Reactive blending of polyamide 6, 6 and vectra A, -Role of a bifunctional epoxy coupler

In a previous paper Nylon 6,6 / Vectra A blends have been prepared and investigated; in particular our attention has been focused on Nylon 6,6 modifications due to interchange reactions that occur in the melt, as a function of mixing conditions and blend compositions, and improve the compatibility of the blend. The results indicated that only a small amount of copolymeric species form because of the low reaction kinetics and unfavourable physical and rheological aspects. In order to overcome these limits a further research on Nylon 6,6 / Vectra A blends has been carried out to test the role of modified processing conditions in the presence of a reactive additive able to improve the extent of reactions between blend components and the melt viscosity of the polyamide matrix. The potential of a Nylon 6,6 sample with predominant -NH2 end groups on its reactive blending with Vectra with or without the reactive third component has been investigated. Nylon and Vectra, combined in weight ratios between 90/10 and 50/50, were subjected to reactive blending with different methods (a laboratory pyrex reactor, a single-screw extruder and a Brabender mixer). Neat Nylon samples have been also investigated as reference materials. Thermal and morphological analyses were carried out on the blends. The soluble Nylon 6,6-rich fraction of each blend was separated from the insoluble Vectra-rich one and both used for spectroscopic characterisations; mixed Nylon-Vectra copolymers have been recognised in both the soluble and insoluble fractions of the blends.