The Effect of Molecular Weight of Polycaprolactone on the Ester Interchange Reactions during Melt Blending with Poly(ethylene terephthalate)

The molecular weight (MW) of polycaprolactone (PCL) component had a profound effect on the ester interchange reactions during melt blending with poly(ethylene terephthalate) (PET). Utilization of lower MW of PCL component gave rise to higher degree of ester interchange reactions, and it could reduce mixing time required for generating a copolyester. The thermal properties and crystalline structure of resultant copolyesters were depended on the degree of ester interchange reactions by varying MW of PCL. It converted the morphology of copolyesters to a continuous single phase, suggesting formation of more random copolyester. Further, the substitution of PCL with low MW (Mw: 1250) as third component in melt blends of PET and PCL with high MW(Mw: 80000) led to higher degree of ester interchange reactions as well.