Title :
Dielectric and thermal properties of irradiated polyetheretherketone
Author :
Shiyama, K. ; Fujita, S.
Author_Institution :
Hachinohe Inst. of Technol., Japan
fDate :
6/1/2001 12:00:00 AM
Abstract :
The dielectric and thermal properties of electron-beam-irradiated polyetheretherketone (PEEK) have been investigated and the properties of a heat-treated specimen studied. Results of the temperature dependence of εr\´ and εr" indicated that ε r\´ and εr" were higher after electron beam irradiation and lower after heat treatment. The temperature at which εr\´ begins to increase and that at which the peak of εr" appears, rise with both electron beam irradiation and heat treatment. Glass transition temperature Tg values were calculated from graphs depicting the relationship between logarithmic values of τ(Tm) data and Tm, through the use of the Williams-Landel-Ferry (WLF) equation. Tg shifted to higher temperatures with either irradiation or heat treatment Results suggest that electron beam irradiation causes crosslinking among molecules via free radicals in the specimen. Consequently, crosslinking among molecules via free radicals is thought to occur with heat treatment
Keywords :
dielectric relaxation; differential scanning calorimetry; electron beam effects; free radical reactions; glass transition; heat treatment; permittivity; plastics; polymers; radiation chemistry; DSC; PEEK; Williams-Landel-Ferry equation; crosslinking; dielectric properties; electron beam irradiation; free radicals; glass transition temperature; heat treatment; heat-treated specimen; permittivity; polyetheretherketone; temperature dependence; thermal properties; Dielectric loss measurement; Dielectric materials; Dielectric measurements; Dielectrics and electrical insulation; Electron beams; Glass; Heat treatment; Polymers; Resistance heating; Temperature;
Journal_Title :
Dielectrics and Electrical Insulation, IEEE Transactions on
