Received: 30 September 2017 Revised: 22 December 2017 Accepted article published: 3 January 2018 Published online in Wiley Online Library: 23 February 2018
(wileyonlinelibrary.com) DOI 10.1002/pi.5529
Synthesis of nanoparticle-immobilized
antioxidants and their antioxidative
performances in polymer matrices: a review
Antioxidants are used to improve the thermo-oxidative stability of polymers during processing and to prolong the service life
of polymer materials. Immobilizing antioxidants onto nanoparticles is one of the approaches for reducing their physical losses.
Research on the design, synthesis and application of nanoparticle-immobilized antioxidants is reviewed in this article. These
kinds of ‘nano-antioxidants’ reveal good resistance against extraction and show good antioxidative eﬃciency during long-term
thermal aging, and therefore will have great potential in practical use for improving the stability of polymer materials.
© 2018 Society of Chemical Industry
Keywords: antioxidants; immobilization; nanoparticles; antioxidative eﬃciency
Polymer degradation is inevitable during processing, storage and
service, which leads to the deterioration of polymer performances.
Additives such as antioxidants and light stabilizers are usually
added into polymers to extend their service life by maintaining
their performances. However, low-molecular-weight antioxidants
have poor resistance to migration and extraction.
high-molecular-weight antioxidants are nowadays commercially
available, it has been found that they still suﬀer from physical
losses by leaching out during processing and service under aggres-
sive conditions in cases such as hot water pipes, geomembranes,
food packaging, etc.
One of the approaches for reducing the physical losses of antiox-
idants is to covalently graft them onto the backbone of polymer
chains. Kim and Oh
reported polymer-bound antioxidants pre-
pared by melt-grafting of antioxidants bearing maleimide onto
low-molecular-weight polyethylene and achieved good stability
against thermal oxidation. Xue et al.
synthesized a series of poly-
meric antioxidants via ring-opening metathesis polymerization,
which showed high antioxidant ability in polypropylene (PP). Shi
prepared a reactive antioxidant and grafted it onto the
backbones of polyamide 6 by reactive extrusion. It was found
that the equilibrium migration concentration and the diﬀusiv-
ity value of the grafted antioxidant were much lower than those
245 (a commercial antioxidant) in the polyamide
6 matrix. Recently, Manteghi et al.
reported a way of cova-
lently immobilizing phenolic antioxidants on ethylene copoly-
mers. The resulting polymer-bound antioxidants exhibited good
antioxidative ability and signiﬁcantly lower levels of migration
in a PP matrix. Xie et al.
anchored a phenolic antioxidant on
-cyclodextrin by the linkage of isophorone diisocyanate and
obtained a star-shaped macromolecular antioxidant with an aver-
age molecular weight of 4.03 × 10
. The macromolecular
antioxidant exhibited good antioxidative eﬃciency and extraction
resistance in natural rubber (NR).
Another way to prevent the physical loss of antioxidants is
to immobilize them onto nanoparticles. Nanoparticles such
as nanosilica, carbon nanotubes (CNTs) and graphene oxide
(GO) are often added to polymers to enhance their mechani-
cal, thermal and electrical properties. Comparing to traditional
stabilizers, nanoparticles have large size and thus are hard to
migrate or be extracted from polymer matrices. In the last decade,
much research has been carried out to design and synthesize
nanoparticle-immobilized antioxidants (NP-AOs) and to investi-
gate their performances in polymers. It has been found that these
so-called ‘nano-antioxidants’ exhibit good resistance to migration
and are promising long-term stabilizers.
Nanosilica is a type of inorganic ﬁller widely used in polymer
materials to improve their performances. It is odorless, tasteless
and non-toxic, and therefore it can serve as supporting mate-
rial of biosensors, antibodies and catalysts.
large speciﬁc surface area covered with numerous silanol (Si—OH)
groups and good thermal stability, nanosilica has also been stud-
ied as a support for antioxidants over the past 20 years.
Correspondence to: P Liu or M Yang, Beijing National Laboratory for
Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences,
Beijing 100190, PR China. E-mail: email@example.com (Liu); firstname.lastname@example.org
a Beijing National Laboratory for Molecular Sciences, Institute of Chemistry,
Chinese Academy of Sciences, Beijing, PR China
b University of Chinese Academy of Sciences, Beijing, PR China
Polym Int 2018; 67: 356–373 www.soci.org © 2018 Society of Chemical Industry