Wang Yongliang

Preparation of Zn-Al hydrotalcite and its modification with sodium dodecyl sulfate and 2-carboxyethyl phenyl phosphinic acid

Zn-Al hydrotalcites were prepared by coprecipitation method with the Zn/Al molar ratio of 3:1, 2:1 and 1:1. Sodium dodecyl sulfate (SDS) and 2-carboxyethyl phenyl phosphinic acid (CEPPA) were adopted to modify hydrotalcite by coprecipitation method. The structure of Zn-Al hydrotalcites and the modified ones were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR) and scanning electron microscopy (SEM) coupled with energy dispersive spectrometer (EDS). XRD results indicated that the layered structure of Zn-Al hydrotalcites was influenced by the Zn/Al molar ratio. The Absorption peaks of Organic groups were observed in FT-IR Spectroscopy of SDS-LDH and CEPPA-LDH, which proved successfully synthesis of SDS modified LDH and CEPPA modified LDH. The SEM and EDS results confirmed the existence of SDS and CEPPA in the modified products, which are consistent with FT-IR results. The successful intercalation of SDS and CEPPA increased the interlayer space of LDH, which makes modified LDH promising and preferable as flame retardants in nanocomposites.

Distribution of Al 2 O 3 in PE/EVA blends and the thermal conductivity of PE/EVA/Al 2 O 3 composites

This paper aims at dispersing nanoscale Aluminium oxide (Al₂O₃) in Polyethylene/Ethylene Vinyl Acetate copolymer blends (PE/EVA) to improve the thermal conductivity of the composites. Blends of PE and EVA were prepared at different PE/EVA ratio, and PE/EVA blends with co-continuous structure were obtained. PE/EVA/Al₂O₃ composites were prepared by dispersing different amount of Al₂O₃ into co-continuous PE/EVA blends. Scanning Electron Microscopy (SEM) was used to observe the morphology of PE/EVA/Al₂O₃ composites treated by selective solution extraction. The thermal conductivities and mechanical properties of PE/EVA/Al₂O₃ composites were investigated. SEM results indicated that Al₂O₃ was observed to selectively localize in PE phase. Moreover, the selective distribution of Al₂O₃ and the co-continuous structure of the composites were helpful in improving the thermal conductivity and mechanical properties, leading to a 20.9% increase of thermal conductivity of PE/EVA/Al₂O₃ composites in comparison to that of PE/Al₂O₃ composites.

Preparation of graphite nanosheets/TiO 2 composites and photocatalytic performance

Graphite nanosheets / Titanium dioxide composites (GN/TiO₂) were fabricated via sol-gel method which use tetrabutyl titanate as Ti source and different ratio of GN/TiO₂ were prepared. The composites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The photocatalytic properties of GN/TiO₂ composites were evaluated by using Methyl orange. XRD results indicate that the composites show distinct diffraction peaks of antase-type TiO₂ and graphite. TEM results proved the uniform dispersion of TiO₂ particles on the nanosheets of GN. The ratio of GN and TiO₂ exerted significant influences on the photocatalytic properties of the composites. GN/TiO₂ composite with GN and TiO₂ ratio of 1:0.15 expressed excellent photocatalytic properties.