Study On The Blending And Properties Of PTT/PA-6

PA-6 has been widely used as plastics because of its fine mechanical properties, wear resistance and corrosion resistance, but it also has poor mechanical stability and creep resistance due to its good hydroscopicity. PA-6 is also used as fiber because of its soft handle, good recovery and wear resistance, however, it has poor anti-pollution and antistatic properties. AS a kind of novel polyester, PTT plastics has excellent mechanical properties and low water absorption, and PTT fiber takes an unusual combination of properties of most chemical fibers in common use. In the present contribution, the system of PTT/PA-6 was researched. Beacause the report about PTT/PA-6 system is rarely, so it is significant and valuable to study on the system of PTT/PA-6 blends.Study on the effects of blending technics to PTT/PA-6 blends showed that, the compatibility of the system was a little influenced by prolonging blending time, but could be evidently improved by increasing blending temperature.The molecular simulation software Materials studio4.0 was used to calculate the solubility parameter and mixture free energy of PTT and PA-6, the results indicated that PTT/PA-6 was an incompatible system. The experimental results obtained from DSC, SEM and WAXD data showed that PTT/PA-6 was incompatible in both amorphous and crystal regions. When PTT was the dispersed phase, there existed fractional crystallization, and the compatibility of the system was relatively better. DSC results indicated that the crystallization capacity and crystallization rate of the blends got higher than the pure components, while the crystallinity got smaller.DSC、SEM and rheological results showed that 4% of compatibilizer PE-g-MAH was added, the compatibility of the system got the best, the shear stress and apparent viscosity of the melts got the largest, and the viscous flow activation energy was relatively lower, which was beneficial to control the processing technology.Study on the hydroscopicity of PTT/PA-6 blends also illustrated the addition of PTT component could evidently decrease the water absorption of PA-6, and the addition of PE-g-MAH could decrease the water absorption furthermore. However, when PE-g-MAH content got 10%, the water absorption got higher instead.It was also found from the study on the mechanical properties of PE-g-MAH compatibilized blends, when PTT content was 0%-30%, the tensile strength decreased a little and notched impact strength decreased a lot, when PTT content was larger than 50%, the tensile strength also decreased greatly. Although blending PTT and PA-6 caused the decreasing of mechanical properties, it could also be found by comparing the mechanical data of wet and dry samples that when PTT content was 30%, the tensile strength of wet samples was the highest. When PTT content was 0%-30%, the notched impact strength of wet samples were a little higher than that of the dry ones. Otherwise, when 4% of PE-g-MAH was added, the mechanical properties for both dry and wet samples got the best.By spinning the blends, it was found that PTT/PA-6/PE-g-MAH was 30/70/4, the blend sample can be spinning by using spinning speed 300m/min. Nevertheless, it needs further improvement by controling spinning process and choosing a better compatibilizer or some way else.