Application of gamma-quanta angular correlation method to study strain-stressed hollow fibers

Parallel studies of polypropylene (PP) deformed samples, using the method of angular correlation of γ-quanta and acoustic method, have been carried out to evaluate possibilities of positron method and to compare the results obtained with the gas permeability of the samples tested. Heat treated hollow fibers of isotactic PP have been studied using a device with parattet-siot geometry in the range of angles theta=-15 to +15 mrad with the pitch 0.5 mrad. The fiber permeability under tension is determined by volumetric method. Results of helium permeability changes in the process of sample tension are presented. It is established that fiber permeability increases under tension, which testifies to the formation in the fiber walls of the system of communicating pores. Spectra are presented of angular correlation of γ-quanta of PP-fibers under tension normalized for the similar area. Dependences of the intensity and half-width of the narrow component on deformation, as well as dependences of ultrasound propagation rate on deformation at the rates 3 and 40%/min are considered