Preparations and Characterizations of Carboxymetylated Hydrophilic Macromolecular Composites Directly Derived from Weeds

Abstract

  Direct carboxymethylations for aliphatic hydroxyl groups in weeds such as Tall fescue (Festuca arundinacea, TF), Sweeping lovegrass (Eragrostis curvula, SL) and Canada goldenrod (Solidago Canadensis, CG) were carried out in 2-propanol / 30 % NaOH at 55 °C for 3.5 hrs. Under the typical conditions, carboxyletylated TF (TF-CM), SL-CM and CG-CM were obtained at yields of 145%, 135% and 148% based on each dry weight of lignocellulosics, respectively. Although degrees of substitutions of these CM materials were only small values such as 0.08-0.11, almost all materials were easily dissolved into water. Structural features were investigated using FT-IR and UV-Vis. Visocosities of 1% (w/w) aqueous solutions or suspensions of CM derivatives were measured by vibrating viscometer under different temperatures and pH. Since there are differences on viscosities between TF and CG in spite of same degrees of substitution, properties were different due to different structures of plant tissues.