Influence of polymer solution composition on the microstructure and thermal and mechanical characteristics of polycaprolactone films

Abstract

This study investigates the effects of addition of oils and alkanes to the polymer solution on the properties of polycaprolactone (PCL) films. The films were prepared by casting films onto a mold and evaporation in air. Films made without oils showed a dense microstructure. Most of the oils generated porous films, except for cyclohexane and castor oil. The neat PCL and cyclohexane films were stronger than other films, with a tensile strength of about ~11.5 MPa, followed by terpenes (~6.5 MPa) and the weakest films were obtained with hexadecane (~3.5 MPa). The elastic modulus was highest with limonene (~350 MPa), followed by cyclohexane (~150 MPa), and the lowest modulus (~65 MPa) was obtained with castor oil and hexadecane. All films showed high elongation at break (>400%). The degree of crystallinity was the highest with terpenes, whereas the lowest crystallinity was obtained with hexadecane. No significant effect of the oils on the thermal transition temperatures of the films could be observed. In summary, the microstructure and mechanical properties of the PCL films could be effectively fine-tuned for various applications through the addition of oils and alkanes to the polymer solution.