Views: 266 Author: Site Editor Publish Time: 2023-07-17 Origin: Site
Polyvinyl alcohol (PVA) is made from vinyl acetate by polymerisation reaction and alcoholysis, it is a white, stable, non-toxic water-soluble polymer, it can be quickly dissolved in water to form a stable colloid, water is a good solvent.
Polyvinyl alcohol resin (PVA) aqueous solution has good film-forming and emulsifying properties. The film formed has excellent adhesion, solvent resistance, friction resistance, tensile strength and oxygen barrier. Polyvinyl alcohol resin (PVA) has both hydrophilic and hydrophobic functional groups, so it is a material with interfacial activity, so it can be used as a protective colloid for polymer emulsification and suspension polymerisation.
Polyvinyl alcohol resin (PVA) is mainly used in the production of synthetic fibres, plastics, adhesives, coatings, new building materials and other products, and is widely used in the chemical industry, textile, printing and paper making, tanning industry, construction and other industries and fields.
Chemical name: Polyvinyl alcohol
Ⅱ. The molecular composition and structure: (CH3CHCOOCH3) x (CH2CHOH) y
Where: x + y indicates the degree of polymerisation, y / (x + y) indicates the degree of alcoholysis
Ⅲ. Physical and chemical properties
A. Solubility: polyvinyl alcohol powder can be dissolved in water. Polyvinyl alcohol resin (PVA) with alcoholysis degree less than 95% can be dissolved in water at room temperature, and polyvinyl alcohol resin (PVA) with alcoholysis degree more than 99.5% can only be dissolved in hot water above 95℃.
B, thermal stability: polyvinyl alcohol will soften when heated, there is no significant change below 40 ° C, 160 ° C or more, prolonged heating will be gradually coloured, 220 ° C or more decomposition occurs, generating water, acetic acid, acetaldehyde and butenal.
C, chemical resistance: PVA is almost unaffected by weak acids, weak bases or organic solvents, high oil resistance.
D, storage stability: PVA is a low-viscosity polymer, its aqueous solution at room temperature is very stable. The aqueous solution will not deteriorate during storage.
E, film-forming properties: due to the high adhesion between the PVA molecules, PVA is easy to form a film, the formation of the film is colourless and transparent, with good mechanical strength, smooth surface and not sticky, good solubility. The molecular film has good light transmittance, high moisture permeability, non-electricity, non-absorbent dust, and good printability.
PVA can be regarded as a linear polymer with secondary hydroxyl groups. The hydroxyl group in the molecule has high activity and can carry out typical chemical reactions of low alcohols, such as esterification, etherification, acetalisation, etc. It can also react with many inorganic or organic compounds.
Ⅳ. Packaging, transport and storage.
Product appearance: flocculent, flaky, powdery.
A. 12.5kg, 20kg, 25kg plastic woven bag or paper bag, 750Kg~1000Kg plastic woven tonne bag.
B. When transporting, use clean means of transport to prevent moisture, rain and sunshine, and hold it gently to prevent scratching or breaking the package.
C. Store in dry, well-ventilated room, room temperature 5-30℃. Do not close to the heat source, prevent moisture, avoid sun exposure. It is strictly prohibited to store together with volatile chemicals to prevent adsorption and deterioration.
D. This product is non-dangerous, non-explosive, non-oxidising, non-corrosive, non-radioactive, non-toxic and harmful.