Kararli T T, Hurlbut J B, Needham T E
Searle Research and Development, Skokie, IL 60077.
J Pharm Sci. 1990 Sep;79(9):845-8. doi: 10.1002/jps.2600790922.
The glass-rubber transition temperatures (Tg) of several cellulosic polymers [hydroxypropyl methylcellulose (HPMC), hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC)] have been examined using dynamic mechanical analysis (DMA). The melting temperatures of the above polymers were examined using a hot stage melting point apparatus. The primary Tg of three different grades of HPMC (3, 6, and 15 cps) were determined to be 160, 170, and 175 degrees C, respectively. The primary Tg of the HEC film was determined as 120 degrees C. The HPC film did not indicate a primary Tg. These cellulosic polymers also displayed secondary transitions. Hot stage melting of HPMC and HPC was observed at 225 to 254 degrees C and 190 to 195 degrees C, respectively. The HEC powder did not exhibit a melting temperature, but became darker at temperatures greater than 150 degrees C.
已使用动态力学分析（DMA）对几种纤维素聚合物[羟丙基甲基纤维素（HPMC）、羟丙基纤维素（HPC）、羟乙基纤维素（HEC）]的玻璃化转变温度（Tg）进行了检测。使用热台熔点仪对上述聚合物的熔点进行了检测。三种不同等级的HPMC（3、6和15厘泊）的主要玻璃化转变温度分别测定为160、170和175摄氏度。HEC薄膜的主要玻璃化转变温度测定为120摄氏度。HPC薄膜未显示出主要玻璃化转变温度。这些纤维素聚合物还表现出二级转变。观察到HPMC和HPC的热台熔点分别在225至254摄氏度和190至195摄氏度。HEC粉末未表现出熔点，但在高于150摄氏度时颜色变深。
