邻苯二甲酰化壳聚糖的合成与溶致液晶表征

Room Temperature Synthesis and Lyotropic Liquid Crystalline Characterization of Phthaloyl Chitosan

从全脱乙酰化壳聚糖出发,在室温下合成了一系列不同取代度的邻苯二甲酰化壳聚糖(PhCS),由于反应条件温和,产物未发生进一步的酰亚胺化.X射线电子能谱(XPS)被用来测定PhCS的取代度.测定结果表明在N上和O上均发生取代,N上反应的取代度随酸酐用量的增加基本保持不变(0.26±0.03),而O上的取代度却不断变大(0.01～1.54),合成产物的总取代度为0.26～1.81.邻苯二甲酰化壳聚糖可溶解于普通的有机溶剂,如DMSO、二氯乙酸和甲酸,并形成溶致液晶.测定了PhCS在这些溶剂中的临界浓度(c),结果表明c基本上不受取代度变化的影响.

Phthaloyl chitosan,an important chitosan derivative,has been used in many fields especially as an intermediate for further modification of chitosan.Several samples with different degree of substitution were synthesized from completely deacetylated chitosan at room temperature.Only amic acid chitosans were found in these product instead of both amic acid chitosan and imide chitosan that were found at rigorous high temperature (more than 130 ℃) as reported by others.XPS was used to measure the degree of substitution.From the measurement,it was shown that the substitution happened at either N atom or O atom of the glucosamine units.As the dosage of phthaloyl anhydride changed,degree of substitution on N atom (dsN) remained almost unchange (0.26±0.03) while degree of substitution on O atom (dsO) varied from 0.01 to 1.54.PhCS can dissolve in several common organic solvents such as DMSO,dichloroacetic acid (DCA),formic acid (FA) etc and forms lyotropic mesophases.Their critical concentrations (c) were determined in some of the above solutions.The dsO showed only slight effects on c.The results were consistent with previous studies on other systems of chitosan derivatives.