HEAT CAPACITY OF LINEAR HIGH POLYMERS.
RENSSELAER POLYTECHNIC INST TROY N Y DEPT OF CHEMISTRY
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All available data on heat capacities of linear high polymers have been critically reviewed and discussed in terms of the vibrational frequency spectrum. Several characteristic temperature regions could be delineated. Below 50K the heat capacity is conformation, crystallinity, and defect dependent. For crystalline polymer a T3 temperature dependence is generally found below 10K. Above 50K up to the glass transition temperature the heat capacity is largely independent of conformation crystallinity and defects. The absolute value of the heat capacity is largely additive from contributions of the chain atoms. The increase of heat capacity at the glass transition temperature of amorphous polymers is constant if calculated per mole of mobile bead. Between the glass transition and melting transition of semicrystalline polymers uncertainties arise due to instabilities of the metastable crystals. Melting behavior has been briefly reviewed. The heat capacities of the melt have been discussed where available. Only for polyethylene could a detailed interpretation be given. Author
- Atomic and Molecular Physics and Spectroscopy