ROLE OF ANTHRAQUINONE DURING COLD AND HOT REFINING OF BLEACHED BAGASSE PULP

Hot refining of bleached bagasse pulp using 5% sodium hydroxide solution resulted in a less accessiblefine structure, higher crystallinity and lower reactivity in xanthogenation than cold refining using 15%sodium hydroxide solution. cold refining using sodium hydroxide–anthraquinone liquors raised the yield,a-cellulose and lowered the hemicelluloses, improved greatly the affinities towards water and alkali,resulted much better reactivity in xanthogenation and improved the filterability. hot refining using sodiumhydroxide–anthraquinuone liquors led to lower a-cellulose, lower degree of polymerization (d. p.), lowerfilterability but it led to higher yield, higher crystallinity more open and accessible fine structure, higherhemicelluloses and much better reactivity in xanthogenation. the results show that the penetration of the bulky molecule within the cellulose chains increased its accessibility towards alkali. this increased itssensitivity towards degradation which indicated by the decrease in a-cellulose being 98.4% cold refiningand 93.5% hot refining. this reftected on the d. p. the shorter of the chains led to higher reactivity inxanthogenation which over come the increase in crystallinity.