Biodegradable Materials Composed of PLA and High Load Triglycerides

The ability of biodegradable polymers, such as polylactic acid (PLA), to incorporate high amounts of triglycerides (10–50 w/w%) and remain solid transparent films was examined for the changes in polymer mechanical and thermal properties as a part of developing new biodegradable safe materials. In this context, sesame oil was used as common safe natural mixture of triglycerides. PLA loaded with 50% w/w of sesame oil content formed uniform flexible and optical transparent films. To understand the microscopic structure, in particular the homo or heterogeneous distribution of oil in polymer, blends with 10%–50% sesame oil and other vegetable oils were evaluated by low-field Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimeter (DSC), X-ray photoelectron spectroscopy (XPS), X-ray Diffraction (XRD), and mechanical strength analysis. In addition to PLA, blends of polycaprolactone (PCL) with triglycerides were investigated as an alternative to an aliphatic polyester blend with lower glass transition temperature. On the molecular level, the data reveal a phase separation of oil and polymer in the PLA films with a close molecular interaction only occurring at the interface and a dispersion of the oil with immobilization by the polymer chains in the PCL films.