Calorimetric, optical and catalytic activity studies of europium chloride–polyvinyl alcohol composite system

2011 ◽  
Vol 72 (9) ◽  
pp. 1057-1065 ◽  
Author(s):  
Khaled H. Mahmoud ◽  
Zeinhom M. El-Bahy ◽  
Ahmed I. Hanafy
Keyword(s):  
Catalytic Activity ◽  
Polyvinyl Alcohol ◽  
Composite System ◽  
Europium Chloride

Interactive effects of carbon nanotube and montmorrilonite reinforcement polyvinyl alcohol composite system

2019 ◽  
Vol 26 (1) ◽  
pp. 77-89
Author(s):  
Soo‐Tueen Bee ◽  
Lee Tin Sin ◽  
Nicole Ooi Ker Qi ◽  
Chantara Thevy Ratnam ◽  
A. R. Rahmat
Keyword(s):  
Carbon Nanotube ◽  
Polyvinyl Alcohol ◽  
Composite System ◽  
Interactive Effects

scholarly journals Superior Interaction of Electron Beam Irradiation with Carbon Nanotubes Added Polyvinyl Alcohol Composite System

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4334
Author(s):  
Soo-Tueen Bee ◽  
Nicole Ooi Ker Qi ◽  
Lee Tin Sin ◽  
Hon-Meng Ng ◽  
Jun-Ven Lim ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Electron Beam ◽  
Polyvinyl Alcohol ◽  
Young’S Modulus ◽  
Electron Beam Irradiation ◽  
Composite System ◽  
Young's Modulus ◽  
Beam Irradiation ◽  
Crosslinked Networks ◽  
Adhesion Effect

This work was conducted to investigate the effect of carbon nanotube (CNT) on the mechanical-physico properties of the electron beam irradiated polyvinyl alcohol (PVOH) blends. The increasing of CNT amount up to 1.5 part per hundred resin (phr) has gradually improved tensile strength and Young’s modulus of PVOH/CNT nanocomposites due to effective interlocking effect of CNT particles in PVOH matrix, as evident in SEM observation. However, further increments of CNT, amounting up to 2 phr, has significantly decreased the tensile strength and Young’s modulus of PVOH/CNT nanocomposits due to the CNT agglomeration at higher loading level. Irradiation was found to effectively improve the tensile strength of PVOH/CNT nanocomposites by inducing the interfacial adhesion effect between CNT particles and PVOH matrix. This was further verified by the decrement values of d-spacing of the deflection peak. The increasing of CNT amounts from 0.5 phr to 1 phr has marginally induced the wavenumber of O–H stretching, which indicates the weakening of hydrogen bonding in PVOH matrix. However, further increase in CNT amounts up to 2 phr was observed to reduce the wavenumber of O–H stretching due to poor interaction effect between CNT and PVOH matrix. Electron beam irradiation was found to induce the melting temperature of all PVOH/CNT nanocomposite by inducing the crosslinked networks.

scholarly journals Screening of Supports for the Immobilization of β-Glucosidase

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Joelise de Alencar Figueira ◽  
Fernanda Furlan Gonçalves Dias ◽  
Hélia Harumi Sato ◽  
Pedro Fernandes
Keyword(s):  
Catalytic Activity ◽  
Polyvinyl Alcohol ◽  
Sol Gel ◽  
Ph Stability ◽  
Activity Profile ◽  
Michaelis Constant ◽  
Diffusion Limitations ◽  
Two Systems ◽  
Selection Of

A set of supports were screened for the immobilization of a partially purified extract of β-glucosidase from Aspergillus sp. These supports, namely, Eupergit, Amberlite, alginate, gelatin, polyvinyl alcohol- (PVA-) based matrices (Lentikats), and sol-gel, have proved effective for the implementation of some other enzyme-based processes. The initial criterion for selection of promising supports prior to further characterization relied on the retention of the catalytic activity following immobilization. Based on such criterion, where immobilization in sol-gel and in Lentikats outmatched the remaining approaches, those two systems were further characterized. Immobilization did not alter the pH/activity profile, whereas the temperature/activity profile was improved when sol-gel support was assayed. Both thermal and pH stability were improved as a result of immobilization. An increase in the apparent KM (Michaelis constant) was observed following immobilization, suggesting diffusion limitations.

scholarly journals Effect of Polyvinyl Alcohol Ligands on Supported Gold Nano-Catalysts: Morphological and Kinetics Studies

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 879
Author(s):  
Stefano Scurti ◽  
Eleonora Monti ◽  
Elena Rodríguez-Aguado ◽  
Daniele Caretti ◽  
Juan Antonio Cecilia ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Polyvinyl Alcohol ◽  
Photoelectron Spectroscopy ◽  
Catalytic Mechanism ◽  
Weight Ratio ◽  
Metal Nanoparticle ◽  
X Ray ◽  
Nano Catalysts ◽  
Supported Gold

The effect of polyvinyl alcohol (PVA) stabilizers and gold nanoparticles supported on active carbon (AuNPs/AC) was investigated in this article. Polymers with different molecular weights and hydrolysis degrees have been synthesized and used, like the stabilizing agent of Au nano-catalysts obtained by the sol-immobilization method. The reduction of 4-nitrophenol with NaBH4 has been used as a model reaction to investigate the catalytic activity of synthesized Au/AC catalysts. In addition, we report several characterization techniques such as ultraviolet-visible spectroscopy (UV-Vis), dynamic light scattering (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) in order to correlate the properties of the polymer with the metal nanoparticle size and the catalytic activity. A volcano plot was observed linking the catalytic performance with hydrolysis degree and the maximum of the curve was identified at a value of 60%. The Au:PVA-60 weight ratio was changed in order to explain how the amount of the polymer can influence catalytic properties. The effect of nitroaromatic ring substituents on the catalytic mechanism was examined by the Hammett theory. Moreover, the reusability of the catalyst was investigated, with little to no decrease in activity observed over five catalytic cycles. Morphological and kinetic studies reported in this paper reveal the effect of the PVA polymeric stabilizer properties on the size and catalytic activity of supported gold nanoparticles.

Constructing a tetraphenylethene (TPE) derivative-decorated polyvinyl alcohol (PVA)/lanthanide nanoparticle composite system for tunable luminescence

2020 ◽  
Vol 49 (17) ◽  
pp. 5539-5546
Author(s):  
Songyang Huang ◽  
Jianbin Wu ◽  
Jiale Li ◽  
Lirong Yu ◽  
Xi Wang ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Polyvinyl Alcohol ◽  
Composite System ◽  
Luminescent Properties ◽  
First Time

It is found for the first time that TPEBA-modified PVA ligand-coated lanthanide nanoparticles display tunable luminescent properties due to the established energy transfer from the TPE-based ligand (donor) to the lanthanide nanoparticles (acceptor).

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