.pa6/1212, Pa66/1212, Pa6/66/1212 Binary, Ternary Copolymer Research

In this paper, PA6/1212, PA66/1212, PA6/66/1212 copolymers were synthesized by melt polycondensation based on caprolactam, nylon 66 salt, nylon 1212 salt. The PA6/1212, PA66/1212 copolymers were characterized and the ternary diagram of PA6/66/1212 copolymers were determined by melting point analysis.The apparent phase diagrams of PA6/1212, PA66/1212 copolymers were determined by melting point analysis. The minimum points of PA6/1212 and PA66/1212 copolymers are 130.5 and 140℃ when the weight ratio of caprolactam and nylon 1212 salt is 40:60 and nylon 66 salt and nylon 1212 salt is 30: 70 respectively. The relative viscosity (η_r ), density and water absorptivity weremeasured. The results indicated that the practical value of density is close to the theoretical value of density. The water absorptivity decreases quickly when the content of PA1212 is less than 30% .The morphology of PA6/1212 crystallization under 10°C of melting point was observed by PLM. Positive, mixable optical, negative and negative spherulite with the helical ring of PA6/1212 were found. The melting behaviors of the first and second melting state and crystalline behaviors of PA6/1212 copolymers were studied by DSC. In the first melting DSC curves, the binary endothermic peaks were observed in the PA6/1212 copolymers, and the sizes of the endothermic peaks are the smallest when the content of PA1212 is 40-50%. When the content of PA1212 is 50-80%, the crystal peak is unobvious, but the cold crystallization was found in the second melting state. The crystalline transition behavior of PA6/1212 copolymers was studied byWAXD and IR and the results were identical. They form crystal of PA6/1212 copolymers could be transformed from the α, γ form crystal coexistent when thecontent of PA1212 is 50%. TG results indicated that the thermal degradation process of PA6/1212 is one-step reaction under N₂. T₀, T_f , T_p of PA6/1212 copolymers arehigher than that of PA6, PA1212.The effects of PA1212 content on the mechanical properties of PA6/1212...