ON THE ANALYSIS OF POSITRON-ANNIHILATION LIFETIME SPECTROSCOPY DATA IN SEMICRYSTALLINE MISCIBLE POLYMER BLEND SYSTEMS

A free volume probing technique, positron annihilation lifetime spectr oscopy (PALS) is used to characterize miscible blends of amorphous pol ycarbonate with a semicrystalline copolyester at room temperature. The paper describes the analysis required to use the PALS technique to pr obe the amorphous regions in which the miscibility of the blends occur s. Analysis of the raw PALS data in this system involves taking accoun t of the influence of crystallinity on the PALS results. The results d emonstrate that the PALS technique is able to discriminate between fre e volume in the amorphous regions of as-molded and annealed samples. T his difference in free volume between samples of differing thermal his tory is assigned to the influence of polymer crystals on the stress st ate of the miscible amorphous regions. (C) 1994 John Wiley & Sons, Inc .