壳聚糖-聚乳酸接枝共聚物多孔支架制备

天然聚合物壳聚糖，生物可降解材料聚乳酸，都有着良好的生物相容性，在生物医学领域有着广泛的用途。但是，壳聚糖与聚乳酸各自的性能缺陷导致了这两者单独使用有着很大的局限性。为了改善这两者的缺点，可以利用将聚乳酸接枝共聚到壳聚糖主链上。这样既可以改善壳聚糖不易于加工的缺点，而壳聚糖本身碱性多糖的结构也可以中和乳酸降解过程中所产生的酸性。本文介绍了壳聚糖-聚乳酸接枝共聚体系的制备方法。

Preparation methods on chitosan-PLA copolymer

In this paper, the binary interaction parameters needed to calculate the vapor-liquid equilibrium of dimethyl ether （DME）-methanol system have been investigated by chemical process simulation software Aspen Plus when NRTL model was used for liquid phase and PR equation for vapor phase. Firstly, the vapor-liquid equilibrium of dimethyl ether-methanol system was calculated through binary interaction parameters which come from Aspen Plus own database VLE-LIT,VLE-RK and VLE-HOC, the results showed that the calculation values were in good agreement with the experiment values when binary interaction parameters of database VLE-RK and VLE-HOC were used, and the calculation results of database VLE-RK was better. Secondly, by fitting the experimental data of literature, the binary interaction parameters were estimated again. For NRTL model： a12=1.486, a21=-1.1496, b12=- 28.06, b21=194.7, c12=0.0172; and for PR equation： k12=kza=-0.0605. The calculation result of the vapor-liquid equilibrium with these parameters was best.