A hexagonal Cu2SnS3 with uniform and well-dispersed nanoparticle morphology has been synthesized, representing an example of hexagonal system in the Cu–Sn–E (S, Se) ternary chalcogenides. Both theoretical calculation and experimental results give the unique metallic character of Cu2SnS3, which is significantly different from the traditional opinion that I-IV-VI ternary chalcogenides were regarded previously as small or middle band-gap semiconductors. Also, M(I)2SnS3 (M=Ag, Au, Rb, and Cs) serial compounds are another potential family of conducting sulfides. The conducting Cu2SnS3 product with the interlayer space and tunnels in the crystal structures could be fascinatingly introduced to the lithium battery application.

In this paper, thermoplastic phenol formaldehyde (PF) grafted cyclic neopentyl phosphate (PFCP) was synthesized by using PF and 2,2-dimethyl-1,3-propanediol phosphoryl chloride. It was characterized by Fourier transform infrared spectroscopy (FTIR), 1H and 31P nuclear magnetic resonance (NMR). Compared to PF, PFCP shows improved thermal and thermoxidative stability and allows itself to be used in polyamide 6 (PA6). A micro-intumescent flame retardant system was constructed by using cyclic neopentyl phosphate as acid source, PF as charring agent and PA6 whose decomposition products work as blowing agent. The results showed that PA6/PFCP composite is classified the UL-94 V-0 rating and get a LOI value of 35.5% at 25% loading of PFCP. SEM results showed that the outside of char residues is continuous and dense, but the inside is micro-intumescent and porous. XPS analysis of char revealed that most of phosphorus remained in the char layer. All the results suggest that the mode of flame retardant's action for PA6/PFCP composites is shifted from melting away to charring protection with the content of PFCP increasing. The coherent char generated by the decomposition of PFCP contributes most to flame retardancy of PA6.

The role of dual imidazolium polyoxometalates (POMs) in the flame retardancy of polypropylene/intumescent flame retardant (PP/IFR) composites was studied. The results showed that the structures of dual imidazolium POMs have a great effect on the flame retardancy of PP composites. The dual imidazolium POMs based on an ethyl group (EMIPMA) obtain the best flame retardant efficiency. With 15.5 wt % IFR and 0.5 wt % EMIPMA, the PP composites reach a limiting oxygen index of 25.7 and the UL‐94 V‐0 standard. However, the dual imidazolium POMs containing a butyl (BMIPMA) or hexyl (HMIPMA) group cannot achieve the UL‐94 V‐0 standard at the same formulation. Dual imidazolium POMs not only promote the formation of good char, but also induce the formation of intumescent char with a hierarchical and microporous structure that helps to prevent gas and heat from transferring from the flame to the resin. Therefore, the flame retardancy of PP/IFR composites is improved. However, excessive combustible components produced by BMIPMA or HMIPMA deteriorate the flame retardancy of PP/IFR composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45491.