Journal articles on the topic 'Melamine Solubility'
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1
Vanachayangkul, Pattaraporn, and William H. Tolleson. "Inhibition of Heme Peroxidases by Melamine." Enzyme Research 2012 (July 18, 2012): 1–7. http://dx.doi.org/10.1155/2012/416062.
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In 2008 melamine-contaminated infant formula and dairy products in China led to over 50,000 hospitalizations of children due to renal injuries. In North America during 2007 and in Asia during 2004, melamine-contaminated pet food products resulted in numerous pet deaths due to renal failure. Animal studies have confirmed the potent renal toxicity of melamine combined with cyanuric acid. We showed previously that the solubility of melamine cyanurate is low at physiologic pH and ionic strength, provoking us to speculate how toxic levels of these compounds could be transported through the circulation without crystallizing until passing into the renal filtrate. We hypothesized that melamine might be sequestered by heme proteins, which could interfere with heme enzyme activity. Four heme peroxidase enzymes were selected for study: horseradish peroxidase (HRP), lactoperoxidase (LPO), and cyclooxygenase-1 and -2 (COX-1 and -2). Melamine exhibited noncompetitive inhibition of HRP , and LPO showed a mixed model of inhibition . The inhibition of HRP and LPO was confirmed using a chemiluminescent peroxidase assay. Melamine also exhibited COX-1 inhibition, but inhibition of COX-2 was not detected. Thus, our results demonstrate that melamine inhibits the activity of three heme peroxidases.
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Wiwanitkit, Somsri, and Viroj Wiwanitkit. "Solubility of melamine crystal in different pH conditions: Clinical implication for management of melamine intoxication." Saudi Journal of Kidney Diseases and Transplantation 24, no. 5 (2013): 1019. http://dx.doi.org/10.4103/1319-2442.118081.
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Czél, György, A. Kelemen, and D. Solyom. "Flame Retardant Polyethylene Terephthalate Fibers Added with Melamine Based FR Additive." Materials Science Forum 659 (September 2010): 135–40. http://dx.doi.org/10.4028/www.scientific.net/msf.659.135.
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Polyethylene terephtalate (PET) was modified with a melamine derivative additive in order to obtain flame resistance of fiber products. The effect of flame retardant (FR) agent was determined by measuring rheological and combustion properties of PET linear polyester. The solubility of additive was investigated using a torque-rheometer. In course of the rheological investigation, the rate of solution was determined. The effect of FR additive on the melt rheology could well be traced by using a torque-rheometer and its evaluation method. After preparation of polyethylene terephtalat and melamine mixture melt, fibers were made by coextrusion centrifugal apparatus. The flame retardancy of fibers were determined by standard combustion tests. These tests were performed in order to determine the oxygen index of fiber products. It was proven that a favourable degree of combustibility of PET can be obtained under the influece of adding melamine-derivative additive.
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Adam, Nicole, Katja Hinz, Xavier Gaona, Petra J. Panak, and Marcus Altmaier. "Impact of selected cement additives and model compounds on the solubility of Nd(III), Th(IV) and U(VI): screening experiments in alkaline NaCl, MgCl2 and CaCl2 solutions at elevated ionic strength." Radiochimica Acta 109, no. 6 (May 14, 2021): 431–43. http://dx.doi.org/10.1515/ract-2021-1010.
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Abstract The solubility of Nd(III), Th(IV) and U(VI) was studied from undersaturation conditions in the presence of selected organic cement additives and model compounds: adipic acid, methyl acrylate, citric acid, melamine, ethylene glycol, phthalic acid and gluconic acid. Experiments were performed under Ar atmosphere in NaCl (2.5 and 5.0 M), MgCl2 (1.0 and 3.5 M) and CaCl2 (1.0 and 3.5 M) solutions with 9 ≤ pHm ≤ 13 (pHm = −log[H+]). Initial concentrations of organic ligands in solution were set constant in all systems to [L]0 = 0.025 M, except in specific cases (e.g. adipic acid, melamine and phthalic acid) where the ligand concentration in the matrix solutions was lower and controlled by solubility. Adipic acid, methyl acrylate, melamine, ethylene glycol and phthalic acid do not impact the solubility of Nd(III), Th(IV) and U(VI) in the investigated NaCl, MgCl2 and CaCl2 systems. Citrate significantly enhances the solubility of Nd(III), Th(IV) and U(VI) in NaCl systems. A similar effect was observed for Th(IV) and U(VI) in the presence of gluconate in NaCl systems. The impact of pH on the stability of the complexes is different for both ligands. Because of the larger number of alcohol groups in the gluconate molecule, this ligand is prone to form more stable complexes under hyperalkaline conditions that likely involve the deprotonation of several alcohol groups. The complexation of gluconate with U(VI) at pHm ≈ 13 is however weaker than at pHm ≈ 9 due to the competition with the highly hydrolysed moiety prevailing at pHm ≈ 13, i.e. UO2(OH)4 2−. The impact of citrate and gluconate in MgCl2 and CaCl2 systems is generally weaker than in NaCl systems, expectedly due to the competition with binary Mg-L and Ca-L complexes. However, the possible formation of ternary complexes further enhancing the solubility is hinted for the systems Mg/Ca-Th(IV)-GLU and Ca-U(VI)-GLU. These observations reflect again the differences in the complexation properties of citrate and gluconate, the key role of the alcohol groups present in the latter ligand, and the importances of interacting matrix cations. The screening experiments conducted within this study contribute to the identification of organic cement additives and model compounds potentially impacting the solution chemistry of An(III)/Ln(III), An(IV) and An(VI) under intermediate to high ionic strength conditions (2.5 ≤ I ≤ 10.5 M). This shows evident differences with respect to investigations conducted in dilute systems, and thus represents a very relevant input in the safety assessment of repositories for radioactive waste disposal where such elevated ionic strength conditions are expected.
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Zhao, Gui Xin, and Gou Sheng Liu. "Ammonium Polyphosphate with Crystal Form V by DAP+P2O5." Advanced Materials Research 306-307 (August 2011): 713–16. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.713.
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Ammonium polyphosphate (APP) is a widely used intumescent flame retardant ingredient, it has six crystalline forms, APP-V is seldom studied in literature. In this study, APP-V was prepared by process of diammonium phosphate (DAP)+P2O5as raw material, and melamine as condensation agent under dry ammonia. Its properties such as water solubility was tested and compared with APP-II. Further characteristics techniques such as FTIR, XRD, and TGA were used to characterize this product.
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Sukul, Pradip Kumar, Puspendu Das, Gopal Lal Dhakar, Lalmohan Das, and Sudip Malik. "Effect of Tricarboxylic Acids on the Formation of Hydrogels with Melem or Melamine: Morphological, Structural and Rheological Investigations." Gels 8, no. 1 (January 10, 2022): 51. http://dx.doi.org/10.3390/gels8010051.
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Herein, aggregation behaviors of melem or melamine in the presence of three symmetric carboxylic acids (1,3,5-tris(4-carboxyphenyl)benzene (TPCA), 1,3,5-benzene-tri-carboxylic acid (BTA) and 1,3,5-cyclohexane-tri-carboxylic acid (CHTA)) have been performed to check the influence of acid on the formation of aggregated structures which have been investigated by optical microscopy, FESEM, FTIR, XRD and viscoelastic properties have been explored with rheological studies. Interestingly, melem, that has limited solubility in aqueous medium, forms aggregation that leads to the formation of hydrogels with TPCA. More significantly, hydrogel is formed here by matching the size selectivity. Melem forms hydrogel with only large tricarboxylic acid, whereas melamine produces hydrogel with any kind of its counterpart from small to large tricarboxylic acid derivatives. Present investigations and results provide the strategy of design of organic self-assembled materials having two component systems.
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Ashraf, Muhammad Naveed, Shahzad Maqsood Khan, Shahid Munir, and Rashid Saleem. "Synthesis of Formaldehyde Free Amino Resin to Produce Green Eco-Labelled Leather with Improved Retanning Properties." Journal of the American Leather Chemists Association 115, no. 4 (April 1, 2020): 132–39. http://dx.doi.org/10.34314/jalca.v115i4.3799.
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Formaldehyde has many applications in the chemical industry including synthesis of amino resins which are used in leather processing. After application in leather, these resins are hydrolyzed under certain conditions to release free formaldehyde which has high environmental concerns due to its proven carcinogenic effects. The objective of this work is to develop a formaldehyde free melamine-based resin to produce green leather with improved retanning properties and thermal stability. The optimum melamine resin was synthesized by condensing melamine with glyoxal instead of formaldehyde. Further, the water solubility and improved thermal stability of synthesized melamine resins were achieved by introduction of sulfanilic acid in resin structure. Synthesized resin was used in leather retanning in comparison with commercially available melamine resin as a control. Both leathers were tested for mechanical properties, organoleptic properties, grain surface and fiber structure analysis. Comparative free formaldehyde content was measured in resultant leathers. Effluents of retanning baths were comparatively analyzed. Optimum resin was also characterized by thermo gravimetric analysis and FTIR. The results of this study showed that the experimental resin has imparted significant improvement in mechanical and organoleptic properties of leather as compared to the control resin. Analysis of free formaldehyde content confirmed the absence of free formaldehyde in leather treated with optimum resin while 141 mg/kg formaldehyde was detected in leather treated with control resin. Free formaldehyde was also absent in effluent of experimental resin while 305 mg/kg formaldehyde was detected in effluent of control resin. Moreover, percentage efficiency in COD, TDS and TSS load of effluent was observed as 9.62, 7.2 and 6.31 respectively. Resultant leather was free from formaldehyde making it safe for human along with reduction in pollution load of tannery.
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Martin, David, Martin Prostredný, and Ashleigh J. Fletcher. "Effect of Aromatic Amines on the Properties of Formaldehyde-Based Xerogels." Gels 6, no. 1 (March 2, 2020): 8. http://dx.doi.org/10.3390/gels6010008.
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This study investigates the synthesis of formaldehyde-based xerogels using alternative aromatic precursors, with comparison to traditional resorcinol-formaldehyde analogues, in order to alter the chemical composition of the resulting gels. By replacing resorcinol with aromatic amine molecules, i.e., ammeline, melamine and melem, each expected to undergo similar reactions with formaldehyde as the substituted species, we found that for all substituted gels, at low additive contents, the gel structure was compromised and non-porous materials were formed, as opposed to the most abundant monomers, and therefore, these additives seem to act as impurities at low levels. Working towards higher additive contents, melem monomers exhibited low solubility (~5%), even at elevated temperatures, thereby limiting the range to which melem could act as a substitute, while melamine could be incorporated up to ~40% under acidic conditions, with enhanced microporosity over this range. Pure gels were successfully synthesised from ammeline, but their performance was inferior to resorcinol-formaldehyde gels, while melamine-formaldehyde analogues required acidic reaction conditions but shrank considerably on sub-critical drying, adversely affecting the gel properties and demonstrating their lack of potential as sorbents. This demonstrates the potential for the inclusion of aminated aromatics within resorcinol-based gel systems, however, only as partial substitutes and not complete replacements.
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Fan, Kaiqi, Libo Niu, Jingjing Li, Rongxiu Feng, Rui Qu, Tianqi Liu, and Jian Song. "Application of solubility theory in bi-component hydrogels of melamine with di(2-ethylhexyl) phosphoric acid." Soft Matter 9, no. 11 (2013): 3057. http://dx.doi.org/10.1039/c3sm27421g.
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Zhang, Ziming, Qiang Cai, Jiadan Xue, Jianyuan Qin, Jianjun Liu, and Yong Du. "Co-Crystal Formation of Antibiotic Nitrofurantoin Drug and Melamine Co-Former Based on a Vibrational Spectroscopic Study." Pharmaceutics 11, no. 2 (January 30, 2019): 56. http://dx.doi.org/10.3390/pharmaceutics11020056.
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The co-crystallization of active pharmaceutical ingredients (APIs) has received increasing attention due to the modulation of the relative physicochemical properties of APIs such as low solubility, weak permeability and relatively inferior oral bioavailability. Crystal engineering plays a decisive role in the systematic design and synthesis of co-crystals by means of exerting control on the inter-molecular interactions. The characterization and detection of such co-crystal formations plays an essential role in the field of pharmaceutical research and development. In this work, nitrofurantoin (NF), melamine (MELA) and their hydrated co-crystal form were characterized and analyzed by using terahertz time-domain spectroscopy (THz-TDS) and Raman vibrational spectroscopy. According to the experimental THz spectra, the hydrated co-crystal form has characteristic absorption peaks at 0.67, 1.05, 1.50 and 1.73 THz, while the THz spectra for the two raw parent materials (NF and MELA) are quite different within this spectral region. Similar observations were made from the experimental Raman vibrational spectra results. Density functional theory (DFT) calculation was performed to help determine the major vibrational modes of the hydrated co-crystal between nitrofurantoin and melamine, as well as identify the structural changes due to inter- and/or intra-molecular hydrogen bonding motifs between NF and MELA. The results of the theoretical frequency calculations corroborate the THz and Raman experimental spectra. The characteristic bands of the NF–MELA-hydrated co-crystal between nitrofurantoin and melamine were also determined based on the DFT simulated calculation. The reported results in this work provide us with a wealth of structural information and a unique vibrational spectroscopic method for characterizing the composition of specific co-crystals and inter-molecular hydrogen bonding interactions upon pharmaceutical co-crystallization.
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Zanetti, M., A. Pizzi, M. Beaujean, H. Pasch, K. Rode, and P. Dalet. "Acetals-induced strength increase of melamine-urea-formaldehyde (MUF) polycondensation adhesives. II. Solubility and colloidal state disruption." Journal of Applied Polymer Science 86, no. 8 (September 11, 2002): 1855–62. http://dx.doi.org/10.1002/app.11105.
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Dominguez-Estevez, Manuel, Anne Constable, Paolo Mazzatorta, Andrew G. Renwick, and Benoit Schilter. "Using urinary solubility data to estimate the level of safety concern of low levels of melamine (MEL) and cyanuric acid (CYA) present simultaneously in infant formulas." Regulatory Toxicology and Pharmacology 57, no. 2-3 (July 2010): 247–55. http://dx.doi.org/10.1016/j.yrtph.2010.03.002.
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Bretti, Clemente, Concetta De Stefano, Gabriele Lando, and Silvio Sammartano. "Thermodynamic properties of melamine (2,4,6-triamino-1,3,5-triazine) in aqueous solution. Effect of ionic medium, ionic strength and temperature on the solubility and acid–base properties." Fluid Phase Equilibria 355 (October 2013): 104–13. http://dx.doi.org/10.1016/j.fluid.2013.06.056.
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Li, Liangchuan, Ming Zhou, Long Jin, Youtang Mo, Enyong Xu, Huajin Chen, Lincong Liu, Mingyue Wang, Xin Chen, and Hongwei Zhu. "Green Preparation of Aqueous Graphene Dispersion and Study on Its Dispersion Stability." Materials 13, no. 18 (September 14, 2020): 4069. http://dx.doi.org/10.3390/ma13184069.
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The large-scale preparation of stable graphene aqueous dispersion has been a challenge in the theoretical research and industrial applications of graphene. This study determined the suitable exfoliation agent for overcoming the van der Waals force between the layers of expanded graphite sheets using the liquid-phase exfoliation method on the basis of surface energy theory to prepare a single layer of graphene. To evenly and stably disperse graphene in pure water, the dispersants were selected based on Hansen solubility parameters, namely, hydrophilicity, heterocyclic structure and easy combinative features. The graphene exfoliation grade and the dispersion stability, number of layers and defect density in the dispersion were analysed under Tyndall phenomenon using volume sedimentation method, zeta potential analysis, scanning electron microscopy, Raman spectroscopy and atomic force microscopy characterization. Subsequently, the long-chain quaternary ammonium salt cationic surfactant octadecyltrimethylammonium chloride (0.3 wt.%) was electrolyzed in pure water to form ammonium ions, which promoted hydrogen bonding in the remaining oxygen-containing groups on the surface of the stripped graphene. Forming the electrostatic steric hindrance effect to achieve the stable dispersion of graphene in water can exfoliate a minimum of eight layers of graphene nanosheets; the average number of layers was less than 14. The 0.1 wt.% (sodium dodecylbenzene sulfonate: melamine = 1:1) mixed system forms π–π interaction and hydrogen bonding with graphene in pure water, which allow the stable dispersion of graphene for 22 days without sedimentation. The findings can be beneficial for the large-scale preparation of waterborne graphene in industrial applications.
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Vakhitova, Liubov, Kostyantyn Kalafat, Viktoriia Plavan, Volodymyr Bessarabov, Nadezhda Тaran, and Glib Zagoriy. "Comparing the effect of nanoclays on the water-resistance of intumescent fire-retardant coatings." Eastern-European Journal of Enterprise Technologies 3, no. 6 (111) (June 18, 2021): 59–70. http://dx.doi.org/10.15587/1729-4061.2021.232822.
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This paper reports a study into the effect of nanoclays on the water-resistance of the intumescent system ammonium polyphosphate/melamine/pentaerythritol/titanium dioxide/polymer (ethylene vinyl acetate (EVA) or styrene acrylate (SA). It has been established that adding nanoclay to a coating based on ethylene vinyl acetate increases the fire resistance limit of a metal plate by 30 %, and to a coating based on styrene acrylate – by 50 %. At the same time, coatings that include the EVA polymer are characterized by greater fire-retardant efficiency and less water resistance than coatings containing the SA polymer. It has been shown that intumescent coatings, regardless of the nature of the polymer, under the conditions of 80 % humidity over 800 days their reduce fire-protective properties by an average of 10 %. The loss of coating fire resistance occurs due to the leaching of pentaerythritol, ammonium polyphosphate, and polymer degradation by hydrolysis. The admixtures of nanoclays with a high degree of exfoliation to the studied system create a barrier effect and maximize the chemical formulation of the intumescent coating. The fireproof properties of coatings with organically-modified montmorillonite admixtures are maintained or reduced to 5 % under the conditions of 80 % humidity over 800 days. It has been determined that the direct effect of water on the coating over a period of more than 2 days leads to a significant decrease in the swelling coefficient of intumescent coatings, regardless of the content of a nanoclay admixture in their composition. At the same time, the half-decay period of coatings without nanoclay, calculated on the basis of solubility constant in water, is 0.5 days. For coatings, which include the admixtures of organically-modified nanoclays, the half-decay period increases to 2 days. The results reported in this paper could be recommended for designing water-proof fire-resistant reactive-type nano-coatings with prolonged service life.
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Sokol, Sokol, Bul’bak, Nefyodov, Zaikin, and Tomilenko. "C- and N-bearing Species in Reduced Fluids in the Simplified C–O–H–N System and in Natural Pelite at Upper Mantle P–T Conditions." Minerals 9, no. 11 (November 18, 2019): 712. http://dx.doi.org/10.3390/min9110712.
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C- and N-bearing species in reduced fluids weree studied experimentally in C–O–H–N and muscovite–C–O–H–N systems and in natural carbonate-bearing samples at mantle P–T parameters. The experiments reproduced three types of reactions leading to formation of hydrocarbons (HCs) at 3.8–7.8 GPa and 800–1400 C and at hydrogen fugacity (fH2) buffered by the Fe–FeO (IW) + H2O or Mo–MoO2 (MMO) + H2O equilibria: (i) Thermal destruction of organic matter during its subduction into the mantle (with an example of docosane), (ii) hydrogenation of graphite upon interaction with H2‑enriched fluids, and (iii) hydrogenation of carbonates and products of their reduction in metamorphic clayey rocks. The obtained quenched fluids analyzed after the runs by gas chromatography-mass spectrometry (GC–MS) and electronic ionization mass-spectrometry (HR–MS) contain CH4 and C2H6 as main carbon species. The concentrations of C2-C4 alkanes in the fluids increase as the pressure and temperature increase from 3.8 to 7.8 GPa and from 800 to 1400 C, respectively. The fluid equilibrated with the muscovite–garnet–omphacite–kyanite–rutile ± coesite assemblage consists of 50–80 rel.% H2O and 15–40 rel.% alkanes (C1 > C2 > C3 > C4). Main N-bearing species are ammonia (NH3) in the C–O–H–N and muscovite–C–O–H–N systems or methanimine (CH3N) in the fluid derived from the samples of natural pelitic rocks. Nitrogen comes either from air or melamine (C3H6N6) in model systems or from NH4+ in the runs with natural samples. The formula CH3N in the quenched fluid of the C–O–H–N system is confirmed by HR–MS. The impossibility of CH3N incorporation into K-bearing silicates because of a big CH3NH+ cation may limit the solubility of N in silicates at low fO2 and hence may substantially influence the mantle cycle of nitrogen. Thus, subduction of slabs containing carbonates, organic matter, and N-bearing minerals into strongly reduced mantle may induce the formation of fluids enriched in H2O, light alkanes, NH3, and CH3N. The presence of these species must be critical for the deep cycles of carbon, nitrogen, and hydrogen.
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Bono, Awang, Kiam Beng Yeo, and Nancy Julius Siambun. "Melamine–Urea–Formaldehyde (MUF) Resin: The Effect of the Number of Reaction Stages and Mole Ratio on Resin Properties." Jurnal Teknologi, January 20, 2012. http://dx.doi.org/10.11113/jt.v38.508.
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Resin MUF yang boleh larut dalam air digunakan dengan meluas sebagai bahan pelekat dalam industri kayu, teknologi salutan, industri kertas dan merupakan bahan utama dalam penghasilan barangan dapur plastik. Sifat resin yang berbeza diperlukan dalam aplikasi yang berlainan. Sifat–sifat resin ini dipengaruhi oleh beberapa faktor iaitu nisbah mol antara formaldehid dengan melamina/urea pada setiap peringkat tindak balas dan bilangan peringkat tindak balas di mana sebatian amino ditindak balaskan. Sifat–sifat resin yang penting ialah kestabilan resin, kelarutan dalam air yang tinggi dan tempoh pengerasan yang pendek. Kajian lepas telah menghasilkan resin MUF dengan sifat–sifat ini, walau bagaimanapun ia tidak mempunyai kandungan melamina dan urea yang mencukupi, untuk menyeimbangi kos dan prestasi. Selain itu haba juga diperlukan untuk membantu memendekkan tempoh pengerasan resin. Dalam kajian ini, kesan perubahan formula ke atas sifat–sifat resin seperti kestabilan resin, kelarutan dalam dan tempoh pengerasan pada suhu bilik dikaji. Keputusan menunjukkan bahawa kestabilan resin meningkat apabila bilangan peringkat tindak balas dan kandungan melamina meningkat. Walau bagaimanapun tempoh pengerasan turut dipanjangkan. Formula ini mempunyai kandungan melamina dan urea yang mencukupi, di mana ia berkos rendah berbanding resin melamina-formaldehid (MF), tapi dengan prestasi yang baik. Kata kunci: Melamina-urea-formaldehid (MUF); urea; melamina; formaldehid MUF resin is widely used as an adhesive in wood industries, coating technology, paper industries and a main material in kitchenware production. In different application, various MUF resin properties are required. The MUF resin properties are affected by several factors, for example mole ratio of formaldehyde to melamine/urea at each reaction stage and number of reaction stages where the amino compounds are reacted. Previous researches have developed MUF resin with these properties, however the formulation lack sufficient amount of melamine or urea to balance the cost and performance. Furthermore, shorter curing period could only be obtained with the help of external heat. In this research, effects of formula variation on resin properties such as resin storage stability, solubility in water and curing period at room temperature are investigated. The results showed that in 3-reaction stage of MUF resin process, the ratio of formaldehyde to urea/melamine in each reaction stage has caused significant increases in MUF resin curing period, solubility in water and resin storage stability. These formulations contains sufficient amount of melamine and urea, which lowered the cost and yet maintaining good performance as compared to melamine–formaldehyde (MF) resin. Key words: Melamine-urea-formaldehyde (MUF); urea; melamine; formaldehyde
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"Assembly Study of Melamine and its Derivatives." International Journal of Organic and Inorganic Chemistry, August 25, 2018, 1–3. http://dx.doi.org/10.31829/2768-0320/chemistry2018-1(1)-e103.
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Melamine is well established nitrogen rich triazine ring containing molecule with three additional nitrogen atoms those can easily protonate and enhance the solubility of polar solvents [1]. Recently, derivatization of melamine gained the significant advanced for variety of purposes including corrosion inhibition. Literature survey revealed that melamine and its several derivatives have been investigated as effective corrosion inhibitors for metals and alloys in aggressive solutions owing to their high protection ability which is in turn attributed to the adsorption of these compounds by their protonizable amino groups and non-bonding electrons of nitrogen atoms and π-electrons of three double (-C=N- ) bonds [2,3]. Melamine is a nontoxic, white, odorless hetero-aromatic substance, which is used as a raw material for various industrial products, mostly as a high molecular weight compound obtained from reaction with formaldehyde. Melamine formaldehyde (MF) resins are obtained by poly-condensation of melamine with formaldehyde in acidic or basic media [4].
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Цой, Ю. И. "In the stability of paints and varnishes for protective and decorative wood finish." Известия СПбЛТА, no. 215(215) (June 28, 2016). http://dx.doi.org/10.21266/2079-4304.2016.215.244-254.
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Задача получения однородного состава ЛКМ сводится к правильному выбору пленкообразователей и соответствующих растворителей и, в случае необходимости, разбавителей и добавок. На основе положений теории растворимости была проведена оценка совместимости компонентов и стабильности таких систем. Критериями оценки были приняты параметры растворимости и термодинамического взаимодействия. Исследовали совместимость алкидных лаков с аминоформальдегидными смолами в бутаноле, и результаты этих исследований представлены в треугольной фазовой диаграмме. Для оценки совместимости смол по результатам расчета параметров термодинамического взаимодействия были построены спинодали для тройных систем. Как показывает анализ результатов проведенных исследований, даже при большой разности ?? = |?12 – ?13| = 0,2 наблюдается небольшая область несовместимости. С уменьшением разности ?? область несовместимости сужается. При ?23 > ?с область несовместимости расширяется как для ? = 0,2, так и для ?? = 0,1 и ?? = 0. Таким образом, для таких систем на совместимость компонентов, в первую очередь, влияет их взаимодействие между собой – чем оно больше, тем лучше они совместимы. Проведенные исследования показали, что парциальные параметры растворимости, учитывающие природу когезионных сил, более объективно характеризуют растворимость пленкообразующих смол в органических растворителях, чем их общий параметр растворимости. Растворимость пленкообразующих алкидных и этерифицированных аминоформальдегидных смол в органических растворителях обусловлена термодинамическим взаимодействием молекулярных сил различной природы. Стабильность смеси алкидной и этерифицированной аминоформальдегидной смолы в бутаноле обусловлена в большей степени термодинамическим взаимодействием молекулярных сил; при этом степень бутанолизации меламиноформальдегидной смолы оказывает наибольшее влияние на стабильность cистемы. Проведенные исследования по стабильности лакокрасочных смесей из различных пленкообразующих смол на основе рассмотренных критериев оценки могут быть использованы для совершенствования технологии защитно-декоративной отделки древесины. The problem of obtaining a homogeneous composition of the coatings is reduced to the proper selection of film-forming agents, and diluent and, if appropriate, diluents and additives. On the basis of the theory of solubility, we have carried out the assessment of the compatibility of the components and stability of such systems. The evaluation criteria were adopted the parameters of the solubility and thermodynamic interaction. Researched the compatibility with alkyd varnishes aminoformaldehyde resin in butanol, and the results of these studies are presented in the triangular phase diagram. To evaluate the compatibility of the resins according to the results of calculation of thermodynamic parameters of interaction were built spinodal for ternary systems. As the analysis of the results of the studies, even when the difference ??|?12 – ?13| = 0,2 there is a small area of incompatibility. With the decrease of the difference ? ? region incompatibility narrows. When ?23> ?с region incompatibility extends to ?? = 0,2, and for ?? = 0.1 and ?? = 0. Thus, for such systems, compatibility of components, primarily, affects their interaction with each other – the further away it is, the better they are compatible. Studies have shown that the partial solubility parameters, which take into account the nature of cohesive forces, more objectively characterize the solubility of film-forming resins in organic solvents than their total solubility parameter. The solubility and film-forming aminoformaldehyde esterified alkyd resins in organic solvents due to thermodynamic interaction of molecular forces of different nature. Тhe stability of the mixture and aminoformaldehyde esterified alkyd resin in butanol is generated largely by thermodynamic forces of molecular interaction; the degree of butanolate melamine-formaldehyde resin has the greatest effect on the stability of the system. Conducted research on the stability of the paint mixtures of various film-forming resins on the basis of the evaluation criteria can be used to improve the technology of protective and decorative wood finish.
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Claudius D' Silva. "A Facile Route to Melaminophenyl Boronates using 2, 4-Diazido-6- Chloro-1, 3, 5-Triazine as an Electrophilic Reagent." Organic Chemistry Plus, February 7, 2021, 1–6. http://dx.doi.org/10.37256/ocp.212021716.
Full textAbstract:
We have synthesised a novel class of melaminyl derivative, containing a phenyl boronate or boronate ester group. The synthetic methodology employed was designed to be facile involving the use of 2, 4-diazido-6-chloro-1, 3, 5-triazine as an electrophilic reagent for nucleophilic substitution of chlorine with a weakly reactive amine. The reagent was chosen with a view to improve the organic solubility of the product and aid isolation by allowing the reaction to be followed by fluorescence quenching (Tlc, F234) and IR (the presence of two N3 peaks).