DaKS - University of Kassel's research data repository

Poly(lactic acid) (PLA) is one of the most important bioplastics with good mechanical properties and reduced environmental impact compared to petro-based plastics. In order to improve both sustainability and cost-efficiency, PLA can be filled with low-cost particles, such as native potato starch. However, during processing in a twin-screw extruder, PLA and starch are prone to thermal, hydrolytic, and mechanical degradation, which can deteriorate composite properties. This dataset systematically describes how key compounding parameters including screw speed and configuration, temperature profile and PLA pre-drying time influence the properties of PLA-starch composites containing 50 wt.% native potato starch. Various analytical methods were used to characterize the properties (Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Melt Volume Rate (MVR), Scanning Electron Microscopy (SEM), color measurements). The results show that thermal properties remain largely unaffected by the chosen compounding parameters. In contrast, significant changes are observed in thermal stability, viscosity, color, and morphological structure with changes in process parameters. Higher screw speeds and temperatures increase thermomechanical stress, leading to a higher MVR value, indicating lower molecular weight. Color measurements reveal significant discoloration due to starch degradation and PLA chain scission, which correlate with increasing yellow and red tones and a decrease in brightness at higher thermomechanical stress due to elevated screw speed and temperatures. Overall, the data emphasizes the complex interactions between process parameters, in particular screw speed and temperature profile as well as the physicochemical properties of PLA-starch composites, providing valuable insights for the design of the compounding process in order to prevent pre-damage to the composites.
IMPORTANT: In case you use the data please cite our corresponding article.

This study investigates the thermo- and photo-oxidative degradation behavior of a bio-based polyamide (PA) 5.10, both neat and 20 wt.% regenerated cellulose fiber-reinforced (RCF). In addition, these materials were modified with two different UV stabilizers, AddWorks IBC760 (IBC), a hindered amine light stabilizer, and LUBIO UV16 (LUBIO), an UV absorber. 168 hours of storage at temperatures of 23 °C, 50 °C, 70 °C to 90 °C at 50 %rH, with and without UV exposure of 1000 W/m², revealed significant degradation effects both in neat and LUBIO-stabilized batches, including molecular chain splitting processes, embrittlement, reduction in surface polarity and pronounced yellowing. In contrast, the IBC provided superior stabilization, maintaining thermal and mechanical properties as well as color stability. RCF-reinforced PA 5.10 exhibited moisture-induced plasticization, increasing ductility as well as aging-induced embrittlement at elevated temperatures. SEM imaging confirmed an increased share of fiber ruptures in the UV exposed neat RCF-composites, while IBC-stabilized specimens preserved the high amount of fiber pull-outs. Melt volume rate measurements demonstrate the reduction in molecular weight due to the thermo- and photo-oxidative degradation. A linear polynomial regression was also used to demonstrate the characteristic degradation mechanisms of polyamide. Overall, the IBC-stabilized batches show a significant stabilization effect across all tested storage conditions. These findings highlight the potential of UV-stabilized RCF-reinforced PA 5.10 composites as sustainable replacements for petro-based polyamide composites in applications requiring long-term resistance to thermo- and photo-oxidative stress.

This data set consists of the measured data from the conducted experiments as well as the data analysis.
In case you use the data please cite the corresponding article. The corresponding publication is currently in publication process.