The gained product was dried under vacuum
(70◦C) for 2 days. Epoxy chloropropane (50 g, 0.540 mol)
was added to the dried product above and sodium hydroxide
(0.25 g, 0.006 mol) was added every half hour (14
times) at 55◦C. Then the mixture was heated to 60◦C with
stirring, and this temperature was maintained for 6 h and
the excess of epoxy chloropropane was distilled off under
reduced pressure. The reaction mixture was cooled and
then dissolved in benzene (40 ml). The resulting sodium
chloride was removed by filtration with a glass filter,
and then benzene was distilled. The clear liquid product
was dried under vacuum (50◦C) for 2 days. The yield of
polymer was above 91.3%.