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Potolinca VO, Oprea S. New polyurethanes containing cycloaliphatic units in the hard segments. The influence of the microstructure on the thermo‐mechanical and surface properties. POLYM ADVAN TECHNOL 2022. [DOI: 10.1002/pat.5962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
| | - Stefan Oprea
- “Petru Poni” Institute of Macromolecular Chemistry Iasi Romania
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Kuo L, Luijten BJ, Li S, de Moraes ACM, Silvaroli AJ, Wallace SG, Hui J, Downing JR, Shull KR, Hersam MC. Sterilizable and Reusable UV-Resistant Graphene-Polyurethane Elastomer Composites. ACS APPLIED MATERIALS & INTERFACES 2022; 14:53241-53249. [PMID: 36394995 DOI: 10.1021/acsami.2c17791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Shortages of personal protective equipment (PPE) at the start of the COVID-19 pandemic caused medical workers to reuse medical supplies such as N95 masks. While ultraviolet germicidal irradiation (UVGI) is commonly used for sterilization, UVGI can also damage the elastomeric components of N95 masks, preventing effective fit and thus weakening filtration efficacy. Although PPE shortage is no longer an acute issue, the development of sterilizable and reusable UV-resistant elastomers remains of high interest from a long-term sustainability and health perspective. Here, graphene nanosheets, produced by scalable and sustainable exfoliation of graphite in ethanol using the polymer ethyl cellulose (EC), are utilized as UV-resistant additives in polyurethane (PU) elastomer composites. By increasing the graphene/EC loading up to 1 wt %, substantial UV protection is imparted by the graphene nanosheets, which strongly absorb UV light and hence suppress photoinduced degradation of the PU matrix. Additionally, graphene/EC provides mechanical reinforcement, such as increasing Young's modulus, elongation at break, and toughness, with negligible changes following UV exposure. These graphene/EC-PU composites remain mechanically robust over at least 150 sterilization cycles, enabling safe reuse following UVGI. Beyond N95 masks, these UVGI-compatible graphene/EC-PU composites have potential utility in other PPE applications to address the broader issue of single-use waste.
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Affiliation(s)
- Lidia Kuo
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Benjamin J Luijten
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Siyang Li
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Ana C M de Moraes
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Anthony J Silvaroli
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Shay G Wallace
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Janan Hui
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Julia R Downing
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Kenneth R Shull
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, United States
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3
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Ali B, Irshad A, Atif M. Bio‐based photo‐curable polyurethane composites. POLYM ADVAN TECHNOL 2022. [DOI: 10.1002/pat.5909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Basharat Ali
- Chemistry Department University of Education Lahore (Vehari Campus) Vehari Pakistan
| | - Adnan Irshad
- Chemistry Department University of Education Lahore (Vehari Campus) Vehari Pakistan
| | - Muhammad Atif
- Chemistry Department University of Education Lahore (Vehari Campus) Vehari Pakistan
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Henke M, Lis B, Krystofiak T. Evaluation of Surface Roughness Parameters of HDF for Finishing under Industrial Conditions. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6359. [PMID: 36143669 PMCID: PMC9506473 DOI: 10.3390/ma15186359] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 09/04/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
One of the most important properties of the surface of wood-based panels is their roughness. This property determines the way of working with the material in the processes of gluing and surface varnishing. The aim of this study was to determine the effect of various sanding belt configurations and the feeding speed of the conveyor belt during grinding on the surface roughness of high-density fiberboards (HDF). The research material was prepared under industrial conditions. Three types of boards were selected for the tests. After grinding, the roughness parameters were measured both transversely and longitudinally relative to the grinding direction, using a Mitutoyo SJ-210 profilometer and the optical method. Based on ANOVA analysis of the data, it was found that the type of HDF boards used and the configuration of the abrasive belts had a statistically significant impact on the roughness. The samples for which the grinding process was performed with sanding belts of the highest grain size had the lowest roughness. For the amplitude roughness parameters, the direction of roughness measurement had a significant influence. These results may provide valuable guidance for the furniture industry in the preparation of HDF for furniture production.
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A Novel Approach for Wind Turbine Blade Erosion Characterization: An Investigation Using Surface Gloss Measurement. COATINGS 2022. [DOI: 10.3390/coatings12070928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Wind turbine blade erosion is typically assessed in situ using visual inspection, which is a rudimentary qualitative assessment of the condition of the blade coating system. On coated test specimens in laboratory test conditions, mass loss can provide a better understanding of the stage of erosion, but cannot be extended to real world applications. In this work, by using analysis of photographs, microscopy images, mass data, and gloss data together, it was found that gloss measurements can effectively quantify changes in coating microstructure as a result of rain erosion. This was achieved by correlating and comparing mass loss measurements over time with surface gloss and verifying the erosion stages with photographs and microscopy images. As such, gloss was shown to represent the erosion stages with greater accuracy than the current industry methods. This novel technique has been shown to identify the incubation period, that is the onset of erosion damage, by detecting microstructure changes which are not visible to the naked eye, nor is determinable by mass loss. The quantitative output from the gloss methodology thus allows wind turbine owners and operators to assess, manage, and plan more efficiently for costly erosion repairs and future inspections. The system is presently being used in a laboratory setting, though it has the potential to be combined with drones or climber robots to be remotely used within the wind farm.
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de Melo TP, Delgado A, Martins R, Lassila L, Garoushi S, Caldeira J, Azul AM, Vallittu P. Can Specular Gloss Measurements Predict the Effectiveness of Finishing/Polishing Protocols in Dental Polymers? A Systematic Review and Linear Mixed-effects Prediction Model. Oper Dent 2022; 47:E131-E151. [PMID: 35776960 DOI: 10.2341/21-027-lit] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2021] [Indexed: 11/23/2022]
Abstract
PURPOSE The current gold standard measure to assess polishing efficacy is surface roughness (SR) assessed in laboratory research. Specular gloss (SG) has been negatively correlated to SR, which raises the following question: Can SG be used to accurately determine the effectiveness of a finishing/polishing procedure in direct resin composites? METHODS A systematic approach and search strategy, following Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, was developed and conducted in five electronic databases: PubMed/Medline, Scopus, Web of Science, EMBASE (Ovid), and SciELO/LILACS to identify laboratory studies that assessed SR and SG, simultaneously, of resin composites, without date or language restriction. Risk of bias assessment was carried out by two reviewers, independently. From the extracted quantitative data of SG/SR, regression analyses were performed, and a linear mixed-effects prediction model was derived using the nimble package in R (v4.0.3). RESULTS A total of 928 potential studies were found, out of which, 13 were eligible after criterion screening. Experimental groups featured 31 resin composites of six different filler types, with the most common being microhybrids followed by nanohybrids. More than half of the studies initially reported a linear correlation between SR and SG, which ranged from r2 = 0.34-0.96. Taking into account the regression analysis and prediction model posteriorly performed, the corresponding SG threshold for 0.2 μm is estimated to be >55 GU. Most of the evidence was classified as moderate or high risk of bias. CONCLUSION SG is universally correlated to SR in polymers, and a reference value of >55 GU is proposed, above which samples are considered well polished.
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Affiliation(s)
- T P de Melo
- *Teresa Pinheiro de Melo, DDS, Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Monte de Caparica, Portugal
| | - Ahs Delgado
- António HS Delgado, DDS, Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Monte de Caparica, Portugal; 2 Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, UK
| | - R Martins
- Rui Martins, Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Monte de Caparica, Portugal
| | - L Lassila
- Lippo Lassila, Department of Biomaterials Science and TCBC, Institute of Dentistry, University of Turku, Turku, Finland
| | - S Garoushi
- Sufyan Garoushi, Department of Biomaterials Science and TCBC, Institute of Dentistry, University of Turku, Turku, Finland
| | - J Caldeira
- Jorge Caldeira, Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Monte de Caparica, Portugal; UCIBIO and LAQV Requimte Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - A M Azul
- Ana Mano Azul, Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Monte de Caparica, Portugal
| | - P Vallittu
- Pekka Vallittu, Department of Biomaterials Science and TCBC, Institute of Dentistry, University of Turku, Turku, Finland; Division of Welfare, City of Turku, Turku, Finland
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Potolinca VO, Oprea S. An insight on the effect of the hard segment domain on the thermo‐mechanical and surface properties of new piperazine‐based polyurethanes. J Appl Polym Sci 2022. [DOI: 10.1002/app.52467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Violeta Otilia Potolinca
- Department of Polyaddition and Photochemistry “Petru Poni” Institute of Macromolecular Chemistry Iasi Romania
| | - Stefan Oprea
- Department of Polyaddition and Photochemistry “Petru Poni” Institute of Macromolecular Chemistry Iasi Romania
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Yong Q, Xu D, Liu Q, Xiao Y, Wei D. Advances in polymer‐based matte coatings: A review. POLYM ADVAN TECHNOL 2022. [DOI: 10.1002/pat.5508] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Qiwen Yong
- Institute of Applied Chemistry Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University Nanchong China
- College of Chemistry and Chemical Engineering China West Normal University Nanchong China
| | - Dan Xu
- College of Chemistry and Chemical Engineering China West Normal University Nanchong China
| | - Qi Liu
- Institute of Applied Chemistry Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University Nanchong China
- College of Chemistry and Chemical Engineering China West Normal University Nanchong China
| | - Yao Xiao
- College of Chemistry and Chemical Engineering China West Normal University Nanchong China
| | - Daidong Wei
- Chinese Academy of Sciences Guangzhou Chemical Grouting Co., Ltd. Guangzhou China
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Abstract
3D surface roughness measurement is still a less mature procedure than its 2D version. The size of the evaluation area is not as standardized as the measurement length in the 2D version. The purpose of this study is to introduce a method for minimizing the evaluated surface area. This could help industrial applications in minimizing the time and cost of measurements. Machining experiments (hard turning and infeed grinding) and surface roughness measurements were carried out for automotive industrial parts to demonstrate the introduced method. Some frequently used roughness parameters were analyzed. Basic statistical calculations were applied to analyze the relationship between the surface area and the roughness parameter values and regression analyses were applied to validate the results in case of the applied technological data. The main finding of the study is that minimum evaluation areas can be clearly designated and, depending on the different roughness parameter–procedure version, different evaluation sizes (Sa: 1.3 × 1.3 mm; Sq: 1.4 × 1.4 mm; Ssk and Sku: 2 × 2 m; Sp and Sv: 1.7 × 1.7 mm) are recommended.
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Cheumani Yona AM, Žigon J, Ngueteu Kamlo A, Pavlič M, Dahle S, Petrič M. Preparation, Surface Characterization, and Water Resistance of Silicate and Sol-Silicate Inorganic-Organic Hybrid Dispersion Coatings for Wood. MATERIALS (BASEL, SWITZERLAND) 2021; 14:3559. [PMID: 34202131 PMCID: PMC8269507 DOI: 10.3390/ma14133559] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/13/2021] [Accepted: 06/17/2021] [Indexed: 11/17/2022]
Abstract
The purpose of this study was to comparatively investigate the behavior of silicate and sol-silicate coatings non-modified or modified with an organosilane on wood and on wood pre-coated with silica-mineralized primers. Adhesion strength, morphology, and water permeability and related damages were studied to evaluate the possibility of utilizing such inorganic-based coating systems for durable protection of wood without or with relatively cheap and water-borne primers. Potassium silicate and potassium methylsiliconate aqueous solutions and a colloidal silica were used for the preparation of the coatings. The white coating paints were brushed on beech wood substrates at a rate of 220 g·m-2. The coatings exhibited good coverage ability. The pull-off adhesion strength values appeared to be related to pH following a polynomial law. The adhesion strength for the silicate coatings were adequate (above 3 MPa and up to 5 MPa) for wood, whereas the values for the sol-silicates were too low for practical applications. The adhesion values were in general higher for the samples cured in a climate room (23 ± 3 °C and 75 ± 2% relative humidity) than the samples cured in the ambient atmosphere of the laboratory (23 ± 3 °C and 25 ± 5% relative humidity). The presence of microdefects (cracks, holes) was revealed in the coating layers by optical and scanning electron microscopy. The surface roughness parameters assessed by confocal scanning laser microscopy were dependent on the magnification applied for their measurement. The arithmetic average roughness Sa was between 5 µm and 10 µm at magnification 5× and between 2.5 μm and 10 µm at magnification 20×. The maximum peak-to-valley height Sz confirmed the presence of open pores emerging through the coatings. The open pores constitute free pathways for water ingress through the coatings, and could explain the high water absorption of the coatings including the methysiliconate-containing silicate coating and despite the relatively high water contact angle and low wettability exhibited by this sample. The post-application of a hydrophobizing solution containing hexadecyltrimethoxysilane and dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride considerably reduced the water permeability, while application of nanosilica-containing organic primers increased the adhesion for the coatings. Silicate coatings with adhesion great enough and resistance against water damages can be generated on wood even without a primer using low silica-to-alkali ratio binders and an organosilane additive. The sol-silicate coatings appear to be applicable only with a primer. The improvement of the paint formulations to control the formation of microcracks and open pores could be useful to reduce the liquid water permeability and increase durability. Otherwise, the application of a hydrophobizing treatment can be used for this purpose.
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Affiliation(s)
- Arnaud Maxime Cheumani Yona
- Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva ulica 101, SI-1000 Ljubljana, Slovenia; (J.Ž.); (M.P.); (S.D.); (M.P.)
- Macromolecular Research Team, Faculty of Science, University of Yaoundé 1, Yaoundé P.O. Box 812, Cameroon;
| | - Jure Žigon
- Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva ulica 101, SI-1000 Ljubljana, Slovenia; (J.Ž.); (M.P.); (S.D.); (M.P.)
| | - Alexis Ngueteu Kamlo
- Macromolecular Research Team, Faculty of Science, University of Yaoundé 1, Yaoundé P.O. Box 812, Cameroon;
| | - Matjaž Pavlič
- Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva ulica 101, SI-1000 Ljubljana, Slovenia; (J.Ž.); (M.P.); (S.D.); (M.P.)
| | - Sebastian Dahle
- Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva ulica 101, SI-1000 Ljubljana, Slovenia; (J.Ž.); (M.P.); (S.D.); (M.P.)
| | - Marko Petrič
- Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva ulica 101, SI-1000 Ljubljana, Slovenia; (J.Ž.); (M.P.); (S.D.); (M.P.)
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