Damping, thermal, and mechanical properties of polyurethane based on poly(tetramethylene glycol)/epoxy interpenetrating polymer networks: effects of composition and isocyanate index

A series of polyurethane (PU) samples based on poly(tetramethylene glycol)/epoxy resin (EP) graft interpenetrating polymer networks (IPNs) were prepared and their damping, thermal, and mechanical properties were systematically studied in terms of composition and the value of the PU isocyanate index (R). The damping properties and thermal stability measurements revealed that the formation of PU/EP IPN could improve not only the damping capacity but also the thermal stability. Meanwhile, mechanical tests showed that the tensile strengths of the IPNs decreased while their impact strengths increased with increasing PU content. The value of R also had significant impacts on the properties of the IPNs when the PU and EP ratio was fixed, which could be an effective means for manipulating the fabrication of PU/EP IPNs. The morphologies of the PU/EP IPNs were observed by SEM and AFM characterization and the relationship between the morphologies and properties is discussed. With the results in hand, the PU/EP IPNs hold promise for use in structural damping materials.