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Wang X, Gao K, Caldona EB, Ali MRR, Zhang X, Zhang Z. Cellulose nanocrystals-reinforced waterborne epoxy coatings with enhanced corrosion resistance for steel. Int J Biol Macromol 2024; 257:128755. [PMID: 38092115 DOI: 10.1016/j.ijbiomac.2023.128755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 12/06/2023] [Accepted: 12/09/2023] [Indexed: 12/18/2023]
Abstract
The practical applications of waterborne epoxy coatings are limited due to their poor barrier properties caused by the formation of numerous micropores and defects during the curing process. Herein, cellulose nanocrystals (CNCs)-reinforced waterborne epoxy coatings were fabricated by the direct addition of 0.2-1.0 wt% CNCs to waterborne epoxy emulsion followed by amine curing agent addition and spray coating. The incorporation of 0.2-0.5 wt% CNCs had no discernible impact on the stability of the waterborne epoxy emulsion. This led to the uniform dispersion of CNCs in the cured coating matrix, as evidenced by differential scanning calorimetry analysis. Because of the good compatibility, 0.2-0.5 wt% CNCs-reinforced epoxy coatings exhibited superior corrosion protection performance for steels. The impedance modulus of these coatings remained at 108 Ω cm2 after being immersed in a 3.5 wt% NaCl solution for 21 d. The hydroxyl groups present on the CNC surface undergo a reaction with the epoxy group, enhancing intermolecular interaction and leading to the formation of a defect-free dense structure that improves coating barrier properties. However, the incorporation of an excessive amount of CNCs (i.e., 0.8 and 1.0 wt%) significantly compromised the corrosion resistance of epoxy coatings due to aggregation-induced coating defects. Overall, this study provides a facile and green strategy for corrosion resistance improvement of waterborne epoxy coatings.
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Affiliation(s)
- Xiang Wang
- College of Civil and Transportation Engineering, Guangdong Province Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, China; Center of Chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Kun Gao
- Center of Chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Eugene B Caldona
- Department of Coatings and Polymeric Materials, North Dakota State University, Fargo, ND 58102, United States
| | - Mark Rigel R Ali
- Department of Coatings and Polymeric Materials, North Dakota State University, Fargo, ND 58102, United States
| | | | - Zhao Zhang
- Department of Coatings and Polymeric Materials, North Dakota State University, Fargo, ND 58102, United States.
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Huo M, Chen J, Jin C, Huo S, Liu G, Kong Z. Preparation, characterization, and application of waterborne lignin-based epoxy resin as eco-friendly wood adhesive. Int J Biol Macromol 2024; 259:129327. [PMID: 38219939 DOI: 10.1016/j.ijbiomac.2024.129327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/17/2023] [Accepted: 01/06/2024] [Indexed: 01/16/2024]
Abstract
A series of novel waterborne lignin-based epoxy resin emulsions (WLEPs) were successfully synthesized, and then the WLEPs were cured with polyamide (PA) to give formaldehyde-free wood adhesives with high-performance. The chemical structures and properties of WLEP emulsions were determined. The effects of the emulsifiers on thermal and mechanical properties of the adhesives were investigated, and the potential application of WLEPs in the formulation of plywood were also evaluated. The results demonstrated that the WLEP dispersions presented excellent storage stability (>180 days) with their viscosities range from 110 mPa·s to 470 mPa·s and particle sizes in the range of 321-696 nm, which were beneficial for the fluidity and permeability of the wood adhesives. Furthermore, the thermal and mechanical properties of adhesives could be tuned effectively by controlling the length of PEG chains. The adhesive bearing PEG 6000 exhibited the highest tensile strength of 24.0 MPa and Young's modulus of 1439 MPa. Notably, the plywood prepared with the resulting adhesives displayed good bonding performance, especially water resistance, which were much higher than the national standard requirement for exterior-grade plywood type I. These results indicated that the WLEPs could be used as sustainable alternatives for traditional formaldehyde-based wood adhesives in practical applications.
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Affiliation(s)
- Meiyu Huo
- Institute of Chemical Industry of Forest Products, CAF, Key Lab. of Biomass Energy and Material, Jiangsu Province, Key Lab. of Chemical Engineering of Forest Products, National Forestry and Grassland Administration; National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass, Nanjing 210042, China; Co-Innovation Center of Efficient Processing and Utilization of Forest Resources of Jiangsu Province, Nanjing 210037, China
| | - Jian Chen
- Institute of Chemical Industry of Forest Products, CAF, Key Lab. of Biomass Energy and Material, Jiangsu Province, Key Lab. of Chemical Engineering of Forest Products, National Forestry and Grassland Administration; National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass, Nanjing 210042, China; Co-Innovation Center of Efficient Processing and Utilization of Forest Resources of Jiangsu Province, Nanjing 210037, China
| | - Can Jin
- Institute of Chemical Industry of Forest Products, CAF, Key Lab. of Biomass Energy and Material, Jiangsu Province, Key Lab. of Chemical Engineering of Forest Products, National Forestry and Grassland Administration; National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass, Nanjing 210042, China; Co-Innovation Center of Efficient Processing and Utilization of Forest Resources of Jiangsu Province, Nanjing 210037, China
| | - Shuping Huo
- Institute of Chemical Industry of Forest Products, CAF, Key Lab. of Biomass Energy and Material, Jiangsu Province, Key Lab. of Chemical Engineering of Forest Products, National Forestry and Grassland Administration; National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass, Nanjing 210042, China; Co-Innovation Center of Efficient Processing and Utilization of Forest Resources of Jiangsu Province, Nanjing 210037, China
| | - Guifeng Liu
- Institute of Chemical Industry of Forest Products, CAF, Key Lab. of Biomass Energy and Material, Jiangsu Province, Key Lab. of Chemical Engineering of Forest Products, National Forestry and Grassland Administration; National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass, Nanjing 210042, China; Co-Innovation Center of Efficient Processing and Utilization of Forest Resources of Jiangsu Province, Nanjing 210037, China.
| | - Zhenwu Kong
- Institute of Chemical Industry of Forest Products, CAF, Key Lab. of Biomass Energy and Material, Jiangsu Province, Key Lab. of Chemical Engineering of Forest Products, National Forestry and Grassland Administration; National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass, Nanjing 210042, China; Co-Innovation Center of Efficient Processing and Utilization of Forest Resources of Jiangsu Province, Nanjing 210037, China
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