STRUCTURE AND MORPHOLOGY OF FILLED RUBBER AND THERMOPLASTIC ELASTOMERS

Element spectroscopic imaging (ESI) technique in transmission electron microscopy (TEM) has been used to investigate the morphology and fill er distribution in thermoplastic polyurethane (PUR) elastomers and fil led rubbers. Single filler particles could be identified and imaged by ESI-TEM. Elastic bright field images of samples containing zinc stear ate as a vulcanization accelerator showed a change in the morphology a fter vulcanization. An influence of the mixing time on the tiller dist ribution was found in that silica agglomerates and inhomogenities in t he distribution of zinc oxide and titanium dioxide appeared at longer mixing times. The microphase separated morphology of segmented PUR ela stomers could be visualized by imaging the net nitrogen distribution. The ESI micrographs of polyether urethanes with monodisperse or polydi sperse hard segment distribution indicated a dramatic change in the ha rd domain morphology from relatively uniform cylinder domains (monodis perse hard segment) to more irregular and lamellar structures in polyd isperse systems.