Polyesters containing sulfur. VI. Synthesis and characterization of polyesters from naphthalene-1,4- or naphthalene-1,5-bis(methylthioacetic acid) and aliphatic diols
✍ Scribed by Anna Kultys; Wawrzyniec Podko⋅cielny; Stanisław Pikus
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 202 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0887-624X
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✦ Synopsis
Two series of new linear polyesters containing sulfur in the main chain were obtained by melt polycondensation of naphthalene-1,4-bis(methylthioacetic acid) (N-1,4-BMTAA) or naphthalene-1,5-bis(methylthioacetic acid) (N-1,5-BMTAA) with some aliphatic diols using a 0.05 molar excess of diol. Softening temperatures ranging from 55 to 130°C, reduced viscosities in the range of 0.15-0.39 dL/g, and low-molecular weights were their characteristic. The structure and thermal properties of all polyesters were examined by using elemental analysis, FT-IR and 1 H-NMR spectroscopy, X-ray diffraction analysis, differential thermal analysis (DTA), thermogravimetric analysis (TGA), and differential scanning calorymetry (DSC). The kinetics of polyester formation by uncatalyzed melt polycondensation was studied in a model system: N-1,4-BMTAA or N-1,5-BMTAA and 2,2Ј-oxydiethanol (ODE) at 150, 160, and 170°C. Reaction rate constants (k 3 ) and activation parameters (⌬G ‡ , ⌬H ‡ , ⌬S ‡ ) from carboxyl group loss were determined using classical kinetic methods. Hydroxyl-terminated polyesters derived from 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol were used for preparation of the polyurethanes by melt polyaddition with hexamethylene diisocyanate (HDI). They were characterized by reduced viscosity, FT-IR spectroscopy, X-ray diffraction analysis, TGA, DSC, polarizing microscope observation, and hardness and tensile properties. The resulting polyurethanes behave like high-elasticity thermoplastic elastomers, except the one derived from N-1,5-BMTAA and 1,6-hexanediol-based polyester.