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PVA;polyvinyl alcohol
Structure-[CH2CH (OH)] n -
PVA is not governed by a monomer polymerization and Qualcomm Guo PVAc hydrolysis of the water-soluble polymers, referred to. Flake white, cotton-like powder or solid, dull. PVA by the physical nature of chemical structure, alcohol solution, the degree of polymerization of the impact. The PVA molecules there are two chemical structure, that is 1,3 and 1,2 glycol structure, but the main structure of 1,3 glycol structure, that is, "hang themselves" structure. The degree of polymerization of polyethylene into high degree of polymerization (molecular weight of 25 to 30 million), a high degree of polymerization (molecular weight of 17-22 million), the degree of polymerization (molecular weight of 12 to 15 million) and oligomeric custom [2.5] ~ 35000. Alcohol Solutions typically 78%, 88%, 98% three. Some alcohol solution of soluble starch is usually 87% to 89% of them, alcoholysis of soluble starch for 98% ~ 100%. Regular admission average degree of polymerization of 1000, 100 on the median in front of the alcoholysis percentage placed at the back, such as those in Table 17-88 degree of polymerization of 700 l, the solubility of 88%. In general, increased degree of polymerization, solution viscosity increases, the film strength and solvent-resistance increased, the water solubility, film dropped after elongation. The relative density of polyvinyl alcohol (25 ° C / 4 ° C) 1.27 ~ 1.31 (solid), 1.02 (10% solution), the melting point of 230 ° C and glass transition temperature of 75 to 85 ° C in air heated to 100 ° C over slow slow change color, embrittlement. Heating to 160 ~ 170 ° C dehydration ether, lost solubility, heated to 200 ° C begin to decompose. More than 250 ° C into containing conjugated double bond polymers. A refractive index. 49 ~ 1. 52, the thermal conductivity 0.2w / (K m), a heat capacity ~ 5J / (kg K), resistivity (3.1 ~ 3. 8) × 107 ohm cm. Dissolved in water, in order to completely dissolve the normal heating to 65 ° C ~ 75. Do not dissolve in gasoline, kerosene, vegetable oil, benzene, toluene, 1,2-dichloroethane, carbon tetrachloride, acetone, ethyl acetate, methanol, ethylene glycol, etc.. DMSO-soluble. L50 120 ° C ~ soluble glycerol. But the cold to become gelatin at room temperature. PVA solution should first be added to the mixing room temperature water. Uniformly dispersed after warming accelerates the dissolution, which would prevent caking and affect dissolution rate. PVA aqueous solution (5%) of borax and boric acid are very sensitive, it can lead to gel, when borax solution to the quality of 1%, it will have irreversible coagulation amination. Chromate, dichromated, Permanganate also enable PVA gel. L 7-88 PVA aqueous solution at room temperature with time viscosity is gradually increasing. But the concentration of 8% when the viscosity is absolutely stable, and has nothing to do with time, the special session of the phenomenon c PVA film is good, except steam and ammonia gas than many a high degree of discomfort gas. Light, good illumination from impact. Qualcomm fire can burn, a special smell. The storage solution, and sometimes there will be change drugs. Non-toxic to human skin irritation.
for polyvinyl acetate emulsion polymerization stabilizer. Used in the manufacture of water-soluble adhesive. Starch adhesives used modifier. Preparation can be used for emulsion and solvent benzene-resistant sealant. Also used as a release agent, decentralized agents. Store in a cool, dry coffers. Moisture, fire.
PVA called PVA l 17-92 7-92, white granules or powder form. Soluble in water, dissolved temperature 75 to 80 ° C Other basic properties and PVA17-88 the same. Emulsion polymerization for the stabilizer. Used in the manufacture of water-soluble adhesive. Store in a cool, dry coffers, fire, moisture, also known as the 17-99
Sizing PVA resin (Sizing resin), or PVAl7-99. A white or slightly yellow powder or floc solid. Glass transition temperature 85 ° C, saponification value 12mgKOH 3 ~ / g. Soluble 90 ~ 95 ° C water, almost insoluble in cold water. Concentrations greater than l0% of the aqueous solution at room temperature will gel into a cold, heat becomes thinner restore mobility. For viscosity stability in solution by adding an appropriate amount of sodium thiocyanate, thiocyanate calcium, phenol, alcohol, etc. viscosity stabilizer. PvAl7-99 solution on the commission caused sand than PvAl7 gel. 88 more sensitive, solution quality of the 0.1% borax would make 5% PVAl7-99 aqueous gel, which leads to the same concentration of PVA Gel 17-88 solution of borax 1% of the volume required. For the same concentration, the same alcohol solution of aqueous polyvinyl alcohol and borax occurred more than boric acid gel. PVAl7-99 than PVAl7-88 benzene, chlorinated hydrocarbons, esters, ketones, ethers, hydrocarbon solvents such as greater tolerance. Heat to 100 ° C above gradually change color at 150 ° C and above will soon change, when more than 200 ° C to decomposition. PVA heating can change the nature by adding 0.5% to 3% of boric acid and be curtailed. Light, good light from the impact. With the long chain of polyols esterification, ethers, such as acetal chemical reactivity. Qualcomm fire will burn, a special smell. Non-toxic to human skin irritation.
PVA 17-99B mainly used in the manufacture of high viscosity polyvinyl butyral. The extensive use of the scattered material sizing agents. Other types of 17-99 for polyvinyl acetate emulsion polymerization stabilizing agent, but the results are not 17-88, the general is to l7 - 99 and 17-88 mix. 17-99 used in the manufacture of polyvinyl formaldehyde solution (07 l is the main construction adhesive). 17-99 also prepared for the solvent benzene-resistant sealant. Store in a cool, dry coffers, moisture, fire.
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More Detailed Data:
1) polyvinyl alcohol;PVA
2) Polyvinyl alcohol;PVA
3) poly(vinyl alcohol);PVA
4) polyvinyl alcohol
5) PVA
6) polyvinylacetate;PVA;PVAC
7) polyvinyl alcohol for medical use
8) Polyvinyl Alcohol Eye Drops
9) Vanillin;4-Hydroxy-3-methoxybenzaldehyde;Methylprotocatechuic aldehyde;Va
10) PVAc;Po1yvinyl acetate emulsion
Notice Some description was translated by software and the data is only as a reference.
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