Compatibilization and morphology improvement of PA66/HDPE blends by addition of modified EVOH and nanoclay

To produce a compatibilizer for PA66/HDPE blend, chemical modification of EVOH (ethylene content 44 mol %) was carried out in a five step procedure, in which nylon segments were grafted onto EVOH copolymer through hydroxyl groups on the EVOH chains. The presence of the grafted nylon was investigated by FTIR analysis. Consequently, PA66/HDPE blends were prepared in a Brabender mixer, with polyamide as the major constituent. Scanning electron microscopy (SEM) indicates that, as a compatibilizer, modified EVOH (designated as EVOH-g-PA) shows effective compatibilization in the PA66/HDPE blends. The differential scanning calorimetry (DSC) results confirm that the EVOH-g-PA causes a decrease in the crystallization temperature of PA66 phase and, therefore, reduction in crystallinity of PA66. A reduction of the average size of the polyethylene droplets was observed upon addition of either pristine or modified clay, in which the modified clay has been prepared via interfacial polycondensation (IPC) process of PA66.

Keywords:

Polymer blends , Compatibilization , EVOH , Modification , Nanoclay