Mechanical, thermal and morphological properties of poly(ε-caprolactone)/zein blends

Blends of poly(E-caprolactone) (PCL) with zein (PCL/zein) in different proportions (100/0, 75/25, 50/ 50, 25/75 and 0/100 wt% containing 5 wt% glycerol) were compared based on their mechanical properties (tensile strength, elongation at break, and Young's modulus), and on their thermal properties, the latter determined by thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA). The morphology of the materials was studied by scanning electron microscopy (SEM). Blends of PCL/zein showed reduced tensile strength and elongation at break, but increased Young's modulus compared to the pure polymers, in agreement with the DMTA and SEM results. These findings indicated that PCL and zein were incompatible. TGA showed that the thermal stability was enhanced by the addition of zein to PCL, whereas SEM showed a poor interfacial interaction between the polymers. Copyright (C) 2004 John Wiley Sons, Ltd.