Effect of bio-based polyols and chain extender on the microphase separation structure, mechanical properties and morphology of rigid polyurethane foams

The preparation of polyurethane foams from bio-based polyols was a preferable alternative to save fossil resources, and the investigation of the microphase separation structure of foams can effectively guide their application. In this work, rigid polyurethane (PU) foams from three bio-based polyols and different content of chain extender of 1,4-butanediol were prepared. Microphase separation behavior and thermodynamic properties of the foams were analyzed by ATR-FTIR, SEM, TG, DSC and DMA. The hydrogen bond content increases and the microphase separation tendency is suppressed with the addition of bio-based polyols. The TG analysis reveals that the thermal loss of bio-based foams is earlier than that of petroleum-based foams at the initial stage. The hydrogen bond content of bio-based rigid PU foam derived from corn stalks increases by 6.03 % relative to petroleum-based foam, and the compression strength reaches 160.18 KPa. Furthermore, with the addition of 1,4butanediol (5 wt%), the compression strength of bio-based rigid PU foam derived from corn stalks rises to 325.05 KPa, while the proportion of ordered hydrogen bonds is considerably higher than that of the original foam, demonstrating the increase in the degree of microphase separation.