scholarly journals Optimization of Chitosan Properties with the Aim of a Water Resistant Adhesive Development

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 4031
Author(s):  
Jeanne Silvestre ◽  
Cédric Delattre ◽  
Philippe Michaud ◽  
Hélène de Baynast
Keyword(s):  
Wastewater Treatment ◽  
Water Resistance ◽  
Food Supplements ◽  
Water Soluble ◽  
Background Information

Chitosan is a bio-sourced polysaccharide widely used in different fields from health to wastewater treatment through food supplements. Another important use of this polymer is adhesion. Indeed, the current demand to replace non-natural and hazardous polymers by greener ones is well present in the adhesive field and open good opportunities for chitosan and its derivatives. However, chitosan is water soluble and exhibits a poor water-resistance in the field of adhesion which reduces the possibilities of its utilization within the paste field. This review focuses on exploration of different ways available to modify the chitosan and transform it into a water-resistant adhesive. The first part concerns the chitosan itself and gives important information from the discovery of chitin to the pure chitosan ready to use. The second part reviews the background information relative to adhesion theories, ideal properties of adhesives and the characteristics of chitosan as an adhesive. The last part focuses on exploration of the possible modification of chitosan to make it a water-resistant chemical adhesive.

scholarly journals Semi-Crystalline Hydrophobic Polyamidoamines: A New Family of Technological Materials?

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1018
Author(s):  
Massimo Marcioni ◽  
Jenny Alongi ◽  
Elisabetta Ranucci ◽  
Mario Malinconico ◽  
Paola Laurienzo ◽  
...  
Keyword(s):  
Maximum Stress ◽  
Water Resistance ◽  
Prolonged Exposure ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Molecular Weights ◽  
New Family ◽  
Methylene Groups ◽  
Methane Flame

The hitherto known polyamidoamines (PAAs) are not suitable as structural materials because they are usually water-soluble or swellable in water. This paper deals with the synthesis and characterization of semi-crystalline hydrophobic PAAs (H-PAAs) by combining different bis-sec-amines with bis-acrylamides obtained from C6–C12 bis-prim-amines. H-PAAs were initially obtained in a solution of benzyl alcohol, a solvent suitable for both monomers and polymers. Their number average molecular weights, M¯n, which were determined with 1H-NMR by evaluating the percentage of their terminal units, varied from 6000 to >10,000. The solubility, thermal properties, ignitability and water resistance of H-PAAs were determined. They were soluble in organic solvents, semi-crystalline and thermally stable. The most promising ones were also prepared using a bulk process, which has never been previously reported for PAA synthesis. In the form of films, these H-PAAs were apparently unaffected by water. The films underwent tensile and wettability tests. They showed similar Young moduli (260–263 MPa), whereas the maximum stress and the stress at break depended on the number of methylene groups of the starting bis-acrylamides. Their wettability was somewhat higher than that of common Nylons. Interestingly, none of the H-PAAs considered, either as films or powders, ignited after prolonged exposure to a methane flame.

scholarly journals PEAT-CONTAINING COMPOSITION CONTAINING MAGNESIA BINDER

2018 ◽  
Vol 61 (8) ◽  
pp. 81
Author(s):  
Natalia A. Mitina ◽  
Vasiliy A. Lotov ◽  
Margarita A. Kovaleva ◽  
Natali O. Kopanitsa
Keyword(s):  
Water Resistance ◽  
Vertical Direction ◽  
Water Soluble ◽  
Fluid Mixing ◽  
Thin Plates ◽  
Hydration Reaction ◽  
Strength Parameters ◽  
Hydrogen Carbonates ◽  
Hardening Coefficient ◽  
Caustic Magnesia

Based on the new hydraulic magnesia binder, the compositions of the peat-containing composite material have been proposed and investigated. Hydraulic magnesia binder is an astringent composition of hydration-reaction hardening, which consists of an active caustic magnesia powder and a mixing fluid. As the fluid mixing an aqueous solution of magnesium bicarbonate Mg(HCO3)2 with a concentration of 13 g/l was used. Hardening forms water-insoluble products - magnesium hydroxide Mg(OH)2 and magnesium bicarbonates of general formula MgCO3·zMg(OH)2·nH2O, which makes it possible to harden and used products based on such a binder as in the air, and in water. The use of peat as a filler of the developed compositions will make it possible to obtain lightweight waterproof materials and products of heat-insulating purpose. It has been shown that the peat-and-magnesian compositions of all compositions have a hydration hardening coefficient of more than 1.0, which indicates intensification of the hydration and hardening processes in water conditions in comparison with air and large strength parameters. Using XRD the phase composition of peat products and peat- magnesium hardening compositions was established. Thermal analysis showed the presence of magnesium hydrogencarbonates in samples of compositions that are in the form of slightly crystallized neoplasms. Investigations by electron microscopy confirmed the presence of hydrocarbons such as magnesium particles dipingite Mg5(CO3)4(OH)2·5H2O and hydromagnesite Mg5(CO3)4(OH)2·4H2O in the form of thin plates with the vertical direction of crystallization. Increased water resistance of compositions based on hydraulic magnesia binder with non-water-resistant filler peat is due to mineralization of peat particles due to their impregnation with a solution of magnesium bicarbonate and the formation of water-soluble magnesium hydrogen carbonates in the loose porous structure of peat.

A new soybean meal-based bioadhesive enhanced with 5,5-dimethyl hydantoin polyepoxide for the improved water resistance of plywood

RSC Advances ◽  
2015 ◽  
Vol 5 (77) ◽  
pp. 62957-62965 ◽  
Author(s):  
Jing Luo ◽  
Chenchen Li ◽  
Xiaona Li ◽  
Jianlin Luo ◽  
Qiang Gao ◽  
...  
Keyword(s):  
Soybean Meal ◽  
Water Resistance ◽  
Water Soluble

The primary goal of this study is to improve the water resistance of a soybean meal-based bioadhesive and its resultant plywood with water-soluble 5,5-dimethyl hydantoin polyepoxide (DMHP).

Water Resistance of Neoprene

1938 ◽  
Vol 11 (2) ◽  
pp. 383-393
Author(s):  
Howard W. Starkweather ◽  
Herbert W. Walker
Keyword(s):  
Zinc Oxide ◽  
Natural Rubber ◽  
Water Absorption ◽  
Chemical Reaction ◽  
Water Resistance ◽  
Water Soluble ◽  
Significant Change

Abstract Superior water resistance of well-cured Neoprene, like that of natural rubber, depends upon the absence of water-soluble ingredients and agents that are capable of absorbing water. It has been shown that the water resistance of Neoprene varies greatly with different activating agents. This paper includes a more detailed study of the water absorption of Neoprene—magnesia—zinc oxide compounds and describes certain loaded stocks with improved water resistance. The water absorption was determined by the method already outlined, using slabs 0.20 cm. thick. Calculation of Water Absorption The water absorption can be calculated from the increase in weight or from the increase in volume of a stock during immersion in water. A difference between these values is an indication of chemically combined water. This is based upon the assumption that water undergoes no significant change in volume during absorption but that there is a change in volume during a chemical reaction. The two methods of calculating the absorption of water are shown by the equations:

Preparation of UV Curable Waterborne Polyurethane and its Application in Coatings

2013 ◽  
Vol 821-822 ◽  
pp. 925-928
Author(s):  
Lei Wang ◽  
Xiao Juan Lai ◽  
Shao Yun Ma
Keyword(s):  
Electron Microscopy ◽  
Water Resistance ◽  
Waterborne Polyurethane ◽  
Water Soluble ◽  
Cross Linking ◽  
Crosslinking Degree ◽  
Uv Curable ◽  
Transmission Electron ◽  
Solidification Reaction ◽  
Test Result

Waterborne UV curable polyurethane emulision containing C=C bond was prepared with self-emulsification. 3% water soluble photoinitiator was added to the polyurethane emulision, and polyurethane films was prepared by ultraviolet irradiation. The structure of the polyurethane emulision and films were confirmed by means of Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and thermogravimetric analysis. FTIR test result shows that cross linking and solidification reaction of C=C double bond happened after UV irradiation. When C=C content increases, the particle size of polyurethane emulision increases, crosslinking degree of films increases, water resistance and heat resistance have both been improved. When C=C content is 8.51%, gel content is more than 90% and the lowest water absorption can be 12.5%.

scholarly journals Effect of Dip Coating Polymer Solutions on Properties of Thermoplastic Cassava Starch

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1746
Author(s):  
Kittisak Jantanasakulwong ◽  
Nattagarn Homsaard ◽  
Phanurot Phengchan ◽  
Pornchai Rachtanapun ◽  
Noppol Leksawasdi ◽  
...  
Keyword(s):  
Water Resistance ◽  
Thermoplastic Starch ◽  
Dip Coating ◽  
Cassava Starch ◽  
Water Soluble ◽  
Poly Lactic Acid ◽  
Solution Technique ◽  
Coating Process ◽  
Melt Mixing ◽  
Coating Solution

Thermoplastic starch (TPS) was prepared by melt-mixing cassava starch with glycerol. Polyethylene (PE), polyethylene-grafted-maleic anhydride (PE-MAH) and poly(lactic acid) (PLA) solutions at 2% (w/v) were used to coat TPS using the dip coating process. The tensile strength of TPS increased with the dip coating solution technique, especially for PLA coating. Swelling index, water-soluble matter and water droplet contact angle confirmed the water resistant improvement of TPS by PE-MAH and the PLA dip coating solution. Plasticizer bleeding was found in uncoated TPS after storage, but not in the coated TPS. Coating TPS with PE-MAH and PLA improved the tensile properties, water resistance and conquered plasticizer bleeding problems in TPS.

scholarly journals Galvanic Wastewater Treatment by Means of Anionic Polymer Enhanced Ultrafiltration

2012 ◽  
Vol 19 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Irena Korus
Keyword(s):  
Wastewater Treatment ◽  
Metal Binding ◽  
Metal Ion ◽  
Water Soluble ◽  
Partial Recovery ◽  
Solution Ph ◽  
Anionic Polymer ◽  
Metal Retention ◽  
Metal Separation ◽  
Polymer Metal

Galvanic Wastewater Treatment by Means of Anionic Polymer Enhanced Ultrafiltration This work is focused on polyelectrolyte enhanced ultrafiltration as an effective heavy metal separation technique. Three types of effluents, containing Zn(II), Cu(II) and Ni(II) ions, were subjected to the separation process. Poly(sodium 4-styrenesulfonate) - PSSS, a water soluble anionic polyelectrolyte was used as a metal binding agent. Two Sepa® CF (Osmonics) membranes: EW, made of polysulfone and a modified polyacrylonitrile membrane MW, were used in the ultrafiltration process. The preliminary UF tests were carried out on model solutions with target metal ion concentrations of 10, 100 and 250 mg dm-3. The main parameters affecting the metal retention (the polyelectrolyte quantity and solution pH) were examined. The values of pH 6 and polymer : metal concentration ratio CPSSS : CM = 7.5 : 1 (mol of mer unit per mol of metal) were selected to perform the galvanic wastewater ultrafiltration-concentration tests. Three types of wastewater containing Zn(II), Ni(II) and Cu(II) ions within the concentration range of 30÷70 mg dm-3 were used in the investigations. Very high metal retention coefficients, up to > 99%, were achieved. The retentates obtained were subjected to the decomplexation-ultrafiltration (pH = 1) and subsequent diafiltration step, which enabled partial recovery of concentrated metal ions and the polyelectrolyte. The recovered polyelectrolyte was reused toward Ni(II) ions and the high effectiveness of metal separation has been achieved.

Log DOW: Key to Understanding and Regulating Wastewater-Derived Contaminants

2006 ◽  
Vol 3 (6) ◽  
pp. 439 ◽  
Author(s):  
Martha J. M. Wells
Keyword(s):  
Drinking Water ◽  
Wastewater Treatment ◽  
Water Treatment ◽  
Surface Water ◽  
Water Distribution ◽  
Drinking Water Treatment ◽  
The United States ◽  
Water Soluble ◽  
Water And Wastewater Treatment ◽  
Ph Dependent

Environmental Context. Worldwide, surface water is a source of drinking water and is a recipient of wastewater effluents and pollutants. Many surface water bodies undergo a natural, cyclical, diurnal variation in pH between 7 and 9. Most drinking water and wastewater treatment in the United States is conducted between pH 7 and 8. The pH of water undergoing treatment processes directly impacts the ratio of nonionized to ionized chemical form(s) present, which in turn impacts the success rate of contaminant removal. Many organic wastewater-derived contaminants are very water soluble at pH 7–8 and are inadequately treated. Abstract. Wastewater-derived contaminants (WWDCs) occur in surface water due to inadequate wastewater treatment and subsequently challenge the capabilities of drinking water treatment. Fundamental chemical properties must be understood to reduce the occurrence of known WWDCs and to better anticipate future chemical contaminants of concern to water supplies. To date, examination of the fundamental properties of WWDCs in surface water appears to be completely lacking or inappropriately applied. In this research, the hydrophobicity–ionogenicity profiles of WWDCs reported to occur in surface water were investigated, concentrating primarily on pharmaceuticals and personal care products (PPCPs), steroids, and hormones. Because most water treatment is conducted between pH 7 and 8 and because DOW, the pH-dependent n-octanol–water distribution ratio embodies simultaneously the concepts of hydrophobicity and ionogenicity, DOW at pH 7–8 is presented as an appropriate physicochemical parameter for understanding and regulating water treatment. Although the pH-dependent chemical character of hydrophobicity is not new science, this concept is insufficiently appreciated by scientists, engineers, and practitioners currently engaged in chemical assessment. The extremely hydrophilic character of many WWDCs at pH 7–8, indicated by DOW (the combination of KOW and pKa) not by KOW of the neutral chemical, is proposed as an indicator of occurrence in surface water.

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