Enhancement of microphase ordering and mechanical properties of supramolecular hydrogen-bonded polyurethane networks

Abstract

Enhanced thermoreversible and mechanical properties in supramolecular polyurethanes have been realised by the incorporation of flexible DBDI derived hard segments.

Property enhancement of healable supramolecular polyurethanes

“…Furthermore, variable temperature FT-IR spectroscopic analysis was conducted on the SPU 1 and RSPUs ( Figure S27) and revealed a thermo-responsive behaviour similar to structurally related polyurethanes. [35,42,46,47] A strong absorbance for hydrogen bonded N-H absorbances was observed, centred at approximately 3320 cm -1 , arising from urethane and urea moieties. The intensity of the absorbance band (calculated by integration between 3400-3100 cm -1 ) was seen to diminish with increased temperature (20 °C -120 °C) for all polyurethanes as a result of dissociation of the hydrogen bonding interaction within the polymer network.…”

“…This is analogous to other approach reported in the literature in which hard segment content is increased through the incorporation of covalently bonded chain-extenders to enhance phase separation in polyurethanes. [33][34][35][36][37] Crucially, purification was not required to form the self-assembled polymer networks as the additive was formed in situ. The effect of increasing the weight percentage of the LMWA, and thus the relative hard domain content was studied systematically, and the material properties assessed.…”

Properties and degradation of castor oil-based fluoridated biopolyurethanes with different lengths of fluorinated segments

“…12,13 The incompatibility between so and hard segments leads to microphase separation, and the level of microphase separation is closely related to the tensile strength of PU. 14,15 Studies have discussed factors causing microphase separation in PU, such as hydrogen bonds (HBs) 16,17 and the ratio of so and hard segments. 18,19 Thermoplastic PU exhibits high strength, toughness, and wearability, and has properties of both plastics and elastomers; 20,21 thus it can be used in various industries.…”

Re-usable thermally reversible crosslinked adhesives from robust polyester and poly(ester urethane) Diels–Alder networks

“…It may also be feasible to incorporate other supramolecular functional groups which have low association constants since they also provide networks with interesting properties. [49][50][51][52] Thermal stability, reversibility and re-use of CANs Since adhesives must be stable during application and the maleimide functional group can be reactive towards radicals and nucleophiles, 29 we evaluated the thermal stability of the Diels-Alder CAN DA-4 at different temperatures (Fig. 7).…”