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Tian S, Ma W, Li H, Wang C, Xia Y, Lan D, Zhou P, Hu D. Assessment of chemical degradation of epoxy resin binder used in the service of the Qin terracotta warriors. Sci Rep 2024; 14:17572. [PMID: 39080048 PMCID: PMC11289444 DOI: 10.1038/s41598-024-68442-3] [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: 03/04/2024] [Accepted: 07/23/2024] [Indexed: 08/02/2024] Open
Abstract
Since the Qin terracotta warriors were unearthed, polyamide 650 cross-linked E-44 epoxy resin binder has been employed to bond and restore them. In this paper, the chemical aging of the binders service in indoor natural environment during the past 30 years in the terracotta warriors was studied by means of infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis. The results indicated that the binders did not emerge the characteristic peak of carbonyl stretching vibration at 1700 cm-1 in the IR spectra of all determined binders, and their thermal decomposition curves did not emerge any abnormal changes, and the thermal decomposition mainly occurred above 300 °C. There are evident ceramic grains attached to the surface of the binders being peeled off for sampling. These results that the binders service in the Qin terracotta warriors did not exhibit an observable chemical aging and still has strong adhesion. Generally, discrepancies were observed between natural aging and accelerated artificial aging due to the ineffectiveness of the latter to reproduce the effects of complex weather conditions. Compared to artificially accelerated aging, the evaluation results in a long-term natural aging of the binder which is used for restoration of the life-size Qin terracotta warriors, providing in the present investigation, are more reliable in terms of predicting the safety of restored terracotta warriors.
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Affiliation(s)
- Siyu Tian
- Engineering Research Center of Historical and Cultural Heritage Protection, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, 710062, China
| | - Wenhua Ma
- Engineering Research Center of Historical and Cultural Heritage Protection, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, 710062, China
| | - Hua Li
- Emperor Qin Shihuang's Mausoleum Site Museum, Lintong, Xi'an, 710600, China
| | - Chunyan Wang
- Emperor Qin Shihuang's Mausoleum Site Museum, Lintong, Xi'an, 710600, China
| | - Yin Xia
- Emperor Qin Shihuang's Mausoleum Site Museum, Lintong, Xi'an, 710600, China
| | - Desheng Lan
- Emperor Qin Shihuang's Mausoleum Site Museum, Lintong, Xi'an, 710600, China
| | - Ping Zhou
- Emperor Qin Shihuang's Mausoleum Site Museum, Lintong, Xi'an, 710600, China.
| | - Daodao Hu
- Engineering Research Center of Historical and Cultural Heritage Protection, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, 710062, China.
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Wesgate R, Bentley K, Stanton R, Maddalena R, Khosravi C, Teska P, Duggan K, Maillard JY. Impact of artificial accelerated ageing of PVC surfaces and surface degradation on disinfectant efficacy. J Hosp Infect 2024; 149:1-13. [PMID: 38734184 DOI: 10.1016/j.jhin.2023.12.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/06/2023] [Accepted: 12/17/2023] [Indexed: 05/13/2024]
Abstract
BACKGROUND Standardized efficacy surface tests for disinfectants are performed on pristine surfaces. There is a growing interest in understanding the impact of surface ageing on disinfectant activity, owing for example to the increased usage of ultraviolet (UV) radiation and oxidative chemistries for surface decontamination. This acknowledges that general surface 'wear and tear' following UV radiation and oxidative biocide exposure may impact biocidal product efficacy. METHODS PVC surfaces were aged through thermal and UV-A radiation (340 nm wavelength) following the use of standard ageing surface protocols to simulate natural surface degradation. Surface roughness, contact angle and scanning electron microscopy were performed to evaluate physical changes in PVC surfaces before and after artificial ageing. The efficacy of five pre-impregnated disinfectant wipes were evaluated using the ASTM E2967-15 on stainless-steel (control) and PVC surfaces (aged and non-aged). RESULTS The type of formulation and the organism tested remained the most significant factors impacting disinfectant efficacy, compared with surface type. Both thermal ageing and UV-A exposure of PVC surfaces clearly showed signs of surface degradation, notably an increase in surface roughness. Physical changes were observed in the roughness of PVC after artificial ageing. A difference in disinfectant efficacy dependent on aged PVC surfaces was observed for some, but not all formulations. CONCLUSION We showed that surface type and surface ageing can affect biocidal product efficacy, although in a non-predictable manner. More research is needed in this field to ascertain whether surface types and aged surfaces should be used in standardized efficacy testing.
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Affiliation(s)
- R Wesgate
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK
| | - K Bentley
- Infection & Immunity, School of Medicine, Cardiff University, Cardiff, UK
| | - R Stanton
- Infection & Immunity, School of Medicine, Cardiff University, Cardiff, UK
| | - R Maddalena
- School of Engineering, Cardiff University, Cardiff, UK
| | - C Khosravi
- School of Engineering, Cardiff University, Cardiff, UK
| | - P Teska
- Diversey, Fontenay-sous-Bois, France
| | - K Duggan
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK
| | - J-Y Maillard
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK.
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Belouadah Z, Nasri K, Toubal L. The Effects of Lignin on the Thermal and Morphological Properties and Damage Mechanisms after UV Irradiation of Polypropylene Biocomposites Reinforced with Flax and Pine Fibres: Acoustic Emission Analysis. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2474. [PMID: 38893738 PMCID: PMC11172832 DOI: 10.3390/ma17112474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 06/21/2024]
Abstract
This study investigates the impact of lignin on the durability and performance of polypropylene-based biocomposites (PP-flax and PP-pine) under environmental stresses such as UV radiation and moisture. The findings indicate that pine fibres, with their higher lignin content, are significantly more resistant to thermal degradation than flax fibres. Differential scanning calorimetry (DSC) showed that lignin influences crystallinity and melting temperatures across the composites, with variations corresponding to fibre type. Acoustic emissions analysis revealed that increasing the lignin content in pine fibres effectively reduces surface microcracks under UV exposure. Overall, these results underscore the importance of fibre composition in improving the performance and longevity of biocomposites, making them better suited for durable construction applications.
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Affiliation(s)
- Zouheyr Belouadah
- Laboratoire des Sciences et Techniques de l’Environnement, Ecole Nationale Polytechnique, 10 Avenue des Freres Oudek, BP 182, El-Harrach, Alger 16200, Algeria;
| | - Khaled Nasri
- Mechanical Engineering Department, Innovations Institute in Ecomaterials, Ecoproducts and Ecoenergy (I2E3), Université du Quebec à Trois-Rivières, 3351 Boul. des Forges, Trois Rivières, QC G9A 5H7, Canada;
| | - Lotfi Toubal
- Mechanical Engineering Department, Innovations Institute in Ecomaterials, Ecoproducts and Ecoenergy (I2E3), Université du Quebec à Trois-Rivières, 3351 Boul. des Forges, Trois Rivières, QC G9A 5H7, Canada;
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4
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Fan J, Zhang Q, Chen X, He Y. Interlaminar Shear Strength Change and Storage Life Prediction of Carbon Fiber/Epoxy Composites with Hygrothermal Accelerated Aging. Polymers (Basel) 2024; 16:1109. [PMID: 38675030 PMCID: PMC11053928 DOI: 10.3390/polym16081109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 04/04/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
In order to investigate the durability of fiber-reinforced polymer composites in hygrothermal environments, hygrothermal accelerate aging tests, for 360 days at 70 °C, RH70%; 70 °C, RH85%; 85 °C, RH70%; and 85 °C, RH85% and natural storage for 2 years in Guangzhou, China, were carried out for composite laminates. Then, the moisture absorption and interlaminar shear strength were measured. The hygrothermal damage mechanism of the composite was studied by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FSEM). A dual stress storage life prediction model and the equivalent relationship between natural storage and hygrothermal acceleration were established. The results show that the order of moisture absorption rates, moisture absorption contents, and the severity effect order on the interlaminar shear strength is RH85%; 85 °C > 70 °C; RH85% > 85 °C; RH70% > 70 °C; and RH70%. The time to achieve an effective moisture absorption balance is opposite to this. The moisture absorption rate meets Fick's law before the effective moisture absorption balance, and then shows a linear trend. The interlayer shear strength still decreases exponentially with aging, which is mainly caused by the resin plasticization and interface weakening. Hygrothermal accelerated aging for 13.4831 days at 85 °C; RH85% is equivalent to that for one-year actual storage in Guangzhou. According to the failure criterion of shear strength decreasing to 77%, the storage life of T700/epoxy in Guangzhou is 14.4661 years.
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Affiliation(s)
- Jinjuan Fan
- AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China
- Beijing Key Laboratory of Aeronautical Materials Testing and Evaluation, Beijing 100095, China
| | - Qin Zhang
- AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China
- Beijing Key Laboratory of Aeronautical Materials Testing and Evaluation, Beijing 100095, China
| | - Xinwen Chen
- AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China
- Beijing Key Laboratory of Aeronautical Materials Testing and Evaluation, Beijing 100095, China
| | - Yuhuai He
- AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China
- Beijing Key Laboratory of Aeronautical Materials Testing and Evaluation, Beijing 100095, China
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Plota-Pietrzak A, Czechowski L, Miszczak S, Masek A. Innovative Materials Based on Epoxy Resin for Use as Seat Elements in Bulk Transport. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1829. [PMID: 38673186 PMCID: PMC11051280 DOI: 10.3390/ma17081829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/10/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024]
Abstract
The subject of this research is the development of epoxy composites with a defined service life for the purpose of seat elements in rail vehicles, which will be more environmentally friendly. The produced materials based on epoxy resin filled with PLA or PLA and quercetin were subjected to solar aging tests for 800 h to investigate the impact of the additives used on the aging behavior of the epoxy matrix. Firstly, the TGA analysis showed that the use of the proposed additives allowed for the maintenance of the thermal stability of the epoxy resin. Moreover, based on an optical microscopy test, it was noticed that the introduction of PLA and PLA with quercetin did not contribute to an increase in matrix defects. The one-directional tensile tests carried out before and after solar aging showed that the presence of polylactide in epoxy composites causes a slight growth of the stiffness and strength. Based on contact angle and color change measurements, it was found that quercetin was oxidized, thus ensuring protection for the epoxy matrix. This phenomenon was confirmed by FTIR study, where the carbonyl index (CI) value for the R-PLA-Q composite was lower than for the reference sample. The obtained composite structures may be a good alternative to traditionally used systems as seat elements in rail vehicles, which are not only characterized by high aging resistance but are also more eco-friendly.
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Affiliation(s)
- Angelika Plota-Pietrzak
- Institute of Polymer and Dye Technology, Faculty of Chemistry, Lodz University of Technology, 90-537 Lodz, Poland;
| | - Leszek Czechowski
- Department of Strength of Materials, Lodz University of Technology, 90-537 Lodz, Poland;
| | - Sebastian Miszczak
- Institute of Materials Science and Engineering, Lodz University of Technology, 90-537 Lodz, Poland;
| | - Anna Masek
- Institute of Polymer and Dye Technology, Faculty of Chemistry, Lodz University of Technology, 90-537 Lodz, Poland;
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Maraveas C, Kyrtopoulos IV, Arvanitis KG, Bartzanas T. The Aging of Polymers under Electromagnetic Radiation. Polymers (Basel) 2024; 16:689. [PMID: 38475374 DOI: 10.3390/polym16050689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 02/27/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024] Open
Abstract
Polymeric materials degrade as they react with environmental conditions such as temperature, light, and humidity. Electromagnetic radiation from the Sun's ultraviolet rays weakens the mechanical properties of polymers, causing them to degrade. This study examined the phenomenon of polymer aging due to exposure to ultraviolet radiation. The study examined three specific objectives, including the key theories explaining ultraviolet (UV) radiation's impact on polymer decomposition, the underlying testing procedures for determining the aging properties of polymeric materials, and appraising the current technical methods for enhancing the UV resistance of polymers. The study utilized a literature review methodology to understand the aging effect of electromagnetic radiation on polymers. Thus, the study concluded that using additives and UV absorbers on polymers and polymer composites can elongate the lifespan of polymers by shielding them from the aging effects of UV radiation. The findings from the study suggest that thermal conditions contribute to polymer degradation by breaking down their physical and chemical bonds. Thermal oxidative environments accelerate aging due to the presence of UV radiation and temperatures that foster a quicker degradation of plastics.
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Affiliation(s)
- Chrysanthos Maraveas
- Department of Natural Resources Development and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens, Greece
| | - Ioannis Vasileios Kyrtopoulos
- Department of Natural Resources Development and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens, Greece
| | - Konstantinos G Arvanitis
- Department of Natural Resources Development and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens, Greece
| | - Thomas Bartzanas
- Department of Natural Resources Development and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens, Greece
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Wang XJ, Travis C, Sorna MT, Arola D. Durability of Ultem 9085 in Marine Environments: A Consideration in Fused Filament Fabrication of Structural Components. Polymers (Basel) 2024; 16:350. [PMID: 38337238 DOI: 10.3390/polym16030350] [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: 12/05/2023] [Revised: 01/21/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
The long-term durability of polymer components produced by additive manufacturing (AM) in marine conditions is poorly understood. Here, fused filament fabrication (FFF) of Ultem 9085 was conducted and accelerated aging was performed. Two printing orientations (-45/45° and 0/90°) and two sample types (ASTM D638 Type 1 and Type 4) were produced and subjected to accelerated aging in either seawater or air. Results from tensile tests showed that the elastic modulus, yield strength and ultimate tensile strength increased after seawater aging, whereas the elongation to failure decreased. Results of thermogravimetric analysis (TGA) and derivative-TGA curves indicated that hydrolysis occurred after seawater exposure to the polycarbonate (PC) component and changes in structure or hydrogen bonds formed in the polyetherimide (PEI) component. Differential scanning calorimetry showed that physical aging occurred after short exposure periods and low temperature. Longer exposures and higher temperatures resulted in increasing plasticization by water and scission of the PC molecules. Results from Raman suggest that hydrolysis of the PC occurred, with a reduction in free volume produced by physical aging or hydrogen bonding with water molecules. These results highlight that Ultem 9085 is susceptible to degradation in marine environments, and there are two primary mechanisms, including physical and chemical aging. Their specific contribution is highly sensitive to the aging temperature and require careful selection in accelerated aging evaluations.
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Affiliation(s)
- Xiong Julia Wang
- Department of Materials Science and Engineering, University of Washington, Box 352120, Seattle, WA 98195-2120, USA
| | - Carly Travis
- Department of Materials Science and Engineering, University of Washington, Box 352120, Seattle, WA 98195-2120, USA
| | - Mark T Sorna
- Naval Undersea Warfare Center, Keyport, WA 98345-7610, USA
| | - Dwayne Arola
- Department of Materials Science and Engineering, University of Washington, Box 352120, Seattle, WA 98195-2120, USA
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195-2120, USA
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Zhang T, Zhang J, Zhao Y, Ai H. Study on the Performance and Mechanism of Glass Fiber-Reinforced MgO-SiO 2-H 2O Cement. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6668. [PMID: 37895650 PMCID: PMC10608568 DOI: 10.3390/ma16206668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/09/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023]
Abstract
The magnesium silicate hydrate system (MgO-SiO2-H2O) possesses issues such as susceptibility to cracking, brittleness, and poor volumetric stability, which hinder its development and practical use in engineering applications. This study aimed to enhance the properties of the MgO-SiO2-H2O system by incorporating glass fiber as a reinforcing material. The mechanical properties, shrinkage properties, and properties during accelerated aging were tested at different content levels of glass fiber. Additionally, the reaction mechanism and microscopic morphology were characterized using microscopic testing methods. The results revealed that the addition of glass fiber improved the mechanical properties of the MgO-SiO2-H2O system; meanwhile, with an increase in fiber content, the mechanical properties showed an initial increase followed by a decreasing trend. With a glass fiber content of 0.6%, the system exhibited a flexural strength of 7.9 MPa at 28 d, a compressive strength of 42.5 MPa at 28 d, and a 27.2% increase in splitting tensile strength compared to the control group. At a fiber content of 0.9%, the flexural toughness steadily increased, reaching a maximum value of 2.238 N·m, which is 5.41 times greater than that of the control group. Moreover, the incorporation of glass fiber effectively inhibited the shrinkage of the MgO-SiO2-H2O system. Accelerated aging experiments confirmed that the glass fiber in the MgO-SiO2-H2O system did not undergo significant deterioration or corrosion, thereby maintaining long-term stability. These findings have important theoretical and practical significance for the application and development of the MgO-SiO2-H2O system.
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Affiliation(s)
| | | | | | - Hongmei Ai
- Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian 116024, China; (T.Z.); (J.Z.); (Y.Z.)
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Kalyoncuoğlu ÜT, Yilmaz B, Sipahi C. Determination of the degree of conversion, the diffuse reflectance, and the color stability after different aging processes of gingiva-colored composite resins. J Prosthodont 2023; 32:743-751. [PMID: 37291715 DOI: 10.1111/jopr.13721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 05/29/2023] [Accepted: 05/31/2023] [Indexed: 06/10/2023] Open
Abstract
PURPOSE To determine the degree of conversion (DC) and spectral diffuse reflectance of four different gingiva-colored composites and to evaluate their color stability after various aging processes. MATERIALS AND METHODS The gingiva-colored composites were assigned to four experimental groups (Anaxgum (AG), Crea.lign paste Gum (CB), Gradia Gum (GR), SR Nexco Gum (NC)). A total of 120 disc-shaped specimens (10 × 2 mm) (n = 30/group) were polymerized in a Teflon mold. The nature of chemical bonding was studied by Fourier transform infrared spectroscopy (FTIR). Diffuse reflection spectra of the polymerized specimens were gathered using an ultraviolet-visible-near infrared (UV-Vis-NIR) spectrophotometer. Specimens subjected to aging methods were divided into three subgroups (n = 10): ultraviolet aging, hydrothermal aging, and autoclave aging. Color differences (ΔE*ab and ΔE00 ) were determined by colorimetry before and after aging. The statistical analysis was done using a two-way ANOVA along with paired sample t-test and Bonferroni's post hoc test. RESULTS Conversion degrees varied between 26.9% and 59.7% and all groups showed 3 or 4 maxima at different positions in the visible region of the spectrum. Both ΔE*ab and ΔE00 values were significantly different from the groups of different brands for all types of aging processes. Similarly, there were significantly different ΔE*ab and ΔE00 values according to the aging procedure for all groups of particular brands, except for ΔE00 of SR Nexco Gum (NC). CONCLUSIONS The aging procedures resulted in significant color differences between similar shades of four commercial gingiva-colored composites. The composite resins showed different degrees of conversion and diffuse reflectance spectra. The aging conditions tested affected the color stability. Patients with gingiva-colored indirect restorations should be informed about time-dependent discoloration.
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Affiliation(s)
- Ülkü Tuğba Kalyoncuoğlu
- Department of Prosthodontics, Faculty of Gülhane Dentistry, University of Health Sciences Turkey, Ankara, Turkey
| | - Bengi Yilmaz
- Department of Biomaterials, University of Health Sciences Turkey, Istanbul, Turkey
- Experimental Medicine Research and Application Center, University of Health Sciences Turkey, Istanbul, Turkey
| | - Cumhur Sipahi
- Department of Prosthodontics, University of Health Sciences Turkey, Faculty of Gülhane Dentistry, Ankara, Turkey
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Plota A, Masek A. Analysis of the aging and stabilization processes in cyclic polyolefins containing various natural or synthetic stabilizers. POLYMER 2023. [DOI: 10.1016/j.polymer.2023.125879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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11
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On the evaluation of viscoelastic response of aged PLA/bagasse bio-composites. Polym Bull (Berl) 2022. [DOI: 10.1007/s00289-022-04622-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Evaluation of plastic packaging waste degradation in seawater and simulated solar radiation by spectroscopic techniques. Polym Degrad Stab 2022. [DOI: 10.1016/j.polymdegradstab.2022.110215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Lewandowska H, Sadło J. Radical Composition and Radical Reaction Kinetics in the Probe-Irradiated XLPE Samples as a Potential Source of Information on Their Aging Degree. MATERIALS (BASEL, SWITZERLAND) 2022; 15:5723. [PMID: 36013865 PMCID: PMC9414847 DOI: 10.3390/ma15165723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
Polyethylene is a model polyolefin, and a widely used material for the manufacture of many products, including cable sheaths. Understanding degradation mechanisms at the atomic scale leading to oxidation during aging is crucial for many long-term applications. The concentrations of radicals derived from oxidation and chain scission during radio-oxidation, as well as their ratio, are important parameters controlling the predominance of chain scission or crosslinking of the polymer. In this work, we propose a cryogenic EPR technique for measuring oxidation- and fragmentation-derived radicals as a less-destructive method for the evaluation of cable insulation aging and performance capability. We investigate the effect of the low-dose and high-dose radiation aging on the formation of free radicals in the polymer matrix that are both unprotected and protected by antioxidants. The stability of radicals after aging is a determinant of macroscopic processes and structural changes during aging. Under the conditions of the higher dose rate, the peroxy radical buildup is lower per dose. Peroxy radical buildup is followed by decay during aging, in accordance with POOH content. Our results allow the prediction of the capability of the antioxidant to protect the XLPE material in the function of dose and time.
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14
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Frigione M. Assessment of the Ageing and Durability of Polymers. Polymers (Basel) 2022; 14:polym14101934. [PMID: 35631816 PMCID: PMC9146485 DOI: 10.3390/polym14101934] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 05/07/2022] [Indexed: 12/04/2022] Open
Affiliation(s)
- Mariaenrica Frigione
- Innovation Engineering Department, University of Salento, Prov. le Lecce-Monteroni, 73100 Lecce, Italy
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15
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Abstract
Electrical insulation is an integral part of power components. The aging of electrical insulation is an undeniable fact that limits the operational lifetime of power components. Apart from regular aging, abnormal stresses and the development of defects are real threats because of their contribution in accelerating the aging rate and thereby leading to a premature failure of the power components. Over the decades, various studies have been carried out to understand the aging behavior of electrical insulation mainly considering electrical and thermal stresses. Similarly, a number of mathematical (aging) models have been developed based on the theoretical and experimental investigations and evidences. However, a dependable formulation of the models that can provide more practical estimation of the insulation degradation profile has not been achieved yet. This paper presents a comprehensive review of the aging models considering single and multistress conditions. Further, the paper discusses possible challenges and barricades averting the conventional models to achieve a suitable accuracy. Finally, suggestions are provided that can be considered to improve the modeling approaches and their performance.
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Starkova O, Gagani AI, Karl CW, Rocha IBCM, Burlakovs J, Krauklis AE. Modelling of Environmental Ageing of Polymers and Polymer Composites—Durability Prediction Methods. Polymers (Basel) 2022; 14:polym14050907. [PMID: 35267730 PMCID: PMC8912441 DOI: 10.3390/polym14050907] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/15/2022] [Accepted: 02/21/2022] [Indexed: 02/07/2023] Open
Abstract
Polymers and polymer composites are negatively impacted by environmental ageing, reducing their service lifetimes. The uncertainty of the material interaction with the environment compromises their superior strength and stiffness. Validation of new composite materials and structures often involves lengthy and expensive testing programs. Therefore, modelling is an affordable alternative that can partly replace extensive testing and thus reduce validation costs. Durability prediction models are often subject to conflicting requirements of versatility and minimum experimental efforts required for their validation. Based on physical observations of composite macroproperties, engineering and phenomenological models provide manageable representations of complex mechanistic models. This review offers a systematised overview of the state-of-the-art models and accelerated testing methodologies for predicting the long-term mechanical performance of polymers and polymer composites. Accelerated testing methods for predicting static, creep, and fatig ue lifetime of various polymers and polymer composites under environmental factors’ single or coupled influence are overviewed. Service lifetimes are predicted by means of degradation rate models, superposition principles, and parametrisation techniques. This review is a continuation of the authors’ work on modelling environmental ageing of polymer composites: the first part of the review covered multiscale and modular modelling methods of environmental degradation. The present work is focused on modelling engineering mechanical properties.
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Affiliation(s)
- Olesja Starkova
- Institute for Mechanics of Materials, University of Latvia, Jelgavas 3, LV-1004 Riga, Latvia;
- Correspondence:
| | - Abedin I. Gagani
- Siemens Digital Industries Software, Via Werner von Siemens 1, 20128 Milan, Italy;
| | | | - Iuri B. C. M. Rocha
- Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, The Netherlands;
| | - Juris Burlakovs
- Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, 5 Kreutzwaldi St., 51014 Tartu, Estonia;
| | - Andrey E. Krauklis
- Institute for Mechanics of Materials, University of Latvia, Jelgavas 3, LV-1004 Riga, Latvia;
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An Accelerated Aging Test to Compare the Thermal Stability over Time between the Mint Lift® and the MEDI ROPE. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12052311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
It is allegedly known that the thermal stability of the Mint Lift® (the Mint Lift® 17 and the Mint Lift® Fine; HansBiomed Co., Ltd., Seoul, Korea) over time might be lower as compared with thread-lifts processed through ultrasonic molding technology, such as the MEDI ROPE (WSM 19-03; CNG Co., Ltd., Gyeonggi, Korea), because the Mint Lift® undergoes a thermal treatment during the manufacturing process. We conducted this accelerated aging test to compare the thermal stability over time between the Mint Lift® and the MEDI ROPE. Thus, we measured the degrees of strength of the MEDI ROPE, the Mint Lift® 17, and the Mint Lift® Fine at 0, 2, 3, 4, 5, 7, 8, 9, 10, 11, 14, and 17 weeks. Between 0 and 14 weeks, the Mint Lift® 17 and the Mint Lift® Fine had significantly higher degrees of strength as compared with the MEDI ROPE (p < 0.05). At 0, 5, and 10 weeks, the Mint Lift® 17 and the Mint Lift® Fine showed no notable differences in microscopic findings as compared with the MEDI ROPE. At 20 weeks, however, the integrities of the Mint Lift® 17 and the Mint Lift® Fine were better preserved as compared with the MEDI ROPE. In conclusion, our results indicate that the Mint Lift® 17 and the Mint Lift® Fine might be less vulnerable to degradation over time as compared with the MEDI ROPE under thermal conditions.
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Kim S, Lee Y, Kim C, Choi S. Analysis of Mechanical Property Degradation of Outdoor Weather-Exposed Polymers. Polymers (Basel) 2022; 14:357. [PMID: 35054761 PMCID: PMC8782030 DOI: 10.3390/polym14020357] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 01/10/2022] [Accepted: 01/13/2022] [Indexed: 11/17/2022] Open
Abstract
It is well known that many polymers are prone to outdoor weathering degradation. Therefore, to ensure the safety and integrity of the structural parts and components made from polymers for outdoor use, their weather-affected mechanical behavior needs to be better understood. In this study, the critical mechanical property for degradation was identified and modeled into a usable format for use in the virtual analysis. To achieve this, an extensive 4-year outdoor weathering test was carried out on polycarbonate (PC), polypropylene (PP), polybutylene terephthalate (PBT), and high-density polyethylene (HDPE) polymers up to a total UV irradiation of 1020 MJ/m2 at a 315~400 nm wavelength. In addition, tensile tests were performed by collecting five specimens for each material at every 60 MJ/m2 interval. With the identification of fracture strain retention as the key performance index for mechanical property degradation, a fracture strain retention function was developed using logistic regression analysis for each polymer. In addition, a method for using fracture strain retention function to establish a mechanical property degradation dataset was proposed and successfully tested by performing weathering FE analysis on the virtual automotive collision behavior of a PC part under intermittent UV irradiation doses. This work showed the potential of using fracture strain retention function to predict the performance of polymeric components undergoing mechanical property degradation upon outdoor weathering.
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Affiliation(s)
- Sunwoo Kim
- Department of Polymer Science and Engineering, Hannam University, Daejeon 34054, Korea;
- Chemical Materials Solutions Center, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea
| | - Youngmin Lee
- Advanced Materials R&D, LG Chem Ltd., Daejeon 34122, Korea;
| | - Changhwan Kim
- Climate & Environmental Real-Scale Testing Center, Korea Conformity Laboratories, Jincheon-gun 27872, Korea;
| | - Sunwoong Choi
- Department of Polymer Science and Engineering, Hannam University, Daejeon 34054, Korea;
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