Robust, Lightweight, Hydrophobic, and Fire-Retarded Polyimide/MXene Aerogels for Effective Oil/Water Separation.

Polyimide (PI) aerogels have attracted great attention owing to their low density and excellent thermal stability. However, hydrophobic surface modification is required for PI aerogels to improve their ability in oil/water separation due to their amphiphilic characteristic. Two-dimensional MXenes (transition metal carbides/nitrides) can be utilized as nanofillers to enhance the properties of polymers because of their unique layered structure and versatile interface chemistry. Herein, the robust, lightweight, and hydrophobic PI/MXene three-dimensional architectures were fabricated via freeze-drying of polyamide acid/MXene suspensions and thermal imidization. Polyamide acid was synthesized using N-N-dimethylacetamide and 4,4'-oxydianiline. MXene (Ti3C2Tx) dispersion was obtained via the etching of Ti3AlC2 and ultrasonic exfoliation. Taking advantage of the strong interaction between PI chains and MXene nanosheets, the interconnected, highly porous, and hydrophobic PI/MXene aerogels with low density were fabricated, resulting in the improved compressive performance, remarkable oil absorption capacity, and efficient separation of oil and water. For the PI/MXene-3 aerogel (weight ratio, 5.2:1) without any surface modification, the water contact angle was 119° with a density of 23 mg/cm3. This aerogel can completely recover to its original height after 50 compression-release cycles, exhibiting superelasticity and exceptional fatigue-resistant ability. It also showed high absorption capacities to various organic liquids ranging from approximately 18 to 58 times of their own weight. This hybrid aerogel can rapidly separate the chloroform, soybean oil, and liquid paraffin from the water-oil system. The thermally stable hybrid aerogel also exhibited excellent fire safety properties and outstanding reusability under an extreme environment.

Functionalization of MXene Nanosheets for Polystyrene towards High Thermal Stability and Flame Retardant Properties.

Fabricating high-performance MXene-based polymer nanocomposites is a huge challenge because of the poor dispersion and interfacial interaction of MXene nanosheets in the polymer matrix. To address the issue, MXene nanosheets were successfully exfoliated and subsequently modified by long-chain cationic agents with different chain lengths, i.e., decyltrimethylammonium bromide (DTAB), octadecyltrimethylammonium bromide (OTAB), and dihexadecyldimethylammonium bromide (DDAB). With the long-chain groups on their surface, modified Ti3C2 (MXene) nanosheets were well dispersed in N,N-dimethylformamide (DMF), resulting in the formation of uniform dispersion and strong interfacial adhesion within a polystyrene (PS) matrix. The thermal stability properties of cationic modified Ti3C2/PS nanocomposites were improved considerably with the temperatures at 5% weight loss increasing by 20 °C for DTAB-Ti3C2/PS, 25 °C for OTAB-Ti3C2/PS and 23 °C for DDAB-Ti3C2/PS, respectively. The modified MXene nanosheets also enhanced the flame-retardant properties of PS. Compared to neat PS, the peak heat release rate (PHRR) was reduced by approximately 26.4%, 21.5% and 20.8% for PS/OTAB-Ti3C2, PS/DDAB-Ti3C2 and PS/DTAB-Ti3C2, respectively. Significant reductions in CO and CO2 productions were also obtained in the cone calorimeter test and generally lower pyrolysis volatile products were recorded by PS/OTAB-Ti3C2 compared to pristine PS. These property enhancements of PS nanocomposites are attributed to the superior dispersion, catalytic and barrier effects of Ti3C2 nanosheets.

Novel 3D Network Architectured Hybrid Aerogel Comprising Epoxy, Graphene, and Hydroxylated Boron Nitride Nanosheets.

A novel three-dimensional (3D) epoxy/graphene nanosheet/hydroxylated boron nitride (EP/GNS/BNOH) hybrid aerogel was successfully fabricated in this study. This was uniquely achieved by constructing a well-defined and interconnected 3D network architecture. The manufacturing process of EP/GNS/BNOH involved a simple one-pot hydrothermal strategy, followed by the treatment of freeze-drying and high-temperature curing. In comparison with EP/GNS-3, EP/GNS/BNOH-3 demonstrated improvement of 97% for compressive strength at 70% strain. Through compression tests, fracture occurred for EP/GNS-3 at ninth compression cycles, whereas EP/GNS/BNOH-3 retained its original form after twenty compression cycles, with a residual height of 97% (i.e., only 3% reduction). By the addition of BNOH in the polymer matrix, the dynamic heat transfer and dissipation rates of EP/GNS/BNOH aerogels were also considerably reduced, indicating that the aerogel with BNOH additive possessed excellent thermal insulation properties. Thermogravimetric analysis results revealed that the thermal stabilities of EP/GNS and EP/GNS/BNOH aerogels were improved with increasing loading of EP, and EP/GNS/BNOH aerogels exhibited a better thermal stability at high temperatures. Through the elevated levels attained in the compressive strength, superelasticity, and thermal resistance, EP/GNS/BNOH aerogels has the great potential of being a very effective thermal insulation material to be utilized across a board range of applications in building, automotive, spacecraft, and mechanical systems.

Comparative Studies on Thermal, Mechanical, and Flame Retardant Properties of PBT Nanocomposites via Different Oxidation State Phosphorus-Containing Agents Modified Amino-CNTs.

High-performance poly(1,4-butylene terephthalate) (PBT) nanocomposites have been developed via the consideration of phosphorus-containing agents and amino-carbon nanotube (A-CNT). One-pot functionalization method has been adopted to prepare functionalized CNTs via the reaction between A-CNT and different oxidation state phosphorus-containing agents, including chlorodiphenylphosphine (DPP-Cl), diphenylphosphinic chloride (DPP(O)-Cl), and diphenyl phosphoryl chloride (DPP(O3)-Cl). These functionalized CNTs, DPP(Ox)-A-CNTs (x = 0, 1, 3), were, respectively, mixed with PBT to obtain the CNT-based polymer nanocomposites through a melt blending method. Scanning electron microscope observations demonstrated that DPP(Ox)-A-CNT nanoadditives were homogeneously distributed within PBT matrix compared to A-CNT. The incorporation of DPP(Ox)-A-CNT improved the thermal stability of PBT. Moreover, PBT/DPP(O3)-A-CNT showed the highest crystallization temperature and tensile strength, due to the superior dispersion and interfacial interactions between DPP(O3)-A-CNT and PBT. PBT/DPP(O)-A-CNT exhibited the best flame retardancy resulting from the excellent carbonization effect. The radicals generated from decomposed polymer were effectively trapped by DPP(O)-A-CNT, leading to the reduction of heat release rate, smoke production rate, carbon dioxide and carbon monoxide release during cone calorimeter tests.

Clinical features and treatment of acute clenbuterol poisoning in children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study clinical features, treatment and curative effects in children with acute clenbuterol poisoning, in order to provide a basis for early diagnosis and treatment.</p><p><b>METHODS</b>Clinical data of 28 hospitalized children with acute clenbuterol poisoning in April 2011 were retrospectively studied.</p><p><b>RESULTS</b>Of the 28 patients, there were 15 males and 13 females, aged 1 to 13 years (mean age 6.5±4.8 years). Vomiting, palpitations and limb shaking were found as main clinical manifestations in the patients. Main changes of blood biochemical included hypokalemia, lactic acidosis, hyperglycemia, hypsocreatinkinase. Snus tachycardia and S-T segment depression were observed on ECG. Patients' symptoms were gradually alleviated after 12-78 hours by use of beta blockers, potassium supplement, protecting the heart and other symptomatic and supportive treatment. Blood biochemical indexes were improved after 48 hours of admission. All of the patients were cured after 5 days. The symptoms of the patients do not longer occur during a follow up of half a month.</p><p><b>CONCLUSIONS</b>Acute clenbuterol poisoning is characterized by vomiting, palpitations, limb shaking, hypokalemia, lactic acidosis and tachycardia in children. An early effective treatment of this disease can improve prognosis in children.</p>

Report of the first human case of H5N1 avian influenza pneumonia in Hunan, China / 中华儿科杂志

<p><b>OBJECTIVE</b>To summarize and analyze the clinical characteristics and diagnostic and therapeutic measures for the first human case of H5N1 avian influenza pneumonia in mainland of China.</p><p><b>METHODS</b>The clinical data of the first case of H5N1 avian influenza virus infection in China were analyzed and summarized.</p><p><b>RESULTS</b>The case is a 9-year old boy, who developed acute symptoms of a light common respiratory infection, including fever and dry cough without obvious catarrh. On the 7th day after onset, his temperature reached 40 degrees C, tachypnea occurred, distinct rales could be heard and large areas of consolidation were seen in the lungs on chest X-ray. The patient's peripheral blood leukocyte count was 2.81 x 10(9)/L and neutrophils dominated. After comprehensive therapeutic approaches, including antiviral therapy (amantadine) and use of low-dosage glucocorticoid, the patient's temperature returned to normal on the 3rd hospitalization day, chest X-ray showed absorbed inflammatory change on the 5th day after admission, and leukocyte count became normal on the 6th day. No complication occurred during the whole course. The case was diagnosed by the 4 fold raised antibody to the H5N1 influenza virus in recovery stage serum because the H5N1 nucleic acid test in early stage was negative. The case was cured and discharged after 3 weeks comprehensive treatment.</p><p><b>CONCLUSIONS</b>It is very important for clinicians to pay enough attention to epidemiological history, especially history of exposure to avian influenza virus contaminated material, which will be very helpful for early detection, early diagnosis of the disease, and also very important for effective treatment and better prognosis.</p>