  Healable
Resins
CRG is currently developing
a self-healing version of shape memory polymer (SMP)
called Veriflex® EH. This healable SMP resin will
enable increased survivability for manned and unmanned
air vehicles, spacecraft, and habitats for space exploration
missions, automobiles, and more.
Veriflex EH is an epoxy-based
resin that will be a direct processing replacement for
current aerospace-grade epoxy resins. Veriflex EH can
be processed using vacuum-assisted resin transfer molding
(VARTM), RTM, or wet lay-up techniques. CRG is also
developing a prepreg formulation.
Veriflex EH uses two healing
mechanisms to restore up to 85% of original mechanical
performance. The first healing mechanism, shape recovery,
brings the cracked or damaged area back into intimate
physical contact. The second healing mechanism, polymer
diffusion, allows long polymer chains to diffuse across
the failure line and restore mechanical integrity. Both
healing mechanisms are thermally activated and are achieved
in less than three minutes.
Possible Applications
• Aerospace structures
• Automobiles
• Marine panels
• Composite structures
Features and Benefits
• 85% recovery
of flexural strength
• Lower cost maintenance and
repair
• Longer product life
• Increased survivability
• Tailorability for specific
applications
• Custom transition temperatures
from 14 °C to 105 °C
• Compatibility with standard
processing and manufacturing (VARTM, filament
winding, fiber placement)
Preliminary Data (material is still
in development)
| Property |
Values |
Method |
|
| Thermal |
|
|
|
Glass Transition Temperature
(Tg)
DMA,
Loss Modulus Peak |
56 °C |
133 °F |
DMA |
|
| Mechanical
(at room temperature) |
|
|
|
| Tensile Strength |
70.7 MPa |
10 Kpsi |
ASTM D638 |
| Tensile Modulus |
3030 MPa |
439 Kpsi |
ASTM D638 |
| Tensile Elongation to Break |
3.5% |
|
ASTM D638 |
| Flexural Stress |
119 MPa |
17 psi |
ASTM D790 |
| Flexural Modulus |
3590 MPa |
520 psi |
ASTM D790 |
|
| Mechanical
(30 °C above Tg) |
|
|
|
| Tensile Strength |
.242 MPa |
35 psi |
ASTM D638 |
| Tensile Modulus |
.00066 MPa |
96 psi |
ASTM D638 |
| Tensile Elongation to Break |
268% |
|
ASTM D638 |
|
| Composite Mechanical
(12-ply 3k plain weave carbon [0.90] 6) |
|
|
|
| Flexural Stress |
490 MPa |
71Kpsi |
ASTM D790 |
| Flexural Modulus |
33000 MPa |
4,786 Kpsi |
ASTM D790 |
Flexural Stress (post-failure
& healing)
85% recovery of
flexural modulus |
417 MPa |
61 Kpsi |
ASTM D790 |
Flexural Modulus (post-failure
&
healing) 78% recovery of
flexural
modulus |
26000 MPa |
3,770 Kpsi |
ASTM D790 |
|
|
