Study and quantitative assessment of the structural inhomogeneities parameters of composite materials

The possibility of determining the size of the delamination region and the depth of its location in non-metallic multilayer weakly conductive materials using a unique pulsed eddy-current equipment by scanning the sample and registering the region of increasing amplitude of the differential signal has been practically confirmed. The nonstationary thermal and holographic interferometry method is used to obtain information on the shape and size of the bundles. For experimental testing, samples were used made of carbon fiber composite materials with artificially created defects in the structure of the material in the form of delaminations of various sizes and shapes.

WOOD-GLASS-FIBER COMPOSITE MATERIALS BASED ON POLYESTER RESINS FOR TIMBER RAILWAY SLEEPER STRUCTURES

Wood-glass-fiber composite materials (WGFCM) are used in transport construction (sleepers, switch bars, etc.). Polymer solutions based on furfuralacetone monomer (FAM) served as a matrix for the manufacture of WGFCM. The article suggests using Holex HAS- 2061 polyester resin as a matrix, which, in turn, has chemical resistance, dielectric properties, increased impact strength, having sufficient strength characteristics, and significant extensibility. For the application of the above material in the structural elements of sleepers of logging railways, it is necessary to know its operation under repeated loading. Endurance experiments were conducted at different coefficients of the load application cycle asymmetry pb=0,1; 0,3; 0,6. As a result of the experiments, the values of the endurance limit of the material under study were obtained, which allow us to conclude that it can be used in the construction of timber railway sleepers.

An Overview of the Design of Chitosan-Based Fiber Composite Materials

Chitosan composite fibrous materials continue to generate significant interest for wastewater treatment, food packaging, and biomedical applications. This relates to the relatively high surface area and porosity of such fibrous chitosan materials that synergize with their unique physicochemical properties. Various methods are involved in the preparation of chitosan composite fibrous materials, which include the modification of the biopolymer that serve to alter the solubility of chitosan, along with post-treatment of the composite materials to improve the water stability or to achieve tailored functional properties. Two promising methods to produce such composite fibrous materials involve freeze-drying and electrospinning. Future developments of such composite fibrous materials demands an understanding of the various modes of preparation and methods of structural characterization of such materials. This review contributes to an understanding of the structure–property relationships of composite fibrous materials that contain chitosan, along with an overview of recent advancements concerning their preparation.