Structural Characterization of ZnO/AC Composite Prepared from Spent Catalyst of Vinyl Acetate Synthesis

2012 ◽  
Vol 518-523 ◽  
pp. 3483-3487
Author(s):  
Wen Wen Qu ◽  
Wen Jin ◽  
Jin Hui Peng ◽  
Shu Yang

ZnO/AC composite was prepared from spent catalyst of vinyl acetate synthesis by using conventional thermal treatment under CO2 atmosphere. The final composite was obtained with the operating conditions of activation temperature of 950°C, activation time of 120min and the CO2 flow rate of 600ml/min. The structure and surface properties of the ZnO/AC composite were observed and characterized by scanning electron microscope (SEM-EDX), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and the UV diffuse reflectance spectra. It was found that the zinc acetate present in the spent catalyst is transformed to zinc oxide (ZnO) after thermal treatment. ZnO particles were well adhered and uniformly distributed onto the carbon surface, forming ZnO/AC composite. The thermal treatment of the spent catalyst gives rise to a material with excellent adsorptive and photocatalytic properties.

2008 ◽  
Vol 8 (4) ◽  
pp. 1707-1713
Author(s):  
Samira Benali ◽  
Sophie Peeterbroeck ◽  
Jérôme Larrieu ◽  
Fabrice Laffineur ◽  
Jean-Jacques Pireaux ◽  
...  

The influence of the chemical structure of alkylammonium organo-modifying montmorillonite clays on the ability to form nanocomposites by melt blending, depending on the processing temperature and the organoclay thermal treatment, has been investigated. On one side chlorinated polyethylene/Cloisite®30B (nano)composite has been prepared by melt intercalation at 175 °C and its wide angle X-ray diffraction pattern revealed that the peak characteristic of the interlayer spacing of the organoclay was shifted to lower d-spacing, indicating a collapse of the organoclay structure. On the other side, (nano)composites based on ethylene-vinyl acetate copolymer/Cloisite®30B have been prepared by melt intercalation at 140 °C. At this temperature, exfoliation was observed with the as-received organoclay while the same organo-modified clay, simply dried at 180 °C for 2 hours, induced again the formation of a composite with a collapsed structure. The effect of the Cloisite®30B thermal treatment on the morphology and mechanical properties of ethylene-vinyl acetate–based (nano)composites was investigated using wide angle X-ray diffraction and tensile tests. In order to shed some light on the origin of this clay interlayer collapse, organoclay modified with various ammonium cations bearing long alkyl chains with different amounts of unsaturations were studied using wide angle X-ray diffraction and X-ray photoelectron spectroscopy before and after thermal treatment at 180 °C for 2 hours. Isothermal thermogravimetric analysis of all organoclays was also investigated. The layers collapse effect is discussed depending upon the level of unsatured hydrocarbon present in the organic surfactant.


2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Mahmoud Goodarz Naseri ◽  
Elias B. Saion ◽  
Ahmad Kamali

This study reports the simple synthesis of MFe2O4 (where M=Zn, Mn, and Co) nanoparticles by a thermal treatment method, followed by calcination at various temperatures from 723 to 873 K. Poly(vinyl pyrrolidone) (PVP) was used as a capping agent to stabilize the particles and prevent them from agglomeration. The characterization studies were conducted by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average particle sizes were obtained by TEM images, which were in good agreement with the XRD results. Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of metal oxide bands for all the calcined samples. Magnetic properties were demonstrated by a vibrating sample magnetometer (VSM), which displayed that the calcined samples exhibited superparamagnetic and ferromagnetic behaviors.


2011 ◽  
Vol 335-336 ◽  
pp. 3-11
Author(s):  
Jun Wang

The nanocomposites of poly(vinyl acetate)/montmorillonite (PVAc/MMT) were prepared using vinyl acetate and organically modified alkaline calcium base montmorillonite (MMT) by in situ emulsion copolymerization. The organic modification was acrylic acid including terminal reactive vinylic group. The samples were characterized using fourier transformation infrared spectroscopy (FT-IR), X-ray diffraction (XRD). Thermal properties of the PVAc/MMT films were studied by thermogravimetric (TG) and differential scanning calorimetric (DSC). The FT-IR results indicated that the vinyl group on the surface of the vinyl MMT nanoparticles had been successfully copolymerized with vinyl acetate. The XRD results demonstrated that the MMT was exfoliated during polymerization. The exfoliated PVAc/MMT nanocomposites showed a lower glass transition temperature (Tg) and a worse thermal stability compared with the pure PVAc. However, bonding power of the nanocomposite latex of PVAc/MMT was improved due to the strong interaction between silica nanoparticles and polymer matrix via covalent bonds.


2008 ◽  
Vol 92 (1-2) ◽  
pp. 79-85 ◽  
Author(s):  
Wei Li ◽  
Jinghui Peng ◽  
Libo Zhang ◽  
Zebiao Zhang ◽  
Lei Li ◽  
...  

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Badia Imene Cherifi ◽  
Mohammed Belbachir ◽  
Abdelkader Rahmouni

AbstractIn this work, the green polymerization of vinyl acetate is carried out by a new method which consists in the use of clay called Maghnite-Na+ as an ecological catalyst, non-toxic, inexpensive and recyclable by simple filtration. X-ray diffraction (XRD) showed that Maghnite-Na+ is successfully obtained after cationic treatment (sodium) on raw Maghnite. It is an effective alternative to replace toxic catalysts such as benzoyl peroxide (BPO) and Azobisisobutyronitrile (AIBN) which are mostly used during the synthesis of polyvinyl acetate (PVAc) making the polymerization reaction less problematic for the environment. The synthesis reaction is less energetic by the use of recycled polyurethane as container for the reaction mixture and which is considered as a renewable material and a good thermal insulator which maintains the temperature at 0 °C for 6 h. The reaction in bulk is also preferred to avoid the use of a solvent and therefore to stay in the context of green chemistry. In these conditions, the structure of obtained polymer is established by Nuclear Magnetic Resonance Spectroscopy 1H NMR and 13C NMR. Infrared spectroscopy (FT-IR) is also used to confirm the structure of PVAc. Thermogravimetric analysis (TGA) showed that it is thermally stable and it starts to degrade from 330 °C while Differential Scanning calorimetry (DSC) shows that this polymer has a glass transition temperature (Tg  = 50 °C). The composition in PVAc/Maghnite-Na+ (7 wt% of catalyst) is the most tensile resistant with a force of 182 N and a maximum stress of 73.16 MPa, the most flexible (E  = 955 MPa) and the most ductile (εr  = 768%).


2021 ◽  
Vol 15 (2) ◽  
pp. 183-190
Author(s):  
Badia Imene Cherifi ◽  
◽  
Mohammed Belbachir ◽  
Souad Bennabi ◽  
◽  
...  

In this work, the green polymerization of vinyl acetate is carried out by a new method which consists in the use of clay called Maghnite-Na+ as an ecological catalyst, non-toxic, inexpensive and recyclable by a simple filtration. X-ray diffraction and scanning electron microscopy showed that Maghnite-Na+ is successfully obtained after cationic treatment (sodium) on crude maghnite. It is an effective alternative to replace toxic catalysts such as benzoyl peroxide and azobisisobutyronitrile which are mostly used during the synthesis of polyvinyl acetate (PVAc) making the polymerization reaction less problematic for the environment. The synthesis reaction is less energetic by the use of recycled polyurethane as a container for the reaction mixture and is considered as a renewable material and a good thermal insulator maintaining the temperature of 273 K for 6 h. The reaction in bulk is also preferred to avoid the use of a solvent and therefore to stay in the context of green chemistry. In these conditions, the structure of obtained polymer is established by 1H NMR and 13C NMR. Infrared spectroscopy (FT-IR) was also used to confirm the structure of PVAc. Thermogravimetric analysis showed that it is thermally stable and starts to degrade at 603 K while differential scanning calorimetry showed that this polymer has a glass transition temperature Tg of 323 K.


2017 ◽  
Vol 36 (2) ◽  
pp. 107-112 ◽  
Author(s):  
Sousan Gholamrezaei ◽  
Masoud Salavati-Niasari ◽  
Hassan Hadadzadeh ◽  
Mohammad Taghi Behnamfar

AbstractCo3O4 nanostructures have been synthesized via a hydrothermal-assisted thermal treatment process. A new complex formulated as [Co(py)2(H2O)2(NO3)2] was synthesized, and then used to prepare Co3O4 nanostructures. Cubic phase of spinel Co3O4 nanostructures with particle size of about 39 nm could be produced after calcination of the Co(OH)2 materials prepared with hydrothermal method at 160 °C for 15 h. Using of inorganic precursors decreased the time and temperature of Co3O4 preparation. The effect of pH on the morphology of the product s synthesized by hydrothermal reactions was investigated. It was found that the best morphology was achieved on pH=8, where was not prepared any precipitation. In this method, we could decrease the reaction temperature in synthetic rout to fabricate Co3O4 nanostructures. Nanostructures were characterized by SEM, TEM, X-ray diffraction (XRD), UV–visible, Fourier transformed infrared (FT-IR) spectroscopy and Nuclear magnetic resonance (1H-NMR).


2014 ◽  
Vol 92 (7) ◽  
pp. 1249-1256 ◽  
Author(s):  
Xinhui Duan ◽  
Zebiao Zhang ◽  
C. Srinivasakannan ◽  
Fei Wang ◽  
Jinsheng Liang

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