Acrylic pressure-sensitive adhesives with nanodiamonds and acid–base
dependence of the pressure-sensitive adhesive properties
Kota Mizutani, Chizuru Hongo, Takuya Matsumoto, Takashi Nishino
Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokko,
Nada Kobe 657-8501, Japan
Correspondence to: T. Nishino (E -mail: email@example.com)
A high performance and functional properties in pressure-sensitive adhesives (PSAs) are attractive in fundamental and indus-
trial fields. To control the performance of PSAs, nanofillers have been loaded into them. In this study, we focused on composites of acrylic
PSAs and nanodiamonds (NDs). The loaded NDs reinforced the mechanical properties and increased the performance of the PSAs. NDs
in a PSA formed a network structure. In this study, we revealed that the acidic–basic state was a key factor in the control of the dispersion
of the NDs. When a PSA emulsions and ND aqueous dispersion was mixed under basic conditions, the composites demonstrated higher
PSA properties (tack, holding, and peeling strength). We investigated the effect of the ND loading on the PSA properties from the
viewpoints of the nanostructure and acid–base interactions.
2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46349.
adhesives; colloids; composites; emulsion polymerization; mechanical properties
Received 13 December 2017; accepted 7 February 2018
In the fields of electronic devices, pharmaceuticals, packaging,
labels, and cosmetics, pressure-sensitive adhesives (PSAs) have
attracted much attention from the viewpoints of utility, cost,
PSAs adhere solid substrates, such as metals or
resins, with little contact pressure and a short contact time. In
PSAs as adhesive products, various adhesive properties are
required. Three major properties, tack, holding time, and peel-
ing force, are of particular importance for the evaluation of
To access these desired properties, the control of the
molecular weight and crosslinking density, various modifica-
tions of base polymers, and the loading of additives such as
tackifiers and inorganic fillers have been investigated.
It is often
the case that the phase separation and agglomeration of addi-
tives lead to mechanical and functional defects.
Thus, in the
cases of loading additives, the dispersion is a key factor contrib-
uting to the high performance of PSAs. In addition improve-
ments in the intrinsic performance, other functional properties
are required for industrial products; for example, transmittance,
insulation resistance, electronic conductivity, and thermal con-
These functional properties are indispensable in
electronic devices and displays. Moreover, PSAs obtained from
water-in-oil emulsions are attractive non–volatile organic com-
pound materials from the viewpoint of environmental
Researchers have attempted to incorporate numerous inorganic
nanofillers into PSAs; they have reported the reinforcement and
functionalization of these nanocomposites for several deca-
Carbon nanofillers, such as carbon nanotubes
possess excellent mechanical, electrochemical,
and thermal properties. Nanodiamonds (NDs) have been pro-
duced by the detonation method, and they appear to be nano-
sized diamonds with a diamond core and a graphitelike
Therefore, NDs show superior mechanical properties
and a k originating from diamonds, which possess the highest
modulus and ks in natural minerals. In addition, their high
wear resistance, hardness, and biocompatibility are also been
The surfaces of NDs contain various hydro-
philic functional groups, including carboxyl, hydroxyl, and ether
groups, and so, NDs are obtained as aqueous dispersions.
In the case of nanocomposites with hydrophobic polymers, the
preparation methods and dispersion of ND fillers in polymer
matrixes control their performance.
Herein, we focused on the PSA properties and morphology of
polyacrylate–ND nanocomposites and the interactions between
the NDs and polyacrylates. We used two types of polyacrylates;
one was poly(n-butyl acrylate–acrylic acid) [P(BA–AA)], and
the other was poly(n-butyl acrylate–glycidyl methacrylate)
[P(BA–GMA)]. Both polymers are widely accepted as conven-
tional PSA matrixes.
The nanocomposites were prepared by
Additional Supporting Information may be found in the online version of this article.
2018 Wiley Periodicals, Inc.
J. APPL. POLYM. SCI. 2018, DOI: 10.1002/APP.46349
46349 (1 of 8)