Structure and properties of PA 6/LDPE/Ionomer ternary blends and PA 6/ionomer binary blends

Abstract

Ternary blends of PA 6/LDPE/Surlyn 9020 inonomer were prepared by melt mixing in a twin-screw extruder. Dynamic mechanical properties and thermal behavior of these blends were studied. The addition of Surlyn 9020 inonomer as a compatibilizer improved the mechanical properties of the blends. The clearest evidence of this improvement was seen in the dynamic mechanical properties. The drop-off modules (corresponding to the solic-liquid trasition) occurred at higher temperatures when compatibililizer was added. Binary blends of PA 6/Surlyn 9650 ionomer over a range of compositions were analyzed for morphology, thermal behavior, X-ray diffraction, rheological behavior, dynamic mechanical properties, impact properties, and interactions of the blends Evidence from a series of glass transition temperatures, together with a positive deviation from the additivity rule for the complex viscosity/composition relationship, clearly indicated that PA 6/ionomer blends had limited miscibility, However, chemical reactions occurred between the two components, thus enhancing the miscibility of the blends. DSC and X-ray diffraction results showed complete absence of any co-crystallization or interactions between the crystalline phases of the blend components. Fracture surfaces of PA 6/ionomer blends showed indistinct dispersed phase morphologics. A significant improvement in impact strength was observed for PA 6/ionomer blends compared with pure PA6.