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Information × Registration Number 0218U006688, 0117U006556 , R & D reports Title A new approach to mechanical rejuvenation of polymeric glass based on the formation of a long time of plasticity popup.stage_title Head Voznyak Andrei, Registration Date 16-07-2018 Organization Donetsk National University of Economics and Trade named after M.Tugan-Baranovsky popup.description2 Polymer glass, as a rule, is in an unbalanced state, and as a result, there is a constant movement towards thermodynamic equilibrium (physical aging). One of the negative consequences of such a process is that over time the material becomes fragile (because of small changes in the conformation of the chain, local intermolecular interactions increase, which leads to an increase in the resistance of the plastic flow). The basic idea is that a large-scale, segmental movement, induced by mechanical loads, creates a free volume. Since physical aging is associated with a gradual collapse of free volume, the deformation-induced free volume should wash off part of the previous physical aging. One of the mechanisms of plastic deformation of polymers is craze formation, which is propagated by an increase in the volume of polymer samples through the decompositions of macroscopic porosity. For this reason, mechanical rejuvenation of vitreous polymers is usually carried out at room temperature which is much lower than the glass transition temperature at which the change of the deformation mechanism from crack formation to plastic displacement takes place. It is assumed that, above the glass transition temperature, plastic deformation occurs through the mechanism of plastic shear, which is characterized by the flow of a continuous medium, without the formation of an additional volume (internal surface). The main purpose of the project is to study the effectiveness of the processes of mechanical rejuvenation, which occur at high deformation temperatures. As a research object, polylactide is used, which is an extremely fragile polymeric material. The research results are useful for a fundamental understanding of how the processes of mechanical rejuvenation influence the process of physical aging of polymeric glasses and the kinetics of the aging process. In addition, understanding the process of physical aging of vitreous polymers, as well as its kinetics, is important for the industrial application of polymeric glasses that are used in the technique. Product Description popup.authors А.О. Возняк Ю.А. Горяйнова Ю.В. Возняк popup.nrat_date 2020-04-02 Close