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.

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.

Effect of Water-Soluble Carbon Nanotubes on the Mechanical Properties and early Hydration of Alkali-Activated Slag

2014 ◽  
Vol 1000 ◽  
pp. 118-121 ◽  
Author(s):  
Pavel Rovnaník ◽  
Patrik Bayer
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Cementitious Materials ◽  
Water Soluble ◽  
Strength Parameters ◽  
Early Hydration ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Hydration Characteristics ◽  
Alkali Activated

Alkali-activated slag (AAS) is a material which has great potential for use in building industry. The aim of this work was to gain new superior properties by the addition of carbon nanotubes (CNTs). This material can act as a microreinforcement improving mechanical properties of cementitious materials. The effect of 0–1 wt.% addition of CNTs on the mechanical properties, hydration characteristics and microstructure of AAS binder was determined. The addition of CNTs delays the setting of the binder and a partial deterioration of strength parameters was observed.

The Influence of Chemical Additives on Strength of Wood-Cement Composite

2019 ◽  
Vol 972 ◽  
pp. 69-76
Author(s):  
Vyacheslav Zaprudnov ◽  
Victor Sanaev ◽  
Sergei Karpachev ◽  
Dmitry Levushkin ◽  
Galina Gorbacheva
Keyword(s):  
Liquid Glass ◽  
Aluminum Sulfate ◽  
Cement Composite ◽  
Water Soluble ◽  
Optimal Consumption ◽  
Chemical Additives ◽  
Strength Parameters ◽  
Green Wood ◽  
Complex Chemical ◽  
Harmful Effects

The strength and strains of the wood-cement composite primarily depend on the main technоlogical factors such as the used type of binder and wood filler, the method of wood filler preparation, the method of molding, the conditions of hardening. The aim of this work is an experimental study of the chemical additives influence on wood filler to localize the harmful effects of water-soluble wood substances on the processes of hydration and hardening of cement. Using the additives, it is possible to achieve satisfactory strength parameters even on green wood. The maximum strength was obtained when complex chemical additives were applied. The most effective additives involved calcium chloride, liquid glass, aluminum sulfate, lime and ethanolamines. The optimal consumption and ratio of the complex additives components costs also depend on the degree of preliminary wood exposure.

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 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.

Modification of hemicelluloses with polycarboxylic acids

Holzforschung ◽  
2013 ◽  
Vol 67 (5) ◽  
pp. 567-571 ◽  
Author(s):  
Juris Zoldners ◽  
Tatiana Kiseleva
Keyword(s):  
Potassium Hydroxide ◽  
Water Resistance ◽  
Water Vapor Sorption ◽  
Water Soluble ◽  
Sodium Hypophosphite ◽  
Crosslinking Reaction ◽  
Vapor Sorption ◽  
Natural Polymers ◽  
Polycarboxylic Acids ◽  
Crosslinking Agents

Abstract Polycarboxylic acids (PCAs) aroused interest as crosslinking agents for natural polymers, such as cellulose, starch, chitosan, and hemicelluloses (HC), for improving their water resistance and imparting them new properties. Here, PCAs were studied for the crosslinking of HC films. HCs were isolated from gray alder (Alnus incana L.) wood as a water-soluble fraction by sawdust extraction with 7% potassium hydroxide. Citric acid (CA), maleic acid (MA), and butane tetracarboxylic acid (BTCA) served as crosslinking agents in the presence of sodium hypophosphite as a catalyst. The crosslinking reaction was followed by the analysis of free and esterified COOH groups in HC films. At temperatures below 100–110°C, the HC esterification process with BTCA proceeded very slowly. At 140°C, most of the acids’ COOH groups reacted with HC during 1–1.5 h. BTCA had a higher esterification activity than CA and MA. The obtained films retained their form on immersing in water and subsequent drying in the open air. The water retention value of films followed the reaction kinetics, that is, decreased with increasing reaction time. Water-resistant films were obtained with no <10–11% of BTCA and 20% of CA based on the weight of HC. The water vapor sorption capacity of the films after modification with 10% BTCA decreased approximately twice in the whole range of the relative humidity of air compared with the case of unmodified HC films.

Influence of Carbon Nanomodifier on the Structure and Properties of the Modified Gypsum Binder

2020 ◽  
Vol 992 ◽  
pp. 233-237
Author(s):  
Larisa Yu. Matveeva ◽  
D.G. Letenko ◽  
M.V. Mokrova
Keyword(s):  
Water Resistance ◽  
Bending Strength ◽  
Single Layer ◽  
Joint Effect ◽  
Water Soluble ◽  
Strength Characteristics ◽  
Structure And Properties ◽  
Water Soluble Polymer ◽  
Weather Resistance ◽  
Mixing Water

Water-soluble polymer and latex additives are used to give the gypsum building plaster elasticity and placeability, improved water resistance and increased bending strength. The nanomodifiers in the form of carbon single-layer and multi-layer nanotubes, fullerenes and other nanoparticles are used for the formation of the structure of a gypsum stone with improved strength characteristics and improved weather resistance. In this work, the joint effect of the plasticizer based on polycarboxylate and the carbon nanomodifier on the structure, physicomechanical properties, and water resistance of the gypsum stone is investigated. It is shown that nanomodifiers contribute to the increase in the plasticizing ability of carboxylate additives, which leads to the significant decrease in the amount of mixing water, and as a result, to the increase in density, decrease in the porosity of the gypsum stone and the increase in its strength characteristics and water resistance.

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