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Lanthanum phenylphosphonate (LaHPP) was synthesized through solution reflux method with a hydrothermal reaction. The synergistic effect of decabromodiphenyl oxide (DBDPO) and LaHPP on thermal stability and flame retardancy of polycarbonate (PC) were investigated. Transmission electron microscope graphs showed that LaHPP dispersed well in the PC matrix. Thermogravimetric analyses indicated that the addition of LaHPP into PC/DBDPO composites led to better thermal stability. An appropriate content (1 wt%) of LaHPP could improve the UL94 rating (from V‐2 to V‐0) and limiting oxygen index value (from 32.8 to 40.5%) dramatically, and also brought an effective reduction in peak heat release rate and smoke release rate in cone calorimeter. Investigation of gaseous pyrolysis products and char residues demonstrated that LaHPP promoted the formation of more compact and solid chars, which acted as physical barriers to inhibit heat and oxygen transfer. The inside char layers also provided more space and time for DBDPO to play its flame retardant role in gaseous phases. POLYM. COMPOS., 40:986–999, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The microstructure evolution and mechanical properties under different temperature of as-cast Al-La alloys with varying La contents were investigated by X-ray diffraction (XRD), field-emission scanning electron microscope (FESEM), energy dispersive spectrometer (EDS) and tensile test (Gleeble 3500). The results revealed that the phase compositions of Al-xLa (x = 10, 15, 20) alloys were α-Al and Al 11 La 3 . Comparing with Al-10La, the mechanical properties of Al-15La and Al-20La were deteriorated due to the formation of strip-shaped and particle-shaped primary Al 11 La 3 phase respectively. The influence of Al 11 La 3 phase on tensile strength has a downward trend with the increasing temperature, and elevated temperature is more helpful to increase the plasticity of Al-La alloys with high La content. According to the tensile fracture of the three Al-La alloys at temperature range from 200 °C to 500 °C, Al-10La tended to be highly dimples driven, and dimples became larger and deeper with increasing temperature, which demonstrated a growing ability to avoid crack extension. There was a transformation from cleavages to dimples in Al-15La and Al-20La with increasing temperature, but the dimples were small and shallow indicating lower plasticity than Al-10La. [ABSTRACT FROM AUTHOR]