Thermogravimetric analysis of glue-welded joint with various adhesive materials

Using the IR-thermography methods, the experimental evaluation of temperature transitions in a steel and aluminum glue-welded joint made with applying various adhesive materials (epoxy, anaerobic, organic-silicon and hot melt glue) has been carried out. It was found out that viscosity of an adhesive material considerably effected on the temperature transitions in the glue-welded joint as well as on glue line thickness. The temperature transitions were demonstrated on different sections of the glue-welded joint. Conclusions were made about the influence of properties of adhesive materials on the glue-welded joint quality.

Application prospect of impregnating compounds for maintenance of suspension components of road machines under different temperature conditions

The application possibility of impregnating compounds for maintenance of rubber components of a pneumatic suspension of road machines under different temperature conditions has been assessed. Solid oil (the cheapest general-purpose plastic grease) and anaerobic material of AN-1U grade (richer impregnating compound) were used as impregnating compounds. It was found out that the use of impregnating compounds for maintenance of rubber components of a pneumatic suspension of road machines made possible to increase their resistance to the effect of negative temperatures, to minimize material cracking and as a result to increase service life of the suspension.

Strength of glued-welded joints under long effect of negative temperature

The experimental test results of strength of glued and glued-welded joints at room and negative temperatures after long exposure of them at –30 °С and –50 °С are presented. As glue materials, epoxy adhesive, anaerobic adhesive-sealant, silicone sealant and adhesive-melt based on copol-ymer of ethylene with vinyl acetate were used, as substrates, steel and aluminum alloy samples were used. It has been found out that silicone sealant ensures the best strength of glued-welded joints at low temperatures. It was determined that for all the studied types of the glued-welded joints, strength at –30 °С was worse than at –50 °С.

Estimation of load-carrying ability of pressure adhesive couplings

The experimental test results of glued-mechanical couplings of shaft — bush made with the use of anaerobic sealants are presented. Quantitative estimations of the surface layer quality of the mating parts were obtained that made possible to estimate values of surface waviness of the shaft and the bush. The methodology of the waviness determination of cylindrical couplings is described. The influence of fit on mechanical strength of the shaft — bush coupling depending on properties of a used anaerobic sealant was established.

Influence of paper type on processes of impregnation and lamination of wood-based boards

The results of studies evaluating the influence of a type of penetrated paper on the processes of impregnation and hot lamination of wood-based board materials are presented. A woodchip board was used as a base to carry out the hot lamination for the finishing process of materials. After this process, the woodchip board is named «laminated woodchip board». Papers of different manufacturers, papers’ main properties and technological characteristics were tested.

INFLUENCE OF UV RADIATION ON PHYSICAL-MECHANICAL CHARACTERISTICS OF FILAMENT-WOUND EPOXY GFRP BASED ON EPOXY MATRICES

The effect of ultraviolet radiation on the physical-mechanical characteristics of filament-wound glass-fiber reinforced plastic (GFRP) based on an epoxy matrix has been studied. During 45 days, a decrease in strength of GFRP when stretching and bending takes place. However, the compressive strength increases. IR spectroscopy has shown that the change in the properties of composites occurs as a result of photo-oxidative degradation of the epoxy matrix.

INFLUENCE OF MULTIPLE CURING ON MECHANICAL PROPERTIES OF EPOXY MATRIX AND ITS ADHESION TO FIBERS

Adhesive strength of «epoxy binder-steel wire» joints and the mechanical behavior of the binder during multiple repeated curing have been investigated. It is shown that when the curing temperature is considerably higher than the glass transition temperature of the binder, the adhesive strength decreases monotonically with an increase in the number of curing cycles. In this case the mechanical properties of the matrix also decrease. Possible mechanisms of the observed changes are discussed.

Properties of composites based on melamine-formaldehyde binders

The properties of impregnating compounds used for lamination of timber-based board materials consisting of import ingredients and resins c 35-40% melamine content have been examined. A synthesis technology of melamine-formaldehyde impregnating resins with 25-30% melamine content and domestic ingredients is presented. It is shown that paper-resin films produced with the use of modified impregnating resins are high-quality facing material for decoration of timber-based board products by the lamination method.

Evaluation of resistance of silicone sealant to ultralow temperature effect

Properties of the silicone sealant VGO-1 have been examines, which is used for production of glue-welded joints made by contact welding. Conditions to produce glue-welded joints are described. It was found out that when welding steel specimens of the 08kp brand on the VGO-1 sealant there was a decrease in a welding current value and an increase in welding time and the electrode compression force. The study of sealant structures after storage at different temperatures demonstrated that the used sealant had good resistance at –30 °С in the air environment and satisfactory resistance at –50 °С in a liquid environment. The swelling index of the sealant after 20 day storage in medicinal ethyl alcohol was no more than 4.5%.

Chemical durability of glass-reinforced plastics based on epoxy binders with curing agents Etal

Studies of chemical durability of a glass-reinforced plastic produced with the use of an epoxy binder with the curing agents Etal-45M, Etal-M7, Etal-23Kh under conditions of boiling in water and storage at 95 °С in 10% NaOH solution have been carried out. It was found out that glass-reinforced plastics with the binders Etal-45M and Etal-23Kh were the most stable to the influence of the aggressive environments.