Impact of Chain Extenders on Pore Structure, Properties, and Reaction Kinetics of Microporous Polyurethane Elastomers

The regulation of pore structure and its impact on the properties of microporous polyurethane elastomers (MPUEs) are crucial for various applications. This study investigated how different chain extenders, including diethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol, influenced the microphase separation, hydrogen bonding, pore morphology, and properties of MPUEs. The experimental results demonstrated that increasing the chain extender length enhanced hydrogen bonding and promoted microphase separation within the MPUEs. Concurrently, the gel reaction rate slowed, leading to corresponding changes in pore structure, which, in turn, affected the material’s damping and mechanical properties. Nonisothermal DSC and infrared expansion methods were employed to study the kinetics of polyurethane gel and foaming reactions. The kinetic analysis revealed that the pore structure could be effectively controlled by manipulating the gel reaction system. This study highlights the importance of achieving an optimal balance between gel and foaming reactions to produce MPUEs with desirable properties. The findings provide valuable insights into tailoring the microstructure of MPUEs for specific applications through the choice of chain extenders.