ポリアクリロニトリル共重合体の湿式凝固におけるゲル構造形成過程
1995 年 51 巻 8 号 p. 383-390
詳細
1995 年 51 巻 8 号 p. 383-390
Acrylonitrile (AN)/Methylacrylate (MA) copolymer (AN/MA=90/10 wt%, Mw=15.9×104) solutions dissolved in 58 wt% aqueous NaSCN were coagulated in a dilute aqueous NaSCN using the film coagulation method and changes of properties of gel with the time in coagulation were investigated.
In the process of coagulation, the composition of gel changed continuously. The polymer precipitated and coagulation completed when a percentage of NaSCN in gel decreased to 25-30 wt%.
Until a percentage of NaSCN in gel decreased to 25-30 wt%, a percentage of polymer in gel was constant and was almost same as that in the polymer solutions. Inter-diffusion between NaSCN and coagulant (water) occurred. The amount of NaSCN diffused out of gel and coagulant diffused into gel were equal.
When a percentage of NaSCN in gel decreased below 25 wt%, diffusion of coagulant into gel became almost zero and one-way diffusion of NaSCN and water out of gel occurred, then a percentage of polymer in gel began to increase and gel began to contract.
