Comparative analysis of thermal degradation effects on traditional and low-emission flexible polyurethane foams

The degradation of different flexible polyurethane foams for molded application after thermal aging were compared. A reference sample using traditional higher emission additives and four samples of different composition using low-emission additives were compared. For the modified samples volatile organic compound (VOC) and semi-volatile organic compound (FOG/SVOC) contents fell well below the benchmarking limits, which indicates that the selected low-emission additives are incorporated into the polymer chain. To examine different material properties and for evaluating changes due to increased temperature exposure for a prolonged period of time mechanical and acoustic tests were carried out before and after dry heat aging. It was found that two low emission samples exhibited superior sound absorption compared to the reference sample along with less significant change after aging in the acoustic properties. The compressive strength was lower than the reference as a result of lower product densities. However, the change in compressive strength after aging was less than 15% (with one exception), which is acceptable according to the standard requirements. Thermogravimetric analysis was also performed and revealed that no significant difference can be observed between the examined samples due to heat degradation, indicating that the modifications made to reduce VOC content did not adversely affect the foam’s resistance to thermal degradation.