Miscibility study of solution cast blends of poly(lactic acid) and poly(vinyl butyral)

Abstract

Poly(lactic acid) (PLA) was blended with poly(viny1 butyral) (PVB) through solution casting method using chloroform as the common solvent. The films obtained were characterized for miscibility using Differential Scanning Calorimetry (DSC), tensile testing and FTIR spectroscopy. The DSC results showed that the glass-transition temperature (Tg) of the PLA and PVB remained more or less constant with the composition of the blend. The existence of two Tg’s in the blends indicated that PLA and PVB were immiscible over the composition range investigated. percentage crystallinity ( cc ), of PLA phase remained constant with increasing PVB content in the blend. FTIR measurements showed that there was no appreciable change in the spectra with respect to blend composition, implying the immiscibility of the two polymers. Mechanical analysis showed that the tensile strength and elongation decreased on blending.