The effect of chain extender structure on the properties of new thermoplastic poly(carbonate–urethane)s derived from MDI

Abstract

Two series of high-molar-mass thermoplastic poly(carbonate-urethane)s (PCURs) were synthesized from nonconventional sulfur-containing chain extenders, i.e., 2,2 0 -[sulfanediylbis(benzene-1,4-diyloxy)]diethanol (diol SE) and 2,2 0 -[methanediylbis(benzene-1,4-diylmethanediylsulfanediyl)]diethanol (diol ME), 1,1 0 -methanediylbis(4-isocyanatobenzene) and 30, 45 and 60 mol% aliphatic polycarbonate diol of M n = 2000 g mol -1 (Desmophen Ò C2200, Bayer) via a one-step melt polyaddition. The PCURs were investigated by FTIR, UV-Vis, atomic force microscopy, X-ray diffraction analysis, differential scanning calorimetry, thermogravimetry (TG) and TG-FTIR. Moreover, their Shore A/D hardness, tensile, adhesive and optical properties were determined. The obtained PCURs were transparent or opaque elastomers, possessing amorphous or partially crystalline structures. The polymers based on diol ME showed lower glass transition temperatures (-9 to (-8) vs. -7 to 20°C) and better microphase separation. All the PCURs exhibited a relatively good thermal stability. Their temperature of 1 % mass loss was within the range of 284-292°C with somewhat higher values shown by those obtained from diol ME. The PCURs decomposed in two (from diol ME) or three (from diol SE) stages, and for both types of polymers, the main decomposition occurred at the first stage. All the PCURs based on diol SE exhibited higher tensile strength (33.5-41.9 vs. 27.0-31.5 MPa), but smaller elongation at break (300-400 vs. 450-550 %) than polymers derived from diol ME. Somewhat better adhesive properties and a slightly higher refractive index were found for polymer based on diol ME with two sulfur atoms.

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

“…However, with the increase in PHCD content, these differences became smaller. The PCURs of both series were characterized by similar or better thermal stability in comparison with the MDI-based PCURs prepared from other sulfurcontaining aliphatic-aromatic chain extenders [17,18] or aliphatic one [32,33].…”

“…Additionally, introducing bromine atoms into the structure of these diols results in improved flame retardancy of the resulting materials [12]. My co-workers' and my own scientific interests cover aliphatic-aromatic diols with sulfur atoms being the derivatives, among others, of diphenylmethane [13][14][15], diphenyl ether and diphenyl sulfide [16][17][18]. They allow to obtain thermoplastic polyurethanes with good thermal stability and mechanical properties, but at the same time with higher adhesive strength to metals and refractive index in comparison with a conventional aliphatic diol [18][19][20][21].…”

“…They allow to obtain thermoplastic polyurethanes with good thermal stability and mechanical properties, but at the same time with higher adhesive strength to metals and refractive index in comparison with a conventional aliphatic diol [18][19][20][21]. Although it is possible to prepare thermoplastic PCURs from the abovementioned sulfur-containing chain extenders with good performance characteristics, it is interesting to check whether the use of the chain extenders with symmetric and linear structure instead of those with an angled one [17,18] will improve the properties of obtained PCURs. The main aim of this work was to study the effect of diphenylethanederivative diols differing in the length of the aliphatic chain on the structure and thermal, mechanical, physicochemical and adhesive properties of new thermoplastic PCURs.…”

Structure analysis and thermal degradation characteristics of bio-based poly(propylene succinate)s obtained by using different catalyst amounts

“…The peaks at 1170 cm -1 on the glycol spectrum and at 1200 cm -1 on the succinic acid spectrum were also attributed to the stretching C-C-O group vibration but originating from hydroxyl and carboxyl groups, respectively [23]. 1 H NMR spectra were used to study the structure of the synthesised polyesters (Fig. 3).…”

“…Polyols constitute one of the major components for the polyurethanes synthesis [1]. They are usually liquid, reactive substances mostly terminated by the hydroxyl or partially amine groups [2], which are responsible for the reaction with isocyanates [3,4].…”