MODEL RESINS LEADING TO A CONTROLLED POLYMER PHASE MORPHOLOGY

Nowadays the demand for a well defined property set of rubber products is fulfilled by blending of rubbers and by addition of reinforcing fi llers as well as low molecular weight additives. The morphology of the complex multicomponent mixing system has a dominating influence on th e properties of the final product but is by today not sufficiently kno wn and taken into consideration. Apart from the rheological history, t he morphology is governed by the composition of the distinct phases wh ich can show strong variations in polarity by adding low molecular wei ght substances, among which chemically and physically insufficiently c haracterized technical softener oils and hydrocarbon resins are the mo st important in amount. Therefore structure-property relationships can not be achieved to get some necessary information about the equilibriu m distribution of technical oils and resins in polymer blends and dedu ce morphological variations. This contribution deals with chemically w ell defined model substances containing aromatic, naphthenic and paraf finic structural elements to study their effect on the phase morpholog y and properties of blends of general purpose rubbers (NR, BR, SBR). O n the basis of the experimental results it will be shown how changes i n morphology can be controlled by structural elements and molecular we ight of the model resins used.