Polyesters containing sulfur. VII. New aliphatic-aromatic polyesters for synthesis of polyester-sulfur compositions and polyurethanes

✍ Scribed by Anna Kultys

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 289 KB
• Volume: 37
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19990315)37:6<835::aid-pola19>3.0.co;2-y

✦ Synopsis

New linear polyesters containing sulfur in the main chain were obtained by melt polycondensation of diphenylmethane-4,4Ј-bis(methylthioacetic acid) (DBMTAA) or diphenylmethane-4,4Ј-bis(methythiopropionic acid) (DBMTPA) and diphenylmethane-4,4Ј-bis(methylthioethanol) (DBMTE) at equimolar ratio of reagents (polyesters E-A and E-P) as well as at 0.15 molar excess of diol (polyesters E-A OH and E-P OH ).

The kinetics of these reactions was studied at 150, 160, and 170°C. Reaction rate constants (k 2 ) and activation parameters (⌬G , ⌬H , ⌬S ) from carboxyl group loss were determined using classical kinetic methods. E-A and E-P (M ¯n ϭ 4400, 4600) were used for synthesis of new rubber-like polyester-sulfur compositions, by heating with elemental sulfur, whereas oligoesterols E-A OH and E-P OH (M ¯n ϭ 2500, 2900) were converted to thermoplastic polyurethane elastomers by reaction with hexamethylene diisocyanate (HDI) or methylene bis(4-phenyl isocyanate) (MDI). The structure of the polymers was determined by elemental analysis, FT-IR and liquid or solid-state 1 H-, 13 C-NMR spectroscopy, and X-ray diffraction analysis. Thermal properties were measured by DTA, TGA, and DSC. Hardness and tensile properties of polyurethanes and polyester-sulfur compositions were also determined.