【作者】 陶正毅；

【导师】 武书彬；

【作者基本信息】 华南理工大学 ， 制浆造纸工程， 2012， 博士

【摘要】 为缓解目前因木薯渣综合利用水平不高带来的资源浪费及环境污染等问题，本研究旨在将其作为合成造纸化学品的原料，在丰富其综合利用方式、实现高附加值转化的同时，开发出新型造纸湿部化学助剂以补充现代造纸行业发展的需求。木薯渣富含粗纤维及淀粉，本文通过对木薯干渣进行适当物理和化学预处理使其适用于特定的化学改性，同时通过对合成工艺的优化制备具有助留助滤性能的造纸化学品，并将其应用于纸浆中评价其使用效果。SEM分析发现，木薯渣是由大小不等、密度不均的淀粉颗粒及粗纤维构成的非匀质混合物，其中纤维以粗长纤维束、纤维碎片及块状纤维组织三种形式存在，块状纤维组织又与淀粉相互包裹。通过纤维粉碎机粗磨及球磨微粉化处理后，纤维尺寸接近甚至小于淀粉颗粒，原料得到充分匀质化处理后，通过酸水解结合IC分析得到木薯渣中葡萄糖含量为81.21%、木糖3.66%、半乳糖1.91%、阿拉伯糖1.41%，证实其具有较高的再利用价值。在球磨预处理基础上，通过探头式超声波深度处理，精制原料相对结晶度由36.25%下降至30.08%，保水值进一步提高至414.5%。此时木薯渣精制原料PCD（Pretreated Cassava Dregs）的对改性反应的均匀性及试剂可及性明显得到改善，可用于功能衍生化改性。通过溶媒法使PCD在有机溶剂中分别与3-氯-2羟丙基三甲基氯化铵（CHTAC）及一氯乙酸反应合成阳离子改性产物CPCD及阴离子改性产物CMPCD，其中阳离子醚化反应优化工艺为：反应体系介质为70～80%异丙醇或乙醇（体积浓度），PCD浓度为10%，超声波辅助碱化过程功率为81W，处理时间为10min，m_NaOH: m_CHTAC=0.3：1，m_CHTAC:m_PCD较合理的范围为0.5～0.7:1，反应温度为55℃，反应时间为3.5h；阴离子醚化改性优化条件为：80%乙醇浓度，PCD浓度15%，改性试剂物质的量比值N_NaOH：N_氯乙酸=2.2:1；N_氯乙酸：N_PCD=0.91:1；反应温度55℃，时间4.5h；在PCD醚化改性产物的基础上，通过KMnO₄/H⁺引发体系合成了CPCD与丙烯酰胺的阳离子接枝聚合物CPCD-g-PAM及CMPCD与丙烯酰胺、甲基丙烯酰氧乙基三甲基氯化铵的两性二元单体接枝聚合物CMPCD-g-AD，并对影响接枝共聚反应的因素如引发剂浓度、单体比例及浓度、pH值、预氧化时间、反应温度、反应时间、醚化产物取代度、底物浓度等进行了较为详细的讨论，总结归纳了这些因素对接枝聚合反应及产物性质的作用规律。通过SEM、FT-IR、¹³C-NMR及TG等方法对木薯渣系列改性产物的化学结构及热稳定性质进行了表征，它们均证实了相应合成反应的发生。在水相中合成了阳离子醚化剂CHTAC，并成功将顶空气相色谱HS-GC技术应用在其合成过程中主要有机挥发性物质的测定，该方法利用称量式取样及大比例稀释的方法快速制备分析样品，同时还具有较高的精准度（相对标准偏差RSD<2.5%，样品回收率Recovery=101～105%）。此外，还通过化学衡算推导出基于GC信号与取样质量的主产物转化率公式。在此基础上，利用顶空气相色谱技术确定了水相中合成CHTAC的优化工艺条件为：反应物浓度2mol/kg（以三甲胺盐酸盐TMAC计）；物料比为N_ECH：N_TMAC=1.1：1；初始pH值为7；催化剂为ZnO，用量2%；反应过程采取三段式升温，分别为：12～14℃反应3.5h；由14℃升温至40℃共反应40min；40℃反应至6.5h。在此条件下主产物产率可提高至95%，粗产物中有效物CHTAC理论含量为25.79%，DCP含量约为0.23%（2279.7mg/kg）, ECH含量为0.04%（393.8mg/kg）。依次经过旋转蒸发、氯仿萃取及水蒸气抽提等精制工艺，粗产物中ECH及DCP含量分别降低至1.5mg/kg及25mg/kg，将其用于PCD的阳离子化改性取得了较好的应用效果。木薯渣系列改性产物对100%废纸浆具有较好的助留助滤性能，其中CMPCD-g-AD与CPCD助留助滤性能较为优异。单独添加0.4%的CMPCD-g-AD时，纸浆细小组分单程留着率FPR可由未添加时的78.69%提高至93.3%；CPCD在0.1%的用量时，FPR可提高至89.35%。若预先用0.6%PAC预先添加至废纸浆中，后仅加入0.14%的两性助剂CMPCD-g-AD，FPR可在PAC添加效果达到饱和的情况下（88.37%）大幅度提高至93.71%；0.1%的CPCD用量可在PAC添加后将FPR提高至92.56%，但继续添加会出现体系过阳离子化，FPR明显下降。木薯渣改性助剂在6.5～8.5的pH范围内，其助留助滤性能无较大变化，表现出季铵盐阳离子基团较好的pH适应性，同时两性助剂还表现出较好的抗剪切能力。手抄纸实验发现，添加少量CMPCD-g-AD可大幅增加纸张定量，用量为0.2%时，手抄纸定量较空白样（已添加0.5%PAC）增加10.36%，经换算，纸浆细小组分单程留着率由69.58%提高至90.09%；当用量为1.2%，其定量增加14.06%，FPR提高至97.41%，此时成纸的抗张指数、耐破指数及撕裂指数分别增加17.47%、25.56%、6.83%；高取代度CPCD按0.5%添加，可获得一定的增干强效果，但会造成体系过阳离子化，助留助滤效果下降明显。更多还原

【Abstract】 In order to alleviate the resources waste and pollution caused by a lack of way forcassava dregs（CD） comprehensive utilization, this study aims to use CD to synthesis newpaper wet end chemical agents to meet the demends of modern paper industry and to realizehigh added value transformation. CD is rich in crude fibre and starch, once pretreated byappropritate ways, the starch and cellulose in it could be well used for chemical modificationand applied as retention&filter aids.With SEM analysis, CD was mainly comprised of cellulose and starch with different sizeand density, and the cellulose existed in long crude fibre bundle、fiber fragments and reticularfibre, especially the starch was packaged by reticular fibre. With fiber coarse grinding andball-mill micronization pretreatment, fiber size was close to or even less than starch and theCD can realize homogenization. With sulfuric acid hydrolysis of CD and ion chromatographanalysis, four kinds of monosaccharides were detected and respectively with content of81.21%glucose,3.66%xylose,1.91%galactose,1.41%arabinose. After homogenization, therelative crystallinity of CD decreased to36.25%. On the based of homogenization, ultrasonicfurther pretreatment could promote relative crystallinity decrease to30.18%and improveWRV increase to414.5%. After series of pretreatment described as above, the pretreatedcassava dregs （PCD） could be used for chemical modification with good reaction uniformityand nice accessibility for chemical reagent.Cationic and anionic etherificatin modified product of PCD were synthesizedrespectively by reacting with3-chloro-2-hydroxypropyltrimethylammonium chloride（CHTAC） and chloroacetic acid. The optimization parameters of cationic etherificationmodified was describe as follow: concentration of isopropyl alcohol or ethanol （V/V） was70⁸0%, PCD10%, m_NaOH: m_CHTAC=0.3：1, m_CHTAC: m_PCD=0.5⁰.7:1, alkalization assistedwith ultrasonic-10min/power81w, reaction temperature55℃, reaction time is3.5h;Anionic etherification modified optimal conditions:80%ethanol, PCD15%, N_NaOH: N_chloroactic acid)=2.2：1; N_{chloroactic acid}: N_PCD=0.91：1; reaction temperature55℃, reactiontime4.5h. Meanwhile, the CPCD and CMPCD were used as substrate for graftting copolymerization with monomer of acrylamide and acrylamide&[2-（methacryloyloxy）ethyl]trimethylammonium chloride respectively, and CPCD-g-PAM、 CMPCD-g-AD weresynthesised accordingly. The influence factors of the grafting copolymerization reaction, suchas the initiator concentration, monomers ratio and concentration, pH value, preoxidation time,reaction temperature, reaction time, substitution degree of etherification product, substrateconcentration were discussed in detail, and summarized the effect of these factors onmolecular weight and charge density of product. Then SEM, FT-IR,¹³C-NMR and TGanalysis technical were used for study on chemical structure and thermal stability propertiescharacterization of PCD modified products, and all of them had proved the correspondingproduct were synthesised successfully.A headspace gas chromatographic（HS-GC） technique for the determination of residualEpichlorohydrin （ECH） and generated1,3-Dichloro-2-Propanol （DCP） in synthesis processof CHTAC was set up. By a weight-based sampling method, coupled with significant dilutionin15.8%sodium sulfate and0.1%silver nitrate mixed solution rapidly, the sample forHS-GC analysis was prepared. Based on the reaction stoichiometry, the conversion ofCHTAC during the synthesis process could be calculated from sampling weight and GC peakarea. The results showed that the method has a good measurement precision （RSD <2.5%）and accuracy （Recovery=101～104%） for the quantification of both ECH and DCP inthe process samples. It was simple and accurate and used for the efficient determination of theCHTAC conversion in the synthesis research. With assistance of this method, the optimalsynthesis condition of CHTAC in aqueous phase was obtained—TMAC:2mol/kg; N_ECH: N_TMAC=1.1：1; initial pH value7; catalyst:2%ZnO; the process of reaction:12¹4℃,3.5hfollowed heating up to40℃,40min and then40℃,6.5h. On this condition, the conversionand concentration of CHTAC was95%,25.79%respectively, DCP0.23%, ECH0.04%. By aprocess of purification such as rotating evaporation, chloroform extraction and water vaporextraction, the purified product had good application.Series derivatives of PCD had good retention and filter aid performance on recycleddeinking pulp.0.4%addition of CMPCD-g-AD could increase first pass retention （FPR） offine components from78.69%to93.3%, and0.1%CPCD could increase the FPR to89.53%.With pre-addition of0.6%PAC,0.14%CMPCD-g-AD could increase FPR from88.37%to 93.71%, and0.1%CPCD could increase FPR to92.56%. But more addition of CPCD wouldcause retention and filter property decrease. The fuction of PCD derivatives hardly change aspH value varied from6.5⁸.5and showed good adaptability of quaternary ammonium saltcationic groups to pH. Meanwhile, CMPCD-g-AD showed good shearing resistance ability.Handsheet experiment showed that CMPCD-g-AD dramatically increase the paperquantitative. With0.2%addition of CMPCD-g-AD, the quantitative （compared with0.5%PAC） increased by10.36%, the FPR increased from69.58%to90.09%, meanwhile thephysical strength had little increase; When amount to1.2%, the quantitative increase14.06%,FPR increased to97.41%, the tensile index, brust index and tear index of handsheetrespectively increased by17.47%,25.56%and6.83%. With0.5%addition of CPCD （highDS）, Even the physical strength have large increased, the performance of retention reduced.更多还原