Effect of the Chemical Structure of Compatibilizers on the Thermal, Mechanical and Morphological Properties of Immiscible PLA/PCL Blends

Summary This manuscript addresses the effect of the chemical structure of two block copolymers of low molecular weight employed as compatibilizers on the immiscible blends of poly(lactic acid) (PLA) and poly(ϵ‐caprolactone) (PCL). Binary and ternary blends were prepared by melt mixing in a twin screw extruder and the effect of the block copolymers on the morphological, mechanical and thermal behavior was investigated by scanning electron microscopy (SEM), tensile testing and differential scanning calorimetry (DSC). The addition of 5 wt% of block copolymers derived from ϵ‐caprolactone and 1,4 butanediol (C1) or ϵ‐caprolactone and an aliphatic polycarbonate (C2) maintained the size of the dispersed PCL domains practically constant, regardless of the PCL concentration. The compatibilized PLA/PCL blends containing 5 wt% of PCL exhibited a significant enhancement in elongation at break, in comparison to those of the neat PLA or uncompatibilized PLA/PCL blends. The DSC results show the melting temperatures of the PLA were not influenced by the chemical structure of the compatibilizers or PCL concentration. However, such variables changed the melting enthalpy of the PLA and PCL and melting temperature of the PCL.