ABSTRACT:Comparison between the effect of alcohols and diols on poly(methylmethacrylate) (PMMA) and polyacrylamide (PAA) was investigated by positron annihilation lifetime (PAL) spectroscopy and electric conductivity measurements. The samples were prepared by adding alcohols, such as ethanol (E), isopropyl alcohol (P), and butyl alcohol (B), and diols, such as ethanediol (E 1,2 ), isoproponendiol (P 1,2 ), and butanediol (B 1,2 , B 1,3 , B 1,4 ). The o-Ps lifetime values ( 3 ) of PMMA-alcohol or PMMA-diol composites are shorter than the 3 value of the virgin PMMA, whereas the 3 values of PAA-alcohol or PPA-diol composites fluctuate above and blow the corresponding value of virgin PAA. On the other hand, a significant increased was observed in the o-Ps intensities (I 3 ) of both PMMA and PAA composites with added alcohols and diols compared with pure PMMA and PAA. The electric conductivity () also increased for both PMMA and PAA composites with added alcohols and diols compared with the virgin PMMA or PAA polymer. A correlation was found between positron annihilation lifetime parameters and electric conductivity of PAA composites.

Polyhydroxamic acid (PHA) from polymethacrylamide (PMAA) was prepared. Chromium chloride (CrCl 3 ) and ferric chloride (FeCl 3 ) salts were added to the polymer in order to increase its electrical conductivity, i.e., the dopants help produce semiconducting properties. The positron annihilation lifetime technique spectroscopy (PALS) was used to study the changes in the free volume as a function of FeCl 3 and CrCl 3 concentrations. ortho-Positronium lifetime components were used to estimate the free volume parameters. It was found that the hole size and the total free volume fraction decreased with FeCl 3 concentration. On the other hand, the hole size increased slightly with CrCl 3 concentration and then decreased, while the total free volume fraction increased continuously. The free volume distributions were determined from ortho-positronium distributions. The electric conductivity as a function of FeCl 3 and CrCl 3 concentrations showed fluctuation behavior and showed a continuous increase with the increase in temperature. The correlation between positron annihilation parameters and electric conductivity were discussed.