Selective cross-linking of carboxylated acrylonitrile butadiene rubber and study of their technological compatibility with poly(ethylene-co-methyl acrlylate) by means of mechanical, thermal, and chemical analysis

Abstract: Technologically compatible blend becomes an interesting arena of polymer blend industry for their significant properties and fascinating morphologies. This work encompasses the fabrication of technologically compatible blend through melt blending of poly(ethylene-co-methyl acrylate) (EMA) and carboxylated acrylonitrile butadiene rubber (XNBR) in five different ratios to study their compatibility by employing various techniques, like Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). To observe the reinforcing effect of blend specific amount of metal oxide, zinc oxide (ZnO) was incorporated into the system. Curing characterization, FTIR, and morphological analysis confirm that ZnO selectively forms cross-link with XNBR through the coordination complex and does not show any substantial effect on EMA. DMTA reveals high-temperature relaxation of the carboxylic salt of XNBR phase which reinforces the EMA/XNBR _{ZnO-cross-linked} blends and also verified by FTIR analysis. Although DSC shows single glass transition temperature (T _g ) for all blend systems in between the T _g of pure polymer component, DMTA confirms the presence of two different T _g for plastic and rubber phases with close proximity, specifying technological compatibility in blend compounds. Increasing XNBR improves tensile strength of blends by sacrificing elongation at break. Therefore, our aim is to tune and optimize the blend features by judicial mixing of EMA and XNBR to mitigate the blend failure during service tenure and develop a novel technologically compatible blend.