TABLE 2.
Purity of PHO according to the solvent used for precipitation
| Solvent used for precipitation | % Purity (wt/wt)a |
|---|---|
| Absolute methanol | 91 ± 0.4 |
| Methanol (90%, vol/vol) | 86 ± 1.1 |
| Methanol (70%, vol/vol) | 96 ± 0.7 |
| Absolute ethanol | 98 ± 0.6 |
| Ethanol (70%, vol/vol) | 97 ± 0.5 |
| Ethanol-methanol (70%, vol/vol) mix | 99 ± 0.2 |
| Water | 91 ± 0.7 |
| Standardb | 84 ± 1.5 |
a
The purity of the obtained PHO samples was determined by GC analysis of dried polymer material. Analyses were done in triplicate, and mean values and standard deviations are shown.
b
Standard PHO available at our laboratory was prepared by at least three repeated cycles of dissolution in chloroform and precipitation with ethanol; afterwards the polymer was dried to a constant weight and analyzed by GC.