Study of the abrasion resistance of wood-polymer composites and mixtures of ABS-plastic with polyvinyl chloride

The abrasion of materials based on blends of ABS plastic with polyvinyl chloride (PVC) as well as terraced boards based on wood-polymer composites (DPC) has been studied. The measurements were carried out on a drum-type machine, and on a Taber's abrasimeter. For blends of ABS plastic with PVC at abrasion path length 600 m wear is 0.85%. For terracotta boards based on WPC, the wear during the test (loss of mass) was 0.0042 g. The abrasion of the sample was 9.29×10-5 g/cm2. Thus, the obtained blends should be recommended for application for floor coverings, since they possess negligible abrasion

Stress-optical coefficients of copolymers

The stress-optical coefficient Cσ of copolymers based on cured epoxy resins has been calculated. Calculations were made for epoxy resins based on bisphenol A and aliphatic and aromatic diamines. The Cσ values are in the range of 91.6÷103 weight percent. All calculations were carried out using the Cascade computer program (developed by INEOS RAS). The investigated structures of cured epoxy resins are obtained from industrial components. High Cσ values make it possible to confidently use the mentioned network polymers in the photoelasticity method, from which models of full-scale building structures can be made

Newest models and calculation schemes for quantitative analysis of physical properties of polymers

New models and calculation schemes have been developed for the quantitative analysis of a number of physical properties of polymers — glass transition temperature, flow temperature of polymer nanocomposites, thermal conductivity, boiling point of polymer solutions, water absorption and water permeability of polymers and nanocomposites, strength, viscosity, storage and losses moduli, refractive index and dielectric constant. All calculation schemes are based on the structure of linear and cross-linked polymers; their degree of crystallinity, free volume, the effect of temperature, the composition of copolymers and homogeneous mixtures of polymers, the concentration of nanoparticles, their shape, size distribution, orientation angles, the structure of polar groups grafted to the surface of nanoparticles, the energy of intermolecular interactions are taken into account. All computational schemes are computerized and allow calculations to be carried out automatically after the introduction of the structure of a repeating unit of polymer unit into the computer, as well as the shape and size of nanofillers

Water absorption of wood-polymer composites of savewood

The materials based on wood-polymer composites (WPC) in the form of decking boards are produced, in which wood filler is partially replaced by mineral one. WPC materials manufactured by Savewood using a matrix polymer of polyvinyl chloride (PVC) have good mechanical properties, low abrasion and satisfactory resistance to climatic influences. However, they have relatively high water absorption, the task of reducing which is relevant not only in Russia, but also in other countries where there are constructions of facilities operating in outdoor environmental conditions. The modification of such materials in this work was carried out by replacing part of the wood filler with the mineral filler, which is CaCO3 (chalk). Partial replacement of wood flour with mineral filler resulted in a marked reduction in swelling from 1.25 to 0.01%. In this case, the modulus of elasticity is increased from 2260 to 2880 MPa, tensile strength from 30.5 to values of 16.7 ÷ 32 MPa. The specific impact strength varies from 8.90 to 7.74 kJ/m2. The optimal ratio of wood and mineral fillers is 60/40%.</jats:p

Water absorption of wood-polymer composites of savewood

The materials based on wood-polymer composites (WPC) in the form of decking boards are produced, in which wood filler is partially replaced by mineral one. WPC materials manufactured by Savewood using a matrix polymer of polyvinyl chloride (PVC) have good mechanical properties, low abrasion and satisfactory resistance to climatic influences. However, they have relatively high water absorption, the task of reducing which is relevant not only in Russia, but also in other countries where there are constructions of facilities operating in outdoor environmental conditions. The modification of such materials in this work was carried out by replacing part of the wood filler with the mineral filler, which is CaCO3 (chalk). Partial replacement of wood flour with mineral filler resulted in a marked reduction in swelling from 1.25 to 0.01%. In this case, the modulus of elasticity is increased from 2260 to 2880 MPa, tensile strength from 30.5 to values of 16.7 ÷ 32 MPa. The specific impact strength varies from 8.90 to 7.74 kJ/m2. The optimal ratio of wood and mineral fillers is 60/40%

Calculation of the viscosity of dispersions of nanoparticles with a polymer adsorption layer in a melt

As a result of theoretical analysis of the influence of the chemical structure of the polymer and the chemically modified surface of nanoparticles, it was shown that it is possible to predict the dependence of the viscosity of the polymer melt on the concentration of nanoparticles, their size, and the molecular weight of the polymer. Two situations have been analyzed where a strong intermolecular interaction between polymer chains and polar groups located on the surface of nanoparticles is absent, and when a strong intermolecular interaction between polymer chains and polar groups located on the surface of nanoparticles takes place

Selection of structural elements of cross-linked polymers used in construction

Introduction. For the first time, a model and a principle for constructing an appropriate computer program for the selection of polymer networks with a given interval of a number of physical characteristics are proposed. These characteristics include density, the temperature of the onset of intense thermal degradation, thermal conductivity, water permeability, and the stress-optical coefficient. As an example, 16 smallest base fragments are given, which, when attached to each other, allow the selection of structural fragments of repeating fragments of polymers of the following classes: polyolefins, vinyl polymers, polystyrene, polyamides, polyethers and polyesters, polycarbonates, polyetherketones, polyimides, polysulfides, polysulfones, silicone polymers, polyurethanes, cellulose derivatives, methacrylic polymers, etc. The purpose of the study is to develop a model for writing a computer program that allows the selection of structural fragments of network polymers possessing specified intervals of physical characteristics. For polymers used in the construction industry, the most important are the glass transition temperature, the stress-optical coefficient, density, water permeability, and thermal conductivity.&#x0D; &#x0D; Materials and methods. A repeating fragment of the network is selected from the smallest basic fragments, which are connected to each other using a control matrix of interactions. The matrix contains labels that allow you to control the interaction of carbon with three carbon atoms, with a carbon atom and two nitrogen atoms, with two carbon atoms and one oxygen atom, with two carbon atoms and one nitrogen atom, with four carbon atoms. There are also labels that control the interaction of carbon atoms included in the aromatic cycles with two carbon atoms and one oxygen atom, with four carbon atoms, with four nitrogen atoms, with two carbon atoms and one sulfur atom, and three oxygen atoms. This makes it possible to select a huge amount of cross-linked polymer.&#x0D; &#x0D; Results. As an example, the possible chemical structure of 14 cross-linked nodes of the polymer network is presented and the corresponding calculations are carried out, showing the adequacy of the model and the principle of constructing a computer program. The structures of the five cross-linked nodes of polymer network were used and the following physical characteristics of the resulting networks were calculated: density, the temperature of the onset of intense thermal degradation, water permeability, thermal conductivity, and the stress-optical coefficient. All these characteristics are important for the manufacture of building materials.&#x0D; &#x0D; Conclusions. The results of the work allow us to write a real computer program for the selection of repeating fragments of polymer networks that have a given interval of a number of important physical characteristics of network polymers. Among these characteristics are not only those listed above, but also other characteristics, such as glass transition temperature, Hildebrand solubility parameter, surface energy, heat capacity, intermolecular interaction energy, permittivity, etc.</jats:p