In this study, polyurethane/polyurea coatings were exposed to four different types of aging: aging in the natural environment (NC), accelerated ultraviolet aging (UV), aging in a sodium chloride solution (NaCl), and thermal aging (TC). To monitor the changes that occurred during these processes, the thickness was measured and microscopic and macroscopic observations were conducted continuously. The samples aged under various conditions were then subjected to spectroscopic (FTIR) and thermal (TGA) analysis to determine the possible structural changes in the coatings. The dependence of aging conditions on the physicochemical properties of the tested coating surfaces was thoroughly investigated and characterized by the water contact angle and surface free energy. Adhesion tests were performed after the established aging period. The results show that different aging conditions have a tremendous effect on the appearance and pull-off strength. The coatings that age in a NaCl solution are more affected in terms of their adhesion.

The paper analyzes the issues relating to the applicability of innovative material systems for flexible composite armors. The authors made several samplings of aramid fibers (Kevlar 49) by replacing the epoxy resin base, which is often described in the literature, with the thermoplastic matrix - polyethylene (HDPE) and polypropylene (PP). The samples were fired with .38 Special Full Metal Jacketed (FMJ) ammunition produced by the S&B Company, and then the process of firing was modeled in the ABAQUS program. The advantages and disadvantages of the new material system including the possibility of its use in the construction of hybrid composite armors have been presented on the basis of the results of numerical analyses and ballistic tests.

This paper focuses on the manufacturing and quality evaluation of fibre-reinforced polymer matrix composite coatings deposited by hand lamination on DC04 steel substrates. Two matrices (polyurethane and epoxy resins) and four different reinforcement materials were considered (glass, carbon, aramid, and carbon-aramid hybrid fabrics). Various methods of surface preparation and roughness development were used in order to enhance the adhesion: cleaning with acetone, abrasive blasting with F80 alumina or GH40 cast steel shot. Manufactured samples were subjected to roughness and coating thickness measurements, wettability analysis, and pull-off strength tests. Afterwards, the microscopic analysis of cross-sections of the samples and the identification of type of the failure were performed. The increase in surface roughness was beneficial, to some point, for the coating’s adhesion. The highest pull-off strength values were obtained for polyurethane coating reinforced with glass fabric after abrasive blasting with the use of F80 alumina (5.78 MPa) and epoxy resin with aramid reinforcement (5.20 MPa) after pretreatment with GH40 cast steel shot.

The influence of surface roughness on adhesive joint strength for polymer coating reinforced with various fabrics to aluminum substrate was investigated. PA11 aluminum alloy was chosen as the substrate, which was prepared in two different methods: degreasing with acetone or abrasive blasting. Two different abrasives (F80 fused alumina or GH40 cast steel grit) were used for mechanical treatment to obtain different roughness parameters. The coatings were made of two matrices (polyurethane and epoxy resins) and four different reinforcement materials (glass, carbon, aramid, and carbon-aramid hybrid fabrics). The manufactured samples were subjected to roughness and coatings’ thickness measurements, wettability evaluation, and pull-off strength tests. Various mechanisms of detachment were observed. The increase in substrate roughness had a positive effect on the pull-off strength. The highest pull-off strength values were obtained for unreinforced polyurethane coating (4.46 MPa) and epoxy resin with glass fabric (3.07 MPa) after pretreatment with abrasive blasting with the use of F80 fused alumina.

The paper aims at presenting the results of pull-off strength tests of fiber-reinforced polymer composite coatings laminated on steel substrates. It contains the measured data on the thickness of manufactured coatings and the substrate surface’s roughness, according to the various methods of surface’s preparation with the means of abrasive blasting. The microstructure analysis of material’s cross-sections and damage analysis of samples after failure were also performed. The highest pull-off strength’s values for composite coatings were obtained for joints with the substrate modified by abrasive blasting with corundum F60 or simply degreased. To establish the compatibility of substrates with coatings the wettability of the chosen materials was tested and work of adhesion was calculated on its base. Concerning the wettability, it was found that the most preferable joints were characterized by the similar thermodynamic work of adhesion and consisted of the coating’s matrix (SBS) and the steel substrate degreased with acetone or modified with corrundum abrasive blasting and then degreased.