Guo J H
3M Pharmaceuticals, Pharmacy Research and Development, St. Paul, MN 55144-1000.
J Pharm Sci. 1994 Mar;83(3):447-9. doi: 10.1002/jps.2600830337.
The effects of physical aging and antiplasticization on the water transport properties of glassy cellulose acetate film-coated tablets were investigated. The gradual approach toward thermodynamic equilibrium during physical aging decrease the free volume of the polymers. This decrease in free volume is accompanied by a decrease in the transport mobility, with concomitant changes in those properties of the polymer that depend on it. Antiplasticization arises from an interaction between the polymer and the plasticizer molecules and decreases the molecular mobility of the polymer and plasticizer. This effect was confirmed by mechanical measurements of polymer free films at the same experimental temperature. We have studied the additive effect of aging and antiplasticizing to see if the individual effects would interfere with one another, as might be expected if the same free volume were involved in each. The pronouncedly additive effects of physical aging and antiplasticization on the water permeability can be found in cellulose acetate film-coated tablets that were affected by longer physical aging time and lower plasticizer concentration. A theoretical study suggested that the free volume in the glassy polymer should consist of at least two independent parts, one of which is affected by annealing and the other by antiplasticization.
研究了物理老化和反增塑作用对玻璃态醋酸纤维素薄膜包衣片水传输性能的影响。物理老化过程中向热力学平衡的逐渐趋近降低了聚合物的自由体积。自由体积的这种减少伴随着传输迁移率的降低，同时聚合物那些依赖于自由体积的性能也发生了相应变化。反增塑作用源于聚合物与增塑剂分子之间的相互作用，降低了聚合物和增塑剂的分子迁移率。在相同实验温度下对聚合物自由膜进行的力学测量证实了这种效应。我们研究了老化和反增塑的加和效应，以查看个体效应是否会相互干扰，就如同如果两者涉及相同自由体积时可能预期的那样。在物理老化时间较长且增塑剂浓度较低的醋酸纤维素薄膜包衣片中，可以发现物理老化和反增塑对水渗透性有明显的加和效应。一项理论研究表明，玻璃态聚合物中的自由体积应至少由两个独立部分组成，其中一部分受退火影响，另一部分受反增塑影响。
