scholarly journals Improvement of Water Resistance of Vegetable Proteins by the Use of Synthetic Origin Additives: Trials with Resins and Metal Ions

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 859
Author(s):  
Ilaria Santoni ◽  
Benedetto Pizzo
Keyword(s):  
Shear Strength ◽  
Metal Ions ◽  
Renewable Resources ◽  
Water Resistance ◽  
Curing Temperature ◽  
Insoluble Residue ◽  
Maturation Time ◽  
Strength Tests ◽  
Different Types ◽  
Positive Effect

The adhesives industry is increasingly interested in products coming from natural and renewable resources. The aim of the present work was to improve the water resistance of soy-based proteins by using synthetic and formaldehyde-free additives. These include polyamide-amine epichlorohydrin (PAE), different types of isocyanates, and combinations of these cross-linkers between them and with other agents, including metal ions. In addition, the effect of both curing temperature and maturation time was assessed. Performances were evaluated by means of shear strength tests, solubility tests, and spectroscopic analysis. The obtained results showed that while isocyanates reacted completely but with water instead of proteins, tests with PAE were generally successful. In fact, the insoluble residue as well as the shear strength in wet conditions dramatically increased after PAE addition. Moreover, the wet performances of protein/PAE formulations appreciably increased gluing at 60 °C instead of room temperature. Furthermore, the maturation time had a positive effect on the formulations where metal ions were added, both for solubility and wet shear strength. Actually, for the very long conditioning time of 3 months, a significant and substantial increase of wet shear strength was observed for the series protein/PAE/aluminum.

scholarly journals Influence of Single/Collective Use of Curing Agents on the Curing Behavior and Bond Strength of Soy Protein-Melamine-Urea-Formaldehyde (SMUF) Resin for Plywood Assembly

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1995 ◽  
Author(s):  
Zhigang Wu ◽  
Bengang Zhang ◽  
Xiaojian Zhou ◽  
Lifen Li ◽  
Liping Yu ◽  
...  
Keyword(s):  
Shear Strength ◽  
Water Resistance ◽  
Protein Hydrolysate ◽  
Soybean Protein ◽  
Urea Formaldehyde ◽  
Curing Temperature ◽  
Molar Ratio ◽  
Scanning Calorimetry ◽  
Curing Agents ◽  
Crosslinking Reactions

Soybean protein hydrolysate, melamine, urea, and concentrated formaldehyde were used to synthesize an environmentally friendly soybean protein-melamine-urea-formaldehyde (SMUF) co-condensation resin. (NH4)2SO4, (NH4)2HPO4, (NH4)2HPO4 + (NH4)2SO4, (NH4)2HPO4 + (NH4)2S2O8, and (NH4)2HPO4 + (NH4)2SO4 + (NH4)2S2O8 were employed as curing agents for SMUF resin. The curing and thermal behaviors of the SMUF resin were investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results revealed the following: (1) (NH4)2SO4 alone could not cure the SMUF resin completely; thus, the final shear strength accomplished plywood with the resin was low, and its water resistance was poor, while the adhesive section was loose and porous/brittle after curing. (2) (NH4)2HPO4 could be hydrolyzed to generate H+ and promote SMUF curing, but it could also form polyphosphoric acids, resulting in crosslinking reactions with SMUF in parallel; thereby, the curing properties were improved. (3) When (NH4)2HPO4 + (NH4)2SO4 + (NH4)2S2O8 were engaged collectively as curing agent, the shear strength, water resistance, and heat resistance of SMUF attained were the best possible whereas the curing temperature was decreased and the heat released by curing was elevated substantially, which signifies maximized extent of crosslinking was achieved. Further, the adhesive section exhibited mostly a crosslinking intertexture as demonstrated by means of SEM. Accordingly, this study may serve as a guide for the curing of amino resins, with low-molar ratio of formaldehyde to amine in adhesives, which are applied to plywood production.

Potential Uses of Vinegar as a Medicine and Related in vivo Mechanisms

2016 ◽  
Vol 86 (3-4) ◽  
pp. 127-151 ◽  
Author(s):  
Zeshan Ali ◽  
Zhenbin Wang ◽  
Rai Muhammad Amir ◽  
Shoaib Younas ◽  
Asif Wali ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Review Paper ◽  
Heart Diseases ◽  
Folk Medicine ◽  
Active Role ◽  
Current Review ◽  
Different Types ◽  
Positive Effect

While the use of vinegar to fi ght against infections and other crucial conditions dates back to Hippocrates, recent research has found that vinegar consumption has a positive effect on biomarkers for diabetes, cancer, and heart diseases. Different types of vinegar have been used in the world during different time periods. Vinegar is produced by a fermentation process. Foods with a high content of carbohydrates are a good source of vinegar. Review of the results of different studies performed on vinegar components reveals that the daily use of these components has a healthy impact on the physiological and chemical structure of the human body. During the era of Hippocrates, people used vinegar as a medicine to treat wounds, which means that vinegar is one of the ancient foods used as folk medicine. The purpose of the current review paper is to provide a detailed summary of the outcome of previous studies emphasizing the role of vinegar in treatment of different diseases both in acute and chronic conditions, its in vivo mechanism and the active role of different bacteria.

scholarly journals Chitosan-Based Adhesive: Optimization of Tensile Shear Strength in Dry and Wet Conditions

2021 ◽  
Vol 2 (1) ◽  
pp. 110-120
Author(s):  
Maisa Abdelmoula ◽  
Hajer Ben Hlima ◽  
Frédéric Michalet ◽  
Gérard Bourduche ◽  
Jean-Yves Chavant ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Shear Strength ◽  
Bond Strength ◽  
Water Resistance ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Spread Rate ◽  
Assembly Time ◽  
Deacetylation Degree ◽  
Dry And Wet Conditions

Commercial adhesives present a high bond strength and water resistance, but they are considered non-healthier products. Chitosan can be considered as an interesting biosourced and biodegradable alternative, despite its low water resistance. Here, its wood bonding implementation and its tensile shear strength in dry and wet conditions were investigated depending on its structural characteristics. Firstly, the spread rate, open assembly time, drying pressure, drying temperature, and drying time have been determined for two chitosans of European pine double lap specimens. An adhesive solution spread rate of 1000 g·m−2, an open assembly time of 10 min, and a pressure temperature of 55 °C for 105 min led to a bond strength of 2.82 MPa. Secondly, a comparison between a high molecular weight/low deacetylation degree chitosan and a lower molecular weight/higher deacetylation degree chitosan was conducted. Tests were conducted with beech simple lap specimens in accordance with the implementation conditions and the conditioning treatments in wet and dry environments required for thermoplastic wood adhesive standards used in non-structural applications (EN 204 and EN 205). The results clearly revealed the dependence of adhesive properties and water resistance on the structural features of chitosans (molecular weight and deacetylation degree), explaining the heterogeneity of results published notably in this field.

Nanocomposite Photocatalyst Based on Layered Double Hydroxides (LDHs) Associated with TiO2

2014 ◽  
Vol 92 ◽  
pp. 100-109 ◽  
Author(s):  
Jonjaua Ranogajec ◽  
Andrijana Sever-Skapin ◽  
Ognjen Rudic ◽  
Snezana Vucetic
Keyword(s):  
Photocatalytic Activity ◽  
Layered Double Hydroxides ◽  
Direct Contact ◽  
Building Materials ◽  
Specific Problem ◽  
The Self ◽  
Different Types ◽  
Double Hydroxides ◽  
Positive Effect ◽  
Material Porosity

The surfaces of building materials are constantly exposed to the actions of environmental factors, pollutants of inorganic and organic origin as well as to microorganisms, which significantly contribute to corrosion phenomena.The application of coatings decreases the negative action of the pollutants minimizing their direct contact with the substrate. Different types of coatings with additional functions have been developed. A specific problem of these applications is the lack of compatibility of the photocatalysts with the surface of the building materials and the detachment of potentially toxic TiO2nanoparticles. In the present study, this problem was solved by the proper immobilization of TiO2nanoparticles onto the photocatalyst support, layered double hydroxides (LDHs). The newly formed coating possesses acceptable porosity for a porous building material (porosity within the range of 30-46 %) and satisfied photocatalytic activity, as well as mineralogical compatibility with the substrates (mortars, renders, bricks). Additionally, a positive effect considering the self-cleaning phenomenon was attained.

Do Development and Democracy Positively Affect Gender Equality in Cabinets?

2015 ◽  
Vol 16 (3) ◽  
pp. 332-356 ◽  
Author(s):  
JOHN HÖGSTRÖM
Keyword(s):  
Economic Development ◽  
Gender Equality ◽  
Empirical Evidence ◽  
Comparative Studies ◽  
Developed Countries ◽  
Political Regimes ◽  
The World ◽  
Different Types ◽  
Negative Effect ◽  
Positive Effect

AbstractIt has been argued that economic development and democracy create new opportunities and resources for women to access political power, which should increase gender equality in politics. However, empirical evidence from previous research that supports this argument is mixed. The contribution of this study is to expand the research on gender equality in politics through an in-depth examination of the effect of development and democracy on gender equality in cabinets. This has been completed through separate analyses that include most of the countries in the world across three levels of development (least-developed, developing, and developed) and across different types of political regimes (democracies, royal dictatorships, military dictatorships, and civilian dictatorships). The results demonstrate that economic development and democracy only affect gender equality in cabinets positively in a few environments. Accordingly, the context is important and there seem to be thresholds before development and democracy have any effect. Development has a positive effect in developed countries and in democracies, but it has a negative effect in dictatorships, and the negative effect is strongest in military dictatorships. The level of democracy has a positive effect mainly in dictatorships, and the strongest effect is in civilian dictatorships. The article demonstrates the importance of dividing samples into subsets to increase understanding of what affects women's representation in cabinets in different environments, and I ask scholars to subset samples and run separate analyses more often in comparative studies.

scholarly journals EXTRAPLEURAL PNEUMOLYSIS FOR CAVITARY PULMONARY TUBERCULOSIS TREATMENT

2020 ◽  
pp. 15-20
Author(s):  
P. G. Gadzhieva ◽  
D. B. Giller ◽  
A. A. Glotov ◽  
O. Sh. Kesaev ◽  
V. V. Koroev ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Multidrug Resistant ◽  
Pathological Process ◽  
Tuberculosis Treatment ◽  
Long Term Results ◽  
Filling Material ◽  
Different Types ◽  
Positive Effect ◽  
Observation Period

Objective. To increase efficiency of cavitary pulmonary tuberculosis treatment by developing modern indications and technology of extrapleural pneumolysis with filling material.Material and methods. We reviewed 25 patients with cavitary pulmonary tuberculosis and bacterial excretion who had undergone extrapleural pneumolysis with different types of filling material in 2004–2015. In 16 cases, we performed surgery in patients with one lung.Results. 56% of operated patients demonstrated extensively drug-resistant TB, 40% had multidrug-resistant TB. Cavities were closed and bacterial excretion ceased in 92% of patients at discharge. Long-term results with observation period from 1 to 12 years were analyzed in 24 patients, 17 (71%) of them had complete clinical efficacy.Conclusion. Extrapleural pneumolysis is a mini-invasive surgical treatment that can prove positive effect in patients with non-fibrotic changes in a cavity wall and pathological process in upper parts of the lungs. 

scholarly journals An Experimental Study on a Composite Bonding Structure for Steel Bridge Deck Pavements

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiaoguang Zheng ◽  
Qi Ren ◽  
Huan Xiong ◽  
Xiaoming Song
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Epoxy Resin ◽  
Bonding Strength ◽  
Bridge Deck ◽  
Steel Bridge ◽  
Shear Tests ◽  
Bonding Structure ◽  
Asphalt Overlay ◽  
Strength Tests

As one of the major contributors to the early failures of steel bridge deck pavements, the bonding between steel and asphalt overlay has long been a troublesome issue. In this paper, a novel composite bonding structure was introduced consisting of epoxy resin micaceous iron oxide (EMIO) primer, solvent-free epoxy resin waterproof layer, and ethylene-vinyl acetate (EVA) hot melt pellets. A series of strength tests were performed to study its mechanical properties, including pull-off strength tests, dumbbell tensile tests, lap shear tests, direct tension tests, and 45°-inclined shear tests. The results suggested that the bonding structure exhibited fair bonding strength, tensile strength, and shear strength. Anisotropic behaviour was also observed at high temperatures. For epoxy resin waterproof layer, the loss of bonding strength, tensile strength, and shear strength at 60°C was 70%, 35%, and 39%, respectively. Subsequent pavement performance-oriented tests included five-point bending tests and accelerated wheel tracking tests. The impacts of bonding on fatigue resistance and rutting propagation were studied. It was found that the proposed bonding structure could provide a durable and well-bonded interface and was thus beneficial to prolong the fatigue lives of asphalt overlay. The choice of bonding materials was found irrelevant to the ultimate rutting depth of pavements. But the bonding combination of epoxy resin waterproof and EVA pellets could delay the early-stage rutting propagation.

scholarly journals Strength Tests and Numerical Simulations of Loess Modified by Desulfurization Ash and Fly Ash

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 512
Author(s):  
Zhi Cheng ◽  
Xinrong Cheng ◽  
Yuchao Xie ◽  
Zhe Ma ◽  
Yuhao Liu
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Power Plants ◽  
Utilization Rate ◽  
Direct Shear ◽  
Test Results ◽  
Mass Ratio ◽  
Direct Shear Tests ◽  
Strength Tests ◽  
Actual Test

Desulfurization ash and fly ash are solid wastes discharged from boilers of power plants. Their utilization rate is low, especially desulfurization ash, most of which is stored. In order to realize their resource utilization, they are used to modify loess in this paper. Nine group compaction tests and 32 group direct shear tests are done in order to explore the influence law of desulfurization ash and fly ash on the strength of the loess. Meanwhile, FLAC3D software is used to numerically simulate the direct shear test, and the simulation results and the test results are compared and analyzed. The results show that, with the increase of desulfurization ash’s amount, the shear strength of the modified loess increases first and then decreases. The loess modified by the fly ash has the same law with that of the desulfurization ash. The best mass ratio of modified loess is 80:20. When the mass ratio is 80:20, the shear strength of loess modified by the desulfurization ash is 12.74% higher than that of the pure loess on average and the shear strength of loess modified by fly ash is 3.59% higher than that of the pure loess on average. The effect of the desulfurization ash on modifying the loess is better than that of the fly ash. When the mass ratio is 80:20, the shear strength of loess modified by the desulfurization ash is 9.15% higher than that of the fly ash on average. Comparing the results of the simulation calculation with the actual test results, the increase rate of the shear stress of the FLAC3D simulation is larger than that of the actual test, and the simulated shear strength is about 8.21% higher than the test shear strength.

Water resistance of heat-treated welded Iroko, ash, tulip, and ayous wood

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9584-9595
Author(s):  
Mustafa Zor
Keyword(s):  
Shear Strength ◽  
Water Resistance ◽  
Chemical Constituents ◽  
Water Immersion ◽  
Control Sample ◽  
Strength Loss ◽  
Control Group ◽  
Line Density ◽  
Heat Treated ◽  
Structural Applications

The friction welding method has been an effective criterion in determining the mechanical performance of wood joints in wood industry applications compared to traditional methods. Although it is used in structural applications, joints from linear vibration are quite sensitive to water. In this study, the water resistance of the heat-treated woods, iroko (Chlorophora excelsa), ash (Fraxinus excelsior L.), tulip wood (Liriodendron tulipifera) and ayous (Triplochiton scleroxylon), were investigated by friction linear welding. The weld line density profiles were examined. The resistance of heat-treated welded wood joints to water remarkably decreased compared to the control sample, depending on water immersion time. The highest shear strength loss was found in tulip wood (60% to 65%) and the lowest shear strength loss was found in ash wood (3%) for the heat-treated group and in Iroko wood (17%) for the control. The heat-treated samples increased in density with welding but had a slightly lower density than the control group. According to the TGA results, it was found that the thermal degradation of untreated welded woods was lower than that of heat-treated welded woods. This difference could be due to the chemical constituents of hardwood and tropical wood. X-ray computed tomography (CT-scanning) is feasible and usable for welding line density change.

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