淀粉/木质素复合膜的制备与性能研究

为了提高淀粉基膜材料的疏水性,本文对淀粉/木质素膜的制备方法与性能进行了研究。研究结果表明,山梨醇的用量、木质素的用量和反应温度对淀粉/木质素膜的吸水率都有明显影响,优化的制备工艺为m淀粉∶m木质素为9∶1,m淀粉∶m山梨醇=9∶8,反应温度为70℃,在此条件下制备的淀粉/木质素膜的吸水率为49.85%。制得的淀粉/木质素膜较致密,组分间相容性好,在90℃以下有较好的热稳定性。     

木质素磺酸钠Langmuir-Blodgett膜的制备与表征

为了深入研究木质素磺酸钠在气/液界面上的吸附特性,采用Langmuir-Blodgett(LB)膜天平成功地将木质素磺酸钠Langmuir膜以Y-型膜转移到固体石英玻片上,并采用紫外分光光度仪对其表征。通过研究木质素磺酸钠的π-A曲线得出其LB膜的制备条件:溶液浓度为10 g·L-1,亚相为0.01 mol·L-1 CdCl2,进样量为50μL,划障速率为10mm·min-1。通过添加5%(wt)的脂肪醇与木质素磺酸钠形成复合物,改变了木质素磺酸钠的分子构型,促使更多的木质素磺酸钠分子吸附于气/液界面,形成排列更加有序的Lamgmuir膜,长链脂肪醇对木质素磺酸钠吸附性能具有一定的促进效果,其促进效果随着醇的碳链增长而增强。     

木质素/壳聚糖共混膜的制备及对Cu~(2+)的吸附性能

以木质素和壳聚糖为原料,通过共混的方法制备了木质素/壳聚糖共混膜。对膜的物理性能分析表明:膜的平均厚度为0.196 mm,厚度均一;吸水溶胀率为3.76%。采用SEM对膜的微观形貌分析表明,膜的表面有均匀凸起。对Cu~(2+)的吸附性能分析表明,木质素/壳聚糖共混膜对Cu~(2+)的饱和吸附量为106μg/cm2。     

木质素基材料的研究及应用进展

本文对木质素在合成树脂、吸附剂、膜材料及农业肥料方面的研究和应用进行了阐述,并针对木质素的结构和性能,提出改性木质素将成为大力发展木质素基材料的研究重点。     

木质素酚醛树脂炭膜的CP/MAS 13C NMR表征

采用固体核磁共振技术CP/MAS 13C NMR分析了木质素酚醛树脂炭膜。结果显示木质素含量的变化影响到炭膜的结构,如:炭膜中侧链烷基碳、非酚型紫丁香基和羟甲基碳结构。     

木质素酚醛树脂炭膜的CP／MAS ^13C NMR表征

采用固体核磁共振技术CP/MAS 13C NMR分析了木质素酚醛树脂炭膜.结果显示木质素含量的变化影响到炭膜的结构,如炭膜中侧链烷基碳、非酚型紫丁香基和羟甲基碳结构.     

木质素基活性炭的制备与电容性能研究

以废物利用,保护环境为出发点,以KOH活化得到木质素基活性炭,以其作为电极材料制作电极,通过测试超级电容器双电层电容的充放电特性、阻抗等电化学性能来评估木质素活性炭的电化学性能和应用前景。通过改变木质素与KOH质量比,比较不同质量比下,得到测试结果最优质量比,也进行木质素基活性炭膜与木质素基活性炭电极比较,分析活性炭膜的优异性能,通过结果表明,木质素与KOH的比例为15:1时,活性炭电容量达到147Fg-1,且具有良好导电性。     

木质素网状聚氨酯泡沫的制备及初步应用

介绍了木质素网状聚氨酯泡沫的制备方法,着重讨论了溶剂对木质素在聚氨酯基体中分布的影响、木质素对聚氨酯软质泡沫的泡孔和力学性能的影响。实验结果表明:木质素的加入可以提高聚氨酯软质泡沫的开孔率,当木质素的质量分数在2%时,可使网化泡沫拉伸强度最高达0.12MPa;当木质素的质量分数在5%时,可使网化泡沫伸长率最高达374.3%;木质素质量分数为5%和8%的聚氨酯软质泡沫经过30d的挂膜测试,最终挂膜量分别达10000mg/L和12100mg/L,可以作为污水处理填料使用。     

PBAT/PLA/木质素流延膜的制备、表征及性能研究

首先对木质素进行了结构和粒径尺寸分析,得到的木质素尺寸为微米级,结构中含磺酸基团,分析的物质为磺化木质素。其次,通过熔融挤出制备了聚己二酸-对苯二甲酸丁二醇酯(PBAT)/聚乳酸(PLA)/木质素复合材料,将其制备成流延膜,对膜材的热性能、力学性能进行研究。结果表明,通过对碳酸钙的同等份数替代,添加铝酸酯偶联剂的复合材料的结晶温度向高温移动,有利于提高木质素在基体中的分散性和相容性,膜材的纵向拉伸负荷提高了5.2 N,断裂应变提高了261%,撕裂负荷提高了0.6 N。     

竹浆黑液高效减水剂与木质素磺酸钠的吸附行为对比

通过对比竹浆黑液高效减水剂(GCL1-JB)与木质素磺酸钠(SL)在固体平板上的吸附行为探究二者分散性能差异的原因。采用石英晶体微天平和逐层自组装技术研究GCL1-JB与SL的吸附行为,对比了GCL1-JB和SL在固体平板上的吸附量、吸附膜厚度、吸附层结构等。结果表明,相比于木质素磺酸钠,GCL1-JB的吸附量较多,吸附膜较厚,吸附层结构较致密,膜表面较平整光滑,吸附在水泥颗粒表面后的zeta电位较大。因此GCL1-JB有较强的空间位阻和静电排斥作用,导致GCL1-JB的分散性能优于木质素磺酸钠。研究有助于理解木质素基减水剂的分散机理,为木质素改性成减水剂提供理论基础。     

AHP/碱木质素聚氨酯泡沫的阻燃性能

对精制后的碱木质素进行羟甲基化改性,再利用改性后的羟甲基化碱木质素部分替代聚醚多元醇,采用一步发泡法与聚合MDI制备了羟甲基化木质素基聚氨酯泡沫材料。将次磷酸铝(AHP)作为阻燃剂添加到泡沫中制备了阻燃碱木质素聚氨酯泡沫,通过极限氧指数(LOI)测试分析了羟甲基化木质素基阻燃聚氨酯泡沫的阻燃性能。利用热重分析(TG)和扫描电子显微镜(SEM)分别研究制得泡沫的热降解行为、成炭性能和残炭形貌。实验结果表明,当羟甲基化碱木质素替代聚醚多元醇的量为60%,次磷酸铝的添加量为30%时,碱木质素聚氨酯泡沫材料的极限氧指数(LOI)值达到了27.5%。因此,羟甲基化碱木质素和次磷酸铝使泡沫在燃烧时能更好的形成炭层,从而有效地隔绝空气,降低热传递,提高了材料的阻燃性能。     

木质素酚醛树脂碳纤维的制备及表征

用不同比例的木质素与甲醛、苯酚合成酚醛树脂,并进一步制备成碳纤维。应用热失重和元素分析研究了木质素酚醛树脂的碳化过程,结果表明,木质素的加入提高了树脂的热性能,降低了树脂的热降解程度。应用扫描电镜研究了木质素酚醛树脂碳纤维的微观结构,研究发现木质素含量的不同对碳纤维内部的微孔孔径具有可控作用。     

原料复配制备木质素基成型活性炭研究

以碱木质素和杉木屑为原料,磷酸为活化剂,制备碱木质素基成型活性炭,考察了碱木质素质量分数、浸渍比、活化温度、活化时间等对活性炭性能的影响。研究结果表明：碱木质素复配杉木屑(碱木质素质量分数50%)后,复配料的表面润湿性显著提高,瞬时水接触角由133.2°(碱木质素)降低至86.6°(复配料);热膨胀系数显著降低,膨胀温度区间的热膨胀系数由2 365μm/(m·℃)(碱木质素)降低至45μm/(m·℃)(复配料)。在最佳工艺条件即碱木质素质量分数50%、浸渍比1.5∶1(纯磷酸与复配料质量比)、活化温度500℃、活化时间90 min下,制备的成型活性炭得率41.76%,碘吸附值1 070 mg/g,亚甲基蓝吸附值255 mg/g,强度90%,比表面积1 646 m²/g,总孔容积为0.795 cm³/g,其中孔径小于5 nm的孔容积占总孔容积的97.2%。     

木质素用量对乳液共沉天然橡胶性能的影响

采用共沉方法制备天然橡胶/木质素复合材料,研究了复合材料和炭黑胶料的性能以及木质素用量对天然橡胶性能的影响。结果表明,加有木质素的胶料,随着木质素用量的增加,复合材料的门尼粘度逐渐上升,炭黑胶料的最低转矩(ML)增大,最高转矩(MH)下降,正硫化时间(tc90)延长,焦烧时间(ts1)缩短,炭黑分散性变差,胶料的加工安全性、耐磨性及耐老化性变差,硫化胶的定伸应力降低。当木质素用量在20份以内时,硫化胶的拉伸强度和撕裂强度提高。     

Carbon nanofibers from renewable bioresources (lignin) and a recycled commodity polymer [poly(ethylene terephthalate)]

Utilizing inexpensive biorenewable and waste raw materials for the production of carbon nanofibers can pave the way for lowering their manufacturing cost. In this research, lignin is combined with recycled poly(ethylene terephthalate) (PET) to fabricate precursor fibers via electrospinning. The process is optimized using the Design of Experiments statistical methodology and fibers with minimum average diameter equal to 191 ± 60 nm are prepared. Investigation with Attenuated Total Reflection – Fourier Transform Infrared Spectroscopy reveals the lignin structural changes induced by the solvent (trifluoroacetic acid), which is used for the preparation of homogeneous solutions of lignin and PET in various concentrations, while it gives an indication of the blending of the two electrospun polymers. The good miscibility between lignin and PET is also confirmed with Differential Scanning Calorimetry. The subsequent carbonization of the precursor fibrous mats results in a fibrous carbon structure with average fiber diameters similar to those of the precursor fibers. The successful transformation into carbon nanofibers is affirmed by Energy Dispersive X‐ray Spectroscopy. The Carbon content of these nanofibers amounts to 94.3%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43936.     

Lignin–silica hybrids as precursors for silicon carbide

Lignin, prepared by digesting cedar with acetic acid, and tetraethoxysilane have been allowed for a sol–gel reaction in tetrahydrofuran using H₂SO₄ as catalyst to yield lignin–SiO₂ hybrids in the bulk gel form. The solid-state ¹³C nuclear magnetic resonance spectra of the hybrids and products formed solely from the lignin under the acidic conditions revealed that the lignin underwent crosslinking during the sol–gel reaction. The degree of crosslinking increased with an increasing amount of H₂SO₄. The powdered hybrids have been heated at 1500°C in Ar for carbothermal reduction, resulting in the formation of SiC powders. The lignin-to-tetraethoxysilane mixing ratio of the starting solutions varied free carbon content in the SiC powders. In addition, the amount of carbonaceous residue formed from the lignin upon heating depended on the degree of crosslinking of the lignin. Thus, to adjust the amounts of both the lignin and H₂SO₄ was necessary for producing the hybrids suitable for precursors for SiC powders with high purity. Critical adjustment of the amounts led to the formation of SiC powders with a free carbon content of 0.57 wt %, implying that the lignin is a beneficial carbon source for the production of SiC powders by the hybrid route. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1321–1328, 1999     

一步法制备富氧木质素活性炭及其亚甲基蓝吸附性能

以硫酸盐造纸黑液木质素为原料,分别采用磷酸活化和磷酸、硫酸混合酸活化制备了两类不同结构的木质素活性炭,对其进行了扫描电镜（SEM）、红外光谱（FTIR）、氮气吸附脱附、元素分析和Boehm酸值滴定等表征分析,并将制备的活性炭应用于模拟亚甲基蓝（MB）染料废水的吸附。结果表明,混合酸活化制备的木质素活性炭比单独磷酸活化的木质素活性炭的比表面积、总孔体积、介孔体积、氧含量分别增加了27.9%、26.4%、29.3%和29.2%,并且孔径分布更趋集中。混合酸活化活性炭在pH为2~9的范围内对亚甲基蓝均有优异的吸附性能,最大饱和吸附量达到1118.90 mg·g^-1,比磷酸活化木质素活性炭的吸附量增加了20.3%,表现出良好的吸附性能。吸附速率快,吸附过程遵循Langmuir等温线和伪二级动力学方程,颗粒内扩散不是唯一的决速步骤。     

A new carbon fiber from lignin

A new carbon fiber was prepared from the lignin (steam-exploded lignin), which was isolated from steam-exploded birch wood (Betula platyphylla). The lignin was modified to melt thermally on hydrogenolysis. The chloroform soluble and carbon disulfide insoluble fraction (HL) of the reaction products was heated at 300–350°C for 30 min, giving a molten viscous material (HHL). The HHL had a softening point of 110°C and melted at over 145°C to form viscous liquid. When HHL was subjected to a spinning test, according to a conventional fusion spinning method at a speed over 100 m/min, a fine filament could be continuously formed through a pinhole (diameter: 0.3 mm). After the filaments were heated in air at 1–2°C/min up to 210°C, by which time the filament was converted to have an infusible property, the filaments were carbonized by heating from a room temperature to 1000°C at a heating rate of 5°C/min in a stream of nitrogen. The typical properties of the lignin based carbon fiber were as follows: Fiber diameter = 7.6 ± 2.7μ Elongation = 1.63 ± 0.29% Tensile strength = 660 ± 230 MPa; Modulus of elasticity = 40.7 ± 6.3 GPa. The chemical structure of the precursor was remarkably changed from that of the original lignin, indicating the elimination of aliphatic functional groups implied originally in the starting material.     

Shell–core structured carbon fibers via melt spinning of petroleum- and wood-processing waste blends

In the last decades, carbon fibers with light weight and high strength have experienced the largely increased uses in various industrial applications. However, their expected uses in the automotive industry and building are largely limited because of their high production cost. Herein, we have demonstrated an effective method of making low cost carbon fibers via the melt spinning of petroleum-processing residue (pyrolyzed fuel oil, PFO)/lignin blends. Careful selection of tetrahydrofuran as the solvent to dissolve both PFO and lignin was made to optimize the miscible blend. The melt spinnable blend with a softening point of 260–280 °C exhibited good spinning ability at 280 °C. The plasticizing function of PFO allowed the highly cross linked lignin-based pitch to have high fluidity in the melt spinning process. Based on detailed TEM observations, the thermally treated fiber prepared at 2800 °C exhibited a shell–core structure, consisting of a highly crystalline surface from PFO and an amorphous disordered core from lignin. Such a crystalline surface structure gave rise to a high modulus value (up to 100 GPa) to the prepared carbon fibers.     

木质素基功能材料的制备与应用研究进展

木质素是植物中含量第二大的天然有机高分子聚合物,以来源于制浆造纸和生物质炼制中的工业木质素为原料,制备具有特殊功能的高附加值材料,对木质素进行资源化高效利用、解决化石资源日趋紧缺及环境污染等问题具有重要意义。近年来,研究人员利用各种技术制备了许多种类的木质素基功能材料,如载药微胶囊、防紫外剂、抗老化剂、光催化剂载体、炭电极材料等。本文介绍了木质素基功能材料的国内外最新研究进展,总结了木质素基功能材料的不同制备工艺和应用领域,评述了木质素微观结构及制备工艺对材料结构特性和应用性能的影响。指出木质素基功能材料的研究是涉及多个学科交叉的前沿课题,但如何高效制备结构规整可控且性能优异的木质素基功能材料仍然是一个具有挑战性的课题。今后的研究应加强对木质素微观结构及其调控机理的研究,以便可以更好地利用其自身的三维网状结构和大量芳香结构等特性制备基于木质素特性的功能材料。