New thermoplastic nonsegmented thiopolyurethanes were obtained from the low-melting aliphatic-aromatic thiodiols 4,4'-bis(2-hydroxyethylthiomethyl)benzophenone (BHEB), 4,4'-bis(3-hydroxypropylthiomethyl)benzophenone (BHPB), and 4,4'-bis(6-hydroxyhexylthiomethyl)benzenophenone(BHHB) as well as hexamethylene diisocyanate (HDI), both by melt and solution polymerization with dibutyltin dilaurate as the catalyst. The effect of various solvents on molecular-weight values was examined. The polymers with the highest reduced viscosities (0.63-0.88 dL/g) were obtained when the polymerization was carried out in a solution of tetrachloroethane, N,N-dimethylacetamide, and N,N-dimethylacetamide or N,N-dimethylformamide for BHEB-, BHPB-, and BHHB-derived polyurethanes, respectively. These polymers with a partially crystalline structure showed glass-transition temperatures (T-g) in the range of -1 to 39 degrees C, melting temperatures (T-m) in the range of 107 to 124 degrees C, and thermal stabilities up to 230 to 240 degrees C. The BHEB-derived polyurethane is a low-elasticity material with high tensile strength (ca. 50 MPa), whereas the BHPB- and BHHB-derived polyurethanes are more elastic, showing yield stress at approximately 16 MPa. We also obtained segmented polyurethanes by using BHHB, HDI, and 20 to 80 mol % poly(oxytetramethylene) glycol (PTMG) of (M) over bar(n) = 1000 as the soft segment. These are high-molecular thermoplastic elastomers that show a partially crystalline structure. Thermal properties were investigated by thermogravimetric analysis and differential scanning calorimetry. The increase in PTMG content decreases the definite T-g and increases the solubility of the polymers. These segmented polyurethanes exhibit the definite T-g (-67 to -62 degrees C) nearly independent of the hard-segment content up to approximately 50 wt %, indicating the existence of mainly phase-separated son and hard segments. Shore A/D hardness and tensile properties were also determined. As the PTMG content increases, the hardness, modulus of elasticity, and tensile strength decrease, whereas elongation at break increases. (C) 1999 John Wiley & Sons, Inc.
