Carboxymethyl cellulose from waste lignocellulosic pulps produced by a fast soda/AQ process

Cellulose pulps were prepared from ground branch wood from pine and poplar and ground wheat straw by a fast soda/anthraquinone pulping. This process u sed high pulping temperatures and short residence times. Various combinatio ns of temperature and time were used so that the H factor for pulps from pi ne and poplar was a constant 2700 while for pulps from wheat straw it was 2 70. The chemical composition of the resulting cellulose pulps was character ized and the possibility of synthesizing carboxymethyl cellulose from them was evaluated. The degree of substitution of our CMCs was found to be depen dent upon the source of the lignocellullosic material, but independent of t he pulping conditions for a specific substrate, (0.75 for pine, 0.82 for po plar and 0.89 for wheat straw). The rheological properties, the intrinsic v iscosity and the molecular weight of the CMCs were found to be dependent on the pulping conditions for each lignocellulosic tested. The molecular weig hts of our CMC samples were 219,000 to 316,000 for pine, 335,000 to 375,000 for poplar, and 350,000 to 383,000 for wheat straw. The molecular weights were highest for the pulps cooked at low temperatures.