木质素先进材料的研究进展

综述了木质素改善合成高分子材料的性能和制备光电材料、阻燃材料、电磁屏蔽材料等方面的研究进展。加强木质素结构和性能的基础研究,解决木质素反应活性偏低以及与基体相容性差的问题,将木质素的耐辐射、可生物降解、阻燃、电磁屏蔽等特异性能引入到传统合成高分子材料中,制备性能优异、功能多样的先进高分子材料,是木质素高值化利用的一个重要方向。     

木质素活化改性制备酚醛树脂胶黏剂研究进展

木质素由于化学结构与苯酚相似,通过活化改性可部分替代苯酚制备木质素改性酚醛树脂胶黏剂。既可降低成本、达到生物质资源高效利用的目的,并且制备的木质素改性酚醛树脂胶黏剂有毒残余较低,具有环保意义,是合成制备生物质高分子材料的重要途径。本文综述了国内外研究人员在木质素活化改性制备酚醛树脂胶黏剂研究领域的最新进展,重点介绍了化学改性、物理改性、生物改性等木质素活化改性方法,比较了不同改性产物制备酚醛树脂胶黏剂的性能,并对影响木质素活化改性制备酚醛树脂胶黏剂实现工业化应用的主要因素进行了分析。     

木质素磺酸盐表面活性剂的研究和应用进展

论述了木质素磺酸盐结构方面的研究、木质素磺酸盐的分离纯化和化学改性制备表面活性剂的方法、木质素磺酸盐表面活性剂应用取得的进展和研究面临的挑战。最后总结认为:进一步加强木质素磺酸盐结构和性能的基础研究,结合界面化学的最新理论成果和现代分析测试手段,通过改性解决木质素磺酸盐的颜色和活性问题,开发可用于日用领域的新型环保的木质素磺酸盐表面活性剂,是木质素磺酸盐这一绿色资源得到高值化利用的一个重要方向,同时木质素磺酸盐在导电高分子等先进材料制备领域具有重大的研究潜力。     

原子转移自由基聚合接枝改性木质素

木质素是仅次于纤维素的第二大生物质资源, 是自然界中唯一的可再生芳香族化合物资源。长久以来, 木质素的难以充分利用是掣肘生物化工产业的一个重大问题。近年来, 原子转移自由基聚合接枝改性成为木质素高值化利用的一个重要方法, 可制备获得不同结构、性能各异的木质素接枝改性材料。本文从单体种类、催化剂、材料的结构与性能等方面, 介绍了原子转移自由基聚合接枝改性木质素的研究进展, 并对该领域的发展前景与挑战进行了探讨。     

木质素及其在高分子材料方面的利用课程教学方法与实践

木质素是一种重要的天然高分子,其开发利用已成为材料科学的热点之一。木质素及其在高分子材料方面的利用课程内容涉及木质素的结构与性质、木质素化学品、木质素热固性材料、木质素热塑性材料、木质素新材料、木质素材料的性能评价等。针对该门课程知识点多且内容分散、知识面宽、知识点新的特点,提出了教学方法:(1)采用案例教学法,密切联系生产实践;(2)采用翻转课堂教学法,提高学生自学能力;(3)加强双语教学,培养国际化专业人才;(4)采用灵活有效的考核方式,着实提高学生综合能力。     

木质素的功能化与应用研究进展北大核心CSCD

木质素是地球上一类含量丰富且重要的天然高分子材料,其地位仅次于纤维素。在木本植物中,木质素的质量分数达到25%。由于木质素的化学惰性和结构复杂性,其实际应用受到了很大的限制。因此,利用化学方法对木质素进行结构改性是将木质素转化为木质素基功能材料的有效途径,对实现资源和环境的可持续发展有着重要意义。本文综述了近10年来木质素功能化发展和应用的相关研究进展,重点介绍了木质素在污水处理、异相催化以及阻燃等方面应用的研究成果,并对该领域未来的研究提出思考和展望,为后续更加深入的研究提供相关的依据和参考。     

高分子材料接枝抗菌功能改性方法研究现状

近年来,接枝抗菌改性因其可以在不改变高分子材料原本特性的条件下使其具备优异抗菌性能而备受关注,通过接枝抗菌改性的高分子材料被广泛应用于生活中的各个领域。本文综述了目前国内外高分子材料接枝抗菌改性中常用的一些抗菌基团(N-卤代胺结构的物质、带正电的抗菌活性物质等),介绍了这些抗菌基团在高分子材料中起到的抑菌效果及其抑菌机制,并对接枝抗菌改性高分子材料未来的发展趋势进行展望。     

基于ATRP接枝改性木质素的研究进展

木质素是仅次于纤维素的第二大可再生生物质资源,也是一种环境友好的有机高分子材料.原子转移自由基聚合(atom transfer radical polymerization,ATRP)是近年来迅速发展并有着重要应用价值的一种"活性"/可控自由基聚合技术.本文结合本课题组目前的研究工作和近几年的相关报道,简述了ATRP在木质素接枝共聚方面的最新研究进展.综述了采用ATRP对木质素接枝共聚改性的方法,并采用该方法在木质素表面接枝不同功能性单体,赋予木质素表面温敏性、离子响应性、气体开关和基因传递等多种特殊性能的研究概况.最后介绍了AGET ATRP(activators generated by electron transfer ATRP)在木质素接枝共聚反应中的应用.     

高分子材料的生物降解性能表征

生物降解能够使高分子材料回归自然界物质循环,被认为是解决塑料污染的一大重要途径.高分子材料的生物降解性能表征对相关材料开发、改性和产业应用十分重要.本文针对高分子材料的需氧生物降解,从降解产物和降解残留材料两个方面介绍常用表征方法 .降解产物的表征主要从CO2生成量、O2消耗量和小分子产物三方面开展,降解残留材料的表征围绕其组成结构变化和性能变化.介绍了各表征方法的简单原理和典型案例,并对未来发展进行了展望.     

二维高分子的制备、组装及其高效电化学应用

二维高分子是通过共价键连接的在二维平面内具有周期性排列结构的分子片,因其具备质轻、柔性、可调结构和高适应性等优点近年来受到了国内外研究学者的广泛关注.可控制备二维高分子对于研究二维高分子的结构与性能关系、合成特定功能化改性的二维高分子具有重要的意义.本文以本课题组的研究工作为出发点首先围绕一种天然二维高分子材料(石墨烯...     

木质素酚类单体化合物制备烷烃燃料

通过引入中间小分子化合物,采用傅克烷基化反应,实现了从木质素酚类单体化合物制备长链烷烃燃料.考察了催化剂、醛酮类小分子化合物、反应时间、反应温度、物料比、底物等条件对从木质素酚类单体制备二聚体反应结果的影响,并对得到的木质素酚类二聚体产物进一步加氢还原,得到C_13~19烷烃燃料.结果表明,当物料比n(木质素酚类单体)/n(醛酮类中间小分子)为15:3,以Amberlyst-15为酸性催化剂,在100 ℃的条件下,反应24 h,可以得到68%产率的二聚体化合物(当底物是愈创木酚和丙醛时).将得到的二聚体化合物在270 ℃,4 MPa H₂的不锈钢反应釜中进行加氢反应,3 h后,二聚体化合物完全转化为液体烷烃.提出从木质素单体出发通过引入中间小分子,实现C-C链增长来制备烷烃燃料的合成路线,为木质素的开发和应用提出了新思路与实验基础.     

The catalytic oxidation of biomass to new materials focusing on starch,cellulose and lignin

Biomass is a renewable class of materials of growing interest amongst researchers aiming to achieve global sustainability. This review focuses on the homogeneous catalysis of the oxidation of biomass, in particular starch, cellulose and lignin. Often such catalytic reactions lead to depolymerisation of the material as happens in Nature with for example brown rot fungi. This depolymerisation can be desirable or not, and control in industrial applications is thus important to obtain the desired outcome. The two main oxidants in use are O₂ and H₂O₂ and their use is described as appropriate. Industrial oxidation catalysis is highly significant in the bleaching of cellulose-containing materials due to its high volume application in the paper, pulp and laundry industries. Here, the presence of a ligand on the oxidising metal ion has a significant effect on the catalyst selectivity and stability. In addition to the bleaching of cellulose-containing materials, the oxidation of cellulose, starch, lignin and lignin model compounds are discussed with a focus on generating even more hydrophilic materials which have important applications or materials which may be further modified. Finally developing applications of biomass are described such as new support materials for catalysts, as supports for sensors and nanomaterials for microbial culture.     

The first 85% kraft lignin-based thermoplastics

Interest in the development of lignin-containing polymeric materials has been upheld more or less continuously for the past 20 years. Tendencies toward high moduli and poorly defined thermal transitions have been regarded as imposing inevitable limitations upon the use of lignin derivatives for such purposes. Incorporation of more than 25–40% (w/w) lignin had usually resulted in materials that were brittle and weak. For the first time, however, from homogeneous blends containing 85% (w/w) underivatized industrial kraft lignin with poly(vinyl acetate) and two plasticizers, a series of thermoplastics has been fabricated with promising mechanical properties. The tensile behavior of these new polymeric materials depends directly upon the degree of association between the intrinsic kraft lignin components. In extending to values about 25 MPa and 1.5 GPa, respectively, the tensile strengths and Young's moduli vary linearly with the effective M̄_w for the kraft lignin species, under conditions where the proportions of the individual molecular components, both associated and discrete, do not change. Moreover, melt-flow index measurements indicate that these polymeric materials are amenable to thermal processing by extrusion molding. Thus a significant step has been taken toward developing a new generation of thermoplastics that are lignin-based in a very fundamental way. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1899–1910, 1997     

Quaternized lignin-based dye dispersant: Characterization and performance research

Lignin-based dye dispersants have aroused an increasing interest due to their environment-friendly properties. In this research, the quaternized lignin-based dye dispersant (QLD) was prepared using alkali lignin from masson pine sulfate pulping liquor as raw materials by chemical modification, that is, sulfonation and quaternization. The structure and performance characterization of alkali lignin and QLD were studied. The analyses indicated that the structural unit of alkali lignin contained more G type and S type. Additionally, it was also proved that QLD contained quaternary ammonium group, amine group, and sulfonic group, which could improve the dispersion performance and thermostability of QLD. The results of thermogravimetric (TG) concluded that the dispersion performance and thermostability of QLD prevailed over alkali lignin. Compared with the contact angle of water, alkali lignin, and QLD with dye, the contact angle of QLD was much better than water and alkali lignin, indicating that the hydrophilicity and dispersion performance of QLD were superior to water and alkali lignin in Vat Olive T.     

Influence of lignin on cellulose-NaOH-water mixtures properties and on Aerocellulose morphology

Microcrystalline cellulose and organosolv lignin, both dissolved in 8%NaOH-water, were mixed with the objective to study the influence of lignin on the properties of cellulose solutions and on the morphology of dry porous materials. Mixture viscosity and gelation were investigated. Cellulose-lignin gels were regenerated in aqueous acid baths and dried under supercritical CO₂ to obtain Aerocellulose, an aerogel-like material. The presence of lignin in the mixture speeded up gelation. During regeneration part of lignin was washed out. This created large pores and channels in the dry materials. The overall results obtained showed that cellulose and lignin are not compatible in the solvent used.     

植物纤维及其提取物增强聚合物的3D打印成型研究

3D打印技术作为新型成型技术,近年来受到了巨大的关注,但常见的PLA、ABS等单体打印耗材由于其自身的不同缺点,限制了其进一步的应用。本文综述了植物纤维及其提取物增强聚合物复合材料在3D打印领域的应用研究进展,重点阐述了木纤维、竹纤维,秸秆纤维等常见植物纤维用于3D打印的研究现状,还介绍了纤维素、木质素、半纤维素等植物纤维提取物增强聚合物用于3D打印的研究情况。同时对植物纤维/聚合物材料存在的一些问题及改性方法进行了分析与展望。     

Graphite from hydrolysis lignin: Preparation procedure,structure, properties,and application

The possibility of preparing graphite from hydrolysis lignin using pyrolysis and graphitization processes was considered. The influence of lignin milling on the granulometric composition of the graphite obtained was studied. The structure of graphite prepared from lignin was confirmed by X-ray diffraction analysis. Prospects for using graphite materials prepared from lignin in electrochemical and other technologies are demonstrated.     

Thermochemistry of lignin

Thermochemical reactions occurring in various stages of structural transformations of native lignin in its thermal treatment in a wide temperature range are considered and classified. Attention is given to the initial state of lignin in its primary isolation without heating. The terminology of lignin products, used in the literature, is put in order to a certain extent. The thermochemical reactions in which lignins are transformed in processing of raw wood materials and the structure of isolated lignins undergoes changes in the course of the target thermal treatment are differentiated. The applied aspect of the directed thermochemical synthesis of new lignin-based low- and high-molecular-mass compounds is discussed.     

Reductive catalytic fractionation of pine wood: elucidating and quantifying the molecular structures in the lignin oil

In-depth structural analysis of biorefined lignin is imperative to understand its physicochemical properties, essential for its efficient valorization to renewable materials and chemicals. Up to now, research on Reductive Catalytic Fractionation (RCF) of lignocellulose biomass, an emerging biorefinery technology, has strongly focused on the formation, separation and quantitative analysis of the abundant lignin-derived phenolic monomers. However, detailed structural information on the linkages in RCF lignin oligomers, constituting up to 50 wt% of RCF lignin, and their quantification, is currently lacking. This study discloses new detailed insights into the pine wood RCF lignin oil''s molecular structure through the combination of fractionation and systematic analysis, resulting in the first assignment of the major RCF-derived structural units in the ¹H–¹³C HSQC NMR spectrum of the RCF oligomers. Specifically, β-5 γ-OH, β-5 ethyl, β-1 γ-OH, β-1 ethyl, β-β 2x γ-OH, β-β THF, and 5-5 inter-unit linkages were assigned unambiguously, resulting in the quantification of over 80% of the lignin inter-unit linkages and end-units. Detailed inspection of the native lignin inter-unit linkages and their conversion reveals the occurring hydrogenolysis chemistry and the unambiguous proof of absence of lignin fragment condensation during proper RCF processing. Overall, the study offers an advanced analytical toolbox for future RCF lignin conversion and lignin structural analysis research, and valuable insights for lignin oil valorization purposes.

In-depth structural analysis of pine wood RCF lignin discloses new detailed insights into the RCF lignin oil''s molecular structure.