Climatic Ageing Of Organic Fiber Reinforced Plastics: Water Effect

Старцев, О. В.; Krotov, A. S.; Mashinskaya, G. P.

doi:10.1080/00914039708031483

Cited by 18 publications

(4 citation statements)

References 4 publications

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“…After the exposure in the full-scale climatic conditions, the moisture transfer parameters increase. A general regularity is an increase of the values of M∞ and D at a drying stage of the moisture-saturated samples in comparison with the corresponding values of these parameters under humidification due to physicochemical transformations in the epoxy matrix of BPA with moisture plasticisation [19]. Similar effects were observed earlier for other PCMs based on the epoxy polymers [21].…”

Section: Resultssupporting

confidence: 80%

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Influence of moderately warm and extremely cold climate on properties of basalt plastic armature

Startsev

Лебедев

Кычкин

2018

Heliyon

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Rods of basalt plastic armature (BPA) of a periodic profile with diameters of 6, 8, 10, 16 and 20 mm on the basis of an epoxy matrix were exposed for 30 months on open stands in a moderately warm marine climate of Gelendzhik and 28 months on similar stands in an extremely cold climate of Yakutsk. For initial and exposed BPA samples, changes of mechanical parameters were determined. After the exposure in Yakutsk, an increase of ultimate compression strength by 4–12% is found, depending on the diameter of rods. After the exposure in Gelendzhik, this indicator decreases by 10–17%. Using methods of thermomechanical analysis and dynamic mechanical analysis, linear thermal expansion coefficient and glass transition temperature of epoxy matrix were measured. In an initial state, a transition from a glassy state to a highly elastic one is discovered: an α1-transition at 118 °C and an α2-transition at 149 °C. After climatic action, there were detected a shift of α1-transition to low temperatures and a shift of α2-transition to higher temperatures. Reasons for the change of temperatures of transitions are weakening of a molecular layer and post-curing of the epoxy matrix in a surface layer. These effects are accompanied by an increase of the linear thermal expansion coefficient, moisture diffusion coefficient and maximum moisture saturation after the climatic action on BPA. Fractographic studies discovered presence of pores in a structure of BPA with sizes up to 10–20 μm, a quantity and size of which increase by 20–40% after the climatic action. In general, the studied BPA has high climatic stability and can be used for a long time under the extreme climatic conditions.

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Section: Resultssupporting

confidence: 80%

“…According to [18, 19, 20], the glass transition temperature Tg of the polymer matrix is a sensitive indicator of the climatic aging of polymer composite materials (PCM). The method of dynamic mechanical analysis (DMA) was used to determine this parameter.…”

Section: Methodsmentioning

confidence: 99%

Influence of moderately warm and extremely cold climate on properties of basalt plastic armature

Startsev

Лебедев

Кычкин

2018

Heliyon

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“…Quantitative values of the glass transition temperature determined using the method of dynamic mechanical analysis, as well as the duration of the accumulated time intervals depending on the season are given in Table 1. Along with quantitative environmental parameters, the moisture content of the samples at the time of direct testing is considered as a factor that has a direct impact on the mechanical strength of epoxy polymers [5,6,13,14]. In particular, it is known that in the process of full-scale climatic aging, the mass of the exposed polymer samples irreversible increases which is described by some researchers from the point of view of eliminating the initial structural disequilibrium [2,[14][15][16].…”

Section: Resultsmentioning

confidence: 99%

Natural Climatic Aging of Epoxy Polymers Taking into Account the Seasonality Impact

Nizin

Nizina

Selyaev

et al. 2019

KEM

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The change in the elastic-strength and sorption properties of epoxy polymers in the process of natural aging, taking into account the sequence of different climatic seasons effects, was studied. We studied polymers obtained on the basis of low-viscosity epoxy resins and a hardener, which is a mixture of aromatic and aliphatic di-and polyamines, modified by salicylic acid. Differences in the processes of structural relaxation and elimination of the initial nonequilibrium depending on the season of the exposure start are revealed. Mathematical models that describe changes in the elastic-strength properties of epoxy polymers during climatic aging, depending on the accumulated quantitative values of the acting environmental factors, have been developed. For the first time, it was proposed to use as a variable parameter the total duration of time intervals for the studied period the surface temperature of the samples at which exceeded the glass transition temperature.

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“…To clarify the causes of PCM aging the following effects are usually studied: plasticization of polymer matrices by atmospheric moisture [ 33 , 34 ]; swelling (increase in thickness) of samples when adsorbing moisture [ 35 ]; destruction of polymer matrices affected by solar UV radiation and air oxygen [ 32 , 36 ]; hydrolysis of polymer matrices affected by moisture [ 37 , 38 , 39 ]; recoating of polymer matrixes under the influence of temperature and the plasticizing effect of moisture [ 20 , 39 , 40 ]; misorientation of organic fibers affected by solar UV radiation, thermal and moisture cycling, and mechanical loads [ 39 ]; structural relaxation and shrinkage of the fibers forming the frame of the reinforcing filler [ 20 , 39 , 40 ]; physical aging and structural relaxation of polymer matrices [ 41 , 42 ]. …”

Section: Introductionmentioning

confidence: 99%

Contributing Factors of Uneven Climatic Aging for Polymeric Composite Materials: Methods and Modelling

et al. 2023

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Regarding a wide variety of PCMs, the materials’ strength properties which decrease no more than 20% after 30 years of operation are of special interest. One of the important regularities of the climatic aging of PCMs is the formation of gradients of mechanical parameters across the thickness of the plates. The occurrence of gradients must be taken into account when modeling the strength of PCMs for long periods of operation. At present, there is no scientific basis for the reliable prediction of the physical-mechanical characteristics of PCMs for a long period of operation in the world of science. Nevertheless, “climatic qualification” has been a universally recognized practice of substantiating the safe operation of PCMs for various branches of mechanical engineering. In this review, the influence of solar radiation, temperature, and moisture according to gradients of mechanical parameters across the thickness of the PCMs are analyzed according to the data of dynamic mechanical analysis, linear dilatometry, profilometry, acoustic emission, and other methods. In addition, the mechanisms of uneven climatic PCM aging are revealed. Finally, the problems of theoretical modeling of uneven climatic aging of composites are identified.

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Climatic Ageing Of Organic Fiber Reinforced Plastics: Water Effect

Cited by 18 publications

References 4 publications

Influence of moderately warm and extremely cold climate on properties of basalt plastic armature

Influence of moderately warm and extremely cold climate on properties of basalt plastic armature

Natural Climatic Aging of Epoxy Polymers Taking into Account the Seasonality Impact

Contributing Factors of Uneven Climatic Aging for Polymeric Composite Materials: Methods and Modelling

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