Structural approach to the study of deformation mechanism of amorphous polymers

Abstract

A new microscopic procedure for the visualization of structural rearrangements in amorphous polymers during their deformation to high strains is described. This approach involves the deposition of thin (several nanometers) metallic coatings onto the surface of the deformed polymer. Subsequent deformation entails the formation of a relief in the deposited coating that can be studied by direct microscopic methods. The above phenomenon of relief formation provides information concerning the deformation mechanism of the polymer support. Experimental data obtained with the use of this procedure are reported, and this evidence allows analysis of the specific features of structural rearrangements during deformation of the amorphous polymer at temperatures above and below its glass transition temperature under the conditions of plane compression and stretching, uniaxial tensile drawing and shrinkage, rolling, and environmental crazing. This direct structural approach originally justified in the works by Academician V.A. Kargin appears to be highly efficient for the study of amorphous polymer systems.

Plastic deformation of polyethylene terephthalate films during rolling

“…was described in [29][30][31][32]. This technique consists of applying a nanometer metallic coating to the surface of a polymer.…”

Visualization of structural rearrangements during annealing of solvent-crazed isotactic polypropylene

“…How ever, progress in this direction is limited by the absence of any direct experimental methods for studying the evolution of structural rearrangements in the course of deformation. In recent years, a new microscopic pro cedure has been proposed [1][2][3][4]; the use of this proce dure makes it possible to gain direct information on the above structural rearrangements and offers new knowledge concerning the deformation mechanism of amorphous polymers at temperatures below [5] and the above glass transition temperature [6]. In particu lar, annealing of PET samples oriented above the glass transition temperature was accompanied by both shrinkage and elongation along the direction of pre liminary tensile drawing, the so called phenomenon of spontaneous self elongation [6,7].…”

“…In particu lar, annealing of PET samples oriented above the glass transition temperature was accompanied by both shrinkage and elongation along the direction of pre liminary tensile drawing, the so called phenomenon of spontaneous self elongation [6,7]. In this case, after annealing, the resultant length of the sample is smaller as compared with its initial length, but the use of the above microscopic procedure allows a direct and vivid visualization of the spontaneous self elongation of PET under the above conditions [1][2][3][4].…”

“…In our recent works, we have used this microscopic procedure to study structural rearrangements in the course of deformation and annealing of amorphous glassy polymers after solvent crazing or, in other words, after their tensile drawing in the presence of adsorptionally active liquids environments [8][9][10].…”

Correlation between relief formation and structural rearrangements during annealing of oriented amorphous polymers with metallic coating

“…Recently, a direct microscopic technique has been developed that makes it possible to solve this problem in many respects [4][5][6][7]. In general terms, this technique of visualization of structural rearrangements is based on one of the most fundamental properties of solids.…”