Effect of Physico-Chemical Factors on the Propagation of Water Trees in Polyethylene

The action, type, and concentration of salts in solution in water on the propagation of water trees in polyethylene has been studied using the water needle method and a visualization system allowing measurements under electric stress. Some possible mechanisms for the action of the salts are discussed: effect of salt concentration on the conductivity of the solution, effect of by-products from electrochemical reactions at the electrode, and the effect of polyethylene oxidation at the water-polymer interface.