Plasticizing effect of water on poly(lactide-co-glycolide)
Plasticizing effect of water on poly(lactide-co-glycolide)
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DOI：
10.1016/j.jconrel.2005.07.009
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发表时间：
2005-11-02
影响因子：
10.8
通讯作者：
DeLuca, PP
中科院分区：
文献类型：
--
作者：
Blasi, P;D'Souza, SS;DeLuca, PP
本研究的目的是评估水合作用对聚（D，L-丙交酯-共-乙交酯）的玻璃化转变温度（T，）的影响和性质，并研究湿热老化过程中聚合物中水的物理状态。将聚合物在23、30、37和55 ℃的水中孵育，而蒸气吸附研究在37 ℃下使用饱和盐溶液进行。采用卡尔费休滴定法和调制式差示扫描量热法分别测定PLGA-水体系的含水量和热行为，采用凝胶渗透色谱法监测其湿热老化过程。无论孵育条件如何，水可逆地使T-g降低约15 ° C。然后，除了发生降解时，T在类似于30摄氏度的温度下保持恒定五天。在0摄氏度左右检测到一个宽的融冰峰。在吸附研究中，在0.3- 2.6%w/w范围内观察到T-g和水分含量之间的线性相关性（r（2）0.9837），但没有与冰的融化相关的可辨别的吸热事件。发现数据与Gordon-Taylor/Kelley-Bucche方程相当吻合。散装和蒸汽水老化之间没有差异。有人提出，负责塑化聚合物的水是不可冻结的（结合）水，在高相对湿度下吸收的小部分这样的水以与本体水相同的方式引起聚合物降解。(c)2005 Elsevier B.V保留所有权利。
The purpose of this research was to evaluate the effect and nature of hydration on the glass transition temperature (T,) of poly(D,L-lactide-co-glycolide) and investigate the physical state of water within the polymer during hygrothermal aging. The polymer was incubated in water at 23, 30, 37 and 55 degrees C, while the vapor sorption studies were carried out at 37 degrees C using saturated salt solutions. The water content and the thermal behavior of PLGA-water system were assessed by Karl Fischer titration and modulated differential scanning calorimetry, respectively, the hygrothermal aging was monitored by gel permeation chromatography. Water depressed reversibly the T-g by about 15 degrees C regardless of the incubation conditions. The T, then remained constant at similar to 30 degrees C for five days, except when degradation occurred. A broad ice melting peak was detected around 0 degrees C. In the sorption studies, a linear correlation (r(2) 0.9837) between the T-g and the moisture content was observed in the range of 0.3-2.6% w/w, but there was no discernible endothermic event associated with the melting of ice. Data were found to fit reasonably well to the Gordon-Taylor/Kelley-Bucche equation. There were no differences between bulk and vapor water aging. It is proposed that the water responsible for plasticizing the polymer was non-freezable (bound) water and the small fraction of such water which was absorbed at high relative humidity caused polymer degradation in the same manner as bulk water. (c) 2005 Elsevier B.V All rights reserved.