Environmentally-Friendly Synthesis of Carbonate-Type Macrodiols and Preparation of Transparent Self-Healable Thermoplastic Polyurethanes

Abstract

Carbonate-type macrodiols synthesized by base-catalyzed polycondensation of co-diols and dimethyl carbonate as an environmentally-friendly route were subsequently utilized for the preparation of transparent and self-healable thermoplastic polyurethanes (TPUs) containing a carbonate-type soft segment. Three types of macrodiols, obtained from mono, dual and triple diol-monomers for target molecular weights of 1 and 1.5 kg mol −1 , were analyzed by 1 H NMR integration and the OH titration value. Colorless transparent macrodiols in a liquid state at a room temperature of 20 • C were obtained, except the macrodiol from mono 1,6-hexanediol. Before TPU synthesis, macrodiols require pH neutralization to prevent gelation. TPUs synthesized by a solution pre-polymer method with 4,4 -methylene(bisphenyl isocyanate) and 1,4-butanediol as a chain extender exhibited moderate molecular weights, good transparencies and robust mechanical properties. Especially, the incorporation of 3-methyl-1,5-pentanediol within carbonate-type macrodiols enhanced the transparency of the resultant TPUs by decreasing the degree of microphase separation evidenced by ATR-FTIR and DSC. Interestingly, packing density of hard segments and the degree of microphase separation determined the self-healing efficiency of TPUs, which showed good performances in the case of sourced macrodiols from triple diol-monomers.

Mechano-responsive hydrogen-bonding array of thermoplastic polyurethane elastomer captures both strength and self-healing

“…The FT-IR spectrum of Es-MD shows an intense band at 1703 cm −1 that corresponds to H-bonded urethane groups in the hard domain (Supplementary Fig. 11 ), and conventional carbonate-type TPUs that contain MD also exhibit two dominant bands at approximately 1736 and 1699 cm −1 from their respective soft and hard domains 41 , 54 . On the contrary, the FT-IR spectrum of C-IP-SS shows four bands associated with carbonyl (C = O) groups (Fig.…”

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].…”

Mechano-responsive hydrogen-bonding array of thermoplastic polyurethane elastomer captures both strength and self-healing

“…1a and Supplementary Fig. 1) [39][40][41][42][43][44] . SS metathesis drives intrinsic self-healing at room temperature 45,46 .…”

“…The FT-IR spectrum of Es-MD shows an intense band at 1703 cm − 1 that corresponds to H-bonded urethane groups in the hard domain ( Supplementary Fig. 12), and conventional carbonate-type TPUs that contain MD also exhibit two dominant bands at approximately 1736 and 1699 cm − 1 from their respective soft and hard domains 41,50 .…”