New thermoplastic poly(carbonate-urethane)s based on diphenylethane-derivative chain extenders\u2014the effect of chain extender structure on thermal and mechanical properties

Abstract

In this study, new thermoplastic sulfur-containing poly(carbonate-urethane)s (PCURs) were synthesized via a one-step melt polyaddition from diphenylethane-derivative diols with two or ten methylene groups in the aliphatic chain, i.e., 4,4′-(ethane-1,2-diyl)bis(benzenethioethanol) (diol E) and 4,4′-(ethane-1,2-diyl)bis(benzenethiodecanol) (diol D) as nonconventional chain extenders, 1,1′-methanediylbis(4-isocyanatobenzene) and 20–60 mol% poly(hexane-1,6-diyl carbonate) diol of overline{M}_{rm{n}} = 860 g mol−1 as a soft segment. The PCURs were studied mainly to describe their thermal and mechanical behaviors by means of DSC, TG and TG coupled with FTIR, and Shore hardness and tensile tests. Moreover, their structure and physicochemical and adhesive properties were determined. The results of the study showed that the kind of the chain extender as well as soft-segment content had an impact on the properties of the polymers obtained. They were amorphous or semicrystalline high molar mass materials. The PCURs based on diol D exhibited lower glass transition temperatures in comparison with those based on diol E with shorter aliphatic chain (− 1–24 °C vs. 13–55 °C). Unfortunately, the former polymers revealed somewhat poorer tensile strengths (up to 45.0 MPa vs. 51.8 MPa). Nevertheless, these values were similar to or higher than those obtained for their commercial analogs. The PCURs being diol D derivatives also showed, in general, lower hardness and the modulus of elasticity but higher elongation at break. All the PCURs exhibited a relatively good thermal stability. However, the polymers derived from diol D revealed higher temperatures of 1, 10 and 50% mass losses compared with diol E-based ones (290–298 °C vs. 285–287 °C, 325–336 °C vs. 314–323 °C, 360–381 °C vs. 348–356 °C, respectively). The newly synthesized sulfur-containing PCURs showed better adhesive properties to copper than the analogous polymer based on butane-1,4-diol as a chain extender.