Hydroxyl-Terminated Polybutadiene-Based Polyurethane with Self-Healing and Reprocessing Capabilities

Abstract

Hydroxyl-terminated polybutadiene (HTPB)-based polyurethane (PU) networks play indispensable roles in a variety of applications; however, they cannot be reprocessed, resulting in environmental problems and unsustainable industrial development. In this work, recyclable HTPB-based PU vitrimer (HTPB-PU V ) networks are fabricated by introduction of a cross-linker 2,2′-(1,4-phenylene)-bis[4-mercaptan-1,3,2-dioxaborolane] (BDB) with dynamic boronic ester bonds into the network. Meanwhile, the BDB can stabilize the HTPB unit in the network by elimination of double bonds. The novel HTPB-PU V networks are constructed by a thiol-ene “click” reaction and an addition reaction between HTPB and cross-linker BDB and isocyanates (HDI). The dynamic HTPB-PU V networks are characterized by dynamic mechanical analysis (DMA) and Fourier transform infrared (FTIR). The obtained dynamic HTPB-PU V networks possess superior thermostability. Moreover, due to the presence of dynamic boronic ester bonds, the HTPB-PU V network topologies can be altered, contributing to the reprocessing, self-healing, and welding abilities of the final polymer. Through a hot press, the pulverized sample can be reprocessed for several cycles, and mechanical properties of the reprocessed samples are similar to those of the pristine one, with the tensile strength being even higher. The self-healed sample exhibits almost complete recovery from scratch after the healing treatment at 130 °C for 3 h. Moreover, a welding efficiency of 120% was achieved.

Recent Developments in Shape Memory Elastomers for Biotechnology Applications

“…The phenomenon indicated that the internal segments in materials can rapidly respond to temperature changes and accelerate the recovery to their original shape [55]. Furthermore, another example by Li et al [86] confirmed the effect of temperature on the self-healing process of shape memory elastomers as shown in Figure 9. Hydroxyl-terminated polybutadiene (HTPB)-based polyurethane (PU) networks were prepared as the self-healing samples.…”

“…Hydroxyl-terminated polybutadiene (HTPB)-based polyurethane (PU) networks were prepared as the self-healing samples. They almost recovered from damage after the healing process at 130 °C for 3 h. Therefore, a fusing efficiency of 120% was reached [86]. Chen et al [55] presented the preparation of biomass bifunctional polyamide elastomers (BbPEs) from dimer acid (DA), trimer acid (TA), and triethylenetetramine to obtain a shape memory behaviour with self-healing characteristics.…”

“…Hydroxyl-terminated polybutadiene (HTPB)-based polyurethane (PU) networks were prepared as the self-healing samples. They almost recovered from damage after the healing process at 130 • C for 3 h. Therefore, a fusing efficiency of 120% was reached [86]. Furthermore, the indexes for quantifying the self-healing abilities were presented in Buaksuntear et al ( 2022) [87].…”

“…Self-healing of shape memory elastomer from HTPB-PU; (a) optical images of self-healing behaviour of HTPB-PUV, (b) recovery ratio of mechanical properties of HTPB-PUV fusing at 130 • Cfor different treating times of 0.5, 1.0, and 2.0 h, and (c) optical microscope images of before/after fusing and lap shear testing of HTPB-PUV[86]. Adapted with permission from[86]. Copyright 2022 American Chemical Society.…”

Malleable and self-healing rubbers covalently crosslinked by reversible boronic ester bonds

“…5(b), the relationship between the relaxation time and temperature of ENR@10PDA/B À was fitted according to the Arrhenius formula (shown in the ESI †), and the activation energy (E a ) of ENR@10PDA/B À was determined to be 35.1 kJ mol À1 , which is in the range (7.7-76.7 kJ mol À1 ) reported in the literature for polymers with boronic ester bonds. 44 In addition, the samples with a higher dopamine content exhibit a much slower relaxation rate and a longer relaxation time at the same temperature, as shown in Fig. S1 (ESI †).…”