Publications

It is widely accepted that zinc oxide (ZnO) is the best activator for sulphur vulcanization of rubber composites. However, ZnO is recognized as a toxic substance for both human and aquatic organisms. Therefore, it is of great importance, but still challengeable to exploit eco-friendly alternatives to reduce ZnO, without comprising the performance of rubber composites. Herein, we describe a novel strategy to achieve substantial reduction of ZnO in diene-rubber composites, by utilizing carbon nanodots (CDs) as an efficient activator for sulphur vulcanization. With the substitution of CDs for ZnO, the cross-linking rate of the rubber composites remarkably accelerated, mainly due to the fact that the N-related moieties of CDs can facilitate the formation of sulphur-based networks via significantly reducing the activation energy of the cross-linking reactions. Moreover, the activation efficiency of the synthesized CDs was also confirmed in the rubber formulations filled with conventional fillers. We envisage that this strategy can provide a green and practical avenue towards the substantial pollution abatement from ZnO in rubber composites.

Rubbers are strategically important due to their indispensable applications in the daily life and high-tech fields. For their real-world applications, the covalent cross-linking, reinforcement, and malleability of rubbers are three important issues because they are closely related to the elasticity, mechanical properties, and recycling of the rubber materials. Herein, we demonstrate a simple way to prepare covalently cross-linked yet recyclable and robust elastomeric vitrimer composites by incorporating exchangeable β-hydroxyl ester bonds into the elastomer-nanoparticle interface using epoxy group-functionalized silica (Esilica) as both cross-linker and reinforcement in carboxyl group-grafted styrene-butadiene rubber (CSBR). The Esilica-cross-linked CSBR composites exhibit promising mechanical properties due to the covalent linkages in the interface and fine silica dispersion in the matrix. In addition, the interface can undergo dynamic reshuffling via transesterification reactions to alter network topology at high temperatures, conferring the resulting composites the ability to be reshaped and recycled.

Graphene oxide was directly reduced into graphene in N-methyl-pyrrolidone with the assisted-dispersion of vapor grown carbon nanofibers (VGCF), resulting in a homogeneous dispersion of VGCF–graphene hybrid filler (VGCF–G). In the hybrid filler, VGCF served as effective stabilizers for graphene by adsorbing VGCF onto graphene through π–π interaction. Subsequently, the as-prepared VGCF–G was incorporated into a bio-based polyester (BE) to prepare BE/VGCF–G composites by solution blending. In the composites, graphene was complete exfoliated with the assisted-dispersion of VGCF. Simultaneously, graphene acted as “compatibilizer” to improve the dispersion of VGCF and enhance the interfacial adhesions. As a consequence, the binary combination of VGCF and graphene showed remarkable synergistic effects in improving the electrical conductivity and mechanical properties of the BE/VGCF–G composites. For example, at the filler content of 4.8vol%, the electrical conductivity of BE/VGCF–G composite is about 4 orders of magnitude higher than BE/VGCF composite containing VGCF alone, and the ultimate stress and modulus of BE/VGCF–G composite is 58% and 45% higher than those for BE/VGCF composite. Furthermore, multi-stimuli responsive shape memory performances (electro-activated and infrared-triggered) of the composites were investigated. BE/VGCF–G composites showed a combination of higher shape memory recovery, stronger recovery stress and faster response, compared with BE/VGCF composites.

ABSTRACT To address the increasingly diverse demands in modern society, it is essential to develop multifunctional textiles that possess both thermoregulation and UV‐resistant properties. This study integrates coaxial and uniaxial electrospinning techniques to create multifunctional phase change nanofibers (PCNF) that exhibit high levels of hydrophobicity, ultraviolet (UV) resistance, and thermoregulation. During the coaxial electrospinning process, the thermal regulation of the nanofiber membrane is enhanced by incorporating octadecane into the core layer, resulting in a latent heat value of 82.47 J/g. Adding TiO 2 to the sheath layer significantly enhances the nanofibers' UV resistance, achieving a UV protection factor of 200.5. Furthermore, the inclusion of pearl‐like microspheres through uniaxial electrospinning significantly boosts the hydrophobicity of the PCNF, resulting in a water contact angle (WCA) of 148° and excellent stain‐resistant characteristics. This multifunctional composite membrane thus offers a highly promising solution for both outdoor protective applications and flexible wearable devices.

Nanostructured LiBH4 with greatly improved de-/hydrogenation thermodynamics and kinetics has been attracting the ever-growing interest for on-board hydrogen storage applications. However, it is challenging to controllably fabricate various nanostructures of LiBH4 due to its strong reducibility, high chemical activity and sensitivity to water and oxygen. Here, we demonstrate the very first success in tailoring the nanoscaled LiBH4 morphology from nanorods to nanoparticles by using few-layer graphenes (FL-Grs) as supporters. The presence of 30 wt% FL-Grs is optimal because it contributes not only substantial nucleation sites for LiBH4 nanoparticles but also sufficient catalytic activity for hydrogen storage in LiBH4. The resultant LiBH4-30 wt% FL-Grs displays 20–50 nm-sized particles in morphology, which enables the complete reversible storage of 7.2 wt% H2 starting from 230 ºC for desorption and 190 ºC for absorption along with a stable cyclability, greatly superior to pristine sample and even the nano-LiBH4/FL-Grs mixture. The somewhat particle growth as well as the segregation and isolation of B and LiH with cycling is reasonably responsible for the gradually slowed desorption/absorption kinetics. This important insight guides the design and development of nanostructured LiBH4-based composites featured high capacity and long life by combining nanometer size effect and catalytic effect.

The SiO2 insulating layer was prepared on the FeSiCr powders successfully by one-step dumping sol-gel method and ammonia was used as the catalyst. It is found that the growth of SiO2 layer can be tuned by the ammonia concentration. Within the reaction time of 0.5 h, SiO2 grows with heterogeneous nucleation when the ammonia concentration is 0.08–0.16 ml/g, and SiO2 coating layer was relatively uniform. With a high ammonia concentration of 0.20–0.24 ml/g, SiO2 grows with both heterogeneous and homogeneous nucleation, and SiO2 particles gathered and grew. The saturation magnetization and effective permeability of FeSiCr@SiO2 SMCs gradually decrease with the increase of ammonia concentration, while the specific resistance, quality factor and DC-bias property increase. With the ammonia concentration of 0.12 ml/g, the thickness of SiO2 insulating layer was about 30–60 nm. The annealed FeSiCr@SiO2 soft magnetic composite shows good soft magnetic performance with effective permeability and core loss of 45.52 and 418.32 kW/m3 at 0.05 T and 100 kHz, respectively, and the quality factor of 76.5 at 1 MHz.

To improve the antioxidative efficiency of 2-mercaptobenzimidazole (MB) and strengthen the interaction between halloysite nanotubes (HNTs) and natural rubber (NR), HNTs supported 2-mercaptobenzimidazole (HNTs-s-MB) was prepared by reacting MB with chlorosilane modified HNTs (m-HNTs). FTIR, XPS and TGA confirmed that MB was chemically bonded onto the surface of HNTs. HNTs-s-MB could be homogeneously dispersed in the NR matrix and there was a strong interfacial interaction between HNTs-s-MB and NR, leading to the better mechanical performances of NR/HNTs-s-MB nanocomposites than those of NR/HNTs nanocomposites. Based on the measurements of the thermo-oxidation activation energy of NR/HNTs-s-MB and NR/m-HNTs/MB nanocomposites containing equivalent antioxidant component, it was found that the antioxidative efficiency of HNTs-s-MB was superior to that of the corresponding low molecular MB owing to the much lower migration and volatility of HNTs-s-MB than those of MB.

Programming energy-dissipating units into polymers is an effective method to improve the toughness; however, the state-of-art approaches usually involve complicated chemistry manipulation and multistep process. In this contribution, we report a brand-new way to toughen styrene–butadiene rubber (SBR) by incorporating a sulfur-based ionomer to construct hierarchical coordination complexes. Specifically, the ionomer P(TA-S)/Fe containing polysulfide backbones and iron–carboxylate complexes was synthesized through the copolymerization of thioctic acid and sulfur, followed by introducing ferric chloride. Due to the reaction between polysulfide fragments in P(TA-S)/Fe and SBR, the incorporation of P(TA-S)/Fe enabled the chemical cross-linking of SBR and grafting of iron–carboxylate complexes onto SBR chains. The grafted iron–carboxylate complexes aggregated and formed a phase separate structure within SBR, which provided a multilevel energy-dissipating mechanism and consequently led to an integration of enhanced ultimate strength, modulus, and fracture toughness of SBR.

Front Cover: Inspired by the concept of the sacrificial bond, a strong yet sacrificial interface composed of metal-ligand coordination bonds is engineered in an elastomer/graphene composite. The strong interface ensures a high efficient stress transfer, meanwhile it is sacrificial during stretching, which dissipates enormous energy and facilitates rubber chain orientation. As a result, the composite exhibits a remarkable improvement in both strength and toughness. Further details can be found in the article by J. Huang, Z. Tang, Z. Yang, and B. Guo* on page 1040.