Waterborne polyurethane elastomer using renewable polyols

A series of waterborne polyurethane (WPU) elastomers were synthesized from isophorone diisocyanate, polycaprolactone diol (PCL), 1,3-propanediol produced from a glucose fermentation process (Bio-PDO), 1,4-butanediol, and dimethylolbutanoic acid as a function of Bio-PDO/PCL composition. With the addition and increasing amount of Bio-PDO, particle size of dispersion, hardness, water swelling, initial modulus, and stress at break decreased, while contact angle with the water drop of the dispersion cast film increased. The PCL WPU showed a single-step thermal degradation at about 370°C, while those of Bio-PDO-containing WPUs showed two step degradations at about 350 and 400°C suggesting the soft segment–hard segment phase separation.