The study of the thermal behavior of a new semicrystalline polyimide. Final Technical Report
Thermal properties of a new semicrystalline polyimide synthesized from 3,3',4,4' benzophenone tetracarboxylic dianhydride (BTDA) and 2,2 dimethyl 1,2-(4 aminophenoxy) propane (DMDA) were studied. Heat capacities in the solid and liquid states of BTDA-DMDA were measured. The heat capacity increase at the glass transition temperature (T sub g = 230 C) is 145 J/(C mol) for amorphous BTDA-DMDA. The equilibrium heat of fusion of the BTDA-DMDA crystals was obtained using wide angle X ray diffraction and differential scanning calorimetry measurements, and it is 75.8 kJ/mol. Based on the information of crystallinity and the heat capacity increase at T sub g, a rigid amorphous fraction is identified in semicrystalline BTDA-DMDA samples. The rigid amorphous fraction represents an interfacial region between the crystalline and amorphous states. In particular, this fraction increases with the crystallinity of the sample which should be associated with crystal sizes, and therefore, with crystal morphology. It was also found that this polymer has a high temperature crystal phase upon annealing above its original melting temperature. The thermal degradation activation energies are determined to be 154 and 150 kJ/mol in nitrogen and air, respectively.
- Research Organization:
- Akron Univ., OH (United States)
- OSTI ID:
- 7047697
- Report Number(s):
- N-92-25611; NASA-CR-190337; NAS-1.26:190337; CNN: NAG3-1288
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
IMIDES
THERMODYNAMIC PROPERTIES
POLYMERS
ACTIVATION ENERGY
AMORPHOUS STATE
ANHYDRIDES
ANNEALING
CALORIMETRY
CRYSTAL STRUCTURE
FUSION HEAT
MELTING
SPECIFIC HEAT
SYNTHESIS
TEMPERATURE EFFECTS
THERMAL DEGRADATION
TRANSITION TEMPERATURE
X-RAY DIFFRACTION
COHERENT SCATTERING
DIFFRACTION
ENERGY
ENTHALPY
HEAT TREATMENTS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SCATTERING
TRANSITION HEAT
360606* - Other Materials- Physical Properties- (1992-)