Based on degree of polymerizationThe higher degree of polymerization of polymer is,the higher viscosity of solution and adhesion strength

of film are.The higher degree of polymerization of polymer is,the less water solubility and the higher solvent resist-

ance are.The higher the degree of polymerization of polymer is,the higher tensile strength of PVA film is.The higher the degree of polymerization of polymer is,the less penetration and softness of film is.The higher the degree of polymerization of polymer is,the better protective ability is