Influence of cell opener in high resilience molded polyurethane foam

In a chemical method for cell opening of high resilience (HR) molded polyurethane (PU) foam, two types of cell openers, the poly(ester-ether) type, PESE, having ester linkage and hydrophilic polyether segment in the molecule and the conventional polyether type, poly(propylene oxide-ethylene oxide), PPEO, were employed. The influence of structure and concentration of cell opener on the kinetics, stability, open cell content and mechanical properties of molded foam were investigated. The PESE-based formulation exhibited delayed reaction times and good stability compared to the PPEO-based formulation. The open cell content increased with cell opener amount and was independent of the cell opener structure. The mechanical properties clearly depend on the structure of cell opener. The PESE-based formulation had improved mechanical properties such as indentation hardness, tensile strength and tear strength. The increase of PPEO concentration significantly deteriorated the, molded foam's mechanical properties, while the foam with PESE gave less deterioration of mechanical properties up to a specific concentration of the PESE. With the above observations, PESE was found to be a useful cell opener for preparation of HR molded PU foam which has acceptable mechanical properties.