【作者】 曹晶晶；

【导师】 杨益琴；

【作者基本信息】 南京林业大学 ， 制浆造纸工程， 2010， 硕士

【摘要】 本文以玉米淀粉为原料,以TEMPO（2,2,6,6-四甲基-1-哌啶氧基）和NaBr为催化剂、NaClO为氧化剂对玉米淀粉进行氧化改性。同时对氧化淀粉用于葡萄糖醛酸内酯的制备和纸页表面施胶方面的应用进行了探讨研究,主要研究结论包括以下几个方面。1、考查氧化剂用量、pH值、温度、反应时间对玉米淀粉氧化反应的影响。结果表明,pH值对氧化淀粉羧基含量的影响最大,其次为反应时间、氧化剂用量、反应温度。各因素对氧化淀粉得率也有一定影响。玉米淀粉最佳氧化条件为:氧化剂用量35%（基于干淀粉）,pH值10.5,反应时间2.5h,温度0℃,此时,氧化淀粉的羧基含量最高,为5.30%,得率为88.83%。2、红外光谱图表明,与原淀粉相比较,氧化淀粉在1620 cm^-1附近有一明显的羧基特征吸收峰,说明在氧化淀粉中有羧基生成。扫描电镜分析表明,随着氧化程度的加深,氧化淀粉颗粒表面破损情况加剧,氧化反应不仅在淀粉表面进行,颗粒内部也有发生。3、考察酸种类、酸浓度及水解时间对氧化淀粉水解反应的影响。实验结果表明HCl的催化效率略优于H₂SO₄,当HCl浓度为0.1mol/L反应时间为2h时,水解液中葡萄糖醛酸含量达到最大。4、水解液浓缩后在冰醋酸条件下进行内酯化,考察反应温度、冰醋酸用量对葡萄糖醛酸内酯收率的影响,得到最佳内酯化条件为温度65℃,冰醋酸用量0.5mL/g原淀粉,此时内酯收率为17.73%。样品经检测纯度达93.03%,熔点为176¹79℃,25℃时比旋光度为+20.25°（H2O溶液）。5、用不同羧基含量的氧化淀粉对纸张进行表面施胶实验,考察淀粉氧化程度对纸张施胶前后性能的影响。结果表明,羧基含量为0.30%的氧化淀粉对瓦楞原纸的施胶效果最佳,羧基含量为0.75%的氧化淀粉对文化用纸的表面施胶效果最佳。更多还原

【Abstract】 With TEMPO/NaBr as catalyst, corn starch was oxidized by NaClO. The preparation of glucuronolactone by oxidized starch and the application of oxidized starch at surface sizing were studied. The main work and conclusions are as follows.1) Effect of amount of NaClO, pH, reaction temperature, reaction time on the amount of carboxyl content of the product and yield of oxidized starch were researched. As the results showed, the most important factor was pH, and then were reaction time, oxidant amount and reaction temperature. The optimum reaction conditions were as follows, reaction time 2.5 hours, pH 10.5, temperature 0℃, the amount of NaClO 35% of starch while carboxyl content of oxidized starch reached the highest 5.30% and yield was 88.83%.2) Structure of oxidized starch was characterized by Scanning Electron Microscopy （SEM）. Result showed that there was carboxyl group in oxidized starch. From the result of Infrared Spectroscopy （IR） analytic we can find that starch surface damage became severer when oxidation degree increased. Oxidation took place not only on the surface of starch, but also inside the particle.3) Effects of kinds of acid, acid concentration, reaction time on the hydrolysis of oxidized starch were studied. The results showed that the catalytic efficiency of HCl was slightly higher than that of H₂SO₄ in the same conditions. When concentration of HCl was 0.1 mol/L and reaction time was 2 hours, concentration of glucuronic acid in hydrolysate reached the highest .4) Lactonization of hydrolysate occurred in acetic acid after dewater treatment. Effects of temperature, amount of acetic acid on yield of glucuronolactone were investigated. The best conditions of lactonization were as follows, reaction temperature 65℃, amount of acetic acid 0.5mL/g corn starch while yield of glucuronolactone was 17.73%. The purity of the sample was 93.03%, melting point was 176¹79℃, specific rotation at 25℃was +20.25°（H2Osolution）.5) Oxidized starch with different carboxyl content were used as surface sizing agent. Relationship between starch oxidation degree and surface sizing effect was studied. Experiment showed that, sizing effect of corrugated medium was the best while carboxyl content of oxidized starch was 0.30%.The best sizing effect of cultural paper was achieved when carboxyl content was 0.75%.更多还原