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viscosity-average-molecular-weight
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Production and characterization of UHMWPE/fumed silica nanocomposites
, Article Polymer Composites ; Volume 33, Issue 10 , 2012 , Pages 1858-1864 ; 02728397 (ISSN) ; Saremi, M. G ; Amoli, B. N ; Izadi, H ; Sharif University of Technology
Wiley
2012
Abstract
Ultrahigh-molecular-weight polyethylene (UHMWPE)/fumed silica nanocomposites were prepared via in situ polymerization using a bi-supported Ziegler-Natta catalytic system. Nanocomposites with different nanoparticle weight fractions were produced in order to investigate the effect of fumed silica on thermal and mechanical properties of UHMWPE/fumed silica nanocomposites. The viscosity average molecular weight (M) of all samples including pure UHMWPE as the reference sample and nanocomposites were measured. Scanning electron microscope (SEM) images showed the homogenous dispersion of nanoparticles throughout the UHMWPE matrix while no nanoparticle cluster has been formed. Crystallization...
Effects of nano graphene oxide as support on the product properties and performance of Ziegler-Natta catalyst in production of UHMWPE
, Article Polymers for Advanced Technologies ; Volume 26, Issue 4 , 2015 , Pages 315-321 ; 10427147 (ISSN) ; Ramazani, S. A ; Khorasheh, F ; Baghalha, M ; Bahrami, H ; Sharif University of Technology
John Wiley and Sons Ltd
2015
Abstract
The synthesis of mono- and bi-supported Ziegler-Natta catalysts using magnesium etoxide Mg(OEt)2 and graphene oxide (GO) as catalyst support for production of Ultra High Molecular Weight Polyethylene (UHMWPE) is reported in this investigation. Nano-graphene oxide was prepared by the modified Hummer's method and its structure was analyzed by XRD and FTIR indicating the presence of hydroxyl groups on graphene oxide and the formation of an exfoliated structure. The activity of TiCl4/Mg(OEt)2, TiCl4/Mg(OEt)2-GO, and TiCl4/GO catalysts in terms of grams of PE produced per mmol of Ti per hour was experimentally obtained for catalysts with different ratios of co-catalyst (triisobutylaluminium) to...
SiO 2 -covered graphene oxide nanohybrids for in situ preparation of UHMWPE/GO(SiO 2 ) nanocomposites with superior mechanical and tribological properties
, Article Journal of Applied Polymer Science ; Volume 136, Issue 31 , 2019 ; 00218995 (ISSN) ; Saadatabadi, A. R ; Kheradmand, A ; Amini, M ; Ramezanzadeh, M ; Sharif University of Technology
John Wiley and Sons Inc
2019
Abstract
The modified Hummer technique was used in the preparation of graphene oxide (GO) nanosheets, and then SiO 2 decorated GO [GO(SiO 2 )] nanosheets were synthesized via the sol–gel method. Then, ultrahigh-molecular-weight polyethylene (UHMWPE) nanocomposites loaded with 0.5, 1, 1.5, and 2 wt % of GO(SiO 2 ) were prepared using magnesium ethoxide/GO(SiO 2 )-supported Ziegler–Natta catalysts via the in situ polymerization. Morphological study of the prepared polymer powders was assessed using field-emission scanning electron microscopy, which showed that GO(SiO 2 ) nanohybrids have been uniformly dispersed and distributed into the UHMWPE matrix. Also, the neat UHMWPE and its nanocomposites were...