Papers by Keyword: Adhesive Strength

Abstract: One type of birch plywood production by-product: plywood sanding dust (PSD) and virgin polypropylene (PP) composites adhesive activity was investigated. To improve of the WP (PP+40 wt.% PSD) composites sheets as overlay bonding strength against birch plywood surface and water resistance of these laminated systems the industrially produced WPC material was modified with maleated polypropylene wax (MAPP) additives. These studies showed possibility of the usage of presented by-product as an excellent reinforcement for PP based wood plastic composites and addition of the coupling agent (MAPP) gives the considerable increase of adhesive activity of the used WPC. Due to the presence of MAPP (up to 4%) significantly increases not only adhesive strength of the laminates but also water resistance of the laminated sandwich specimens. As the example adhesive bonding strength could reach 2,74 N/mm2 and increases up to 4 times to compare with unmodified WPC adhesives.

Abstract: The strength characteristics of polymer composites (PCM) reinforced with fibers of various nature largely depend on the adhesion strength of the components in the matrix-fiber contact zone, determined by the mechanisms of their adhesive interaction. The strength of the bonds in the contact zone depends on the transfer of the load from fiber to fiber through the matrix layer. Taking into account the order and greater strength of the reinforcing fibers in tension, compared with the matrix material, the adhesion of the PCM components has the greatest effect when the material is perceived as transverse to the direction of the fiber loads, which usually occurs in bending and interlayer shear. In the latter case, the strength of the material several times less, which determines the importance of increasing the strength of the adhesive interaction, which requires comprehensive studies and an adequate description of its mechanisms. An experimental study of the adhesion strength in the matrix-fiber contact zone after short-term exposure to a microwave electromagnetic field with different energy flux densities on the PCM physical cell model, represented as a basalt fiber bundle placed in ED-20 epoxy resin, was performed. It has been established that exposure to a microwave electromagnetic field with an energy flux density of (17-18) x10⁴ μW/cm² for 1-2 minutes leads to an increase in adhesion relative to the source material by no less than 32%. This method can be used as a basis for the development of technologies for increasing the strength of the interlayer shear PCM, reinforced by fibers of various nature. To clarify the mechanisms of the obtained results, it is advisable to conduct a study of the micro-and nanostructures of the “matrix-fiber” contact zone using electron and atomic-force microscopy and its phase composition..

Abstract: In this article the various methods of assessment of gas-thermal coating’s adhesion strength are considered. The methodology of carrying out the strength tests, using traditional methods of quantitative assessment of adhesive strength of a coating towards its basement, is reflected; the advantages and disadvantages of the represented methods are given. In the article, the theoretical justification of the mechanics of adhesive avulsion is given, and the imperfection of conic pins’ usage is shown. Aiming at increasing of the accuracy and quality of the strength tests of gas-thermal coatings, a modernised methodology, as well as the samples (а.с.1436025), related to detection of the adhesion strength, are suggested. The theoretical computation of the reasonableness of usage of ring cross section of the coating, resulted in the event of usage of the offered sample, is given. On the basis of theoretical computation, a defining formula of the adhesive strength is conducted. Comparison tests of adhesion strength with various sample’s designs are completed. The reasonableness and effectiveness of usage of the offered methodology in assessment of gas-thermal coating’s adhesion strength are proven.

Abstract: The article is intended to convince the reader of the need to characterise the contact of the adhesive with the substrate. The concept of contact layer and intensity of adhesive interaction is introduced. The specific examples demonstrate the effectiveness of the proposed approach for solving boundary problems with stress concentration The Cauchy problem in this case is strictly solved.

Abstract: Expressed viscoelasticity of polymeric materials which can develop over a long period of time prevents their widespread. Some types of polymers, such as epoxy resins, can be used to connect various structural elements. The destruction in this case can be caused by the growth of tangential stresses in the adhesive joint and their achievement of some critical value τ_adhezive, at which the adhesive joint is destroyed.

Abstract: We adduce the information about methodology of decision-making on conformity of quality of the painted surface of building products and constructions to the established requirements. General methodology consists of obtaining, analyzing the facts on the normalized indicator and calculation and establishment of the norm.When calculating the allowed value of the adhesive strength can be determined for 3-σ deviation from mathematics expectation. The maximum permissible values of average-quadratic deviation should be determined by standard value coefficient of variation. Formulas are given for determining the permissible value of the coefficient of variation. The normative values of the coefficients of variation for some protective and decorative coatings are given

Abstract: Aim of this study focused on insert injection molding process, which is molded the melted polymer around an inserted part placed in the molded cavity of injection molding process. The interfacial adhesive strength between the inserted and an injected polymer parts were investigated by Intron universal test machine in order to investigate the effect of material in inserted and injected part. During tensile testing the acoustic emissions (AE) measurement was applied to evaluate the fracture behavior of insert injection molding. It was found that interfacial adhesive strength of insert injection molded of all specimens increased according with increasing the bonding area of adhesive interface. The fracture mode of the insert injection molded specimens was depended on the length of bonding area of the inserted part. The fracture of mode of the insert-injection molded specimens was confirmed by acoustic emission.

Abstract: Tooth enamel cannot be naturally reconstructed once it is destroyed immoderately. Therefore, the restoration of enamel is important in dental treatment. Hydroxyapatite (HAp) can potentially be used for a novel dental biomaterial to repair the enamel. We have proposed a tooth restoration technique with intraoral laser ablation method. A thin layer of HAp was deposited on dentin surface in the atmosphere by ablation phenomenon using an Er:YAG (Erbium: Yttrium-Aluminum-Garnet) laser irradiated to the target of α-tricalcium phosphate (α-TCP). Then, the deposited layer was hydrolyzed by dripping pure water on its surface in order to create HAp film. The adhesive strength between the HAp film and dentin was evaluated by quasi-static tensile tests. As a result of the mechanical evaluation, the adhesive strength was greater than approximately 3.8 MPa. It is clear that the HAp film created by the Er:YAG laser ablation method is attached tightly to the dentin.

Abstract: Fused deposition modeling (FDM) is one of the most widely used technologies in rapid prototyping. On the principle of layered manufacturing, the melted polymer filament is extruded and formed. In order to achieve transition from nonfunctional prototypes to functional prototypes of FDMed models, using the RepRap Kossel delta 3D printer and 1.75mm diameter polylactic acid (PLA) filament, it was analyzed that the effects of the nozzle moving rate and slice thickness on adhesive strength based on the existing technology research by orthogonal test. The experiment results indicated that adhesive strength of filament increased both with the nozzle moving rate and with its slice thickness. The latter induced increase more significantly. Finally, comprehensive experiments had been performed to quantitatively study the adhesive strength variation with the filling rate, which provides data reference for setting proper filling rate. Reasonable filling rate setting can not only satisfy the strength requirement without debasement of printing quality, but also reduce filament consumption, improve the manufacturing efficiency and provide important instruction significance for actual printing.

Abstract: Model of the film-substrate interface of diamond coatings is built with the method of molecular dynamic, and the molecular dynamic simulation is applied to study the mechanical property of the model based on the Morse potential function and Tersoff potential function with temperature ranging from 0K to 800K. The results show that the adhesive strength of the interface between the diamond coatings and the cemented carbide substrate behaves a downward trend when the temperature rises from 0K to 800K and the downward trend is sharp when the temperature increases from 0K to 300K and the downward trend is smooth when the temperature rises from 300K to 800K. Meanwhile, the varying trend of the energy with the temperature is similar to the adhesive strength.