Degradation of polystyrene by shear stress in isopropylphenyl phosphate solution

The molecular weight distribution functions of polystyrene degraded by shear stress in isopropylphenyl phosphate solution were compared with the calculated ones, obtained by assuming that up to a certain distance from each chain end the probability of bond scission is zero. Two phenomenological models were proposed for the probability of degradation in the central part of the chain. A comparison with experimental data suggests that the probability of degradation increases towards the center of the chain. Branched fractions formed by degradation in the presence of air were found to be present by the GPC method with on‐line viscometric detection.