用超临界二氧化碳法制备超强吸水剂

Preparation of superabsorbent polymer in supercritical carbon dioxide

以N,N′-亚甲基双丙烯酰胺(BIS)为交联剂,研究了疏水性单体丙烯酸十八酯(OA)与亲水性单体丙烯酸(AA)在超临界二氧化碳中的聚合反应,制备了超强吸水剂。结果表明,65℃、压力大于13MPa时,制备的产物都为白色固体粉末。用超临界二氧化碳萃取技术可以对产物进行纯化,50℃、20MPa下,产物经超临界二氧化碳萃取2次后纯度可大于95%,4次后单体残留率为0 28%。该超强吸水剂的吸水率有一定下降,然而保水率却得到提高。

Superabsorbent polymer was synthesized by co-polymerization of acrylic acid and octadecyl acrylate in supercritical carbon dioxide using N,N′-methylene-bis-acrylamide as crosslinking agent.The results indicated that under 65 ℃ and 13 MPa the product was white solid powder.The purification of the product was carried out by supercritical carbon dioxide extraction.Under 20 MPa and 50 ℃,the purity of the product can be higher than 95 % after 2 times extraction.The content of residual monomer is 0.28 % after 4 times extraction.The water absorbency of such superabsorbent polymer is some what lowered,but higher water-retention capability is improved.