korean scientists have developed tpu with a bio-based content of up to 97%

scientists at the gyeongbuk institute of science and technology in daegu, south korea, have found a way to make thermoplastic polyurethane (tpu) with a bio-based content of 97%. it is made using biomass monomers instead of petroleum-based materials.

this tpu is made from sebacic acid polyester polyol, 1,4-butanediol and isocyanate using a one-shot polymerization process. sebacic acid is a fatty acid isolated from castor oil. for comparison, they tried reactions with bio-based aliphatic pentamethylene diisocyanate (pdi) and petroleum-based mdi, as well as combinations of the two.

tpu made using bio-based pdi has an average molecular weight of about 120,000 g/mol, a tensile strength of 20 mpa, and a tensile elongation of 587%. these properties are comparable to fossil-based tpus, the research team said. complex viscosity, tensile strength and strain all increase with increasing mdi content. they say it is possible to make tpu that is completely bio-based.

these materials have potential applications such as industrial sheets, screen protectors, bags, footwear, artificial leather and other apparel textiles. this r&d work was supported by the korean ministry of trade, industry and energy as part of its material component technology development project.