Effect of the Type of Adhesives on the Properties of Multilayer Packaging Material Based on PET/AlOx Film with Acrylic Coating before and after the Sterilization Process

In this work the properties of multilayer packaging materials based on PET/AlOx film with acrylic coating were studied. Multilayer packaging materials were produced on industrial laminators using three different adhesive compositions with different content of reactive groups. It is shown that the peculiarity of the chemical nature of adhesive components affects the bond strength and the seal strength of multilayer packaging materials.

Properties of Eco-Friendly Particleboards Bonded with Lignosulfonate-Urea-Formaldehyde Adhesives and pMDI as a Crosslinker

The purpose of this study was to evaluate the feasibility of using magnesium and sodium lignosulfonates (LS) in the production of particleboards, used pure and in mixtures with urea-formaldehyde (UF) resin. Polymeric 4,4′-diphenylmethane diisocyanate (pMDI) was used as a crosslinker. In order to evaluate the effect of gradual replacement of UF by magnesium lignosulfonate (MgLS) or sodium lignosulfonate (NaLS) on the physical and mechanical properties, boards were manufactured in the laboratory with LS content varying from 0% to 100%. The effect of LS on the pH of lignosulfonate-urea-formaldehyde (LS-UF) adhesive compositions was also investigated. It was found that LS can be effectively used to adjust the pH of uncured and cured LS-UF formulations. Particleboards bonded with LS-UF adhesive formulations, comprising up to 30% LS, exhibited similar properties when compared to boards bonded with UF adhesive. The replacement of UF by both LS types substantially deteriorated the water absorption and thickness swelling of boards. In general, NaLS-UF-bonded boards had a lower formaldehyde content (FC) than MgLS-UF and UF-bonded boards as control. It was observed that in the process of manufacturing boards using LS adhesives, increasing the proportion of pMDI in the adhesive composition can significantly improve the mechanical properties of the boards. Overall, the boards fabricated using pure UF adhesives exhibited much better mechanical properties than boards bonded with LS adhesives. Markedly, the boards based on LS adhesives were characterised by a much lower FC than the UF-bonded boards. In the LS-bonded boards, the FC is lower by 91.1% and 56.9%, respectively, compared to the UF-bonded boards. The boards bonded with LS and pMDI had a close-to-zero FC and reached the super E0 emission class (≤1.5 mg/100 g) that allows for defining the laboratory-manufactured particleboards as eco-friendly composites.

Effect of Technical Aerosil on the Properties of Adhesive Compositions

The main drivers of competition among the products made with the use of adhesive compositions are the toxicity of finished products, the consumption of raw materials and energy resources, the duration of the main technological operations. These drivers can be controlled by using adhesives with different fillings and/or modifications. Adhesives based on phenol-formaldehyde and melamine-urea-formaldehyde resins are used to produce plywood with increased water resistance. Apart from resins, adhesives usually contain hardeners, fillers, and modifiers that affect the properties of the finished product. Technical aerosol is one of the modifiers of synthetic resins with a wide range of action. Aerosil is characterized by three types of interaction: physical adsorption, chemical adsorption (formation of hydrogen bridges by silanol groups), and chemical reactions on the surface layer. The chemical composition of aerosil was analyzed. Technical aluminum fluoride (AlF3) is of particular interest. It can interact with alkali metal fluorides with the formation of complex compounds that improve polymer structuring. The acids that make up aerosil reduce the pH to 2.0–3.5, so they can be catalysts for the curing process of melamine-urea-formaldehyde resins. The effect of technical aerosil on the properties of adhesive systems based on phenol-formaldehyde and melamine-ureaformaldehyde resins has been studied. Viscosity, curing time, and wetting ability of adhesive compositions were determined. The obtained results indicate the possibility of using this modifier in the composition of phenol-formaldehyde and melamine-urea-formaldehyde resins up to 15 pts. wt. The nature of the aerosil action on adhesive compositions was determined using IR spectroscopy. Analysis of the results showed that aerosil promotes deep structure formation of the polymer by increasing the molecular weight of the molecules. These bonds make it possible to form a more structured polymer with bound formaldehyde. Studies of the effect of aerosil on the properties of finished products were carried out. At the same time, an increase in performance indicators was found: the strength of adhesion increases, the toxicity of plywood decreases. The results of experiments on the effect of technical aerosil, taking into account the reduction of bonding time can be applied in the development of technological processes for obtaining plywood of high water resistance. For citation: Sokolova E.G., Rusakov D.S., Varankina G.S., Chubinsky A.N. Effect of Technical Aerosil on the Properties of Adhesive Compositions. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 133–144. DOI: 10.37482/0536-1036-2021-3-133-144

Mechanical Properties of Epoxy Compounds Based on Bisphenol a Aged in Aqueous Environments

(1) Background: The aim of the work is to determine the influence of selected aqueous environments of various types of liquids on the strength of adhesive compositions prepared from epoxy resin based on bisphenol A combined with two different curing agents: tritethylenetetramine and polyaminoamide C. (2) Methods: The cured epoxy adhesive compounds samples were seasoned in four aqueous environments of the liquid: rainwater, demineralized water, tap water, and a sweetened drink. Three variants of the aging time in the above-mentioned operating environments were adopted: one month, two months, and three months. After the specified maturing time, samples of epoxy adhesive compositions were subjected to the strength tests on the Zwick/Roell 150 testing machine, which is in accordance with ISO 604 standard, determining the compressive strength. (3) Results: On the basis of the obtained strength test results and their analysis, it was noticed, inter alia, that the strength of the epoxy compounds decreases with the aging time in all used aqueous environments. Moreover, in the case of both types of the epoxy compounds, the highest strength was achieved after aging in demineralized water.

Influence of polymer coatings on icing of ship structures

Полимерные покрытия находят все более широкое применение в судостроении и судоремонте. Этому способствует многообразие полимерных покрытий с различными свойствами. Одним из распространённых требований, предъявляемым к корпусным конструкциям морских судов является необходимость обеспечения их безотказной работы в условиях воздействия отрицательных температур окружающей среды. При интенсификации процессов обледенения возможно возникновение аварийных ситуаций. В статье рассмотрены различные аспекты влияния полимерных покрытий на обледенение судовых корпусных конструкций. Приведены экспериментальные зависимости адгезии льда к металлу и полимерам от солености воды, от величины шероховатости. Установлено, что изменение шероховатости поверхностей и соленость воды существенно влияют на адгезию полимерных покрытий ко льду. Выявлены клеевые композиции, обеспечивающие полимерным покрытиям наименьшую адгезию ко льду. Исследования позволяют дать рекомендации по совершенствованию методов ремонта и модернизации судовых корпусных конструкций. Polymer coatings are increasingly used in shipbuilding and ship repair. This is facilitated by the variety of polymer coatings with different properties. One of the most common requirements for marine hull structures is the need to ensure their trouble-free operation under the influence of negative environmental temperatures. With the intensification of the processes of icing possible the occurrence of accidents. The article deals with various aspects of the influence of polymer coatings on the icing of ship hull structures. Experimental dependences of ice adhesion to metal and polymers on water salinity and roughness are presented. It was found that changes in surface roughness and water salinity significantly affect the adhesion of polymer coatings to ice. Adhesive compositions that provide polymer coatings with the lowest adhesion to ice are identified. The research makes it possible to give recommendations for improving the methods of repair and modernization of ship hull structures.

The Influence of Mixing Methods of Epoxy Composition Ingredients on Selected Mechanical Properties of Modified Epoxy Construction Materials

The proper process of preparing an adhesive composition has a significant impact on the degree of dispersion of the composition ingredients in the matrix, as well as on the degree of aeration of the resulting composition, which in turn directly affects the strength and functional properties of the obtained adhesive compositions. The paper presents the results of tensile strength tests and SEM microphotographs of the adhesive composition of Epidian 57 epoxy resin with Z-1 curing agent, which was modified using three fillers NanoBent ZR2 montmorillonite, CaCO3 calcium carbonate and CWZ-22 active carbon. For comparison purposes, samples made of unmodified composition were also tested. The compositions were prepared with the use of six mixing methods, with variable parameters such as type of mixer arm, deaeration and epoxy resin temperature. Then, three mixing speeds were applied: 460, 1170 and 2500 rpm. The analyses of the obtained results showed that the most effective tensile results were obtained in the case of mixing with the use of a dispersing disc mixer with preliminary heating of the epoxy resin to 50 °C and deaeration of the composition during mixing. The highest tensile strength of adhesive compositions was obtained at the highest mixing speed; however, the best repeatability of the results was observed at 1170 rpm mixing speed. Based on a comparison test of average values, it was observed that, in case of modified compositions, the values of average tensile strength obtained at mixing speeds at 1170 and 2500 rpm do not differ significantly with the assumed level of significance α = 0.05.

INFLUENCE OF THE COMPOSITION AND CONDITIONS OF HEAT TREATMENT OF THE CONDUCTIVE PROPERTIES OF SILVER-CONTAINING ELECTRICALLY CONDUCTIVE ADHESIVE COMPOSITIONS (review). Part 1

Data on the use of various types of silver filler in electrically conductive adhesive compositions are presented. The influence of form and size particles of silver filler on the conductive properties of adhesive bondline. The effect of surface treatment of conductive particles with surfactants, the component composition of the resin part and the curing conditions of conductive adhesive compositions on their microstructure and conductive properties is shown. An overview of the results of studies of the microstructure of conductive silver-containing adhesive compositions is given.

INFLUENCE OF THE COMPOSITION AND CONDITIONS OF HEAT TREATMENT OF THE CONDUCTIVE PROPERTIES OF SILVER-CONTAINING ELECTRICALLY CONDUCTIVE ADHESIVE COMPOSITIONS (review). Part 2

The influence of the chemical nature and component composition of the polymer base and the curing conditions of conductive adhesive compositions on their conductive properties is shown. The values of the volumetric shrinkage during the curing of the adhesive are compared with the realized level of conductive properties. The influence of the temperature level during curing on the electrical conductivity of the cured glue is shown. Shrinkage phenomena, viscosity, temperature range of the curing reaction were investigated as factors determining the appearance and formation of the conductive properties of conductive compositions during curing.