Table 4.
Polymerization of rac‐lactide in bulk using [Zn(DMEGhydroqu)2](OTf)2 (C3).[a]
|
Entry |
[M]/[I] |
k app [b] [s−1] |
t [s] |
Conv.[c] [%] |
M n,theo. [d] [g mol−1] |
M n [e] [g mol−1] |
Ð [e] |
|---|---|---|---|---|---|---|---|
|
1 |
1000 : 1 |
0.0379 |
166 |
80 |
115000 |
45500 |
1.4 |
|
2 |
1250 : 1 |
0.0245 |
225 |
79 |
142000 |
77000 |
1.5 |
|
3 |
1500 : 1 |
0.0126 |
285 |
64 |
138000 |
94400 |
1.5 |
|
4 |
2000 : 1 |
0.0061 |
405 |
53 |
153000 |
82100 |
1.4 |
|
5 |
2500 : 1 |
0.0017 |
582 |
48 |
173000 |
74200 |
1.4 |
|
6[f] |
2500 : 1 |
0.0069 |
285 |
49 |
177000 |
146000 |
1.4 |
[a] Conditions: non‐purified technical grade rac‐lactide, solvent‐free conditions, 150 °C, stirrer speed: 260 rpm. [b] The rate constant k app was determined by plotting ln([LA]0/[LA]t) vs. t. [c] Determined by 1H NMR spectroscopy. [d] Theoretical number‐average molar mass calculated by conversion×molar mass×[M]/[I]. [e] Determined via GPC analysis in THF. Mn : determined number‐average molar mass [f] Sublimated lactide. Ð: polydispersity obtained by Mw /Mn .