Radiation-Induced Polymerization of Vinylidene Chloride in Bulk and Included in Thiourea Crystals |
| |
Authors: | Franco Cataldo Ornella Ursini Pietro Ragni Valentina Lilla Giancarlo Angelini |
| |
Affiliation: | 1. Lupi Chemical Research Institute , Via Casilina 1626/A, 00133, Rome, Italy;2. INAF – Osservatorio Astrofisico di Catania , Via S. Sofia 78, 95123, Catania, Italy;3. Institute of Chemical Methodologies , CNR Via Salaria Km. 29,300 00016 Monterotondo Stazione, Rome, Italy |
| |
Abstract: | Vinylidene chloride (VDC) or 1,1-dichloroethylene was polymerized with γ radiation in bulk or as inclusion complex in thiourea crystals (inclusion polymerization). The resulting poly(vinylidenechloride) (PVDC) samples obtained from the two different polymerization techniques were characterized by FT-IR and electronic absorption spectroscopies, by ozonolysis and by thermal analysis (TGA, DTG and DTA). It was found that two selective secondary reactions occur in the two PVDC samples, respectively obtained from bulk polymerization or from inclusion polymerization. In the former case, the main reaction is only a crosslinking reaction, while in the latter case, with the PVDC included into the thiourea channels, the crosslinking reaction is fully inhibited and instead a dehydrohalogenation reaction takes place producing the polyene structures. The presence of polyene structures in the PVDC synthesized by the inclusion polymerization was demonstrated by electronic absorption spectroscopy and by ozonolysis experiments. The presence of polyene segments in the PVDC causes a reduction in the thermal stability of the polymer, lowers its melting point and reduces its crystallinity. |
| |
Keywords: | Poly(vinylidenechloride) PVDC radiation-induced polymerization bulk polymerization inclusion polymerization inclusion complex channel complex thiourea supramolecular chemistry chemical structure polyene chains ozonolysis FT-IR spectroscopy UV-VIS spectroscopy thermal analysis |
|
|