十一种壳聚糖衍生物的紫外吸收特性

十一种壳聚糖衍生物的紫外吸收特性;壳聚糖;胆甾液晶;紫外光吸收剂;化妆品

UV-Absorption Characteristics of Eleven Chitosan Derivatives

The UV absorption spectra of eleven chitosan derivatives,for example O-cyanoethyl chitosan and(N-benzyl) chitosan,were obtained.In dilute solution,the UV-Vis absorption spectra of all these(derivatives) cover the ultraviolet B region(280~320 nm).The UV-Vis spectra of N-salicylaldehyde modified chitosan and N-cinnamaldehyde modified chitosan cover part of the ultraviolet A region(>320 nm).In concentrated(solution),complete spectra cannot be achieved due to the limit of the instrument.With the increase of the(concentration),red shift appears in the UV-Vis spectra,which indicates that the state of(aggregation) has changed.At the critical concentration for the cholesteric liquid crystalline phase,the position of the peak shifts obviously.This phenomenon can be explained by the increase of the interaction of the chromophore(induced) by the ordered arrangement of the mesophase.Moreover the UV-Vis spectrum of the film of N-benzyl chitosan in(liquid) crystalline state covers the whole ultraviolet region.The UV-absorption characteristics of these chitosan derivatives show that they may be used as photoprotectants employed in cosmetic and pharmaceutical preparations.