Hybrid
systems were prepared at different ratios of acrylate and
epoxy and photoinitiator content, as shown inTable 1 . Throughout the remainder of the manuscript,
each mixture will be denoted as xAyE: A corresponds to the acrylate portion added at x wt % and E corresponds to the epoxy portion at a loading of y wt %. The loading of the cationic photoinitiator (TAS)
was double that of the radical photoinitiator (HMPP), due to the dilution
of TAS in propylene carbonate at 50 wt %. The photoinitiator concentration
presented in subsequent figures represents the total wt % contributed
by both photoinitiators (HMPP and TAS).
Films were
prepared with a thickness of 50 μm on glass and
metal panels to investigate the extent of polymerization and optical
properties of the films. All mixtures were vigorously stirred by magnetic
agitation prior to each application to ensure uniform mixing, and
all products were applied using a calibrated four-sided applicator
(BYK Gardner, Columbia) at a speed of 3 m/min. For UV-curing, a medium
pressure mercury lamp (Ayotte Techno-Gaz Inc., Canada) mounted over
a conveyor belt was employed. Polymerization of all films was carried
out under air and at room temperature. The intensity of the lamp was
fixed at 100%, resulting in an intensity of 500 mW/cm2 and
an energy dose of 450 mJ/cm2 at 5 m/min (conveyor speed)
in the UV-A region (from 315 to 400 nm). Irradiation intensity was
measured using a UV radiometer (Power Puck II, Electronic Instrumentation
and Technology, Inc.).
systems were prepared at different ratios of acrylate and
epoxy and photoinitiator content, as shown in
each mixture will be denoted as xAyE: A corresponds to the acrylate portion added at x wt % and E corresponds to the epoxy portion at a loading of y wt %. The loading of the cationic photoinitiator (TAS)
was double that of the radical photoinitiator (HMPP), due to the dilution
of TAS in propylene carbonate at 50 wt %. The photoinitiator concentration
presented in subsequent figures represents the total wt % contributed
by both photoinitiators (HMPP and TAS).
Films were
prepared with a thickness of 50 μm on glass and
metal panels to investigate the extent of polymerization and optical
properties of the films. All mixtures were vigorously stirred by magnetic
agitation prior to each application to ensure uniform mixing, and
all products were applied using a calibrated four-sided applicator
(BYK Gardner, Columbia) at a speed of 3 m/min. For UV-curing, a medium
pressure mercury lamp (Ayotte Techno-Gaz Inc., Canada) mounted over
a conveyor belt was employed. Polymerization of all films was carried
out under air and at room temperature. The intensity of the lamp was
fixed at 100%, resulting in an intensity of 500 mW/cm2 and
an energy dose of 450 mJ/cm2 at 5 m/min (conveyor speed)
in the UV-A region (from 315 to 400 nm). Irradiation intensity was
measured using a UV radiometer (Power Puck II, Electronic Instrumentation
and Technology, Inc.).
