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.Highlights Oils and alkanes were added to polycaprolactone (PCL) casting solution. PCL films were prepared by casting films onto a mold and evaporation in air. Oils affected the microstructure and mechanical properties of the films. Addition of oils provides a flexible tool to tailor the film properties. PCL films with varying properties could be fabricated for different fields.

Undesired films with brilliant whiteness produced from a transparent amorphous polymer solution during room temperature evaporation or water washing

“…Solution casting method is a classical way to prepare polymer films by depositing a polymer solution into a mold, as the solvent evaporates the polymer chains interpenetrate, going through a gel state then forming the film with further evaporation. 1,2 In the industrial field, solution casting films have been widely utilized in photographic, LCD, electrical, and other diverse applications. 3,4 Meanwhile, in basic material science research, the solution casting method is a common method for obtaining various functional or structural films, attributed to its easy addition of auxiliary materials, easy operation, low equipment requirements, and low energy consumption.…”