Synthesis and characterization of soft polyurethane for pressure ulcer prevention

Abstract

A series of super-soft polyurethanes was prepared by synthesizing lightly crosslinked polyurethane with low isocyanate:hydroxyl ([NCO]:[OH]) molar ratios. The starting materials were polymeric isocyanate (pMDI), polypropylene glycol (PPG), and 1,1,1-tris(hydroxymethyl)propane (TMP). The effects of the [NCO]:[OH] molar ratio and concentrations of the crosslinking agent TMP on the crosslink density and the thermal, dynamic-mechanical, and mechanical properties of the polyurethanes were determined. In addition, TMP generates chemical and physical crosslinks within polyurethane; therefore, data calculated using the Flory-Rehner equation and the rubber elasticity were compared. The success of the reaction between pMDI and PPG was confirmed using Fourier-transform infrared spectroscopy. The synthesized polyurethanes exhibited a mixing phase between soft and hard segments. The addition of TMP increased the crosslinking density, resulting in increased glass transition temperature, tensile properties, and hardness; however, the pressure distribution was suppressed. The synthesized polyurethane showed effective properties for pressure ulcer relief applications.

Keywords

• Polyurethane
• Pressure ulcer prevention
• Dynamic mechanical analysis