scholarly journals Novel waterborne polyurethanes containing long-chain alkanes: their synthesis and application to water repellency

RSC Advances ◽  
2019 ◽  
Vol 9 (54) ◽  
pp. 31357-31369 ◽  
Author(s):  
Xiaoli Liu ◽  
Xiaobin Zou ◽  
Zhen Ge ◽  
Wenguo Zhang ◽  
Yunjun Luo
Keyword(s):  
Free Water ◽  
Water Repellency ◽  
Water Repellent ◽  
Waterborne Polyurethanes ◽  
Water Repellents ◽  
Long Chain ◽  
Fabric Finishing

In the fabric finishing field, the water repellents have received increasing interest in recent years and the development of a fluorine-free water repellent has become an attractive prospect.

scholarly journals Synthesis of a Novel Linear α, ω-Di (Chloro Phosphoramide) Polydimethylsiloxane and Its Applications in Improving Flame-Retardant and Water-Repellent Properties of Cotton Fabrics

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1829 ◽  
Author(s):  
Chaohong Dong ◽  
Ling Sun ◽  
Xingbo Ma ◽  
Zhou Lu ◽  
Pengshuang He ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Flame Retardancy ◽  
Free Water ◽  
Water Repellency ◽  
Cotton Fabrics ◽  
Water Repellent ◽  
Cone Calorimetry ◽  
Limiting Oxygen Index ◽  
Washing Durability ◽  
Char Length

A novel linear α, ω-di (chloro phosphoramide)-terminated polydimethylsiloxane (CPN-PDMS) was successfully synthesized and utilized as a formaldehyde-free water-repellent and flame-retardant for cotton fabrics. The flame retardancy of treated cotton fabrics was estimated by limiting oxygen index (LOI) test, vertical flammability test, and cone calorimetry test. The cotton fabrics treated with 350 g/L CPN-PDMS obtained excellent flame retardancy with an LOI value of 30.6% and the char length was only 4.3 cm. Combustion residues were studied using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) analysis. Results show that CPN-PDMS can effectively enhance water repellency and fire resistance of cotton fabrics. Furthermore, the breaking strength test and the whiteness test strongly prove that the tensile strength and whiteness of the treated cotton fabrics were slightly lower than that of the pure cotton fabrics. The wash stability test showed that after 30 laundering cycles, the treated cotton fabrics still had an LOI value of 28.5% and a water-repellent effect of grade 80, indicating that CPN-PDMS was an excellent washing durability additive. In summary, these property enhancements of treated cotton fabrics were attributed to the synergistic effect of silicon-phosphorus-nitrogen elements in CPN-PDMS.

scholarly journals Preparation and Application of Fluorine-Free Finishing Agent with Excellent Water Repellency for Cotton Fabric

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2980
Author(s):  
Chengbing Yu ◽  
Kaiqin Shi ◽  
Jinyan Ning ◽  
Zhe Zheng ◽  
Hualong Yu ◽  
...  
Keyword(s):  
Cotton Fabric ◽  
Structural Characteristics ◽  
Silicon Film ◽  
Free Water ◽  
Water Repellency ◽  
Water Repellent ◽  
Good Resistance ◽  
Multi Scale ◽  
Xps Characterization ◽  
Finishing Agent

Water repellent is an important functional finish for cotton fabric. However, cotton fabrics often have poor washing resistance and other performances after actual finishing. In this study, based on the structural characteristics of cotton fiber and durability of water repellent, a cross-linked amino long-chain alkyl polysiloxane (CAHPS) was first prepared, and then reacted with modified silica. Finally, a chemically bonded organic–inorganic nanohybrid cross-linked polysiloxane (rSiO2-CAHPS) was fabricated. Furthermore, the rSiO2-CAHPS was emulsified to obtain a durable fluorine-free water repellent. The water repellent finishing for cotton fabric was carried out by the pad–dry–cure process. After finishing, the cotton fabric had good resistance to conventional liquids and excellent washing resistance, and still maintained good water repellency after 30 rounds of soaping. Moreover, properties including air permeability, mechanical property and whiteness are hardly affected after finishing. SEM and XPS characterization show that a layer of dense silicon film is formed on the surface of cotton fabric by rSiO2-CAHPS water repellent. The existence of nanosilica can improve the surface roughness of cotton fibers. The synergistic effect of fiber matrix, nanoparticles and CAHPS endows the fabric with a micro/nano-multi-scale micro-rough structure, which improves the water repellency of cotton fabric after water repellent finishing.

Non-adhesive lotus and other hydrophobic materials

2008 ◽  
Vol 366 (1870) ◽  
pp. 1539-1556 ◽  
Author(s):  
David Quéré ◽  
Mathilde Reyssat
Keyword(s):  
Solid Surface ◽  
Room Temperature ◽  
Water Repellency ◽  
Short Review ◽  
Water Repellent ◽  
Practical Applications ◽  
Hydrophobic Materials ◽  
Volatile Liquid ◽  
Air Cushion ◽  
The Stability

Superhydrophobic materials recently attracted a lot of attention, owing to the potential practical applications of such surfaces—they literally repel water, which hardly sticks to them, bounces off after an impact and slips on them. In this short review, we describe how water repellency arises from the presence of hydrophobic microstructures at the solid surface. A drop deposited on such a substrate can float above the textures, mimicking at room temperature what happens on very hot plates; then, a vapour layer comes between the solid and the volatile liquid, as described long ago by Leidenfrost. We present several examples of superhydrophobic materials (either natural or synthetic), and stress more particularly the stability of the air cushion—the liquid could also penetrate the textures, inducing a very different wetting state, much more sticky, due to the possibility of pinning on the numerous defects. This description allows us to discuss (in quite a preliminary way) the optimal design to be given to a solid surface to make it robustly water repellent.

Performance Study of Nano-TiO2 Modified Fabric

2012 ◽  
Vol 549 ◽  
pp. 733-736
Author(s):  
Xiao Mian Chen ◽  
Jing Jing Shi ◽  
Hong Sha Su ◽  
Chun Ting Lin ◽  
En Long Yang
Keyword(s):  
Titanium Dioxide ◽  
Catalytic Activity ◽  
Catalytic Properties ◽  
Antibacterial Property ◽  
Wear Behavior ◽  
Water Repellency ◽  
Innovative Technology ◽  
Water Repellent ◽  
High Catalytic Activity ◽  
Performance Study

The catalytic properties of nano-TiO2 modified fabric suits the demand for self-cleaning in recent years. In this paper, advanced and innovative technology were used to synthesize water sol of titanium dioxide photocatalyst with high catalytic activity for fabric finishing. The wear behavior, antibacterial property and water repellency of treated and untreated fabric were tested. Results indicate that finishing and washing of the titanium dioxide had no effect on wear behavior; finished and washed fabric has a certain antibacterial and water repellent properties.

scholarly journals Water repellency of clay, sand and organic soils in Finland

2008 ◽  
Vol 16 (3) ◽  
pp. 267 ◽  
Author(s):  
K. RASA ◽  
R. HORN ◽  
M. RÄTY
Keyword(s):  
Preferential Flow ◽  
Management Practice ◽  
Soil Surface ◽  
Water Repellency ◽  
Organic Soil ◽  
Water Infiltration ◽  
Organic Soils ◽  
Water Repellent ◽  
Moisture Regime ◽  
Wetting Process

Water repellency (WR) delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95) at the time of sampling. WR increased as follows: sand (R = 1.8-5.0) < clay (R = 2.4-10.3) < organic (R = 7.9-undefined). At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr.), where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.;

scholarly journals Spatially variable soil water repellency enhances soil respiration rates (CO<sub>2</sub> efflux)

2017 ◽  
Author(s):  
Emilia Urbanek ◽  
Stefan H. Doerr
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Water ◽  
Water Distribution ◽  
Preferential Flow ◽  
Water Repellency ◽  
Water Repellent ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil Water Repellency

Abstract. Soil CO2 emissions are strongly dependent on water distribution in soil pores, which in turn can be affected by soil water repellency (SWR; hydrophobicity). SWR restricts infiltration and movement of water, affecting soil hydrology as well as biological and chemical processes. Effects of SWR on soil carbon dynamics and specifically on soil respiration (CO2 efflux) have been studied in a few laboratory experiments but they remain poorly understood. Existing studies suggest that soil respiration is reduced in water repellent soils, but the responses of soil CO2 efflux to varying water distribution created by SWR are not yet known. Here we report on the first field-based study that tests whether soil water repellency indeed reduces soil respiration, based on in situ field measurements carried out over three consecutive years at a grassland and pine forest site under the humid temperate climate of the UK. CO2 efflux was reduced on occasions when soil exhibited consistently high SWR and low soil moisture following long dry spells. However, the highest respiration rates occurred not when SWR was absent, but when SWR, and thus soil moisture, was spatially patchy, a pattern observed for the majority of the measurement period. This somewhat surprising phenomenon can be explained by SWR-induced preferential flow, directing water and nutrients to microorganisms decomposing organic matter concentrated in hot spots near preferential flow paths. Water repellent zones provide air-filled pathways through the soil, which facilitate soil-atmosphere O2 and CO2 exchanges. This study demonstrates that SWR have contrasting effects on CO2 fluxes and, when spatially-variable, can enhance CO2 efflux. Spatial variability in SWR and associated soil moisture distribution needs to be considered when evaluating the effects of SWR on soil carbon dynamics under current and predicted future climatic conditions.

scholarly journals Engineering Properties of Foamed Concrete Containing Water Repellent

2018 ◽  
Vol 65 ◽  
pp. 02005 ◽  
Author(s):  
Yee Ling Lee ◽  
Chen Hoe Oh ◽  
Ming Han Lim ◽  
Foo Wei Lee
Keyword(s):  
Construction Industry ◽  
Vital Role ◽  
Engineering Properties ◽  
Water Repellent ◽  
Initial Surface ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Foamed Concrete ◽  
Optimum Water ◽  
Water Repellents

Concrete plays a vital role in the construction industry. Over the years, increasing demands from the construction industry had led to the birth of various types of concrete. Foamed concrete is one of the variations of lightweight concrete and yields a high percentage of porosity due to the internal presence of multiple air bubbles. Consequently, foamed concrete is prone to harmful substances’ penetration, which will disrupt its overall durability and the purpose of usage. Hence, water repellent is introduced into foamed concrete in this study and its effect on various engineering properties of foamed concrete will be investigated. The objectives of this study are to obtain optimum water-to-cement ratio for the 1200 kg/m3 foamed concrete and to study the impacts of water repellents on the fresh and engineering properties of foamed concrete. This study was separated into two main research phases. The first phase aimed at determining the optimum water-to-cement ratio for foamed concrete without the presence of water repellents, which was then determined as 0.48. The continuation of this research exhibited the utilization of the obtained optimum water-to-cement ratio from the first phase of the study to delve into the impact analysis of 0.2% and 0.4% calcium stearate (CS) on the fresh and engineering properties of foamed concrete. The incorporation of CS into foamed concrete had affected its mechanical properties in terms of compressive strength. However, it had played a vital role in improving the foamed concrete’s physical properties in terms of absorption, initial surface absorption and sorptivity. It was also found that the recommended dosage for CS incorporation was determined as 0.2% of cement weight as to prevent the adverse effects from overdosing of water repellents.

Preparation and properties of waterborne polyurethane modified by aminoethylaminopropyl polydimethylsiloxane for fluorine-free water repellents

2020 ◽  
Vol 139 ◽  
pp. 105407 ◽  
Author(s):  
Wenguo Zhang ◽  
Xiaobin Zou ◽  
Xiaoli Liu ◽  
Zhu Liang ◽  
Zhen Ge ◽  
...  
Keyword(s):  
Free Water ◽  
Waterborne Polyurethane ◽  
Water Repellents

Investigation of sewing and water repellent performance of outdoor clothing

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yaşar Erayman Yüksel ◽  
Yasemin Korkmaz
Keyword(s):  
Design Methodology ◽  
Water Resistance ◽  
Water Repellency ◽  
Woven Fabrics ◽  
Water Repellent ◽  
Content Type ◽  
Textile Materials ◽  
Sewing Threads ◽  
Reduced Water ◽  
Seam Pucker

Purpose Durability of textile materials under wet conditions has become very important in recent years. The water repellency performance of fabrics should be maintained in the seam areas. The purpose of this paper is to analyze the effect of water repellent agents and sewing threads on the seam and water repellency performance properties of woven fabrics. Design/methodology/approach 100 percent polyester woven fabrics were treated with three different water repellent finishing agents (silicone, fluorocarbons with 6 and 8 carbons) and then sewn with different sewing threads (unfinished/water repellent finished polyester/cotton corespun and polyamide filament). Afterwards, mechanical properties, seam performance and water repellency properties of these materials were measured. Findings The effect of finishing which was statistically significant on seam strength only in warp direction was significant on seam elongation and efficiency in both warp and weft directions. Seam strength, seam efficiency, seam slippage and seam pucker of fabrics sewn with polyamide threads were higher than others. The fluorocarbons applied to the fabrics gave higher water repellency values than silicones. In addition, as the chain length increased in fluorocarbons, water repellency performance increased. Sewing process reduced water resistance of fabrics; however, water repellent finish applied to the threads increased water resistance of fabrics. Originality/value As a result of the literature review, it was seen that water repellency property of a wear were studied in only seamless areas of fabrics. Originality of this study is that the water repellency properties are also analyzed in the seam areas of the fabrics and evaluated together with the seam performance characteristics.

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