This document discusses using supramolecular chemistry to develop a one-component epoxy system that can cure quickly at low temperatures while maintaining stability at room temperature. Photoinitiation and redox initiation are used to generate super acids from onium salts to catalyze the polymerization. Monomer design and crown ethers are shown to control the cationic ring-opening polymerization kinetics. Rheology experiments demonstrate the kinetic effects of crown ethers of different sizes on the curing reaction. Future work aims to further study epoxy blends and determine complexes using NMR.

1. Supramolecular Arrest and Activation
for the Network formation of Acid
Catalyzed Epoxy Polymerization
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu
Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute

2. Motivation
• Epoxy network formation triggered by
– Hardening Agent
– Acid generation with UV
• Develop a one component system that cures
quickly at low temperatures yet has RT stability
– Supramolecular chemistry
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu

3. System
• Super Acid Generation by Onium Salts
– Photo-initiation
– Redox-initiation
• Polymerizations monitored by
– Optical Pyrometry
– Rheology
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu
Ar2I+
MtXn
-
h
Ar2I+
MtXn
-
* ArI+
MtXn
-
+ Ar
Ar+
MtXn
-
+ ArI
. .
HMtXn
k1

4. 10
30
50
70
90
110
130
150
170
190
0 20 40 60 80 100 120 140 160
Temperature(oC)
Irradiation Time (s)
O
O
OO
1M%
O
O
O
O
O O
O
O
O
O
O
O
OO
O
2620 mJ/cm2
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu
3,4-epoxycyclohexylmethyl
3’,4’-epoxycyclohexane
carboxylate

5. Ring Opening Polymerizations
• Highly exothermic due to ring strain
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu
10
30
50
70
90
110
130
150
170
190
0 20 40 60 80 100
Time (s)
Temperature(o
C)
O
O
O
O
O
2700 mJ/cm2
I+
O n-C11H23
SbF6
-

6. Supramolecular Arrest though Monomer Design
• Alkyl glycidal ethers have long induction periods
• Increasing coordination by the monomer
O
O
+
O
O
O
O
H
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu
Neopentlyglycoldicly
cidyl ether Trimethylolpropane
triglycidyl ether
Methyl
glycidyl
ether

7. Dynamic Shear Rheology
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu
G* = G’ + iG’’
δ = atan(G’’/G’)

8. Dynamic and Steady Shear Experiments
Dynamic
Steady
Model Compound
Dipropylene Glycol Dyglicidal Ether
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu

9. Modifying Reaction Kinetics with Crown Ethers
18-crown-6
1050 mJ/cm2
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu

10. 10
30
50
70
90
110
130
150
170
190
0 20 40 60 80 100 120 140 160
Temperature(oC)
Irradiation Time (s)
O
O
OO
1M%
O
O
O
O
O O
O
O
O
O
O
O
OO
O
2620 mJ/cm2
Modifying Reaction Kinetics with Crown Ethers
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu

11. Matthew J. Spencer, James V. Crivello, Chang Y. Ryu
Dynamic Shear Experiments with 15-Crown-5 at 40C
Moles IOC-11 / moles Monomer ~ 0.002

12. The Supramolecular Complex
• 2,6-di-t-butylpyridine is a ‘proton trap’, but will not neutralize larger
species like an tertiary oxonium ion
• Crown ethers serve as a
‘molecular ruler’ for acid species
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu
Polyether ring Pore Size (A)
12-crown-4 1.2-1.5
15-crown-5 1.7-2.2
18-crown-6 2.6-3.2

13. Summary & Future Work
• Development of one component epoxy system
– Long working life and low temperature cure
• Control of cationic ring opening polymerizations
– Monomer Design
– Modifying reaction kinetics with crown ethers
– Crown ether size effect is observed
• Epoxy Blends
• NMR Complex Determination
Matthew J. Spencer, James V. Crivello, Chang Y. Ryu