低温水热法降解桉木和绵竹硫酸盐木素的研究

从桉木、绵竹硫酸盐法制浆黑液中分别分离得到其硫酸盐木素,采用水热法对这2种木素在130、180、230℃的低温范围内分别作用15min和60min,分离其液、固相产物;并通过凝胶色谱(GPC)检测各油相及残留物的相对分子质量。结果表明,这2种木素的降解转化率均96%以;油1、油2是相对分子质量约300~400的小分子;而油3相对分子质量相对较大,约1200;当在230℃、60min条件下时,可能分子间发生了自身的二次缩合从而使残留物的相对分子质量急剧增加,甚至比降解之前更大。     

硫酸盐制浆过程中硫的分布与变化规律

本文研究了兴安落叶松硫酸盐制浆过程中流在蒸煮液、溶出木素和残余木素中的分布及变化情况。结果表明，蒸煮过程中蒸煮液的活性碱和硫化钠浓度不断下降，硫化度则不断上升，活性碱与硫化钠的消耗主要发生在初始脱水素阶段．溶出木素的含硫量在初始脱木素阶段量最高，随着蒸煮反应的进行，其百分含量逐渐下降，但绝对量却不断上升。蒸煮结束时，约占总用硫量1／5的硫与溶出木素结合在一起。木片或纸浆的含硫量与木素的硫化速率和残余木素的含量密切相关。在残余脱木素阶段，残余木素的硫化对木素的说除已没有促进作用。     

针叶木硫酸盐浆中残留木素的GIF体系仿酶降解机理的研究

由于针叶木硫酸盐浆中的残留木素含有大量难降解的LCC结构及其它缩合型木素结构,所以硫酸盐浆的分离木素可以用作难降解型木素大分子的一种结构模型。文章采用Cu2+/吡啶/过氧化氢组成的GIF仿酶体系对马尾松硫酸盐未漂浆的纤维素酶酶解木素(CEL)进行了仿酶降解,并对降解产物进行了分离和化学组成分析。通过FT-IR以及GC-MS测定,解析了CEL在降解过程中的结构变化,并对CEL的仿酶降解机理进行了探讨。研究结果表明:这种仿酶降解方法对浆中残留木素有较强的降解能力,一部分木素大分子被氧化降解为香草醛和香草酸等低分子化合物,使得降解后的产物中羰基和羟基增多。研究发现木素在仿酶体系中存在苯环及其侧链上C-H键的破坏、木素结构中Ca-Cb连接键的断裂、苯环的开环等反应。因此,该项研究可以为开发纸浆的仿酶漂白技术提供理论依据。     

裂解-气质联用分析氧漂过程中木素结构的变化

从针叶木硫酸盐原浆、氧漂浆以及氧漂后的废液中分离出残余木素,在四甲基氢氧化铵（TMAH）存在下,采用裂解气相色谱-质谱联用(Py-GC-MS)的方法研究了氧漂过程中木素分子结构的变化.对裂解产物的分析表明,木素裂解时产生多种甲基化的芳香化合物,以愈创木基型化合物为主;氧漂能够氧化和降解木素分子,产生更多的羧基化合物,氧化程度高的木素分子容易从纸浆中溶出,氧漂优先脱除沉积在纤维表面上的短侧链木素.     

脱氢二香草醇的合成及LCC的形成机理(Ⅰ)

合成了一种缩合型木素模型化合物——脱氢二香草醇,并利用红外光谱、核磁共振谱(1H-NMR)对其进行了分析和确认。在此基础上,模拟硫酸盐法蒸煮过程,将合成的木素模型物和典型的半纤维素组成部分(木聚糖)进行蒸煮,然后利用酸析沉淀木素、乙酸乙酯抽提的方法将蒸煮后的产物分级,并利用FT-IR、13C-NMR对分级后的各个部分进行分析,探讨传统硫酸盐法制浆过程中木素-碳水化合物复合体(LCC)的形成机理。研究发现脱氢二香草醇在硫酸盐法蒸煮过程中非常稳定,残留的脱氢二香草醇以及新形成的LCC主要存在于酸不溶物、乙酸乙酯抽提物中,大部分未降解的木聚糖存在于酸不溶物中,碱不溶物和酸可溶物内都不存在新形成的LCC结构。     

硫酸盐木素及其应用

1前言木素（又称木质素）是木板材料的主要成分之一，是一种储量丰富却没有对其充分利用的宝贵资源。木素属天然高分子化合物，具有超分子特性和高比表面积，并且还含有较多的表面活性基团，如酚羟基、苄式羟基、羰基、羧基、乙烯基等。由于这些活性基团的存在，使木素容易进行多种化学改性反应，如磺化、硫氢化、硝化、卤化、甲酸化、氰乙基化、酚化以及接技共聚等。硫酸盐水素是由硫酸盐法制浆废液中提取出来的。目前的制浆工艺所产生的废液（亦称黑液）都采用蒸发、燃烧、苛化等过程用以回收热能和烧碱，然而这一工艺只能回收占黑液于固…     

硫酸盐苇浆残余木素生物降解前后结构特征的对比研究

从元素组成 ,功能基含量 ,结构单元三种基团的比例和分子量及其分布等方面研究了生物降解纤维素酶苇浆残余木素的性质。发现生物降解后的苇浆残余木素具有较高的氧含量 ,较低的甲氧基含量、酚羟基含量和较高的醇羟基含量 ,略低的经碱性硝基苯氧化后得到的总醛含量及对羟苯基单元含量 ;另外 ,生物降解以后硫酸盐苇浆残余木素平均分子量有显著降低。     

桉木硫酸盐浆DMD漂白工艺条件的研究

使用新漂剂二甲基二环氧乙烷（Dimethyldioxirane,简称DMD）漂白桉木硫酸盐浆时,应严格控制反应的pH值为7．0~7．5;过氧硫酸盐和丙酮用量增加,二甲基二环氧乙烷的漂白能力随之增强;5％用量的DMD漂浆经碱抽提后脱木素能力与氧脱水素相当,但前者漂浆得率高,脱木素选择性好。     

自燃煤矸石作活性掺和料配制高强混凝土的试验研究

自燃煤矸石具有火山灰活性，粉状的自燃煤矸石常温下就可与碱或碱性盐发生化学反应，生成具有水硬性胶凝性能的化合物。以自燃煤矸石粉部分取代水泥配制混凝土，测定其坍落度、抗硫酸盐侵蚀性能和力学性能。结果表明：掺入自燃煤矸石粉的混凝土流动性能有所改善，抗硫酸盐侵蚀能力增强，混凝土的强度随煤矸石取代水泥量的增加而减小。取代量在20％以下时，其强度下降幅度很小。利用磨细自燃煤矸石取代20％水泥，加入适量减水剂，可以配制C60级高强混凝土。     

减水剂与低硫酸盐含量水泥的相容性

研究了硫酸盐含量不超过2.00%的胶凝材料中,硫酸盐含量变化对减水剂与胶凝材料相容性的影响规律及微观机理。通过测定0.39%～3.00%硫酸盐含量的浆体在相同流动度下的水胶比和减水剂掺量,确定硫酸盐含量降低对减水剂作用效果的影响规律。研究了减水剂的吸附行为和硫酸盐含量低于2.00%的水泥浆体早期水化产物的变化情况。结果表明:当水泥浆体中硫酸盐含量低于1.50%时,浆体硫酸盐含量的降低使水泥早期生成大量Ca(OH)2,新拌浆体Zeta电位显著提高,增加了减水剂的吸附量和早期水化产物对减水剂分子的包裹与吞噬作用。硫酸盐含量降低对低电荷密度的聚羧酸减水剂影响较小,因此,当胶凝材料中硫酸盐含量低于2.00%时,应尽量选取低电荷密度的聚羧酸减水剂,以避免相容性问题的出现。     

Parameters Affecting the Cross-Flow Filtration of Dissolved LignoBoost Kraft Lignin

In the kraft pulping process, the lignin-containing by-product kraft black liquor is currently combusted as an energy source. LignoBoost is a technique that extracts lignin from kraft black liquor, resulting in a lignin-lean black liquor, which is returned to the process, and an extracted kraft lignin. To facilitate the use of the extracted kraft lignin in high-value applications, it can be refined via fractionation to produce a more homogeneous starting raw material. Hence, the aim of this study is to investigate the behavior of dissolved softwood kraft lignin during cross-flow filtration. The effects of the lignin concentration, pH, and ionic strength on the fractionation of the dissolved lignin during cross-flow filtration are investigated. The results indicate that large amounts of low-molecular-weight kraft lignin can be produced from solutions having a low lignin concentration. Furthermore, the effects of pH and ionic strength on the fractionation of low-molecular-weight lignin are identified within the studied ranges.     

聚羧酸减水剂影响抗裂性能的机理研究

通过实验,以混凝土28d的拉压比大小为评价混凝土抗裂性能的优劣，分析了合成聚羧酸减水剂的羧基、氨基、磺酸基、羟基、酯基等各官能团比例，聚醚支链的长短，减水剂分子量大小等因素对混凝土抗裂性能的影响。初步探讨了聚羧酸减水剂提高混凝土抗劈裂性能机理。     

Kraft lignin in polyurethanes I. Mechanical properties of polyurethanes from a kraft lignin–polyether triol–polymeric MDI system

Polyurethanes with various NCO/OH ratios and kraft lignin contents were synthesized by polymerization of kraft lignin (free of the low and high molecular weight fractions), a propylene–oxide-based polyether triol and polymeric MDI in tetrahydrofuran solution. Films were made by solvent casting and tested with respect to swelling behavior and tensile properties. The main findings were: At low NCO/OH ratios, kraft lignin contributed effectively to the formation of the three dimensional network; under particular conditions of NCO/OH ratio and kraft lignin content, polyurethanes of considerable toughness were obtained; at high kraft lignin contents, the obtained polyurethanes were hard and brittle regardless of the NCO/OH ratio used.     

Modified Kraft Pulping of Bagasse: Infrared Spectroscopy of Lignin

Abstract

The infrared spectroscopy of precipitated lignin from waste black liquors of bagasse pulping with kraft sulfite pulping process was investigated. Also the effect of anthraquinon and methanol addition in the soda, kraft and kraft-sulfite pulping liquor on the infrared specra of the precipitated lignin was studied. The presence of methanol in the pulping liquor causes an increase in the degradation as well as increase in the carboxylic group in the precipitated lignin. Also, the phenolic hydroxyl group in case of kraft lignin is higher than soda lignin. Presence of sulfite in the kraft-sulfite pulping liquor produces lignin hydroxyl groups.     

漆酶与助剂氧化体系降解苇浆残余木素的研究

用溶剂抽提法制取了苇浆残余木素 ,用漆酶 /助剂和氧气与其反应 ,通过甲氧基的测定、元素分析、1 3C -NMR、1 H -NMR和IR分析研究苇浆残余木素与漆酶 /助剂反应前后结构的变化。研究发现苇浆残余木素在反应后其甲氧基、酚羟基减少 ,醇羟基增多 ,木素结构中羰基增多 ,木素的苯环结构发生了开环反应     

Origin and Nature of Kraft Colour: 1 Role of Aromatics

The chromophores responsible for kraft colour have been generally assumed to be derived from the aromatic portions of the lignin molecule. Analytical studies of the high molecular weight dissolved materials from kraft lignin, kraft cooked sugars, and extraction stage effluent by pyrolysis GC-MS, permanganate/periodate oxidation, and UV-visible spectroscopy showed that these materials had a wide variation in aromatic content but similar spectral properties. It is now proposed that carbohydrate degradation products produced by the kraft cooking of sugars are primarily responsible for the kraft colour.     

芦苇硫酸盐浆残余木素特性的研究

从元素组成、功能基含量、结构单元三种基的比例和分子量及其分布等方面研究了苇浆残余木素的性质 ,并与芦苇木素进行了比较。研究发现 ,苇浆残余木素比起芦苇木素具有较高的氢含量和较低的氧含量 ;较低的甲氧基含量和较高的酚羟基和醇羟基含量 ;明显低的总醛含量、平均分子量及更高的多分散性。     

Kraft lignin in phenol formaldehyde resin. Part 1. Partial replacement of phenol by kraft lignin in phenol formaldehyde adhesives for plywood

The objective of this study was to investigate the potential for partially replacing phenol with kraft lignin in the phenol formaldehyde (PF) resin designed for application as an adhesive in the production of plywood. The kraft lignin, considered to be an environmentally friendly alternative to phenol, was precipitated from black liquor recovered from kraft pulping of softwood. Kraft lignin phenol formaldehyde (KLPF) resin was prepared in a one-step preparation with different additions of lignin. Replacing 50 wt% of the phenol with kraft lignin (50KLPF) was, under the conditions used, considered to be optimal with respect to resin viscosity, storage stability, and bonding ability. The resin consists of an integrated kraft lignin-phenol network. The hot-pressing time in the plywood manufacturing had to be increased by approximately 30% at 150°C for the 50KLPF resin compared with that normally used for PF resin, in order to comply with plywood standard demands. The mechanical properties of test samples made from KLPF resins were equal to or better than those of test samples made from PF resin only.     

Polyurethane from kraft lignin

The condensation of lignin with hexamethylene diisocyanate (HDI) or of a mixture of lignin-poly(ethylene oxide) (PEO) with HDI was investigated. The lignin used in this study was a kraft lignin from Pinus maritima, and was obtained from black liquor by acidification, filtration and vacuum drying. Thermogravimetric analysis was carried out to compare the weight loss against temperature of polyurethanes based on kraft lignin and hexamethylene diisocyanate, or of mixed polyurethanes lignin-PEO-HDI, with that of kraft lignin alone. It was shown that lignin can react with isocyanates in rather mild conditions to give polyurethanes, confirming previous results performed with model molecules. Some mechanical properties (Young's modulus and rupture strength) and glass transition temperature were also measured on the various above materials. In all cases it was concluded that lignin participates to the polycondensation reaction. As to rigid foams, it was found that polyurethanes prepared with oxypropylated glycerol, ethylene glycol and kraft lignin, in the weight proportions of 100/30/15, and HDI had good dimensional stability, and thermal and mechanical properties comparable to those of equivalent industrial materials.     

工业碱木素热化学转化制备酚类化学品

引言 工业碱木素是碱法制浆过程中产生的重要副产物之一,其排放污染问题越来越受到关注,目前工业处理方法只是将其浓缩燃烧以回收能源和残碱.木质素是一种化学结构复杂的天然高分子聚合物(主要由愈创木基丙烷、紫丁香基丙烷和对羟苯基丙烷通过醚键和碳碳共价键相联),其分子量从几千至几十万,数量上仅次于纤维素,利用潜力较大.