Synergism in properties of ionomeric polyblends based on zinc salts of carboxylated nitrile rubber and poly(ethylene-co-acrylic acid)

Ionomeric polyblends of zinc oxide neutralized carboxylated nitrile rubber, abbreviated as Zn-XNBR and zinc oxide neutralized poly(ethylene-co-acrylic acid), abbreviated as Zn-PEA, were prepared in the compositions ranging from 90/10 to 50/50, in parts by weight. Out of these blends, compositions of 90/10, 80/20 and 70/30, in parts by weight, behave as ionic thermoplastic elastomers. While synergism in tear strength and hardness is observed in all the three compositions, the Zn-XNBR/Zn-PEA blend ratios of 90/10 and 80/20 show synergism in tensile strength. The ionomeric polyblends show higher physical properties than the corresponding non-ionomeric polyblends. Infrared spectroscopic studies show that ionic interaction is more prominent in the blends than in the neat ionomers. Dynamic mechanical thermal analyses show the occurrence of a high temperature transition due to the relaxation of the restricted mobility region adjacent to the ionic domains. Reprocessability studies show that the ionomeric polyblends could be reprocessed without deterioration in strength. (C) 1999 Elsevier Science Ltd. All rights reserved.