Polymer composites based on polystyrene and modified SiO2 are synthesized. Effect of the SiO2 concentration on the surface (thermostatic) properties of the composites is analyzed. Surfaces of composites with different SiO2 concentrations are microscopically studied. Minor amounts of spherical agglomerates are obtained at relatively high SiO2 concentrations, and the size of the agglomerates may amount to 80 μm at a SiO2 concentration of 30 wt %. Variations in the integral absorbance of solar radiation are studied for the polymer composites irradiated with vacuum-UV radiation at a temperature of 125°C.

Modification of Optical Characteristics of a Polymer Composite Material under Irradiation

The article presents a comparative characterization of the structural materials (composites and metals) used in modern aviation structures, focusing on the airframe structure of the most modern aircraft (Airbus A-380, Boeing B-787, and JSF F-35). Selected design and operational problems were analysed, with particular emphasis on composites and light metals (aluminium). For this purpose, the Shore’s method was used for the analysis of the obtained strength results and the programming environment (ANSYS, SolidWorks) required to simulate the GLARE 3 2/1-04 composite. The focus was on highlighting the differences in the construction and modelling of these materials resulting from their various structures (isotropy and anisotropy), e.g., by analyzing the mechanics of metal destruction and comparing it with the composite material. In terms of solving the problems of finite element analysis FEM, tests have been carried out on two samples made of an aluminium alloy and a fiberglass composite. The focus was on highlighting the differences in the construction and modelling of these materials resulting from their various structures (isotropy and anisotropy), e.g., by analyzing the mechanics of metal destruction and comparing it with the composite material. On the basis of the obtained results, the preferred variant was selected, in terms of displacements, stresses, and deformations. In the final part of the work, based on the conducted literature analysis and the conducted research (analysis, simulations, and tests), significant observations and final conclusions, reflected in practical applications, were formulated.

Practical Use of Composite Materials Used in Military Aircraft.

Relative variations of nonlinear elastic moduli in polystyrene-based nanocomposites

In this research, an analysis of polymer composite with the matrix of L285-cured hardener H286 and six reinforcement layers of carbon fabric GG 280 T was provided. It involved a comparison of the dynamical behavior responses for three cases of composite structures in the context of the presence of the mass share modifier. The samples with the addition of a physical modifier with varying mass percentages were investigated by being subjected to dynamic tests with specific parameters, i.e., constant excitation amplitude and vibration frequency in the vicinity of the base resonance zone. The analysis allowed for indicating the relationship between the composition of the prepared composites and their dynamic response via stiffness characteristics. In addition, the investigation resulted in determining the range of harmful dynamical operating conditions, which may contribute to damage to the composite structures.

https://www.mdpi.com/1996-1944/13/23/5479/pdf

Influence of the Selected Physical Modifier on the Dynamical Behavior of the Polymer Composites Used in the Aviation Industry

In this study, poly(monoethylene diglycol sebacate) with a low molecular weight was synthesized from the reaction of ethylene diglycol and sebacic acid. The melt condensation reaction of the prepared polyester diol with citric acid produced a bioelastomer material comprising a network of transparent and flexible polyether esters. This material was amorphous, with a glass transition temperature of lower than 0°C. Its mechanical properties (tensile strength, 1.92–4.61 MPa; elongation at break, 201.9–348.9%) and degradation performance could be tuned by changing the molar ratio of the reacting monomers and controlling the crosslink curing time of the prepolymer. As a biological material, the as-synthesized elastomer showed good hydrophilicity, water-absorption capability, and dimensional stability.

Synthesis and characterization of a novel biodegradable elastomer based on citric-acid-crosslinked polyesters

Nanocomposites consisting of a polymethylmethacrylate or polystyrene matrix with embedded silicon dioxide nanoparticles surface-modified by silazanes have been prepared by melting technology. The influence of particles on viscoelastic properties of the nanocomposites has been studied using dynamic mechanical analysis. It has been revealed that the addition of 20 wt % of SiO2 raises the flexural modulus of the nanocomposites by 30%.

V. E. Smirnova

Papers

Mechanical properties of polymeric composites with carbon dioxide particles