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）溶液中聚乳酸（PLA）在二氯甲烷产量中的浓度会改变氮的亨利定律常数。这是至关重要的，因为如果气体在聚合物溶剂中的溶解度是去除聚合物中挥发性气体的重要考虑因素，我们就有了一个可用于设计微孔/泡沫或制造可生物降解的空心微胶囊和多孔膜的参数，这是我们研究的最终目标。在2014年4月之后进行的研究中，通过测量含有不同类型（分子量）和PLA浓度的气体和二氯甲烷溶液的密闭容器中的平衡压力，研究了溶解的PLA对气体（二氧化碳、氮和氦）在二氯甲烷中的溶解度的影响，在288 - 303 K之间。结果表明，在没有PLA的情况下，气体在二氯甲烷中的溶解度顺序为氦<氮<二氧化碳。此外，PLA浓度的增加并没有明显改变二氧化碳在溶液中的溶解度，但导致氮和He的溶解度提高。PLA对二氯甲烷气体溶解度的提高作用在可溶性较差的气体中更大。根据实测数据，得到了气体的亨利定律常数与温度和聚乳酸浓度的半经验相关关系。

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.