CommuniCation
1800101 (1 of 8)
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2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.mme-journal.de
A (Triphenylphosphine)Silver (I) Complex as a New
Performance Additive in Free-Radical Photopolymerization
under Air
Pauline Sautrot-Ba, Nicolas Bogliotti, Arnaud Brosseau, Julie Bourgon,
Pierre-Emmanuel Mazeran, Jacques Lalevée, Fabrice Morlet-Savary, and Davy-Louis Versace*
P. Sautrot-Ba, J. Bourgon, Dr. D.-L. Versace
Université Paris-Est Créteil (UPEC) – Institut de Chimie et des Matériaux
Paris-Est (ICMPE) UMR CNRS 7182
Systèmes Polymères Complexes
61, Avenue du Général de Gaulle, 94010 Créteil cedex, France
E-mail: versace@icmpe.cnrs.fr
Dr. N. Bogliotti, A. Brosseau
Laboratoire de Photophysique et Photochimie
Supromoléculaires et Macromoléculaires
ENS Paris-Saclay
CNRS
Université Paris-Saclay
F-94235 Cachan, France
Prof. P.-E. Mazeran
Laboratoire Roberval
CNRS
UMR 7337
Département mécanique
Sorbonne universités
Université de technologie de Compiègne
Centre de recherche
Royallieu – CS 60319 – 60203 Compiègne cedex, France
Prof. J. Lalevée, Dr. F. Morlet-Savary
Département Photochimie
Institut de Science des Matériaux de Mulhouse
IS2M-LRC 7228, 15 rue Jean Starcky – 68057 Mulhouse, France
DOI: 10.1002/mame.201800101
solvent, and the capability to tune physical
or chemical properties of the crosslinked
materials in a reduced time. However, sev-
eral limitations exist and oxygen inhibition
remains the main issue of concern.
[1]
FRP
is greatly vulnerable to oxygen mole cules
thus leading to incomplete curing and
tacky surfaces with poor mechanical prop-
erties. To understand this problem, an
idealized mechanism showing the ways
in which radicals are affected by oxygen is
described in Scheme 1. Under illumination
and in aerated conditions, the photolysis
of type I photoinitiators generates primary
initiating radicals (R•) which are scavenged
by oxygen to yield peroxyl radicals ROO•. These later radicals
are inactive toward the addition to acrylate double bounds and
tend to terminate polymerization via radical combinations.
[2–5]
Due to the industrial interest of photochemistry, alternative
approaches
[6]
that reduce this adverse reaction during the initia-
tion step have then been introduced and include inerting,
[7,8]
the
increase of light intensity or the photoinitiator concentration,
[9]
the employment of hydrogen donors and reducing agents,
[10–12]
silanes
[13]
or organoboranes,
[14]
phosphines,
[15]
the use of wax
barrier coats,
[16]
or the use of metal-derived molecules such as
germanes,
[13]
stannanes,
[13]
Ti or Zr compounds
[17,18]
which
were associated with cleavable type I photoinitiators (such as
bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide BAPO or
2,2-dimethoxy-2-phenylacetophenone (DMPA). In this later case,
a bimolecular homolytic substitution reaction (S
H
2 process) that
converts the unefficient peroxyl radicals into new radical initi-
ating species is described: this process allows the synthesis of
metal oxide nanoparticles (NPs) in a controlled manner under
light illumination. However, such a chemical route does not exist
in the fabrication of metal NPs (Ag, Au, or Cu) under air. All the
proposed synthetic strategies concern the direct photoreduction
or the photosensitized reductions of metal salts
[19–21]
or deriva-
tives—metal-functionalized PIs such as a gold–thiophene deriva-
tive
[22]
or a Ag–thioxanthone derivative
[23]
—either in solution or
in polyacrylate matrix
[24–27]
in nonaerated conditions. Indeed, the
main drawback in aerated medium stays in this case the strong
oxygen inhibition observed during the polymerization reaction.
The originality of our study deals with the use of the known
Ag(I)-derived complex
[28]
(bis[(µ-chloro)bis(triphenylphosphine)
silver (I)] stands for [Ag](PPh
3
)) acting here both as a photoiniti-
ating system—for accelerating the FRP of acrylate monomer in
Ag Nanocomposites
Unusual photochemical properties of an Ag(I)-derived complex, i.e.,
bis[(µ-chloro)bis(triphenylphosphine)silver (I)] ([Ag](PPh
3
)) are demonstrated
when used in free-radical photopolymerization reactions: i) [Ag](PPh
3
) can act
as an innovative photoinitiating system when associated with a commercial
type I photoinitiator 2,2-dimethoxy-2-phenylacetophenone to overcome
the oxygen inhibition effect during the free-radical photopolymerization of
acrylate monomers, thus accelerating the kinetics of polymerization under air;
ii) silver-based nanoparticles can be in situ generated under air, thus leading
to new antibacterial coatings which prevent the growth of Escherichia coli and
Staphylococcus aureus after few hours of incubation.
1. Introduction
For the past decade, free-radical photopolymerization (FRP)
greatly gained in practical importance in the industrial field.
[1]
Its
main benefits over the thermal process are the low cost of opera-
tion, the mild reaction conditions without the use of any harmful
Macromol. Mater. Eng. 2018, 303, 1800101