It is still challenging and attractive to prepare polyurethane
(PU) materials with excellent self-healing ability while improving
their mechanical properties and high ductility. Here, a multifunctional
linear PU supramolecular elastomer was successfully prepared by introducing
a cross-linking network of quadruple hydrogen bonds and thermo-reversible
Diels–Alder bonds and rigid ring structure to the linear backbone.
The results exhibited that the obtained PU elastomer displayed a high
tensile strength (6.30 MPa), elongation (1957.84%), toughness (84.48
MJ/m3), and excellent repair efficiency (93.33%). The quadruple
hydrogen bonds from 5-(2-hydroxyethyl)-6-methyl-2-aminouracil and
thermo-reversible Diels–Alder bonds from the conjugated reaction
of 4,4′-bismaleimide diphenylmethane with furfuryl alcohol,
due to its synergetic dual reversible bonds, formed the PU elastomer
that possessed excellent mechanical, self-healing, shape recovery,
and reprocessing properties. The prepared multifunctional PU can be
used as a substrate for flexible conductive materials or as conductive
composite material with conductive materials, which can self-repair
many times when the surface is damaged, can be recycled, and greatly
improve the service life of the material. Therefore, the prepared
multifunctional high-performance self-healing PU materials have potential
applications in several fields.
Three-dimensional (3D) graphene oxide aerogel (GOA) is one of the best fillers for composites for microwave absorption. However, its further development has been hindered by the poor mechanical properties. Methodology to improve the mechanical properties of the aerogel remains an urgent challenge. Herein, graphene oxide/carbon nanotube/epoxy resin composite aerogel (GCEA) was successfully prepared by a facile method. The results showed that the prepared GCEA with the hierarchical and 3D cross-linked structures exhibited excellent compression performance, structural and thermal stability, high hydrophilicity, and microwave absorption. The prepared GCEA recovered from multiple large strain cycles without significant permanent deformation. The minimum reflection loss (RL) was −39.60 dB and the maximum effective absorption bandwidth (EAB) was 2.48 GHz. The development of the enhanced GO aerogels will offer a new approach to the preparation of 3D microwave-absorbing skeletal materials with good mechanical properties.
Graphene oxide aerogel (GOA) has wide application prospects due to its low density and high porosity. However, the poor mechanical properties and unstable structure of GOA have limited its practical applications. In this study, polyethyleneimide (PEI) was used to graft onto the surface of GO and carbon nanotubes (CNTs) to improve compatibility with polymers. Composite GOA was prepared by adding styrene-butadiene latex (SBL) to the modified GO and CNTs. The synergistic effect of PEI and SBL, resulted in an aerogel with excellent mechanical properties, compressive resistance, and structural stability. When the ratio of SBL to GO and GO to CNTs was 2:1 and 7:3, respectively, the obtained aerogel performance was the best, and the maximum compressive stress was 784.35% higher than that of GOA. The graft of PEI on the surface of GO and CNT could improve the mechanical properties of the aerogel, with greater improvements observed with grafting onto the surface of GO. Compared with GO/CNT/SBL aerogel without PEI grafting, the maximum stress of GO/CNT–PEI/SBL aerogel increased by 5.57%, that of GO–PEI/CNT/SBL aerogel increased by 20.25%, and that of GO–PEI/CNT–PEI/SBL aerogel increased by 28.99%. This work not only provided a possibility for the practical application of aerogel, but also steered the research of GOA in a new direction.
Dispersion of carbon nanomaterials in polymers has long been a challenge. In this work, large-scale epoxy-reinforced GO/CNT aerogel (GECA) was prepared with stable three-dimensional (3D) interconnected network as reinforced skeleton. The GECA/polystyrene (GECA/PS) nanocomposites were then fabricated by in-situ polymerization of styrene in interconnected GECA. The results showed that the obtained GECA exhibited high compression modulus with no significant permanent deformation. Furthermore, the mechanical properties of the prepared GECA/PS were significantly improved with a low filler content of 1.0 wt.%. when the ratio of GO and CNT to epoxy resin was 1:1, the tensile strength, flexural strength, compressive strength, and impact strength of the composites were the highest, at 17.51 MPa, 33.01 MPa, 110.28 MPa, and 4.169 KJ/m 2 , respectively, representing an increase of 113.0%, 76.1%, 147.5%, and 99.5%, respectively.
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