Polyvinyl alcohol is an important polymer. The structure is given...

PVA is prepared by hydrolysis of polyvinyl acetate. Other vinyl ester-derived polymers are sometimes used, with formate, chloroacetate groups instead of acetate. The conversion of the polyesters is usually conducted by base-catalysed transesterification with ethanol:
${\left[C{H}_{2}CH\left(OAc\right)\right]}_{n} + {C}_{2}{H}_{5}OH \to {\left[C{H}_{2}CH\left(OH\right)\right]}_{n} + {C}_{2}{H}_{5}OAc$