Laminar polymer composites for wooden structures
The lack of a clear regulatory framework governing the use of polymer composites to strengthen wooden structures, stimulates the conduct of numerous studies in this area. An important task is to obtain reinforcing materials with the best physico-mechanical and operational parameters. The choice of the type of curing adhesive has a great influence to characteristics of polymer composites such as viscoelastic parameters of the material, adhesion properties on the contact surfaces, the presence of internal defects, etc. The paper describes a method for determining the physicomechanical characteristics of a composite material based on experimental studies. The stand, test samples and the pattern array of tensometric sensors for testing according to Russian State Standard GOST R 56800-2015 "Polymer composites. Determination of tensile properties of unreinforced and reinforced materials have been presented. Dependences of stress-strain, modulus of elasticity, Poisson's ratio, tensile strength for laminate polymer composite have been obtained. Comparative analysis of the obtained results for various adhesive compositions has been performed. According to the results of experimental studies, it was found that the physicomechanical characteristics of polymer composites based on epoxy matrix are higher than those of polyurethane matrix composites due to uniform filling of the filler volume, as well as better wettability of the reinforcing fibers. In conclusion, the article draws conclusions about the effect of the adhesive composition on the mechanical characteristics of the obtained composites have been made, relevance and applied significance of the investigation for strengthening the compressed-flexural elements of wooden structures has been justified.