中空マイクロカプセルの製造および超音波造影剤と薬物伝達システムへの応用

在2014年4月之前进行的研究中，我们发现改变聚乳酸(PLA)在二氯甲烷溶液中的浓度会产生对氮气的亨利定律常数的变化。这一点至关重要，因为如果气体在聚合物溶剂中的溶解度是从聚合物中去除挥发性气体的重要考虑因素，那么我们还有一个参数可用于设计微孔/泡沫或制备可生物降解的中空微胶囊和多孔膜，这是我们研究的最终目标。在2014年4月之后进行的研究中，通过测量在288至303K范围内溶解的聚乳酸对气体(二氧化碳、氮气和氦)在二氯甲烷中的溶解度的影响，通过测量封闭容器中包含一种气体和不同类型(相对分子质量)和浓度的二氯甲烷溶液的平衡压力来进行研究。结果表明，在没有聚乳酸存在的情况下，气体在二氯甲烷中的溶解度大小顺序为氦-氮-二氧化碳。此外，随着聚乳酸浓度的增加，二氧化碳在溶液中的溶解度没有明显变化，但导致氮和氦的溶解度增加。对于溶解度较低的气体，聚乳酸对气体在二氯甲烷中的溶解度增加的影响较大。由测量数据还得到了气体亨利定律常数与温度和聚乳酸浓度之间的半经验关联式。

In the studies performed before April 2014, we discovered that changing the concentration of poly lactic acid (PLA) in a solution of PLA in dichloromethane yield to a change in the Henry’s law constant for nitrogen. This is crucial because if the solubility of gases in polymer solvents is an important consideration in removing volatile gases from the polymers, we have one more parameter available for designing microcellular/foam or for fabricating biodegradable hollow microcapsules and porous films, which is the final objective of our study.In the studies performed after April 2014, the effect of dissolved PLA on the solubility of gases (carbon dioxide, nitrogen, and helium) in dichloromethane was investigated, between 288 and 303 K, by measuring the equilibrium pressure in a closed vessel containing a gas and dichloromethane solutions of different types (molecular weights) and concentrations of PLA. The results showed that, in the absence of PLA, the order of the solubility of gases in dichloromethane was helium < nitrogen < carbon dioxide. Furthermore, an increase in the concentration of PLA did not appreciably change the solubility of carbon dioxide in the solutions, but led to a higher solubility of nitrogen and He. The effect of PLA on the increase of gas solubility in dichloromethane was larger for less soluble gases. Semi-empirical correlations of the dependence of the Henry’s law constant of the gases on the temperature and PLA concentration were also derived from the measured data.