Electron beam irradiation of polytetrafluoroethylene in vacuum at elevated temperature: An infrared spectroscopic study

Abstract

Electron beam irradiation of polytetrafluoroethylene (PTFE) has been performed in vacuum both at elevated temperature above the melting point of PTFE and at room temperature for comparison. The changes in the chemical structure were studied by Fourier-transform infrared (FTIR) spectroscopy. The formation of double bonds in PTFE was confirmed as a result of irradiation in vacuum. Moreover, trifluoromethyl (CF 3 ) branches were detected. The concentration of CF 3 branches was found to be much higher in irradiation at elevated temperature than in room temperature irradiation. The CF 3 branches are assumed to cause the reduced crystallinity indicated by the transparency of PTFE specimens irradiated in the molten state.

Modification of PTFE nanopowder by controlled electron beam irradiation: A useful approach for the development of PTFE coupled EPDM compounds

“…Significant developments were also made both in the synthesis and manufacturing of new commercial fluorpolymers with improved mechanical properties [11][12]. However, electron beam modification provides a simple and effective method for modification of PTFE powder [13][14][15][16][17][18][19][20]. Recently, newly developed chemically coupled PTFE-PA compounds have opened a new way in producing high performance wearresistant materials [21][22][23].…”

Cross-linking of polytetrafluoroethylene during room-temperature irradiation

“…The spectra from each layer of a given seven layer PTFE sample were averaged in order to obtain spectra representative of the entire thickness damaged by a-radiation. This was achieved by normalizing spectra to the intensity of the mode at 2366 cm À1 , which has previously been shown to be useful as an ''internal standard'' for FTIR spectra of PTFE [16].…”

“…Table 1 Assignments of spectral features observed in FTIR data of virgin and a-irradiated PTFE. Previously determined assignments and corresponding observed energies in FTIR spectra are included [7,16,25,28,29,31]. The virgin PTFE spectrum shows several modes between 800 and 700 cm À1 , as seen in Fig.…”

“…More recent studies of PTFE irradiated at elevated temperatures found different results [4][5][6]9,[15][16][17]. Chain-scission induced degradation of PTFE's properties increased with increasing temperature up to the melting point.…”

Construction of mechanically durable superhydrophobic surfaces by thermal spray deposition and further surface modification

“…The intense peak located at 1000-1500 cm -1 is assigned to stretching vibration of a variety of CFx species [27]. The band at 1792 cm -1 refers to terminal double bonds (-CF=CF2-) and the band at 2365 cm -1 is attributed to a combination band of the two modes associated with the CF 2 backbone [28]. The Al coatings were fabricated as the top rough layer on these substrates.…”