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Intumescent flame retardants (IFRs) are widely used in preparing functional polymer composites , but it is still a challenge to improve their flame retardant efficiency. Herein nanosized nickel oxide (NiO) as synergist was incorporated into poly( l -lactic acid)/ammonium polyphosphate/silicone-containing macromolecular charring agent (PLA/APP/CSi-MCA) composites with the aim of improving their flame retardancy. According to limited oxygen index (LOI), vertical burning (UL-94) and cone calorimetry test results, the obtained PLA composites showed a LOI value as high as 33.0%, V0 ratting in UL-94 and 63.1% reduction for PHRR with the incorporation of 1 wt% NiO. The flame retardancy mechanism was also discussed by analyzing residual char structure and the composition of the liquid degradation products. It was found that the carbon layer contained two types of chars: APP and CSi-MCA could form char 1 via esterification and cross-linking reaction, while the PLA matrix could produce char 2 via the catalyzing carbonization of CSi-MCA and NiO to generate MWCNTs. The combination of char 1 and char 2 with better barrier effect resulted in the improvement on flame retardancy of PLA composites.

Stimuli-sensitive drug delivery systems show beneficial features of both medical and pharmaceutical fields. In this article, polymeric nanogel P (N-isopropylacrylamide-N,N '-dimethylaminoethyl methacrylate [NIPAM-DMAEMA]) (PND) with pH/redox/thermo-responsivenesses was synthesized by the in situ polymerization of NIPAM and DMAEMA for the controlled release of doxorubicin hydrochloride (DOX) and N,N '-bis(acryloyl)cystamine (BAC) and N,N '-methylenebisacrylamide (MBA) act as the crosslinkers, respectively. The structure, size, and zeta potential of PND-BAC and PND-MBA were further characterized. Moreover, after loading DOX, the encapsulation efficiency and the in vitro release behavior of PND-BAC/DOX and PND-MBA/DOX nanogels were discussed in detail. Compared to PND-MBA NGs, PND-BAC nanogels have redox degradability due to the presence of the crosslinker BAC. After loading DOX, the PND-BAC/DOX nanogel showed a higher encapsulation efficiency (81.6 ± 1.2)% and thermo- and pH-responsiveness as well as redox-responsive in vitro release. These properties together with excellent environmentally sensitive properties make PND-BAC as an attractive candidate for application in drug nanocarriers for the targeted drug delivery of model payloads. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1195-1203, 2019.

Mn3O4 and Mn3O4 (140)/CNTs have been investigated as high-capacity anode materials for lithium-ion batteries (LIBs) applications. Nanoparticle Mn3O4 samples were synthesized by hydrothermal method using Mn(Ac)2 and NH3·H2O as the raw materials and characterized by XRD, TG, EA, TEM, and SEM. Its electrochemical performances, as anode materials, were evaluated by galvanostatic discharge-charge tests. The Mn3O4 (140)/CNTs displays outstanding electrochemical performances, such as high initial capacity (1942 mAh g−1), stable cycling performance (1088 mAh g−1 and coulombic efficiency remain at 97% after 60 cycles) and great rate performance (recover 823 mAh g−1 when return to initial current density after 44 cycles). Compared to pure Mn3O4 (140), the improving electrochemical performances can be attributed to the existence of very conductive CNTs. The Mn3O4 (140)/CNTs with excellent electrochemical properties might find applications as highly effective materials in electromagnetism, catalysis, microelectronic devices, etc. The process should also offer an effective and facile method to fabricate many other nanosized metallic oxide/CNTs nanocomposites for low-cost, high-capacity, and environmentally benign materials for LIBs.

The catalysts containing Cu, Ni bi-metallic nanoparticles were successfully synthesized by in-situ reduction of Cu 2+ and Ni 2+ salts into the highly porous and hydrothermally stable metal-organic framework MIL-101 via a simple liquid impregnation method. When the total amount of loading metal is 3 × 10 −4 mol, Cu 2 Ni 1 @MIL-101 catalyst shows higher catalytic activity comparing to Cu x Ni y @MIL-101 with different molar ratio of Cu and Ni (x, y = 0, 0.5, 1.5, 2, 2.5, 3). Cu 2 Ni 1 @MIL-101 catalyst has the highest catalytic activity comparing to mono-metallic Cu and Ni counterparts and pure bi-metallic CuNi nanoparticles in hydrolytic dehydrogeneration of ammonia borane (AB) at room temperature. Additionally, in the hydrolysis reaction, the Cu 2 Ni 1 @MIL- 101 catalyst possesses excellent catalytic performances, which exhibit highly catalytic activity with turn over frequency (TOF) value of 20.9 mol H 2 min −1 Cu mol −1 and a very low activation energy value of 32.2 kJ mol −1 . The excellent catalytic activity has been successfully achieved thanks to the strong bi-metallic synergistic effects, uniform distribution of nanoparticles and the bi-functional effects between CuNi nanoparticles and the host of MIL-101. Moreover, the catalyst also displays satisfied durable stability after five cycles for the hydrolytically releasing H 2 from AB. The non-noble metal catalysts have broad prospects for commercial applications in the field of hydrogen-stored materials due to the low prices and excellent catalytic activity.

The poor conductivity is one of the prime reasons restricted MOFs to be applied in the lithium-ion battery system. For the sake of ameliorate this issue, the Ni/NiO was well loaded on the surface of Cr-based metal organic frameworks (MIL-101) by solution impregnation and in situ reduction method to form Ni/NiO@MIL-101(Cr) composites. The as-synthesized Ni/NiO@MIL-101(Cr) was characterized by X-ray powder diffractions, X-ray photoelectron spectroscopy, field emission scanning electron microscope and transmission electron microscope techniques. When used as anode for LIBs, the Ni/NiO@MIL-101(Cr) composite exhibited high reversible capacity (891 mAh g-1 after 100 cycles at a current density of 200 mA g-1) and stable cycle performance, the coulombic efficiency can maintain in the whole cycle above 95.0%. The reasons for that Ni/NiO@MIL-101(Cr) behaved outstanding electrochemical properties were discussed also. The Ni/NiO@MIL-101(Cr) can be used as promising material for lithium-ion battery application.

Mono-metal Pd, Ni and highly dispersed bimetallic PdNi alloy nanoparticles with different molar ratio supported on MIL-101 have been successfully synthesized by a simple liquid impregnation-reduction method. And XRD, TEM, EDX, ICP-AES, XPS, BET and FTIR were employed to characterize the above catalysts. Their catalytic activities were tested in the hydrogen generation from aqueous solution of ammonia borane at room temperature. The results show that the as-synthesized Pd 10 Ni 6 @MIL-101 catalyst exhibits the highest catalytic activity, with a total turn over frequency (TOF) value of 83.1 mol H 2 min −1 (mol Pd) −1 , and the activation energy (Ea) was determined to be 31.7 kJ mol −1 . The excellent catalytic activity has been successfully achieved thanks to the strong bimetallic synergistic effects from PdNi nanoparticals of the composites, uniform distribution of nanoparticles as well as bifunctional effects between PdNi alloy nanoparticles and the host of MIL-101. In particular, this catalyst shows satisfying durable stability after five cycles for the hydrolytic dehydrogenation of ammonia borane.

For the first time, ultrafine Ru nanoparticles are successfully deposited on MIL-53(Cr) and MIL-53(Al) by using a simple liquid impregnation strategy and then characterized the structure, size, composition and specific area of the catalysts with different Ru loading by XRD, TEM, EDX, ICP-AES, XPS and BET. Their catalytic activities had been examined in ammonia borane hydrolysis to generate hydrogen gas. The results show that the as-synthesized 2.65 wt% Ru@MIL-53(Cr) and 2.59 wt% Ru@MIL-53(Al) exhibit the highly catalytic activity, owing to the uniform distribution of Ru nanoparticles and bi-functional effects between Ru nanoparticles and the host of MIL-53. The turn over frequency (TOF) values of the Ru@MIL-53(Cr) and Ru@MIL-53(Al) catalysts are 260.8 and 266.9 mol H 2 min −1 (mol Ru) −1 and the activation energies (E a ) are determined to be 28.9 and 33.7 kJ mol −1 , respectively. Moreover, the two catalysts exhibit satisfying durable stability after five cycles for the hydrolytic dehydrogenation of ammonia borane.

In this work, via a simple liquid impregnation method, Co(BO2)2 nanoparticles are successfully loaded on the surface of Cr-based metal organic frameworks MIL-101 without destroying the three-dimensional organic frameworks. As received Co(BO2)2@MIL-101 composite shows the improved cyclability when serves as anode for rechargeable Li-ion batteries. The obtained Co(BO2)2@MIL-101 electrode demonstrates high reversible capacity of 810 mA h g−1 after 100 cycles at a current density of 200 mA g−1 and shows stable cycle performance (coulombic efficiency remains above 95%). The improvement could be attributed to MIL-101, which provides effective barrier spaces for Co(BO2)2 to relax the volumetric variation and maintains superior conductivity during the charge and discharge process.

It is a great challenge to fabricate polymer nanocomposites with synchronously improved comprehensive performances. Herein fullerene (C60) and nickel hydroxide (Ni(OH)2) were reactively modified by grafting of polypropylene (PP) chains, then they were added into PP matrix to construct a catalytic carbonization system. The resultant PP nanocomposites exhibited simultaneous improvements on thermal stability, flame retardancy and mechanical properties. The enhanced mechanism on thermal properties was mainly ascribed to the synergistically catalytic carbonization effect of C60/Ni(OH)2 on delaying the thermal decomposition of PP and forming better carbon layer during combustion. Besides, the trapping radicals of C60 and 3D network structure of nanofillers also were helpful to improve their flame retardancy. Moreover, the improvement on mechanical performances with balanced stiffness and toughness resulted from good dispersion of nanofillers and strong interfacial adhesion between nanofillers and polymer matrix. This work provided a facile and efficient strategy for designing and fabricating high-performance polymer nanocomposites.

It is a great challenge to improve the flame retardancy of polymer materials by adding eco-friendly magnesium hydroxide (Mg(OH)2) but simultaneously maintain satisfied mechanical performances. In this study, expanded graphite (EG) as a synergist was introduced into poly(butylene succinate) (PBS)/Mg(OH)2 system to investigate the effect of EG on their flame retardancy, thermal stability and mechanical properties. The results showed that only addition of 5 wt% EG into PBS/20 wt%Mg(OH)2 resulted in excellent flame retardancy, including that the LOI was 29.4%, the UL-94 rating reached to V0, and the PHRR decreased by 73%. These flame retarded parameters were comparable or even better than that of PBS/40 wt%Mg(OH)2 composites. More importantly, PBS/20 Mg(OH)2/5 EG presented much better thermal stability and mechanical properties than PBS/40 wt%Mg(OH)2, indicating a balanced improvement on comprehensive performances of PBS. Based on the comparison with PBS/20 Mg(OH)2/5Graphene(Gr) system and the structure analysis for residual chars, the mechanism for improved flame retardancy was attributed to the formation of gradient-structured char layer due to the helpful thermal expansion process of EG together with the decomposition of Mg(OH)2 during combustion, resulting in better barrier action to heat, oxygen and flammable gases via “labyrinth effect”. As far as we know, it is the first report that gradient-structured char layer was discussed in flame retarded polymer systems. Hence, this work provides not only a high-efficient synergist to improve the flame retardant efficiency of Mg(OH)2, but also useful guidelines to design polymer composites with balanced comprehensive performances.