【作者】 谭本祝；

【导师】 钱宇； 詹怀宇；

【作者基本信息】 华南理工大学 ， 化学工程， 2002， 博士

【摘要】 办公废纸已成为四大废纸之一,它的纤维长,品质好,价格低廉,是最好的潜在再生纤维资源。混合办公废纸回收的主要问题是静电复印纸和激光打印纸等非接触式印刷废纸所占比例较高。非接触式印刷油墨的组成和性质与传统油墨有较大的差别,常规脱墨方法难以脱除。废纸脱墨是一个复杂的化学和物理过程,需要机械、热和化学品的协同作用。表面活性剂在脱墨中起着相当重要的作用,主要具有去污、分散、乳化、捕集和发泡等功能。因此,研究混合办公废纸的脱墨化学和表面活性剂结构对脱墨的影响,对提高混合办公废纸的利用率具有重要的意义。本论文根据阴离子聚合原理以含活泼氢物质为起始剂,在碱催化下进行了环氧乙烷、环氧丙烷的开环聚合,得到PEP 型非离子表面活性剂、脂肪醇聚氧乙烯聚氧丙烯嵌段共聚醚。通过引入环氧丙烷单元对现有的AEO 和TX 系列表面活性剂进行了改性。通过羧甲基化反应得到了烷基醚羧酸表面活性剂。采用红外光谱和H-NMR 谱分析对它们的结构进行表征。研究了表面活性剂的表面物化性能、应用物性与结构的关系。对于PEP 型非离子表面活性剂,降低表面张力的能力不仅与PO/EO 有关,而且与各链段的长度有关。EO 链段长相同,PO/EO 越大,表面张力越低;PO/EO 相同,EO 链段越长,表面张力越低。对相同的起始剂,浊点随PO 数的增加而降低。对于脂肪醇聚氧乙烯聚氧丙烯嵌段共聚醚,烃基碳原子数越多,表面张力越大。随着分子中PO加合数的增加,表面张力增加,水溶性降低,起泡力减弱,泡沫稳定性变差。对于烷基酚聚氧乙烯聚氧丙烯醚,随着PO 单元数的增加,降低表面张力的能力下降,亲水性变差,起泡力和泡沫稳定性降低。以浮选脱墨浆的ERIC 值和浮选脱墨率为评价指标,研究了表面活性剂结构对浮选脱墨效果的影响规律。脂肪醇聚氧乙烯聚氧丙烯共聚醚和烷基醚羧酸类表面活性剂的浮选脱墨效果较好,脱墨浆中有效残留油墨浓度较低,脱墨率较高。对于PEP 型表面活性剂,分子结构中存在一最佳的PO 加合数,起始剂不同,最佳PO 加合数不同。十二烷醇聚氧乙烯醚(AEO)和烷基酚聚氧乙烯醚(TX)系列更多还原

【Abstract】 Office wastepaper has been becoming one of the large four classes of wastepapers for ever-increasing utilization of xerographic and laser printed paper.Recycled office waste papers are potentially an excellent source of low cost, highquality fiber for the papermaking industry. The major problem in using mixed officewastepaper (MOW) is that it contains a high percentage of difficut-to-deink,non-impact printed papers, such as photocopier and laser printed papers. The inks fornon-impact printing are very different from the traditional in their compositions andcharacters. This type of ink particle is very difficult to remove from the pulp byconventional mechanical means such as washing, flotation, screening and centrifugalcleaning. Deinking of secondary fiber is a complicated chemical and physical process.Ink removal requires chemical, mechanical, and thermal energy. Each of these energyinputs interacts with the others. Surfactants play important roles in deinkingoperation, its main functions are decontamination, dispersion, wetting, emulsification,collection, foaming. Therefore, for increasing utilization rate of MOW, it is veryimportant to study deinking chemistry of MOW and the effect of surfactant structureon MOW deinking.Based on the principle of anion polymerization, a series of surfactants areprepared in this dissertation. PEP surfactants are prepared by reaction of propyleneoxide with compounds containing two reactive hydrogen atoms in the presence ofpotassium hydroxide. Using an alcohol with 8 to 18 carbon atoms per molecule as aninitiator, the alcohol is condensed with ethylene oxide, followed by propylene oxide,in the presence of potassium hydroxide and a proper temperature, to give a range ofmonoalkyl ethers of ethylene oxide/propylene oxide block copolymers. Adding POunits modifies a series of AEO and TX surfactants. Carboxymethylated alcohol ethersare prepared by the reaction of ether alcohols and chloroacetic acid with sodiumhydroxide. The molecule structures of surfactants prepared are confirmed by IRspectrum and H-NMR spectrum analyses. 1The relations of basic surface physicochemical properties and appliedperformance of surfactants with its structure are investigated. The surface tension ofPEP nonionic surfactants depends on not only PO/EO but also the respective chainlength of PO and EO. For the same in the chain length of EO, the surface tensiondecreases with the increase of PO/EO value. For the same in PO/EO value, thesurface tension decreases with the increase of the chain length of EO. For the sameinitiator,the cloud point lowers with the increase of PO content. For fatty alcoholsethylene oxide/propylene oxide block copolymer, the surface tension increases as thecarbon-chain length in the alkyl increases. As the number of PO units in moleculestructure increases, the surface tension increases while water-solubility, foaming andfoam stability decreases. The similar variation can be found in alkyl phenols EO/POblock copolymer. The more the number of PO units, the higher the surface tensionand the poor the water-solubility, foaming and foam stability. Using ERIC value of flotation accepts and flotation-deinking efficiency as theevaluation indexes of a flotation deinking process, the effects of surfactant structureon flotation deinking of MOW are studied. Both high-alcohol EO/PO blockcopolymers and alkyl ether carboxylic acids surfactants have better flotation deinkingeffects than the others in the research. The ERIC values of their flotation accept arelower and the flotation deinking efficiencies are higher. For PEP surfactants, there isan optimal value for the number of PO unit in molecule, which varied with theinitiators. As compared with AEO and TX series, modified surfactants by adding POunits can improve the effects of MOW flotation deinking. For the same number of EOunits, the flotation accepts ERIC response decreases as the number of PO unitsincreases. Generally speaking, for the same number of PO units, the flotation acceptsERIC response decreases as the number of EO units increases. Studies on agglomeration deinking of MOW are performed. It is found thatsurfactants can improve the effect of 1-Octadecanol agglomeration deinking and theinfluences of different surfactants have variations. For PEP surfactants, the deinkingeffect relates to not only PO/EO but also the respective chain length. As comparedwith AEO series, modified surfactants by adding PO units have poor deinking effects.更多还原