Table 1.
aEffect of dissolved oxygen on Rp and tinh in polymerization initiated by eosin or I2959.
| Concentration | Rp | tinh | tinh no argon | ||
|---|---|---|---|---|---|
| Initiator | (M) | Argon | (M/s) | (s) | tinh with argon |
| Eosin | 4 × 10−6 | yes | 7.2 (+/− 1.1) × 10−3 | 5.6 (+/− 0.4) | 1.8 |
| + MDEA | no | 6.2 (+/− 0.6) × 10−3 | 10 (+/− 1) | ||
| Eosin | 4 × 10−7 | yes | 1.8 (+/− 0.2) × 10−3 | 31 (+/− 2) | 6.1 |
| + MDEA | no | 7.5 (+/− 0.5) × 10−4 | 190 (+/− 10) | ||
| I2959 | 4 × 10−3 | yes | 5.0 (+/− 0.3) × 10−2 | 9.0 (+/− 0.6) | 5.8 |
| no | 2.4 (+/− 0.2) × 10−2 | 52 (+/− 2) | |||
| I2959 | 4 × 10−4 | yes | 1.9 (+/− 0.2) × 10−2 | 10 (+/−3) | 8.7 |
| + MDEA | no | 1.3 (+/− 0.2) × 10−2 | 87 (+/−7) | ||
a
Polymerization rates were calculated for the region encompassing 5–30% conversion. Eosin-ITC-initiated reactions were performed with 420 mM PEGDA, 210 mM MDEA, and 35 mM VP in water exposed to 75 mW/cm2 light at wavelengths greater than 480 nm. I2959-initiated reactions were performed with the same monomer formulation, except 210 mM MDEA was only used as indicated. Irradiation conditions for I2959 initiation were 10 mW/cm2, 320–390 nm light. When indicated, monomer was bubbled with argon for 20 minutes immediately prior to polymerization.