Optimization of UHMWPE/graphene nanocomposite
preparation by single‐supported Ziegler‐Natta catalytic system
Departments of Chemical Engineering, Jundi‐
Shapur University of Technology, Dezful, Iran
Mojtaba Shafiee, Jundi‐Shapur University of
Technology, Dezful, Iran.
In this study, the preparation of ultra‐high molecular weight polyethylene/graphene nanocom-
posite was carried out using single‐supported Ziegler‐Natta catalyst, and the operational condi-
tions were optimized via response surface methodology. For this purpose, the effect of 3
parameters, monomer pressure, temperature, and molar ratio of [Al] respect to [Ti] on the catalyst
productivity and molecular weight of the synthesized nanocomposite polymer, was investigated
using the Box‐Behnken experimental design at 3 levels. Monomer pressure, temperature, and
molar ratio of [Al] respect to [Ti] were considered as independent variables and catalyst
productivity and molecular weight as dependent variables. The highest catalyst productivity
and molecular weight were equal to 923 (grPE/mmolTi.h) and 2.04 (million gr/mol), respectively,
which were obtained under optimal reaction conditions: temperature of 60°C, pressure of 8 bar,
and molar ratio of 185. Finally, in order to investigate the morphology and nanoparticle dispersion
in polymer matrix, scanning electron microscope and X‐ray diffraction were used. The results
indicate the homogenous dispersion of graphene nanoparticles in polymer matrix.
graphene, polymerization, response surface methodology (RSM), UHMWPE, Ziegler‐Natta
Ultra high molecular weight poly‐ethylene (UHMWPE) is a semicrystal-
line polyolefin with a mechanical and physical properties suitable for
use in a variety of applications such as industrial, medical, and military
applications. Over the past 50 years, this polymer has been used as a
high‐strength material in the manufacture of synthetic joints,
ice surfaces (in sports such as hockey), hydraulic bearings and hydraulic
pads, wearable polymer rollers, etc. It is also used as a fiber to produce
various items such as anti‐bullet vests, parachutes, gloves resistant to
cutting, and so on. One of the main challenges of using this polymer
is its low surface hardness and tribological resistance that it has
attracted the attention of many scientists to improving the properties
of this polymer.
It is important to investigate alternative methods for tribological
performance enhancement of UHMWPE. Cross‐linking (with the help
of gamma radiation or using proxides) greatly increases the wear
but some mechanical properties such as flexibility and
fatigue resistance are reduced by cross‐linking.
Other methods of
improving the mechanical and wear properties of UHMWPE are the
use of mineral fillers such as zirconium,
and carbon nanotubes.
The production of these
composites is limited due to the need for high filler and costly.
Graphene is known as the thinnest substance in the world with a
variety of applications. Graphene has incredible properties similar to
the high thermal conductivity, mechanical properties, and electrical
conductivity. These intrinsic properties of graphene have led to its
use in various applications such as electrical appliances and reinforced
nanocomposites with electrical and thermal conductivity.
Graphene oxide (GO) is an oxidized form of graphene, laced with
oxygen containing groups. Compared with other nanostructures, GO
nanoparticles are more compatible with organic polymers.
Response surface methodology (RSM) is a collection of
mathematical and statistical techniques for empirical model building.
By careful design of experiments, the objective is to optimize a
response (output variable) which is influenced by several independent
variables (input variables). In this study, preparation of UHMWPE/
graphene nanocomposite by using single‐supported Ziegler‐Natta
catalyst via in situ polymerization method has been investigated.
Then, the optimization of operational condition to improving catalyst
productivity and molecular weight via Box‐Behnken experimental
design has been studied.
Received: 24 January 2018 Revised: 15 February 2018 Accepted: 19 February 2018
Polym Adv Technol. 2018;29:1889–1894. Copyright © 2018 John Wiley & Sons, Ltd.wileyonlinelibrary.com/journal/pat 1889