Polyurethane was first developed as a replacement for rubber at the beginning of World War II. Because it was a versatile substitute for scarce materials the applications for this new organic polymer increased rapidly. This trend remains evident today, as processing techniques continue to be developed, and new formulations and additives created, polyurethanes can be found in virtually everything we encounter. From apparel to appliances, marine to medical, polyurethanes are used to create cost-effective, comfortable, supportive and long-lasting industrial and consumer products.

The nature of the underlying chemistry allows polyurethanes to be adapted to solve many challenging problems. Consequently, production of all types of polyurethanes is greatly expanding worldwide with customers like INEOS, Evonik, BASF, Wanhua and Indorama. With this growth, measurement and control are more important than ever in meeting business production goals. Many aspects of polyurethane production can be measured using near-infrared (NIR) spectroscopy including the measurement of OH number of polyols. When considering final product measurements, polyurethanes can really be considered to be an amide or an ester of carbonic acid (carbamate). The use of remote spectroscopic measurement methods provides analyses in real-time and minimizes the need for performing laboratory measurements. These methods can be applied in reactor systems for control of important properties during the reaction and to determine the endpoint of the reaction thus adding to the value and cost savings. The application note, “Measurements in Polyurethanes” describes the potential uses of Guided Wave hardware and software tools for key measurements in polyurethane production using fiber optic-based NIR spectroscopy.

Types of Polyurethane:

• Flexible polyurethane foam
• Rigid polyurethane foam
• Coatings, adhesives, sealants and elastomers (CASE)
• Thermoplastic polyurethane (TPU)
• Reaction Injection Molding (RIM)
• Binders
• Waterborne polyurethane dispersion (PUDs)