纳米甲壳素的快速制备及其乳化性能研究

Rapid preparation of nano-chitin for stabilizing Pickering emulsions

简化磷酸溶解再生制备纳米甲壳素的工艺,避免大量溶剂的使用、缩短制备时间以及提高产率。采用X射线衍射、透射电镜和电感耦合等离子体发射光谱仪对甲壳素及再生纳米甲壳素进行了表征。以辛酸/癸酸甘油三酯(GTCC)作为油相,用纳米甲壳素作为Pickering乳液稳定剂,制得水包油(O/W)型Pickering乳液。通过各类表征证明该方法制备的所有纳米甲壳素均可以乳化GTCC得到稳定的Pickering乳液(纳米甲壳素含量为0.2%)。随后其乳液的流变行为表明纳米甲壳素能很好地吸附在油水界面上,并且稳定Pickering乳液。

Nano-chitin was prepared by treating raw chitin with phosphoric acid(H_(3)PO_(4))for 40 min followed by high-pressure homogenization.This method could save chemical reagents,shorten the preparation process and increase the yield as compared with the previous preparation method.The chitin and regenerated nano-chitin(RCh)were characterized by XRD,TEM and inductively coupled plasma atomic emission spectrometry.The experimental conditions of preparation were optimized,such as the minimum concentration of phosphoric acid to dissolve chitin and the maximum concentration of chitin that could be dissolved by different concentrations of phosphoric acid.The RCh suspension thus prepared was used to stabilize caprylic/capric triglyceride(GTCC)to fabricate oil-in-water Pickering emulsions.The emulsions were characterized on an optical microscope,a dynamic laser scattering size analyzer and a rheometer.All the RCh prepared with this method could well stabilize Pickering emulsions(RCh content was only 0.2%).The RCh adsorbed on the O/W interface could stabilize the Pickering emulsions.The rheological behaviors of Pickering emulsions indicated that,the entanglement of RCh enhanced the structure of the emulsions as well as their resistance to deformation.The energy storage modulus and loss modulus remained constant with the change of scanning frequency at a fixed stress,and no intersection point was found in the frequency range,which indicated that the emulsions were stable and had“gel-like”behavior.All emulsions showed shear thinning behavior.RCh was effective in preventing droplet coalescence and could form stable Pickering emulsions when GTCC mass fraction was not higher than 60%.