Polythiourethane Covalent Adaptable Networks for Strong and Reworkable Adhesives and Fully Recyclable Carbon Fiber-Reinforced Composites

Abstract

The development of adhesives with superior optical and mechanical performance, solvent resistance, and reworkability is gaining increasing attention in recent years. However, traditional materials do not possess reprocessability and healing characteristics for sustainable development. Here, a superior dynamic polythiourethane (PTU) adhesive with high reprocessability was developed by introducing covalent adaptable networks (CANs). Specifically, dynamic thiocarbamate bonds (TCB) were used to prepare PTU CANs, which showed dramatically enhanced malleability and recyclability. The Young’s modulus of the material was 2.0 GPa and the tensile strength was 62.7 MPa. The reprocessing temperature of CANs was reduced to 80 °C while more than 90% of their mechanical properties were retained, even after being reprocessed several times. Moreover, the highly transparent and water-resistant PTU CANs featured an excellent bonding property and reworkability for various materials including glass, with a lap shear strength of 2.9 MPa, metal (5.1 MPa), and wood (6.3 MPa), compared with commercially available adhesives. Additionally, carbon fiber-reinforced composites constructed with PTU CANs were capable of being fully recycled and reused. Importantly, laminated glass with a toughened PTU–PU elastomer interface exhibited an outstanding impact fatigue-resistance behavior, sustaining thousands of impacts. These features demonstrate that PTU CANs show great potential as sustainable materials.

Preparation of Fucoidan-Based Electrospun Nanofibers and Their Interaction With Endothelial Cells

“…Besides the biochemical properties, their biophysical structure can significantly mediate cell attachment, shape, viability, the differentiation or pluripotency of stem cells, and even tissue repair and regeneration ( Li et al, 2018 ; Cui et al, 2020 ; Yu et al, 2020 ; Yu et al, 2021 ; Zhou et al, 2020 ; Liu et al, 2021 ; Yang et al, 2021a ; Yang et al, 2021b ). Recently, the development of nanofibrous materials has received increasing attention in tissue engineering and regenerative medicine due to their outstanding properties, such as their favorable biological properties, sufficient mechanical strength, highly porous mesh with interconnectivity, extremely high specific surface area, and aspect ratio ( Zhou et al, 2015 ; Zhou et al, 2017 ; Kenry and Lim, 2017 ; Xue et al, 2019 ; Ahmadi et al, 2021 ).…”

A Strong and Rigid Coordination Adaptable Network that Can Be Reprocessed and Recycled at Mild Conditions

“…Such a recycling method has apparent advantages in less energy consumption, high recycling efficiency, and products maintaining the original high quality. 73,74 Page 23 of 37 CCS Chemistry…”

Matrix and Filler Recycling of Carbon and Glass Fiber-Reinforced Polymer Composites: A Review

“…Information on the recyclable systems and methodologies is presented in Table 4, while available values for several thermal and mechanical parameters of reviewed composites are presented in Table 5. Composite can be fully recycled, retains ILSS [93] The column identified by the recycling symbol (…”

“…Thermosets with reversible networks that can be de-crosslinked in an excess of monomers or comonomers might be suitable for primary recycling, since the obtained oligomeric solution can be corrected in terms of monomers and curing agent concentration and then reused. In terms of thermal properties, most of the discussed thermoset FRPs show Tg lower than 200 °C, some with values around room temperature [85,88,93], which would greatly limit their application, since thermosets used in high-performance FRPs are characterized by high Tg, around or higher than 200 °C [92]. Nonetheless, some of the works report values of Tg that are relatively high (170 °C) and also higher than 200 °C [81,87,89,91,94].…”

“…In particular, hydrolysable chemistries might be susceptible to fast weathering, which would greatly hinder their applications. The loss of a chemically stable In terms of thermal properties, most of the discussed thermoset FRPs show T g lower than 200 • C, some with values around room temperature [85,88,93], which would greatly limit their application, since thermosets used in high-performance FRPs are characterized by high T g , around or higher than 200 • C [92]. Nonetheless, some of the works report values of T g that are relatively high (170 • C) and also higher than 200 • C [81,87,89,91,94].…”