scholarly journals Fabrication and Biodegradability of Starch Cell-Plastics as Recyclable Resources

2021 ◽  
Vol 11 (2) ◽  
pp. 847
Author(s):  
Akihito Nakanishi ◽  
Kohei Iritani ◽  
Yuri Sakihama ◽  
Marina Watanabe ◽  
Ayano Mochiduki ◽  
...  
Keyword(s):  
Water Resistance ◽  
Water Environment ◽  
Water Repellency ◽  
Surface Structures ◽  
Water Repellent ◽  
Raw Starch ◽  
Oxidized Starch ◽  
Green Algal ◽  
Recyclable Resources ◽  
Phosphate Buffered Saline

Recently, cell-plastics, which are composed of unicellular green algal cells and biodegradable compounds as ingredients and fillers, have been suggested as carbon-recyclable materials instead of petroleum-based plastics. In this study, cell-plastics, fabricated with Chlamydomonas reinhardtii as an ingredient and a mixture of two types of starches (raw and oxidized starches) as a filler, were successfully stabilized as independent structures despite the quantity of algal cells being nine times more than that of starch. All starch cell-plastics were water repellent, possibly due to their bumpy surface structures. The starch cell-plastic, composed of 50% cells and 50% starch (1.5:1 of oxidized starch versus raw starch), showed 327 ± 52 MPa as Young’s modulus and 6.45 ± 1.20 MPa as tensile strength, indicating the possibility to be a suitable replacement for petroleum-based plastics. Additionally, all starch cell-plastics showed water-repellency and maintained those structures dipped in phosphate-buffered saline buffer as a water environment for 24 h, meaning that all starch cell-plastics had evaluable water resistance. On the other hand, by adding α-amylase, all starch cell-plastics were collapsed and lost the weight efficiently, indicated their biodegradability. This is the first paper to describe starch cell-plastics from their fabrication to biodegradation.

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.

scholarly journals Multi-layered Breathable Fabric Structures with Enhanced Water Resistance

2012 ◽  
Vol 7 (4) ◽  
pp. 155892501200700 ◽  
Author(s):  
Ilhan Ozen
Keyword(s):  
Water Resistance ◽  
Construction Materials ◽  
Water Vapor Permeability ◽  
Water Repellency ◽  
Water Repellent ◽  
Vapor Permeability ◽  
Pressure Water ◽  
Breathable Fabric ◽  
Fabric Structures ◽  
Microporous Film

This work reports waterproof breathable layered fabrics consisting of simple fabric weave types (plain, twill) and microporous breathable films. The pretreated fabrics were treated with water-repellent finishing chemicals. Afterwards, layered structures were generated by bringing the fabrics and the microporous breathable films together. According to the results of water repellency, hydrostatic pressure (water resistancy) and water vapor permeability tests conducted on the samples with/without microporous film layers, waterproof breathable layered fabrics were able to be generated, which are supposed to be used as construction materials.

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.

Preparation and Water Resistance of the New Water Epellent Agent of Paper Lunch Boxes

2011 ◽  
Vol 236-238 ◽  
pp. 1199-1202
Author(s):  
Shu Fang Zhou ◽  
Chuan Shan Zhao ◽  
Jing Jing Wang
Keyword(s):  
Contact Angle ◽  
Water Resistance ◽  
Dry Weight ◽  
Water Repellent ◽  
Optimal Conditions ◽  
Mass Ratio ◽  
Domestic Water ◽  
Oil Resistance ◽  
Effect Of Water

In this paper, a kind of sizing synergist,AKD,cationic rosin(CRS) and oil resistance agent were mixed in different proportions, we make it as a kind of new water repellent agent ,and for internal sizing. The best dosage and the composite ratio of the synergist, AKD, cationic rosin and oil resistance agent was discussed mainly in this experiment. And then the copy paper were tested of the substanceweight and contact angle, and compared with the water resistance when the domestic water repellent agent or AKD was added alone. Conclusions of this experiment are following: the optimal conditions were that the mass ratio of AKD and CRS is 6:4, the additive level of AKD and the cationic rosin is 6% (based on dry weight of pulp), the quantity of the sizing synergist is 0.5% , and no oil resistance agent was added, the effect of water resistance is best.

scholarly journals Superhydrophobic surfaces

2012 ◽  
Vol 21 (1-2) ◽  
pp. 21-32 ◽  
Author(s):  
Ioannis Karapanagiotis ◽  
Panagiotis Manoudis
Keyword(s):  
Water Repellency ◽  
Superhydrophobic Surfaces ◽  
Water Repellent ◽  
Baxter Equation ◽  
Feature Article ◽  
Surface Protection ◽  
Recent Developments ◽  
Potential Applications ◽  
Nanoparticle Composites ◽  
Potential Use

AbstractSuperhydrophobicity – also known as water repellency – has recently attracted considerable attention because of its numerous potential applications. However, the fundamental concepts and equations describing the wettability of superhydrophobic surfaces have been known since the 1940s. These concepts are reviewed and discussed in the present feature article in light of the recent developments. Furthermore, the potential use of water-repellent siloxane-nanoparticle composites for surface protection and consolidation of stones and mortars used in outdoor objects of cultural heritage is investigated. Finally, it is shown that the wettability of the composite surfaces can be predicted by the Cassie-Baxter equation.

scholarly journals Water-Repellent Fluoropolymer-Based Coatings

Coatings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 293 ◽  
Author(s):  
Paz-Gómez ◽  
Caño-Ochoa ◽  
Rodríguez-Alabanda ◽  
Romero ◽  
Cabrerizo-Vílchez ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Surface Texturing ◽  
Environmental Scanning Electron Microscopy ◽  
Water Repellency ◽  
Environmental Scanning ◽  
Water Repellent ◽  
Current Development ◽  
Laser Patterning ◽  
Water Drops ◽  
Scanning Electron

Fluoropolymer-based coatings are widely used for release applications. However, these hydrophobic surfaces do not reveal a significantly low adhesion. Water repellency incorporated to fluoropolymer coatings might enhance their release performance. In this work, we focused on the surface texturing of a well-known polytetrafluoroethylene (PTFE)-based coating. We explored as texturing routes: sanding, sandblasting and laser ablation. We examined the surface roughness with white light confocal microscopy and the surface morphology with environmental scanning electron microscopy (ESEM). Water-repellent fluoropolymer coatings were reproduced in all cases, although with different degree, parametrized with bounces of water drops (4–5 μL). Laser ablation enabled the lowest adhesion of coatings with 24 ± 2 bounces. This result and the current development of laser patterning for industry assure the incipient use of laser ablation for release coatings.

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