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Zhang Y, Yan S, Wang X, Guan Y, Du C, Fan T, Li H, Zhai J. An Experimental Investigation of the Mechanism of Hygrothermal Aging and Low-Velocity Impact Performance of Resin Matrix Composites. Polymers (Basel) 2024; 16:1477. [PMID: 38891424 PMCID: PMC11174897 DOI: 10.3390/polym16111477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 06/21/2024] Open
Abstract
Resin matrix composites (RCs) have better thermal and chemical stability, so they are widely used in engineering fields. In this study, the aging process and mechanism of two different types of resin-based three-dimensional four-way braided composites (H15 and S15) under different hygrothermal aging conditions were studied. The effect of aging behavior on the mechanical properties of RCs was also studied. Three different aging conditions were studied: Case I, 40 °C Soak; Case II, 70 °C Soak; and Case III, 70 °C-85% relative humidity (RH). It was found that the hygroscopic behavior of RCs in the process of moisture-heat aging conforms to Fick's second law. Higher temperatures and humidity lead to higher water absorption. The equilibrium hygroscopic content of H15 was 1.46% (Case II), and that of S15 was 2.51% (Case II). FT-IR revealed the different hygroscopic mechanisms of H15 and S15 in terms of aging behavior. On the whole, the infiltration behavior of water molecules is mainly exhibited in the process of wet and thermal aging. At the same time, the effect of the aging process on resin matrices was observed using SEM. It was found that the aging process led to the formation of microchannels on the substrate surface of S15, and the formation of these channels was the main reason for the better moisture absorption and lower mechanical strength of S15. At the same time, this study further found that temperature and oxygen content are the core influences on post-aging strength. The LVI experiment also showed that the structural changes and deterioration effects occurring after aging reduced the strength of the studied material.
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Affiliation(s)
- Yuxuan Zhang
- Department of Engineering Mechanics, Harbin University of Science and Technology, Harbin 150000, China; (Y.Z.); (X.W.); (Y.G.); (C.D.)
| | - Shi Yan
- Department of Engineering Mechanics, Harbin University of Science and Technology, Harbin 150000, China; (Y.Z.); (X.W.); (Y.G.); (C.D.)
| | - Xin Wang
- Department of Engineering Mechanics, Harbin University of Science and Technology, Harbin 150000, China; (Y.Z.); (X.W.); (Y.G.); (C.D.)
| | - Yue Guan
- Department of Engineering Mechanics, Harbin University of Science and Technology, Harbin 150000, China; (Y.Z.); (X.W.); (Y.G.); (C.D.)
| | - Changmei Du
- Department of Engineering Mechanics, Harbin University of Science and Technology, Harbin 150000, China; (Y.Z.); (X.W.); (Y.G.); (C.D.)
| | - Tiancong Fan
- Aulin College, Northeast Forestry University, Harbin 150000, China;
| | - Hanhua Li
- Department of Engineering Mechanics, Beijing Institute of Astronautical Systems Engineering, Beijing 100076, China;
| | - Junjun Zhai
- College of Aeronautics and Astronautics, North China Institute of Aerospace Engineering, Langfang 065000, China;
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2
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Liu Y, Gao J, Guo N, Sun J, Hu H, Chi X. Nonlinear Conductivity and Thermal Stability of Anti-Corona Epoxy Resin Nanocomposites. Polymers (Basel) 2024; 16:1296. [PMID: 38732765 PMCID: PMC11085125 DOI: 10.3390/polym16091296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/28/2024] [Accepted: 05/01/2024] [Indexed: 05/13/2024] Open
Abstract
The long-term operation of motors induces substantial alterations in the surface conductivity and nonlinear coefficient of anti-corona paint, diminishing its efficacy and jeopardizing the longevity of large motors. Hence, the development of high-performance anti-corona paint holds paramount importance in ensuring motor safety. In this study, we integrate two nano-fillers, namely silicon carbide (SiC) and organic montmorillonite (O-MMT), into a composite matrix comprising micron silicon carbide and epoxy resin (SiC/EP). Subsequently, three distinct types of anti-corona paint are formulated: SiC/EP, Nano-SiC/EP, and O-MMT/SiC/EP. Remarkably, O-MMT/SiC/EP exhibits a glass transition temperature about 25 °C higher than that of SiC/EP, underscoring its superior thermal properties. Moreover, the introduction of nano-fillers markedly augments the surface conductivity of the anti-corona paint. Aging tests, conducted across varying temperatures, unveil a notable reduction in the fluctuation range of surface conductivity post-aging. Initially, the nonlinear coefficients exhibit a declining trend, succeeded by an ascending trajectory. The O-MMT/SiC/EP composite displays a maximum nonlinearity coefficient of 1.465 and a minimum of 1.382. Furthermore, the incorporation of nanofillers amplifies the dielectric thermal stability of epoxy resin composites, with O-MMT/SiC/EP showcasing the pinnacle of thermal endurance. Overall, our findings elucidate the efficacy of nano-fillers in enhancing the performance and longevity of anti-corona paint, particularly highlighting the exceptional attributes of the O-MMT/SiC/EP composite in bolstering motor safety through improved thermal stability and electrical properties.
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Affiliation(s)
- Yanli Liu
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, College of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China; (Y.L.); (N.G.); (J.S.); (H.H.)
| | - Junguo Gao
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, College of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China; (Y.L.); (N.G.); (J.S.); (H.H.)
| | - Ning Guo
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, College of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China; (Y.L.); (N.G.); (J.S.); (H.H.)
| | - Jiaming Sun
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, College of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China; (Y.L.); (N.G.); (J.S.); (H.H.)
| | - Haitao Hu
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, College of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin 150080, China; (Y.L.); (N.G.); (J.S.); (H.H.)
| | - Xiaohong Chi
- State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi’an Jiaotong University, Xi’an 710000, China;
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3
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Mishnev M, Korolev A, Zadorin A. Effect of Thermal Aging on Viscoelastic Behavior of Thermosetting Polymers under Mechanical and Cyclic Temperature Impact. Polymers (Basel) 2024; 16:391. [PMID: 38337279 DOI: 10.3390/polym16030391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 01/13/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
Development of load-bearing fiber reinforced plastic (hereinafter referred to as FRP) composite structures in civil engineering, exploited under high temperatures, such as industrial chimneys and gas ducts, requires the knowledge of their long-term behavior under constant and cyclic mechanical and temperature loads. Such conditions mean that the viscoelasticity of FRP should be considered along with the thermal aging effect. This research is devoted to the effects of thermal aging on the viscoelastic behavior of polymers. Two sets of experiments were conducted: creep tensile tests and cyclic heating in a constrained state. The Kelvin-Voigt viscoelasticity model was used to determine the rheological parameters of binder from experimental creep curves. Cyclic heating was used to compare the behavior of normal and thermally aged binders and to evaluate the possibility of temperature stress accumulation. Fourier-transform infrared spectroscopy was used for polymer's structural changes investigation. Both tests showed that non-aged glassed polymer (hereinafter referred to as GP) was prone to viscoelastic behavior, while the thermally aged GP lost viscosity and worked almost perfectly elastic. It was assumed that long heat treatment had caused changes in the inner structure of the GP, reducing the number of weak bonds and increasing the number of elastic ones. Therefore, the results show that the designing of FRP structures, exploited under thermomechanical load, requires using the elastic model while taking into account the properties of FRP after long-term heat treatment.
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Affiliation(s)
- Maxim Mishnev
- Department of Building Construction and Structures, South Ural State University, Chelyabinsk 454080, Russia
| | - Alexander Korolev
- Department of Building Construction and Structures, South Ural State University, Chelyabinsk 454080, Russia
| | - Alexander Zadorin
- Department of Building Construction and Structures, South Ural State University, Chelyabinsk 454080, Russia
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Medri V, Natali Murri A, Papa E, Mingazzini C, Scafè M, Landi E. Ultra-High-Temperature Ceramic-Doped Inorganic Polymers for Thermo-Structural Fiber-Reinforced Composites. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6649. [PMID: 37895632 PMCID: PMC10608054 DOI: 10.3390/ma16206649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 09/29/2023] [Accepted: 10/07/2023] [Indexed: 10/29/2023]
Abstract
New inorganic nanostructured matrices for fiber-reinforced composites with enhanced high-temperature stability were developed from alkali aluminosilicate polymers doped with different ultra-high-temperature ceramic (UHTC) particles. The alkali aluminosilicate matrices were synthesized at room temperature with a high SiO2:Al2O3 ratio and then further functionalized by doping with 4-5 wt % of micrometric SiC, ZrB2, ZrC, and HfC powders and finally thermally stabilized as glass-ceramics at 750 °C. The different UHTC-doped matrices were characterized according to their dimensional and microstructural changes after thermal cycling in air flux at 1000 °C. The first results showed that carbide-based UHTC powders improved the thermal stability of the matrices, preventing the excessive swelling of the material and the formation of detrimental voids that might result in the lack of adhesion with reinforcing fibers. Contrarily, the addition of ZrB2 resulted in an excessive matrix swelling at high temperature, thus proving no efficacy compared to the undoped matrix. Impregnation tests carried out on C-fiber fabrics showed good processability, adhesion to the fibers, and fracture pull-out, especially for carbide-based matrices.
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Affiliation(s)
- Valentina Medri
- National Research Council, Institute of Science, Technology and Sustainability for Ceramics (CNR-ISSMC), Via Granarolo 64, 48018 Faenza, Italy; (V.M.); (E.P.); (E.L.)
| | - Annalisa Natali Murri
- National Research Council, Institute of Science, Technology and Sustainability for Ceramics (CNR-ISSMC), Via Granarolo 64, 48018 Faenza, Italy; (V.M.); (E.P.); (E.L.)
| | - Elettra Papa
- National Research Council, Institute of Science, Technology and Sustainability for Ceramics (CNR-ISSMC), Via Granarolo 64, 48018 Faenza, Italy; (V.M.); (E.P.); (E.L.)
| | - Claudio Mingazzini
- SSPT-PROMAS-TEMAF, ENEA, Via Ravegnana 186, SP302, 48018 Faenza, Italy; (C.M.); (M.S.)
| | - Matteo Scafè
- SSPT-PROMAS-TEMAF, ENEA, Via Ravegnana 186, SP302, 48018 Faenza, Italy; (C.M.); (M.S.)
| | - Elena Landi
- National Research Council, Institute of Science, Technology and Sustainability for Ceramics (CNR-ISSMC), Via Granarolo 64, 48018 Faenza, Italy; (V.M.); (E.P.); (E.L.)
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5
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Wang T, Razaqpur AG, Chen S. Durability of GFRP and CFRP Bars in the Pore Solution of Calcium Sulfoaluminate Cement Concrete Made with Fresh or Seawater. Polymers (Basel) 2023; 15:3306. [PMID: 37571199 PMCID: PMC10422602 DOI: 10.3390/polym15153306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023] Open
Abstract
Calcium sulfoaluminate cement concrete (CSAC) reinforced by fiber-reinforced polymer (FRP) bars, termed bars for brevity, is a good alternative to steel-reinforced concrete in marine environments due to the corrosion resistance of FRP and the lower pH of CSAC. For the first time, multi-mechanical tests are conducted to compare the durability of glass FRP (GFRP) to that of carbon FRP (CFRP) after exposure to CSAC pore solution. The bars were immersed in a simulated pore solution of CSAC made with either fresh water and river sand or with seawater and sea sand. Solution temperature was held constant at 30 °C, 45 °C or 60 °C for 30, 60, 90 and 180 days of immersion. Tensile, horizontal and transverse shear tests, as well as detailed microstructural analyses, were conducted to determine the level and mechanisms of degradation for each type of bar. Sea salt increases the degradation of both bars, but it degrades GFRP more than CFRP. The bars' retained tensile strength is a reliable indicator of their durability, while their post-exposure horizontal and transverse shear strengths are found inconsistent and counter intuitive. In the GFRP, the fiber, the epoxy matrix and their interface suffered damage, but in the CFRP, the carbon fiber was not damaged. Under the test conditions in this study, the maximum reduction in the tensile strength of the GFRP was 56.9% while that of CFRP was 15.1%. Based on the relevant ASTM standard, the CFRP bar satisfies the alkaline resistance requirement of the standard in the CSAC pore solution with and without salt, whereas the GFRP bar does not meet the same requirement in the above pore solution with salt.
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Affiliation(s)
- Tuanjie Wang
- Sino-Canada Joint R&D Centre on Water and Environmental Safety, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; (T.W.); (S.C.)
- College of Civil Engineering, Zhengzhou University of Industrial Technology, Zhengzhou 451150, China
| | - Abdul Ghani Razaqpur
- Sino-Canada Joint R&D Centre on Water and Environmental Safety, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; (T.W.); (S.C.)
- Department of Civil Engineering, McMaster University, Hamilton, ON L8S 4L7, Canada
| | - Shaoliang Chen
- Sino-Canada Joint R&D Centre on Water and Environmental Safety, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; (T.W.); (S.C.)
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6
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Saitta L, Rizzo G, Tosto C, Cicala G, Blanco I, Pergolizzi E, Ciobanu R, Recca G. Chemical Recycling of Fully Recyclable Bio-Epoxy Matrices and Reuse Strategies: A Cradle-to-Cradle Approach. Polymers (Basel) 2023; 15:2809. [PMID: 37447455 DOI: 10.3390/polym15132809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 07/15/2023] Open
Abstract
Currently, the epoxy resin market is expressing concerns about epoxy resins' non-recyclability, which can hinder their widespread use. Moreover, epoxy monomers are synthesized via petroleum-based raw materials, which also limits their use. So, it is crucial to find more environmentally friendly alternative solution for their formulation. Within this context, the aim of this paper is to exploit a Cradle-to-Cradle approach, which consists of remodeling and reshaping the productive cycle of consumer products to make sure that they can be infinitely reused rather than just being recycled with a downgrading of their properties or uses, according to the principle of the complete circular economy. Indeed, after starting with a fully-recyclable bio-based epoxy formulation and assessing its recyclability as having a process yield of 99%, we obtained a recycled polymer that could be reused, mixing with the same bio-based epoxy formulation with percentages varying from 15 wt% to 27 wt%. The formulation obtained was thoroughly characterized by a dynamic-mechanical analysis, differential scanning calorimetry, and flexural tests. This approach had two advantages: (1) it represented a sustainable disposal route for the epoxy resin, with nearly all the epoxy resin recovered, and (2) the obtained recycled polymer could be used as a green component of the primary bio-based epoxy matrix. In the end, by using replicated general factorial designs (as statistical tools) combined with a proper optimization process, after carrying out a complete thermo-mechanical characterization of the developed epoxy formulations, the right percentage of recycled polymer content was selected with the aim of identifying the most performing epoxy matrix formulation in terms of its thermo-mechanical properties.
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Affiliation(s)
- Lorena Saitta
- Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy
| | - Giuliana Rizzo
- Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy
| | - Claudio Tosto
- Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy
| | - Gianluca Cicala
- Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy
- INSTM-UDR CT, Viale Andrea Doria 6, 95125 Catania, Italy
| | - Ignazio Blanco
- Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy
| | - Eugenio Pergolizzi
- Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy
| | - Romeo Ciobanu
- Electrical Engineering Faculty, Gheorghe Asachi Technical University of Iasi, Dimitrie Mangeron Bd. 67, 700050 Iasi, Romania
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7
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Lan Z, Deng J, Xu Z, Ye Z, Nie Y. Study of Heat Treatment Effect on Mechanical Properties of Epoxy Resin Reinforced with Fiber Glass. Polymers (Basel) 2023; 15:2734. [PMID: 37376380 DOI: 10.3390/polym15122734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/12/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
In this paper, mechanical properties of the diglycidyl ether of bisphenol A epoxy resin (EP) reinforced with a 20% fiber glass (GF) with layered structure after high temperature aging are studied. Tensile and flexural stress-strain curves of the GF/EP composite after aging tests in the temperature range of 85-145 °C in air were measured. Tensile and flexural strength demonstrate gradual decrease with the increase in the aging temperature. The failure mechanism at the micro scale is studied by the scanning electron microscopy. A separation of the GFs and EP matrix and evident pullout of the GFs are observed. Degradation of the mechanical properties is explained by a cross-linking and chain scission of the initial molecular structure of the composite and decrease in the interfacial adhesion force between GFs and EP matrix caused by oxidation of the EP matrix and difference of the GF and EP coefficients of thermal expansion.
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Affiliation(s)
- Zhenbo Lan
- Wuhan Nari Limited Liability Company of State Grid Electric Power Research Institute, Wuhan 430000, China
- State Grid Electric Power Research Institute, Nanjing 210000, China
| | - Jiangang Deng
- Wuhan Nari Limited Liability Company of State Grid Electric Power Research Institute, Wuhan 430000, China
- State Grid Electric Power Research Institute, Nanjing 210000, China
| | - Zhuolin Xu
- Wuhan Nari Limited Liability Company of State Grid Electric Power Research Institute, Wuhan 430000, China
- State Grid Electric Power Research Institute, Nanjing 210000, China
| | - Zhu Ye
- Wuhan Nari Limited Liability Company of State Grid Electric Power Research Institute, Wuhan 430000, China
- State Grid Electric Power Research Institute, Nanjing 210000, China
| | - Yu Nie
- Wuhan Nari Limited Liability Company of State Grid Electric Power Research Institute, Wuhan 430000, China
- State Grid Electric Power Research Institute, Nanjing 210000, China
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Borah N, Karak N. Green composites of bio-based epoxy and waste tea fiber as environmentally friendly structural materials. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2023. [DOI: 10.1080/10601325.2023.2177171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Affiliation(s)
- Nobomi Borah
- Advanced Polymer and Nanomaterial Laboratory (APNL), Department of Chemical Sciences, Tezpur University, Napam, Tezpur, Assam, India
| | - Niranjan Karak
- Advanced Polymer and Nanomaterial Laboratory (APNL), Department of Chemical Sciences, Tezpur University, Napam, Tezpur, Assam, India
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Akibul Islam M, Asaduzzaman Chowdhury M, Arefin Kowser M, Osman Ali M, Azad K, Ramjan Ali M. Enhancement of Thermal Properties of Kevlar 29 Coated by SiC and TiO2 Nanoparticles and their Binding Energy Analysis. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2022.103959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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10
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Effect of Long-Term Thermal Relaxation of Epoxy Binder on Thermoelasticity of Fiberglass Plastics: Multiscale Modeling and Experiments. Polymers (Basel) 2022; 14:polym14091712. [PMID: 35566881 PMCID: PMC9102714 DOI: 10.3390/polym14091712] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 04/18/2022] [Accepted: 04/20/2022] [Indexed: 02/04/2023] Open
Abstract
The work is devoted to the prediction and experimental research of the elastic bending modulus of glass-reinforced plastics with an epoxy matrix on anhydride hardener reinforced with different glass fabrics. Experimental studies have been carried out to assess the effect of thermal relaxation of the polymer matrix structure due to long-term exposure to elevated temperatures (above the glass transition temperature of the polymer matrix) on the GRP elastic bending modulus at temperatures ranging from 25 to 180 °C. It has been shown that due to the thermal relaxation of the polymer matrix structure, the GRP modulus increases significantly at temperatures above 110 °C and decreases slightly at lower temperatures. Using a multiscale simulation based on a combination of the finite-element homogenization method in the Material Designer module of the ANSYS software package and three-point bending simulation in the ANSYS APDL module, the elastic modulus of FRP was predicted concerning the temperature, its averaged structural properties, and thermal relaxation of the polymer matrix structure. We have also carried out the prediction of the temperature dependences of the modulus of elasticity of glass-reinforced plastics on different types of glass fabrics in the range from 25 to 200 °C by using the entropic approach and the layered model.
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Hygrothermal Damage Monitoring of Composite Adhesive Joint Using the Full Spectral Response of Fiber Bragg Grating Sensors. Polymers (Basel) 2022; 14:polym14030368. [PMID: 35160357 PMCID: PMC8840299 DOI: 10.3390/polym14030368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 01/07/2022] [Accepted: 01/12/2022] [Indexed: 02/01/2023] Open
Abstract
Adhesive joints in composite structures are subject to degradation by elevated temperature and moisture. Moisture absorption leads to swelling, plasticization, weakening of the interface, interfacial defects/cracking and reduction in strength. Moisture and material degradation before the formation of defects are not readily revealed by conventional non-destructive examination techniques. Embedded fiber Bragg grating (FBG) sensors can reflect the swelling strain in adhesive joints and offer an economical alternative for on-line monitoring of moisture absorption under hygrothermal aging. Most of the available works relied on the peak shifting phenomenon for sensing. Degradation of adhesive and interfacial defects will lead to non-uniform strain that may chirp the FBG spectrum, causing complications in the peak shifting measurement. It is reasoned that the full spectral responses may be more revealing regarding the joint's integrity. Studies on this aspect are still lacking. In this work, single-lap joint composite specimens with embedded FBGs are soaked in 60 °C water for 30 days. Spectrum evolution during this period and subsequent tensile and fatigue failure has been studied to shed some light on the possible use of the full spectral response to monitor the development of hygrothermal degradation.
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12
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Idrisi AH, Mourad AHI, Abdel-Magid BM, Shivamurty B. Investigation on the Durability of E-Glass/Epoxy Composite Exposed to Seawater at Elevated Temperature. Polymers (Basel) 2021; 13:polym13132182. [PMID: 34209208 PMCID: PMC8271432 DOI: 10.3390/polym13132182] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 06/26/2021] [Accepted: 06/27/2021] [Indexed: 11/16/2022] Open
Abstract
In this manuscript, the durability of the E-glass/epoxy composite was determined under a seawater environment. The effect of harsh environment was investigated in terms of seawater absorption, microstructure and degradation in mechanical properties. E-glass epoxy composite specimens were conditioned in gulf seawater at 23 °C, 65 °C and 90 °C for the period of 12 months. It was observed that the mass of the samples increased after the immersion of 12 months at 23 °C and 65 °C whereas it reduced at 90 °C. The salt deposition was observed at the surface of specimens without any crack for the seawater conditioning at 23 °C and 65 °C. The swelling and crack formation were significantly visible on the surface of the specimen immersed for 12 months at 90 °C. It indicates that the degradation mechanism accelerated at elevated temperature results fiber/matrix debonding. The tensile test indicates slight variation in the elastic modulus and reduction in strength of E-glass epoxy composite by 1% and 9% for specimens immersed at 23 °C and 65 °C respectively. However, at 90 °C, the tensile strength sharply decreased to 7% and elastic modulus significantly increased in the exposure of 12 months. A prediction approach based on a time-shift factor (TSF) was used. This model predicted that the strength retention of E-glass/Epoxy composite will be reduced to 7% in 450 years after immersion in seawater at 23 °C. Lastly, the activation energy for the degradation of the composite was calculated.
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Affiliation(s)
- Amir Hussain Idrisi
- Department of Mechanical Engineering, United Arab Emirates University, Al Ain 15551, United Arab Emirates;
| | - Abdel-Hamid I. Mourad
- Department of Mechanical Engineering, United Arab Emirates University, Al Ain 15551, United Arab Emirates;
- National Water and Energy Center, United Arab Emirates University, Al Ain 15551, United Arab Emirates
- Mechanical Design Department, Faculty of Engineering, Helwan University, Cairo 11795, Egypt
- Correspondence:
| | - Beckry M. Abdel-Magid
- Department of Composite Materials Engineering, Winona State University, Winona, MN 5598, USA;
| | - B. Shivamurty
- Department of Mechanical and Manufacturing Engineering, Manipal Institute of Technology, Manipal 572104, India;
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Effect of Immersion in Water or Alkali Solution on the Structures and Properties of Epoxy Resin. Polymers (Basel) 2021; 13:polym13121902. [PMID: 34201026 PMCID: PMC8228582 DOI: 10.3390/polym13121902] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/26/2021] [Accepted: 06/01/2021] [Indexed: 11/26/2022] Open
Abstract
The durability of fiber-reinforced polymer (FRP) composites is significantly dependent on the structures and properties of the resin matrix. In the present paper, the effects of physical or chemical interactions between the molecular chain of the epoxy resin matrix and water molecules or alkaline groups on the water absorption, mechanical structures, and microstructures of epoxy resin samples were studied experimentally. The results showed that the water uptake curves of the epoxy resin immersed in water and an alkali solution over time presented a three-stage variation. At different immersion stages, the water uptake behavior of the resin showed unique characteristics owing to the coupling effects of the solution concentration gradient diffusion, molecular hydrolysis reaction, and molecular segment movement. In comparison with the water immersion, the alkali solution environment promoted the hydrolysis reaction of the epoxy resin molecular chain. After the immersion in water or the alkali solution for one month, the water uptake of the resin was close to saturate, and the viscoelasticity was observed to decrease significantly. The micropore and free volume space on the surface and in the interior of the resin gradually increased, while the original large-scale free volume space decreased. The tensile strength decreased to the lowest point after the immersion in water and the alkali solution for one month, and the decrease percentages at 20 °C and 60 °C water or 60 °C alkali solution were 24%, 28%, and 22%, respectively. Afterward, the tensile strength recovered with the further extension of immersion time. In addition, it can be found that the effect of the alkali solution and water on the tensile strength of the epoxy resin was basically the same.
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Liu T, Hao C, Shao L, Kuang W, Cosimbescu L, Simmons KL, Zhang J. Carbon Fiber Reinforced Epoxy Vitrimer: Robust Mechanical Performance and Facile Hydrothermal Decomposition in Pure Water. Macromol Rapid Commun 2020; 42:e2000458. [PMID: 33230871 DOI: 10.1002/marc.202000458] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/09/2020] [Indexed: 11/09/2022]
Abstract
Conventional carbon fiber reinforced thermosetting polymers (CFRPs) are neither recyclable nor repairable due to their crosslinked network. The rapid growing CFRP market raises a serious concern of the waste management. In this work, a viable method to develop a readily recyclable CFRP based on epoxy vitrimer is introduced. First, a self-catalytic epoxy prepolymer with built-in hydroxy and tertiary amine groups is designed, which upon reaction with an anhydride formed a catalyst-free epoxy vitrimer. The epoxy prepolymer is synthesized from a diamine and an excess of bisphenol A epoxy resin. The hydroxyls and tertiary amines of the epoxy prepolymer efficiently catalyze both curing and the dynamic transesterification of the crosslinked polymer without the need of a catalyst. Then, the epoxy vitrimer is used as the matrix resin to prepare CFRP. The resulting CFRP exhibited a tensile strength as high as 356 MPa. More interestingly, the matrix of the CFRP is efficiently degraded in pure water at above 160 °C. This is because the built-in tertiary amines catalyze the hydrolysis of the ester bonds of the crosslinked network. The simple method developed in this work provides a framework for the development of recyclable CFRP.
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Affiliation(s)
- Tuan Liu
- School of Mechanical and Materials Engineering, Composite Materials and Engineering Center, Washington State University, Pullman, WA, 99164, USA
| | - Cheng Hao
- School of Mechanical and Materials Engineering, Composite Materials and Engineering Center, Washington State University, Pullman, WA, 99164, USA
| | - Lin Shao
- School of Mechanical and Materials Engineering, Composite Materials and Engineering Center, Washington State University, Pullman, WA, 99164, USA
| | - Wenbin Kuang
- Pacific Northwest National Laboratory, Energy Materials and Processing Division, Energy and Environment Directorate, P.O. Box 999, MSIN K2-44, Richland, WA, 99354, USA
| | - Lelia Cosimbescu
- Pacific Northwest National Laboratory, Energy Materials and Processing Division, Energy and Environment Directorate, P.O. Box 999, MSIN K2-44, Richland, WA, 99354, USA
| | - Kevin L Simmons
- Pacific Northwest National Laboratory, Energy Materials and Processing Division, Energy and Environment Directorate, P.O. Box 999, MSIN K2-44, Richland, WA, 99354, USA
| | - Jinwen Zhang
- School of Mechanical and Materials Engineering, Composite Materials and Engineering Center, Washington State University, Pullman, WA, 99164, USA.,Pacific Northwest National Laboratory, Energy Materials and Processing Division, Energy and Environment Directorate, P.O. Box 999, MSIN K2-44, Richland, WA, 99354, USA
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15
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Effect of elevated in-service temperature on the mechanical properties and microstructure of particulate-filled epoxy polymers. Polym Degrad Stab 2019. [DOI: 10.1016/j.polymdegradstab.2019.108994] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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High Temperature Mechanical Response and Failure Analysis of 3D Five-Directional Braided Composites with Different Braiding Angles. MATERIALS 2019; 12:ma12213506. [PMID: 31731528 PMCID: PMC6862636 DOI: 10.3390/ma12213506] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/02/2019] [Accepted: 10/22/2019] [Indexed: 12/05/2022]
Abstract
Three-dimensional (3D) five-directional braided composites are extensively applied in aeronautics and national defense due to their integrity and structural superiorities. In this paper, 3D five-directional braided carbon/epoxy composites were manufactured, and the high temperature mechanical response and failure mechanisms of composites with braiding angles of 21° and 32° were studied. The out-of-plane compression tests of composites with different braiding angles were conducted at temperatures ranging from 25 °C to 180 °C. Then compression stress–strain curves, compression mechanical response, and failure modes of composites at high temperatures were analyzed and compared. The results show that compression stress–strain curves linearly increased at the initial stage and dropped at various degrees at different temperatures for composites with different braiding angles. The temperature and braiding angle were both important parameters affecting out-of-plane compression properties of 3D five-directional braided composites. Mechanical properties decreased with increasing temperature for both 21° and 32° specimens. Moreover, composites with a small braiding angle possessed higher properties at each temperature point. The morphologies manifested that the failures were a symmetric ±45° shear crack for 21° specimens and a thorough 45° shear crack for 32° specimens, and a 45° fracture weakened with increasing temperature.
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Cao Y, Qian X, Liu C, Yang J, Xie K, Zhang C. Controllable preparation of a novel epoxy/anhydride system with polyether - Polyester semi-interpenetrating structure and the excellent hydrothermal aging resistance properties. Polym Degrad Stab 2019. [DOI: 10.1016/j.polymdegradstab.2019.108935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Doblies A, Boll B, Fiedler B. Prediction of Thermal Exposure and Mechanical Behavior of Epoxy Resin Using Artificial Neural Networks and Fourier Transform Infrared Spectroscopy. Polymers (Basel) 2019; 11:E363. [PMID: 30960347 PMCID: PMC6419193 DOI: 10.3390/polym11020363] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 02/08/2019] [Accepted: 02/15/2019] [Indexed: 11/18/2022] Open
Abstract
Thermal degradation detection of cured epoxy resins and composites is currently limited to severe thermal damage in practice. Evaluating the change in mechanical properties after a short-time thermal exposure, as well as estimating the history of thermally degraded polymers, has remained a challenge until now. An approach to accurately predict the mechanical properties, as well as the thermal exposure time and temperature of epoxy resin, using Fourier-transform infrared spectroscopy (FTIR)-spectroscopy, data processing, and artificial neural networks, is presented here. Therefore, an epoxy resin has been fully cured and exposed to elevated temperatures for different time periods. A FTIR-spectrometer was used to measure molecular changes, using mid-IR (MIR)-FTIR for film samples and near-IR (NIR)-FTIR for bulk samples. A quantitative analysis of the thermally degraded film samples shows oxidation, chain-scission, and dehydration in the FTIR spectra in the MIR-range. Using NIR spectroscopy for the bulk samples, only minor changes in the FTIR spectra could be detected. However, using data processing, molecular information was extracted from the NIR range and a degradation model, using an artificial neural network, has been trained. Even though the changes due to thermal exposure were small, the presented model is capable of accurately predicting the time, temperature, and residual strength of the polymer.
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Affiliation(s)
- Audrius Doblies
- Institute of Polymer and Composites, Hamburg University of Technology (TUHH), Denickestr. 15, 20173 Hamburg, Germany.
| | - Benjamin Boll
- Institute of Polymer and Composites, Hamburg University of Technology (TUHH), Denickestr. 15, 20173 Hamburg, Germany.
| | - Bodo Fiedler
- Institute of Polymer and Composites, Hamburg University of Technology (TUHH), Denickestr. 15, 20173 Hamburg, Germany.
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19
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Steinbrück N, Pohl S, Kickelbick G. Platinum free thermally curable siloxanes for optoelectronic application - synthesis and properties. RSC Adv 2019; 9:2205-2216. [PMID: 35516134 PMCID: PMC9059854 DOI: 10.1039/c8ra09801h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 01/05/2019] [Indexed: 11/21/2022] Open
Abstract
Polysiloxanes for applications in the area of optical devices are usually based on two-component platinum catalysed cross-linked materials. Here we report the synthesis and properties of a novel one-component siloxane that can be thermally cured showing similar tailorable properties like commercially available encapsulation systems without using a noble metal catalyst. The pre-curing material is formed by an acid catalysed condensation reaction of trialkoxysilanes (TAS), dialkoxysilanes (DAS) and alkoxy-terminated polysiloxanes. NMR analysis of the formed polymeric compounds reveal that the materials are partially cross-linked gels. The obtained compounds can be thermally cured and consolidated at temperatures between 160 and 200 °C. Depending on the composition a tuneable hardness in between 50–90 Shore A, refractive indices of 1.494–1.505, as well as high temperature stabilities up to 443 °C were obtained. The high thermal- and photostability, the high transparency, as well as the tailorable refractive index makes these materials to ideal systems for optoelectronic applications. Investigations under increased temperatures and high-density illumination reveal that the material can withstand conditions, which are typical for high-performance light emitting diodes (LED). One component thermally curable polysiloxanes with tailorable properties were developed and investigated for their use as LED encapsulation materials.![]()
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Affiliation(s)
- Nils Steinbrück
- Saarland University, Inorganic Solid State Chemistry Campus Building C41 66123 Saarbrücken Germany
| | - Svenja Pohl
- Saarland University, Inorganic Solid State Chemistry Campus Building C41 66123 Saarbrücken Germany
| | - Guido Kickelbick
- Saarland University, Inorganic Solid State Chemistry Campus Building C41 66123 Saarbrücken Germany
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20
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The influence of oxygen on thermal decomposition characteristics of epoxy resins cured by anhydride. Polym Degrad Stab 2018. [DOI: 10.1016/j.polymdegradstab.2018.08.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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21
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Wang Y, Zhou S, Du H, Zhang W. Investigation of the thermal ageing process and mechanism of benzoxazine/bismaleimide/cyanate ester copolymer. HIGH PERFORM POLYM 2018. [DOI: 10.1177/0954008318778894] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Fibre-reinforced polymer (FRP) composites with thermosetting resin matrices are widely used in civil engineering (e.g. pultruded FRP plates and bars), and their thermal ageing behaviour is a concern when they are subjected to elevated temperatures (e.g. FRP chimney). In the present article, the effects of thermal ageing at 200°C and 250°C in air for up to 1000 h on mechanical properties and mechanism of the benzoxazine (Boz), bisphenol A dicyanate cyanate ester (BADCy), and 4,4′-bismaleimidodiphenyl methane (BMI) have been investigated. The effect of time in thermal ageing on structural and mechanical properties of the Boz/BMI/BADCy resin was deeply studied. The moisture absorption increases linearly with the square root of ageing time and it follows Fick’s second law. There are two main categories of reactions in thermal ageing: the first one is the post-curing process, which leads to a larger crosslinking density and a reduced interior stress; while the other is the formation of microcracks and thermal oxidation at the surface of the Boz/BMI/BADCy resin. The combination of the above factors leads to an increase–decrease variation in the mechanical properties. This work is believed to benefit the wide and safe application of a certain Boz/BMI/BADCy resin system in engineering application.
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Affiliation(s)
- Yiqun Wang
- College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu, Sichuan, People’s Republic of China
| | - Shiyi Zhou
- College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu, Sichuan, People’s Republic of China
| | - Haiying Du
- College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu, Sichuan, People’s Republic of China
| | - Wentao Zhang
- College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu, Sichuan, People’s Republic of China
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22
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Steinbrück N, Könemann M, Kickelbick G. Effect of polysiloxane encapsulation material compositions on emission behaviour and stabilities of perylene dyes. RSC Adv 2018; 8:18128-18138. [PMID: 35542110 PMCID: PMC9080585 DOI: 10.1039/c8ra01700j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/05/2018] [Indexed: 11/21/2022] Open
Abstract
Influence of phenyl and methyl group containing polysiloxane encapsulation materials on the fluorescence properties of two perylene diimides.
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Affiliation(s)
- Nils Steinbrück
- Saarland University
- Inorganic Solid State Chemistry
- 66123 Saarbrücken
- Germany
| | | | - Guido Kickelbick
- Saarland University
- Inorganic Solid State Chemistry
- 66123 Saarbrücken
- Germany
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23
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Reuscher V, Haag S, Patzelt G, Mayer B. Aging of anhydride-hardened epoxies in lubricants at elevated temperatures. J Appl Polym Sci 2017. [DOI: 10.1002/app.44877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Vivien Reuscher
- Robert Bosch GmbH; Robert-Bosch-Campus 1 Renningen 71272 Germany
- Faculty for Production Engineering-Mechanical Engineering & Process Engineering; University of Bremen; Badgasteiner Strasse 1 Bremen 28359 Germany
| | - Sabine Haag
- Robert Bosch GmbH; Robert-Bosch-Campus 1 Renningen 71272 Germany
| | - Gesa Patzelt
- Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM); Wiener Strasse 12 Bremen 28359 Germany
| | - Bernd Mayer
- Faculty for Production Engineering-Mechanical Engineering & Process Engineering; University of Bremen; Badgasteiner Strasse 1 Bremen 28359 Germany
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24
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Creep Behavior of Resin Matrix and Basalt Fiber Reinforced Polymer (BFRP) Plate at Elevated Temperatures. JOURNAL OF COMPOSITES SCIENCE 2017. [DOI: 10.3390/jcs1010003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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25
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Pham TD, Vu CM, Choi HJ. Enhanced fracture toughness and mechanical properties of epoxy resin with rice husk-based nano-silica. POLYMER SCIENCE SERIES A 2017. [DOI: 10.1134/s0965545x17030026] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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26
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Guo K, Li P, Zhu Y, Wang F, Qi H. Thermal curing and degradation behaviour of silicon-containing arylacetylene resins. Polym Degrad Stab 2016. [DOI: 10.1016/j.polymdegradstab.2016.07.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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