Thermoplastic Polyurethane

Poly(dimethylsiloxane) (PDMS) / poly(hexamethylene oxide) (PHMO)-based thermoplastic polyurethane (TPU) nanocomposite was investigated for potential use in biomedical application. Studies on the in vitro fatigue behaviour of the TPU and TPU nanocomposite (under physiological saline solution, 37°C conditions) were highlighted in this article. The data were compared with those of commercially available silicone elastomer (Nusil MED 4860). Results indicated that the TPU nanocomposite (2MED-C (2HM)) had greater fatigue properties than the virgin TPU, which provide strong evidence of its greater capacity to withstand cyclic forces than the host TPU when exposed to physiological fluid. This was caused by the presence of well dispersed and impermeable organofluoromica platelets in the TPU matrix resulted in more tortuous path for the physiological fluid diffusion, thereby decreasing the fluid permeability of the polymer. Eventhough the silicone elastomer has lesser hysteresis than the virgin TPU and TPU nanocomposite, its fatigue strength is much lower than those of the TPU nanocomposite. The findings revealed the potential of PDMS/PHMO based TPU nanocomposite to replace silicone elastomer as biomaterial, particularly for implantable biomedical device application.

The polyurea elastomer coating / lining technology has shown some very significant inroads since the introduction of the technology back in the late 1980’s. Initially, the polyurea technology had set itself in a different class of coating / lining systems as compared to conventional urethane coating / lining systems. This has been primarily due to the unique characteristics of the technology, both in processing and performance. However; over the years there has been a melding of the various technologies, and many have now classified or implied that polyureas are the same as urethane and/or urethane/urea systems. There is now a new class of polyurea systems that have different processing characteristics and some feel that these are not polyurea systems at all. “They can’t be” people say since you don’t need the high-pressure plural component processing equipment for application. This has led to some reluctance on the part of engineers and specifiers to confidently specify polyurea sy...