Structure and mechanical properties of blends of poly(ε-caprolactone) with a poly(amino ether)

Poly(epsilon-caprolactone) (PCL)/poly(amino ether) (PAE) blends were obtained by injection molding without any previous extrusion step in an attempt to (i) contribute to the knowledge of the relation between structure and mechanical properties in these type of blends composed of a rubber), and a glassy polymer and (ii) to find out to which extent are the PCL/PAE blends compatible, and therefore whether the biodegradability of PCL can be added as a characteristic of PAE-based applications. PCL/PAE blends are composed of a crystalline PCL phase, a pure amorphous PCL phase, and a PAE-rich phase where some PCL is present. The presence of some dissolved and probably unreacted PCL in the PAE-rich phase led to a low interfacial tension as observed by the small size of the dispersed particles and the large interfacial area. The dependence on composition of both the modulus of elasticity and the yield stress of the blends was parallel to that of the orientation level. The elongation at break showed values similar to those of PAE in PAE-rich blends, and was slightly synergistic in very rich PCL compositions; this behavior reflects a change in the nature of the matrix, from glassy to rubbery. (C) 2008 Wiley Periodicals, Inc.