Name: Polyvinyl Alcohol
Abbreviation: PVA
Polyvinyl alcohol (PVA) is a white, stable, and non-toxic water-soluble polymer made by polymerization and alcoholysis of vinyl acetate. It is a powder, flake, or flocculent solid.
Polyvinyl alcohol contains many alcohol groups, is polar, and can form hydrogen bonds with water, making it soluble in polar water; It is also soluble in hot hydroxyl containing solvents such as glycerol, phenol, etc., but insoluble in general organic solvents such as methanol, benzene, acetone, gasoline, etc.
one
Physical and chemical properties
1、 Physical properties
A. Solubility: Polyvinyl alcohol powder can dissolve in water. Polyvinyl alcohol Resin (PVA) with an alcoholysis degree less than 95% can be dissolved in room temperature water, while polyvinyl alcohol resin (PVA) with an alcoholysis degree greater than 99.5% can only be dissolved in hot water above 95 ℃.
B. Thermal stability: Polyvinyl alcohol softens when heated and does not show significant changes below 40 ℃. Glass transition temperature: 75-85 ℃. When heated above 100 ℃, it gradually changes color and becomes brittle. Above 160 ℃, prolonged heating will gradually color, dehydrate and etherify, and lose solubility; At temperatures above 220 ℃, decomposition occurs, producing water, Acetic Acid, acetaldehyde, and butenal; Transforming into a polymer containing conjugated double bonds at temperatures exceeding 250 ℃.
C. Chemical resistance: PVA is almost unaffected by weak acids, bases, or organic solvents, and has high oil resistance.
D. Storage stability: PVA is a low viscosity polymer, and its aqueous solution is very stable at room temperature. The aqueous solution will not deteriorate during storage.
E. Film forming property: Due to the high adhesion between PVA molecules, PVA is easy to form a film, resulting in a colorless and transparent film with good mechanical strength, a smooth surface without sticking, and good solubility. Molecular membranes have good light transmittance, high moisture permeability, no charge, no dust absorption, and good printability.
2、 Chemical properties
PVA can be regarded as a linear polymer with secondary hydroxyl groups. The hydroxyl groups in molecules have high activity and can undergo typical chemical reactions of low alcohols, such as esterification, etherification, acetalization, etc. They can also react with many inorganic or organic compounds.
two
Packaging, transportation, and storage:
Product appearance: white flocculent , flaky , and powdery solid. This product is non hazardous, non explosive, non oxidizing, non corrosive, non radioactive, and non toxic and harmful.
1. Packaging
Packaging in 12.5kg, 20kg, 25kg plastic woven bags or paper bags, 750kg to 1000kg plastic woven ton bags.
2. Transportation
Use clean transportation tools to prevent moisture, rain, and sun damage. Handle with care during transportation to prevent scratches or falls on the packaging.
3. Storage
In a dry and well ventilated indoor environment, the room temperature is 5-30 ℃. Please do not approach heat sources, strictly prevent moisture, and avoid direct sunlight. It is strictly prohibited to store together with volatile chemicals to prevent adsorption and deterioration.
three
Product application
Polyvinyl alcohol resin (PVA) aqueous solution has good film-forming and emulsifying properties. It can serve as a protective colloid for polymer emulsification and suspension polymerization reactions.
Polyvinyl alcohol can be used in textile pulp, Vinyl fiber, paper coating agents, building materials, adhesives, PVA films , PVB raw materials , food and medicine, and other fields. PVA can also be used as a soil amendment, polymerization suspension agent and emulsifier, quenching agent, and so on. In addition, with the continuous development and improvement of PVA performance, its applications are constantly expanding.
Various types and uses of polyvinyl alcohol (PVA)
1. Vinylon raw materials:
Polyvinyl alcohol can be dissolved, spun, and then subjected to acetalization treatment to produce vinylon fibers. It can be mixed with cotton, wool, viscose fibers, etc. to produce vinylon textiles, which are widely used in clothing, tarpaulins, curtain cords, fish net ropes, etc. Generally, it is better to choose PVA 17-99 as the spinning material with an average polymerization degree of 1750 ± 50
2. Warp sizing:
a. A sizing material mainly composed of polyvinyl alcohol has good adhesion to cotton, linen, polyester, and vinylon viscose fibers. After film formation, it is smooth and sturdy, wear-resistant, and promotes the weaving suitability of warp yarns, reducing friction and bending caused by warp yarns during the weaving process. Intense movements such as stretching cause warp breakage, reducing the breakage rate of the fabric machine. Moreover, the woven fabric has a firm texture. Smooth and delicate, the fabric surface is not rough.
b. Polyvinyl alcohol is a water-soluble polymer compound that is easy to mix, apply, and remove. It is generally better to choose polyvinyl alcohol (such as PVA 15-99 , PVA 16-99 , PVA 17-99 ) with lower average polymerization degree as the slurry.
3. Adhesive:
a. The aqueous solution of
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