Melt rheology of ethylene ionomers blended with a small-molecule acid

A novel EMAA ionomers with the incorporation of low molecular weight carbox ylic acid have been developed to reduce melt theology without changing the complete transparency of ionomers. Here, a blend of EMAA-59Zn (93 wt%) and montanic acid (MA, C27H55COOH 7 wt%) was investigated in terms of TGA, DSC, FT-IR, and dynamic shear viscosity. A good heat stability of MA during mel t blending preparation and melt viscosity measurement was confirmed by TGA. DSC showed only one peak (86.9 degreesC) for the blend sample, and FT-IR e xhibited additional peaks (1545, 1625 cm(-1)) by the blending. These facts suggested that the blend is a homogeneous mixture and the blend induced an additional new coordination structure between Zn and carboxylic acid. Dynam ic melt theological measurement exhibited a significant decrease of storage modulus and loss modulus by the blending. The reduction of melt theology w as more than the addition of plasticizing effect and the decrease of neutra lization. The newly induced coordination structure implies a relationship w ith the unexpected additional reductions. (C) 2001 Elsevier Science Ltd. Al l rights reserved.