Glass–Rubber Transitions of Cellulosic Polymers by Dynamic Mechanical Analysis

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 us...

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Bibliographic Details
Published in:Journal of pharmaceutical sciences 1990-09, Vol.79 (9), p.845-848
Main Authors: Kararli, Tugrul T., Hurlbut, Jeffrey B., Needham, Thomas E.
Format: Article
Language:English
Subjects:
Applied sciences
Cellulose - analogs & derivatives
Cellulose - chemistry
Cellulose and derivatives
Chemical Phenomena
Chemistry, Physical
Exact sciences and technology
Glass
Hypromellose Derivatives
Methylcellulose - analogs & derivatives
Natural polymers
Physicochemistry of polymers
Polymers - chemistry
Rubber
Temperature
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Summary: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°C, respectively. The primary Tg of the HEC film was determined as 120°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°C and 190 to 195°C, respectively. The HEC powder did not exhibit a melting temperature, but became darker at temperatures >150°C.
ISSN:0022-3549
1520-6017
DOI:10.1002/jps.2600790922