2.1. Materials
A commercial bleached flax fabric was used. Chestnut pericarp
(outer shell) was provided by a fruit-processing plant in Tianjin
City, China. Three different mordants were used, namely, aluminum
potassium sulfate (KAl(SO4)212H2O), ferrous sulfate (FeSO4
7H2O), and stannous chloride (SnCl25H2O). Nonionic surfactant,
which used sodium chloride as accelerating agent in the
dyeing process, was supplied by Nafine Chemical Industry Group
Co., Ltd. (China). All chemicals and reagents were of laboratory
reagent grade and were commercially available.