPE/MOD blends, the Avrami exponents showed lower values. In the light of these results and morphological features, it is suggested that for PA/LDPE blends, the crystallization proceeds by athermal nucleation followed by a three dimensional growth, while for PA/LDPE/MOD blends there is a transition from spherulitic growth to somewhat fibrillar growth. (4) PA/LDPE/MOD(80/20/20) blends show a five times higher impact property, with a good balance of tensile properties, than the PA homopolymer.