Photoacoustic investigation of iodine-doped polystyrene

Abstract

The kinetics of iodine doping of atactic polystyrene films is investigated using photoacoustic spectroscopy. The changes in the photoacoustically measured physical properties, such as nonradiative relaxation time and thermal diffusivity, are present as a function of the doping time. The results show strong evidence that an order-disorder transition is taking place as a function of the doping time. The suggested order-disorder transition is also evident in the dielectric constant measurements of the doped films.

Photoacoustic Monitoring of Internal Plastification in Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Copolymers: Measurements of Thermal Parameters

“…As it is well known, the modulation frequency dependence of the PA signal is the usual way for extracting information about the thermal diffusivity of the material under investigation. For the present case of thermally thick samples [sample thickness l exceeds the thermal diffusion length µ = (α/πf) 1/2 , where f is the modulation frequency of the incident light] it can be shown 7,8,13 that the thermal diffusitivy α is obtainable by fitting [coefficient a = (πl 2 /α) 1/2 ] the measured amplitudes of the PA signal,…”

“…The significance of α as a physical parameter to be monitored is due to the fact that like the optical absorption coefficient, it is unique for each material. Furthermore, the thermal diffusivity is extremely dependent upon the effects of composition and micro-structural variables, as well as processing conditions as in the case of foodstuffs 7 , polymers 13 , semiconductors 8,14 , and solvent evaporation 15 . This can be appreciated from the tabulated values of α presented by Touloukian et al 16 for a wide range of materials.…”

Analysis of the fracture behavior of epoxy resins under impact conditions

“…Since this technique was developed, 12,13 it has been applied in the thermal and optical charac- terization of materials, such as polymers, 14,15 glasses, 16 and plant leaves. 17,18 In contrast to the conventional photoacoustic (PA) method (for a review of photoacoustic spectroscopy, see, for example, Refs.…”

Determination of Thermal and Sorption Properties of Poly-3-Hydroxy Octanoate Using Photothermal Methods

“…As is well known, the modulation frequency dependence of the PA signal is the usual way for extracting information about the thermal diffusivity of the material under investigation [7,8,14].…”