Effect of Immersion in Water or Alkali Solution on the Structures and Properties of Epoxy Resin
| Autor: | Guijun Xian, Bin Wang, Chenggao Li, Dihui Li |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
chemistry.chemical_classification
Absorption of water Materials science Polymers and Plastics Diffusion water or alkali solution Organic chemistry General Chemistry Epoxy Polymer Fibre-reinforced plastic Alkali metal Article epoxy resin structural evolution Hydrolysis QD241-441 chemistry Chemical engineering tensile strength visual_art Ultimate tensile strength visual_art.visual_art_medium water uptake |
| Zdroj: | Polymers, Vol 13, Iss 1902, p 1902 (2021) Polymers Volume 13 Issue 12 |
| ISSN: | 2073-4360 |
| Popis: | The durability of fiber-reinforced polymer (FRP) composites is significantly dependent on the structures and properties of the resin matrix. In the present paper, the effects of physical or chemical interactions between the molecular chain of the epoxy resin matrix and water molecules or alkaline groups on the water absorption, mechanical structures, and microstructures of epoxy resin samples were studied experimentally. The results showed that the water uptake curves of the epoxy resin immersed in water and an alkali solution over time presented a three-stage variation. At different immersion stages, the water uptake behavior of the resin showed unique characteristics owing to the coupling effects of the solution concentration gradient diffusion, molecular hydrolysis reaction, and molecular segment movement. In comparison with the water immersion, the alkali solution environment promoted the hydrolysis reaction of the epoxy resin molecular chain. After the immersion in water or the alkali solution for one month, the water uptake of the resin was close to saturate, and the viscoelasticity was observed to decrease significantly. The micropore and free volume space on the surface and in the interior of the resin gradually increased, while the original large-scale free volume space decreased. The tensile strength decreased to the lowest point after the immersion in water and the alkali solution for one month, and the decrease percentages at 20 °C and 60 °C water or 60 °C alkali solution were 24%, 28%, and 22%, respectively. Afterward, the tensile strength recovered with the further extension of immersion time. In addition, it can be found that the effect of the alkali solution and water on the tensile strength of the epoxy resin was basically the same. |
| Databáze: | OpenAIRE |
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