Polymer Composite Materials Research Articles

Welding of Parts Made of Polymer Composite Materials Based on Thermoplastics. Part 4. Test Methods and Quality Control for Welding Parts Made of Thermoplastics

Welding of Parts Made of Polymer Composite Materials Based on Thermoplastics. Part 4. Test Methods and Quality Control for Welding Parts Made of Thermoplastics

Welding of Parts Made of Polymer Composite Materials Based on Thermoplastics. Part 3. Methods for Welding Parts Made of Polymer Composite Materials Based on Thermoplastics with the Conversion of Various Types of Energy

Welding of Parts Made of Polymer Composite Materials Based on Thermoplastics. Part 3. Methods for Welding Parts Made of Polymer Composite Materials Based on Thermoplastics with the Conversion of Various Types of Energy

Study of technological aspects of manufacture of polymer composite material by centrifugal fiber forming method

The object of the study is the technological aspects of manufacturing the hesperidin polymer composite material by the method of centrifugal fiber formation. This method is considered the basis of a relatively new and cost-effective way of producing solid dispersion systems. Using the centrifugal molding method, it is possible to obtain highly soluble forms of active pharmaceutical ingredients in the form of fibers of various sizes using a wide range of polymeric materials with high speed and low cost due to simple equipment. Due to the innovative design of the centrifugal fiber formation method, it was chosen for the development of solid dispersion systems of the bioflavonoid hesperidin, which has a wide range of different pharmacological properties, but low bioavailability. Solid dispersed systems of hesperidin by the method of centrifugal fiber formation were produced on the basis of a pharmaceutically acceptable polymeric carrier of polyvinylpyrrolidone and mannitol. For the obtained solid dispersed systems, such basic pharmaco-technological characteristics as loss in mass during drying, bulk volume, bulk volume after shrinkage, bulk density, bulk density after shrinkage, compressibility index, Gaussner coefficient were determined. Comprehensive tests of the stability of the studied samples of the solid dispersion system of hesperidin were carried out under the conditions of accelerated tests for 6 months. According to the obtained results, it was established that the developed polymer composite material is stable in the studied conditions, and its conditional shelf life is 2 years. A technological scheme for the production of the hesperidin polymer composite material in the form of solid dispersed systems by the method of centrifugal fiber formation has been developed. In particular, the technological process is described step by step and the critical indicators of quality control of the obtained composite material are determined. The proposed technology can be implemented in modern chemical and pharmaceutical industries. This will contribute to the expansion of the market of highly effective socially oriented medicines.

Study on Grouting Performance Optimization of Polymer Composite Materials Applied to Water Plugging and Reinforcement in Mines.

With the increasing drilling depth of mines, the cross-complexity of fissures in the rock body, and the frequent occurrence of sudden water surges, polymer slurry, with its advantages of good permeability and strong water plugging, is increasingly used in mine grouting projects. Additional research is needed in order to further improve the grouting performance of polymer slurry, ensure the safety of mining operations, and reduce the grouting cost. In this paper, a polymer composite grouting material was prepared with diphenyl methyl diisocyanate, polyether polyol, and fly ash, as the main raw materials, with coupling agent and catalyst as auxiliary reagents. The performance of the composite grouting material in terms of mechanical properties, thermal stability, hydrophobicity, and bonding was explored. This study's findings indicated that incorporating fly ash led to notable enhancements in the thermal stability and water resistance of the polymer slurry. Furthermore, the introduction of fly ash notably raised the starting degradation temperature of the polymer, boosted the water contact angle of the composite material, and reduced the density and reaction temperature of the composite material. In addition, the catalyst and coupling agent as auxiliary reagents affected the polymers in terms of mechanical properties; in this paper, dibutyltin dilaurate was used as the catalyst, and organosilanes were used as the coupling agent. The catalyst successfully sped up the polymer's gel time, however, an excessive quantity of catalyst compromised the polymer's mechanical characteristics. The addition of organosilanes has a positive effect on the dynamic mechanical properties of the composites, fracture toughness, compression, bending, and bond strength. The research can offer a theoretical direction for creating polymer mixtures in mine grouting projects.

Role of Copper Ions in Resistance of Modern Polymer Composite Materials to Fungal Damage

Resistance of polymer composite materials to biodamage is one of the pressing problems of our time. Incorporation of Cu2O (I) in the composition of a polymer composite based on the ED-20 epoxy resin increases its biocidal properties. Under conditions of mineral and organic contamination, the area of the samples affected by micromycetes was found to decrease with increasing concentration of dispersed particles in the composite. The affected area of the samples filled with the particles encapsulated in polylactide was 1.5 times smaller than that of the composites filled with non-encapsulated particles. Сopper oxide had a toxic effect on the Aspergillus niger strain dominant on the surface of the samples, causing a decrease in the average radial growth rate on the Czapek-Dox agar medium and in the biomass weight concentration during the growth of micromycetes in a liquid medium compared to the variant without Cu2O.

Damage detection and classification of carbon fiber-reinforced polymer composite materials based on acoustic emission and convolutional recurrent neural network

Carbon fiber-reinforced polymer (CFRP) composite laminates generate acoustic emission signals during the tensile process, which can be used to identify the type of acoustic emission (AE) signal at a given moment and determine the current damage condition. However, due to the large number and complexity of AE signals generated during the tensile process of carbon fiber composite laminates, it is challenging to manually identify and annotate them. To address this issue, we propose a low-complexity classification and detection network model based on the convolutional recurrent neural network (CRNN) architecture. First, we construct a dataset of composite damage signals for a single damage category and use log-mel spectrogram features to train the model for that specific category of damage signals. Then, we utilize the trained model to recognize the AE signals of CFRP composite laminates. The proposed method achieves an accuracy of 99.02% in classifying single damage modes in the test set and effectively distinguishes the types of AE signals generated during the damage process of CFRP composite laminates. Compared with the classic classification model using AE signals, the number of parameters in our proposed low-complexity CRNN model is reduced by 94.42%. It also demonstrates that 19.4% of the AE signals during the damage process are in a superimposed state, indicating the simultaneous occurrence of multiple damage modes in CFRP composite laminates.

Toxicological Assessment of Biodegradable Poli-ε-Caprolactone Polymer Composite Materials Containing Hydroxyapatite, Bioglass, and Chitosan as Potential Biomaterials for Bone Regeneration Scaffolds.

Polycaprolactone (PCL) is a biodegradable polyester that might be used in tissue engineering to obtain scaffolds for bone reconstruction using 3D-printing technologies. New material compositions based on PCL, with improved physicochemical properties and excellent biocompatibility, would improve its applicability in bone regeneration. The aim of this study was to assess the potential toxic effects of PCL-based composite materials containing 5% hydroxyapatite (PCL/SHAP), 5% bioglass (PCL/BIO), or 5% chitosan (PCL/CH) on MG-63 human fibroblast-like cells in vitro. Material tests were carried out using X-ray diffraction, differential thermal analysis/thermal gravimetry, BET specific surface analysis, and scanning electron microscopy. The effect of the biomaterials on the MG-63 cells was then assessed based on toxicity tests using indirect and direct contact methods. The analysis showed that the tested biomaterials did not significantly affect cell morphology, viability, proliferation, or migration. We concluded that biodegradable PCL-based scaffolds may be suitable for tissue scaffold production, and the addition of bioglass improves the growth of cultured cells.

Structural features of nickel clad carbon fibers and determination of their thermophysical properties using pulsed radiation

It was considered the forming multilayer heat-resistant coatings that work under conditions of elevated temperatures and long-term oxidation. The issue of increasing the service life of the parts by strengthening their bulk and surface is considered. The issue of determining the level of the thermophysical properties is also considered. The thermophysical properties of carbonyl iron reinforced with carbon fibers (CF) pre-clad with nickel are investigated. Unclad and nickel clad carbon fibers were produced. The thermal conductivities of the samples are determined depending on the conditions of their production. The thermal conductivity characteristics of polymer composite materials based on CF with ceramic hollow microspheres and carbonyl iron from CF depending on the conditions of their production were determined. It is shown that heat transfer mechanisms related to the electron-lattice interaction can function in these systems. Heat transfer can occur by various transport mechanisms, such as collisions or diffusion. Nevertheless, the increase in thermal conductivity can be related to the electronic mechanism. The thermal conductivity of materials based on carbonyl iron with nickel-plated CF is 1.2 times higher compared to unclad CF, which is due to better adhesive interaction between the coated carbon fibers and iron was established.

Design optimization of lightweight automotive seatback through additive manufacturing compression overmolding of metal polymer composites

With the growing demand for enhanced automotive fuel efficiency and environmental sustainability, there is a need for lightweighting automotive components through innovative design and manufacturing processes. This study leverages a combination of numerical iterative design optimization and hybrid additive manufacturing–compression molding (AM-CM) technique for metal polymer composites to lightweight an automotive seatback. The AM-CM process enables robust mechanical interlocking between metals and composites, boasting high stiffness and strength with low overall density. Replacing metallic components with such metal polymer composites allows for comparable mechanical performance while significantly reducing the overall weight. First, the automotive seatback design space is reduced to critical load carrying regions using topology optimization and high stress concentration areas are identified using finite element analysis. Next, a lightweight metal polymer subcomponent is designed for a high stress concentration region. The full seatback frame with spatially heterogeneous material-specific design is then iteratively optimized to enable enhanced stiffness with minimal weight. Overall, the automotive seatback frame designed with location-specific metal, polymer, and metal polymer composite materials weighs 20% less than the metal-only design while exhibiting similar stiffness.

Effect of alkali treatment on new lignocellulosic fibres from the stem of the Aster squamatus plant

This research aims to examine the physical, structural and chemical properties of Aster Squamatus (AS) fibres, which are commonly found in Algeria, Brazil, France and the West Indies. In this work, we assess their appropriateness as reinforcing fillers to fabricate components for polymer composites principally designed for lightweight applications. To accomplish this objective, an extraction of fibres from plants modification of AS fibres and characterization of both untreated fibres (UASFs) and alkali-treated AS fibres (TASFs) are conducted. We analysed the crystallinity, chemical composition, thermal characteristics, and mechanical properties of AS fibres as per standard methods. It's clear from chemical treatment that amorphous components were successfully eliminated from the AS fibres, including hemicellulose, lignin, and wax. Consequently, the fibres' thermal, physical, and mechanical characteristics including Young's modulus, tensile strength, crystalline index, and surface roughness were substantially enhanced. It was determined that the fibres possessed a thermal stability of around 250 °C, with the maximal degradation temperature rising from 372.50 to 375.35 °C. The maximum stress rose from 183.24 ± 25.27 to 302.00 ± 24.91 MPa, the Young's modulus increased from 11.08 ± 1.1 to 18.53 ± 1.45 GPa, and the crystallinity index increased from 43% to 45%. Two-parameter Weibull statistics showed a strong link between experimental data and mechanical features of the twenty samples. We concluded from this work that AS plant fibres can serve as a robust reinforcing material in polymer composites for various applications.

Structural effects on heat capacity, moisture absorption and thermal expansion of epoxy-novolac polymers

Today epoxy novolac resins are of great interest for the aerospace industry. Thermal properties of the polymer matrix, as well as the effect of moisture on the characteristics of polymer composite materials (PCM) under thermomechanical impacts, are critical tasks in creating dimensionally stable structures operating in a wide temperature range. Particularly, thermal and moisture expansion as well as heat capacity are important parameters for evaluating of polymer matrices and modeling their properties. In this work, polymers based on a number of epoxy novolac resins with aromatic amine hardener were studied. The values of the crosslink density were experimentally determined, and a comparative analysis of thermal expansion and heat capacity for epoxy polymers with different crosslink density was carried out. The dependence of thermophysical properties on polymer crosslinking density is shown, both in glass and highly elastic states. Additionally, this study analyzes the process of water sorption by polymers and the coefficient of moisture expansion. The most significant dependence of the diffusion coefficient was observed with coefficient of moisture expansion.

Recent Developments of Pineapple Leaf Fiber (PALF) Utilization in the Polymer Composites—A Review

Plant fibers’ wide availability and accessibility are the main causes of the growing interest in sustainable technologies. The two primary factors to consider while concentrating on composite materials are their low weight and highly specific features, as well as their environmental friendliness. Pineapple leaf fiber (PALF) stands out among natural fibers due to its rich cellulose content, cost-effectiveness, eco-friendliness, and good fiber strength. This review provides an intensive assessment of the surface treatment, extraction, characterization, modifications and progress, mechanical properties, and potential applications of PALF-based polymer composites. Classification of natural fibers, synthetic fibers, chemical composition, micro cellulose, nanocellulose, and cellulose-based polymer composite applications have been extensively reviewed and reported. Besides, the reviewed PALF can be extracted into natural fiber cellulose and lignin can be used as reinforcement for the development of polymer biocomposites with desirable properties. Furthermore, this review article is keen to study the biodegradation of natural fibers, lignocellulosic biopolymers, and biocomposites in soil and ocean environments. Through an evaluation of the existing literature, this review provides a detailed summary of PALF-based polymer composite material as suitable for various industrial applications, including energy generation, storage, conversion, and mulching films.

Enhancement of flame retardancy in ceramic polymer composite materials with ammonium polyphosphate/melamine cyanurate

AbstractTo enhance the flame‐retardant characteristics of ceramifiable polyethylene (PE) composites, a composite flame retardant comprising ammonium polyphosphate (APP) and melamine cyanurate (MCA) was integrated. This addition markedly bolstered their flame‐retardant attributes. A meticulous exploration was conducted to ascertain the impacts of APP and MCA on the ceramifiable PE composites' visible morphology, mechanical robustness, and dimensional constancy, and to study the phase transition and microstructure deformation during sintering. Findings underscored that the amalgamation of APP/MCA markedly enhanced the flame resistance of these ceramifiable composites, registering a limiting oxygen index of 25.6% and achieving the vertical burning test (UL‐94) rating of V‐0. The collaborative flame‐retardant action of APP/MCA significantly enhanced the flame resistance of the PE composites while effectively mitigating the composite's propensity to drip. Upon detailed phase analysis, a eutectic reaction was observed between APP and wollastonite fiber, culminating in the genesis of a novel crystalline phase, calcium pyrophosphate (Ca2P2O7). When subjected to elevated temperatures, glass–ceramics manifest with both crystalline and vitreous phases. The proportion of the vitreous phase plays a pivotal role in influencing the ceramic's overall performance.

Local Energy of Activation of Conductivity of Phenylene-Based Composite Materials Containing Nickel Nanoparticles

By measuring the dependence of conductivity on temperature and analyzing this dependence within the framework of the reduced conductivity activation energy, it was found that in composite polymer materials containing Nickel nanoparticles in the region below the classical percolation threshold in the studied temperature range, there are three regions with different temperature dependence. The origin of these dependencies is discussed in terms of a spatial-structural hierarchical model.

Wood flour / ceramic reinforced Polylactic Acid based 3D - printed functionally grade structural material for integrated engineering applications: A numerical and experimental characteristic investigation

Recently, efforts have been done to capitalize on the potential of multidisciplinary research in order to produce unique features in polymer technology. To improve its physical and chemical properties for any intended use, the most promising Polylactic acid (PLA) has recently been copolymerized using other polymeric or non-polymeric components. This investigation aims to employ the material extrusion (MEX) process to develop a new functionally grade structural material (FGSM) by alternate layer deposition of wood flour reinforced PLA (WPLA) and ceramic reinforced PLA (CPLA). The mechanical properties of the printed laminates are examined using tensile, compression and three point bend tests. The microscopic investigation is used to assess fracture morphologies. A numerical simulation is also performed using ABAQUS under standardized parametric settings to investigate the mechanical behaviour of the laminates. The experimental and numerical results are consistent, with a deviation about ∼1 %. The tensile, compressive, and flexural strength of the newly developed FGSM are 61.39, 95.4, and 107.8 % higher than those of WPLA printed laminates. Furthermore, the acquired mechanical behaviour results are merely comparable to those of CPLA printed laminates. DSC thermograms demonstrate that FGSM has a better glass transition temperature (66oC) and a cold crystalline temperature (87.63oC), which contributes to its thermal stability. Overall, the newly developed FGSM might be considered a viable alternative, mechanically strong, and less expensive polymer composite material for structural built applications in any engineering and related fields.

Composites from Recycled Polypropylene and Carboxymethylcellulose with Potential Uses in the Interior Design of Vehicles.

This research investigates novel polymeric composite materials for automotive interior trim applications. The composites utilize recycled polypropylene (PPr) matrix and carboxymethylcellulose (CMC) as filler (PPr/CMC: 100/0, 95/5, and 90/10 wt.%). The materials were processed by extrusion and injection molding. Considering their intended application, the composites were evaluated for resistance to key climatic factors, i.e., temperature, humidity, and UV radiation. In addition, structural analyses and FTIR analyses were performed to assess potential heterogeneity and thermal stability. Following FTIR tests, the incorporation of carboxymethyl cellulose in polypropylene is confirmed by the detection of characteristic CMC bands for -OH, C=O, and C-O-C groups. The results indicate slight structural heterogeneity in the 5% and 10% CMC composites. However, no thermal distortions were observed in either the composites or the PPr matrix itself. The behavior of PPr/CMC composites under the action of the mentioned climatic factors has been assessed from the variation of dielectric characteristics with frequency. The strong polarization of CMC leads to a sharp increase in composites electrical conductivity after submersion in water for 480 h, suggesting weakening of the composite structure. After exposure to UV radiation, a sharp increase in conductivity is observed even after the first cycle (72 h) of UV radiation. Following the experimental results obtained in our study, it is recommended to use the PPr +10% CMC composite for obtaining different interior ornaments (carpets, supports, etc.). At the same time, the use of these materials also has the advantage of lightening the mass of the vehicle due to their lower density than polymers.

Development and characterization of hybrid polymer composite materials with reinforcement of glass/carbon fibers for enhanced mechanical properties: an experimental and numerical approach

Composite materials, particularly fiber-reinforced plastics (FRP), are used in aerospace and automotive industries due to their desirable properties and surpassing traditional metals in various applications. Researchers are countering the drawbacks of using a single fiber type in FRP by creating hybrid composites that combine different fibers in a single matrix. These hybrids harness the cost-effectiveness and corrosion resistance of glass fibers alongside the strength and stiffness of carbon fibers, resulting in a balanced combination of properties for various applications. Tensile tests were performed according to the ASTM D3039 standard, with a 2 mm/min strain rate. The results showed that increasing the carbon fiber percentage (6.56%, 13.79%, and 21.07%) led to significant improvements in the tensile strength of the hybrid composites (34.18%, 55.44%, and 85.40% higher than glass fiber composites). However, changing the stacking sequence did not significantly affect tensile strength, indicating its insignificance in this regard. Numerical simulations were conducted to validate the experimental results, and the errors between experimental and numerical data were below 10% for various stacking sequences. These discrepancies were attributed to factors such as fiber waviness, which resulted in heterogeneous property distribution within the composites, and the manufacturing process used for creating the hybrid composites. Scanning electron microscope analysis was also performed to study the failure modes on the fracture surface of the tensile-tested specimens.

Study of the microstructure of asphalt concrete using X-ray computed tomography

A mechanical digital twin (a mechanical finite-element model) of an asphalt concrete sample has been developed in the framework of a project for recycling polymer composite materials with fibrous reinforcement (fiberglass) as an alternative for crushed stone in the asphalt concrete production. A methodology of using X-ray computed tomography (XCT) for analysis of the asphalt concrete microstructure and calculation of the mechanical properties is developed. The data processing chain for developing a digital twin of the asphalt concrete microstructure, based on X-ray micro-computed tomography (XCT) image includes the following steps: 1) image enhancement; 2) image segmentation; 3) analysis of the morphology of pores and solid particles; 4) transformation of the segmented image into a voxels-based finite element (FE) model. It is demonstrated that the XCT resolution of 40 μm is sufficient for a reliable identification of microstructural parameters, i.e., volume fractions of the components, distributions of voids (pores) in size, shape and spatial position, as well as distributions of the crushed brittle additives (fiberglass chips) in size. The FE model constitutes a digital twin of the material, and, after specifying the characteristics of the material components, can be used for simulation of the thermomechanical and functional properties of the material. The developed procedure is exemplified in the calculation of statistics of the compression and shear moduli of the asphalt concrete with addition of crushed fiberglass particles. The dependence of the calculated elastic properties on the size of the digital twin is studied. It is shown that a model size of 10 mm and more is sufficient for the microstructural representativity and calculation of the homogenization characteristics. The results can be used for analysis of the microstructure and structure-dependent thermomechanical properties of asphalt concrete. The developed finite element model can be used for modelling of the visco-elastic response of asphalt concrete and its behavior under cyclic loading.

An Investigation of the Energy-Absorption Characteristics of Thin-Walled Polymer Composite C-Channels: Experiment and Stacked Shell Simulation.

Polymer composite materials are increasingly used in civil aircraft structures. The failure mode and energy-absorption characteristics of polymer composite structures have garnered significant attention from academia and industry. For thin-walled polymer composite C-channels with layups of [0/90]3s, [45/-45]3s, and [45/90/-45/0]3, low-speed axial compression tests were performed to investigate the failure modes, failure mechanisms, and energy-absorbing characteristics. After parametric studies using [0] and [90] single-element models, stacked shell models of thin-walled composite C-channels were established using the Lavadèze single-layer damage constitutive model, Puck 2000, and Yamada Sun failure criteria. The results show that these thin-walled composite C-channels exhibit a stable progressive crushing process with a local buckling failure mode, encompassing local buckling, fiber break-age, matrix cracks, delamination, and corner cracking. The stacked shell model demonstrates reasonable agreement with the progressive crushing process of thin-walled composites, accurately capturing interlayer matrix failure and interface delamination cracking behavior. A comparison of the specific energy absorption (SEA) and mean crushing force (Fmean) between the simulation and test results yields a difference of less than 6%, indicating a strong correlation between the simulation results and the experimental energy-absorbing characteristics. It also shows that a deep understanding of the parameters is helpful for accurate numerical modeling.

Interfacial strength and its regulation in the carbon monofiber/epoxy binder system

The strength of polymer composite materials (CMs) is largely determined by the strength of interfacial interactions at a fiber/matrix interface. In this work the strength in a unit cell of CM carbon monofiber/cured epoxy matrix is investigated. The relevance of the work is due to direct measurements of strength at the monofiber/matrix interface, excluding defects of micro-droplet and technological errors associated with impregnation in a traditional assessment of polymer composite materials strength. Changes of surface morphology and energy characteristics of fibers in plasma chemical treatment process is shown. The study of fiber surface energy and formation of carbon monofiber/epoxy matrix interface of carbon fiber reinforced composite unit cell was carried out on the specially developed original device Drop-Sting test. Micro pull-out test was used to investigate the shear mechanical properties of interface and to determine the strength of carbon fiber reinforced composite unit cells before and after treatment in oxygen discharge plasma. It is shown that the increase in the strength of the monofiber/matrix interfacial interface after the treatment of carbon fiber in plasma occurs due to the increase in the surface energy and wettability of monofibers.