•PVP-g-SiO2 was prepared by free radical polymerization.•HXNBR-(PVP-g-SiO2) latex film was prepared by diimide reduction of XNBR latex.•Improved dispersity of PVP-g-SiO2 improved the mechanical properties of HXNBR.A polyvinyl pyrrolidone grafted silica (PVP-g-SiO2) was prepared by free radical polymerization of N-vinyl-2-pyrrolidone and characterized by FTIR, TGA, SEM, and XPS, and the effect of catalyst concentration and reaction time on PVP-g-SiO2 was studied. A PVP-g-SiO2 reinforced hydrogenated carboxylated nitrile (HXNBR-(PVP-g-SiO2)) latex film was prepared by diimide reduction of XNBR latex and doping of PVP-g-SiO2. The HXNBR-(PVP-g-SiO2) latex film exhibited improved mechanical properties, due to the improved dispersity of PVP-g-SiO2 in HXNBR.Download high-res image (144KB)Download full-size image

An easy, large-scale synthesis of N-doped carbon quantum dots (CQDs) was developed by using isophorone diisocyanate (IPDI) as a single carbon source under microwave irradiation. The yield of raw N-doped CQDs was about 83%, which is suitable for industrial-scale production. A detailed formation mechanism for N-doped CQDs involving self-polymerization and condensation of IPDI was demonstrated. Moreover, the obtained N-doped CQDs can be homogeneously dispersed in various organic monomers and do not need toxic organic solvents as dispersing agents. This advantage expands the range of applications of CQDs in composites. The N-doped CQDs dispersed in polyurethane (PU) matrixes emit not only fluorescence but also phosphorescence and delayed fluorescence at room temperature upon excitation with ultraviolet (UV) light. Furthermore, the phosphorescence of CQD/PU composites is sensitive to oxygen and therefore, the obtained-CQDs could be exploited in the development of novel oxygen sensors.

A hydrogenated hydroxy-terminated butadiene–acrylonitrile copolymer (HHTBN)-based polyurethane elastomer (PUE) was prepared by using HHTBN as the soft segments in a casting method. The HHTBN-based PUE exhibited improved mechanical properties and aging resistance.

In this study, novel 1-methylpropargyl alcohol derivatives containing leucine side groups on their side chains were successfully synthesized and polymerized using (nbd)Rh+[η6-C6H5B−(C6H5)3] as catalyst. Circular dichroism (CD) and ultraviolet–visible (UV–Vis) spectra revealed that the polymers took predominantly one-handed helical structures that were stable under heat. Deprotection of the t-butyloxycarboryl (Boc) groups in the homopolymers under acidic conditions produced polymers with primary amine moieties on the side chains. The polymers were soluble in aqueous medium, and turbidity test revealed that they were pH-responsive. Amino acid-based polymers were further used in the enantionselective crystallization of alanine enantiomers and l-alanine was preferably induced to crystallize with the l-leucine-based polymer.

A rhodium (Rh)–SiO2 fiber catalyst was prepared by electrospinning, calcination, and reduction in that order. The as-prepared Rh–SiO2 fiber catalyst was applied in the catalytic hydrogenation of alkenes. This catalyst allowed the hydrogenation reaction to be carried out at room temperature with excellent catalytic activity and could be reused nine times without obvious loss of catalytic activity. The excellent mechanical strength, thermal stability, and chemical stability of SiO2 and the uniform dispersion of the Rh nanoparticles in the fibers are the reasons for the superior activity and reusability of the catalyst.

An efficient and recyclable catalyst was prepared by depositing rhodium nanoparticles (Rh NPs) on a SiO2 support with the surface modified by 3-aminopropyl-trimethoxysilane (APTS). The obtained catalyst, Rh(III)/MSiO2, was extensively characterized by FTIR, SEM, XRD, XPS, BET, and ICP to demonstrate the incorporation of amine groups on the surface of the modified SiO2. The hydrogenation of acrylonitrile butadiene rubber (NBR) was used to evaluate the catalytic properties of Rh(III)/MSiO2, and a 98.68% conversion and nearly 100% selectivity to CC were obtained under optimum conditions (120 °C, 3.0 MPa H2, 8 h). A comparative study was made between Rh(III)/MSiO2 and Rh(III)/SiO2 in the hydrogenation of NBR, and Rh(III)/MSiO2 showed higher activity and higher stability. The results indicated that the increase of the amount of deposited metal particles and the improvement of the adhesion of metal particles to the support are the reasons for the high performance of Rh(III)/MSiO2. In addition, the Rh(III)/MSiO2 could be easily recovered by centrifugation and reused 3 times with only a slight loss in activity and selectivity. Furthermore, this modified method can be extended to other heterogeneous catalyst systems to improve their activity, recyclability and stability.

An Rh-based complex, T-Rh-PPh3, was developed through a facile one-step process. The T-Rh-PPh3 exhibited high activity and air stability in the hydrogenation of acrylonitrile–butadiene rubber. The enhanced air stability can be ascribed to the phenolic hydroxyl structures in tannin.

Here, we report a three-layer-structured hybrid nanostructure consisting of transition metal oxide TiO2 nanoparticles sandwiched between carbonaceous polymer polyaniline (PANI) and graphene nanosheets (termed as PTG), which, by simultaneously hindering the agglomeration of TiO2 nanoparticles and enhancing the conductivity of PTG electrode, enables fast discharge and charge. It was demonstrated that the PTG exhibited improved electrochemical performance compared to pure TiO2. As a result, PTG nanocomposite is a promising anode material for highly efficient lithium ion batteries (LIBs) with fast charge/discharge rate and high enhanced cycling performance [discharge capacity of 149.8 mAh/g accompanying Coulombic efficiency of 99.19% at a current density of 5C (1000 mA/g) after 100 cycles] compared to pure TiO2. We can conclude that the concept of applying three-layer-structured graphene-based nanocomposite to electrode in LIBs may open a new area of research for the development of practical transition-metal oxide graphene-based electrodes which will be important to the progress of the LIBs science and technology.

Carbon quantum dots (CQDs) have been widely studied; however, nearly all CQDs can only be used either in aqueous phase or oil phase. There is much less attention on amphiphilic CQDs (ACDs) and their potential applications. In this work, ACDs were successfully prepared by a one-pot hydrothermal treatment of oil soluble N-doped CQDs. The obtained ACDs exhibit favorable aqueous solubility, high photoluminescence (PL) quantum yields, and excellent photostability, showing great potential in Fe3+ ion detection. Interestingly, up-conversion PL of the ACDs is also observed and successfully applied in two-photon cell imaging. In addition, the obtained ACDs can be homogeneously dispersed into polyvinyl alcohol (PVA) and polyurethane matrices. Importantly, a room temperature phosphorescence phenomenon can be detected in these ACD-based composites and the ACD/PVA composite films show an ultralong phosphorescence lifetime (450 ms), which expands the scope of research and applications of CQDs.