铈盐引发聚醚氨酯膜上丙烯酰胺接枝聚合反应

由聚四亚甲基醚二醇、4,4′-二苯基甲烷二异氰酸酯与乙二胺或丁二醇扩链剂合成的聚醚氨酯薄膜,可顺利地在室温下用硝酸铈铵引发接枝丙烯酰胺共聚合反应,这可以从反应后的薄膜由起始时是透明的而变为不透明,也可以从接枝后的薄膜比基膜有较大的吸水率,以及从扫描电子显微镜观察到薄膜表面上有凸起图象的高分子链所证实,由于先发生接枝共聚合而后才是均聚反应,因而保证了接枝后的薄膜几乎不附着聚丙烯酰胺。

GRAFTING POLYMERIZATION OF ACRYLAMIDE ON POLYETHER URETHANE FILM INITIATED BY CERIC SALT

Grafting polymerization of acrylamide (AAM) onto polyether urethane (PEU) was investigated in aqueous solution by using eerie ammonium nitrate (CAN) as-initiator. The grafted polymers were synthesized as follows: (i) a variety of PBU from poly (oxytetramethylene) glycol (PTMG), 4,4'-diphenylmethane diisocyanate (MDI), and ethyleneamine (E) or butandiol (B) as extender under different reaction conditions were used to cast into films; (ii) grafting of PAAM onto PEU film by using CAN and (iii) the grafted PEU substrate was then extracted with boiling distilled water, to remove the residues of AAM and PAAM homopolymer. The PEU films of varying thicknesses with either B or E as extender could be easily grafted by AAM. The grafting polymerization was verified from the fact that the grafted substrates become opaque and possessing higher percentage of water absorption than the original one, and from the scanning electron microscopy photographs with salient micrograph showing grafts of macrochain on the surface of film, In addition, the factors that influence the grafting copolymerization were studied, and the mechanism of grafting polymerization has been proposed.