Intramolecular Lactonization of Poly(α-hydroxyacrylic acid): Kinetics and Reaction Mechanism

Figure 3

¹³C NMR spectra of PHA (a) at pH 2 and (b) at pH 10.

(a) ¹³C NMR of PHA at pH 2

(b) ¹³C NMR of PHA at pH 10