Functional hydrophobic coating for phosphogypsum via stoichiometric silanization, hydrophobic characterization, microstructure analysis, and durability evaluation. (12th September 2022)

• Record Type: Journal Article
• Authors: Chen, Jiajun; Wei, Chao; Ran, Jingyu; Su, Xiangdong; Wang, Wei; Zhang, Jie
• Is Part Of: Construction & building materials. Volume 347(2022)
• Publication Date: 2022-09-12
• Subjects: Octadecyltrichlorosilane (OTS) -- β-hemihydrate phosphogypsum (β-HPG) -- Hydrophobic agent -- Stoichiometric silanization -- Durability; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2022.128560
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: The micro/nano-layered siloxane aggregates are generated in a low-cost solvent. The stoichiometric reaction between OTS and industrial solvent explored herein creates the required hierarchical micro/nanostructures. The hydrophobic modification of the β-HPG hydrated samples exhibite long-term mechanical strength. Abstract: Gypsum is a typical healthful, eco-type, and energy-saving material. However, because of poor water resistance, its applications were limited. Therefore, this paper reports on a one-step stoichiometry-controlled reaction method for the preparation of long-chain silicones based on micro/nano-layered siloxane aggregates generated in a low-cost solvent. In this study, self-assembled monolayers of octadecyltrichlorosilane were prepared on the surface of β-hemihydrate phosphogypsum (β-HPG) samples using n -hexane and dichloroethane, tested for contact angle, mechanical properties, softening coefficient, analysed for hydrophobicity and durability. The results show that the water droplet surface is stable with a maximum contact angle of 144.70 ± 1.1°, the softening coefficient is 0.92 and the water absorption rate is reduced to 1.1 %. The surface remained well hydrophobic when rubbed 12 times with 600 grit sandpaper under a pressure of 4.4 KPa. The above results show that this hydrophobic coating has a promising application in the protection of large gypsum products.