Study of Elastomer Structure Microdefects by Positron Annihilation

A complex lifetime and angular correlation study of positron annihilation in a wide range of polymers and elastomers is carried out. Pick-off annihilation from the localized states is found to be the main mechanism of positron annihilation in the studied elastomers. Influence of elementary free volumes of polymer structure as well as of chemical composition (presence of polar groups) of polymer chain elements on the concentration of positron traps is considered. Effective sizes of positron traps are found ranging from 6 up to 15 A. It is demonstrated that the nature of positronsensitive centres is determined by the distortions in polymer chains packing close to the rigid, side groups and in places of deviations of shape of polymer chains from the linear one. [Russian Text Ignored].

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