Solving the depth of light curing is as simple and rough as that

Curing depth in light curing is always a big problem, especially for systems with fillers. In the last issue of article

, with this method, deep light curing is no longer a problemdescribes the method of heat generation under near-infrared exposure through near-infrared dyes, which is used to trigger heat triggers to achieve deep curing. Today we introduce a
A.
H.
at the University of Upper Alsace in france
de Haute-Alsace
. Bonardi
easier way to achieve deep curing and
china
. For some basic introductions to near-infrared, please read the previous article directly to understand, we will not repeat here.method is achieved by irradiated a three-part system in near-infrared. These three components are made up of dyes
(
photosensitive agents
), iodine salt
s
(
photoinfragents
)
and compounds
(
dye regenerants
)
that are absorbed in the near-infrared region.
Bondi
compared a series of dyes and found that
Ir140
borate dyes were the most efficient, using a double iodinesort of
(4-
sopenblybenzene
)
iodine hexafluorophosphate Ar
(Ar
2
I
plus
PF
6
-
)
, the compound is
4-
dylphenylphenidate
(4-dppba)
. The mixed monoid for polymerization is a mixture of methyl acrylic hydroxypropyl
(HPMA)
,
1,4-
butyl glycol dismethyl acrylates
(1,4-BDDA)
and urethane dmethyl acrylates
(UDMA)
are mixed at a ratio of
1:1:1
.
this includes
The three-
system of IR-140
/Ar
2
I
plus
PF
6
-
/4-dppba
can obtain a high polymerization speed, and the final conversion rate of the mixed monolith is
50-60%
, resulting in a polymer surface drying. But when you remove any of the two added additives
(Ar
2
I
plus
PF
6
-
/4-dppba)
, no light polymerization reaction occurs
(
Figure
2)
.in the polymerization reaction of composite materials, fillers are often used. However,
difficult
for UV curing, as fillers can greatly affect the penetration

of UV light. But for near-infrared systems, the presence of fillers is no longer a problem. With the
IR-140
borate
/Ar
2
I
plus
PF
6
-
/4-dppba
three-part system, the polymerization speed of the system will not be significantly reduced with the addition of fillers. Interestingly, light polymerization works fine even when the filler is added to
75wt

(
Figure
3)
.the reaction principle of this three-part system is shown
4
figure. The presence of 4-dppba
system
is very important for the effective occurrence of system polymerization reaction under existing experimental conditions. The free-form polymerization of methyl acrylates in the air is a big problem because free-agents combine with oxygen to form a very stable peroxygen free-
(ROO
.
)
to abort the reaction. The
of the
4-dppba
can continue to trigger polymerization reactions through its production with peroxygen free-
(RO)
. At the same time, the degradation rate of the dye is reduced in the presence of the lysos.
4-dppba
is a good power supply that allows the dye to be regenerated
(figure

4
, step
5)
, thereby slowing the consumption of the dye.
diagram
the chemical
of photochemical reactions in the three-part system Bonardi
et al. through a series of near-infrared dyes, found the use of
IR-140
borate near-infrared dyes, and iodized salt
ar
2
The three-component combination of
I-
plus
PF
6
-
and the chemical
4-dppba
provides excellent photo-curing results under near-infrared exposure, even under a filler content system of up to
75%
. This research work provides a simple, efficient and convenient method for high filler content systems and for curing depth of photo-curing systems.
reference
Bonardi, A. H., F. Dumur, T.M. Grant, G. Noirbent, D. Gigmes, B. H. Lessard, J. P. Fouassier and J. Lalevée (2018). "High Performance Near-Infrared (NIR) Photoinitiating Systems Operating under Low Light Intensity and in The Presence of Oxygen." Macromolecules 51 (4): 1314-1324.