利用高碘酸钠选择性氧化阔叶木浆

Selective Oxidation of Hardwood Pulp by Sodium Periodate

关键词:  高碘酸钠  选择性氧化  醛基含量  聚合度

Key Words:sodium periodate  selective oxidation  aldehyde group  degree of polymerization

摘要:高碘酸钠(NaIO4)选择性氧化纤维素得到双醛基纤维,提供了活性反应部位,可引入其他带电基团,增加纤维的润胀能力和分散特性,有利于制备微纤化纤维素(MFC)时机械处理过程中纤维的分丝帚化。采用正交实验分析了反应时间、反应温度、氧化剂用量和浆浓对NaIO4选择性氧化阔叶木浆的影响,通过测定醛基含量和聚合度分析主要影响因素,优化反应条件,同时探讨了打浆预处理以及体系的pH值对氧化反应的影响。结果表明,浆料的醛基含量随着氧化过程温度的升高、时间的延长、氧化剂用量和浆浓的增加而增加,聚合度则呈现下降的趋势。NaIO4用量对氧化阔叶木浆纤维的醛基含量和聚合度的影响最为显著,浆料的打浆预处理对NaIO4的氧化反应影响不明显,反应体系pH值的影响较为明显。NaIO4氧化阔叶木浆的优化条件为：反应温度45℃,反应时间2～3 h,NaIO4用量50%,浆浓2%～3%,pH值5～6。

Abstract:In the selective oxidation reaction between sodium periodate and hardwoodpulp,factors influencing the content of aldehyde group and degree of polymerization (DP) were investigated by using orthogonal experimental method in order to find out the main factor among reaction time,temperature,oxidant dosage and stock consistency. The influence of pH value and freeness of the pulp on oxidation reaction was also studied. The results showed that the content of aldehyde group increased with reaction time,temperature,oxidant dosage and stock consistency increase,while the DP had a decrease trend. The higher of the aldehyde groupcontent,the lower of DP. The content of aldehyde group and DP were strongly related to oxidant dosage. Higher beating degree had no significant effect on oxidation reaction,while pH value showed remarkable influence. Synthetically considering both aldehyde group content and DP,the optimal condition for periodate oxidized reaction was as follows: 45℃,2～3 h,oxidant dosage 50%, stock consistency 2%～3%,and pH value 5～6.