Analysis of samples was carried out by extraction in methanol followed by drying and
weighing. Infrared spectra were then obtained both of the dried extracts and of the
pyrolysis condensates of the extracts. Thermogravimetric analysis (TGA) was also
carried out by heating in a nitrogen atmosphere to 550 °C, cooling to 300 °C and
heating in air to 850 °C. Samples were dissolved in distilled water and the pH of the
resulting solution measured.