Chemical Modification Of Polysaccharides Via Grafting Poly(1,4-dioxan-2-one)

Poly(1,4-dioxan-2-one) or poly (p-dioxanone), PPDO, is a well-known aliphatic polyester having good physical properties and bio-compatibility, and has been used to make monofilament sutures with good tenacity and knotting. Recently, its uses in the field of drug delivery system have been reported more and more, while the poor compatibility with drug and poor stability in body limit its uses.Natural polymers (such as starch and chitosan) and its derivatives are known to be nontoxic, abundant and biocompatible in animal tissues, as well as fully biodegradable. Much attention has been paid to its biomedical, ecological, and industrial application in past decades. In order to improve the properties of both of PPDO and natural polymers, a possible way is to copolymerize the PPDO with other biological materials such as starch, chitosan and their derivatives.In this paper, we focus on a new way to synthesis PPDO/starh(chitosan) graft copolymers. By using the active group of TDI, NCO groups, to react with hydroxyl groups at the terminal of the PPDO and in the natural polymers, respectively, the PPDO with certain chain lengths are introduced onto the backbone of natural polymer. The effect of feed ratio, reaction time and temperature on the polymerization was studied.The structures and properties of graft copolymers were investigated by FT-IR, 1H-NMR, differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), wide-angle-X-ray diffractometry (WAXD). And their biodegradability and applications in drug delivery were also investigated.