The influence of hot water pre-extraction of wheat straw hemicelluloses on monoethanolamine-AQ and soda-AQ pulp properties

In this research, hot water pre-extraction of wheat straw followed with monoethanolamine-Anthraquinone and soda-Anthraquinone pulping was investigated. The pre-extraction satge of hemicelluloses with process variables of the temperature of 150 ◦C and the time of 45 minutes with water/straw ratio of 4/1 was selected as the optimum treatment. Among the pulps produced from unextracted wheat straw and pre-extracted wheat straw, monoethanolamine-AQ pulps have the highest yield. The highest drop in yield is observed in the case of soda–AQ pulp produced from pre-extracted wheat straw. In the same process conditions, the kappa numbers of monoethanolamine-AQ and soda-AQ pulps from unextracted wheat straw show the lower amounts than the pulps from pre-extracted wheat starw and the lowest kappa number belongs to monoethanolamine-AQ pulp made from unextracted wheat straw. Tensile indices of the pulps produced with pre-extracted wheat straw were decresedsignificantly. Burst index of soda-AQ pulp from pre-extracted straw was slightly improved a little decrease in the burst index of monoethanolamine-AQ pulp from pre-extracted straw occurs.The tear index of monoethanolamine-AQ pulp is significantly increased after the pre-extraction of the straw. The brightness of pulp from both processes is slightly decreased after pre-extraction. The opacity of soda-AQ and monoethanolamine-AQ pulps from pre-extracted straw was increased and decresed respectively.