Properties Of Epoxy Composites Research Articles

Evaluation of the thermomechanical properties of novel epoxy composites reinforced with Geonoma baculifera fibers

Natural lignocellulosic fibers (NLFs) have shown a great potential as reinforcements in composites in recent decades. Among other reasons, environmental concerns and the depletion of oil reserves justify research on natural composites as they offer an environmentally friendly alternative and align with the principles of sustainable development. Among the plethora of NLFs available in nature, the ubim fiber (Geonoma baculifera) has not yet been investigated as a reinforcement for composites in potential engineering applications. Therefore, this study evaluates, for the first time, the mechanical properties of epoxy composites with 10, 20, and 30 vol% of ubim fibers. These properties were assessed through Izod impact, tensile and flexural tests as well as dynamic mechanical analysis (DMA). The data were statistically analyzed using the ANOVA method. Scanning electron microscopy (SEM) analysis indicated a transition from a purely brittle fracture mechanism to a ductile-brittle combination as the fiber volume in the composite increased. Tensile tests of the composites demonstrated an increasing trend in strength and elastic modulus with fiber volume. The results of the flexural tests also displayed a similar trend in strength and elasticity modulus for the composites. The results of DMA tests showed that composite materials with a 30 vol% of ubim fibers exhibited a high glass transition temperature and a low tan δ value, suggesting higher stiffness of this composite compared to others. Overall, the results indicated that the incorporation of 30 vol% ubim fibers into the composites significantly improved their mechanical properties compared to other tested fiber fractions. Additionally, their functional characteristics, such as simplicity in the manufacturing process, low cost, and excellent strength-to-weight ratio, make these composites particularly suitable for applications in sectors such as the automotive industry, construction panels, and packaging. These factors contribute to the development of an efficient, sustainable, recyclable and environmentally friendly composite.

A study of the friction and thermal properties of epoxy composites synergistically reinforced by open-celled Cu foams and carboxylated CNTs

A study of the friction and thermal properties of epoxy composites synergistically reinforced by open-celled Cu foams and carboxylated CNTs

Enhancing Mechanical and Tribological Properties of Epoxy Composites with Ultrasonication Exfoliated MoS2: Impact of Low Filler Loading on Wear Performance and Tribofilm Formation.

This study highlights the impact of low amounts of MoS2 quantities on composite performance by examining the effects of ultrasonication exfoliated MoS2 at different loadings (0.1-0.5 wt%) on the mechanical and tribological parameters of epoxy composites. Even at low concentrations, the ultrasonication and exfoliation procedures greatly improve the dispersion of MoS2 in the epoxy matrix, enabling its efficient incorporation into the tribofilm during sliding. Optimum mechanical properties were demonstrated by the MoS2/epoxy composite at 0.3 wt%, including a modulus of elasticity of 0.86 GPa, an ultimate tensile strength of 61.88 MPa, and a hardness of 88.0 Shore D, representing improvements of 61.5%, 35.45%, and 16.21%, respectively. Corresponding tribological tests revealed that high sliding velocity (10 N load, 0.2 m/s) resulted in a 44.07% reduction in the coefficient of friction and an 86.29% reduction in wear rate compared to neat epoxy. The enhanced tribological performance is attributed to the efficient removal and incorporation of MoS2 into the tribofilm, where it acts as a solid lubricant that significantly reduces friction and wear. Even though an ultra-low amount of filler concentration was added to the composite, a unique finding was the high MoS2 content in the tribofilm at higher sliding speeds, enhancing lubrication and wear protection. This study establishes that even ultralow MoS2 content, when uniformly dispersed, can profoundly improve the mechanical and tribological properties of epoxy composites, offering a novel approach to enhancing wear resistance.

Construction of “organic–inorganic” hierarchical structure of carbon fibers and the effect on the properties of epoxy composites

AbstractThe demand for epoxy (EP) in semiconductor, aerospace, and other applications is currently on the rise. However, pure epoxy is difficult to meet these requirements, such as low thermal conductivity and poor toughness. Therefore, in this paper, sulfonamides (SAs) and core‐shell silica (SLC‐SiO2) were grafted onto the surface of short carbon fibers (SCF) with sizes of 0.1–6 mm by the chemical grafting method. As a result, the surface activity of SCF was improved and the interfacial properties of the EP composites were enhanced. The interfacial compatibility of SCF grafted with SAs and SLC‐SiO2 in EP is greatly improved, resulting in stronger mechanical interlocking and chemical bonding ability between EP and SCF. The results showed that when the content of SCF@SAs@SLC‐SiO2/EP composites reached 0.3 wt% of SCF@SAs@SLC‐SiO2, the impact and tensile strengths were increased from 12.15 kJ·m−2 and 43.4 MPa to 16.93 kJ·m−2 and 74.97 MPa compared with the pure epoxy, which were improved 39.3% and 72.7%. In addition, the thermal conductivity of SCF@SAs@SLC‐SiO2/EP composites was also improved by 12.5% from 0.205 W·(m·K)−1 to 0.2306 W·(m·K)−1 compared with the pure EP. This is due to improved chemical interactions and mechanical interlocking at the fiber‐epoxy interface. This study provides a new method for the preparation of high‐performance SCF/EP composites.Highlights The amino group of sulfonamides was grafted with short carbon fiber to increase the surface active group of short carbon fiber. Sulfonamides react with carboxyl groups on the surface of core‐shell silica to form an “organic–inorganic” structure. Improve the surface roughness of short carbon fiber, and make it evenly dispersed in epoxy resin, so as to improve the performance of epoxy composite materials.

Non-linear AC dielectric properties of epoxy composites filled with core–shell SiC particles

Abstract Core–shell structured silicon carbide (SiC)/epoxy (EP) composites exhibit superior non–linear DC conductivity. However, the high voltage alternative current dielectric properties of the composites are rarely reported. In this paper, the time–domain measurement was employed to obtain the basic dielectric characteristics, AC conductivity, and relative permittivity of the SiC/EP and SiC@Al2O3/EP composites under less than the breakdown strength of the SiC/EP (i.e. the amplitude of 1–5 kV mm−1). In addition, in the high AC electric field (i.e. the amplitude of 6–20 kV mm−1), the non–linear AC dielectric properties of the SiC@Al2O3/EP composite are also investigated. The experimental results suggest that the SiC@Al2O3/EP composite shows more obvious non–linear AC dielectric properties than the SiC/EP composite. In the high AC electric field, the AC conductivity of the SiC@Al2O3/EP composite presents the relaxation phenomenon, which is attributed to the excitation field and its derivative. This work lays a foundation for further research on the AC steady–state and transient dielectric properties of the field grading materials, which are widely used to homogenize the nonuniform electric field distribution in many electrical and electronic equipment.

Mechanical properties of epoxy composites filled with multi-walled carbon nanotube, Nanoaluminum particles and glass fibers at elevated temperatures

The present work investigates the mechanical properties of a composite material composed of multi-walled carbon nanotubes (MWCNTs), nano-aluminum powder (NAP), and glass fibers (GF) for five different compositions. The study further investigated how MWCNTs contribute to maintaining the mechanical properties of nanocomposites when exposed to elevated temperatures, up to 180 °C. The evaluation of impact strength revealed that the nanocomposite, composed of 2 % MWCNTs, 15 % NAP, and 10 % GF, demonstrated the greatest impact strength. At room temperature, the composite containing 2 % MWCNTs, 5 % NAP, and 20 % GF exhibited the highest ultimate tensile strength (UTS). Conversely, at elevated temperatures reaching up to 180 °C, the highest UTS was observed in the composition with 2 % MWCNTs, 10 % NAP, and 15 % GF. The hardness of the nanocomposite was influenced by its composition; at room temperature, the maximum hardness was observed in the mixture containing 2 % MWCNTs, 20 % NAP, and 5 % GF. In contrast, at elevated temperatures, the composition with 2 % MWCNTs, 5 % NAP, and 20 % GF exhibited the highest hardness. Overall, the study found that incorporating GF and NAP improved the mechanical properties of the composite. These results indicate that the composite's performance could be further optimized for specific applications through the addition of filler materials.

Enhanced morphological and thermal properties of epoxy composites reinforced with Palm and Prosopis Juliflora fibers

Abstract This study investigates the fabrication and characterization of a hybrid epoxy matrix composite reinforced with Palm and Prosopis Juliflora fibers fabricated using the hand layup technique. Three composite samples were prepared with varying weight percentages of palm and Prosopis Juliflora fiber reinforcements: 5% (Sample A), 10% (Sample B), and 15% (Sample C). Sample B having 10 weight percentage each of Palm fiber and Prosopis Juliflora fiber and 80 weight percentage of Epoxy matrix, exhibited superior performance with a tensile strength of 45.5 MPa and a hardness of 86.5 Shore D. Thermal analysis revealed Sample B’s exceptional thermal stability, with distinct decomposition stages observed through Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA). Void content analysis indicated Sample C had the lowest void content at 4.5%. Energy Dispersive x-ray (EDX) Analysis confirmed homogeneous fiber distribution and strong fiber-matrix adhesion, supported by carbon and oxygen peaks. Fourier-transform infrared spectroscopy (FTIR) spectra showed interactions between functional groups, including alcohols, carboxylic acids, and carbonyl compounds. These findings underscore the composite’s potential for high strength, toughness, and thermal stability applications.

Epoxy Composites with Post-Production Gray Cast-Iron Powders.

Processing of cast-iron castings by machining is associated with a large amount of post-production waste in the form of cast-iron chips, which constitute up to about 5% of the weight of the entire casting. In the case of serial production, this generates large amounts of post-production waste, constituting a constantly growing scale of environmental problems. The aim of this research was to develop a simple and cheap method of utilizing post-production waste of gray cast-iron chips from the machining process for the production of small structural elements of water supply fittings. The analysis of the state of knowledge indicates that the simplest method of managing waste chips is to use them as a starting material in the process of manufacturing polymer composites. The most frequently chosen material for the matrix of polymer composites reinforced with metal powders is epoxy resin. The epoxy composite was produced by the vacuum-assisted casting method. This paper presents the results of tests of morphological, mechanical, and corrosion properties of epoxy composites filled with grey cast-iron powder with a grain size below 0.075 mm and a mass content in the composite of 65%. The composite cured at 130 °C for 90 min had the best mechanical properties. The sample cured at 130 °C for 90 min was observed to have the optimum effect, with a tensile strength of 28.35 MPa, a flexural strength of 55.4 MPa, and a compressive strength of 53.8 MPa. All tested composites were characterized by very good thermal resistance and, in comparison to gray cast iron, over 2.5 times lower weight and an over three times lower corrosion rate in the tap water environment.

Epoxy resin reinforced with carbonized chicken feathers: An innovative composite material with sustainable potentials

This article explores a novel method for enhancing the mechanical properties of epoxy resin composites by incorporating carbonized chicken feathers as a filler material. The fabrication process involves carbonizing chicken feathers at 600°C and incorporating 5-10 wt% of the fillers into an epoxy matrix. The composites showed enhanced mechanical properties and samples containing 10 wt% filler exhibit the best properties. The performance corresponds to 49% increase in tensile strength, 16% rise in Young’s modulus, 40% improvement in flexural modulus, and 57% in flexural strength. X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy were employed to characterize the filler. This characterization provides valuable insights into the structure and chemical composition of the pulverized carbonized chicken feathers that contributed to the attained improvement in composites’ properties. Microstructural examination of the developed composite under scanning electron microscope also provides insights into matrix-filler interface and dispersion of the fillers within the composite matrix. The study not only highlights the unique combination of carbonized feathers’ inherent strength and compatibility with the epoxy matrix but also underscores the eco-friendly nature of utilizing agricultural waste. The findings suggest promising applications in industries demanding lightweight, high-strength materials, which can contribute to sustainable engineering solutions.

Enhancing epoxy composite materials through lime‐treated sugarcane bagasse and glass fiber reinforcement: Morphological, mechanical, and flame‐retardant insights

AbstractThis study investigates the utilization of sugarcane bagasse and glass fiber to reinforce epoxy composites, enhancing both mechanical and fire resistance properties. Initially, bagasse is collected, sun‐dried, and finely ground before being treated with lime water at concentrations of 3%, 5%, and 7% by weight. The treated bagasse is then mixed with epoxy resin and a hardening agent, followed by a curing process. For samples incorporating glass fibers, the fibers are manually integrated and cured similarly. The methodology involved detailed preparation of the bagasse, its treatment, and subsequent integration with epoxy resin. The mixture was processed under controlled conditions to ensure uniformity and quality. Mechanical properties such as tensile strength, flexural strength, compressive strength, and impact resistance were measured. Thermogravimetric analysis (TGA) was employed to assess thermal stability, while fire resistance was evaluated using the limiting oxygen index (LOI) and the 94‐V test method. Results demonstrated significant improvements in both mechanical and thermal properties with the addition of bagasse and glass fibers. The optimal treatment was identified at a 5% lime water concentration, yielding a tensile strength of 295.08 MPa, flexural strength of 371.24 MPa, compressive strength of 255.39 MPa, and Izod impact strength of 157.04 kJ/m2. TGA results showed the highest thermal stability at 5% concentration, with decomposition temperatures peaking at 402.52 °C. Fire resistance was markedly enhanced, achieving an LOI of 29.8% and meeting V2 level standards according to the 94‐V test method. In conclusion, treating sugarcane bagasse with a 5% lime water solution significantly enhances the mechanical and fire‐resistant properties of epoxy composites. The combination of sugarcane bagasse and glass fiber creates a robust material with high thermal stability and fire resistance, making it a viable option for applications requiring these enhanced properties.

Characterization, impact and wear properties of treated and as-received graphene nanosheets reinforcement in epoxy resin composites

PurposeThis study aims to explore the enhancement of mechanical properties in epoxy resin composites through the incorporation of graphene nanoparticles, focusing on their impact and wear resistance. It investigates the role of graphene, both treated and untreated, as a reinforcing agent in composites, highlighting the significance of nanoparticle dispersion and surfactant treatment in optimizing mechanical performance.Design/methodology/approachEmploying a novel dispersion technique using a drawing brush, this research contrasts with traditional methods by examining the effects of graphene nanoparticle concentrations treated with surfactants – Polyvinylpyrrolidone (PVP) and Sulphonated Naphthalene Formaldehyde (SNF) – on the mechanical properties of epoxy resin composites. The methodology includes conducting a series of impact and wear tests to assess the influence of graphene reinforcement on the composites' performance.FindingsThe findings reveal a marked enhancement in the composites impact resistance and energy absorption capabilities, which escalate with an increase in graphene content. Additionally, the study demonstrates a significant improvement in wear resistance, attributed to the superior mechanical properties, robust interface adhesion and effective dispersion of graphene. The use of surfactants for graphene treatment is identified as a crucial factor in these advancements, offering profound insights into the development of advanced composite materials for diverse industrial uses.Originality/valueThis study introduces a unique dispersion technique for graphene in epoxy composites, setting it apart from conventional methods. By focusing on the critical role of surfactant treatment in enhancing the mechanical properties of graphene-reinforced composites, it provides a novel insight into the optimization of impact and wear resistance.

Analyzing the impact of TiO2 filler on the wear characteristics of flax fiber-reinforced epoxy composite using the Taguchi approach

Purpose This study aims to investigate the impact of titanium oxide (TiO2) filler on the coefficient of friction (COF) and specific wear rate (SWR) in flax fiber reinforced epoxy composites (FFRCs) under abrasive wear conditions utilizing the Taguchi approach. The primary objective is to enhance wear resistance and promote the development of sustainable materials for various applications. Design/methodology/approach Epoxy/flax composites with varying TiO2 filler content (0–8 wt%) are fabricated through the hand layup method. Subsequently, wear testing is conducted following ASTM G99-05 standards. The Taguchi design of experiments (DOE) and analysis of variance (ANOVA) are utilized for statistical analysis. Findings Results indicate a significant improvement in abrasive wear properties with the incorporation of TiO2 filler. The COF is found to be most influenced by the normal load (55.19%), followed by grit size, wt% TiO2 filler and sliding distance. SWR is found to be most influenced by the grit size (42.92%), followed by wt% TiO2, normal load and sliding distance. Notably, the Taguchi model aligns well with experimental results, demonstrating its efficacy in predicting the abrasive wear behavior of FFRCs. Originality/value This research introduces a novel hybrid composite that combines TiO2 filler and flax fibers, showcasing their potential to enhance the tribological properties of epoxy composites. The study offers valuable insights into optimizing abrasive wear test variables in natural fiber-reinforced composites using Taguchi DOE and ANOVA, crucial for improving the performance of sustainable materials in engineering applications.

Impact of Silica Sand on Mechanical Properties of Epoxy Resin Composites and Their Application in CFRP–Concrete Bonding

Premature debonding between carbon fiber-reinforced polymer (CFRP) and concrete is a critical issue in structural reinforcement applications, often leading to a significant reduction in the load-carrying capacity of the system. This failure mode is typically initiated by inadequate adhesion at the interface, compromising the effectiveness of CFRP in enhancing the structural performance of concrete elements. To address these issues, this study explores the impact of silica sand on the mechanical and adhesion properties of epoxy resin composites. Initially, this paper investigates the physical and mechanical properties of epoxy resin composites by varying the ratios of silica sand from 0% to 15% by volume. Subsequently, it examines the effectiveness of these composites as sealing materials to enhance the bond strength between CFRP and concrete. Incorporating a 10% silica content improves the mechanical properties of the epoxy resin, with the tensile strength increasing from 29.47 MPa to 35.52 MPa and an elastic modulus from 4.38 GPa to 5.83 GPa. Furthermore, silica sand enhances the adhesion strength between CFRP and concrete, as confirmed by the increase in the pull-out force from 14.21 kN to 18.79 kN. Silica particles improve surface roughness and interlocking, contributing to a better load distribution and stress transfer at the interface. Therefore, silica-filled epoxy resin is an efficient material for CFRP–concrete bonding applications.

PENGARUH FRAKSI VOLUME DAN PEMBEBANAN TERHADAP SIFAT FISIK DAN MEKANIK KOMPOSIT BERPENGUAT SERBUK CANGKANG KERANG LOKAN

The increasing consumption of local clam shells which contain high nutritional value in society has resulted in an increase in waste sea shells in areas around the coast of Bengkulu Province. The high calcium content in lokan clam shells attracts researchers to study the physical and mechanical properties of epoxy resin composites reinforced lokan clam shell powder. This research aims to investigate the effect of variations in the volume fraction of lokan clam shell powder and the mold loading on the physical and mechanical properties of composites reinforced lokan clam shell powder. The process of manufacturing shell powder is carried out by heating at a temperature of 900oC for 6 hours. Variations in the volume fraction of lokan clam shell powder consist of 30, 50, 70%. Meanwhile, the mold loading was varied by 0, 500 N, and 1 kN. The manufacturing process uses hand lay-up techniques. Physical and mechanical tests on composites include water absorption tests, density, tensile tests and impact tests. The results of the research show that the powder volume fraction and mold loading influence the physical and mechanical properties of composites reinforced lokan clam shell powder. The best physical properties of composite were obtained at a powder volume fraction of 70% and a mold loading of 1 kN, namely with a density of 1.43 g/cm3. The best mechanical properties of composite were obtained at a volume fraction of 30% and a mold loading of 1 kN, namely with a tensile strength of 33.2 MPa and an impact toughness of 366.8 kJ/m2.

Improving interfacial and mechanical properties of epoxy resin composites by chemical grafting modification of poly‐ether‐ether‐ketone microparticles with carbon nanotubes

AbstractThe research on epoxy resin toughening is of great significance for its application in aerospace, automotive industries, marine vessels, and other fields. Poly‐ether‐ether‐ketone (PEEK) and carbon nanotubes (CNTs) are ideal candidates for epoxy reinforcement in thermoplastic materials and nanomaterials, respectively. In this study, CNTs were first chemically grafted onto PEEK microparticles using an amidation reaction. These modified hybrid materials were then utilized as fillers in epoxy composites to enhance their strength and toughness. The changes in sample structure, composition, thermal properties, and wettability during the chemical grafting process between CNTs and PEEK were systematically studied. In comparison to pure PEEK, the surface energy of CNTs‐PEEK hybrid materials increased by 11.58% due to CNTs grafting, resulting in improved wettability and enhanced interface bonding between PEEK and the epoxy matrix. Concurrently, the CNTs‐PEEK/epoxy composites exhibited significant enhancements, with the highest tensile strength, tensile elongation at break, flexural strength, and flexural modulus increased by 31.00%, 30.84%, 121.43%, and 23.22%, respectively. The positive reinforcement effect of modified CNTs‐PEEK fillers in epoxy composites and the exploration of CNTs grafting onto PEEK extend the potential applications of epoxy composites.Highlights CNTs were bonded to PEEK via an amidation reaction by the chemical grafting method. CNTs‐PEEK have an 11.58% increase in surface energy compared to pure PEEK. CNTs‐PEEK/epoxy composites showed improved mechanical properties. The enhancement mechanisms of CNTs‐PEEK/epoxy composites were analyzed.

Influence of curing agent modified BN with different molecular structures on the heat conduction and electrical insulation property of epoxy composites

AbstractBoron nitride (hBN) serves as an outstanding high‐performance polymer organic filler. However, its hexagonal crystal structure renders it chemically inert, thus limiting its applications. This study proposes the modification of hBN using economical amine and anhydride curing agents to reduce aggregation and enhance the heat conduction of epoxy resin. Specifically, the DETA curing agent and methyl tetrahydrophthalic anhydride (MTHPA) curing agent were grafted onto the hBN surface via ball milling and eco‐friendly water scrubbing processes. Subsequently, the modified functionalized BNNS were uniformly dispersed in epoxy resin via a wet process to form composite materials. Results indicate that both modified fillers maintain good dispersion at the epoxy interface. Compared to epoxy resin, the heat conduction of the EP/MTHPA‐BNNS composite material with 10 vol% loading increased by 212%. The EP/DETA‐BNNS composite exhibited a relative thermal conductivity enhancement of 191%. Moreover, both of materials demonstrated significantly improved thermal stability, with slightly reduced breakdown strength. Mechanical property testing revealed a maximum increase of 187.5% in fracture elongation.Highlights Comprehensive study on curing agent modified hBN High dispersion of BNNS after wet ball milling Modified BNNS improves composite interface properties The thermal conductivity increases twice under 10 wt% BNNS loading Composite materials with outstanding electrical insulation and high fracture elongation

Enhanced breakdown strength of epoxy composites by constructing dual-interface charge barriers at the micron filler/epoxy matrix interface

For the advanced energy systems with ultra-high voltage and frequency, in order to improve the thermal conductivity, arc resistance and mechanical strength of epoxy-based dielectric materials, the addition of micron inorganic fillers is necessary. However, this will inevitably degrade their breakdown strength. In this work, the example of constructing dual-interface charge barriers by optimizing molecular structure at micron filler/epoxy matrix interface to capture charge and then enhance the breakdown strength of epoxy composites is reported. Results show that the Al2O3@PVDF-6/BPA system with optimized interfacial structure exhibits the breakdown strength of AC and DC voltages of 37.5 and 67.8 kV/mm, respectively, far outperforming current epoxy composites containing micron fillers. The charge trapping effects in the dual-interface charge barriers are comprehensively investigated, which is confirmed to be the reason for the improved breakdown strength. In particular, the construction of dual-interface charge barriers hardly sacrifices the thermal and mechanical properties of epoxy composites. This work unveils a scalable approach to exploring satisfied dielectric epoxy composites by dual-interface charge barriers construction at the micron filler/epoxy matrix interface.

The Study of Composite Materials Properties Based on Polymers and Nano-Additives from Industrial Wastes from Kazakhstan.

This research is aimed at studying the properties of polymer anticorrosion coatings based on ED-20 resin widely used in practice and industrial wastes. In this work, three basic types of nanoscale nanofillers were chosen: dispersed particles-microsilica, microspheres obtained at Kazakh enterprises, and carbon nanotubes. Physicochemical research methods were used in the research: a laser analyzer for studying the dispersibility of industrial waste and spectrometric research methods. The properties of materials were investigated by standardized methods. The obtained results show that the introduction of microsilica and microspheres obtained at Kazakhstani enterprises, used as additives, improves both the physical and mechanical properties of epoxy composites compared to the standard (control) material. The results of experiments have shown that the optimal content of additives of microsilica and microspheres provides an improvement in the physical and mechanical properties of epoxy composites in comparison with the standard (control) material. Studies have shown that the introduction of microspheres into ED-20 polymer increases impact toughness. The introduction of microsilica into the matrix contributes to the increase of elastic modulus. Experimental studies of optical properties of samples of carbon composite polymer films based on polystyrene (PS) with additives of carbon nanotubes C60 and C70 and multilayer carbon nanotubes were also carried out. The experimental results obtained for the optical properties of polymer composites based on basic polymers from solid waste and carbon nanotubes showed that the optical properties of polymer composites undergo noticeable changes.

Effects of dopamine‐modified ZnO and Ce‐Zr oxides on UV resistance and thermal stability of epoxy composites

AbstractIn this work, surface‐modified Ce‐Zr oxides and ZnO nanoparticles were conveniently prepared by dopamine (Dpa) treatment and then composited with epoxy (EP) by hot pressing. Thermogravimetric analysis (TGA) and UV‐shielding properties of the EP composites with surface modification with Dpa‐CZ and Dpa‐ZnO were measured. The TGA results showed that the modified treated fillers had no loss of heat resistance of the matrix and had an enhancement effect on the initial and maximum decomposition temperatures. In addition, the UV‐shielding properties of EP composites after Dpa‐CZ and Dpa‐ZnO modifications both showed a significant enhancement effect compared to pure EP. The T(UVA) of the 0.5 wt% Dpa‐ZnO modified composite decreased to less than 0.017%, and the T(UVB) decreased to less than 0.0059%. The T(UVA) of the 0.5 wt% Dpa‐CZ modified composite decreased to less than 15.98%, and the T(UVB) decreased to below 1.14%. The composites have both excellent thermal stability and UV‐shielding efficiency.

The effects of the contents of modified‐diatomite on the properties of modified‐diatomite/epoxy resin composites

AbstractExternal plasticization is one of the effective ways to toughen epoxy resins. In this study, an inorganic filler (EMD) was prepared by chemical modification of diatomite and was used to fill epoxy resin matrix. The effects of different amounts (5%, 10%, 15%, and 20%) of raw diatomite (RD) and modified‐diatomite (EMD) on the mechanical and thermal properties of epoxy resin composites were studied. The mechanical results showed that the impact strength, tensile strength, and bending strength of EMD/EP were higher than those of RD/EP. The impact strength of EMD‐15/EP reached 5.39 KJ/m2, which was 36.8% higher than that of RD‐15/EP. Thermogravimetric analysis showed that the thermal stability of EMD/EP was better than that of RD/EP. The results of DMA show that the glass transition temperature of EMD/EP was lower than that of RD/EP. Non‐isothermal differential scanning calorimetry study showed that the apparent activation energy of EMD‐15/EP was much lower than that of RD‐15/EP, which proved that EMD could promote the curing of epoxy resin. The Malek method was used to determine that both the RD‐15/EP and EMD‐15/EP curing systems were autocatalytic (Šesták–Berggren) models.