Polytetramethylene Ether Glycol Description:

Polytetramethylene ether glycol (PTMEG) is a waxy white solid that melts to a clear, colorless, viscous liquid near room temperature. PTMEG is produced by the catalytic polymerization of tetrahydrofuran (THF). The main applications of PTMEG are the production of spandex (polyurethane) fibers, polyurethane elastomers, and copolyester-ether elastomers.

Polytetramethylene Ether Glycol Instruction:

Polyurethanes are produced primarily from polyols and diisocyanates, where the polyol fraction (in this case, PTMEG) forms the soft segment and the diisocyanate provides the hard segment. PTMEG is used in thermoplastic polyurethanes (TPUs) and cast polyurethane elastomers, as well as polyurethane adhesives, sealants and surface coatings. Products made from PTMEG-based polyurethane elastomers include automotive and aviation hoses and gaskets, forklift tires and wheels, roller skate wheels, industrial belts, tank and pipe liners, mining and oil production pump liners, shoes (such as athletic shoes), apparel (such as leather coats), and medical prostheses, catheters and other medical devices. The advantages of PTMEG-based polyurethanes are resistance to hydrolysis and fungus, low-temperature flexibility, low heat buildup, high elasticity, low viscosity, and very low noise characteristics.

The most widely used method of making PTMEG is based on mixing tetrahydrofuran (THF) with fluorosulfonic acid (FSA) catalyst (HSO3F). In this reaction, the main polymerization products formed are polytetramethylene ether chains with sulfate groups. These sulfates are then hydrolyzed with water and the acid is removed. In the water extraction step, all water-soluble short polyether chains are also removed and the molecular weight distribution becomes narrower.

The newer PTMEG facilities use variations of the acetic anhydride process. In this type of process, the THF ring is opened by a strong acid catalyst and then reacted with acetic anhydride to form PTMEG diacetate, which is then converted to polyether diol by alcoholysis.