Aging of Polymer Composites in Extremely Cold Climates

Abstract

A review of studies of effects of temperature, moisture, solar radiation, and other aggressive environmental factors on the properties of polymer composite materials are presented to substantiate the mechanism of their aging in extremely cold climates. It has been shown that composites develop internal stresses caused by unequal thermal expansion of reinforcing fibers and polymer matrices. These internal stresses cause the occurrence of microcracks, their coalescence, and formation of macro-damages in the bulk of the binder or at the interface with fibers. Fiberglass, carbon fiber, and other reinforced materials exposed to climatic conditions can accumulate water in pores and capillaries, which can turn into a solid phase at temperatures below 0 °C and increase internal stresses. Even in cold climates, the surface of materials undergoes destruction and microcracking under the impacts of UV components of solar radiation, thus increasing the number of sources of internal stresses. The mechanical properties of composite materials deteriorate under the effects of seasonal and daily thermal cycles.

Development and research of basalt plastic material for the flood protection structures

“…1.09 Note: *I -initial state, K-2 -after 2 years of exposure, K-4 -after 4 years of exposure Analysis of the experimental results shows an increase in the plastics mechanical properties after 2 years of exposure on the open stands in Yakutsk. It is known that such an increase in the PCM persistence indicators is due to the polymer matrix post-curing and complies with the results obtained by the other researchers [19][20][21][22][23].…”

Research of Moisture Sorption by Laminated Composite Materials

“…Engineering Materials: Properties and Processing Technologies When carrying out the process of water absorption for 20 days on the initial specimens BFL and GFL, an increase in thickness was observed up to 1,5 % and 1,9 %, respectively. An increase in mass after moisture desorption of BFL specimens by 0,023 %, GFL by 0,027 % and after exposure to BFL by 0,037 %, GFL by 0,026 % confirms the assumption about the binding of a certain amount of water molecules in BFL [2,5] and GFL [1,[3][4][6][7][8]]. An increase in moisture absorption values during climatic tests is associated with the processes of destruction and weathering of the polymer binder in the surface layer, the growth of microcracks deep into the material and an increase in the number of micropores.…”

“…It is known that water absorption depends not only on the chemical composition of PCM, but also on the method of obtaining the finished product [7-8, 11, 15]. PCM obtained by winding methods, contact, vacuum, autoclave formation has a significant amount of microcracks and pores (more than 4%), in which rapid capillary condensation occurs [7][8]15]. The stepped contour of the curve for BFL and GFL specimens immersed in water is presumably related to the difference in adhesion in the "polymer-filler" system at the points of contact between the warp and weft and the penetration of water molecules into the formed defects, edge effects, as well as the absorption of water by the fibrous filler.…”

“…Among the factors that negatively affect the structural performance of polymer composite materials (PCM), the impact of moisture is especially prominent [1][2][3][4][5][6][7][8][9][10]. As you know, the decrease in the strength of PCM occurs as a result of physicochemical processes occurring in the polymer matrix and the polymer-filler interphase layer [1][2][3][4][5][6][7][8][9][10][11][15][16]. The degree of changes in strength indicators depends on the type and content of the binder and filler [10][11][13][14][15], the technology for obtaining PCM [11][12][13][14][15], etc.…”

“…A significant part of studies on the study of the effect of moisture on the strength characteristics of PCM is devoted to the effect of atmospheric moisture during thermal and moisture aging [1,[4][5][6][7][8][9][10]. At the same time, the aging processes occurring in the material must be comparable, both when tested in laboratories and in natural conditions.…”