Thermally Stimulated Relaxation and Electrical Conduction Phenomena In Polyacrylamide
نویسنده
چکیده
Thermally stimulated relaxation (TSR), employing thermally stimulated luminescence (TSL) and thermally stimulated conductivity (TSC) as experimental techniques, in Polyacrylamide (PAA) have been studied; in the temperature range 300 480 K. Measurements of electrical conductivity () at various temperatures, in the same temperature range have been made, in both as-grown and UV-irradiated PAA films; to elucidate the mechanism of charge transport in relation to the macromolecular relaxations in PAA. Two TSL and TSC glow curves with maxima at 375 and 475 K have been observed. The log vs 1/T plots showed two transition temperatures with changes in slopes; indicating the on-set of molecular motion in PAA. The TSL/TSC curves at 475 K are attributed to the relaxation near the glass transition temperature of the polymer. The -relaxation is considered to be associated with the glow curve at 375 K. Analysis of TSL / TSC curves and electrical conductivity plots have been made and the results are correlated. The two endothermic peaks recorded by Differential scanning calorimetry (DSC) are correlated with the TSL/TSC and relaxations in Polyacrylamide.
منابع مشابه
Thermally Stimulated Currents in Nanocrystalline Titania
A thorough study on the distribution of defect-related active energy levels has been performed on nanocrystalline TiO₂. Films have been deposited on thick-alumina printed circuit boards equipped with electrical contacts, heater and temperature sensors, to carry out a detailed thermally stimulated currents analysis on a wide temperature range (5-630 K), in view to evidence contributions from sha...
متن کاملDielectric spectroscopy and thermally stimulated discharge current in PEEK film
The complex permittivity of films of polyether ether ketone (PEEK) has been investigated over a wide range of frequency. There is no relaxation peak in the range of 1Hz to 10 Hz but in the lowfrequency side (10 Hz) there is an evidence of a peak that also can be observed by thermally stimulated discharge current measurements. That peak is related with the glass transition temperature (T g ) of ...
متن کاملThermally Stimulated Currents in Nanocrystalline
A thorough study on the distribution of defect-related active energy levels has been 18 performed on nanocrystalline TiO2. Films have been deposited on thick-alumina printed circuit 19 boards equipped with electrical contacts, heater and temperature sensors, to carry out a detailed 20 thermally stimulated currents analysis on a wide temperature range (5-630K), in view to evidence 21 contributio...
متن کاملElectrical conduction and dielectric relaxation in p-type PVA/CuI polymer composite
PVA/CuI polymer composite samples have been prepared and subjected to characterizations using FT-IR spectroscopy, DSC analysis, ac spectroscopy and dc conduction. The FT-IR spectral analysis shows remarkable variation of the absorption peak positions whereas DSC illustrates a little decrease of both glass transition temperature, Tg , and crystallization fraction, χ, with increasing CuI concentr...
متن کاملMultiple photonic responses in films of organic-based magnetic semiconductor V(TCNE)x, x approximately 2.
Concomitant photoinduced magnetic and electrical phenomena are reported for the organic-based magnetic semiconductor V(TCNE)x (x approximately 2; TCNE=tetracyanoethylene; magnetic ordering temperature Tc approximately 400 K). Upon optical excitation (457.9 nm), the system can be trapped in a thermally reversible photoexcited state, which exhibits reduced magnetic susceptibility and increased co...
متن کامل