In this study, natural extracts of plant origin were used as anti-aging compounds of biodegradable polymers. Coffee (0.5–10 wt%), cocoa, or cinnamon extracts were added to the polylactide matrix. The obtained materials were subjected to an accelerated aging process (720, 1440, or 2160 h) at 45 °C and 70% relative humidity under continuous UV radiation. The effectiveness of the tested extracts was compared to a commercially available anti-aging compound, 2 wt% of butylated hydroxytoluene. Visual evaluation, scanning electron microscopy, melt flow rate, thermogravimetry, differential scanning calorimetry, tensile strength, and impact tensile tests were performed. We show that the use of smaller amounts of tested extracts is particularly advantageous, which do not adversely affect the properties of polylactide-based materials at low contents. At the same time, their effectiveness in stabilizing tested properties during the accelerated aging process is mostly comparable to or greater than the reference compound.

The aim of this work was to produce a composite based on the blend of polylactide and polycaprolactone and reinforced with flax fiber, intended for processing by injection molding, with improved mechanical and biodegradation properties as compared to neat polylactide (PLA) and polycaprolactone (PCL). The material was prepared by mixing PLA, PCL and flax fibers (about 5 mm long), extrusion and granulation with subsequent injection molding to obtain test samples. The composites differed in the content of PCL (0, 5, 10, 15 and 30 wt %) whereas the content of flax fibers was kept constant (20 wt %). The samples were characterized by means of scanning electron microscopy (SEM), tensile and impact strength measurements, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Biodegradation studies were carried out using proteinase K at laboratory conditions. It was found that a reduction of fiber lengths took place during the extrusion process and that addition of flax fibers to PLA/PCL blend resulted in an increase in elastic modulus and biodegradation rate. The composite impact strength was significantly improved at 30 wt % PCL fraction.

The paper presents the effects of biodegradation of polylactide containing natural anti-aging compounds. Polymer containing 0.5; 5 and 10 wt % of coffee, cocoa or cinnamon extracts were subjected to industrial composting for 7, 14, 21 or 28 days. The effect of the composting process on polylactide properties was examined based on visual assessment, scanning electron microscopy, average molecular weight, differential scanning calorimetry, thermogravimetry, and tensile strength. The impact of the tested extracts on the effects of the composting process was compared with the impact of a commercially available anti-aging compound. It was found that the tested extracts in most cases did not adversely affect the effects of the composting process compared to pure polylactide, often resulting in intensification of biodegradation processes. As a result of the composting process, changes in the macro- and microscopic appearance of the samples and a decrease in molecular weight, phase transition temperatures, thermal resistance, and thermal strength were observed on a scale close to or greater than the reference anti-aging compound.