Dimethylol Urea Research Articles

Crosslinking Mechanism of Tannin-Based Adhesives Based on Model Compounds: Copolycondensation of Resorcinol with Dimethylol Urea

This study focuses on the competition reaction rules of a system containing resorcinol (as a tannin model compound) and dimethylol urea (as a urea–formaldehyde resin model compound) under various alkaline and acidic environments. The aim is to investigate the crosslinked modification mechanism of urea–formaldehyde resin with tannin adhesive. The study delves into the competitive relationship between self-condensation polymerization reactions and co-condensation polymerization reactions. It specifically highlights the conditions for the copolycondensation reaction of dimethylolurea and resorcinol and validates its rationality through an examination of the resorcinol–urea–formaldehyde system’s reaction rules. The results show that (1) under strongly acidic conditions, the activity of carbocation intermediates produced by hydroxymethyl resorcinol for the resorcinol phenol ring is higher than the electrophilic reactivity of nitrogen atoms on hydroxymethyl urea, which is more beneficial for the resorcinol–formaldehyde self-polycondensation reaction, and the co-polycondensation structures do not play a dominant role. (2) Under weakly acidic conditions, the co-polycondensation structures are evidently advantageous over self-polycondensation structures, and the degree of the co-polycondensation reaction is positively correlated with pH below the neutral point of resorcinol. (3) Under alkaline conditions, the self-polycondensation between resorcinol and formaldehyde is dominant in the system. (4) The concentration of hydroxymethyl urea carbocation is the key factor to determine the degree of the co-polycondensation reaction.

SYNTHESIS OF A DOUBLE COMPOUND BASED ON DIMETHYLOL UREA AND PHYTOCOMPOUND OF MOLYBDENUM AND THE STUDY OF ITS INFLUENCE ON THE POPULATION OF SOME SOIL MICROORGANISMS AND ACCUMULATION OF NITROGEN

Drillers used for agricultural crops, in particular cotton seeds, cannot provide additional nitrogen feeding in the required volume during a shortage of nitrogen fertilizers. This article sets the task of creating a new active substance based on the phyto compound dimethylolure and molybdenum, which allows you to reduce cotton diseases in cotton cultivation, increase the accumulation of light hydrolyzed nitrogen in the soil and obtain a high cotton yield. The purpose. Study of chemical interactions in a three-component aqueous-salt system of dimethylolure-molybdenum phyto-compound-water by isothermal method. Objects. DMM, FSMo, double compound DMM is the active reactant of FSMo. Results.The isothermal method at a temperature of 25°C found that in the concentration range of solutions of 12.2-9.8% DMM and 2.8-5.4% FSMo, DMM crystallizes in the system, at a concentration range of 5.7-2.1% DMM and 12.3-15.5% FSMo, FSMo crystallizes, and in the concentration range of 8.2 -6.4% DMM and 6.2-9.3% FSMo, the compound DMM•FSMo is separated from the solution into this phase.Conclusion. The chemical interaction in the water-salt system dimethylol urea (DMM) - molybdenum phytocompound (FSMo) - water was studied by isothermal methods of chemical analysis. The region of crystallization of a new double compound, an active substance based on DMM and FSMo, was established at a molar ratio of 4DMM•FSMo. On model soil samples, it was determined that the active substance - the double compound 4DMM•FSMo against the background of ammonium nitrate, in comparison with ammonium nitrate, increases the number of nitrogen-fixing bacteria by 3.0 and 3.2 times.

Design Principles to Maximize Non‐Bonding States for Highly Tribopositive Behavior

AbstractThe development of highly tribopositive materials is crucial for realizing high‐performance triboelectric nanogenerators. In this study, a novel protocol to maximize the number of non‐bonding electrons with local dipoles for designing highly tribopositive materials is introduced, and nitrogen‐based dimethylol urea, diazolidinyl urea, and imidazolidinyl urea as promising tribopositive materials are suggested. The mechanism by which nitrogen‐based materials provide highly tribopositive properties is investigated using calculations based on density functional theory. Highly electronegative atoms, such as nitrogen and oxygen, attract electrons from neighboring atoms, resulting in the formation of negative local dipoles in the highest occupied molecular orbital band composed of non‐bonding electrons, thereby creating an electron‐donating environment. The proposed design protocol is confirmed by quantitatively investigating the triboelectric properties of nitrogen‐based materials, and analyzing the charge transfer characteristics of dimethylol urea based on dipole interactions.

Design of Highly Positive Triboelectric Materials Via Controlling Local Dipole

The design of positive triboelectric materials is highly required to realize high-performance triboelectric generators. Here, we establish a novel design protocol for highly positive triboelectric materials via the maximization of local dipole and suggest nitrogen-based dimethylol urea, diazolidinyl urea, and imidazolidinyl urea as promising positive triboelectric materials. The mechanism that nitrogen-based materials provide highly positive triboelectric properties is investigated using density functional theory calculation. Highly electronegative atoms (e.g. nitrogen and oxygen) attract electrons from neighboring atoms, resulting in the formation of negative local dipoles in the highest occupied molecular orbital consisting of non-bonding electrons, thereby forming an electron-donating environment. We confirmed the proposed design protocol by quantitatively investigating the triboelectric properties of nitrogen-based materials and analyzing the charge transfer characteristics based on local dipole interactions.

Development of a novel and benign emulsion paint binder from epoxidized soybean oil and dimethylol urea blend

To develop a novel emulsion paint binder, dimethylol urea (DMU) resin synthesized from low formaldehyde to urea stoichiometric ratio (2:1) was blended with epoxidized soybean oil (ESBO) with 2.56 % oxirane oxygen and 67 % iodine value conversion. ESBO/DMU blends were prepared by varying the amount of ESBO from 10 – 70 %. The blends were analyzed for formaldehyde emission, viscosity, refractive index, turbidity, density, gelation time and solubility in water, while the blends’ films were analyzed for moisture uptake and melting point. Homogenous blends were obtained up to 50% ESBO/DMU blend, while FTIR analyses show reactive ESBO/DMU blend at optimum blending. Formaldehyde emission and moisture uptake were reduced in the blends’ film, while ESBO also act as plasticizer by introducing softness in the blends’ film. Comparison of the properties of 40% ESBO/DMU optimum blend with other reported binders shows its good potentials and its capability to compete in the coating industry.

Dimethylolurea as a Novel Slow-Release Nitrogen Source for Nitrogen Leaching Mitigation and Crop Production.

Rapid hydrolysis of urea results in further fertilization frequency and excessive nitrogen (N) input. A modified urea, dimethylolurea (DMU), was synthesized in this study. The structure of the sample was characterized by Fourier transform infrared and nuclear magnetic resonance analysis, manifesting the formation of DMU. N release investigation confirmed that DMU enabling provided a gradual N supply. The N leaching experiment indicated that increasing the applied DMU significantly reduced the NH4+-N, NO3--N, and total N leaching, compared with urea application alone. The application effect on maize and wheat was evaluated. The results revealed that singly applied DMU with 100% or 80% N input, irrespective of the amount, promoted crop yield and agronomic characteristic and N use efficiency (NUE) of maize and wheat, beyond urea with two split applications at the recommended rate. Thus, the potential availability of DMU was proven; this could be widely used in agricultural fields as a slow-release fertilizer.

Pengaruh Jenis Substitusi Bahan Ikat Silang dan Komposisi Perekat terhadap Penurunan Emisi Formaldehida pada Papan Serat

This study aims to determine the effect of the substitution type of cross lingking agent and adhesive composition of the against formaldehyde emission on fiberboard. The cross lingking agent substitution of fiberboard that made in this study are hexamethylene tetramine, ethylene glycol , dimethylol urea with the composition of melamine formaldehyde: 80%, 70%, 60%, 50%, 40%, and 0%. The best cross lingking agent material and meet with standard of JIS A 5905 in lowering formaldehyde emission is ethyenel glycol in the adhesive composition IV

Analisa Sifat Fisikokimia Tanin Kulit Akasia Mangium Untuk Bahan Baku Perekat

Tannin is a derivative from organic compound from glycosides found in various plants, the mos t important commercial condensed t annin oblained from gymnosperms species for example Acacia mangium. Tannin is one of the adhesive materials that can have a dimension al stability of wood. Tannin contains flavonoid compounds that have hydroxyl groups that are reactive to condense against other materials as a cross-link agent, like formaldehyde, which may increase the number of polymer units of tannins, thus increasing the bonding strength of tannin based adhesives. Based on the results of physicochemical analysis of extracts (tannins) from the bark of A. mangium as a raw material for adhesives, it can be conc l u d e d that the A. mangium tannin had a higher reactivity toward formaldehyde of 96%, reactivity of t annin toward h examefhylene tetramine of 46.18%, tannins toward ethylene glycol of 3.07% and tannins toward dimeth yl ol urea of 183.59%. Meanwhile, the value of reactive polyphenol content determined by UV-Method showed in tannin with formaldehyde of 97.65%, tannins with hexamethylene tetramine of 46%, tannins with ethylene glycol of 2%, and tannins with dimelhylolurea of 56.26%. The resuits of gelation time (gel t ime) measurements ful l filled the requirements of JIS K 6833- 1980 by the treatment of hexamelhylenen t etramine for variable II and III, and the treatment of ethylene glycol (variable VI). The viscosity values by t he Ireatment of hexamethylenen tetramine (variable II, III, and IV), for ethylene glycol (variable II - VI) met the requirement conditions by JIS K 6833-1980.

Separation of urea, hexamethylenetetramine, and their reaction products in sol–gel feed solution by zwitterionic HILIC

ABSTRACTStudies were carried out to develop a chromatographic methodology based on hydrophilic interaction liquid chromatography (HILIC) for the separation of various reaction products of hexamethylenetetramine (HMTA) –urea used in the sol–gel process for the preparation of ceramic microspheres. Different chromatographic parameters such as organic modifiers, pH of mobile phase, buffer concentration, column temperature, etc. were studied to arrive at the optimum conditions for separation. Compounds such as urea, monomethylolurea (MMU), dimethylolurea (DMU), and HMTA were separated from a synthetic mixture using a mobile phase consisting of acetonitrile and acetate buffer of pH 6. The methodology developed based on HILIC stationary phase is simple and amicable for integration with electrospray ionization mass spectrometry (ESI-MS) to identify the unknown reaction products. The methodology was applied for the separation of reaction products in pre-boiled and untreated urea–HMTA mixtures used as feed in the sol–gel process.

Application of Sericin on Polyester Fabric

Sericin is a natural protein which is removed from silk in a process called degumming. In India, 250-300 tons of sericin is extracted per year and goes as waste, it has wide range of application because of its properties like antioxidant, antibacterial, UV resistant, anticoagulant and moisture retention capacity. This paper is concerned with the application of sericin on polyester fabrics using cross linking agents like di-methylol di-hydroxy ethylene urea (DMDHEU) and glutaraldehyde. The Polyester fabrics are pretreated with sodium hydroxide (NaOH) and low temperature plasma (Oxygen gas). This pretreated sericin applied polyester fabrics show the better improvement in the wicking (moistureabsorbency) and good dye uptake properties on acid dyed fabric and it will be used for medical application.

Interaction between dimethylol urea and sodium chloride in water

Theoretical bases for chemical melioration of dimethylol urea (DMU) in soils having chloride salinity were studied. The solubility in the DMU-sodium chloride-water system was studied using visual-polythermal and isothermal analysis. Experiments were carried out to elucidate the effect of dimethylol urea on the germinability and germinative power of cotton plant seeds.

Quantitative and qualitative 1H, 13C, and 15N NMR spectroscopic investigation of the urea–formaldehyde resin synthesis

Urea-formaldehyde resins are bulk products of the chemical industry. Their synthesis involves a complex reaction network. The present work contributes to its elucidation by presenting results from detailed NMR spectroscopic studies with different methods. Besides (1)H NMR and (13)C NMR, (15)N NMR spectroscopy is also applied. (15)N-enriched urea was used for the investigations. A detailed NMR signal assignment and a model of the reaction network of the hydroxymethylation step of the synthesis are presented. Because of its higher spectral dispersion and the fact that all key reactions directly involve the nitrogen centers, (15)N NMR provides a much larger amount of detail than do (1)H and (13)C NMR spectroscopy. Symmetric and asymmetric dimethylol urea can be clearly distinguished and separated from monomethylol urea, trimethylol urea, and methylene-bridged urea. The existence of hemiformals of methylol urea is confirmed. 1,3,5-Oxadiazinan-4-on (uron) and its derivatives were not found in the reaction mixtures investigated here but were prepared via alternative routes. The molar ratios of formaldehyde to urea were 1, 2, and 4, the pH values 7.5 and 8.5, and the reaction temperature 60 °C.

Synthesis, Characterization and Glass Reinforcement of Dimethylolurea-3-AminoPhenol-Epoxy Resin Curing Systems

N,N′-Dimethylolurea (DMU) was prepared and condensed with 3-aminophenol (AP) in the presence of alcoholic alkali catalyst at varying mole ratios of DMU: AP. The resultant dimethylolurea-3-aminophenol (DMUAP) resins were characterized. DMUAP-epoxy curing systems have been prepared by mixing DMUAP and epoxy resin (DGEBA) in different proportions. The curing study of DMUAP-epoxy systems was monitored on DSC and kinetic parameters were evaluated. Based on DSC data, glass-reinforced composites of DMUAP-epoxy systems have been laminated and characterized. The unreinforced cured material of DMUAP-epoxy systems were analyzed by thermogravimetric analysis (TGA).

Utilization of Wheat Straw for the Preparation of Coated Controlled-Release Fertilizer with the Function of Water Retention

With the aim of improving fertilizer use efficiency and minimizing the negative impact on the environment, a new coated controlled-release fertilizer with the function of water retention was prepared. A novel low water solubility macromolecular fertilizer, poly(dimethylourea phosphate) (PDUP), was "designed" and formulated from N,N'-dimethylolurea (DMU) and potassium dihydrogen phosphate. Simultaneously, an eco-friendly superabsorbent composite based on wheat straw (WS), acrylic acid (AA), 2-acryloylamino-2-methyl-1-propanesulfonic acid (AMPS), and N-hydroxymethyl acrylamide (NHMAAm) was synthesized and used as the coating to control the release of nutrient. The nitrogen release profile and water retention capacity of the product were also investigated. The degradation of the coating material in soil solution was studied. Meanwhile, the impact of the content of N-hydroxymethyl acrylamide on the degradation extent was examined. The experimental data showed that the product with good water retention and controlled-release capacities, being economical and eco-friendly, could be promising for applications in agriculture and horticulture.

Estimation of the storage life of dimethylol urea using non-isothermal accelerated testing

Abstract The mechanism and stability of dimethylol urea (DMU) to polycondensation were investigated using thermogravimetric analysis coupled with mass spectroscopy (TG-MS) for evolved gas analysis and a non-isothermal model-free induction period kinetic analysis using three temperature functions; the Arrhenius function and two non-Arrhenian functions. The polycondensation was observed to occur through a two-step process of condensation followed by elimination of formaldehyde during structural rearrangement as has been reported in the literature. The rate equations for each temperature function were evaluated and extrapolated to room (23 °C) and refrigerator (4 °C) temperature to estimate the length of the induction period for the onset of polycondensation for storage life prediction. Based on experience, estimates of the length of the induction periods and, hence, storage life, were most realistically predicted by the non-Arrhenian temperature functions.

Systematic choice of crosslinker and filler for pervaporation membrane: A case study with dehydration of isopropyl alcohol–water mixtures by polyvinyl alcohol membranes

Poly vinyl alcohol (PVOH) membrane, was crosslinked with 2, 4 and 6 mass% of four different kinds of crosslinkers i.e. glutaraldehyde (GLU), oxalic acid (OA), dimethylol urea (DMU) and tetra ethyl ortho silicate (TEOS) to produce four different kinds of crosslinked PVOH membranes termed here as PVGLU, PVOA, PVDMU and PVTEOS membrane, respectively. These membranes were first used for pervaporative separation of azeotropic feed concentration of 87.7 mass% of isopropyl alcohol (IPA) in water. Among all of these membranes PVOH membrane crosslinked with 2 mass% (of PVOH) GLU i.e. PVGLU2 was found to show optimum flux and water selectivity (79.75 g/m 2 h and 45.23, respectively, at 40 °C) for separation of this IPA–water azeotropic mixture. This PVGLU2 membrane was further filled with 2, 4, and 6 mass% hydrophilic aluminosilicate filler to produce three different filled membranes i.e. F2PVGLU2, F4PVGLU2 and F6PVGLU2, respectively. These three filled membranes were used for separation of the same azeotropic IPA–water mixtures and F6PVGLU2 membrane was found to show optimum flux and selectivity (109.84 g/m 2 h and 72.71, respectively, at 40 °C). This F6PVGLU2 membrane crosslinked with 2 mass% glutaraldehyde and filled with 6 mass% aluminosilicate filler showing optimum flux and selectivity for azeotropic IPA–water mixture was used for dehydration of IPA using IPA–water mixtures containing 75.87–99.36 mass% IPA in water. All of the filled and unfilled membranes synthesized were also characterized by various conventional methods.

Glass Reinforcement of Various Epoxy Resin (Dimethylolurea-Phenol Resin) Systems

N,N′-dimethylolurea (DMU) was prepared and condensed with phenol (P) in the presence of an alcoholic alkali catalyst using 1:1 mole ratio of DMU:P. The resultant DMUP resin was characterized by elemental analysis, IR spectral studies and number average molecular weight estimates by nonaqueous conductometric titration. Further reaction of DMUP resin was carried out with the three epoxy resins DGEBA, DGEBC and DGEBF. The curing of the prepared resins was monitored by differential scanning calorimeter (DSC) and their kinetic parameters have been evaluated. Based on DSC thermograms, glass fiber-reinforced composites have been laminated and characterized by chemical, mechanical and electrical properties. The unreinforced cured resins were subjected to thermogravimetric analysis (TGA).

Alkali pretreatment and resin finishing of lyocell: Effect of sodium hydroxide pretreatments

AbstractLyocell fabric samples were pretreated with 2–8 mol/L sodium hydroxide (NaOH) and then resin‐finished with dimethyloldihydroxyethylene urea, dimethyl dihydroxyethylene urea, and dimethylol urea based products. The resin‐finishing treatments caused changes in the substrate properties, such as reduced accessibility, improved crease recovery, and reduced work of rupture and abrasion resistance. Differences were observed between resin‐finished substrates as a function of the crosslinker type, and they were attributed to the influence of the crosslinker content and crosslink length in the substrates. The alkali pretreatments influenced the effects of resin finishing. A significant enhancement of the crosslinker penetration appeared within the substrates pretreated with 4 mol/L NaOH. Pretreatments with 6 and 8 mol/L NaOH also enhanced the crosslinker penetration, but the depth of catalyst penetration appeared to exceed that of the crosslinker; leading to demixing between the two components within the substrates. The penetration depth of a direct dye, C.I. Direct Red 81, appeared lower than that of the crosslinker in the alkali‐pretreated substrates. Pretreatments with NaOH in the range of 4–8 mol/L appeared to create gradients of accessibility within fibers and yarns of lyocell fabrics, with the depth of reagent penetration increasing in the following order: C.I. Direct Red 81 < crosslinker < catalyst. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Cleavage of blocked isocyanates within amino-type resins: Influence of metal catalysis on reaction pathways in model systems

In the present work, a detailed account on the deblocking reactions of various blocked isocyanates in aqueous reaction media in the presence of amido- and hydroxyl-nucleophiles is given. Pyrazole- and oxime-blocked phenylisocyanate were reacted with monomethylolurea (MMU), dimethylolurea (DMU) and urea (U) in the presence of the catalysts (dibutyltin dilaurate DBTL 1, zirconium(IV)dionate 2, zinc(II)acetate 3 and manganese (III)dionate 4). Product formation was studied by kinetic analysis of either the hydrolytic or the additive reaction pathways, revealing strong differences in the reactions pathways of the used catalysts. Both zirconium(IV)dionate 2 and DBTL 1 lead to the formation of N-phenyl-N′-carbamidurea and N,N′-diphenylcarbamidurea 15 as the preferred products after reaction with urea as nucleophile, whereas zinc(II)acetate and manganese(III)dionate indicated a significantly stronger promotion of hydrolytic reaction pathways. Zirconium(IV)dionate 2 catalyst proved advantageous over DBTL 1 displaying a lower deblocking temperature.

Synthesis, Characterization and Glass Reinforcement of Urea-Formaldehyde-Phenol Resins

N,N′-dimethylolurea (DMU) was prepared and condensed with phenol (P) in the presence of alcoholic alkali catalyst at varying mole ratios of DMU: P, namely 1:1, 1:1.5 and 1:2. The resultant DMUP resins were characterized by elemental analysis, IR spectral studies, number average molecular weight estimated by nonaqueous conductometric titration and thermogravimetry. The curing study of DMUP resins with hexamethylenetetramine (HEXA) was monitored by differential scanning calorimeter (DSC) and kinetic parameters were evaluated. Glass-reinforced composites based on DMUP-HEXA systems have also been prepared and characterized for chemical, mechanical and electrical properties.