【作者】 张锐；

【导师】 王双飞； 郭勇为；

【作者基本信息】 广西大学 ， 制浆造纸工程， 2008， 硕士

【摘要】 高得率竹浆中含有大量木素使其容易返黄,很大程度上限制了其使用范围和经济效益,目前已有较多关于助剂用于抑制高得率纸浆光诱导返黄的研究。本文通过反应使自由基捕获剂4-氨基-2,2,6,6-四甲基哌啶(TAD)阳离子化,提高其与浆料中纤维的结合力。通过实验对其合成工艺进行了优化,并对最终产物作了结构分析。通过在APMP竹浆中浆内施胶和表面喷淋实验,比较了产物、原料TAD及外购的紫外线吸收剂UVA的抑制返黄效果,并分析了产物应用的工艺条件。最后通过扫描电镜和红外光谱实验初步分析了产物在APMP竹浆中应用的返黄抑制机理。优化后的合成工艺为:第一步缩合反应:原料用量比(三聚氯氰摩尔量:TAD摩尔量)为1:1,pH值8～9,温度0℃,分散剂(乙醇)用量(乙醇质量:三聚氯氰质量)7:1,时间2h。第二步缩合反应:分散剂(水)用量为50ml(中间产物用量0.005mol时),原料用量比(阳离子剂摩尔量:中间产物A摩尔量)为2:1,pH值<7,温度30℃,时间1h。产物的紫外光谱和红外光谱分析表明,几种反应单体的主要吸收峰都在谱图中出现,说明反应按照设定方向进行,反应物主要结构进入了分子。在APMP竹浆中的应用表明,产物具有一定的返黄抑制能力,效果明显高于原料TAD,而略高于外购的UVA,且与UVA有一定的协同作用。当产物用量增加到0.7%时,其抑制返黄的效果趋于稳定。对纸样的扫描电镜分析表明,产物能很好的与纤维表面结合,而留着在纤维网状结构中。而红外光谱谱图分析表明,产物和UVA的加入对纸样光老化前后发色基团的含量有一定的影响,但作用方式有所不同。合成的新型返黄抑制剂有较强的纤维结合力,能更好的在高得率竹浆内使用,且抑制返黄效果明显强于原料TAD。更多还原

【Abstract】 In the high-yield bamboo pulps there is a lot of lignin which lets it be yellowed easily, and limits the scope of its use and economic benefits. There are a lot of studies on inhibiting light-induced yellowing of high-yield pulps with additives. A new fiber-reactive yellowing inhibitor was synthesized from radical scavenger, 4-amino-2,2,6,6-tetramethy piperidine (TAD). The synthetic process of fiber-reactive yellowing inhibitor was optimized, and the structure of final product was established by UV and FTIR. By sizing and surface spraying experiment in APMP bamboo pulps, the yellowing inhibition effect of final product, TAD and purchased UV-absorber was compared, and the application condition of final product was studied. The mechanism of final product inhibiting yellowing of APMP bamboo pulps was studied by SEM and FTIR.The optimized synthetic process conditions are listed as follow:The first step: the molar ratio of cyanuric chloride to TAD is 1:1; the pH of the reacting system is 8～9; the reaction temperature is 7℃; the reaction time is 2h; choose ethyl alcohol as the dissolvent, and the mass ratio of ethyl alcohol to cyanuric chloride is 7:1.The second step: choose deionized water as the dissolvent, and the dosage of deionized water is 50ml when the dosage of product in the first step is 0.005mol; the molar ratio of cationic reagent to the product in the first step is 2:1; the pH of the reacting system is lower than 7; the reaction temperature is 30℃; the reaction time is 1h. From the UV-Visible spectrum and FTIR-IR spectrum of the final product, major absorption peaks of the reactions can be found, which means the reaction carried out in the expecting way, and the main structure of reactions was in the final product.The application in APMP bamboo pulps indicated that the effect of the final product to inhibit yellowing is much better than TAD and a bit better than purchased UV-absorber, and the final product has synergy with UVA. The effect tends to be stable when the dosage of product is up to 0.7%.The SEM figure of paper sample indicates that the product is fiber-reactive and can stay in the fiber web structure. The FTIR indicated that the amount of chromophores groups in paper sample before and after light-inducing was effected by product and UVA in different ways.The novel yellowing inhibitor is fiber-reactive, can be used in high-yield bamboo pulps and inhibit its light-induced yellowing much better than TAD.更多还原