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Thermal and dynamic mechanical properties of hydroxypropyl cellulose films
Author(s) -
Rials Timothy G.,
Glasser Wolfgang G.
Publication year - 1988
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1988.070360402
Subject(s) - differential scanning calorimetry , dynamic mechanical analysis , materials science , glass transition , crystallinity , thermal analysis , mesophase , amorphous solid , thermomechanical analysis , polymer chemistry , hydroxypropyl cellulose , composite material , polymer , chemical engineering , liquid crystal , crystallography , thermal , thermodynamics , chemistry , thermal expansion , physics , optoelectronics , engineering
Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) were used to characterize the morphology of solvent cast hydroxypropyl cellulose (HPC) films. DSC results were indicative of a semicrystalline material with a melt at 220°C and a glass transition at 19°C ( T 1 ), although an additional event was suggested by a baseline inflection at about 80°C ( T 2 ). Corresponding relaxations were found by DMTA. A secondary relaxation at −55°C was attributed to the interaction between hydroxyl groups of the polymer and residual diluent. The tan δ peak at T 2 was found to arise from an organized phase, presumably from a liquid‐crystal mesophase formed while in solution. Crosslinking with a diisocyanate increased the peak temperature of the two primary relaxations, and resulted in a more clearly defined peak for the T 2 transition. From this behavior it was concluded that both T 1 and T 2 are similar to glass transitions ( T g 's) associated with an amorphous component and a more highly ordered phase (due to a residual liquid crystal superstructure) in the HPC bulk.