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    Home > Coatings News > Paints and Coatings Market > Study on the modified nature of nitroculose

    Study on the modified nature of nitroculose

    • Last Update: 2021-01-02
    • Source: Internet
    • Author: User
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    China Coatings Online News Information
    Abstract: Nitrocil cellulose of different nitrifitrate degrees is being widely used in coatings, paints and plastics and other fields, with the changing market environment, the quality and function of nitrocil cellulose products continue to improve the requirements, products to achieve functionality, diversification and safety. Because nitroculose itself has hydroxy and nitrate-based, we can get very different performance modified nitroculose-related products, better used in the market through chemical and physical change methods such as latteing, crosslinking, shrinking, blending and so on.
    keywords: nitroculose; nitro paint; chemical modified; physically modified
    foreword
    cellulose D-furan glucose unit there are 3 hydroxyls, including one persohydroxygen and two medium hydroxyls, theoretically can occur hydroxyl-related most derivative reactions, resulting in one replacement, two substiration and three replacement cellulose derivatives. In the mid-19th century, nitroculose was accidentally discovered as the first cellulose ester in history and used for a long time in the military. To this day, nitroculose remains an irreplaceable and important material in the field of fire explosives.
    With the deepening of research, nitrocil cellulose is gradually widely used in the civil field, the current low viscosity of nitrocide cellulose is widely used in coatings (nitro paint), film materials and cosmetics, especially the use of low nitrogen nitrocline cellulose and plasticizer production of "Sai Wei" plastic widely appeared in chemical, aerospace, machinery, printing and dyeing, building materials, decoration, packaging, cosmetics, gift packaging and other fields. The national table tennis we use is made of "Sai Yi" plastic.
    the solubility and transparency of nitroculose used in the civil field, and the requirements for viscosity, stability and nitrogen content are more stringent. According to the characteristics of the current nitrocul cellulose market demand, improving the quality of its products is the main trend, increasing safety management efforts, regulating its storage and use is a new requirement, and continuing to develop its use towards more sophisticated, higher-end applications is also the key to this traditional material in the emerging new materials continue to be the "evergreen tree" in the field of materials.
    1 The physical change and application of nitroculose
    1.1 serotonin
    serotonin is a synthetic plastic made by mixing nitroculose with camphor, which was originally developed to replace ivory products and reduce the killing of wild elephants. The original synthesis was completed in 1869 and registered as a trademark in 1872, named "Sai Yi". The production process and equipment are simple and low price. The race is highly resistant to stress, acid, oil and water. The peak of the use of cystics occurred in the late 18th and early 19th centuries, but their flammable defects were quickly exposed and in many ways replaced by other new, more fire-resistant and safer synthetic polymeric materials. Even so, Seymru is still an indispensable and important member of today's plastic materials.
    1.2 water-based nitroculose coatings
    traditional nitroculose coatings have excellent properties, easy construction, fast drying, with better weather resistance, and are still widely used today. However, VOC is the largest solvent-based coating product and contains carcinogens such as benzene and benzene derivatives. With the enhancement of environmental awareness in society and the increasingly stringent national policies, traditional nitrocul cellulose coatings are facing great challenges. Reducing the use of organic solvents and water between them is the current trend of nitrocul cellulose coatings.
    contains only a small amount of organic solvents in water-based nitroculose coatings and can be used in the coating of metals, wood, leather and paper. Mix nitroculose with other resins, add plasticizers and surfactants, and disperse water into emulsions to make water-based nitroculose coatings, or their associated composite coatings. In this way, compared with traditional nitroculose coatings, VOC is greatly reduced, but the adhesion and low gentle toughness are poor, due to the introduction of emulsifying agents or hydro-friendly ingredients, the coating in water resistance, alcohol resistance performance has been lost, in general, still need to be further improved;
    at present, water-based polyurethane coatings are getting more and more attention, their construction is simple, the construction environment requirements are low, the coating performance is good, and will soon be widely used in all aspects. Despite its excellent performance, its poor degradation and fast-drying performance also constrain its longer-term growth. Nitroculose does not produce harmful chemicals in natural degradation, regeneration speed is very fast, while the traditional nitroculose coating fast-drying performance is very good, so the use of nitrocul cellulose and polyurethane mixed paint, nitroculose part of the replacement of polyurethane, the advantages of the combination of the two. Realizing less use of polyurethane, improving the environmental effect of polyurethane coatings, and improving the performance of coatings are realistic research directions. Some studies show that: nitrocul cellulose and polyurethane mixed modified paint has a better flexibility and strength, cold resistance, excellent thermal performance.
    1.3 nitroculose membrane
    nitroculose itself has good film-forming properties. In biological research, nitroculose membrane has a strong binding capacity to proteins, compatible with a variety of color-showing methods, low background noise, simple use, so it has become the most important transfer medium of protein imprinting.
    Although the high flammability of nitroculose membrane is obscured in this field, this excellent membrane material still shows the disadvantages of brittle, easy to roll, can not be repeated cleaning, still need further research to improve.
    of 1.4 nanometers of nitroculose
    in recent years, the excellent performance of nanoculose materials has gradually emerged, becoming one of the current hot materials. As a derivative of cellulose, the nanosis of nitroculose has received less attention. The reason may be that the current nitrocul cellulose material market performance under the siege of new materials under the long-term trend, and safety accidents frequently damage the community's confidence in this material, and ultimately reduce the research and development interest of researchers in this material. But for this unique material, it is still of practical significance to study its nano."
    has been reported that the nano-nitrate cellulose system is mainly electrostitration spinning method and nanoculcin crystal-spinning dispersion fluid nitrification. The former can make nano-nitroculose fibers with narrow diameter distribution, while the latter can make nano-nitroculose crystals. Both have greater reactive activity than surface area and better. When nitrification reaction is performed using nanoculose crystal dispersion fluid, the reaction rate is greatly increased due to the uniform dispersion of nanoculose crystal in water, which makes the reaction performance close to the homogenous, and the reaction rate is greatly increased under certain conditions, and the reaction is complete in only a few minutes under certain conditions.
    nano-nitroculose material inherits the original properties of nanoculose material, while maintaining its chemical properties. For pure nanoculose materials, its hydromassiveness is strong. In the production of composite materials as an enhanced phase only good compatible with water-based materials, in oily materials, poor performance of compatible not only can not express its ability to enhance, toughen, but weaken the material. Traditional coating research has shown good oil solubility characteristics of nitroculose, so it is very promising to nano-chemical nitroculose and make advanced composite materials with oily polymer materials.
    2 Chemical modified and applied
    2.1 nitrite hydroxyane ether modified
    cellulose is connected to the branch chain, branch chain small molecules of its internal plasticization effect, such as modified cellulose hydroxyl alkyl ether, with better molecular softness, nitrite products are a new type of energy-containing thermoplastic polymer. These include hydroxyethyl cellulose ether nitrate (NHEC), hydroxypropyloxyclyceride ether nitrate (NHPC), dihydroxyproxyl cellulose ether nitrate (NGEC) and trihydroxybutyl cellulose nitrate (NTHC). In molecular structure, hydroxyclyctic cellulose ether nitrate is more complex than nitrostrate. The reason is that cellulose after the etheric reaction on its glucose ring base (AGU) 2, 3, 6 bits of carbon will have a short branch chain, the branch chain with hydroxyl can continue to occur etheric reaction, the formation of short branch chain will reduce the original crystallization of cellulose, nitrification of the distribution of nitrate base is much more complex than NC. To know the structure and properties of the product, molecular design can be carried out theoretically, and then tested and analyzed for optimization.
    from the point of view of molecular structure, nitroculose belongs to the rigid polymer chain, and it is an effective way to improve the softness of its large molecular chain segment by changing. Britain's Stratton, russia Вершинин л.D. have modified nitroculose thing (thermoplastic soft segment) to improve its cryogenic properties. China's Tan Huimin used prepolymers by isocyanate-based polyether sealing end to modifie nitroculose, to obtain energy-containing adhesive, the results show that the new adhesive as the basis for the preparation of tablets, its performance has been greatly improved. Zhai Self-reinforcing and others used the method of first modified and then nitrified to obtain a new type of nitroculose modified material with superior thermoplastic properties. Due to the "internal plasticization" effect of small molecular branch chain, smokeless and homogenous gunpowder can be obtained without the use of traditional gunpowder plasticization technology, and the new gunpowder is a cold gunpowder with a thermal value of 800kcal/kg, and has high energy and excellent electromedicine elasticity, high density and good chemical stability, high combustion speed, and small dispersion, low moisture absorption, small corrosion, and stable physical properties.
    synthesis of nitroculose hydroxyl ether, first need to alkalinize cellulose to make alkali cellulose, and then through etheric agents and solvents to obtain cellulose hydroxyl ether, and then nitric acid esterification, to obtain nitroculose hydroxyl ether.
    2.2 Nitroculose Stacking Nitrogen Modified
    In order to meet the needs of modern warfare, energy-containing materials are developing in the direction of high density, high energy, bluntness and low characteristic signals. Among them, the superseed nitrogen plasticizer, the stacked nitrogen adhesive and the superficide nitrogen high-energy oxidants have been widely concerned, since the founding of the superficide nitrogen base in 1864, a lot of research has been done on the overlapping nitrogen compounds. The reason for this is that nitric compounds are used in emitters and propellants, not only with high energy levels, but also because they provide a positive standard generation of radon of about 356KJ/mol, and because the combustion product has a low molecular weight and does not generate smoke. It can not only improve the energy and combustion speed of the propellant, but also reduce the flame temperature and smoke signal of the propellant. And most of the nitrogen compounds have a lower impact and frictional sensitivity.
    cellulose large molecules contain only a stack of nitrogen-based groups, the performance of the material is poor, dissolving performance, processing performance can not meet the requirements of the application. Therefore, nitrocul cellulose, which contains a stack of nitrogen groups, is the direction of development.
    nitroculose laminated nitrogen modified methods are mainly the following methods:
    1) to toluene sulfonyl salt as a reaction intermediate, the preparation of overlapping nitrogen cellulose nitrate and laminated nitrogen cellulose glycerin ether nitrate.
    2) First of all, the nitrite treatment of cellulose or its hydroxyl alkyl ether, and then the use of nitroculose or nitroculose hydroxyl ether good solubility and nitrate-based departure performance, with a stack of nitrogen-based part of the pro-nuclear instead of the production of the target product.
    3) The etheric treatment of cellulose with etheric agent containing a stack of nitrogen-based groups is introduced, and then nitrification of this layered nitrogen cellulose ether
    3 methyl cellulose nitrate
    With the advent of the green century, the requirements of the green environment of coatings are becoming more and more stringent. Traditional nitro coatings in the high-end wood coating industry has irreplaceable advantages, but its existence of high pollution, high energy consumption, low solid content and other shortcomings seriously limit the development of environmentally friendly nitro coatings with two parents has become the main breakthrough direction of industry development.
    through chemical change, The methyl group and nitrate-based group into the cellulose molecular chain, thereby giving its two parents performance, nitrate-based oil affinity is good, in a certain range, improve the replacement degree of nitrate-based, can increase its dissolution in solvents;
    synthesis of methyl cellulose nitrate requires the preparation of low-replacement methyl cellulose, followed by nitrateization to prepare nitroculose nitrate.
    4 Cellulose acetate blend
    cellulose acetate nitrate blend (CAN) has many unique properties that differ from cellulose nitrate (NC) or cellulose acetate (CA) or the physical mixture of these two esters. Studies have shown that the extrusion strength and thermal stability of the mixed esters are much improved and can be used as a gel stabilizer in propellants. The addition of acetylase improves the stability of cellulose nitrates and has no effect on the combustion of cellulose nitrates, so some high nitrogen-containing cellulose acetate blends can be applied to the plastics, paint, film industry, breaking the limits of only low nitrogen fiber nitrates used in these industries, and bring low nitrogen content cellulose nitrate can not be comparable performance. In addition, the replacement of the remaining hydroxyl of cellulose nitrates with acetyl will improve the solubility of cellulose nitrates, thus increasing the mixing with a variety of plasticizers.
    cellulose acetate mixture has two synthetic ways, one is based on low nitrite cellulose as raw material, acetate ester preparation, and one is based on cellulose acetate as raw material, nitric acid esterification preparation.
    we believe that as research into nitroculose erration deepens, its use will become more and more extensive, after all, the nature of all-natural people will re-like it.
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