Industrial Grade PVA

Описание

Industrial Grade PVA, the full name of which is polyvinyl alcohol, is a water-soluble polymer with properties between plastic and rubber. PVA usually exists in the form of white flakes, flocs or powder solids and is odorless. It is a widely used material with good solubility and plasticity, and can be formed by processes such as heating and pressing. The molecular structure of PVA contains a large number of hydroxyl groups (-OH), which makes it highly active and capable of undergoing a variety of chemical reactions.

Physical properties:

Solubility and viscosity:

polyvinyl alcohol, is a colorless and odorless solid that can be dissolv in water and has a high viscosity. When PVA aqueous solution is added to cement. Its viscosity helps to improve the fluidity and stability of cement slurry, so that cement can be better mix and evenly mixed during stirring, reducing stratification and segregation.

Ement, it can give cement-base materials a certain degree of flexibility. So that when subjected to external forces, it will not easily produce brittle fractures like ordinary cement. But has a certain deformation ability to buffer external forces.

Chemical properties

Reactivity: PVA can react with many organic and inorganic substances. In the cement system, However it can react chemically with cement hydration products to form a more stable structure and enhance the bonding force inside the cement matrix.

Chemical corrosion resistance: PVA has good chemical corrosion resistance. Which makes cement with polyvinyl alcohol,

added better resist chemical erosion in some environments with chemical corrosion risks, such as soil or water containing acid and alkali substances, and prolong the service life of cement structures.

Uses of PVA in cement:

Improve mechanical properties: Enhance toughness and ductility: The modified polyvinyl alcohol, fiber has excellent mechanical properties, and the tensile strength of high-strength and high-modulus PVA fiber can reach 1500MPa. Which is equivalent to the tensile strength of low-carbon steel fiber. Adding it to cement can effectively improve the ductility and toughness of cement-based materials. And reduce the generation and expansion of cracks. For example, in my country’s construction engineering practice, adding 1kg of high-strength. Then high-modulus PVA fiber to each cubic meter of concrete effectively solves the shrinkage crack problem caused by early shrinkage of concrete.

Improve flexural, shear and impact resistance: PVA fiber can effectively improve the flexural strength, shear strength and impact resistance of cement-based materials. When subjected to external impact or bending, the fiber can disperse stress. Avoid stress concentration and cause material damage, and make the cement structure more durable2.

Improve durability: Reduce shrinkage cracking: Traditional cement-based materials are prone to shrinkage cracking during the hardening process. And then the addition of polyvinyl alcohol,

can effectively reduce this shrinkage cracking. PVA fiber forms a three-dimensional mesh structure in the cement matrix. Which limits the movement and shrinkage of cement particles, thereby reducing the probability of shrinkage cracks.

Reduce permeability: PVA fiber reinforce

cement-based materials can effectively reduce the permeability of the material. The fiber fills the pores and microcracks in the cement matrix, preventing the intrusion of moisture and harmful media. Improving the impermeability and frost resistance of the cement structure, and extending its service life.

Other uses：
Improve adhesion: PVA has good adhesion. Using it in cement can enhance the adhesion between cement and other materials (such as masonry, steel bars, etc.). Making the entire building structure more stable.

Improve construction performance: The viscosity of PVA can improve the construction performance of cement slurry. Making it easier to apply, pump and vibrate, improving construction efficiency and quality