Chemical modification of Hyflon® AD copolymer end groups by means of physical and chemical treatments. A joint spectroscopic and quantum chemical investigation

• Chemical modifications occurring in a class of amorphous fluorinated polymers have been investigated.
• The adopted experimental tool is Vibrational Spectroscopy.
• Quantum chemical calculations allowed to rationalize experimental data.
• The joint experimental and theoretical approach shed light on the physico-chemical phenomena occurring.

In this paper is presented a study on the effects of physical treatments, namely electron beam irradiation or fluorination, on a perfluoropolymer copolymer of tetrafluoroethylene with 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole (Hyflon® AD copolymer). The analysis has been carried out by means of IR spectroscopy and quantum chemical modeling based on density functional theory; this combined experimental/theoretical approach has proven effective for the interpretation of previously unassigned IR bands, which are associated to functional groups generated by polymer degradation and chain scission. We performed a systematic screening of chemical groups and structures compatible with degradation pathways that are possible from the chemical point of view: the chemical mechanisms and the correlation with the spectroscopic experimental data (both frequency and intensity) provide guidelines in understanding the phenomena. Moreover, the spectroscopic experimental/theoretical and chemical approaches allowed us to identify some chemical structures responsible for the unassigned IR bands in the CO stretching frequency region above 1800 cm−1, which is typical for carbonyl groups in fluorinated systems.

Figure optionsDownload as PowerPoint slide