Preparation and catalytic properties of composites with palladium nanoparticles and poly(methacrylic acid) microspheres

Abstract

Palladium (Pd) nanoparticles with different sizes are in situ synthesized by reduction of PdCl2 with NaBH4 as reductant in the presence of poly(methacrylic acid) (PMAA)microspheres. The obtained PMAA/Pd composites are characterized by Fourier transform infrared spectra, X‐ray diffraction, and Transmission electron microscopy. The catalytic activity of the PMAA/Pd composites is investigated using a model reaction, that is, reduction of p‐nitrophenol to p‐aminophenol. The reaction shows first‐order kinetics, and the reaction rate increases with increasing reaction temperature, p‐nitrophenol concentration, and loadings of Pd nanoparticles on PMAA microspheres. The PMAA/Pd composites exhibit good stability, ascribing to the Pd nanoparticles stabilized by PMAA microspheres. POLYM. COMPOS., 35:2251–2260, 2014. © 2014 Society of Plastics Engineers

A novel poly(vinylidene fluoride) composite membrane for catalysis and separation

“…The absorptions of all the membranes are almost uniform at wavenumbers less than 1,500 cm −1 , ascribed to PVDF . Different from PVDF membrane, an additional CO stretching vibration absorption at 1,730 cm −1 appears in the PVDF/PMAA blend membrane and composite membranes, confirming that PMAA is incorporated . In addition, all the membranes show strong characteristic peaks at 840 and 1,280 cm −1 , indicating the PVDF matrixes have β‐crystalline phase .…”

“…Figure b shows the ultraviolet absorption spectra of the feed solution with reaction time. Initially ( t = 0), the feed solution shows a powerful absorption peak at 400 nm, ascribed to p ‐nitrophenol . This absorption becomes lower and lower as the reaction progresses, meaning that p ‐nitrophenol in the feed solution becomes less and less.…”

“…This absorption becomes lower and lower as the reaction progresses, meaning that p ‐nitrophenol in the feed solution becomes less and less. Meanwhile, the feed solution shows a new absorption peak at 310 nm, ascribed to p ‐aminophenol , which becomes stronger with time. Finally, the absorption peak at 400 nm has almost disappeared totally, and simultaneously the growth of the absorption peak at 310 nm has almost stopped, indicating that catalytic reaction finishes.…”

“…PMAA microspheres were prepared by the method of distillation precipitation polymerization . A mixture of MAA (2.0 g), EGDMA (2.1 g), AIBN (0.08 g), and acetonitrile (160.0 mL) was added into a 250 mL round‐bottom flask.…”

“…The metal NPs contents of the membranes were determined by firstly dissolving the metal NPs with aqua regia (HNO 3 : HCl = 1:3) and then measuring the concentration of the metal ions with the inductively coupled plasma atomic emission spectroscopy (ICP‐AES, 715‐ES, VARIAN, America) .…”