New segmented poly(ester-urethane)s from renewable resources

The physical and mechanical properties of aliphatic homopolyesters from monomers obtainable from renewable resources, namely, 1,3-propanediol and succinic acid, were improved by their combination with aromatic urethane segments capable of establishing strong intermolecular hydrogen bonds. Segmented poly(ester-urethane)s were synthesized from dihydroxy-terminated oligo(propylene succinate)s chain-extended with 4,4'-diisophenylmethane diisocyanate. The newly synthesized materials were exhaustively characterized by H-1 NMR spectroscopy, size exclusion chromatography, differential scanning calorimetry, dynamic mechanical analysis, and with respect to their main static mechanical properties, an Instron apparatus was used. The average repeat number of the hard segments, evaluated by NMR, ranged from 4 to 9, whereas that of the flexible segments was about 14. The degree of crystallinity, glass-transition temperature, melting point, tensile strength, elongation, and Young's modulus were influenced by the ratio between hard and soft segments of the segmented copolymer in a predictable way. The results demonstrated that poly(ester-urethane)s from 1,3-propanediol and succinic acid are promising thermoplastics. (C) 2001 John Wiley & Sons, Inc.