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This task is intended to perform impact tests with a low-speed test on the specimen. The tests are carried out to improve their tolerance of impact so that they can be used for realistic applications in the real world. The specimen is treated with acid and a base for one day. By the hand-laying method, the specimen shall be prepared. Microscopy of the electron scanning is carried out in order to receive data on the surface topography of the affected specimen. Various low speed experiments have been evaluated in this paper.

The composite material is made of different materials. It retains the advantages of the original material and reflects combined characteristics of all the constituents. Polymer matrix composites are popular in the recent industrial applications. Friction and wear governs the tribological aspects of polymer composites. This paper revel the experimental study of friction and wears behavior of epoxy composites filled with bronze and graphite fillers as per ASTM standards. Three compositions were studied and it was found that composition ‘A’ has lowest coefficient of friction (0.281) whereas composition ‘C’ has highest coefficient of friction (0.325). The composition ‘A’ has lowest wear rate of 0.5 μm/s and composition ‘C’ showed highest wear rate of 3.25 μm/s. Use of graphite and bronze along with epoxy exhibited formation of lubricating layer and enhanced friction and wear behavior of the composites.

The chemical precipitation was used to obtain carbon fibers (CF) with surface modified by magnetite particles (Fe3O4). Processing was carried out by employing up to three subsequent coating stages ...

Date palm fibre is considered as an agricultural waste suitable as reinforcement for polymeric composites has received interest as an interior component in the automotive industry. The aim of this work to investigate the physical and mechanical properties of date palm fibre (leaf stalk, tree trunk, fruit stalk and leaf sheath) reinforced epoxy composites and date palm/bamboo hybrid composites suitable for non-structural and semi-structural applications. The different composites were fabricated using a hand lay-up technique in combination with compression moulding method. Date palm fibre/bamboo hybrid composite, and pure composites were characterized by various mechanical testing such as tensile, flexural and low-velocity impact testing. Exposure to liquid water and environmental conditions affect the durability of biobased composites. The water absorption behaviour and its effects on the thickness swelling, changes in density and physical performance of different composites were further investigated. The experimental results of the date palm fibre/bamboo hybrid composite exhibited the highest mechanical properties compared to date palm fibre composite without hybridisation. The tensile strength, flexural strength and impact toughness values for the date palm/bamboo hybrid composite were recorded at 39.16 MPa, 61.10 MPa and 12.70 J/m, respectively. Interestingly, the physical test of thickness swelling and water absorption results has indicated that date palm fibre/bamboo hybrid composite displayed 27.68% and 15.39% less when compared with single date palm fibre composite. Therefore, the results have discovered that the date palm fibre/bamboo hybrid composite has the prospective to be applied as a non-structural and semi-structural components.

A syntactic foam was prepared from an epoxy resin matrix and modified hollow glass microsphere fillers. Modification by silane coupling agents with different molecular structures was analyzed, and the optimal content of the silane coupling agent was determined. The results demonstrated that all silane coupling agents enhanced the adhesion between the hollow glass microspheres and epoxy resin matrix, resulting in enhanced water absorption, compressive performance, tensile performance, and bending performance compared to those prepared using unmodified hollow glass microspheres. Among silane coupling agents with different end groups, the one with a sulfhydryl end group exhibited optimal modification for hollow glass microspheres. Among the silane coupling agents with different backbone structures, the one with silanol groups exhibited the optimal modification of hollow glass microspheres. Additionally, the performance of the syntactic foams was optimal when 6% of the silanol-containing coupling agent was used. The results demonstrated that syntactic foams prepared with hollow glass microspheres modified by silane coupling agents exhibited improvements in water absorption, compressive performance, tensile performance, and bending performance, compared with those prepared using unmodified hollow glass microspheres. Among silane coupling agents with different end structures, the one with a sulfhydryl group as end group showed the best modification effect on hollow glass microspheres. The water absorption was 0.35%, the compressive strength was 62.15 MPa, the tensile strength was 40.15 MPa, and the bending strength was 53.17 MPa. Among silane coupling agents with different backbone structures, the one with silanol groupsbonds showed the best results. Its compressive strength was up to 64.15 MPa, the tensile strength was 35.47 MPa, and the bending strength was 53.99 MPa.

The hybrid fillers (Al2O3–ATP hybrids) composed of two types of inorganic materials—modified alumina (Al2O3) and modified attapulgite (ATP)—were principally prepared, following which the epoxy matrix (EP) composites reinforced with Al2O3–ATP hybrids were synthesized. The mechanical and dynamic mechanical properties of fabricated Al2O3–ATP/EP composites are enhanced by doping Al2O3–ATP hybrids into EP. The highest impact and flexural strength of EP composites (3 wt% Al2O3–3 wt% ATP/EP) are improved to 27.88 kJ/m2 and 157.04 MPa, which are 457.6% and 89.2% higher than those of the pure epoxy resin, respectively. The glass transition temperature of Al2O3–ATP/EP composites increases by 8.8 °C, compared with pure EP composites and the dielectric constant and dielectric loss can reach 3.19 and 0.0041 at 100 Hz. These excellent mechanical and dynamic mechanical properties, accompanied by dielectric property may expand the practical applications of EP composites in industrial engineering.

Hypothesis Polysiloxanes are becoming new trend in self-cleaning (oil- and water‐repellent) applications due to their low-cost and environmentally friendly nature. Lower phase separation of polysiloxanes in coating matrix is critical to obtain excellent self-cleaning properties. We hypothesize that telechelic polysiloxanes can bind to coating matrix at both ends and thus will suppress phase separation of polysiloxane as compared to hemi-telechelic analog and thus will offer excellent self-cleaning properties. Experiment Eight PDMS additives were prepared via the free-radical polymerization of telechelic and hemi-telechelic methacryloxypropyl-based PDMS precursors with methylmethacrylate (MMA) and glycidylmethacrylate (GMA). The compositions of the prepared polysiloxane additives were optimized to obtain excellent self-cleaning performance. Findings Our breakthrough development confirms that telechelic polysiloxanes (PDMS-T) incorporated into epoxy-based anti-smudge coatings outperform hemi-telechelic polysiloxanes (PDMS-HT) by offering excellent repellency against difficult to repel liquids. These breakthrough findings will vertically advance Science and innovations in the self-cleaning field by offering robust guidelines for choosing suitable polysiloxane for self-cleaning applications.

The Mode-I interlaminar fracture characteristics of aramid fabric andcarbon fabric reinforced epoxy composites along with the influence of SiC particle content were explored. Double cantilever beam (DCB) tests were performed in accordance with ASTM D 5528 for the purpose of examining the behavior of Mode-I delamination. The results showed that, the adhesion strength of an SiC particle within an aramid/ epoxy composite system was better than that within a carbon/epoxy composite system. The highest values of Mode-I fracture toughness of an aramid fabric/epoxy specimen and a carbon fabric/epoxy specimen were 1391 J × m-2 and 701 J × m-2 with SiC particle contents of 10 wt.-% and 5 wt.-%, respectively. The micrographs from optical and scanning electron microscopes verified the enhancements of Mode-I interlaminar fracture toughness behavior.

This work is intended to explore the influence of barite particulate filler on the mechanical behaviour of carbon fiber (Cf) reinforced polymer matrix (CFRP) composites. The carbon fiber utilized for the study was T300 grade and the polymer matrix utilized was LY556 epoxy resin (Epr). The CFRP composites prepared with 55 weight (wt.) % T300 carbon fiber and 45 wt.% LY556 epoxy resin without barite particulate filler was utilized for control experimentation. The CFRP composites with barite filler were prepared by varying the proportion of barite particles from 2.5 wt.% to 15 wt.% in steps of 2.5 wt.%. The composites were prepared using the hand lay-up process and the barite particles were mixed with the epoxy resin by means of ultrasonic agitation. The prepared composites were subjected to tension, compression, hardness, flexural and impact testing. The CFRP composites with 10 wt.% barite particles yielded the best tensile strength, hardness and impact strength. The tensile strength, hardness and impact strength attained an increase of 13.18%, 5.6% and 18.68% respectively, compared to the CFRP composite without barite filler. The compressive strength of the CFRP composite with 15 wt.% barite filler was observed to be more than twice the compressive strength of the CFRP composite without barite filler. However, the flexure strength reduced steadily with the addition of barite particulates. The fractured surface morphologies of the prepared composites were characterised using the Scanning Electron Microscope (SEM). The chemical composition and morphology of barite powder was analysed using Energy Dispersive X-Ray Spectroscopy (EDX) and SEM, respectively.

In this work, the object of study is an epoxy nanocomposite based on TiO2 nanoparticles and epoxy resin, and the subject is the preparation and physical and mechanical properties of TiO2/epoxy nanocomposites. The characteristics of the properties and methods of synthesis of the initial components for the synthesis of epoxy nanocomposites - epoxy resins and nanoparticles of titanium dioxide are given, and data on epoxy nanocomposites based on nanoparticles of titanium dioxide are presented. It was found that the addition of TiO2 to the epoxy matrix reduces the coefficient of friction and significantly increases the wear resistance of such nanocomposites.

The growing environmental awareness in the last few decades has driven the research and development of composites reinforced with natural fibers as an alternative to replace synthetic fiber composi...

Spent coffee grounds (SCGs) represent a huge amount of global waste whose post-use disposal triggers environmental issues. In this study, SCGs were successfully treated and modified to improve the mechanical properties of biobased composites with epoxy matrix. A two-step treatment was proposed, pretreating by a NaOH solution and modifying by maleic anhydride (MA). MA acts as a coupling agent to create the internal network in composite through the interaction between functional groups. Accordingly, MA improves the interface between phases in composite, ensures a better physical property compared to the composite without modification. Consistently, the two-step treatment depicts improved mechanical properties: flexural modulus and flexural strength increased to 3053 MPa and 45 MPa, respectively, compared to 2429 MPa and 33 MPa for composite with pure SCGs.

The present study examined the effects of drilling parameters such as spindle speed (N), feed rate (f), diameter of the tools (d) and drill geometry such as twist drills (HSS-TiN) and brad & spur drills (BSD) used on delamination damage in a biosandwich structure consisting of an epoxy matrix reinforced with bidirectional jute fibres and cork (JFCE). Response surface methodology (RSM) and artificial neural networks (ANNs) were exploited to evaluate the influence and interaction of the cutting parameters on the delamination factor (Fd) at the output during drilling. In addition, several optimization methods, such as desirability-based RSM, the genetic algorithm (GA) and the fmincon function, were applied to validate the optimal combination of cutting parameters (f, N and d) in the structures studied in biosandwiches during this research. According to the experimental results, severe damage was indeed observed with the BSD tool (Fd = 1.684) compared to the HSS-TiN tool (Fd = 1.555) for the same cutting conditions. To obtain the minimum Fd, the optimum conditions obtained by GA were respectively 1397.54 rev/min, 51.162 mm/min and 5.981 mm for HSS-TiN for f, N and d.

The widespread use of polymer-based composite materials made it possible to replace expensive metal alloys, increase the strength indicators of structures and improve tribotechnical properties. Their use as protective coatings for structural elements operating in an abrasive environment has yielded good results in increasing wear resistance, which is especially important for parts of tillage tools. (Research purpose) The research purpose is in studying the influence of the composition and size of the fractions of the composite gravel filler with an epoxy matrix on its wear. (Materials and мethods) The article considers five composite materials with different compositions. The prototypes were hollow cylinders with dimensions that provide the contact area necessary for the passage of all processes of abrasive wear. The abrasive composition consisted of a mixture of sand and gravel with a fraction size of about 30-40 millimeters. (Results and discussion) The changes in the wear over time are directly proportional and this confirms the classical views on the wear process. The experiments was conducted on the installation of authors’ design. (Conclusions) The wear over time for experimental composites is the same and is expressed in a straight- line relationship; the maximum wear resistance is a composite in which gravel particles have a size of 2.25 millimeters with its content in the matrix of about 60 mass parts. At the same time, gravel with an effective diameter of 2.25 millimeters creates optimal conditions for self-organization of the wear process and provides a relatively low value of the friction coefficient.

Composite materials with nanofibrous reinforcements are capable of high mechanical performance and enhanced properties despite their low volume fraction of reinforcement. In this study, tensile properties of epoxy-matrix nanocomposites were investigated after reinforcing by hand layup method implementation of randomly oriented electrospun nanofiber layers. The reinforcements were produced from polyacrylonitrile (PAN), Polyamide-6,6 (PA-6,6), and their 50/50 hybrid. The results indicated that PAN enhanced the tensile toughness of the matrix by almost 4 times, increasing both the ductility (an expected 23% due to fiber being more elastic than the matrix) and the ultimate tensile strength (a surprising 35% even though the fibers were less stiff than the matrix). These results indicate significant improvements in the impact properties for advanced applications. The results revealed that PA-6,6 did not show the characteristics of a promising reinforcement whether used solely or added to PAN.

The failure of carbon fiber reinforced epoxy matrix composites has been attributed to different mechanisms involving tensile, compressive and shear failure of the fibers or the matrix. This researc...

This study investigated the effects of loadings of cellulose nanocrystals (CNC) extracted from jute fibers on the chemical, mechanical and thermal properties of the Epoxy matrix. The CNC/Epoxy comp...

“Green” thermally stable hardener was synthesized from a PET waste. The rigid molecular linear structure of the new hardener suggests that it will provide the polymer matrix with the necessary physical and mechanical characteristics. It also allows the expectation that cured matrix based on this hardener can provide increased toughness. New hardener was used as a curing agent for three epoxy resins—tetraglycidyl methylenedianiline (TGDMA, 111–117 EEW), diglycidylether of bisphenol A (DGEBA, 170-192 EEW) and solid epoxy resin (SER)—with a medium molecular weight (860–930 EEW) based on DGEBA. The mixtures were found to have the highest Tg for the DGEBA resin, and high of that for TGDMA and SER. According to the DMA analysis for two cured matrices, the hardener proved to be no worse than the standard ones, and made it possible to obtain cured matrices with excellent mechanical properties, which allows us to hope for further application of new hardener cured epoxy matrices in appropriate composite materials at high temperatures.

This article presents the mechanical, physical, and tribological properties of the boron carbide (B4C) reinforced epoxy matrix composites (BEMCs). The BEMC samples were prepared with various B4C concentration of 0%, 1%, 2%, 3%, and 5%. B4C particles were treated with a silane coupling agent to ensure efficient adhesion with epoxy. The influence of a range of parameters (particle loading, sliding speed, sliding distance, and normal load) on the wear and friction behavior of BEMCs were evaluated by conducting wear tests under dry sliding conditions on a pin-on-disc wear test set-up. The addition of B4C to the epoxy polymer improved the wear resistance of the composites. Maximum wear resistance and coefficient of friction were observed for the composite with the highest percentage of B4C (5%). The specific wear rate was reduced on increasing load and sliding distance and increased with the sliding velocity. Mechanical properties including compression strength, flexural strength, and impact energy, along with physical properties such as density and hardness, were also evaluated. B4C particles improved the hardness, density, flexural and compression strength, and impact resistance of the composites. Scanning electron microscope (SEM) analysis of the worn-out surfaces and flexural fractured surfaces was carried out to predict the possible wear and fracture mechanisms. Micro-ploughing, abrasion, and adhesion were the wear mechanisms in BEMCs. Under the flexural loads, particulate de-bonding, pull-out, and brittle fracture of the matrix were the governing failure mechanisms.

The change in the abrasive resistance under testing composites based on an epoxy matrix filled with sludge originating from cutting tool sharpening exhibits the same character for all compositions, which reflects the process of wear self-organization. A composite filled with abrasive particles originating from grinding wheels has the maximum abrasive wear resistance.

Для полимерных композиционных материалов (ПКМ) с армирующим наполнителем из растительных волокон одним из актуальных вопросов является обеспечение надёжной межфазной связи волокно-матрица. Предметом экспериментального исследования явились образцы микропластика из элементарных волокон стебля крапивы (Urtica dioica L.) и эпоксидной матрицы. Цель исследования – оценка межфазной связи образцов микропластика на основе элементарного волокна стебля крапивы и эпоксидного связующего. В экспериментальных исследованиях использованы методы микромеханических испытаний и оптической микроскопии. Из стеблей крапивы ранневесеннего сбора выделены элементарные волокна длиной до 70 мм. Для получения микропластика использовано связующее на основе эпоксидиановой смолы ЭД-20 и ангидридного отвердителя ХТ-152Б. Приготовлены образцы микропластика с одиночными элементарными волокнами. Проведены микромеханические испытания на фрагментацию одиночного волокна. Волокна испытаны на растяжение на испытательной разрывной машине со скоростью движения траверсы 5 мм/мин. Ширина поперечных сечений волокон переменна по длине и составляет от 5 до 30 мкм, соотношение размеров (ширина-толщина) достигает 1:1,5. Вытягивание волокна при разрушении образца микропластика сравнительно невелико и достигает 135 мкм, что соответствует от 8 до 10 величин поперечного размера сечения волокна вместе его вытягивания. Минимальная длина фрагментов составляет 165 мкм. Прочность межфазной адгезии волокно-матрица может быть оценена на уровне 1,38 МПа. Характер разрывов волокон свидетельствует о хрупком механизме его разрушения. Подтверждено, что межфазная связь волокно-матрица в изученных образцах ПКМ объясняется механизмом механической блокировки. Результаты экспериментального исследования могут быть применены для создания ПКМ на основе натуральных волокон и эпоксидной матрицы. For natural fibers reinforcing polymer composite (NFRPs), one of the topical issues is to ensure a reliable fiber-matrix interfacial bond. The subject of the experimental study was samples of microplastics from elementary fibers of the stalk of nettle (Urtica dioica L.) and an epoxy matrix. The aim of the study is to assess fiber-matrix interface of microplastic samples based on elementary nettle stem fiber and an epoxy binder. The experimental studies used the methods of micromechanical testing and optical microscopy. Elementary fibers up to 70 mm in length were isolated from the stalks of early spring nettle. To obtain microplastics, a binder based on ED-20 epoxy resin and HT-152B anhydride hardener was used. Samples of microplastics with single elementary fibers were prepared. Micromechanical tests for fragmentation of a single fiber have been carried out. The fibers were tensile tested on a tensile testing machine at a crosshead speed of 5 mm / min. The width of the cross-sections of the fibers is variable along the length and ranges from 5 to 30 microns, the size ratio (width-thickness) reaches 1:1.5. Fiber elongation during destruction of a microplastic sample is relatively small and reaches 135 μm, which corresponds to 8 to 10 times the cross-sectional dimension of the fiber along with its elongation. The minimum fragment length is 165 µm. The interfacial adhesion fiber-matrix strength can be estimated at 1.38 MPa. The nature of the fiber breaks testifies to the fragile mechanism of its destruction. It was confirmed that the fiber-matrix interface in the studied NFRPs samples is explained by the mechanism of mechanical blocking. The results of the experimental study can be used to create a NFRPs based on natural fibers and an epoxy matrix.

The random distribution of graphene in epoxy matrix hinders the further applications of graphene-epoxy composites in the field of tribology. Hence, in order to fully utilize the anisotropic properties of graphene, highly aligned graphene-epoxy composites (AGEC) with horizontally oriented structure have been fabricated via an improved vacuum filtration freeze-drying method. The frictional tests results indicated that the wear rate of AGEC slowly increased from 5.19×10−6 mm3/(N·m) to 2.87×10−5 mm3/(N·m) with the increasing of the normal load from 2 to 10 N, whereas the friction coefficient (COF) remained a constant of 0.109. Compared to the neat epoxy and random graphene-epoxy composites (RGEC), the COF of AGEC was reduced by 87.5% and 71.2%, and the reduction of wear rate was 86.6% and 85.4% at most, respectively. Scanning electron microscope (SEM) observations illustrated that a compact graphene self-lubricant film was formed on the worn surface of AGEC, which enables AGEC to possess excellent tribological performance. Finally, in light of the excellent tribological properties of AGEC, this study highlights a pathway to expand the tribological applications of graphene-epoxy composites.