- Synthesis of N-trinitroethyl derivatives of linear and heterocyclic nitrogen-containing compounds
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Earlier unknown N-trinitroethyl derivatives of acetylhydrazine, 4-amino-1,2,4-triazole, and 2,4,6-triamino-1,3,5-triazine, which are potential components for gas-generating formulations, were synthesized.
- Ovchinnikov,Kulikov,Epishina,Makhova,Tartakovsky
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- Synthesis of 2,4,6-tris(2,2,2-trinitroethylnitramino)-1,3,5-triazine
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An alternative procedure for synthesizing 2,4,6-tris(2,2,2-trinitroethylamino)-1,3,5-triazine was developed. Nitration of this compound gave hitherto unknown 2,4,6-tris(2,2,2-trinitroethylnitramino)-1,3,5-triazine, which is of interest as potential component of solid rocket fuel compositions.
- Korepin,Shastin,Glushakova,Kosilko,Malygina,Lagodzinskaya,Lodygina
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- The influence of silicone shell on double-layered microcapsules in intumescent flame-retardant natural rubber composites
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Double-shell co-microencapsulated ammonium polyphosphate and mesoporous MCM-41 (M(A&M)) were prepared by using melamine-formaldehyde resin and organic silicon in situ polymerization. The structure of the microcapsules was characterized by Fourier-transform infrared spectroscopy, particle size analysis, and scanning electron microscopy. In particular, the influence of basic properties of flame-retardant natural rubber, such as flame-retardant and mechanical property, was investigated with the limiting oxygen index, UL-94 test, thermogravimetric analysis, tensile test, and rubber process analyzer (RPA). Due to the presence of organic silicone shell, the NR/M(A&M) composites had much better flame-retardant and mechanical properties than other flame-retardant natural rubber (NR) composites. The limited oxygen index value of the NR/M(A&M) composite reached the maximum, and the UL-94 ratings were increased to V-0. Furthermore, M(A&M) showed better compatibility in NR system by the RPA. The occurrence of a synergistic effect between MCM-41 and intumescent flame-retardant in the NR composites was proved. As a result, the thermal stability and flame retardancy of NR were enhanced.
- Wang, Na,Wu, Yuhu,Mi, Long,Zhang, Jing,Li, Xuri,Fang, Qinghong
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- Effect of graphene on the thermophysical properties of melamine-urea-formaldehyde/N-hexadecane microcapsules
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Heat transfer performance remains a key factor for the potential application of microencapsulated phase change materials (microPCMs). The purpose of this work is to explore the effect of different amounts of graphene added on the thermophysical properties of microPCMs. Microcapsules containing n-hexadecane (C16) with a melamine-urea-formaldehyde (MUF) shell were synthesized by emulsion polymerization. The spectra of Fourier transform infrared spectroscopy (FTIR) confirmed that the MUF shell is fabricated on the surface of C16. Graphene is successfully mixed with microPCMs and the crystal type of microPCMs is not changed, which is detected by X-ray Diffraction (XRD). The results indicated that heat enthalpy of microPCMs gradually decreases with the rising addition of graphene, but the heat transfer performance and thermal stabilities are enhanced. In addition, graphene in microPCMs obviously reduces the degree of supercooling of C16. MicroPCMs with 0.05 wt% added graphene have the best anti-osmosis performance.
- Wu, Bingyang,Zheng, Guo,Chen, Xu
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- Microencapsulation of ammonium polyphosphate with melamine-formaldehyde-tris(2-hydroxyethyl)isocyanurate resin and its flame retardancy in polypropylene
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Microencapsulated ammonium polyphosphate with a novel melamine-formaldehyde-tris(2-hydroxyethyl)isocyanurate resin (MFT resin) was prepared by in situ polymerization. This microencapsulated ammonium polyphosphate was named MFT-APP. The MFT resin and MFT-APP were characterized by FTIR, XPS, TGA and SEM. Polypropylene (PP)/MFT-APP and PP/MFT-APP/THEIC were prepared. Their thermal stability and flame retardancy were investigated through TGA, limiting oxygen index (LOI), vertical burning tests and cone calorimeter tests. SEM was used again to observe the morphology of char residues. The results illustrated that MFT-APP and MFT-APP/THEIC had excellent flame retardant properties on PP. Furthermore, a water resistant test demonstrated that PP/MFT-APP/THEIC had better flame durability than PP/APP/THEIC. TGA-FTIR and XPS results revealed that the efficient flame retardancy of MFT-APP/THEIC was mainly attributed to the formation of a compact and thermostable intumescent char on underlying materials during a fire.
- Jiang, Ziwei,Liu, Gousheng
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- Improved performance of soy protein adhesive with melamine-urea-formaldehyde prepolymer
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In recent years, soy protein adhesive, as an environmentally friendly bio-based adhesive, has attracted extensive attention. In this study, in order to ameliorate the bonding quality of soy protein isolate (SPI) adhesive, the melamine-urea-formaldehyde prepolymer (MUFP) was synthesized, and different amounts of it were introduced into the SPI adhesive as a cross-linking agent. Fourier transform infrared (FT-IR) spectroscopy, gel permeation chromatography (GPC), thermogravimetric analyze (TGA), and scanning electron microscopy (SEM) were used to analysis the mechanism of modification. The results of plywood test indicated that the wet bonding strength of the adhesives was first increased and then decreased with an increase in the amount of MUFP additive. FT-IR, TGA, and SEM tests suggested that the introduction of MUFP could promote the establishment of a cross-linking structure in the cured adhesive layer to improve the bonding quality of adhesives, but presence of excessive MUFP could introduce hydrophilic groups and adversely affect water resistance. This journal is
- Chen, Yuzhu,Feng, Qiaoling,Jiang, Ke,Jing, Mingwei,Lei, Zhenghui,Lv, Wenxin,Tan, Hailu,Xiao, Hui,Yi, Maoyu
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p. 27126 - 27134
(2021/08/24)
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- Preparation method of trimethylol melamine
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The invention discloses a preparation method of trimethylol melamine. The preparation method comprises the following steps: feeding a formaldehyde solution into a reaction kettle according to a mole ratio of melamine : formaldehyde : water of 1:(2.5-3.5):(8-30), and adding water and melamine in sequence for reaction by adjusting temperature and rotating speed. Compared with the conventional process, the preparation method has the advantages that the synthesis process is simple, and raw materials are readily available and easy to separate and purify; due to the reduction of raw material components, the production cost of trimethylol melamine is greatly reduced, the conversion rate of melamine is increased, and the formaldehyde content is reduced; meanwhile, resources are also saved, production of wastewater is reduced, and the environment is protected.
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Paragraph 0016-0035
(2017/06/02)
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- Particles with improved solubilization capacity
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A particle is disclosed that comprises a first volume of hydrophobe-rich material with tunable dissolution and solubilization characteristics and a distinct second volume of nanostructured nonlamellar liquid crystalline material, said second volume containing said first domain and being capable of being in equilibrium with said first volume. Preferably, the nanostructured nonlamellar liquid crystalline material is capable of being in equilibrium with a polar solvent or a water-immiscible solvent or both.
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- Composition of matter having bioactive properties
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Particles of coordinated complex comprising a basic, hydrous polymer and a capacitance adding compound, as well as methods for their production, are described. These complexes exhibit a high degree of bioactivity making them suitable for a broad range of applications through their incorporation into conventional vehicles benefiting from antimicrobial and similar properties.
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- Canonical Chemical Theories Exemplified by the Mehtylolation of Urea and Melamine
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Old and recent data on equilibria and kinetics of methylolation of urea and melamine are analysed.The theoretical framework affords a sequence, claimed to be canonical of successive phenomenological approximations.The theory, expounded earlier, begin with two successive schemes whose essentials go back to early work by Pauling and by Flory.The two stages here suffice to show that all the data from eight laboratories, covering the six-membered family of methylol ureas and rhe ten-membered family of methylol melamines, are in quantitative agreement, a circumstance unsespected by other workers in the field.The statisticalthermodynamic and kinetic principles involved are therefore expounded in more detail than before.Using them, very small substituent effects (e.g O.35 kJ kol-1 are deduced with high significance and accuracy.Owing largly to the recent measurement by Tomita, the methylol melamines are claimed currently to be the thermdinamically best characterised family in the chemical literature.A challenge arises for theoretical chemists to test quantum-theoreticaltechniques against the measured energetics of substituent effects in this family, and to exploit for other families the graph-theoretical analysis of molecular additivity which underlies the approximation schemes, which already well tested.
- Gebregiorgis, Taddesse,Gordon, Manfred
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p. 359 - 382
(2007/10/02)
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