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13
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

Transcript of APS Dallas

Supramolecular Arrest and Activation

for the Network formation of Acid

Catalyzed Epoxy Polymerization

Matthew J. Spencer, James V. Crivello, Chang Y. RyuDepartment of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute

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

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-

hAr2I+ MtXn

-* ArI+ MtXn

- + Ar

Ar+ MtXn- + ArI

. .HMtXn

k1

10

30

50

70

90

110

130

150

170

190

0 20 40 60 80 100 120 140 160

Tem

pera

ture

(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

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)

Tem

per

atu

re (

oC

)

OO

O

OO

2700 mJ/cm2

I+ O n-C11H23

SbF6-

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

Neopentlyglycoldiclycidyl ether Trimethylolpropane

triglycidyl ether

Methyl glycidylether

Dynamic Shear Rheology

Matthew J. Spencer, James V. Crivello, Chang Y. Ryu

G* = G’ + iG’’

δ = atan(G’’/G’)

Dynamic and Steady Shear Experiments

Dynamic

Steady

Model CompoundDipropylene Glycol Dyglicidal Ether

Matthew J. Spencer, James V. Crivello, Chang Y. Ryu

Modifying Reaction Kinetics with Crown Ethers

18-crown-6

1050 mJ/cm2

Matthew J. Spencer, James V. Crivello, Chang Y. Ryu

10

30

50

70

90

110

130

150

170

190

0 20 40 60 80 100 120 140 160

Tem

pera

ture

(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

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

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

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