Reactive blending of poly(ethylene 2,6-naphthalate) and Vectra A

In situ composites based on poly(ethylene 2,6-naphthalate) (PEN) and a thermotropic liquid crystal polymer (Vectra A950) were prepared by melt blending under different processing conditions. Thermal behaviour, mechanical and physical properties and morphology of the blends were investigated. The DSC analysis indicates that, as expected, Vectra enhances the crystallization process of PEN. Moreover, mechanical and thermal tests evidence the significant role of 20 wt% Vectra on increasing the material performances; tensile properties, coupled with SEM, show that strength and modulus of PEN are significantly improved when Vectra domains are long and continuous fibrils. The overall results can be attributed to the compatibilisation of the system induced by the mixing conditions that affect the extent of transreactions occurring in the melt. To deepen this aspect, the soluble and insoluble fractions in a PEN solvent were isolated and thoroughly characterized: both the fractions contain PEN/Vectra copolymers. The results underline the potentiality of the PEN/Vectra system for different high-performance applications requiring superior strength and modulus, heat stability or barrier properties.