Compatibilization effect of MMA-co-GMA copolymers on the properties of polyamide 6/Poly(vinylidene fluoride) blends

Methyl methacrylate-co-glycidyl methacrylate copolymers (MMA-co-GMA) with different GMA contents were prepared to compatibilize the polyamide 6 (PA6) and poly(vinylidene fluoride) (PVDF) blend. The chemical reactions between the carboxyl/amino end groups of PA6 and the epoxy groups, and the good miscibility between PVDF and MMA-co-GMA were responsible for the excellent compatibilization effect. DMA results showed that the glass transition peaks of PVDF phase almost disappeared in the PA6/PVDF/MMA-co-GMA blends; this proved the suppressed thermal transition due to the restricted movement of PVDF chains. MMA-co-GMA copolymers significantly decreased the phase domain size of the PA6/PVDF blends. PVDF dispersed in the PA6 matrix uniformly and the interface between the two phases was obscure due to the compatibilization. The addition of MMA-co-GMA into the PA6/PVDF blend decreased the crystallization temperature of the PVDF phase, which proved that the compatibilizer enhanced the interaction between PVDF and PA6 and retarded the crystallization. Mechanical tests indicated that the impact strength and elongation at break of the PA6/PVDF blends increased with the addition of MMA-co-GMA. The increase of the fracture toughness was due to the compatibilization effect of MMA-co-GMA copolymers, which induced a delay of the debonding of PA6 and PVDF phases at the interface and inhibited the initiation and propagation of cracks.