The Effect of Different Concentrations of Oyster Shell and Casein Powder on the Thermal Stability of Polyurethane

The call for environmental reforms has been increasing. prominent in the 21st century. Polyurethane foam, commonly found in buildings and household equipment, poses environmental risks, particularly when burned, as it can contribute to wildfire spread. To address this issue, scientists have explored bio-based flame retardants as protective measures. This project investigated the effectiveness of two bio-based flame retardants—casein and oyster shell—both independently and in combination. The hypothesis suggested that a synergistic combination of oyster shell and casein would prove more effective than either material alone or the control. This was based on the understanding that while higher oyster shell concentrations can decrease effect the tensile strength of polyurethane, combining it with casein could compensate for these effects while maintaining oyster shell's effective char layer formation. The experiment involved creating four intumescent flame retardants: casein alone, oyster shell alone, a combination of both, and a control. Statistical analysis using ANOVA with an α-value of 0.05 revealed significant differences between the experimental groups and the control (p-value < 0.001, α= 0.05). The post-hoc-tukey test, as well at the F=23.0 demonstrated significant differences between experimental groups, except between the combination and casein and casein and oyster. The hypothesis was partially supported, as significant differences were found between most groups, though the combination of casein and oyster shell did not show significant improvement over casein alone but did so over oyster shell alone. This research contributes to the understanding of bio-based flame retardants and their potential applications in environmental protection.