Preparation And Characterization Of In Situ Compatibilized PA6/POE Blends

Polyamide 6 (nylon 6) is one of the most used thermoplastic due to its easy processing, wear resistance, and high melting temperature. The broader application of PA 6, however, is limited by its brittleness and high water absorption.In order to improve its toughness, PA6/POE composites were prepared by in-situ compatibilization technology in the present of L101 and MAH, and the mechanical properties, morphology structure, rheological behavior and crystallization properties were investigated by tensile/impact strength testing, scanning electron microscopy (SEM), capillary rheometer, differential scanning calorimeter (DSC) and polarizing microscopy (POM).The experimental results demonstrated that the toughness of PA 6 were improved significantly by in-situ compatibilization technology. When the composition PA 6/POE/L101/MAH was 70/30/0.12/1, it gave 65.2KJ/m2 of impact strength, which was increased by 14.5 times as compared to that of neat PA6 (4.5KJ/m2). SEM analysis showed that the POE dispersed uniformly in PA6 matrix in the form of smaller dimension, which played a key role in the improvement of the toughness.The rheological behavior of PA6/POE composites with various L101 content was investigated. The results showed that PA6/POE composites were pseudo-plasitc. In the case of constant shear stress and shear rate, the apparent viscosity increased with the increase of the L101 concentration, and gave the maximum value in the case of 0.12 % L101 loading. The apparent viscous activation energy of the blends tended to decrease with the increasing L101 concentration, it was indicated that the blend displayed slight processing temperature-sensitivity.The crystallization kinetics of PA6/POE blends with various L101 concentration was investigated by DSC. As demonstrated by the analysis of the isothermal crystallization kinetics, Avrami equation can describe isothermal crystallization of PA6 and its blends very well. The interaction between PA 6 and POE was improved by the in-situ formation of POE-g-MAH during the extrusion process. Such strong interaction restricted the chain mobility of PA 6 and correspondingly hindered the crystallization rate of PA 6. However, the mechanism of nucleation and growth of PA6/POE composites was not changed by the addition of L101. The equilibrium melting temperatures of PA 6/POE blends determined by the Hoffman-Weeks theory were lower than that of the neat PA 6, which indicated that the in-situ compatibilization technology decreased the perfection of crystals.The analysis of non-isothermal crystallization showed that the modified Avrami and Mo equation take great advantages over treating the non-isothermal crystallization kinetics. The in-situ compatibilization impeded the growth of crystals and the crystallization rate while it didn't change the nucleation and growth model of PA 6 crystals.