scholarly journals The Puncture and Water Resistance of Polyurethane- Impregnated Fabrics after UV Weathering

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 15
Author(s):  
Antonella Patti ◽  
Domenico Acierno
Keyword(s):  
Experimental Data ◽  
Uv Radiation ◽  
Water Resistance ◽  
Uv Light ◽  
Crosslinking Agent ◽  
Waterborne Polyurethane ◽  
Impregnation Method ◽  
Polyurethane Dispersion ◽  
Spectroscopic Analyses ◽  
Before And After

Polyurethane is a polymer adaptable to different scientific and industrial requirements; nevertheless it is also extremely susceptible to UV radiation, which compromises the physical and mechanical functionality. In this framework, our study investigated the effect of waterborne polyurethane dispersion (WPUD) applied to a polyester (PET)-based fabric, through the impregnation method, on the puncturing and water resistance of the pristine material, before and after UV weathering. Results confirmed an increment of both features in the prepared fabrics, attributed to the PUR textile treatment; but a partially loss of the gained properties in the samples due to the UV weathering. In order to improve the efficiency of the impregnating dispersions, in protecting the durability of the treated materials, the addition of different UV light stabilizers, or/and of crosslinking agent into WPUD was also tested. From the experimental data, it can be concluded that formulations based on WPUD, containing both the crosslinker and UV organic absorber, have displayed an increment of their perforation and water resistance for the treated samples with respect to the starting textile, and contemporary have preserved the features against the UV light. Finally, microscopic and spectroscopic analyses have been performed as further characterization techniques of the samples surface.

scholarly journals Established an eco-friendly cotton fabric treating process with enhancing anti-wrinkle performance

2021 ◽  
Vol 16 ◽  
pp. 155892502110034
Author(s):  
Xiongfang Luo ◽  
Pei Cheng ◽  
Wencong Wang ◽  
Jiajia Fu ◽  
Weidong Gao
Keyword(s):  
Tensile Strength ◽  
Citric Acid ◽  
Cotton Fabric ◽  
Crosslinking Agent ◽  
Cost Effective ◽  
Waterborne Polyurethane ◽  
Cotton Fabrics ◽  
Wrinkle Resistance ◽  
Before And After ◽  
Strength Retention

This study establishes an eco-friendly anti-wrinkle treating process for cotton fabric. Sodium hydroxide-liquid ammonia pretreatment followed by 6% (w/w) PU100 adding citric acid pad-cure-dry finishing. In this process, citric acid (CA) was used as the fundamental crosslinking agent during finishing because it is a non-formaldehyde based, cost-effective and well wrinkle resistance agent. Environmental-friendly waterborne polyurethane (WPU) was used as an additive to add to the CA finishing solution. Six commercial WPUs were systematically investigated. Fabric properties like wrinkle resistance, tensile strength retention, whiteness, durable press, softness, and wettability were well investigated. Fourier transform infrared spectra and X-ray diffraction spectra were also measured and discussed before and after adding waterborne polyurethane. Tentative mechanism of the interaction among the WPU, CA, and modified cotton fabrics is provided. The effect of cotton fabric pretreatment on fabric performance was also investigated. After the eco-process’s treatment, the fabric wrinkle resistant angle was upgraded to 271 ± 7°, tensile strength retention was maintained at 66.77% ± 3.50% and CIE whiteness was elevated to 52.13 ± 3.21, which are much better than the traditional CA anti-wrinkle finishing based on mercerized cotton fabrics. This study provides useful information for textile researchers and engineers.

Improved Water Resistance of Waterborne Polyurethane

2010 ◽  
Vol 168-170 ◽  
pp. 1796-1800
Author(s):  
Sui Lian Luo ◽  
Guo Fei Gong ◽  
Jun Qiang Deng ◽  
Guang Shi ◽  
Hong Zhu
Keyword(s):  
Water Resistance ◽  
Uv Light ◽  
Uv Curing ◽  
Waterborne Polyurethane ◽  
Side Chain ◽  
Strength Increase ◽  
Application Time ◽  
Extension Agent ◽  
Polyurethane Resin ◽  
Tensile Strength Increase

The introduction of hydrophilic groups, such as -COOH, -SO3, -OH, -O-, into the polyurethane resin, so that waterborne polyurethane products in the water resistance, solvent resistance, weather and other aspects of performance are worse than solvent borne systems. In our work, to improve the water resistance of the films for waterborne polyurethane, we incorporated C=C bond into the side chain of polyurethane by using pentaerythritol diacrylate as an extension agent. By measuring the cured polyurethane films absorption and mechanical properties, we determine the conditions for UV curing, 3% TMPME, photoinitiator (2959) and to UV light application time for 30s. With the increase of the amount PEDA, water resistance, hardness and tensile strength increase. Furthermore, with the improved water resistance, it is hoped that the performance of waterborne polyurethane can be comparative or superior to the solvent-borne systems.

Investigation of Hyperbranced Polyesters with Different Generation and their Application in Waterborne Polyurethanes

2012 ◽  
Vol 152-154 ◽  
pp. 91-96 ◽  
Author(s):  
Dong Ya Yang ◽  
Li Han ◽  
Han Qing Zhang ◽  
Feng Xian Qiu
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Crosslinking Agent ◽  
Waterborne Polyurethane ◽  
Hyperbranched Polyester ◽  
Aqueous Dispersions ◽  
Hyperbranched Polyesters ◽  
Waterborne Polyurethanes ◽  
Lower Viscosity ◽  
Polyurethane Dispersions

The 1st, 2nd and 3rd generations of hydroxyl-terminated hyperbranched polyesters (HBPE-1, HBPE-2, and HBPE-3) were synthesized. A3rd generation hyperbranched polyester (HBPE-3) was used as original crosslinking agent to prepared hyperbranched waterborne polyurethane dispersions (HPU). FTIR spectra confirmed that this reaction really took place. The experimental data indicated that, compared with the linear one, the hyperbranched HPU aqueous dispersions exhibited lower viscosity, and larger particle size. For the hyperbranched HPU films, mechanical properties were obviously enhanced.

Sorbitol enhances the physicochemical stability of B12 vitamers

2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot
Keyword(s):  
Ascorbic Acid ◽  
Uv Light ◽  
Heat Exposure ◽  
Water Soluble ◽  
Uv Exposure ◽  
Physicochemical Stability ◽  
Before And After ◽  
The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

UV Irradiation of Shell Eggs: Effect on Populations of Aerobes, Molds, and Inoculated Salmonella typhimurium

1997 ◽  
Vol 60 (6) ◽  
pp. 639-643 ◽  
Author(s):  
FUENG-LIN KUO ◽  
JOHN B. CAREY ◽  
STEVEN C. RICKE
Keyword(s):  
Salmonella Typhimurium ◽  
Uv Radiation ◽  
Uv Light ◽  
The Other ◽  
Uv Exposure ◽  
Microbial Populations ◽  
Aerobic Bacteria ◽  
Fluorescent Light ◽  
Uv Treatment ◽  
Shell Eggs

The effects were investigated of 254-nm UV radiation on populations of Salmonella typhimurium, aerobes, and molds on the shells of eggs. In the first experiment, the CFU of attached S. typhimurium cells on unwashed clean shell eggs were determined after 0, 1, 3, 5, and 7 min of UV treatment (620 μW/cm2) on both ends of the egg. All UV treatments significantly reduced S. typhimurium CFU (P &lt; .01). UVtreatment (620 μW/cm2) in 1-min alternating light and dark cycles for 5 min (three light and two dark) was compared to 0, 3, and 5 min of UV treatment. No significant differences in microbial populations were observed among light and dark cycles and the other UV treatments. In a subsequent experiment, the same UV treatments were utilized to evaluate photoreactivation. After UV exposure, eggs were exposed to 1 h of fluorescent light or I h of darkness or cultured immediately. S. typhimurium CFU were significantly (P &lt; .01) reduced by the UV treatments. However, no significant differences between microbial populations exposed to UV treatment and UV radiation plus photoreactivation were detected. For studies of aerobic bacteria and molds, different UV treatment times (0, 15, and 30 min) at the intensity of 620 μW/cm2 and different intensities (620, 1350, and 1720 μW/cm2) for 15 min were evaluated. Mold CFU per egg were either 0 or 1 for all UV treatments and a 99% reduction of CFU of aerobic bacteria per egg were observed for all UV treatments. It appears from these studies that UV light can significantly reduce populations of S. typhimurium, aerobes, and molds on shell eggs.

scholarly journals Study of the Ultraviolet Effect and Thermal Analysis on Polypropylene Nonwoven Geotextile

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1080
Author(s):  
Clever Aparecido Valentin ◽  
Marcelo Kobelnik ◽  
Yara Barbosa Franco ◽  
Fernando Luiz Lavoie ◽  
Jefferson Lins da Silva ◽  
...  
Keyword(s):  
Uv Light ◽  
Polymeric Materials ◽  
Tensile Tests ◽  
Thermomechanical Analysis ◽  
Material Stiffness ◽  
Before And After ◽  
Electron Microscopy Analysis ◽  
Physical Tests ◽  
Nonwoven Geotextile

The use of polymeric materials such as geosynthetics in infrastructure works has been increasing over the last decades, as they bring down costs and provide long-term benefits. However, the aging of polymers raises the question of its long-term durability and for this reason researchers have been studying a sort of techniques to search for the required renewal time. This paper examined a commercial polypropylene (PP) nonwoven geotextile before and after 500 h and 1000 h exposure to ultraviolet (UV) light by performing laboratory accelerated ultraviolet-aging tests. The state of the polymeric material after UV exposure was studied through a wide set of tests, including mechanical and physical tests and thermoanalytical tests and scanning electron microscopy analysis. The calorimetric evaluations (DSC) showed distinct behaviors in sample melting points, attributed to the UV radiation effect on the aged samples. Furthermore, after exposure, the samples presented low thermal stability in the thermomechanical analysis (TMA), with a continuing decrease in their thicknesses. The tensile tests showed an increase in material stiffness after exposition. This study demonstrates that UV aging has effects on the properties of the polypropylene polymer.

MICROSTRUCTURE ANALYSIS OF MOSO BAMBOO (Phyllostachys pubescens MAZEL) SURFACE AFTER UV RADIATION

2019 ◽  
Vol 27 (01) ◽  
pp. 1950090
Author(s):  
HAIXIA YU ◽  
XIN PAN ◽  
WEIMING YANG ◽  
WENFU ZHANG ◽  
XIAOWEI ZHUANG
Keyword(s):  
Uv Radiation ◽  
Cell Walls ◽  
Uv Light ◽  
Parenchyma Cell ◽  
Moso Bamboo ◽  
Thick Wall ◽  
Phyllostachys Pubescens ◽  
Thin Wall ◽  
Intercellular Spaces ◽  
Parenchyma Cell Walls

Bamboo material is widely used in outdoor applications. However, they are easily degraded when exposed to sunlight, their smooth surface will gradually turn to rough, and small cracks will appear and finally develop to large cracks. The paper presents a first-time investigation on the microstructure changes in the tangential section of Moso bamboo (Phyllostachys pubescens Mazel) radiated by artificial UV light. The results showed that the cracks mainly appeared at intercellular spaces of fibers where lignin content was high, the parenchyma cell walls and neighbor pits where the cell wall was very thin and more vulnerable than the other parts. In addition, the part of raised area and pit cavity tended to absorb more UV light radiation and showed more and larger cracks than the otherwhere. Cracks at the intercellular spaces of fibers were larger and bigger than those on the parenchyma cell walls. The cracks on the pits of the parenchyma cell walls normally appeared at one pit and then extended to the several surrounding pits. Bordered pits cavity showed more and larger cracks than the pits on the thin wall cells. The simple pits on the thick wall cells and the fiber cells were unaffected by UV radiation.

Effect of crystalline structure on water resistance of waterborne polyurethane

2021 ◽  
pp. 110647
Author(s):  
Zhengkai Wei ◽  
Zhimeng Liu ◽  
Xiaowei Fu ◽  
Yuechuan Wang ◽  
Anqian Yuan ◽  
...  
Keyword(s):  
Crystalline Structure ◽  
Water Resistance ◽  
Waterborne Polyurethane

Psychophysical interactions with a double-slit interference pattern: Exploratory evidence of a causal influence

2021 ◽  
Vol 34 (1) ◽  
pp. 79-88
Author(s):  
Dean Radin ◽  
Helané Wahbeh ◽  
Leena Michel ◽  
Arnaud Delorme
Keyword(s):  
Experimental Data ◽  
Interference Pattern ◽  
Type I Error ◽  
Human Mind ◽  
The Other ◽  
Type I ◽  
Fringe Visibility ◽  
Future Studies ◽  
Before And After ◽  
Double Slit

An experiment we conducted from 2012 to 2013, which had not been previously reported, was designed to explore possible psychophysical effects resulting from the interaction of a human mind with a quantum system. Participants focused their attention toward or away from the slits in a double-slit optical system to see if the interference pattern would be affected. Data were collected from 25 people in individual half-hour sessions; each person repeated the test ten times for a total of 250 planned sessions. “Sham” sessions designed to mimic the experimental sessions without observers present were run immediately before and after as controls. Based on the planned analysis, no evidence for a psychophysical effect was found. Because this experiment differed in two essential ways from similar, previously reported double-slit experiments, two exploratory analyses were developed, one based on a simple spectral analysis of the interference pattern and the other based on fringe visibility. For the experimental data, the outcome supported a pattern of results predicted by a causal psychophysical effect, with the spectral metric resulting in a 3.4 sigma effect (p = 0.0003), and the fringe visibility metric resulting in 7 of 22 fringes tested above 2.3 sigma after adjustment for type I error inflation, with one of those fringes at 4.3 sigma above chance (p = 0.00001). The same analyses applied to the sham data showed uniformly null outcomes. Other analyses exploring the potential that these results were due to mundane artifacts, such as fluctuations in temperature or vibration, showed no evidence of such influences. Future studies using the same protocols and analytical methods will be required to determine if these exploratory results are idiosyncratic or reflect a genuine psychophysical influence.

scholarly journals Study of the Response of a Biofilm Bacterial Community to UV Radiation

1999 ◽  
Vol 65 (5) ◽  
pp. 2025-2031 ◽  
Author(s):  
Mohamed O. Elasri ◽  
Robert V. Miller
Keyword(s):  
Uv Radiation ◽  
Protective Property ◽  
Uv Light ◽  
Planktonic Cells ◽  
Light Production ◽  
Whole Cell Biosensor ◽  
Uv C ◽  
Cell Biosensor ◽  
Biofilm Matrix ◽  
Alginate Matrix

ABSTRACT We have developed a bioluminescent whole-cell biosensor that can be incorporated into biofilm ecosystems. RM4440 is a Pseudomonas aeruginosa FRD1 derivative that carries a plasmid-basedrecA-luxCDABE fusion. We immobilized RM4440 in an alginate matrix to simulate a biofilm, and we studied its response to UV radiation damage. The biofilm showed a protective property by physical shielding against UV C, UV B, and UV A. Absorption of UV light by the alginate matrix translated into a higher survival rate than observed with planktonic cells at similar input fluences. UV A was shown to be effectively blocked by the biofilm matrix and to have no detectable effects on cells contained in the biofilm. However, in the presence of photosensitizers (i.e., psoralen), UV A was effective in inducing light production and cell death. RM4440 has proved to be a useful tool to study microbial communities in a noninvasive manner.

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