Control of morphology and mechanical properties in polyamide-based blends through reactive compatibilization

Imidized acrylic polymers were tested as compatibilizers for polyamide blends prepared in a single screw extruder with styrene/acrylonitrile (SAN) copolymers. Transmission electron microscopy (TEM) techniques were used to examine the morphology of this model system and correlate the functionality and miscibility characteristics of the imidized acrylic polymers with the morphology of the dispersed phase in these blends. Based on the model study an optimal imidized acrylic compatibilizer was selected for extensively investigating the mechanical properties and morphology of the more complex, but commercially important nylon/ABS blends. For both nylon/SAN and nylon/ABS systems imidized acrylic polymers which were miscible with the SAN phase and had sufficient total acid functionality (anhydride plus free acid) proved to be most effective. The effects of varying the physical and chemical characteristics of the polyamide materials in these blends were also investigated.; The morphology and mechanical properties of blends of a series of polyamide materials with a maleated triblock copolymer (which had an ethylene/butylene midblock and styrene end blocks, or SEBS-g-MA) were also investigated. The monofunctional (nylon x) polyamides led to small, regular particles; while, the difunctional (nylon x,y) polyamides led to rubber particles much more complex in shape which decreased in size as the aliphatic content of the nylon was increased. The effects of more intense mixing using a twin screw extruder in compatibilized polyamide blends with ABS, SEBS-g-MA and an ethylene-propylene rubber (EPR-g-MA) were also investigated. Deformation mechanisms in compatibilized nylon 6 blends with ABS and SEBS-g-MA were investigated using TEM techniques.