Production and characterization of UHMWPE/fumed silica nanocomposites

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 behavior of nanocomposites was investigated by differential scanning calorimetry (DSC), which showed a slight increase in melting temperature by enhancing the nanoparticle concentration while no significant change was observed in the crystallization temperature as the fumed silica concentration enhanced. The improvement in all thermal stability parameters was recorded by thermogravimetric analysis (TGA). Besides, via tensile testing, it was confirmed that addition of nanoparticles caused considerable improvement in such mechanical properties as Young's modulus, yield stress, and tensile strength of samples while the elongation at break declined by addition of more nanoparticles. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

Preparation and investigation of tribological properties of ultra-high molecular weight polyethylene (UHMWPE)/graphene oxide

“…The preparation of catalyst was carried out according to the method developed by our group . Pristine graphite powder was dried by heating for 6 h at 200°C under vacuum.…”

“…Ultra‐high molecular weight polyethylene (UHMWPE) is one of the thermoplastic high‐density polyethylene groups that have been at the focus of many researchers and of great use, especially in artificial bodies, because of its extraordinary properties such as high strength and stiffness, good fatigue, and appropriate wear characteristics …”

Optimization of UHMWPE/Graphene Nanocomposite Processing using Ziegler-Natta Catalytic System via Response Surface Methodology

“…The details of the catalyst complex synthesis and the corresponding mechanism are presented in our previous reports [2,3,19,20] . However, as would be discussed further, chemical bonding of the catalyst to graphene surface is one of the advantages of our method, which resulted in homogenous dispersion of nanosheets throughout the polymer matrix.…”

“…The viscosity average molecular weight (M w ) of the synthesized polyethylene was determined by the MarkHouwink equation [3]: these parameters at three levels, i.e., polymerization temperatures (50, 60, and 70 C), monomer pressures (4, 6, and 8 bar), and [Al]=[Ti] molar ratio (176, 318, and 460) was used to determine the optimal recipe in preparation of UHMWPE nanocomposites. Box-Behnken experimental design has been established using Design Expert software (7.0 trial version).…”

“…Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions INTRODUCTION Ultrahigh molecular weight polyethylene (UHMWPE), is a unique polymer with outstanding physical and mechanical properties (i.e., high strength and stiffness, good fatigue, and wear characteristics), and is widely used in joint replacement prostheses in the human body [1][2][3][4] . However, due to the low surface hardness and poor wear resistance of the polymer, wear particles lead to osteolysis.…”