Lignin is an aromatic network polymer composed of phenylpropanoid units. It is helpful for binding cellulose and hemicelluloses together in lignocelluloses. Its content in lignocelluloses normally ranges from 18% to 35% [24]. The hydrophobicity of lignin is higher than that of cellulose and hemicelluloses, and its properties depend on the applied extraction methods. Although lignin is usually regarded as a waste material, many studies on the application of lignin have been conducted in recent years [25]. Sakagami et al