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The massive production and accumulation of industrial solid waste-iron tailings not only occupy valuable land resources but also easily cause environmental pollution and personnel injury. Based on this, the thermoplastic polyurethane (TPU)/modified iron tailings (MIT) composites were prepared by surface modification of iron tailings (MIT) and adding it as flame retardant to TPU. The combustion performance and smoke toxicity of TPU/MIT composites were analyzed by thermogravimetric analysis (TG), thermogravimetric-spectroscopy (TG-IR) and cone calorimetry (CCT). The morphology and structure of the carbon slag of the composites were analyzed by scanning electron microscopy(SEM) and Raman spectroscopy. The results showed that the initial thermal decomposition temperature (T-5%) of TPU/MIT30 composite increased at about 7oC, and the residual carbon content at 700oC increased from 3.13 wt% to 32.17 wt%. The peak heat release rate(PHRR), total heat release(THR) and total smoke release(TSR) of TPU/MIT30 composite decreased from 800.6 kW/m2, 83.1 MJ/m2 and 827.6 m2/m2 of pure TPU to 488.0 kW/m2, 63.6 MJ/m2 and 517.4 m2/m2, respectively. The SEM and Raman1 spectroscopy of char residue showed that the compactness and graphitization degree of char residue for TPU/MIT30 composite was the highest, indicating that the MIT could effectively improve the fire safety of TPU composites. This study provided some ideas for the high-value utilization of iron tailings. [ABSTRACT FROM AUTHOR]

Low flame retardant efficiency is a key bottleneck for currently available retardants against the flammable polypropylene (PP). Herein, the organically modified montmorillonite (OMMT) was utilized as a synergist for our previously reported intumescent flame retardant (IFR) that was constructed from ammonium polyphosphate (APP) and hyperbranched charring foaming agent (HCFA) to further enhance the retardant efficiency against PP. The resultant's combustion behavior was thoroughly investigated by cone calorimetry, limiting oxygen index (LOI), vertical burning test (UL-94), and scanning electron microscopy (SEM). The results showed that 20% addition of IFR with OMMT showed a positive effect and improved the flame retardancy of the PP systems. Especially, addition of 2 wt% OMMT obviously increased the LOI values of PP systems with 20% total loading flame retardants from 29% to 31.5% and the samples meet V-0 rating as well as the reduction of the heat release rate (HRR), total heat release (THR), CO2, and CO production occurred. On the other hand, the SEM images were also revealed that OMMT initiated a dense and strong char on the surface of the material, which resulted in efficient flame retardancy of PP matrix during combustion. In addition, thermal degradation behavior discussed by thermogravimetric analysis (TGA) indicated that OMMT could improve the thermal stability of PP systems under high temperature, and promoted char residues of PP/IFR systems. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A novelhyperbranched char foaming agent (HCFA), successfully synthesizedvia the polycondensation of 2-chloro-4,6-di-(2-hydroxyethylamino)-s-triazine(CHT), was combined with ammonium polyphosphate (APP) to endow polypropylene(PP) with flame retardance. The study of thermal stability of variousPP composites showed that HCFA/APP system could effectively improvethe thermal degradation and thermal-oxidative stability of the charresidues, and PP3 containing 30 wt % APP/HCFA with a 3/1 weight ratioleft the highest amount of char residue at 700 °C. The resultsof flammability revealed that PP3 had the most effective flame retardancyand lowest fire hazards. The investigation of structure and morphologyof char residues indicated that the compact and foaming char layer,as a good barrier against the transmission of heat and volatiles,was formed for PP3 during combustion. [ABSTRACT FROM AUTHOR]

We had developed a facile synthetic route of Co 3 O 4 crystals with different morphologies via one step template-free hydrothermal method. The phase and composition of the Co 3 O 4 were investigated by X-ray powder diffraction and Raman spectrum. The morphology and structure of the synthesized samples were characterized by scanning electron microscopy and transmission electron microscopy. The H 2 O 2 played a crucial role in morphological control of Co 3 O 4 nanostructures. It only obtained Co-based precursor in the absence of H 2 O 2 . On the contrary, the Co 3 O 4 with different morphologies including nanoparticles, nano-discs and well-defined octahedral nanostructures were synthesized in the presence of H 2 O 2 . In addition, the optical property of the obtained Co 3 O 4 samples was investigated by UV–vis spectra. [ABSTRACT FROM AUTHOR]

A series of sodium alginate (SA) nanocomposite films with different loading levels of graphitic-like carbon nitride (g-C3N4) were fabricated via the casting technique. The structure and morphology of nanocomposite films were investigated by X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. Thermogravimetric analysis results suggested that thermal stability of all the nanocomposite films was enhanced significantly, including initial thermal degradation temperature increased by 29.1 °C and half thermal degradation temperature improved by 118.2 °C. Mechanical properties characterized by tensile testing and dynamic mechanical analysis measurements were also reinforced remarkably. With addition of 6.0 wt % g-C3N4, the tensile strength of SA nanocomposite films was dramatically enhanced by 103%, while the Young's modulus remarkably increased from 60 to 3540 MPa. Moreover, the storage modulus significantly improved by 34.5% was observed at loadings as low as 2.0 wt %. These enhancements were further investigated by means of differential scanning calorimetry and real time Fourier transform infrared spectra. A new perspective of balance was proposed to explain the improvement of those properties for the first time. At lower than 1.0 wt % loading, most of the g-C3N4 nanosheets were discrete in the SA matrix, resulting in improved thermal stability and mechanical properties; above 1.0 wt % and below 6.0 wt % content, the aggregation was present in SA host coupled with insufficient hydrogen bondings limiting the barrier for heat and leading to the earlier degradation and poor dispersion; at 6.0 wt % addition, the favorable balance was established with enhanced thermal and mechanical performances. However, the balance point of 2.0 wt % from dynamic mechanical analysis was due to combination of temperature and agglomeration. The work may contribute to a potential research approach for other nanocomposites.