| 摘要 |
PURPOSE: A saponification method of polyacetic acid vinyl and micro spherical granular poly(vinyl alcohol) prepared by the method are provided, to prepare poly(vinyl alcohol) from acetic acid vinyl directly without separation and drying, thereby allowing the continuous process to be carried out. CONSTITUTION: The saponification method comprises the steps of adding polyacetic acid vinyl prepared by suspension polymerization to the mixture comprising 0.01-0.1 mol of methanol, 0.01-0.15 mol of a salt selected from the group consisting of NaOH, KOH, Ca(OH)2 and LiOH, 0.01-0.1 mol of a salt selected from the group consisting of sodium sulfate, sodium sulfite, sodium chloride, calcium sulfate and magnesium sulfate, and 1.0-2.5 mol of H2O based on 1 g of polyacetic acid vinyl particle, without the purification, separation and drying of polyacetic acid vinyl; and saponifying it at 0-90 deg.C. The prepared micro spherical granular poly(vinyl alcohol) has a core/shell dual structure comprising a polyacetic acid vinyl core and a shell whose degree of saponification of polyacetic acid vinyl is 20-99.9%.
|
