Flame retardancy and thermal properties of organoclay and phosphorous compound synergistically modified epoxy resin

Phosphorous flame retardants (PFRs) are common halogen‐free flame retardants. However, the flame retardancy of PFRs has not been fully exploited. Herein, the synergistic flame retardant effect of a typical phosphorous compound, 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO), and organoclay on epoxy is studied. Results show that the peak of heat release rate (pHRR) and smoke production rate of modified epoxy resin (EP) with both 2.0 wt % phosphorus and 4.0 wt % organoclay are only 40% and 46% of that of neat EP resin, respectively, while the sole use of 2.0 wt % phosphorus only decrease the pHRR to 59% of that of neat EP resin. The structure and thermal decomposition behavior of as‐prepared nanocomposites are analyzed, and a synergistic flame retardant mechanism is proposed. This investigation opens a new approach to obtain halogen‐free EPs with higher flame retardancy and better overall properties than the EPs loaded with DOPO only. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43367.     

Synthesis of Novel Double-Layer Nanostructures of SiC–WO x by a Two Step Thermal Evaporation Process

A novel double-layer nanostructure of silicon carbide and tungsten oxide is synthesized by a two-step thermal evaporation process using NiO as the catalyst. First, SiC nanowires are grown on Si substrate and then high density W₁₈O₄₉ nanorods are grown on these SiC nanowires to form a double-layer nanostructure. XRD and TEM analysis revealed that the synthesized nanostructures are well crystalline. The growth of W₁₈O₄₉ nanorods on SiC nanowires is explained on the basis of vapor–solid (VS) mechanism. The reasonably better turn-on field (5.4 V/μm) measured from the field emission measurements suggest that the synthesized nanostructures could be used as potential field emitters. Hyeyoung Kim and Karuppanan Senthil contributed equally to this article.     

Microstructure and Polarization Studies on Interlayer Free La0.65Sr0.3Co0.2Fe0.8O3–δ Cathodes Fabricated on Yttria Stabilized Zirconia by Solution Precursor Plasma Spraying

Nano‐structured cathodes of La_0.65Sr_0.3Co_0.2Fe_0.8O_3–δ (LSCF) are fabricated by solution precursor plasma spraying (SPPS) on yttria stabilized zirconia (YSZ) electrolytes (LSCF‐SPPS‐YSZ). Phase pure LSCF is obtained at all plasma power. Performances of LSCF‐SPPS‐YSZ cathodes are compared with conventionally prepared LSCF cathodes on YSZ (LSCF‐C‐YSZ) and gadolinium doped ceria (GDC) (LSCF‐C‐GDC) electrolytes. High R_p is observed in the LSCF‐C‐YSZ (∼42 Ohm cm² at 700 °C) followed by LSCF‐C‐GDC (R_p ∼ 1.5 Ohm cm² at 700 °C) cathodes. Performance of the LSCF‐SPPS‐YSZ cathodes (R_p ∼ 0.1 Ohm cm² at 700 °C) is found to be even superior to the performance of LSCF‐C‐GDC cathodes. High performance in LSCF‐SPPS‐YSZ cathodes is attributed to its nano‐structure and absence of any interfacial insulating phase which may be attributed to the low temperature at the interaction point of LSCF and YSZ and low interaction time between LSCF and YSZ during SPPS process. In the time scale of 100 h, no change in the polarization resistances is observed at 750 °C. Based on the literature and from the present studies it can be stated that SOFC with YSZ electrolyte and LSCF‐SPPS‐YSZ cathode can be operated at 750 °C for a longer duration of time and good performance can probably be achieved.