Temperature dependence of the degree of compatibility in SBR-NBR blends byultrasonic attenuation measurements: influence of unsaturated polyester additive

The dependence of ultrasonic attenuation coefficient on temperature is meas ured for styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NB R) and their blends (SBR/NBR = 25/75, 50/50, 75/25 by wt) in the temperatur e range from 240 to 342 K at ultrasonic frequency of 5 MHz. The obtained ul trasonic relaxation peaks due to glass-rubber transition were used to inves tigate the degree of compatibility (DC) in the blends as well as its variat ion with temperature. The addition of 10 phr of unsaturated polyester resin (based on p-carbethoxy phthalanilic acid and maleic anhydride with ethylen e glycol) to the blend showed improvement of DC in certain temperature rang es and deterioration of DC in other temperature ranges. (C) 2001 Elsevier S cience Ltd. All rights reserved.