| Abstract: | A study of the dynamic viscoelastic properties of gels of Ethylene Vinyl Acetate (EVA) and Styrene‐Butadiene‐Styrene (SBS) copolymers in recycled motor oil is presented. Both systems form gels with enhanced elastic moduli, with respect to SBS/aromatic oil gels which have been used to develop synthetic binders. Although the procedure described by Winter is conveniently applied to obtain gel‐sol transition of EVA/oil gels, it is not suitable for SBS/oil gels which do not give rise to a homogeneous liquid when they melt. For EVA/oil gels the relaxation exponent at the gel point is Δ=0.5, which according to Muthukumar's model corresponds to a fractal dimension df=2. The variation of the elastic modulus with polymer concentration follows the scaling law Ge‐cn, with n=2.8 for EVA/oil and n=1.3 for SBS/oil. In the case of EVA/oil gels the validity of theoretical models relating fractal dimension to n exponent is discussed. |
