Morphology, mechanical and thermal behavior of acrylate rubber/fluorocarbon elastomer/polyacrylate blends

Novel thermoplastic elastomers derived from binary and ternary blends of polyfunctional acrylates, acrylic rubber (ACM) and fluorocarbon rubber (FKM) were analyzed by using Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC), Dynamic Mechanical Thermal Analysis (DMTA) and mechanical tests. TEM revealed the presence of a single-phase structure for both acrylate rubber/fluorocarbon elastomer (ACM/FKM) and ACM/polyacrylate binary blends. Increase of FKM concentration in the ACM/FKM/polyacrylate ternary blend resulted in phase separation of FKM from the ternary blend. The FKM formed a dispersed phase with polynodal particle distribution and irregular shape ranging from ellipsoidal to highly elongated form with inclusion of ACM. The FKM/polyacrylate binary blend showed complete phase separation. Ageing of the blend increased the domain size of the dispersed phase. Differential scanning calorimetric (DSC) and DMTA studies showed no major changes in the T(g)s of individual polymers in the blend, although the peak tan delta values were affected on changing the composition of the blends. Vulcanization of the thermoplastic elastomer (TPE) changed the phase morphology with increase in particle size. There is a distinct difference in morphology of statically and dynamically vulcanized blends. (C) 2002 Kluwer Academic Publishers.