CHEMICAL MODIFICATION OF BIOPOLYMERS MECHANISM OF MODEL   GRAFT-COPOLYMERIZATION OF CHITOSAN

CORC > 北京大学 > 化学与分子工程学院

	CHEMICAL MODIFICATION OF BIOPOLYMERS MECHANISM OF MODEL GRAFT-COPOLYMERIZATION OF CHITOSAN
	LI, W ; LI, ZY ; LIAO, WS ; FENG, XD
刊名	journal of biomaterials science polymer edition
	1993
关键词	GRAFT COPOLYMERIZATION CHITOSAN MODEL/CE(IV) ADJACENT HYDROXYLAMINE/CE(IV) CE(IV) INITIATION REACTION MECHANISM
英文摘要	Mechanism of graft copolymerization of vinyl monomers onto chitosan initiated by Ce(IV) ion, one of the important ways of chemical modification of chitosan, has been investigated by means of kinetics measurement and polymer chain structure analysis. It is found that when Ce(IV) ions reacts with adjacent hydroxylamine structure in chitosan, a chelate complex is first formed and then it disproportionates to radical for initiation of graft copolymerization. There exist two ways for such initiation depending upon the reaction temperature. For a reaction temperature lower than 40-degrees-C, a -CHO group and a -C=NH group are introduced, and the aldehyde group reacts with Ce(IV) ions to form an acyl radical which initiates a graft polymer chain in this saccharide unit. For temperatures higher than 90-degrees-C, the -C=NH group hydrolyzes to form an amine and an aldehyde group which also reacts with Ce(IV) ions. In this case there should be two aldehyde groups, i.e. two initiation sites, in one adjacent hydroxyl-amine structure. That means that the initial radical in the chitosan/Ce(IV) system is similar to that in the cellulose/Ce(IV) one, but the former usually gives a lower grafting reactivity than the latter due to the higher stability of the chelate.; Engineering, Biomedical; Materials Science, Biomaterials; Polymer Science; SCI(E); PubMed; 13; ARTICLE; 5; 557-566; 4
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/312644]
专题	化学与分子工程学院
推荐引用方式 GB/T 7714	LI, W,LI, ZY,LIAO, WS,et al. CHEMICAL MODIFICATION OF BIOPOLYMERS MECHANISM OF MODEL GRAFT-COPOLYMERIZATION OF CHITOSAN[J]. journal of biomaterials science polymer edition,1993.
APA	LI, W,LI, ZY,LIAO, WS,&FENG, XD.(1993).CHEMICAL MODIFICATION OF BIOPOLYMERS MECHANISM OF MODEL GRAFT-COPOLYMERIZATION OF CHITOSAN.journal of biomaterials science polymer edition.
MLA	LI, W,et al."CHEMICAL MODIFICATION OF BIOPOLYMERS MECHANISM OF MODEL GRAFT-COPOLYMERIZATION OF CHITOSAN".journal of biomaterials science polymer edition (1993).