Tuning chain extender structure to prepare high-performance thermoplastic polyurethane elastomers

In this work, a novel strategy is developed to solve the issue of mutually exclusive high mechanical robustness and thermo-stability for thermoplastic polyurethane (PU). A leaf-like and reticulate interfingering superstructure can be seen. The superstructure of polyurethanes can also be tuned by the polarity of chain extender molecular via changing the number for ferrocene redox centres, thus to further enhance the thermal stability and elasticity of PUs. As a result, by incorporating bisferrocene units into the main chain of PU, a high-performance PU elastomer can be synthesized with a highest initial degradation temperature of T_5% of 345 °C, a highest tensile strength of 42.3 MPa with an elongation over 1000%, as well as a toughness of 19.6 GJ m⁻³. These results conclusively suggest that high-performance thermoplastic polyurethane elastomers had great promise for potential application in a wide range of practical fields.

Ester-containing ferrocenyl diols are introduced as chain extenders to tune the polyurethane superstructure to optimize thermo-stability and elasticity simultaneously.

Facile fabrication of polyurethane/epoxy IPNs filled graphene aerogel with improved damping, thermal and mechanical properties

In this article, polyurethane (PU)/epoxy (EP) interpenetrating polymer networks (IPNs) filled graphene aerogel (PEGA) was facilely fabricated by a one-step vacuum-assisted filling process. Effects of PU content on damping performance, thermal stability and mechanical properties of the PEGA composites were studied systematically. Results reveal that addition of graphene aerogel improves damping properties of PU/EP IPNs and increases the thermal decomposition temperature. Mechanical tests show that flexural strength, flexural modulus and Shore D hardness of the PEGA composites also improved by incorporation of graphene aerogel. The enhanced damping, thermal and mechanical properties of PEGA composites can be attributed to the uniform distribution of graphene sheets in the IPN matrix, which benefits from the three-dimensional interconnected porous network structure of the graphene aerogel used and good interfacial adhesion at the nanofiller-matrix interface. It is expected that the PEGA composites can be used as good structural damping materials in future.

PEGA composites were facilely fabricated by a one-step vacuum-assisted filling method, and exhibited improved damping, thermal and mechanical properties.

Facile fabrication of polyurethane-based graphene foam/lead zirconate titanate/polydimethylsiloxane composites with good damping performance

In modern society, much more noise and vibration are produced in traffic and industrial systems, which is harmful to human health, equipment safety and the environment, therefore damping materials are becoming increasingly important. A piezoelectric damping composite could broaden the damping temperature range and enhance the damping loss factor simultaneously by introducing a dissipation route of mechanical to electrical to heat energy. In this paper, a novel piezo-damping polyurethane-based graphene foam (PGF)/PZT/PDMS composite (PGPP) was facilely fabricated using a one-step vacuum-assisted filling method. Using three-dimensional graphene foam as a conductive phase, and due to its three-dimensional network structure, the PGPP composite can reach the percolation threshold with a dramatically reduced amount of RGO sheets. The effects of PZT content and frequency on the damping properties of the PGPP composites were investigated, and the results show that the storage modulus, loss modulus and loss factor of the PGPPs are all greatly enhanced compared to those of the PDMS matrix. Due to their flexibility, the PGPP composites can be used as good surface coating damping materials over a wide temperature range at different frequencies.

Using three-dimensional graphene foam as the conductive phase, the temperature range where tan δ > 0.3 for a piezo-damping PGPP composite is broadened to −70 to 100 °C.