Summary Copper is among the most frequently found metallic residues in fire scene environment. Investigations on the thermal patterns produced on copper after fire scene exposure can provide important physical evidence for fire cause/origin determination. In this paper, the high temperature oxidation behaviors and the accompanying micro‐structural changes of pure copper have been studied in air and laboratory simulated kerosene‐combustion atmospheres at 600–800 °C. The oxidation kinetics, morphologies and microstructures of the oxide scales‐substrate were characterized by thermogravimetric analysis, scanning electron microscopy, energy‐dispersive spectroscopy and X‐ray diffractions. The results reveal that the increasing temperature can significantly affect the oxide properties and modify the substrate metallurgical microstructure. Especially, the presence of kerosene in the environmental atmosphere has caused accelerated oxidation and produced oxide scales different from those formed in air alone. These feature evolutions in surface oxides and substrate are expected to offer complementary insight on determining the fire characteristics, such as the exposure temperature, time period and whether liquid accelerant is involved. Copyright © 2016 John Wiley & Sons, Ltd.

A novel silicon-containing phthalonitrile monomer named bis(4-(4′-(4′-phenoxy)phenyl)phenyl)dimethylsilane phthalonitrile (SiBPPN) was successfully designed and synthesized. The chemical structure was characterized by proton nuclear magnetic resonance and Fourier transform infrared (FTIR) analyses, and its molecular weight was determined by mass spectrometry. Its melting point is lower than that of 4,4′-bis(3,4-dicyanophenoxy)biphenyl (BPPN), which has no silicon atom, and its solubility is also much better than that of BPPN. The curing behavior of SiBPPN was studied by differential scanning calorimetry and FTIR analyses in detail. The thermal and thermomechanical properties of the polymer and laminate were studied by thermogravimetric analysis and dynamic mechanical analysis. The results show that the cured SiBPPN (c-SiBPPN) possesses excellent thermal and mechanical properties. Under nitrogen atmosphere, its residual weight ratio at 800°C is 81.5% and the 5% thermal degradation temperature is 546°C. In addition, quartz-fiber (QF)-reinforced c-SiBPPN composites exhibit mechanical properties superior to those of QF-reinforced cured BPPN composites. The interlaminar shear strength and bending strength of the composite are 30.44 and 389 MPa at room temperature, and the interlaminar shear strength and bending strength of the composite are 22.25 and 339 MPa at 300°C.

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Due to the excellent thermo-stability, ablation resistance and superior dielectric properties, poly-silicon-containing arylacetylene resin (PSA) shows a promising application in aerospace and spaceflight industries as a composite matrix with quartz fiber (QF). However, the non-polar nature of PSA hamper the interfacial interaction with the QF resulting in a relatively weak mechanical strength for the whole QF/PSA composites. This can be alleviated by incorporating a coupling agent between QF and PSA to reinforce their interaction. Here, new coupling agents, three ethynyl silazane derivatives, were synthesized to improve QF/PSA composite mechanical properties and named as bis (3-ethynylaniline)-diphenylsilane (SZPP), bis (3-ethynylaniline)-methylphenylsilane (SZMP) and bis (3-ethynylaniline)-phenylvinylsilane (SZPV). For SZPP, about 3.0 wt% addition of this coupling agent increased the interlaminar shear strength and flexural strength of QF/PSA composite by 21.2% and 18.4%, respectively, compared with the untreated composite. Meanwhile, among the three coupling agents, SZPV showed the best improvement in enhancing the interlaminar shear strength and flexural strength of QF/PSA composites, which reached 34.1% and 41.7%, respectively.

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