New thermoplastic poly(carbonate-urethane)s based on diphenylethane derivative chain extender: The effect of diisocyanate structure on some properties.

Two series of new sulfur-containing thermoplastic poly(carbonate-urethane)s (PCURs) were prepared by a one-step melt polyaddition from diphenylethane derivative diol, i.e., 4,4′-(ethane-1,2-diyl)bis(benzenethiohexanol) as a nonconventional chain extender, 1,1′-methanediylbis(4-isocyanatobenzene) (MDI) or 1,6-diisocyanatohexane (HDI) and 20–60 mol% poly(hexane-1,6-diyl carbonate) diol of M ¯ n = 860 g mol−1 as a soft segment. The FTIR and XRD as well as DSC, TG, and TG coupled with FTIR were employed to characterize the PCURs' structure and thermal properties. Their physicochemical, adhesive, and tensile properties as well as Shore A/D hardness were also studied. The amorphous MDI-based PCURs were transparent materials (transmittance at 800 nm: 83–88%), while the HDI-based ones, showing partially crystalline structures (the degree of crystallinity: of 20–28%), were opaque. The polymers derived from HDI exhibited lower glass-transition temperatures than those obtained from MDI (from – 29 to – 12 °C vs. from 14 to 46 °C) as well as a higher degree of microphase separation. In turn, the PCURs based on MDI revealed higher tensile strength (up to 50.8 MPa vs. up to 33.4 MPa) and better thermal stability (e.g., the temperature of 1% mass loss: 294–305 °C vs. 262–278 °C). These sulfur-containing PCURs exhibited better adhesive properties to copper compared with the conventional PCURs synthesized from butane-1,4-diol as a chain extender. [ABSTRACT FROM AUTHOR]