Blends of low-density polyethylene with nylon compatibilized with sodium-neutralized carboxylate ionomers

Abstract

An ethylene-methacrylic acid copolymer partially neutralized with sodium (Na-EMAA), was successfully applied to compatibilize nylon6 (Ny6) and low-density polyethylene (LDPE) blends. The phase morphology and thermal behavior of these blends were investigated over range of composition, using SEM, TGA, DSC, and WAXS. It was found that the addition of small amount (0.5 phr) of Na-EMAA improved the compatible of the Ny6/LDPE blends; the uniformity and the reduction of dispersed phase size was observed. TGA measurement demonstrated the synergistic effect of the thermal stability when Na-EMAA was added. DSC results ofNy6/Na-EMAA binary blends showed tha with increasing Na-EMAA content, the crystallization temperature of Ny6 hpase decreased, indicating that Na-EMAA retarded the crystallization of Ny6. Melting point depression was found in both the Ny6 and LDPE phases in the ternary blends, indicating that Na-EMAA interfered with the crystallization of both blends. From the results, it can be concluded that during melt blending chemical and/or physical reactions have taken place between Ny6 and Na-EMAA, which confirmed by Molau test. compared to our previous work, the Na+ carboxylate inomers are a more effective compatibilizer than the Zn2+ inomers; however the copolymer itself was different between the Na+ and Zn2+ materials so the comparison between the two cations is a direct one. Still however, this work show that sodium-neutralized materials do serve as effective compatibilizers for nylon and LDPE.