Polymer Composite Materials Research Articles

Influence of modifying additives on the structure and properties of biodegradable mixtures based on poly-3-hydroxybutyrate and nitrile butadiene rubber

Objectives. To investigate polymer composite materials based on poly-3-hydroxybutyrate (PHB) of microbiological origin and the synthetic nitrile butadiene rubber NBR-28. The biodegradability of PHB implies the possibility of its use for invasive medical purposes; however, this is significantly limited by its brittleness. The aim of this work was to search for approaches to altering the molecular structure of PHB-based composites, in order to impart them with sufficient physical and mechanical characteristics and increase their compatibility without violating biodegradability.Methods. Reaction mixtures contained the elastic material NBR-28, various modifiers (sorbitan oleate, epoxidized soybean oil, siloxane rubber), and additional polymer components (ethylene–vinyl acetate copolymer and polybutylene adipate terephthalate). The mixtures were prepared in a PL 2200-3 plasticorder (Brabender, Russia) by pressing, holding the material at 180°C under pressure for 3 min followed by quenching in cold water. The surfaces of the films and plates of the mixtures were studied using an Axio Imager Z2m optical microscope (Carl Zeiss, Germany) with the Axio Vision software at 50× and 200× magnification in reflected light. The mechanical properties of materials under tension were measured using an Instron 3365 universal tensile testing machine (Instron, United Kingdom).Results. The role of modifiers and polymer additives in the PHB–NBR-28 composites and their influence on the morphology of mixtures, crystallinity, and mechanical characteristics were established. The introduction of modifiers made it possible to reduce the average particle size of the NBR-28 phase in the PHB matrix by 30–50%, additionally changing their morphology. In this case, the uniformity of particle distribution increased, having a positive effect on the mechanical characteristics of the systems.Conclusions. It was shown that the modifiers change the morphology of mixtures, reduce the average particle size of the NBR phase by 30–50%, and positively affect the strength of the systems. Owing to changes in the structure of their interfacial layers and, as a consequence, physical and mechanical characteristics, the resulting composites render suitable for use in reparative bone and dental surgery, as well as for creating wound healing materials.

Universal Construction of Electrical Insulation and High-Thermal-Conductivity Composites Based on the In Situ Exfoliation of Boron Nitride-Graphene Hybrid Filler.

Hexagonal boron nitride (h-BN), with excellent thermal conductivity and insulation capability, has garnered significant attention in the field of electronic thermal management. However, the thermal conductivity of the h-BN-enhanced polymer composite material is far from that expected because of the insurmountable interfacial thermal resistance. In order to realize the high thermal conductivity of polymer composite thermal interface materials, herein, an in situ exfoliation method has been employed to prepare a boron nitride nanosheet-graphene (BNNS-Gr) hybrid filler. After being incorporated into a poly(ethylene glycol) (PEG) matrix, the thermal conductivity of composites is significantly improved on the premise of electrical insulation. Furthermore, a three-dimensional (3D) thermally conductive framework using this hybrid filler as the raw material has also been constructed. After incorporating poly(ethylene glycol) (PEG) through a vacuum impregnation method, this ordered structure effectively resolves the leakage issue in phase-change composites during actual working conditions and showcases enhanced thermal conductivity of 2.45 W m-1 K-1 at 10 vol %, along with excellent electrical insulation, shape stability, and cyclic stability. The modified Hashin-Shtrikman model and the Foygel nonlinear model prove that compounding graphene with BN reduces the interfacial thermal resistance of polymer composites for both disordered and ordered systems. This indicates that the in situ exfoliation strategy is an effective method to fabricate the nanofiller for reducing the interfacial thermal resistance of composites.

The Influence of the Wood Essence of Beams Reinforced with Polymer Composite Materials on the Mechanical Properties

Wooden resistance elements, such as beams and pillars, are often used in construction. They must be designed and made so as to withstand the loads to which they are subjected during use. The predominant stress of the beams is bending, the maximum values of normal stresses due to the loads that solicitate the beams being important to know for ensuring its bearing capacity. In this paper an experimental study is presented regarding the resistance elements of the beams type. The beams are made of two types of wood, namely beech wood and poplar wood, having a rectangular section. These beams were reinforced with composite materials based on carbon fiber such as plates and fabric that were applied to the beams with the help of an epoxy resin, in order to study their behavior when subjected to bending stress. Bending tests were made until the beams were damaged, measuring, in this sense, the applied forces and the related displacements. The strength of wooden beams reinforced with composite materials was compared with the strength of wooden beams without the addition of composite material, thus establishing which is the better constructive reinforcement solution, for the two essences of wood, to ensure safety in operation, in construction field.

Bioinspired Antiwear Poly(urea-imide) Composites: Influence of Tribology on Polymer Crystal Structure.

Polymer composite materials encounter considerable challenges in sustaining superior tribological properties at high rotational speeds. Inspired by the microstructure of dragonfly wings, a novel thermally stable and ambient pressure curing poly(urea-imide) resin (PURI) with excellent tribological properties has been eco-friendly synthesis using bio-based greener solvents. Furthermore, The PURI composites enhanced with polyether ether ketone (PEEK) and Polytetrafluoroethylene (PTFE) blended fabrics demonstrate excellent mechanical, with tensile strengths exceeding 175MPa. The PURI composites synthesized in the green solvent dimethyl isosorbide (DMI) exhibit an average friction coefficient of 0.1160 and an average wear rate of 2.7×10-14m3(N·m)-1 at 800rmin-1. The excellent tribological performance is primarily attributed to the molecular chain rearrangement of the PURI resin during friction, which leads to the formation of crystalline structures in certain regions, a phenomenon known as friction-induced crystallization. This process is an entropy-reducing mechanism that absorbs other forms of energy, such as frictional heat, during the frictional process. Moreover, the PTFE fibers underwent tribochemical reactions resulting in changes to lattice spacing during friction and contributing to the formation of the tribofilm. This study provides new evidence regarding the frictional mechanisms of polymer composites, which is beneficial for designing high-performance wear-resistant composites.

Hygrothermal ageing effects on failure behaviour of fibre-reinforced polymer composite materials under in-situ SEM testing

Hygrothermal ageing effects on failure behaviour of fibre-reinforced polymer composite materials under in-situ SEM testing

Experimental analysis of polymer-composite coated steel components under quasi-static loading

In recent years, there has been new interest in understanding the mechanical failures of the polymer-composites used for fairing the hull and the superstructure of large vessels. There aren’t any background studies looking into the failures of these thick coated structures and this study is attempting to bridge the gap in research by studying the monotonic flexural behaviour of these structures to investigate the reasons for its failures. The objective is to study the monotonic flexural behaviour of three popular particulate composite materials used as coatings on megayacht vessels and obtain an initial understanding of their behaviour and interaction with the steel substrate. The methods presented are both analytical and standard testing procedures for the examination of the flexural stress-strain response of the thick polymer-composite coated steel specimens. The results of this work suggest that different failure mechanisms have been observed in the three examined coating systems. It has been shown that the experimental data suggested no significant interaction between the steel and the polymer-composite material. The findings suggest that it is possible to enlarge the design space of the polymer-composite coatings by reducing the applied thickness of the materials. Results also have shown that the presence of voids cause reduction in strength by 20% and reduction in deformation by 30%. The study concluded to a two-step methodology involving analytical and experimental methods investigating the mechanical response of composite polymers applied on hull and superstructure substrates which is presented for the first time in this paper.

Mechanical, thermal and morphological analysis of polylactic acid‐woven glass fiber composites fabricated by additive manufacturing

AbstractPolylactic acid (PLA), a biodegradable thermoplastic, is being used significantly in a wide range of applications because of its environmentally friendly nature. 3D printing is an innovative technique that is used to fabricate polymer composites with complex contours and high precision. Conventional 3D printing technologies use fiber reinforcement in the form of filament. However, fibers in the form of sheets, when used in composite materials, improve the distribution of load and enhance the multi‐directional strength. This study investigates the improvement in the tensile strength of PLA‐based composite by integrating woven glass fibers (WGF) during 3D printing processing. The composites were fabricated using an FDM‐based 3D printer where the WGF sheet was used as reinforcement and PLA filament was used as the matrix material. The main input parameters consist of the number of WGF layers and the orientation of the WGF. Taguchi orthogonal array was used to fabricate composite samples with different combinations of input parameters and then these samples were tested to evaluate the tensile properties. The finding shows that PLA composites reinforced with four layers of glass fiber at 0/90° fiber orientation showed the highest tensile strength of 52.85 MPa and a thermal degradation temperature of 330.49 °C.Highlights 3D printing of WGF‐PLA composite and mechanical characterization. The composite specimen showed the highest tensile strength of 52.85 MPa. The thermal degradation temperature reached 330.49 °C in TGA analysis. ANN predicted the optimal combination of 4 fiber layers with 0/90° orientation. Uniform PLA deposition reduced voids and enhanced interlayer adhesion.

Determination of influence factores and stress concentration factor for express strength calculations of single-cut bolted connections of layered composite plates. Message 1

When designing bolted joints (BJ), it is necessary, in particular, to carry out their verification calculations for strength. At the same time, it is desirable to use express analysis: calculations by simple formulas of sufficient accuracy. For BJ of plates made of layered polymer composite materials (PCM), the problem has not been solved yet. Objective. To revise, to rethink and structure the formulas for the express calculation of the maximum stress when the hole is in contact with a rigid cylinder (bolt). Carry out a review on contrasting examples of materials and schemes of PCM plate reinforcement, taking into account possible lateral bolt/hole clearances in a practically relevant range, based on previously obtained and new results. Numerical calculations were carried out using the finite element method (contact problem) for the BJ plate made of laminated PCM. 3D orthotropy of each monolayer was assumed. Several simple express analysis formulas were checked, and their structuring was carried out. The results are summarized in a table, illustrations are given. Five factores influencing the value of the maximum tensile stress near the hole in the laminated PCM plate are separated. Numerical estimates were obtained that characterize the degree of influence on the stress concentration on the surface of the hole: material characteristics, reinforcement scheme, and bolt/hole gap sizes in the laminated PCM plate, as well as the accuracy of the considered formulas. A change in the material and scheme of reinforcement of the layered PCM leads to a significant change in the values ​​of the maximum stresses and stress concentration factor (SCF) in the bolt-loaded hole in the cross-section of the plate weakened by the hole. The considered express analysis formulas have insufficient accuracy for contrasting cases of materials and plate reinforcement schemes. Additional research is needed, especially for the reinforcement scheme [φ/-φ]2s at 0<φ<90.

Stress-strain properties of microwave-irradiated polymer composite based on PDI-3A rubber

The stress diagram of polymer composite material based on PDI-3A rubber filled with thermally expanded graphite or potassium chloride before and after microwave treatment for 300, 600, 900 and 1200 s has been studied. A twofold increase in tensile strength and deformability was found after microwave treatment for 300 c and testing at 223 K. With increasing the test temperature or microwave treatment time, a marked decrease in the deformation and tensile strength characteristics of the obtained composites was observed.

PERFORMANCE-BASED SEISMIC RETROFIT DESIGN FOR RC FRAMES USING FRP COMPOSITE MATERIALS

Seismic retrofitting of reinforced concrete (RC) members using fiber reinforced polymer (FRP) composite materials has become a well-established technique for repairing and strengthening seismically deficient systems. Although there has been significant progress on behavioral modeling of FRP retrofitted RC members as well as on implementation of performance-based analysis and design concepts, the studies investigating the overall seismic behavior of the retrofitted frames are still limited. This paper presents a methodology for performance-based FRP retrofit design for RC frames and provides an analytical investigation of this through numerical studies performed on 2-D frame models with different retrofit configurations. More specifically, frame systems with square or rectangular columns were assumed to be retrofitted through FRP strengthening of beams for improved flexural capacity and/or wrapping of columns for additional confinement and resulting ductility. Nonlinear pushover analyses of frames before and after retrofitting were performed using nonlinear hinge parameters determined from moment-curvature analyses based on comparative use of various steel- and FRP-confined concrete models proposed in the literature. Analysis results reveal the expected contribution of each retrofit configuration to the seismic behavior and performance of the frames, highlighting various design considerations for proper FRP retrofit decisions.

Novel methods to determine hydrothermal residual stresses in fibre reinforced polymer composite materials

Novel methods to determine hydrothermal residual stresses in fibre reinforced polymer composite materials

Review on Superhydrophobic Polymer Composite Coating Materials and its Coating Technology for Advanced Applications

ABSTRACT Researchers all over the world are working to produce improved polymeric materials suitable for cutting-edge advanced applications that will eventually replace traditional materials. Polymeric materials that display super hydrophobic characteristics are quite valuable and interesting when it comes to the development of things with lotus leaf surface effects. In recent decades, super hydrophobic surfaces (SHS) have been considered as key parameter, and superhydrophobic coatings are vital to achieve materials with hydrophobic surface. The most crucial criteria influencing super hydrophobic surfaces are low surface free energy and higher surface roughness. Explorations on superhydrophobic surfaces (SHS) are very interesting because of their importance in varied nature of industrial, engineering and bio-medical applications. Superhydrophobic membranes have made a lot of curiosity recently, especially for efficient oil-water separation application. A major exploitation of these SHS is to increase the corrosion resistance of surfaces exposed to corrosive environments as well as their long-term chemical stability and maintaining the superhydrophobic characteristics. The other major important sectors utilize these materials to achieve ultra-superhydrophobic behavior are space and aerospace, defense, automotive, marine, water-oil separation, biomedical-engineering, and sensors. Superhydrophobic surfaces repel water primarily due to their surface texture and physicochemical properties. The present article deals with the basic and fundamental principles, importance and applications of superhydrophobic behavior of materials, including different analytical and fabrication techniques used to study and to ascertain the super hydrophobic properties of the materials.

Examining the impact of anisotropic particle orientation in a polymer matrix on the electrical properties of composite materials

A number of works have experimentally shown the significant influence of mechanical stretching on the electrically conductive properties of composite polymer materials. Thus, stretching polymer composite films and filaments can lead to deterioration in electrical conductivity properties which can significantly affect the characteristics of products made from such materials. The research conducted in this study focuses on simulation the impact of anisotropic particle orientation within a polymer matrix and mechanical stretching on the electrical properties of composite materials. Based on the Boltzmann statistics, an expression was obtained that allows predicting the change in electrical conductivity during the stretching of polymer composite samples. The Monte Carlo method was used to simulate the destruction of a percolation chain of conductive particles during stretching.

The Effect of Textile Structure Reinforcement on Polymer Composite Material Mechanical Behavior.

Investigating the impact of textile structure reinforcement on the mechanical characteristics of polymer composites produced by the compression molding technique was the goal of this work. An epoxy resin system served as the matrix, and various woven (plain, twill, basket), nonwoven (mat), and unidirectional (UD) textile structures made from E-glass fibers were employed as reinforcement elements. Compression molding of pre-impregnated textile materials (prepregs) was used to create the composites. The well-impregnated textile structures with resin into prepreg and the good interface between layers of the composites were verified during the manufacture of the polymer-textile composites using DSC thermal analysis and an SEM microscope. For the mechanical behavior, flexural properties were determined. The composite samples with unidirectional prepreg reinforcement have the highest longitudinal flexural strengths at roughly 900 MPa. The woven prepreg-based composite laminates show balanced flexural properties in both directions. Composites based on plane and basket prepregs have a flexural strength of about 450 MPa. Their flexural strength is over 20% lower than that of the samples made using twill prepreg. In both directions, nonwoven prepreg-reinforced composite samples show the least amount of resistance to bending stresses (flexural strength of roughly 150 MPa).

Fabrication and Characterization of Acetic Acid-Treated Salago Fiber–Epoxy Composite: Enhancing Mechanical and Thermal Properties

In this paper, an experimental investigation of the effect of acetic acid treatment on the mechanical, thermal, and morphological properties of salago fiber composites is conducted. Salago fibers are natural fibers derived from a shrub native to the Philippines and other tropical countries. They have potential applications in the manufacturing industry as reinforcement materials for polymer composites, owing to their low cost, environmental friendliness, and lightweight. However, they also have some limitations, such as poor adhesion to the matrix and low resistance to biological degradation. To address these challenges, the salago fibers were pretreated with four different concentrations of acetic acid solution (0%, 5%, 10%, and 15%) and then neutralized with sodium hydroxide. The treated fibers were then combined with epoxy resin and fabricated into composite specimens. The specimens were tested for their tensile, flexural, impact, and thermal properties. The morphology and fracture behavior of the specimens were also examined using scanning electron microscopy. The results indicated that the optimal concentration of acetic acid treatment was 5%, which enhanced the fiber-matrix interface and improved the strength, stiffness, and thermal stability of the composite. The 5% acetic acid-treated fiber composites also exhibited better performance than the untreated fiber composites. The paper concludes that acetic acid treatment is a promising technique to improve the properties of salago fiber composites for various industrial applications.

Green Composites in Aviation: Optimizing Natural Fiber and Polymer Selection for Sustainable Aircraft Cabin Materials

The increasing demands on global resources due to technological development driven by consumer expectations and demands have resulted in significant problems with ecological sustainability and material availability. The creation of biocomposites has resulted in notable advancements in the green industry within the materials science area this century, owing to concerns regarding sustainability and the environment. Globally, there is a surge in the creation of highly efficient materials derived from natural resources. In aviation applications, plant fiber-supported polymer composite materials are becoming increasingly popular. Aerospace materials are typically used in aircraft construction as structural materials to support loads throughout different flight phases. There are many diverse mechanical qualities of natural fibers; therefore, selecting one for the interior parts of an aircraft cabin based only on its attributes leads to a multiple-attribute decision-support issue. In this paper, the effective natural fiber and polymer choice for use as reinforcing materials in composite materials is represented as the composite materials’ improvement to aircraft cabin luggage for aerospace implementations. This study can guide material designers in investigating different hybrid materials with the most effective natural fiber and polymer obtained by hierarchical strategy by elucidating the effective material choice to meet the criteria determined for the aircraft cabin luggage. For this purpose, the definitive rankings of the twelve polymers and sixteen natural fibers in terms of performance score were assessed using a hierarchical strategy methodology.

ФОРМОУТВОРЕННЯ НАМОТУВАННЯМ КОМПОЗИТНОГО ПЕРЕДНЬОГО ГОРИЗОНТАЛЬНОГО ОПЕРЕННЯ ЛЕГКОГО ЛІТАКА

A process has been developed for modeling the trajectory of laying reinforcing material (RM) during the formation of composite aerodynamic surfaces (AS). The work provides a brief description of the types of structures of aircraft of complex shape according to the criterion of the possibility of manufacturing by the winding method, in which certain types of surface shapes are highlighted according to the condition of determining the laying trajectory and developing a winding control program (WCP) for CNC machines. It is shown that the process of developing technology for manufacturing structures such as aerodynamic load-bearing surfaces has significant differences from the process of developing technology for axisymmetric products. The general technique for determining the trajectory of laying reinforcing material is shown and new approaches to specifying the reinforcement pattern are described. The general methodology for calculating the WCP for winding the AS is described. Calculation of the movements of the working parts of a winding machine (WM) includes several subtasks: choosing the order of passage of individual turns of the RM, calculating the movements of the working parts of the WM when laying each turn, and determining the program for transition from turn to turn. It is shown that the most important stage in the development of general-type AS winding technology is the choice of a winding scheme that determines the structural-force diagram (SFD) of the structure. For this purpose, the concept of the limiting point of winding has been introduced. The winding pattern of any type of product can be described by an array of coordinates of boundary points and reinforcement angles. An algorithm for calculating the trajectory of RM placement on the surface of the mandrel is presented. The features of choosing the order of passage of turns are described. The order in which the turns pass affects the number of weaves in the structure of the composite material obtained during the winding process and the strength of the product. The optimal order of passing turns according to the strength criterion is determined experimentally through repeated development tests. The features of choosing programs for transition from turn to turn are described. The algorithm of actions of the WM during the transition from one turn to another - the transition program consists of two programs: the program for entering the turn and the program for exiting the turn. The algorithm of transition programs depends on the chosen order of turns and in each specific case depends on the design features of the product. To test the developed methodology, a test calculation of the front horizontal tail of a light aircraft was carried out. As a result of the work done, it was possible to solve the problem of modeling the RM laying trajectory for bodies of complex shape with a fixed type of section, manufactured by the winding method from a polymer composite material (PCM). This technology can be used to produce aircraft structures such as “wing”, “fuselage” of an airplane, helicopter, and the like. Thus, the possibility of winding a general type AS has been proven using the example of the horizontal front tail of a light aircraft. The range of production of wound products has expanded - bodies with an arbitrary convex section and a straight generatrix. A technology has been developed for manufacturing from PCM by winding non-axisymmetric aerodynamic power structural elements such as aircraft wings, helicopter blades, air and water propellers. A surface reinforcement scheme has been found that makes it possible to obtain a variable wall thickness with its decrease from the root to the end rib. The trajectories of laying reinforcing material on a surface with an arbitrary convex section and the movement of working parts for a three-axis winding machine are determined. The developed calculation method can be used to create various aerodynamic structural elements with positive surface curvature from PCM by winding. The use of advanced high-performance technology for automated winding of reinforcing fiber material provides a significant reduction in labor costs in the manufacture of these units, reducing their prices compared to the prices of existing metal and composite aircraft of comparable size and equipment

Short-Glass-Fiber Aspect Ratios in Polyamide-6 Composites: Homogenization and Deep Learning-Based Scanning Image-Microscope Segmentation Comparison

This paper presents a comparative analysis of fiber aspect ratios using scanning electron microscopy (SEM) and the mean field homogenization approach. The novelty of this work lies in an effective fiber length evaluation based on a comparative analysis of fiber aspect ratios using scanning electron microscopy (SEM) and the mean field homogenization approach. This makes it possible to use an electron microscope to image fiber samples corresponding to the sample size using microtomography. Molded samples and pellets of four polyamide-6 short-glass fiber-reinforced composites with mass fractions of 15%, 30%, and 50% were considered. The aspect ratio distribution measured by SEM for the investigated materials was 20.25 with a coefficient of variation of 5.1%. The fiber aspect ratio obtained based on mean field homogenization theory and the tensile curve approximation was underestimated at 13.698 with a coefficient of variation of 5.2%. The deviation between the micro- and macro-estimates can be represented as a mean effective aspect ratio of 68% with a coefficient of variation of 8.5%. The developed technology for preparing samples for SEM and automated image processing can be used to study other short-reinforced polymer composite materials. The obtained estimates can serve as a useful reference when calibrating other models of short-fiber-reinforced polymer materials.

STUDY OF RHEOLOGY PROPERTIES OF POLYMER COMPOSITE MATERIALS

This article presents the results of the study of the rheological properties of polymer composite ma-terials based on glass microgranules containing high-density polyethylene. The flow curves of the obtained compositions were obtained by the capillary viscometry method. On the basis of the conducted research, simple mathematical models were built, which allow to estimate the viscosity values of the alloys based on the given filler content. Keywords: polyethylene, glass microgranules, polymer composite materials, rheological proper-ties.

Reverse Osmosis Membrane Engineering: Multidirectional Analysis Using Bibliometric, Machine Learning, Data, and Text Mining Approaches.

Membrane engineering is a complex field involving the development of the most suitable membrane process for specific purposes and dealing with the design and operation of membrane technologies. This study analyzed 1424 articles on reverse osmosis (RO) membrane engineering from the Scopus database to provide guidance for future studies. The results show that since the first article was published in 1964, the domain has gained popularity, especially since 2009. Thin-film composite (TFC) polymeric material has been the primary focus of RO membrane experts, with 550 articles published on this topic. The use of nanomaterials and polymers in membrane engineering is also high, with 821 articles. Common problems such as fouling, biofouling, and scaling have been the center of work dedication, with 324 articles published on these issues. Wang J. is the leader in the number of published articles (73), while Gao C. is the leader in other metrics. Journal of Membrane Science is the most preferred source for the publication of RO membrane engineering and related technologies. Author social networks analysis shows that there are five core clusters, and the dominant cluster have 4 researchers. The analysis of sentiment, subjectivity, and emotion indicates that abstracts are positively perceived, objectively written, and emotionally neutral.