Search results
1 – 10 of 43F.A. Abdel‐Mohdy, A. Waly, A. Higazy and A. Hebeish
Perfluoroheptyl methacrylate was copolymerized with acrylamide using different ratios of these monomers. The copolymers so obtained were methylolated with formaldehyde. The…
Abstract
Perfluoroheptyl methacrylate was copolymerized with acrylamide using different ratios of these monomers. The copolymers so obtained were methylolated with formaldehyde. The methylolated copolymers were used as multi‐purpose finishing agents for cotton. They impart oil and water repellence. Attachment of the methylolated copolymer to cotton is presumed to involve chemical bonds via reaction of the methylol groups of the copolymer and the hydroxy groups of cotton cellulose. This was evidenced by the wash‐fastness properties; no significant differences were noted in the oil/water repellence of cotton fabric treated with the copolymers in question.
Chao-xia Wang, Mao Li, Guang-wei Jiang, Kuan-jun Fang and An-li An-li
The cotton fabrics were surface modified for water repellent finishing with silicon sol, which was prepared with the tetraethoxysilane(TEOS) and solvent ethanol, catalyzer HCl…
Abstract
The cotton fabrics were surface modified for water repellent finishing with silicon sol, which was prepared with the tetraethoxysilane(TEOS) and solvent ethanol, catalyzer HCl, water and modified with additives, such as Methyltriethoxysilane(MTEOS), Octyltriethoxysilane(OTEOS) and Hexadec-ltrimethoxysilane(HTEOS). As a result, acceptable water repellence could only be achieved via the addition of longer chain length additives such as OTEOS, HTEOS, while the use of additives containing a shorter alkyl chain length such as MTES led to insufficient water repellence. The factors which influence contact angles were examined. Excellent water repellent properties could be achieved on the cotton fabrics treated with the silica sols by twice dip and pad and cured at 160°. The silica sol preparation preference conditions were with TEOS: H2O: EtOH=1: 5: 8 (mol) by stirring for 6 hours at 65°C which was added with HTEOS. The water repellence contact angle was able to be reached around 140° and the hydrostatic pressure was 46cm.
Details
Keywords
Xiaohu Wen, Xiangkang Cao, Xiao-ze Ma, Zefan Zhang and Zehua Dong
The purpose of this paper was to prepare a ternary hierarchical rough particle to accelerate the anti-corrosive design for coastal concrete infrastructures.
Abstract
Purpose
The purpose of this paper was to prepare a ternary hierarchical rough particle to accelerate the anti-corrosive design for coastal concrete infrastructures.
Design/methodology/approach
A kind of micro-nano hydrophobic ternary microparticles was fabricated from SiO2/halloysite nanotubes (HNTs) and recycled concrete powders (RCPs), which was then mixed with sodium silicate and silane to form an inorganic slurry. The slurry was further sprayed on the concrete surface to construct a superhydrophobic coating (SHC). Transmission electron microscopy and energy-dispersive X-ray spectroscopy mappings demonstrate that the nano-sized SiO2 has been grafted on the sub-micron HNTs and then further adhered to the surface of micro-sized RCP, forming a kind of superhydrophobic particles (SiO2/HNTs@RCP) featured of abundant micro-nano hierarchical structures.
Findings
The SHC surface presents excellent superhydrophobicity with the water contact angle >156°. Electrochemical tests indicate that the corrosion rate of mild steel rebar in coated concrete reduces three-order magnitudes relative to the uncoated one in 3.5% NaCl solution. Water uptake and chloride ion (Cl-) diffusion tests show that the SHC exhibits high H2O and Cl- ions barrier properties thanks to the pore-sealing and water-repellence properties of SiO2/HNTs@RCP particles. Furthermore, the SHC possesses considerable mechanical durability and outstanding self-cleaning ability.
Originality/value
SHC inhibits water uptake, Cl- diffusion and rebar corrosion of concrete, which will promote the sustainable application of concrete waste in anti-corrosive concrete projects.
Details
Keywords
The objective of this study is to evaluate the water repellent efficiency of some oil modified solvent‐type alkyd resins, as wood protective formulations (WPs). It was done by…
Abstract
Purpose
The objective of this study is to evaluate the water repellent efficiency of some oil modified solvent‐type alkyd resins, as wood protective formulations (WPs). It was done by surface treating of pine and cedar woods with the five leading brand of alkyd resins that are available in Turkey.
Design/methodology/approach
For effective water repellency, various formulations were made by incorporating different concentrations of varnish resin, pigment, solvent, and a substance that repels water. The impact and adhesive strengths of the five different solvent‐type alkyd resins were characterised by using a very simple experimental design.
Findings
The swelling variations of unmodified pine and cedar woods were determined in water. Next, the water repellent efficiency of the five different alkyd resin formulations was evaluated. The modification of pine and cedar woods using alkyd resins showed various level enhancement of resistance against water over the unmodified samples. The modification caused a chemical linkage between surface and resin that led to ensuring the intrinsically chemical bonds across the wood/resin matrix interface, which was the main cause to the improved water resistance. However, some WPs were less compatible, hence, had less bonding potential to both woods.
Practical implications
The method developed provided a simple and practical solution to selecting WPs (brands) for pine and cedar woods.
Originality/value
The method for evaluating adhesive strengths of the five different brand solvent‐type alkyd resins to pine and cedar woods were novel and could find numerous applications in surface coating.
Details
Keywords
Chin How (Norman) Goh, Michael D. Short, Nanthi S. Bolan and Christopher P. Saint
Biosolids, the residual solids from wastewater treatment operations and once considered a waste product by the industry, are now becoming increasingly recognised as a…
Abstract
Biosolids, the residual solids from wastewater treatment operations and once considered a waste product by the industry, are now becoming increasingly recognised as a multifunctional resource with growing opportunities for marketable use. This shift in attitude towards biosolids management is spurred on by increasing volatility in energy, fertilizer and commodity markets as well as moves by the global community towards mitigating global warming and the effects of climate change. This chapter will provide an overview of current global biosolids practices (paired with a number of Australian examples) as well as discuss potential future uses of biosolids. Additionally, present and future risks and opportunities of biosolids use are highlighted, including potential policy implications.
Details
Keywords
Abstract
Details
Keywords
Abstract
Details
Keywords
Abstract
Details