Studies of the Polydiacetylene Bis-p-chlorocinnamate of 10,12-Docosadiyn-1,22-diol

Abstract

The bis-p-chlorocinnamate of 10,12-docosadiyn-1,22-diol polymerized with ⁶⁰Co gamma radiation to give a soluble polydiacetylene (PDA), PDA-ClCIN-22. We have studied PDA-ClCIN-22 in both crystallographic powder and solution coated films. Thin films of solution coated PDA-ClCIN-22 exhibit an absorption maximum of 544 nm, similar to the concentrated solution in chlorobenzene. Irradiation of these films with 254 nm UV light in air leads to loss of intensity in the visible spectrum. The thin films of PDA-ClCIN-22 are amorphous by X-ray powder diffraction. Irradiation of both PDA-ClCIN-22 powder and film with 254 nm light did not result in photochemical reactivity of the chlorocinnamate group as recorded by FTIR spectra. Differential scanning calorimetry (DSC) studies of PDA-ClCIN-22 reveal that presence of monomer and endothermic transitions near 116°C and 134°C on a first heating. On a second heating of a sample of PDA-ClCIN-22 taken to 150°C on first heating, the 116°C and 134°C endotherms are absent. These endotherms are also lost by monomer extraction with boiling cyclohexane. One possible source of the endotherms would be conformational transitions in the side chain.

Keywords:

• PDA ClCIN-22
• ⁶⁰Co gamma radiation
• ultraviolet degradation

Acknowledgements

The authors thank M.J. Downey for furnishing X-ray powder diffraction data. Access to the gamma radiation source was facilitated by Ms. Mary Montesalvo. S.E. Cankaya is a M.S. Candidate in the Materials Science and Engineering Program at the University of Kiel, Germany.