Poly-G 55-112 Polyether diol Arch Chemicals Polyurethane (PU) - Polyols >> Polyether Coatings Polytetramethylene glycols (PTMG) are premium-priced polyether diols that are often used for "high performance" polyurethane elastomers when optimum physical properties and resistance to hydrolysis are required. PTMGs are also used when lesser properties are needed, which results in over-engineered products and unnecessary expense. Polyether diol. Used in coatings.