Effect and mechanism of polyvinyl alcohol powder in putty

After the polyvinyl alcohol powder is dry mixed with other powders, water is added to form a paste slurry. After the water evaporates, it forms a frame structure composed of inorganic and organic binders, that is, a brittle and hard skeleton composed of hydraulic materials, and the flexible connection of polyvinyl alcohol powder in the void and the film-forming structure of the solid surface. Many tiny little springs are attached to the rigid frame.

       Because the tensile strength of the polymer resin film composed of polyvinyl alcohol is much higher than that of the hydraulic material, the strength of the putty itself can be enhanced, that is, the cohesive force can be improved. Because of the flexibility of the polymer, the deformation capacity is much higher than that of the rigid structure composed of hydraulic materials, so the deformation capacity of the putty can be improved, the effect of stress relaxation has been greatly improved, and the crack resistance of the putty can be improved.

       The water resistance of polyvinyl alcohol powder is weaker than that of redispersible latex powder, but in the alkaline system of water-resistant putty rich in cement, polyvinyl alcohol will be saponified by the alkali generated by the hydration of cement in the putty, and it will be saponified by quartz. The hydrophilic function of polyvinyl alcohol is greatly weakened by the absorption of the material, so it will not affect the water-resistant performance of the water-resistant putty.