Melt Rheology of Low-Density Polyethylene/Polyamide 6 using Ionomer as a Compatibilizer

Rheology of blends of polyamide 6 with low-density polyethylene compatibilized with sodium-, zinc-, and lithium-neutralized ethylene-methacrylic acid ionomers were investigated at 11, 33 and 55% neutralization of ionomer. Blends of polyamide 6 with low-density polyethylene without compatibilizer had lower shear viscosities than a mixing rule would predict. After adding compatibilizer, the shear viscosity of the blend is increased, presumably due to the formation of graft copolymer from the reaction of the primary amine with free acid groups. The increase of shear and elongational viscosity properties is less with EMAA than with the ionomers; which is consistent with mechanical property and dispersed phase size results presented in an earlier publication. For high polyamide 6 content blends, zinc-neutralized compatibilizers yielded the highest shear and elongational viscosities; while for low polyamide 6 contents, lithium-neutralized compatibilizers yielded the highest viscosities.