Study On The Extrusion Extrusion Of Caprolactam Anionic Polymerized Nylon 6/polystyrene In-situ Alloy

A novel method has been developed for the synthesis of PA6/PS blends via continuously in-situ free radical polymerization and anionic ring-opening polymerization by reactive extrusion.SEM, DSC, TG and electronic universal testing machine were used to investigate the morphological structure, crystallization property, thermal properties, mechanical property, and so on. At the same time, the relationship between the PS content and various properties of PA6/PS blends was investigated.First of all, molten mixture of PS and CL was used to prepare PA6/PS in situ blend via anionic ring-opening polymerization of CL by reactive extrusion. The cross section of PA6/PS in situ blends etched by tetrahydrofuran was observed by SEM. An especial phase inversion occured with the change o PS content, which showed that the structure of the blends transferred from PS dispersed/PA6 matrix to PA6 dispersed/PS matrix when the PS content was higher than30 wt.%. Phase inversion with such low component content could seldom be found in traditional polymer blends. Besides, the mechanism of phase inversion based on polymerization induced phase separation was also discussed.Secondly, the PA6/PS in situ blends containing fibrillar or microspherical PA6 phase in PS matrix structure were prepared by anionic polymerization via reactive extrusion based on polymerization induced phase separation in this study. Fibrillar or microspherical PA6 were obtained after removing PS continuous phase of PA6/PS blends when the PS content were30~45wt% and 50wt%, respectively, The relationships between PS content and the structure of PA6 microfibers and microspheres were studied also.At last, the properties of PA6/PS in situ blends prepared by anionic polymerization via reactive extrusion were characterized. DSC analysis showed that the thermal stability of PA6/PS blends prepared in same extrusion conditions was unaffected by PS content. The melting temperature of PA6/PS blends were the same as pure PA6 though PS content was different. The initial decomposition temperature of the blends increased at first and then decreased with the increase of PS content. However, PS content had no effect on the termination decomposition. On the other hand, the decomposition temperature of the blends decreased before 100? with increasing PS content because the water absorbent of PA6 can be reduced by PS. In addition,mechanical properties of PA6/PS in situ blends via reactive extrusion showed that the tensile strength, elongation at break and flexural strength were all decreased and flexural modulus, and notched impact strength were increased with increasing PS content.