Temperature and Weight Dependence of Free Volumes in Conducting Composite Polymer Using Positron Annihilation Techniques

Abstract

Polyvinylidene fluoride-co-hexafluoropropylene (PVdF-co-HFP) with conducting polyaniline (PAni) was studied to measure free-volume intensity (I 3 ), orthopositronium (o-Ps) lifetime ( 3 ), and Doppler momentum distribution parameters (S and W) as a function of temperature varying from 273 to 373 K and PAni weight percentage varying from 1 %-20 % using the techniques of Positron Annihilation Lifetime Spectroscopy (PALS) and Doppler Broadening Annihilation Radiation (DBAR). It has been observed that the free-volume intensity and the o-Ps lifetime increased sharply with PAni weight percentage up to 4 % after which decreased slowly. DBAR momentum distribution parameters behaved similarly as well and it's assumed that in the studied samples one-type defect was to exist. The thermal expansion coefficient also as a function of PAni weight was extracted from PALS data.

Free volume, thermal and morphological properties of photo-crosslinked thiol-Ene/ nanodiamond hybrid network

“…In polymers, the expression between the hole free volume size ( υ f ) and the free volume fraction ( f υ ) is given by: where A is the proportionality constant (Tav and Yilmazturk, 2011; Wang et al , 1990). In Figure 7, the o-Ps lifetime (or the hole free volume) and free volume fractions were plotted against the weight percentages of T/M-ND nanocomposites for some temperatures.…”

“…The converted signals are sent to a multichannel analyzer (Ortec Model 919E Ethernim MCA) to analyze spectroscopic data by the code of RESOLUTION revealing the lifetime parameters about the free volume in the positron annihilation lifetime spectroscopy (PALS) system (Shakun et al , 2019). The PALS yields two independent parameters as the intensity and the lifetime of o-Ps, related with hole numbers and hole size (or hole free volume), respectively (Jean et al , 2003; Tav and Yilmazturk, 2011).…”

“…We are interested in (Shakun et al, 2019). The PALS yields two independent parameters as the intensity and the lifetime of o-Ps, related with hole numbers and hole size (or hole free volume), respectively (Jean et al, 2003;Tav and Yilmazturk, 2011).…”