Authors Dlubek, G. ; Pionteck, J. ; Bondarenko, V. ; Pompe, G. ; Taesler, C. ; Petters, K. ; Krause-Rehberg, R.
Title Positron Annihilation Lifetime Spectroscopy (PALS) for Interdiffusion Studies in Disperse Blends of Compatible Polymers: A Quantitative Analysis
Date 06.08.2002
Number 10435
Abstract Positron annihilation lifetime spectroscopy (PALS) and differential scanning calorimetry(DSC) were used to study the interdiffusion in a particle-matrix system consisting of the miscible polymerspoly(vinyl chloride) (particles) and poly(<I>n</I>-butyl methacrylate) (matrix, 30:70 and 50:50 w/w). Startingfrom the demixed state of the blends, the transition to the mixed state during annealing at 110 <IMG SRC="/images/entities/deg.gif">C wasinvestigated. We deliver further evidence that PALS parameters such as the orthopositronium intensity<I>I</I><SUB>3</SUB> and the average positron lifetime <I><IMG SRC="/images/gifchars/tau.gif" BORDER=0 ></I><SUB>av</SUB> respond to chemical inhomogeneities in blends and theirdisappearance due to mutual diffusion of molecules of both phases. The response is due to inhibition ofPs formation by one of the constituents when its molecules migrate into the phase made from the secondone. A core-shell model for the description of the o-Ps response to a local chemical inhomogeneity isdeveloped which makes use of a calculated concentration-distance profile. The comparison with theexperiment allows the estimation of the interface width and of kinetic parameters<br />, such as the exponentof the time dependence of the interface width and the coefficient of mutual diffusion. The potential andthe limitation of this new technique are discussed.
Publisher Macromolecules
Citation Macromolecules 35 (2002) 6313-6323

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