微波法制备O-羟丙基-N-辛基壳聚糖及其性能表征

通过微波法,由壳聚糖与环氧丙烷反应制备O-羟丙基壳聚糖(HPCS),然后在相转移催化剂四丁基溴化铵作用下与溴化辛烷反应制备成O-羟丙基-N-辛基壳聚糖(C₈-HPCS)。 中间产物HPCS与目标产物C₈-HPCS的结构通过FTIR及¹H NMR等技术手段分析得到验证。 实验结果表明,当反应时间为50 min,温度为65 ℃,溴代辛烷用量8 mL,四丁基溴化铵用量0.07 g时,制备所得的C₈-HPCS具有较好的综合性能:起泡性为3.9 cm,稳泡性为88.9%,乳化性为78.1%。 C₈-HPCS的临界胶束浓度(CMC)为0.015 g/L,表面张力约为58.5 mN/m;亲水亲油平衡值(HLB)测定结果为13.44。 同步热分析表明C₈-HPCS在270 ℃之前均是稳定的;X射线衍射图谱表明改性后的C₈-HPCS为非晶体结构。

Microwave Synthesis and Characterization of O-Hydroxypropyl-N-octyl Chitosan

O-hydroxypropyl-N-octyl chitosan(C₈-HPCS) was prepared by reacting 1-octyl bromide with O-hydroxypropyl chitosan(HPCS) under microwave heating. HPCS was prepared with chitosan and propylene oxide in presence of phase transfer catalyst tetrabutylammonium bromide. The intermediate HPCS and the objective product C₈-HPCS were characterized by FTIR and ¹H NMR spectroscopy. The results show that C₈-HPCS has an excellent integrated performance when the reaction time is 50 min, the temperature is 65 ℃, the dosage of bromooctane is 8 mL and the dosage of tetrabutylammonium bromide is 0.07 g. The foamability, foaming property and emulsibility are 3.9 cm, 88.9% and 78.1%, respectively. The critical micelle concentration of C₈-HPCS is 0.015 g/L with the surface tension of 58.5 mN/m and the hydrophile lipophile balance number is 13.44. The thermal stability analysis shows that the C₈-HPCS is stable up to 270 ℃ and the XRD analysis indicates that the quaternized chitosan is completely amorphous.