Southwest University of Science and Technology

About: Southwest University of Science and Technology is a education organization based out in Mianyang, China. It is known for research contribution in the topics: Adsorption & Graphene. The organization has 10017 authors who have published 8923 publications receiving 94850 citations. The organization is also known as: Xīnán Kējìdàxué.

Boosted Reactivity of Ammonia Borane Dehydrogenation over Ni/Ni2P Heterostructure.

Abstract: Ammonia borane (AB) is regarded as a highly promising candidate for chemical hydrogen-storage materials. Developing low-cost yet efficient catalysts for the dehydrogenation of AB is central to achieving hydrogen conversion. Here a heterostructure of Ni/Ni2P nanoparticles deposited on a defective carbon framework for the hydrolysis of AB is developed by elaborately controlling phosphorization conditions. The electronic structure and interfacial interaction of the ternary components are probed by synchrotron-based X-ray absorption fine structure and further simulated via density functional theory. By adjusting the content of Ni and Ni2P in the hetrostructure, the optimized hybrid exhibits catalytic performance of H2 generation from the hydrolysis of AB under ambient conditions with a turnover frequency of 68.3 mol (H2) mol-1 (Cat) min-1 and an activation energy ( Ea) of 44.99 kJ mol-1, implying its high potential as an efficient supplement for noble-metal-based catalysts in hydrogen energy applications.

Multifunctional load-bearing hybrid hydrogel with combined drug release and photothermal conversion functions

Abstract: The inability of damaged load-bearing cartilage to regenerate and self-repair remains a long-standing challenge in clinical settings. In the past, the use of PVA hydrogels as cartilage replacements has been explored; however, both pristine and annealed PVA are not ideal for load-bearing cartilage applications, and new materials with improved properties are highly desirable. In this work, we developed a novel hybrid hydrogel system consisting of glycerol-modified PVA hydrogel reinforced by a 3D printed PCL-graphene composite scaffold. The composition of the hydrogel within the hybrid material was optimized to achieve high water retention and enhanced stiffness. The hybrid hydrogel formed by reinforcement with a 3D printed PCL-graphene scaffold with optimized architecture demonstrated desirable mechanical properties (stiffness, toughness, and tribological properties) matching those of natural load-bearing cartilage. Our novel hydrogel system has also been designed to provide drug release and on-demand photothermal conversion functions and at the same time offers excellent biocompatibility with low cell adhesion. These promising properties may allow our unique hybrid hydrogel system to be used for potential applications, such as load-bearing cartilage repair/replacement, as well as targeting certain challenging clinical conditions, such as the treatment of severe arthritis. A hybrid hydrogel for replacing damaged cartilage has been developed by researchers in China and the UK. Fibrocartilage - the toughest type of cartilage found between the intervertebrae discs and the knee joints, is able to withstand heavy weights. The damage of such cartilage is difficult to repair and scientists have begun to investigate hydrogels as an artificial cartilage replacement. A hydrogel is a soft spongy material made from interconnected polymers; however, conventional hydrogels are not well-suited to load-bearing applications. Dan Sun from Queen’s University Belfast, Li Zhang from Sichuan University, Chengdu, and co-workers have reinforced a poly (vinyl alcohol) hydrogel with a scaffold made from a composite of graphene and another polymer called polycaprolactone. This scaffold increases the stiffness and toughness of the hydrogel, and has the added benefit of on-demand drug release. In this work, we developed a novel hybrid hydrogel system consisting of glycerol-modified PVA hydrogel reinforced by a 3D printed PCL-graphene composite scaffold. The biocompatible hybrid hydrogel shows desirable mechanical properties matching those of natural load-bearing cartilage, while providing drug release and on-demand photothermal conversion functions. These promising properties may allow their potential applications in load-bearing cartilage repair/replacement and treatment of severe arthritis.

Effect of aluminum diethylphosphinate on flame retardant and thermal properties of rigid polyurethane foam composites

Abstract: Rigid polyurethane foam/aluminum diethylphosphinate (RUPF/ADP) composites were prepared by one-step water-blown method. Furthermore, scanning electron microscope (SEM), thermal conductivity meter, thermogravimetric analysis (TGA), limiting oxygen index, Underwriters Laboratories vertical burning test (UL-94) and microsacle combustion calorimetry were applied to investigate thermal conductivity, thermal stability, flame retardancy and combustion behavior of RPUF/ADP composites. Thermogravimetric analysis–Fourier transform infrared spectroscopy (TG–FTIR) was introduced to investigate gaseous products in degradation process of RPUF/ADP composites, while SEM and X-ray photoelectron spectroscopy were used to research char residue of the composites. It was confirmed that RPUF/ADP composites presented well cell structure with density of 53.1–59.0 kg m−3 and thermal conductivity of 0.0425–0.0468 W m−1 K−1, indicating excellent insulation performance of the composites. Flame retardant test showed that ADP significantly enhanced flame retardancy of RPUF/ADP composites, RPUF/ADP30 passed UL-94 V-1 rating with LOI of 23.0 vol%. MCC test showed that ADP could significantly decrease peak of heat release rate (PHPR) of RPUF/ADP composites. PHPR value of RPUF/ADP20 was decreased to 158 W g−1, which was 21.8% reduced compared with that of pure RPUF. TG–FTIR test revealed that the addition of ADP promoted the release of CO2, hydrocarbons and isocyanate compound in first-step degradation of RPUF matrix while inhibited the release of CO in second step degradation. Char residue analysis showed that the addition of ADP promoted polyurethane molecular chain to form aromatic and aromatic heterocyclic structure, enhancing strength and compactness of the char. This work associated a gas–solid flame retardancy mechanism with the incorporation of ADP, which presented an effective strategy for preparation of flame retardant RPUF composites.