Mikrochim. Acta [Wien] 1988, I, 283--286 Mikrochimica 9 by Springer-Verlag 1988 Fourier Transform Infrared Study of Segmental Orientation in Polymer Blends Paul Chabot, Michel P6zolet*, and Robert E. Prud'homme Centre de Recherche en Sciences et Ing6nierie des Macromol6cules, D6partement de Chimie, Universit6 Laval, Sainte-Foy, Qu6bec G1K 7P4, Canada Abstract. The effect of the macromolecular plasticizer poly(a-methyl-a- n-propyl-fl-propiolactone), PMPPL, on the orientation of poly(vinyl chloride), PVC, has been studied by FTIR spectroscopy. The addition of PMPPL to PVC does not change significantly the degree of orientation of PVC segments. In blends, PMPPL chains are more oriented when the matrix is richer in PVC but the PMPPL orientation function always remains smaller than that of PVC segments. Key words: orientation, FTIR, polymer blends, PVC, PMPPL. Most plastic materials presently used in industry are oriented to a certain degree, i.e. their molecular segments present a direction of preferred alignment which results in an anisotropy of macroscopic properties. This orientation is normally induced during the processing, in particular if the material remains in the molten state. Poly(vinyl chloride) is one of the most frequently used commercial polymers and, in general, it contains a plasticizer which modifies PVC from a fragile material to a ductile polymer at room temperature. We have studied by Fourier-transform infrared spectroscopy the orien- tation of PVC chains induced by stretching. We have also studied the effect of a macromolecular plasticizer, poly(a-methyI-a-n-propyl-~-propiolac- tone), on the PVC orientation at PMPPL blend compositions varying from 0 to 50%. Experimental The orientation of PVC was followed by infrared linear dichroism using the bands due to the CH 2 bending modes in the region of 1400 to 1450 cm -1. * To whom correspondence should be addressed