Table 1.
The parameters of the ring-opening polymerization (ROP) of d,l-lactide (LA), l,l-lactide (LLA), and ε-caprolactone (CL) initiated by β-CD.
| Entry | [I]/[M] | Temperature (°C) |
DP a | DS b |
Mn(NMR)c (Da) |
Mn(SEC-MALLS)d (Da) |
ĐM d | Yield (%) |
|---|---|---|---|---|---|---|---|---|
| β-CD/PCL50 | 1/50 | 140 | 5.6 | 3.3 | 3200 | 3800 | 1.23 | 85 |
| β-CD/PLLA50 | 1/50 | 140 | 8.1 | 11.3 | 7700 | 8800 | 1.35 | 73 |
| β-CD/PCL100 | 1/100 | 140 | 11.2 | 13.0 | 17600 | 18700 | 1.26 | 91 |
| β-CD/PLA100 | 1/100 | 140 | 5.6 | 19.6 | 9000 | 10100 | 1.25 | 69 |
| β-CD/PLLA100 | 1/100 | 140 | 6.4 | 19.3 | 10000 | 10800 | 1.41 | 73 |
| β-CD/PCL100 | 1/100 | 100 | 6.9 | 8.0 | 7400 | 7300 | 1.23 | 47 |
| β-CD/PLA100 | 1/100 | 100 | 2.9 | 8.7 | 4800 | 5200 | 1.47 | 34 |
| β-CD/PLLA100 | 1/100 | 100 | 3.3 | 8.3 | 5100 | 6300 | 1.36 | 51 |
Reaction conditions: argon atmosphere, I = initiator - β-cyclodextrin (β-CD); M = monomers; ε-caprolactone (CL), l,l-lactide (LLA), d,l-lactide (LA), reaction time: 48 h. a DP—the average degree of polymerization determined by 1H NMR analysis, calculated based on the area ratio of the terminal methine proton of PLA or PLLA (4.21 ppm) or terminal methylene protons of PCL (3.36 ppm) to the internal methine proton of PLA or PLLA (5.19 ppm) or methylene proton of PCL (3.98 ppm). b DS—the average degree of substitution determined by 1H NMR analysis; calculated based on the area ratio of the terminal methine proton of PLA or PLLA (4.21 ppm) or terminal methylene protons of PCL (3.36 ppm) to the H-1 protons of β-CD (7H, 4.83 ppm). c Mn(NMR) determined by 1H NMR spectroscopy. d Mn(SEC-MALLS) and molar-mass dispersity ĐM determined using SEC-MALLS method.