Properties Of Polymer Composite Materials Research Articles

Promoting Cross-Link Reaction of Polymers by the Matrix-Filler Interface Effect: Role of Coupling Agents and Intermediate Linkers.

The matrix-filler interface effect plays an important role in determining the structural stability and mechanical properties of polymer composite materials, which remain ambiguous and need to be studied. The network-forming dynamics of poly(3,3-bis (azidomethyl) oxetane-tetrahydrofuran) (PBT) at the ammonium perchlorate (AP) surface was studied by using atomistic molecular dynamics simulation, considering the additives of curing agent toluene diisocyanate (TDI), cross-linker trimethylolpropane (TMP), and coupling agent triethanolamine (TEA). The presence of the AP surface promotes chain cross-link reaction, which is attributed to the increased production of intermediate linkers formed by TDI, TMP, and TEA. The intermediate linker has three reactive sites that can react with PBT main chains to form a cross-linked structure. Owing to the strong interaction with the AP surface, the coupling agent TEA plays a dominant role in forming the intermediate linker. At the early stage of network forming (reaction ratio r < 30%), the AP surface adsorbs TEA, which leads to a maximum contact density to PBT. As r increases to 60%, the density of intermediate linkers near the AP surface reaches a maximum value. Consequently, the chain cross-link reactions between the intermediate linker and PBT main chains are enhanced as r > 60%. This work explains the micromechanism of the promotion of chain cross-link reaction by the interface effect and provides important insights on designing polymer materials with high mechanical properties.

Antifrictional composites based on a two-component modified phenol-formaldehyde binder

In this paper, new polymer composite materials (PCM) based on a mixture of the resole type phenol-formaldehyde and phthalide-containing phenol-formaldehyde binders, reinforced with polyoxadiazole fiber, were obtained, and their tribological properties were studied. The influence of the content of phthalide-containing phenol-formaldehyde polymer in a two-component mixture of binders on the hardness of the surface layer, tribological and thermofrictional properties of PCM in various units of dry friction on steel has been studied. It is shown that the resulting PCM are superior to PCM based on phenol-formaldehyde or phthalide-containing phenol-formaldehyde binders of the resole type in terms of tribological and thermal friction properties.

Mathematical modeling of the creation process and aging of polymer composite materials

Based on the analysis of the literature on the possibility of using neural networks to create new materials with high functional properties, the article considers a solution to the problem of determining the operational stability of polymeric composite materials by creating physical and chemically sound mathematical prediction models. Epoxy resins of the UP-637 and EA brands with an isophorone diamine hardener were chosen as the matrix of the model composite material, and oligobutadiene rubber of the SKN-10 KTR brand was chosen as the modifier. It justifies directions of work necessary for development of new materials creation methodology with optimal characteristics, building a model for changing the properties of materials at variation of composition and implementation of full-scale mathematical modeling of physical and chemical processes of polymer composite materials aging at changing level and time of climatic factors influence. Verification of the obtained dependence of service characteristics on the composition of the material and the level of influencing climatic factors was carried out on the basis of data from full-scale tests in a temperate climate. The proposed methodology for modelling the properties of polymer composite materials will reduce the development time of new materials and allow creation of polymer composites based on epoxy resin containing fillers of various natures (carbon, mineral and polymer) with high performance parameters.

Investigation of rheological properties of extruded composites based on UHMWPE

The influence of the CO-4 stabilizer on the rheological properties of polymer composite materials based on UHMWPE has been studied. It has been shown that the addition of a CO-4 stabilizer to polymer matrices significantly affects the rheological properties of materials and their extrudability. There is a change in the conformations of macromolecular chains, the absence of dependence of the viscous component on the relaxation process of the dispersed system, an increase in the complex viscosity, which led to a deterioration in the processability of the material. Based on the Han curves, it is shown that the addition of a CO-4 stabilizer leads to a deterioration in the miscibility of mixtures, i.e., the phase separation of the components of the obtained samples increases.

Polymer composite materials based on a binder from renewable raw materials: the effect of a filler on the physical and mechanical properties

Polymer composite materials have been developed using polyester-urethane-acrylate resin based on 2,5-furandicarboxylic acid obtained from plant biomass and a number of synthetic (carbon, glass, and aramid fibers) and mineral (basalt) fibrous fillers. The high operational characteristics of the obtained PCMs are demonstrated. The effect of hybridization of synthetic fibers with natural cellulose fibers (cotton) on the physical and mechanical properties of polymer composite materials has been studied. An increase in tensile strength with a simultaneous decrease in the density of PCM using a carbon fi ber/cotton hybrid filler is shown.

Прогнозирование свойств полиэтилентерефталата и композитов с углеродными нанотрубками на его основе

Molecular dynamic modeling of polymer - polyethylene terephthalate and composite materials based on it with different single- walled carbon nanotubes as filler has been performed. The influence of supramolecular structure on some physicochemical and mechanical properties of polymer composite material has been investigated. It was found that the value of interphase intermolecular interaction of the system "polymer matrix - filler" is the main determining factor influencing the physicochemical and mechanical properties, therefore, it is necessary to consider it mainly when predicting the properties of such materials.

Enhancement of Crack Resistance of Phthalonitrile-Based Carbon Fiber Reinforced Plastics by Introducing Polyamide Nonwoven Materials

The effect of introduction of polyamide nonwoven materials on the thermal and mechanical properties of polymer composite materials based on phthalonitriles and a carbon fabric is studied. It is shown that the addition of 3 wt % of polyamide nonwoven material causes a 44% increase in the specific work of delamination. At room temperature elastic mechanical characteristics, such as compressive strength and compressive modulus, for the composite modified with the nonwoven material increase by 12 and 100%, respectively. According to dynamic mechanical analysis, upon reaching 169°C the melting of polyamide occurs; however, there remains the possibility to use the composites above this temperature, as confirmed by mechanical tests performed at 200°C.

Технология изготовления образцов из полимерных композиционных материалов

The article considers the materials, composition and methods of manufacturing samples from polymer composite materials (PCM). There is presented the method of testing samples of PCM for mechanical properties. For testing, plates were made from which samples from PCM were cut, based on glass roving, glass wool and polyester resin with the addition of a hardener. Using mechanical tests, the influence of the quantitative ratio of layers of glass wool and roving fiberglass has been determined when testing samples for three-point bending, stretching and compression. A scheme of structural reinforcement of PCM plates is given, graphs of the average values of breaking loads and ultimate strengths when testing samples for three-point bending, dependences of average values of breaking loads and ultimate strengths when testing samples for tension and compression are illustrated. Comparative analysis of the average values of the tensile strength of the samples during the compression test has been carried out. As a result of processing the data obtained during the study, it was found that with an increased number of layers of roving glass in the PCM composition increases the destructive load and tensile strength, compression, but the values of the applied load of PCM samples decrease during three-point bending tests. The experimental data obtained from the test results of PCM samples are the main indicators of the mechanical properties of PCM with various reinforcement schemes for their use in ship hull structures, in particular as a material for ship tanks.

The use of microspheres to regulate the properties of polymer composite materials

Methods for regulating the properties of polymer composite materials based on epoxy, epoxy-novolac and polyurethane matrices are considered. The results of studies on the application of glass and aluminosilicate microspheres as fi llers are presented.

CURRENT STATE OF PROTECTIVE AND DECORATIVE PROPERTIES OF WATER-DISPERSION ACRYLIC COMPOSITIONS

The rapid progress of water-dispersion paints from the water-diluted group is due to a number of their advantages over other paint and varnishes from the category of environmentally friendly. The formulations of paintwork materials are dominated by aqueous dispersions of acrylic copolymers, acrylic styrole copolymers, homo- and copolymers of vinyl acetate. One of the main methods of targeted regulation of the properties of polymer composite materials and coatings is the use of surfactants (surfactants). As a result of adsorption phenomena, their physical interaction with the surface of dispersed particles and substrate, associations with film-forming molecules can significantly change the deformation-strength, insulating, adhesive, coloristic and other properties of paint coatings. The purpose of the work is a reasonable choice of polymer surfactants for obtaining water-dispersion acrylic coatings with a given set of properties. This determines the relevance of research. Objects. Film former - acrylic polymer, inorganic pigment - rutile-shaped titanium dioxide, modifying additives - polyestersiloxane copolymer (PES) and sodium polyacrylate (PAN), aqueous solvent. Conclusion. Analysis of the state and current trends in paint and varnish materials indicates the prospects of using water-dispersion acrylic compositions. The study of the physical and chemical regularities of processes involving surfactants, developed both in the volume of film-forming and at the interphase boundaries of its interface with pigment and air, is an important prerequisite for the formation of scientifically based approaches, when obtaining effective protective and decorative properties of coatings of water-dispersion compositions.

COMPOSITE MIXTURES BASED ON SYNTHETIC POLYMERS AND FILLERS AND EQUIPMENT FOR 3D PRINTING WITH THEM

The article states that the use of composite materials instead of traditional materials allows you to significantly reduce the weight of the product, while not changing the strength characteristics of this material. It was determined that polymer composite materials based on metal powders, high-strength organic (aramid) and carbon fiber fillers with a polymer matrix are promising for use as structural materials. Fillers are used to improve the operational properties of the composite material (strength, stiffness, heat resistance), give them various specific properties and reduce the cost. The classification of polymer composite materials by matrix and filler is presented. It is noted that the greatest variety of properties can be obtained using solid fillers of different nature (metals, ceramics, polymers) and structures. It has been established that both the type of filler and the shape and size of the particles are important when forming certain properties of polymer composite materials. It was determined that composite materials are used in additive technologies, in particular in 3D printing. Examples of the production of composite filaments by various companies, including various types of fillers, are given. The developed technology of printing with a mixture of polymer connector and filler using a 3D printer, which includes certain stages, is presented. Polymer materials and solid fillers of various nature were selected as the matrix for experimental research and their properties were described. The classification of equipment for forced mixing of materials is described. The developed extruder that prints with granules or composite mixtures of polymer materials and the 3D printer on which it is installed are presented. Composite mixtures for conducting experimental studies are given. The parameters of the printed samples to be examined are specified.

Identification of the parameters of a composite material by experimental-computational damping research

Calculation of the modal and damping characteristics necessary to eliminate resonant oscillation of products made of polymeric materials requires reliable data on the elastic characteristics of the material. The problem is that the mechanical properties of polymer composite materials depend on a large number of factors. The aim of the work is to determine the damping coefficients for a layered composite material and the subsequent validation of the mathematical model. The Rayleigh damping model was chosen to calculate the damping coefficients. The choice is due to the fact that the resulting stiffness and mass matrix is determined by the natural oscillation modes of the problem without attenuation, which makes it possible to split the modes into separate dynamic subtasks. A sample made according to the ASTM standard was chosen as the object of study. To increase an error of the calculation, the mathematical model of the sample was modeled in detail by the finite element method using the technique of layer-by-layer modeling. The method for determining the damping coefficients is carried out in three stages. At the first stage, with the help of modal analysis, the natural oscillation modes are determined, corresponding to the nature of the oscillation studied in the experiment. At the second stage, an implicit dynamic analysis with default damping parameters in order to calculate the damping ratio is performed. At the last stage, a steady-state dynamic analysis taking into account the characteristics obtained in the previous stages. Next, an iterative process begins, including implicit and steady-state dynamic analyses, performed alternately. At each step, the previously calculated Rayleigh proportionality coefficients are introduced into the model. As a result of the identification of the mathematical model, the damping coefficients α and β are calculated. The damping experiment was chosen as a validation problem. The damping ratio ζ was chosen as the criterion of convergence with the experimental data.

The Effect of Few-Layer Graphene on the Complex of Hardness, Strength, and Thermo Physical Properties of Polymer Composite Materials Produced by Digital Light Processing (DLP) 3D Printing.

The results of studying the effect of particles of few-layer graphene (FLG) synthesized by self-propagating high-temperature synthesis (SHS) on the complex of strength and thermo physical properties of polymer composite products obtained by digital light processing (DLP) 3D printing are presented. It was discovered to achieve an increase in thermophysical and strength parameters of polymers modified by FLG compared with samples made on the unmodified base resin. This result was achieved due to low defectiveness, namely the absence of Stone-Wales defects in the structure of FLG due to the homogeneous distribution of FLG over the volume of the polymer in the form of highly dispersed aggregates. It was possible to increase hardness by 120%, bending strength by 102%, Charpy impact strength by 205%, and thermal conductivity at 25 °C by 572% at concentrations of few-layer graphene of no more than 2 wt. %.

МОДИФИКАЦИЯ ЛИНЕЙНОГО ПОЛИЭТИЛЕНА НИЗКОЙ ПЛОТНОСТИ ЭЛЕКТРОПРОВОДНЫМ ТЕХНИЧЕСКИМ УГЛЕРОДОМ

The electrophysical and mechanical properties of polymer composite materials based on linear low-density polyethylene with the addition of electrically conductive carbon black in the range of mass concentrations of 5% ‒ 20% have been studied. A modified thermal compression technology was applied to manufacture samples from thermopolymers. An increase in the Young's modulus was revealed when filling the polymer with technical carbon by more than 2 times. The percolation threshold interval of 5% ‒ 10% is set.

Thermophysical properties of polymer composite materials based on TO-29-2 epoxy binder alloyed with AIN

Thermophysical properties of polymer composite materials based on TO-29-2 epoxy binder alloyed with AIN

Влияние ультразвуковых колебаний с наложенной низкочастотной модуляцией на механические, трибологические свойства и структуру многокомпонентного полимерного композита

One of the tasks of polymer materials science is to study the possibilities of improving the complex of elastic-strength characteristics and tribological properties of polymer composite materials by improving the manufacturing technology. In this paper, the influence of ultrasonic vibrations with a frequency of 17 kHz with a low-frequency vibration with a frequency of 100 Hz during synthesis on the properties and structure of a multicomponent polymer composite material of the KVN-3 trademark is considered. The result of the research, it is found that the influence of the technological mode of pressing, consisting in the combined effect of ultrasonic vibrations with frequency and low-frequency vibration during the synthesis of KVN-3, makes it possible to increase the complex of elastic-mechanical characteristics: tensile strength by 3 %, elongation by 6 %, modulus of elasticity by 10 %, hardness by 2 %, compared to the industrial manufacturing method, as well as to reduce the intensity of mass wear by 68 % and the coefficient of friction by 3 %. The structure of polymer composite materials after different technological pressing modes is examined. The fibrillar structure of the polymer matrix after the technological regime with the influence of ultrasonic vibrations and low-frequency modulation becomes finer and more uniform.

Enhancing the thermal conductivity of PEG composites with freeze-drying and surface treatment of MXene and CNT

To enhance the thermal properties of polymer composite materials, it is essential to appropriately configure thermal paths. Three-dimensional (3D) thermally conductive networks can serve as an excellent means for building high-speed conductive pathways in polymer composites. The MXene/acid-treated carbon nanotube/polyethylene glycol (MX/O-CNT/PEG) composite material has a 3D foam structure, and the focus is on the acid-treatment of the CNTs and foam formation of the PEG. The thermal conductivity of the synthesized composite material with 40 wt% filler loading and 3D foam was 580% higher than that of pure PEG, and it is superior to that of the composite material prepared by randomly dispersing fillers. Therefore, this work describes an advanced process to significantly improve the thermal conductivity of polymer composites.

Prospects of Applying the Neural-Network Modeling for Estimating the Structure and Properties of Polymer-Composite Materials with Hybrid Matrices

Prospects of Applying the Neural-Network Modeling for Estimating the Structure and Properties of Polymer-Composite Materials with Hybrid Matrices

Optical properties and radiation stability of polypropylene modified with MgO nanoparticles

Polymer composite materials are widely used in spacecraft and stations in thermal control coatings, as sealants, seals, thermal insulation, as well as in many other structures and products. The main characteristic of such materials is the stability of properties and performance characteristics to the action of space factors, among which various types of radiation are the main damaging ones. Therefore, it is relevant to study the influence of electron, proton, solar spectrum quanta on the change in optical, electrical, mechanical, and other properties of polymer composite materials. This paper presents the results of a investigation of the optical properties and radiation stability of nanocomposites based on polypropylene modified by the solid state method with MgO nanoparticles in the concentration range of 1–5 mass.%. Diffuse reflectance spectra were recorded in a vacuum of 2·10-6 Torr before and after electron irradiation (in situ, E = 30 keV, H = 2·1016 cm-2). The analysis of the nature of the absorption bands recorded in the diffuse reflection spectra, which are due to the formation of free radicals: – С3Н5 –, – С3Н6 –, – C4H6 –, – C4H7 –, – C4H8–, – C4H12 –, – C5H7 –, – C5H10 –, was performed. The optimal value of the concentration of nanoparticles was established, equal to 2 mass.%, at which the area of the integral absorption band at 360 nm after irradiation decreased by 3,35 times, its intensity at the maximum by 3,88 times compared with unmodified polypropylene.

Influence of Carbon Micro- and Nano-Fillers on the Viscoelastic Properties of Polyethylene Terephthalate.

In this research study, three carbon fillers of varying dimensionality in the form of graphite (3D), graphite nano-platelets (2D), and multiwall carbon nanotubes (1D) were incorporated into a matrix of poly (ethylene terephthalate), forming carbon-reinforced polymer composites. Melt compounding was followed by compression moulding and then a quenching process for some of the samples to inhibit crystallization. The samples were analysed using dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM), considering the dimensionality and loading of the carbon fillers. The dynamic mechanical analysis revealed a similar decline of storage moduli for all composites during the glassy to rubbery transition. However, storage moduli values at room temperature increased with higher loading of nano-fillers but only to a certain level; followed by a reduction attributed to the formation of agglomerates of nanotubes and/or rolled up of nano-platelets, as observed by SEM. Much greater reinforcement was observed for the carbon nanotubes compared to the graphite and or the graphite nano-platelets. The quenched PET samples showed significant changes in their dynamic mechanical properties due to both filler addition and to cold crystallization during the DMTA heating cycle. The magnitude of changes due to filler dimensionality was found to follow the order: 1D > 2D > 3D, this carbon filler with lower dimensionality have a more significant effect on the viscoelastic properties of polymer composite materials.