The choice of adhesive for the production of yarn glue method

It is proposed to use sericin, a component of silkworm cocoons, as an adhesive compound for the production of yarn by the adhesive method. An experiment was conducted to study the dependence of the adhesion forces of the binder to cellulose on the concentration of the adhesive substance on the example of solutions of PVA, PVA and sericin. A comparative analysis of this dependence is carried out. Mathematical models are constructed to predict the strength of the adhesive joint depending on the concentration of the adhesive composition. The calculation of the adhesion forces per one elementary fiber is carried out.

Biological And Chemical Properties of Cured Epoxy Resins

Introduction: Launched into production over 50 years ago, epoxy resins aroused enormous interest owing to their valuable properties that distinguish them from other polymeric materials. The investigation of biological and chemical effects of direct exposure to the materials under study on the human body may help in the organization of work when dealing with this type of materials.Objectives: The objective of this study is to investigate selected biological and chemical properties of 3 cured epoxy compounds: Epidian 53 epoxy resin with polyaminoamide C curing agent, Epidian 53 epoxy resin with polyaminoamide C curing agent, and aluminum powder, and Epidian 53 epoxy resin with polyaminoamide C curing agent, and copper powder. Methods: The experimental part of this paper describes the preparation and fabrication of adhesive compound samples, from a liquid state to cured plates. The study involved a cytotoxicity analysis (with an ELSA reader), pH measurements (with a pH meter), absorbance measurement over an entire reference wavelength range, and sterilization (on a specially designed test bench) along with microscopic examination of its effects.Results: Cytotoxicity and absorbance analysis results demonstrate that extracts of all tested resin samples do not have cytotoxic effect on the cells of living organisms. The absorbance results over the wavelength range do not indicate the formation of aggregations, which proves that no toxic agents harmful to living organisms are extracted from the resin samples.Conclusion: Results of this study demonstrate that cured epoxy resins are safe materials.

Selection substantiation of mechanical treatment method of machine part surfaces to be glued with metal-filled adhesive compounds

In production and repair of mechanical engineering products, poor preparation of surfaces for gluing leads to a decrease in adhesion or even to the destruction of the adhesive bond. The level of strength of the adhesive bond is determined not only by the absence of contamination on the surfaces to be bonded, but also largely depends on the type of materials to be bonded, the properties of the adhesive used and the geometric parameters of the surface. The analysis results of the quality and roughness of aluminum and steel surfaces obtained by various methods of machining are discussed. The shear test results for adhesive joints are presented. The tests were carried out on adhesive joints of aluminum and steel substrates, the surfaces of which were treated with sanding belts with grit sizes P40, P80 and P120 before gluing. A metal-filled adhesive compound based on epoxy resin with the addition of 3% aluminum powder (by weight) was used as the glue. The character of destruction of the studied adhesive joints is described. Recommendations on method srelection for machining aluminum and steel materials before gluing are presented.

Adhesive compound of composite materials in conditions of accelerated climatic aging

Introduction. Pultruded fiberglass can be called the material of the future due to its properties — high strength, low weight, resistance to aggressive environment. Important aspects for the development of composite materials are surface treatment methods and methods of connecting structural elements. Glue compound has proven itself as the most effective, but there remains a need to conduct studies of its durability. The method of accelerated cyclic thermal tests allows to determine the expected changes in the strength of adhesive bonding in a short time. Materials and methods. Samples, which are three glued plates of SPPS fiberglass construction, were processed in a climate chamber and after each cycle they were tested on a GRM-1 machine. One climatic test cycle included being in a chamber with high humidity and temperature and then moving into the cold chamber. The specimens were tested prior to spalling, and the resulting disruptive stresses were recorded. The last test cycle corresponded to five years of operation of the structure. Results. The tests of the samples showed a significant change in the characteristics of the compounds over time. In the first two years of operation, a decrease in strength of 25 % is expected. The last characteristic test point, corresponding to five years, showed a drop to 60 % of the initial characteristics. Conclusions. The results should be considered at the design stage of supporting structures that are not protected from contact with the external environment. The factors of strength reduction after 100 years may be included in the regulatory documents for the calculation of especially important structures.

Experimental clinical study on the using of adhesive in the obliteration of varicose veins in humans

Introduction. In order to perform endovasal vein lining, the American Rodney D.Raabe developed a system for varicose veins obliteration, consisting of a glue gun and two catheters, called “VenaSeal”. As an occlusant for varicose veins in this system, “Medtronic” company today proposes to use an adhesive compound synthesized on the basis of butyl ether of α-cyanacrylic acid.Materials and methods. Endovasal catheter obliteration of tributaries and main trunks of the great saphenous vein on the tibia was performed in 15 patients with varicose disease (C2 to CEAR) in order to substantiate the possibility of using the adhesive compound Sulfacrylate. Severity of pain, presence or absence of phlebitis and thrombophlebitis, hyper pigmentation, neurological disorders, allergic reaction were clinically evaluated.Results and discussion. All patients after the introduction of the glue Sulfakrilat had a clinic of moderate phlebitis, without the formation of blood clots in the lumen of the vein. No local or general allergic reaction was observed. From day 7 occluded venous segments were palpated in the form of moderate density bands, without infiltration to surrounding tissues. In the absence of blood flow ultrasound examination showed gradual biodegradation of the adhesive strip inside the vein with the development of complete obliteration of the lumen starting from the 4th month. Starting with the 7th day gradually stopped aseptic inflammation in the wall of the vein was observed on histological examination. Monocytic infiltration of the venous wall with the formation of multinucleated cells of foreign bodies was present until the time of complete biodegradation of the glue. The process of diffuse growth of connective tissue with the presence of fibroblasts from the subendothelium and in the middle shell was most actively observed in histological material from 90 to 120 days after occlusion. Within 180 days, the lumen of the veins occluded by “Sulfacrylate” was completely obliterated by mature connective tissue, in the absence of glue particles, which indicated its complete biodegradation.Conclusion. The experimental studies conducted with the assessment of clinical symptoms, ultrasound examination and histological study of morphogenesis in the lumen of blood vessels in different periods up to 6 months allow us to conclude the potential use of the adhesive compound “Sulfacrylate” (produced in Russia) for endovasal obliteration of varicose veins in humans.

Validation of the calculation of a wooden column with a support unit on glued steel plates

The article proposes a structural solution for the base of a wooden frame column on flat links glued in the support part of the column – steel plates welded to the base plate. The results of numerical studies of the column, taking into account the parameters of the adhesive connection of the plates with wood and the anisotropy of wood, are presented. The column model takes into account the geometric and physico-mechanical characteristics of wood, steel plate bonds and adhesive compound. The main results of numerical studies are verified with the results of the analytical calculation of the column performed by the method of initial parameters. A physical model with the proposed structural solution of the column base was made and tested. The numerical and analytical calculations of the column were validated, and the main conclusions of the experimental and theoretical study were presented.

Alternative Briquette Material Made from Palm Stem Biomass Mediated by Glycerol Crude of Biodiesel Byproducts as a Natural Adhesive

Recently, the global population has increased sharply, unfortunately, the availability of fossil fuel resources has significantly decreased. This phenomenon has become an attractive issue for many researchers in the world so that various studies in the context of finding renewable energy are developing continuously. Relating to this challenge, this research has been part of scientific work in the context of preparing an energy briquette employing palm oil stems and glycerol crude of biodiesel byproducts as inexpensive and green materials easily found in the Riau province, Indonesia. Technically, the palm oil stems are used for the production of charcoal particles and the glycerol crude as an adhesive compound in the production of energy briquettes. The heating value of palm oil stem is 17,180 kJ/kg, which can be increased to an even higher value through a carbonization process followed by a densification process so that it can be used as a potential matrix to produce energy briquettes. In detail, this study was designed to find out several parameters including the effect of sieve sizes consisting of 60, 80, and 100 mesh, respectively, which are used for the preparation of charcoal particles as the main matrix for the manufacture of the briquettes; the effect of charcoal-adhesive ratios (wt) of 60:40, 70:30, and 80:20; and the effect of varied pressures of 100, 110, and 120 kg/cm2 on the briquette quality. The quality of the obtained briquettes is analyzed through the observation of important properties which involve the heating value and the compressive strength using Response Surface Methodology (RSM). The results showed that the produced briquettes had an optimum heating value of 30,670 kJ/kg, while their loaded charcoal particles resulted from the mesh sieve of 80, in which there was a charcoal loading of 53 g and it pressed at 93.1821 bar, whereas, the compressive strength value of the briquette was 100,608 kg/cm2, which loaded charcoal particles from the mesh sieve of 100, the charcoal-adhesive ratio of 53:47 (wt) and the pressure of 93.1821 bar.

Study of the possibilities of 3D printing in ship modeling using the example of manufacturing a model of a small vessel for hydrodynamic testing in an experimental pool

The relevance of the work is determined by a fundamentally new direction of 3D printing in the manufacture of ship models for hydrodynamic testing. In this paper, we study the towing drag of a model of a small boat manufactured using additive three-dimensional printing technologies. Based on the dimensions of the 3D printers used and the technological parameters of working with them, as well as the design features of the test pool, small-sized vessels of a series of kayaks, kayaks and canoes, which are of sufficient length, but not too wide and high, were investigated as a prototype of the future model, which is ideal under the methods of additive manufacturing. A base of prototypes of vessels of this class has been compiled and a rationale has been given for the choice of the prototype vessel itself for research, including an analysis of the design of the vessels presented, the availability of design and technological documentation, as well as technological schemes for manufacturing the model. A 3D model of the vessel was developed, its optimization for 3D printing and analysis of geometric shapes for deviations from ITTC requirements. The study of deviations of the geometric shapes of the ship model from shrinkage deformations was carried out using 3D scanning with the development of a technological scheme for describing this process. When developing a 3D model, in the process of 3D printing, as well as processing the results of 3D scanning, modern software tools — FreeShip, Autodesk Inventor, Cloud Compare, and others — were used in the work. In the manufacture of the model, the new DPA adhesive compound formula was used, able to provide durable joints for PLA plastic products. It was found that the measurements prove the possibility of using 3D printing for the production of ship models for hydrodynamic testing, subject to all the nuances of the technology.

The Effect of the Salt Water Aging on the Mechanical Properties of Epoxy Adhesives Compounds

The objective of this study is to compare the effect of selected operating factors on the mechanical properties of epoxy adhesive compounds aged in salt water. Five different water environments were tested: tap water, normal seawater (reference salinity value), seawater with double reference salinity value, seawater with half of the reference salinity and seawater with a quarter of the reference salinity value. Samples of two different adhesive compounds were prepared using the epoxy resin and triethylenetetramine curing agent. One of the compounds was filled with calcium carbonate. The samples were aged in five different water environments for three months, one month and one week, respectively. Mechanical properties of the cured adhesive compound samples were determined via strength tests performed on the Zwick/Roell Z150 testing machine in compliance with the EN ISO 604 standard. The objective of the experiments was to determine the effect of different seawater environments on selected mechanical properties (including strength) of the fabricated adhesive compounds.

Advanced analytics of elastic adhesive bonds by means of in situ computed tomography

This paper addresses optimization of parameters and measuring setups for in situ computed tomography measurements on marker particle-filled adhesives. The focus of this work was to increase the detail detectability and discriminability between used marker particles and surrounding adhesive compound even for materials with a high X-ray attenuation. Therefore, it is necessary to reduce the effects of artifacts like scattered X-rays and beam hardening, respectively. A key benefit of being able to distinguish different materials clearly improves the correct interpretation of the reconstructed three-dimensional volume significantly, while a reduction of artificial disturbances enhances the possibility to visualize previously overlaid undetected details, e.g. air voids. Performing in situ computed tomography measurements by applying the optimized parameter setups, cavitation formation was observed investigating the particle behavior of specimens modified with glass beads as marker particles under applied load. An achieved bonding enhancement by using a coupling agent as pre-treatment for glass beads was also proven by means of in situ computed tomography. Furthermore, the parameter setups optimized for bulk specimen could be adapted on material combinations, e.g. single-lap shear specimen, by adjusting a few parameters. Additional experiments demonstrate that computed tomography measurements can also be used for analytical purposes, for instance to evaluate the mixing quality of the so-called QUADRO™ or 2C mixers for two-component adhesives.