Embrittlement of poly (L-lactide)/poly (ε-caprolactone) blends upon physical aging

Toughening of poly (L-lactide) (PLLA) by flexible poly (ε-caprolactone) (PCL) is very attractive for biomedical applications. However, PLLA/PCL blends usually behave brittle fracture, which is ascribed to the immiscibility between two components. This study demonstrates that without physical aging dispersed PCL particles can induce significant ductile deformation of PLLA matrix, accompanied by remarkable decreasing of yield strength, opposite to what is observed in the aged blends. It is deduced that segmental mobility of PLLA matrix and crystalline order of PCL domains, rather than immiscibility, play vital role in determining the ductility of PLLA/PCL blends.