Sorona polymer uses 1,3 propanediol (PDO) as the key base ingredient, along with other monomers and additives, to create a family of differentiated polymers. The unique properties of Sorona polymer – including softness, easy dyeability, comfort-stretch and recovery – were actually discovered and developed in the early 1940s. But for decades PDO was cost-prohibitive to produce due to several processing factors.