Zanieczyszczenie tworzywami, w tym mikroplastikami, stanowi problem wielu środowisk. W celu opracowania bioproduktu wytypowano mikroorganizmy przyspieszające biodegradację polilaktydu (PLA). Spośród 48 wybrano 6 szczepów bakterii, których aktywność metaboliczna istotnie wzrastała w obecności PLA, powodując zmiany degradacyjne folii. Dodatkowo nie wykazywały one fitotoksyczności wobec rzepaku.
EN
Of the 48 types of bacteria tested for their ability to grow on polylactide (PLA) film, 6 were selected whose metabolic activity significantly increased in the presence of PLA. After 28 days of incubation at 29°C, the growth was assessed according to the degree of surface coverage of the film sample, then the changes in the surface structure were analyzed and the BOD was detd. The mass loss of the PLA sample, carbonyl index and O/C ratio were detd. The anal. of PLA degradation changes indicated the greatest potential of bacterial strains isolated from polymer plastic waste from landfills. Additionally, they did not show phytotoxicity to rapeseed.
Co-rotating twin-screw extrusion is an energy consuming process that is generally not fully optimised to a specific polymer. From the point of view of the efficiency of the extrusion process, the starting material should be characterised by small grain sizes in comparison to the screw channel area, small surface area to volume ratio and small internal friction between the pellets. To develop a model describing the effect of polylactide (PLA) grain size on the extrusion efficiency, a series of experiments with a twin-screw extruder were carried out during which the energy consumption; torque on shafts and temperature of the melt on the extruder die were monitored. As feed material, both the neat PLA with different grain sizes and the PLA with expandable graphite fillers and phosphorous-based flame retardants were used. Morphology and dispersion quality of the composites were examined using scanning electron microscopy (SEM); flammability, smoke production, mass loss and heat release rates were tested using cone calorimetry; and melt flow rate was determine using a plastometer. Moreover, the thermal properties of the obtained composites were determined using differential scanning calorimetry (DSC). The results show that the choice of the starting material affects both the efficiency of the extrusion process and the flame retardancy properties of the composite materials.
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