Study On Poly (L-lactide) Modified With β-CD

Separately useβ-cyclodextrin (β-CD) react with the L-lactide (LLA) directly to synthesisgraft copolymer and use chloride acylatingβ-CD react with LLA to synthesis graft copolymer,in order to research the modification ofβ-CD to polylactide.First, take DMF as the solvent, under the 80℃temperature and nitrogen environment, joinsβ-CD and LLA according to certainproportion, to prepareβ-CD/POly(LLA) graft copolymer,determine its hydrophilicyty performance. The graft copolymers were characterized by meansof FTIR and ¹H-NMR. The result indicated that, used this method can synthesisβ-CD/poly-(LLA) graft copolymer, also the hydrophilicyty performance enhanced along with the contentproportion ofβ-CD increase.In order to avoid the water affinity hydroxyl ofβ-CD be completely destroyed, we synthesischloride acylatingβ-CD, to turn the partial hydroxyl to acetyl chloride acetylating, and thenreact with LLA to synthesis graft copolymer. In the process of synthesis chloride acylatingβ-CD,we studied the influence of react condition to the production rate and acylation ratio ofthe chloride acylatingβ-CD,also we discussed at which position ofβ-CD the chloroacylationoccur, and calculated the acylation ratio.The result indicated that, under 80℃temperatures react12h the yield ratio of chloride acylatingβ-CD is highest,chloride acylatingβ-CD with differentacylation ratio can be synthesized rely on the content of chloroacety chloride agent used, thechloroacylation occur at the hydroxyl of C-2 and C-6 ofβ-CD.Syhnthesis the graft copolymers use the chloride acylatingβ-CD react with LLA, the graftcopolymers were characterized by means ¹H-NMR, ¹³C-NMR, XRD and DSC,calculated thegraft ratio of the graft copolymer, also we studied the influence of grafting rate to the waterabsorptivity and the degeneration performance of the graft copolymers, in order to furtherimprove the hydrophilicyty of the graft copolymers,we turn the graft copolymer into quaternryammonium salt.The result indicated that, the graft rate of the graft copolymers areapproximately equal to the acylation ratio of the chloride acylatingβ-CD, the graft reaction takeplace on the position of C-3 ofβ-CD; the graft polymer melting point to reduce along with thegraft rate of the graft copolymer increase, but its water absorptivity and the degeneration rate strengthens along with the graft rate of the graft copolymers increase, when turn to quaternryammonium salt just the water-absorptivity improved,not the degeneration.Therefore we may regulate the graft rate of the graft copolym er through change the acylationratio of the chloride acylatingβ-CD, then regulation the graft polymers performance, make thequaterm'y ammonium salt into chloride acylatingβ-CD can not only protect the water affinityhydroxyl, but also can contribute to the water-absorptivity, and make a new way in the field ofmodifying PLA.