ISOLATION AND UTILIZATION OF MODIFIED HEMICELLULOSE FROM SPENT PULPING LIQUOR

Hemicellulose is one of two major organic components in pulping spent liquor. Its recovery and comprehensive utilization have long presented an urgent problem to be solved. To separate hemicellulose from spent liquor for study, lignosulfonate must be removed first before Modified Hemicellulose (MH) can be extracted from the magnesium bisulfite pulping effluent of reed. By means of gas chromatography and infrared spectrometer MH thus extracted is found to be mainly composed of arabinose and xylose with some amount of glucose and a little of galactose and mannose. Studies are also conducted of MH as a surface sizing agent for corrugating medium manufactured from recycled fiber. The results show that MH as a surface sizing agent can effectively increase breaking length, bursting strength, ring crush compression resistance and folding endurance, but slightly decrease the brightness of the paper. When the concentration of the sizing solutions is kept at 9 similar to 11% and just the right amount of borax is added to the solutions, maximum increase of paper strength can be obtained. Under the above condition, the properties of MH treated paper can be compared with or in some cases superior to those of oxidized starch treated paper used as a control.