Influence of the soft segment length on the properties of water-cured poly(carbonate-urethane-urea)s

Poly(carbonate-urethane-urea)s (PCUU) based on oligocarbonate diols (M-n approximate to 2000) with different length of the hydrocarbon chain as soft segments were synthesized and investigated. Carbonate oligomerols were obtained in a two-step method from dimethyl carbonate (DMC) and linear ,-diols (1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-dekanediol and 1,12-dodecanediol). Oligo(trimethylene carbonate) diol was synthesized using ring-opening polymerization of trimethylence carbonate. PCUUs were obtained by prepolymer method using isophorone diisocyanate (IPDI) and water as a chain extender. Changes in polymers properties with increase of methylene group number between carbonate linkages were investigated by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), tensile strength and hardness measurements. The thermal stability was also analyzed by means of thermogravimetric analysis (TGA). Based on FTIR analysis influence of methylene groups number between carbonate linkages on phase separation and concentration of allophanate and biuret groups in the samples were investigated. The obtained poly(carbonate-urethane-urea)s exhibited very good mechanical properties. Tensile strength and elongation at break were 40MPa and 400-600%, respectively, depending on the oligocarbonate used. Copyright (c) 2014 John Wiley & Sons, Ltd.