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This study describes the synthesis of a hydroxyl silane coupling agent (HO-silane) through a click reaction between -SH in 3-(trimethoxysilyl) propane-1-thiol (KH-590) and -C=C- in 2-hydroxyethyl methacrylate (HEMA). This coupling agent was subsequently employed in the synthesis of silane-modified polyurethane (SPU) resin which could be moisture-cured at room temperature. The influence of r values (the molar ratio of --NCO and --OH) on the characteristics of SPU resins was investigated. These results reveal that an increase in the r value leads to a reduction in viscosity from 4.9 * [10.sup.5] to 1.9 * [10.sup.5] mPa*s, a rise in tensile strength from 0.88 to 0.98 Mpa followed by a decline to 0.69 MPa, and a reduction in extension at fracture from 236% to 94%. A SPU resin with a viscosity of approximately 3.6 * [10.sup.5] mPas, tensile strength of 0.98 MPa, and elongation at break of 218% can be produced when the r value is 1.8. In addition, a silane-modified polyurethane (MS) sealant with a tensile strength of 1.6 MPa in addition to elongation at break at 336% could be produced using the aforementioned SPU resin. KEYWORDS click reaction, hydroxy silane coupling agent, moisture-cured, sealant, silane-modified polyurethane, 1 | INTRODUCTION Polyurethane possesses exceptional qualities such as remarkable high elasticity, low-temperature flexibility, superior wear resistance, and impressive mechanical strength, thereby being extensively utilized in numerous fields including construction, [...]

Structural adhesives that do not require heating are in high demand in the automotive and electronics industries. However, it remains a challenge to develop robust adhesives that rapidly achieve super adhesion near ambient temperature. Herein, a room‐temperature curable, fast‐bonding, and super strong epoxy‐based structural adhesive was designed from the perspective of cross‐scale structure, which lies in threefold pivotal aspects: (i) high branching topology of glycerol carbonate‐capped polyurethane (PUGC) increases the kinetics of the ring‐opening reaction, contributing to fast crosslinking and the formation of abundant urethane and hydroxyl moieties; (ii) asynchronous crosslinking of epoxy and PUGC synergistically induces phase separation of PUGC within the epoxy resin and the resulting PUGC domains surrounded by interpenetrated shell serves to efficiently toughen the matrix; (iii) abundant dynamic hydrogen bonds including urethane and hydroxyl moieties, along with the elastomeric PUGC domains, dissipate energy of shearing force. As a result, the adhesive strength rapidly grows to 16 MPa within 4 hours, leveling off to 21 MPa after 7 hours, substantially outperforming commercial room‐temperature curable epoxy adhesives. The results of this study could advance the field of high‐performance adhesives and provide valuable insights into designing materials for efficient curing at room temperature. [ABSTRACT FROM AUTHOR]

The electrochemical CO2 reduction reaction (CO2RR) has received widespread attention as a promising method for producing sustainable chemicals and mitigating the global warming. Here, we demonstrate a general and facile synthetic route for the metal-nitrogen-carbon (M-N-C) type catalyst by simply calcinating metal acetate and urea with commercial carbon black, which have potential application in CO2RR. The synthesized Ni−NC−600 catalyst has the structure of single Ni atom coordinated with one N atom and three C atoms (Ni−N1C3), which is suggested by X-ray absorption spectroscopy. The Ni−NC−600 catalyst exhibits high CO2RR catalytic performance and a high CO Faraday efficiency above 98% in a wide potential range from −0.7 to −1.3 V (vs. reversible hydrogen electrode (RHE)), superior to most of the reported Ni−N−C catalysts. This work has developed a facile strategy to synthesize high performance CO2RR catalyst. [ABSTRACT FROM AUTHOR]

Conventional adhesives often emit volatile organic compounds (VOCs), which have a negative impact on human health. In this paper, an environmentally‐friendly supramolecular adhesive PD which has high adhesive and low VOCs emission is prepared by the reaction between polyethyleneimine (PEI) and 3,4‐dihydroxybenzaldehyde (DBA). PD containing abundant catechol groups exhibit excellent adhesion to wood substrates and is able to reach a maximum shear strength of 5.20 ± 0.39 MPa. One factor is attributed to multiple reactions between PEI, and DBA and oxidation of DBA. These reactions construct a complex three‐dimensional cross‐linked structure which is very helpful to improve the bonding performance of the adhesive. Another reason refers to the fact that a large number of catechol groups in PD can form a lot of hydrogen bonds with the amino group in PEI and the hydroxyl group in the wood substrate. These hydrogen bonds play an important role in enhancing shear strength. PD adhesives have a stronger bond strength than commercial chloroprene rubber (CR, Pattex‐PXL) and polyvinyl acetate adhesives (PVAc, JUJU‐8708) and have lower emissions of VOCs. As an environmentally‐friendly adhesive for wood‐based substrates, this adhesive may have potential applications in the wood processing industry. [ABSTRACT FROM AUTHOR]

Polycrystalline cubic boron nitride (PcBN) with excellent mechanical properties was sintered by using high activity TiC0.5 and metal aluminum as binder at high temperature and pressure. The effects of sintering temperature on phase composition, microstructure, relative density and mechanical properties of PcBN composites were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy spectrum analysis. The results show that, under the conditions of low reaction temperature of 1400°C and holding time of 10 min, excellent composite properties of PcBN sintered material were obtained. The reinforced phases such as Ti(C, N), TiB2 and AlN were stably presented in the sintered body. To be specific, the microhardness, flexural strength and fracture toughness of the sintered body first increased and then decreased with the increasing sintering temperature, as well as posessing a high fracture toughness, which were 39.74 GPa, 1217 MPa and 8.78 MPa m1/2, respectively. [ABSTRACT FROM AUTHOR]