Molybdenum Dioxide And Molybdenum Trioxide

Molybdenum Dioxide, is a kind of brown-black powder with steel shiny purple. The density of Molybdenum Dioxide is 6.44 g/cm3, we can get Molybdenum when heat the Molybdenum Dioxide  with hydrogen the temperature is above 500℃. And generate Molybdenum Oxychloride reaction with chlorine, and hydrogen chloride, alkaline,acid reaction. And it is very slightly soluble in Sulfuric Acid, Nitric Acid and Silver Nitrate. Oxidation of Molybdenum Dioxide can get Molybdenum Trioxide. Can be made of metal Molybdenum in steam heating, or heating to 470 ℃ MoO3 in hydrogen reduction of. Used in producing Molybdenum and other Molybdenum compounds.

Molybdenum is a silver-white metallic powdered Molybdenum gloss black, the melting point of it is 2610℃, the boiling point of it is 5560℃, the density of it is 10.2g/cm3. Molybdenum is very stable at room temperature in air, when the temperature was raised to 600℃, quickly react with oxygen to produce the more volatile Molybdenum Trioxide. At 500 to 1150 ℃ reduction with hydrogen trioxide or Ammonium Molybdate , Molybdenum can be available. MoO3 molecular weight of 143.94. White transparent rhombic crystals, to yellow when heated, cooled and restore the original color. Density 4.692g/cm3, melting point 795 ℃, boiling point 1155 ℃, easy sublimation. Insoluble in water, can be melted in a solution of ammonia and alkali generated Molybdate. Dissolved in acid, Molybdenum Dioxide generated root (MoO22 +) and Molybdenum Oxide root (MoO4 +) complex cation to form a soluble complex with the acid group. Oxidizing very weak at high temperature may be hydrogen, carbon, aluminum reduction. Reagents for the analysis, Molybdenum and Molybdenum alloy salt preparation. Ignition or Molybdenum or Molybdenum Disulfide to obtain calcined in air Molybdate.

While the Molybdenum Dioxide is different from Molybdenum Trioxide, it has two oxygen atoms, Molybdenum Dioxide, brown black powder, with steel shiny purple. Oxidation of it is very weak, at high temperature can be hydrogen, carbon, aluminum reduction. Used as an analytical reagent, preparation of Molybdenum and Molybdenum salt. Burning Molybdenum or Molybdenum Disulfide in air or roasting Molybdenum prepared.

Polyvinyl Alchol PVA 1788 and PVA 1799

Architectural coatings commonly use Polyvinyl Alcohol PVA 1788 and PVA 1799. Polyvinyl Alcohol is derived from the hydrolysis of Polyvinyl Acetate, and can not derived by the polymerization of Vinyl Alcohol. Because Vinyl Alcohol is very unstable, there can be no free Vinyl Alcohol Monomer. The formula of Polyvinyl Alcohol is (CH2CH)OH, wherein the degree of hydrolysis and degree of polymerization has a great influence on the physical properties of Polyvinyl Alcohol. The polymerization degree of the Polyvinyl Alcohol can be divided into a high polymerization degree, medium polymerization degree and low degree of oligomerization, and recently, the development of an ultra-high degree of polymerization products.

There are three typically kinds of alcoholysis, namely, 78 %, 88 % and 98 %. The complete alcoholysis of Polyvinyl Alcohol is 98 % to 100 %, partial alcoholysis of alcoholysis typically is 87 % to 89 %. For convenience, we often fetching thousands of polymerization degree, rounded at the front, percentages in the back alcoholysis. Therefore, PVA 1788 means that polymerization is 1700, with diethylene glycol 88 %, PVA 1799 means that polymerization is 1700, with diethylene glycol 99 %.

PVA 1788 is with good water solubility, whether in cold water, was quickly dissolved in hot water, but PVA 1799 only dissolves in hot water at 95 ℃ or above. Due to Polyvinyl Alcohol PVA to neutral, at the time of dissolution does not need special corrosion requirements, but it’s best to use stainless steel or enamel reaction kettle, because these materials will not rust and contamination of the solution.

PolyvinylAlcohol PVA 1788 and PVA 1799 can be used for emulsion polymerization of Vinyl Acetate emulsion stabilizer. Polyvinyl Alcohol can be used in the manufacturing of water-soluble adhesives, and can be used as modification of starch adhesive agents. And also can be used to preparation of photosensitive adhesive and benzene class solvent resistant sealant. Polyvinyl Alcohol also can be used as release agents, dispersants and so on.