Interaction between water and polytrans-2,5-dimethylpiperazin thiofurazanamide films
✍ Scribed by Mario Pegoraro; Amabile Penati
- Book ID
- 103060005
- Publisher
- Elsevier Science
- Year
- 1983
- Tongue
- English
- Weight
- 587 KB
- Volume
- 48
- Category
- Article
- ISSN
- 0011-9164
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✦ Synopsis
Dense films of polytrans-2,5<iimethylpiperazin thiofurazanamide (DMP-TFZ) were characterized as to their physical properties and sorption isotherms. They appeared to be amorphous, endowed with high Tg (247°C), and high mechanical stiffness.
Sorption and desorption equilibrium curves were obtained at 23°C for samples 26 and 36 pm thick; hysteresis phenomena were observed only in the desorption steps. BET and Burhoff-Pusch theories and best fit calculations allowed to find that the water layers on the active sorption centers are n = 5 and 1.6 respectively.
The Zimm water cluster integral G ll/v 1 shows that water tends to be split in single adsorbed molecules in a large field of activities, but that cluster formation is unavoidable in the presence of liquid water. Infrared analysis of the OH stretching region of films conditioned at different relative humidity (RH), demonstrates that water hydrogen bonds in the sorbed state are weaker than in the liquid state and that the presence of big water clusters able to dissolve salts must be excluded. The close packing and high rigidity of the chains should be responsible for the free volume small size holes and uniform distribution, which does not allow big water clusters.