Research Article
Intramolecular Lactonization of Poly(α-hydroxyacrylic acid): Kinetics and Reaction Mechanism
Table 4
PCA parameters describing the dominating spectral characteristics in the 1H NMR domain of lactone formation of PHA in the range of pH 1 to 5.
| pH | Explained by PC1 | Explained by PC2 | Explained PC1 + PC2 | Chem.shift PC1 | Chem.shift PC2 | Time at max. PC1 | Time at max. PC2 | % | % | % | ppm | ppm | min | min |
| 1 | 88.5 | 8.1 | 96.6 | 2.767 | 2.442 | 1600 | 90 | 2 | 87.5 | 10.1 | 97.6 | 2.761 | 2.416 | 1720 | 90 | 3 | 82.6 | 12.4 | 95.0 | 2.742 | 2.580 | 1500 | 50 | 4 | 77.9 | 18.0 | 95.9 | 2.717 | 2.397 | 1600 | 60 | 4.5 | 79.4 | 17.5 | 96.9 | 2.636 | 2.335 | 1600 | 60 | 5 | 86.1 | 9.3 | 95.4 | 2.561 | 2.297 | 1600 | 90 |
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