PVA, also known as polyvinyl alcohol, PVOH, cas 9002-89-5, is a solid that can be in the form of white powder, flakes or flocculent. The glass transition temperature is 60 to 85°C. Polyvinyl alcohol contains many alcohol groups, is polar, and can form hydrogen bonds with water, so it can be soluble in polar water. Polyvinyl alcohol can also be soluble in hot hydroxyl-containing solvents such as glycerol, phenol, etc., insoluble in methanol, benzene, acetone, gasoline and other general organic solvents.
According to the degree of polymerization can be divided into ultra-high polymerization (molecular weight 25 ~ 300,000), high polymerization (molecular weight 17 ~ 220,000), medium polymerization (molecular weight 12 ~ 150,000) and low polymerization (molecular weight 2.5 ~ 35,000). The degree of alcoholysis generally has a complete alcoholysis (alcoholysis 98 ~ 100%), partial alcoholysis (alcoholysis 87 ~ 89%) and alcoholysis 78% three kinds. Product grades will generally be polymerization degree of thousands, hundreds of digits in the front, the degree of alcoholysis in the back, for example, polyvinyl alcohol 17-99 that polymerization degree of 1.7k, the degree of alcoholysis for 99%.
Polyvinyl alcohol (PVA) is a widely used water-soluble polymer, PVA can quickly dissolve in water to form a stable colloid, between the performance of plastics and rubber, in addition to fiber raw materials, but also used in the production of a large number of coatings, adhesives, paper processing agents, emulsifiers, dispersants, films and other products, applications throughout the textile,food,medicine, construction,wood processing,paper,printing,agriculture, steel, polymer chemical industry.
PVA polymer powder is particularly suitable for use as an additive in construction mortar, and can improve the flexibility, water retention and mortar adhesion of cement mortar when used in conjunction with water retention agents of methyl cellulose ether. It can reduce the friction of mortar, thus enhancing the working efficiency as well as quality.
In addition, polyvinyl alcohol biodegradable has been the main direction of human research in recent years.
