[en] The degradation and transformation of p-nitrophenol (PNP) was evaluated with as-prepared iron oxides (γ-FeOOH, Fe₃O₄, and α-Fe₂O₃) as catalyst. Results showed that α-Fe₂O₃ exhibited higher catalytic activity than the other two samples for reduction transformation and oxidative degradation of PNP. α-Fe₂O₃ showed higher surface-bound Fe(II) contents in the presence of oxalic acid and stronger affinity to PNP, leading to an increase in PNP reductive transformation. And α-Fe₂O₃ could effectively adsorb visible light and hinder the recombination of charge carriers, resulting in higher oxidative degradation activity. p-Aminophenol (PAP), as the main reduction transformation product of PNP, could be removed further by oxidative degradation in the reaction system itself. A possible mechanism was suggested for the comprehensive effect of PNP degradation during the reaction process.

[en] The continuous carbon fiber reinforced Polyether-ether-ketone (PEEK) prepreg tapes with the addition of carbon nanotubes (CNTs) were prepared by a wet powder impregnation process. Their electrical conductivity, thermal conductivity, the tensile properties, dynamic mechanical behavior, fracture morphology and crystallization melting behavior were investigated. The results show that, the electrical conductivity (σ), thermal conductivity (λ), tensile strength (σ _t) and interfacial adhesion of the prepreg tapes were obviously improved with the addition of CNTs. When CNT content was 1.0 wt%, the σ of CNT/CCF/PEEK prepreg tapes in the 0° direction reached a maximum value of 0.701 s cm⁻¹, which was increased 165% than that of CCF/PEEK prepreg tapes. The λ reached 1.053 W m⁻¹·K⁻¹, which was improved by 12.14%. The tensile strength was 1489 MPa, which was increased by 16.4%. The results of SEM images show that the interface adhesion between the fiber and the matrix is good. The results of DMA indicate that, the capability of deformation resistance of the prepreg tapes were further improved with the addition of CNTs. When the temperature was 280 °C, the decline rate of E′ of 1.0 wt% CNT/CCF/PEEK prepreg tapes were 3.58%. The results of DSC indicate that, the T _c of CNT/CCF/PEEK prepreg tapes moved to high temperature after adding CNTs, which indicate that CNTs played a role of heterogeneous nucleation in the PEEK matrix. (paper)

[en] The effect of two different continuous carbon fibers (CCF1 and CCF2) with different material properties on structure-properties of continuous carbon fibers reinforced polyether-ether-ketone prepreg tapes (CCF/PEEKPT) prepared by a wet powder impregnation process were investigated. The effects of fiber content on the tensile properties, dynamic mechanical behavior, crystallization melting behavior and fracture morphology of prepared prepreg tapes were performed by the dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and scanning electron microscope (SEM) etc. The results showed that, the tensile strength of CCF1/PEEKPT increased with increasing of the carbon fiber content within 50–75 wt%. Meanwhile, the tensile strength of 50–65 wt% CCF2/PEEKPT had the same change trend, but then decreased when the fiber content of composites was higher than 65 wt%. The storage modulus (E′) of composites increased with adding content of carbon fiber. The composites still maintained high deformation resistance when the temperature rose to 290 °C. Compared with pure PEEK, the crystallinity and crystallization rate of the composites both increased with the occurrence of fiber inducing PEEK crystallization, but the crystallization onset temperature, crystallization temperature and melting temperature of CCF/PEEKPT moved to low temperatures with adding of fiber content. In general, these observations suggested that CCF hindered the movement of the polymer chain segment and constrained the spherulites growth of PEEK for CCF/PEEKPT.