Publications

Upcycling of cross-linked rubbers is pressing. The introduction of dynamic covalent bonds into the networks is a popular tactic for recycling thermosetting polymers, but it is very challenging to integrate engineering performance and continuous yet stable reprocessability. Based on traditional rubber formulations, herein, a straightforward strategy is presented for constructing a skeletal network (SN) through interfacial crosslinking and percolation of rubbery granules in a rubber matrix. Rapid exchange reactions involving dynamic interfacial sulfides realize repeated "fragmentation and healing" in the solid-state and consequent reconfiguration of the SN topology of the elastomer, thus endowing the resultant SN elastomer with continuous yet stable re-extrudability. These SN elastomers with hierarchical structures exhibit high gel contents, high resilience, low creep, and reinforcibility competitive to traditional vulcanizates. Specifically, SN elastomers exhibit better overall performance than commercial thermoplastic vulcanizates (TPVs) materials. Overall, a new concept of thermoplastic vulcanizates is proposed, which will promote the sustainable development of rubbers.

Developing a catalyst for improving the efficiency of water electrolysis is one of the current research hotspots. Herein, we design and fabricate a nested-like Ce-doped CoP nanowires on carbon cloth. The Ce-CoP NWs/CC catalyst with optimized amounts of Ce-doping (6%) exhibits excellent hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance as well as preeminent overall water splitting (OWS) in alkaline media. As a high-performance and durable electrocatalyst, Ce-CoP NWs/CC presents low overpotentials with 80 and 290 mV at 10 mA cm -2 for HER and OER, outperforming many reported non-noble metal catalysts. Moreover, the assembled water-splitting device exhibits a voltage of only was also 1.506 V at 10 mA cm -2 . This work provides an efficient and inexpensive catalyst for overall water splitting.

Developing accurate and effective methods of dopamine (DA) detection is vital for the rapid diagnosis of diseases related to abnormal DA levels. Herein, we developed a high-performance, nonenzymatic dopamine electrochemical sensor for DA detection. The sensor was fabricated by synthesizing metal-oxide heterojunction porous nanofibers (PNFs), specifically cobalt-doped nickel oxide and gadolinium-doped cerium dioxide (Co-NiO/GDC), on a carbon nanofiber template using electrospinning and high-temperature annealing. The doping of Co²⁺ and Gd³⁺ was shown to induce lattice distortions in NiO and CeO₂, which in turn generated microstrains and surface defects at the phase interface. These structural enhancements played a key role in significantly boosting the material's catalytic activity for DA detection. The Co-NiO/GDC PNFs sensor demonstrated remarkable performance metrics, including a wide linear dynamic range (0.1 to 1100 μM), a high sensitivity (508.7 μA·mM^-1·cm^-2) and an exceptionally low detection limit (LOD = 0.018 μM, S/N = 3). The sensor also exhibited superior anti-interference properties, repeatability, reproducibility, and long-term stability. The sensor's practical utility was further validated by its ability to accurately detect DA levels in complex biological matrices such as animal serum and artificial urine, showcasing its potential for practical clinical applications.

Fully dense ceramic–carbon-nanotube composites with homogeneously distributed multiwalled carbon nanotubes (MWCNTs) (see Figure; inset shows a single MWCNT) have been synthesized by a unique method, which uses a polymer-derived ceramic as the composite matrix. Composites with an MWCNT fraction of 6.4 vol.-% had significantly increased Young's moduli, hardness, and damage resistance, compared to the values for the pure ceramic matrix.

Many recycled plastics are the polypropylene (PP)/poly(ethylene terephthalate) (PET) blends with PET as the minor component. The modification of such kinds of PP/PET blends for higher performance is essential as PP and PET are not thermodynamically compatible. In this study, the elastomer, SEBS‐ g ‐MAH, and the inorganics, halloysite nanotubes (HNTs) are chosen as the modifiers for the modification of a model PP/PET blend (90/10). The mechanical performance of such blend is optimized by the selective dispersion of the nanotubular HNTs into the interfacial region of the blends via a two‐step process. Compared with the control one, the overall mechanical properties of the blend are substantially improved. The crystallization of PP in the blend is also facilitated by the selective dispersion of HNTs and the folding surface free energy is substantially increased. The substantially improved mechanical performance is interpreted according to the formation of the unique morphology. This study provides new insight in improving the performance of polymer blends via selectively dispersing the nanosized inorganics in the blend. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Abstract Couplant is indispensable for ultrasound examinations. However, shape adaptability and operational feasibility, which are both crucial, cannot be provided conjointly by existing couplants due to their either liquid or solid form. Here an ideal couplant composed of fibers and dynamically cross‐linked polysilicone is reported, which exhibits a unique solid‐to‐fluid transition upon application of stress exceeding a threshold. Together with the acoustically transparent feature, the particularity of the stress‐triggered fluidity allows conformal adapting to arbitrary geometries under stress exertion and stable preserving for long‐term and reliable ultrasound examination after stress release. Steeply curved geometries and pressure‐sensitive tissues, which are extremely challenging for the state‐of‐the‐art ultrasound modalities, are successfully graphed or treated. This couplant integrates the merits of liquids and solids, providing new opportunities for various ultrasound in industrial and medical fields.

The development of an efficient and low-cost electrocatalyst is critical to the hydrogen evolution reaction (HER). Herein, we reported a Ru@Cr3N0.4C1.6 nanoparticles grown on carbon nanofibers, which was prepared by electrospinning and high temperature carbonization strategies. The introduction of Ru metal helps Cr3N0.4C1.6 nanoparticles expose active sites on the surface of CNF to improve the catalytic performance, while the introduction of Cr optimizes the binding energy of Ru-H to achieves higher catalytic activity. Moreover, the heterogeneous structure formed by Ru metal and Cr3N0.4C1.6 nanoparticles also contributed to the catalytic performance. Therefore, the Ru@Cr3N0.4C1.6/CNF exhibited excellent catalytic activity with a low overpotential of 35 mV to obtain current density of 10 mA cm−2 in 1 M KOH. And it also showed outstanding long-term stability after continuously working for 200 h. This work provides a new method to prepare catalysts efficiently and cheaply.

Layered inorganics are promising in the fabrication of elastomeric nanocomposites with enhanced barrier property. Recently, boehmite (BM) nanoplatelets have emerged as alternative layered inorganics to clays and double hydroxylates as the functional reinforcement for rubbers. In the present paper, natural tannic acid (TA) is introduced as a novel interfacial modifier in BM-filled styrene–butadiene rubber (SBR) nanocomposites. The modification mechanism and interfacial interactions in the nanocomposites are fully characterized. Due to the strengthened interface and the comparatively finer dispersion state of BM in the nanocomposites, significantly enhanced mechanical properties are found in the modified system. At higher BM loadings (higher than 40phr), the modified system possesses a much lower gas permeability compared with the unmodified counterpart. Very interestingly, the TA-modified SBR/BM nanocomposites exhibit high tensile strength yet impressively low moduli compared with previously reported rubber nanocomposites filled with other nanofillers.

The Ru–Fe 4 C/NCNF (Ru : Fe = 1 : 6) catalyst exhibits excellent catalytic performance ( η 10 = 106 mV and η 100 = 254 mV). The prepared catalyst can be used as a self-supporting working electrode and it shows excellent stability.

Recent progress in introducing elegant dynamic covalent bonds into covalently crosslinked networks enabled the trade-offs between chemical crosslinking and recycling. Thus far, continuous efforts are made to exploit new dynamic chemistries to address the constrains of intricate preparation procedures and need of catalyst additives in creating dynamic covalent networks. In this work, we report an industrially feasible process to prepare catalyst-free malleable elastomers by engineering dithioacetals as the dynamic motifs into a commercial diene rubber. Specifically, a dithioacetal-containing diacid (BTA) is synthesized and used as a novel crosslinker for epoxidized natural rubber (ENR), by which dynamic dithioacetals are introduced into the elastomeric networks. Small molecule model study shows that dithioacetal exchange can be conducted at elevated temperature without catalyst. In the BTA crosslinked ENR, the thermoactivated dithioacetal exchange reactions can alter its network topologies in an associative pathway and confer it with remarkable reprocessability. The mechanical properties and relaxation rate of the networks can be readily manipulated by varying the dithioacetal concentration.

Front Cover: Unlike the normal pristine MMT particles, which are compact and plane-shaped, these spray-dried pristine MMT particles display extraordinary flower-shaped morphologies. This indicates that the rapid evaporation process brought about by the spray-drying method achieves structures made of randomly arranged MMT layers in the granule. Further details can be found in the article by M. Lu, Y. Wang, Y. Wu, Y. Quan, X. Wu, L. Zhang,* and B. Guo on page 20.

The synergistic effect of dynamic covalent bond (DCB) multiplicity on the dynamic performance of vitrimeric elastomers is disclosed.

Carbon black (CB) is an irreplaceable filler in the rubber industry, due to its unparalleled cost performance. Nevertheless, the poor CB dispersion in the rubber matrix significantly compromises the overall performance of the composites, especially in the aspect of hysteresis loss. Herein, a novel adamantyl-based imine (DADI) was synthesized and then adopted as the interfacial mediator of natural rubber/CB composites. As demonstrated, the imine moieties on the DADI skeleton are capable of capturing the macroradicals generated by the scission of rubber chains during compounding, followed by stabilizing inside the adamantyl functionalities. These DADI-capped macroradicals can further transfer to the energy traps on the CB surface through electron cloud sharing, which enables strong interfacial adhesion between rubber matrix and CB and hence improves the dispersion state of CB particles. Consequently, with the incorporation of 1phr DADI, the resulting composite achieves remarkable decreases of approximately 6 °C in heat generation and 21% in energy loss. Besides, the aging resistance of the resulting samples is also considerably improved due to the capability of DADI to wipe out reactive radicals. We envisage that the synthetic DADI has great potential to prepare high-performance tire products in terms of low energy loss and superior aging resistance.

To introduce thiol–ene chemistry in the modification of composites by ionic liquid (IL), a novel functional IL, 1‐methylimidazolium mercaptopropionate (MimMP), was synthesized and investigated as a modifier for styrene–butadiene rubber/silica composites. MimMP could be hydrogen‐bonded with silica and react with the double bonds of rubber chains via thiol–ene chemistry. The filler networking, curing behavior, filler dispersion, crosslink density, and mechanical performance were fully studied. The filler networking in the uncured rubber compounds was effectively restrained. The vulcanization was largely accelerated by MimMP. The interfacial interaction was quantitatively evaluated and found to consistently increase with increasing MimMP. The mechanical performance and abrasion resistance of the modified vulcanizates improved considerably. The remarkable improvements were mainly ascribed to the improved interfacial structure comprised of MimMP–silica hydrogen bonding and MimMP–rubber covalent bonds via thiol–ene chemistry. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The development of advanced elastomers with a combination of high strength, large extensibility, and excellent flex-cracking resistance is a huge challenge. In this contribution, we proposed a novel strategy to engineer a multinetwork by incorporating weaker sacrificial hydrogen bonds and stronger Zn-based units into a chemically cross-linked cis-1,4-polyisoprene network. The dynamic nature allows the sacrificial bonds to be ruptured and re-formed, resulting in high stretchability. During external loading, the sacrificial bonds rupture prior to fracture of the covalent network, thus dissipating energy efficiently and facilitating chain orientation to produce improved tensile modulus and fracture toughness as well as significant enhancement of flex-cracking resistance. We propose that the enhanced cracking resistance may originate from the energy dissipation and re-forming of sacrificial bonds, a new mechanism alternative to strain-induced crystallization. Overall, this concept provides unique inspiration for the design of advanced elastomers with excellent mechanical properties under both static and dynamic conditions.

High-performance rubbers with low gas permeability have attracted extensive attention due to their wide application. In this work, for the first time, the tortuosity effect is created in unfilled rubbers via heterogeneous cross-linking. The heterogeneously cross-linked rubbers exhibit a sea–island morphology with excellent interfacial interactions in which the dispersed rubber granules (RGs) are densely cross-linked, while the matrix phase is normally cross-linked. The hard RG phases showed low gas permeability, which can not only serve as a rigid yet elastic reinforcement for rubbers but also inhibit the gas permeation in rubbers. The excellent interfacial interactions between the two phases have a pronounced effect on the ultimate performance of rubbers. Surprisingly, the simultaneously improved mechanical performance and the gas barrier property achieved in the heterogeneously cross-linked rubber are competitive with the rubber nanocomposites filled with two-dimensional fillers. It is revealed that the ingenuity of such a heterogeneous design is the tortuosity effect imposed by the dispersed RG phases with low permeability, which makes an additional contribution to the reduction of gas permeability. Accordingly, a modified Nielsen equation was developed to model the gas barrier property of heterogeneously cross-linked rubbers, offering reliable prediction and rational mechanism elucidation of gas permeation for the heterogeneous design. In view of the scale-up capability and universality of this method, we envisage that this work offers a promising avenue, alternative to nanofilling, for preparing the rubbers with excellent gas barrier properties.