polytetramethylene

Polytetramethylene refers to a class of polyethers whose repeating unit is -O-(CH2)4-, giving poly(tetramethylene oxide) or poly(tetramethylene ether glycol) (PTMEG). In this context, polytetramethylene is a polyether diol with hydroxyl end groups, commonly used as a soft segment in polyurethane systems. The material is often described by its molecular weight, which can range from about 650 to several thousand g/mol, producing variants suitable for different polyurethane applications.

Production of polytetramethylene typically involves cationic ring-opening polymerization of tetrahydrofuran (THF) using Lewis acid catalysts, followed by end-group capping to yield diol functionality. The resulting polymer is colorless and can exist as a viscous liquid or a waxy solid depending on molecular weight. It has a low glass transition temperature, which contributes to excellent low-temperature flexibility and resilience in polyurethane formulations. The ether linkages confer good hydrolytic stability and chemical compatibility with diisocyanates, alcohols, and many solvents.

Applications of polytetramethylene include its role as a polyether soft segment in polyurethane elastomers, foams, coatings, and adhesives. It is also a primary component in the production of spandex (lycra) fibers, where PTMEG is reacted with diisocyanates and chain extenders to form segmented polyurethane networks that combine elasticity with strength. The material’s combination of flexibility, resilience, and processability makes it a common choice in flexible foams, coatings, and elastomeric products.

Safety and handling follow standard chemical-polymer guidelines; polytetramethylene is generally handled as a high molecular weight polyether diol and subjected to appropriate storage and occupational hygiene practices.