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For the efficient utilization of CO2 into valuable product, the attractive carbon nitride catalysts have been widely studied. In this work, heptazine‐related materials with varying degree of polymerization were designed by an intrinsically modification strategy and employed in the cycloaddition of CO2 with the bisepoxide 1, 4‐butanediol diglycidyl ether (BDODGE). We initially figured out that the sample prepared at 450 °C contained more melem hydrate, exhibiting the best performance. The epoxides conversion and corresponding cyclic carbonates selectivity could achieve 93.1 % and 99.3 % at 140 °C for 20 h without any cocatalyst and solvent, respectively. Results of the catalytic tests suggested that the high catalytic activity was dependent on big size porous structure and the synergetic effect of active amino groups and −OH groups. The role of water in maintaining the specific structure and providing active site has been proved. Moreover, the CN‐450‐W catalyst exhibited outstanding recycling stability. And finally, a plausible reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]

Microcapsules with polydopamine composite shell layer were successfully synthesized by functionalizing silica‐modified microcapsules containing isophorone diisocyanate. The components and micromorphology of silica‐modified microcapsules at different reaction periods were studied by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy. The structure of different microcapsules was characterized by FTIR, 1H nuclear magnetic resonance and x‐ray photoelectron spectroscopy. The mechanical performances of different microcapsules were analyzed by nanoindentation technique. The compatibility and self‐healing efficiency of different microcapsules with the substrate were also investigated by the tensile tests. The results showed that the density of the silica‐modified microcapsule shell gradually increased and the mechanical performances were enhanced with the silica source. The hardness and elastic modulus of silica‐modified microcapsules in suitable core fraction (76.5 wt%) were 139.9 MPa and 2.2 GPa, which are 2.3 times and 4.8 times higher than those of untreated microcapsules, respectively. The functionalized modified microcapsules had excellent compatibility with the elastomeric substrate (PU‐PPG2000). At the same time, the self‐healing efficiency of the functionalized modified microcapsules in PU‐PPG2000 was 69.8%, which was 48.9% higher than that of the untreated microcapsules prepared under the same conditions. Silicon modification improved the density of microcapsules, enhancing their mechanical strength. At the same time, functionalization modification improved the interfacial bonding strength of microcapsules, further improving the compatibility with the polymer matrix. Highlights: Microcapsules with different silicon sources are characterized.Microcapsules are functionalized with polydopamine.Individual microcapsules are tested for mechanical strength by nanoindentation.The compatibility of the functionalized microcapsules is excellent.The self‐healing efficiency of modified microcapsules is greater than 70%. [ABSTRACT FROM AUTHOR]

Thermo‐mechanical properties are often the bottleneck for advanced applications of polyurethane (PU) elastomer materials. Carbon materials are emerging as promising reinforcing fillers for polymers due to their superior mechanical and conductive properties. In this study, carbon fiber‐graphene oxide (CF‐GO) multiscale reinforcements are fabricated for improving thermal‐mechanical properties of PU elastomers. To this end, CFs are firstly modified with GO via electrophoretic deposition and subsequently cooperate with free‐dispersed GO sheets in PU matrix. This multiscale reinforcing strategy effectively improved thermo‐mechanical properties and thermal stability of PU elastomer due to the improved CF‐PU interfacial interaction as well as the local stiffening of fiber‐matrix interphase by the dispersed GO sheets. This reinforcing approach also led to a synergistic increase in the thermal diffusivity of PU elastomer due to the formation of interconnected conductive network, in which CFs serve as a conductive framework that connects the free‐dispersed GO sheets. POLYM. COMPOS., 40:E953–E961, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The cycloaddition reaction of carbon dioxide (CO2) and bisepoxides is an interesting route for CO2 utilization and green non-isocyanate polyurethane (NIPU) synthesis. In this work, a series of γ-Al2O3 supported ZnBr2 and carbon nitride complex catalysts (Zn–CN/γ-Al2O3) were prepared by a simple thermal polymerization method and applied to the cycloaddition reaction. The results showed that 0.05Zn–CN/γ-Al2O3 exhibited high catalytic activity, over which 91.4% 1,4-butanediol diglycidyl ether (BDODGE) conversion and 98.9% cyclic carbonate selectivity were acquired under solvent and co-catalyst free conditions. The relationship between the structural properties and catalytic performance of Zn–CN/γ-Al2O3 catalysts was studied in detail. It is found that the high surface area and the synergistic effect of Lewis acid–base duality are key factors for the high activity of catalysts. Introducing ZnBr2 could provide acid sites and induce structure change of carbon nitride, which could determine the basic intensity of catalysts. Moreover, based on the elaborate discussions, a plausible catalytic reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]