scholarly journals Control of molecular weight and polydispersity in polyethylene/needle-like shaped clay nanocomposites obtained by in situ polymerization with metallocene catalysts

2016 ◽  
Vol 75 ◽  
pp. 125-141 ◽  
Author(s):  
Manuel Herrero ◽  
Karina Núñez ◽  
Raúl Gallego ◽  
Juan Carlos Merino ◽  
José María Pastor
Keyword(s):  
Molecular Weight ◽  
In Situ Polymerization ◽  
Clay Nanocomposites ◽  
Metallocene Catalysts

Preparation and Properties of the Polystyrene/Alumina Nanocomposites

2012 ◽  
Vol 557-559 ◽  
pp. 519-522
Author(s):  
Xu Man Wang ◽  
Cai Ning Zhang
Keyword(s):  
Molecular Weight ◽  
Thermal Resistance ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
In Situ Polymerization ◽  
Average Molecular Weight ◽  
Experimental Results ◽  
Solvent Resistance ◽  
Silane Coupling

Silane coupling agent KH-570 was applied to modify the surface capability of the alumina (Al2O3). The modified Al2O3were dispersed in styrene. The in-situ polymerization was used to prepare the polystyrene/alumina (PS/Al2O3) composites, in which azodiisobutyronitrile (AIBN) was used as initiator. FTIR, DSC and TG were applied to characterize the prepared composites. The solvent resistance, thermal resistance of the composites and the average molecular weight of PS in PS/Al2O3nanocomposites were studied. The experimental results demonstrated that the solvent resistance of PS/Al2O3nanocomposites was improved by the adding of Al2O3nanoparticles. The thermal resistance of the composites increased with the increasing of the Al2O3content. Meanwhile, the molecular weight of PS in the composites increased with the increasing of the Al2O3content.

A study on the kinetics and thermal properties of polystyrene/diatomite nanocomposites prepared via in situ ATRP

2018 ◽  
Vol 33 (2) ◽  
pp. 180-197 ◽  
Author(s):  
Khezrollah Khezri ◽  
Yousef Fazli
Keyword(s):  
Molecular Weight ◽  
In Situ Polymerization ◽  
Structural Characteristics ◽  
Nitrogen Adsorption ◽  
Linear Increase ◽  
Size Exclusion ◽  
Scanning Calorimetry ◽  
Morphological Studies ◽  
Exclusion Chromatography

Pristine mesoporous diatomite was employed to prepare polystyrene/diatomite composites. Diatomite platelets were used for in situ polymerization of styrene by atom transfer radical polymerization to synthesize tailor-made polystyrene nanocomposites. X-Ray fluorescence spectrometer analysis and thermogravimetric analysis (TGA) were employed for evaluating some inherent properties of pristine diatomite platelets. Nitrogen adsorption/desorption isotherm is applied to examine surface area and structural characteristics of the diatomite platelets. Evaluation of pore size distribution and morphological studies were also performed by scanning and transmission electron microscopy. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography, respectively. Linear increase of ln ( M0/M) with time for all the samples shows that polymerization proceeds in a living manner. Addition of 3 wt% pristine mesoporous diatomite leads to an increase of conversion from 72% to 89%. Molecular weight of polystyrene chains increases from 11,326 g mol−1 to 14134 g mol−1 with the addition of 3 wt% pristine mesoporous diatomite; however, polydispersity index values increases from 1.13 to 1.38. Increasing thermal stability of the nanocomposites is demonstrated by TGA. Differential scanning calorimetry shows an increase in glass transition temperature from 81.9°C to 87.1°C by adding 3 wt% of mesoporous diatomite platelets.

scholarly journals Polytetrahydrofuran/Clay Nanocomposites by In Situ Polymerization and “Click” Chemistry Processes

2008 ◽  
Vol 41 (16) ◽  
pp. 6035-6040 ◽  
Author(s):  
Mehmet Atilla Tasdelen ◽  
Wim Van Camp ◽  
Eric Goethals ◽  
Philippe Dubois ◽  
Filip Du Prez ◽  
...  
Keyword(s):  
Click Chemistry ◽  
In Situ Polymerization ◽  
Clay Nanocomposites

In-situ Polymerization of Olefins on Nanoparticles or Fibers by Metallocene Catalysts

2008 ◽  
Vol 48 (1-4) ◽  
pp. 84-90 ◽  
Author(s):  
W. Kaminsky ◽  
A. Funck ◽  
C. Klinke
Keyword(s):  
In Situ Polymerization ◽  
Metallocene Catalysts

In situ polymerization of polyethylene/clay nanocomposites using a novel clay-supported Ziegler-Natta catalyst

2009 ◽  
Vol 30 (10) ◽  
pp. 1388-1393 ◽  
Author(s):  
Ahmad Ramazani ◽  
Fahimeh Tavakolzadeh ◽  
Hossein Baniasadi
Keyword(s):  
In Situ Polymerization ◽  
Clay Nanocomposites ◽  
Natta Catalyst ◽  
Ziegler Natta Catalyst

Irradiation of poly(vinyl ester)/clay nanocomposites

2017 ◽  
Vol 52 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Ahmad Mohaddespour ◽  
Seyed J Ahmadi ◽  
Hossein Abolghassemi ◽  
Seyed M Mahjoub ◽  
Saeid Atashrouz
Keyword(s):  
Vinyl Ester ◽  
In Situ Polymerization ◽  
Surface Hardness ◽  
Clay Nanocomposites ◽  
Mechanical And Thermal Properties ◽  
X Ray Diffraction ◽  
Transition Electron Microscopy ◽  
Organically Modified ◽  
Polymerization Method

The effect of electron beam irradiation on pristine poly(vinyl ester) and cured poly(vinyl ester)/clay nanocomposite with different clay contents is studied at irradiation doses ranging from 100 to 1000 kGy at room temperature. Poly(vinyl ester)/clay nanocomposites were prepared with different amounts of organically modified montmorillonite (1, 3, and 5 wt.%) by in situ polymerization method. Morphology properties of synthesized nanocomposites were studied by X-ray diffraction and transition electron microscopy. The irradiation dose up to 500 kGy yields an increase in Young’s modulus and tensile strength of nanocomposites while further irradiation deteriorates the mechanical strength of samples. Irradiation has no considerable influence on the surface hardness of synthesized nanocomposites. Thermogravimetric analysis results reveal the thermal stability of poly(vinyl ester), and its nanocomposites is improved with irradiation up to 500 kGy. However, similar to mechanical perdition at 1000 kGy irradiation, thermal resistance of nanocomposites decreases. The enhancement in mechanical and thermal properties of synthesized nanocomposites is attributed to the cross-linking effect as bonds can be formed directly between the neighbouring chains.

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