RELTEK
BONDiT B-45/B-45TH TEST REPORT OF PROPERTIES
NOTE: (for printable pdf version of this report, click
here)
A Study of the Physical Properties
of B-45TH Epoxy
1. Introduction
A study of the physical and mechanical
properties of B-45TH and B-45 was carried out
in order to better
understand potential applications of the two-part epoxy system.
TMA, TGA and DSC were used to study
the effect of curing method and mixing technique
on several important physical property
characteristics. Table 1 summarizes the
experiments that were performed.
Analysis of the physical properties
of B-45TH included for the resin mixed with a static
mixer1 and
by hand mix2:
Comparing the glass transition temperature of
a hand mixed Vs a static mixed sample,
- The out gassing behavior of the epoxy using
three curing methods and outgassing
under elevated operational
temperatures,
- The extent of curing reaction as a function
of curing method,
- Environmental test of 85RH / 85°C with three
curing methods,
- Moisture absorption, (hand mix)
- Oil absorption, (hand mix)
- Percent solid of hand mix epoxy compared to
a static mix,
- Contact angle relative to static mix and hand
mix,
- Joint strength relative to static mix and hand
mix.
Other tests included
- Tensile strength, (hand mix)
- Static fatigue strength, (hand mix)
- Tear strength, (hand mix)
- Velocity of sound, (hand mix)
- Thermal conductivity, (hand mix)
- Coefficient of thermal expansion, (hand mix)
- Lap shear tests on various substrates, (static
mix)
- Peel tests on various substrates, (static mix)
- Bead length Vs bead width for B-45TH dispensed
from a static mixer.
1 Static mix = parts A & B measured
2:1 by a double-barreled cartridge dispensed
with a plunger in
a hand actuated gun through a 6” helical 21 element static mixer
tube having a 1/16” exit nozzle.
2 Hand mix = parts A & B measured
in 2:1 ratio by weight and mixed by hand.
Table 1 TMA, TGA, DSC tests of B-45TH epoxy
|
Test#
|
Curing
method
|
Experiment
|
Thermal
Analysis Cycle
|
Comments
|
|
Glass
Transition Temperature
|
Determine
if there is a difference in Tg
|
All
runs
|
|
|
TgDSC1
|
cure
for 68 hrs @ RT
|
by using
different mixing methods
|
25-300°C
, 10°C/min
|
Mix
with static mixer
|
|
TgDSC2
|
cure
for 68 hrs @ RT
|
|
|
mix
by hand
|
|
CteTMA1
|
cure
for 72 hrs
|
Second
attempt to determine
|
All
runs
|
Mix
with static mixer
|
|
CteTMA2
|
cure
for 72 hrs
|
Tg
|
25-200°C,
2.5°C/min
|
Mix
by hand
|
|
Outgassing
|
Check
for outgassing of volatiles and water as a function of
curing method
|
All
runs
|
|
|
OgTGA1
|
cure
for 24 hrs @ RT
|
|
25-300°C,
10°C/min
|
cure
set 95%
|
|
OgTGA2
|
cure
for 30 min @ RT then 4 hrs at 65°C
|
|
|
cure
set 98%
|
|
OgTGA3
|
cure
for 30 min @ RT then 2 hrs at 93°C
|
|
|
cure
set 98%
|
|
Curing
Tests
|
Measure
extent of completion of curing reaction for the three curing
methods
|
|
All
runs
|
|
CtDSC1
|
cure
for 24 hrs @ RT
|
|
25-300°C,
10°C/min
|
cure
set 95%
|
|
CtDSC2
|
cure
for 30 min @ RT then 4 hrs at 65°C
|
|
|
cure
set 98%
|
|
CtDSC3
|
cure
for 30 min @ RT then 2 hrs at 93°C
|
|
|
cure
set 98%
|
|
CtDSC4
|
freshly
mixed, no cure
|
|
|
|
|
Environmental
Study(humidity
|
Determine
the amount of water absorption of the epoxy cured using
the three recommended methods
|
|
All
runs
|
|
EsTGA4
|
cure
for 24 hrs @ RT
|
|
25-300°C,
10°C/min
|
cure
set 95%
|
|
EsTGA5
|
cure
for 30 min @ RT then 4 hrs at 65°C
|
|
|
cure
set 98%
|
|
EsTGA6
|
cure
for 30 min @ TR then 2 hrs at 93°C
|
|
|
cure
set 98%
|
|
Mixing
Effects
|
Check
solids content of epoxy
|
|
All
runs
|
|
MeTGA1
|
wet
hardener
|
components
and epoxy
|
550°C,
30 min hold, 10°C/min
|
ash
hardener (wet)
|
|
MeTGA2
|
wet
resin
|
|
|
ash
resin (wet)
|
|
MeTGA3
|
freshly
mixed, no cure
|
|
|
ash
mixture (static mixer)
|
|
Me TGA4
|
freshly
mixed, no cure
|
|
|
ash
mixture (hand mix)
|
|
Contact
Angle
|
Determine
the difference in surface
|
All
runs: no thermal analysis was performed
The
contact angle geoniometer was used for measuring the contact
angle for the epoxy
|
|
|
Series
Cas1,2
|
Cured
for 96 hrs @ RT
|
energy
of static and hand mixed epoxy was performed
|
mixed
20 samples
|
|
Series
Cah1,2
|
Cured
for 96 hrs @ RT
|
Also,
difference between epoxy side exposed to air during curing
vs unexposed side
|
hand
mixed 20 samples
|
|
Joint
Strength
|
|
All
runs: no thermal analysis was performed A Chatillon joint
strength machine was used
|
|
|
Series
Jss1,2
|
Cured
for72 hrs @ RT
|
Determine
if the joint strength from a static mixed vs a hand mixed
sample population are comparable
|
|
static
mixed 20 samples
|
|
Series
Jsh1,2
|
Cured
for 72 hrs @ RT
|
|
|
hand
mixed 20 samples
|
|
|
|
|
|
|
2. Glass Transition by TMA Method
The glass
transition temperature was not apparent in either
the epoxy that was
hand mixed or sample that was mixed using
a static mixer by analyzing with the DSC.
The TMA was then
used to determine the Tg for the two samples.
Theoretically,
the glass
transition temperature should be approximately 60°C.
Expanding the graphs from 40°C to 80°C did reveal that the Tg for the static mixed
sample is 64.93°C and the Tg for the hand mixed sample is 65.02°C.
These values
are in agreement with the theoretical Tg.
The difference in Tg between the two
samples is negligible.
Figure 1 Glass Transmission temperature comparison - Hand Mix vs.
Static Mixer Method
- Outgassing
Thermo gravimetric Analysis (TGA) was used for
the outgassing study.
The initial outgassing study was performed on un-cured
material from room temperature
to 300°C at a rate of 10°C/min. This scan determines the amount of outgassing during
cure as a function of weight loss. At
60°C, the weight loss due to outgassing is
only
0.149%. Up to 220°C,
were curing appears to end and before degradation, the total
weight
loss is 7.225%.
Figure 2 Outgassing
|
