Nitration of Wood Cellulose in HNO_3/Organic Solvent Medium

A steam explosion pretreatment at various severities was applied to pure wood cellulose; the influences of steam pretreatment on the morphological structure, the hydrophilic property and viscosity-average molecular weight of cellulose were evaluated. The nitration of steam-exploded cellulose was carried out in the nitrating agent medium （HNOa/organic solvent）. The performance indexes of nitrocellulose, prepared from original and steam exploded samples, were determined by using the polarized optical microscope. The results show that after pretreatment the reactivity of the three hydroxyl groups in anhydroglucose unit of cellulose is improved, and the nitrogen content and the uniformity of NC from steam exploded cellulose observably increas.

Isolation of Microcrystalline Cellulose from Wood and Fabrication of Polylactic Acid(PLA)Based Green Biocomposites

An innovative microcrystalline cellulose(MCC)natural fibre powder-reinforced PLA biocomposite was investigated using the hand lay-up technique.The polymer matrix composite(PMC)samples were prepared by varying the weight percentages(wt.%)of both PLA matrix and MCC reinforcement:pure PLA/100:0,90:10,80:20,70:30,60:40 and 50:50 wt.%,respectively.From the results obtained,MCC powder,with its impressive aspect ratio,proved to be an ideal reinforcement for the PLA,exhibiting exceptional mechanical properties.It was evident that the 80:20 wt.%biocomposite sample exhibited the maximum improvement in the tensile,flexural,notched impact,compressive strength and hardness by 28.85%,20.00%,91.66%,21.53%and 35.82%,respectively compared to the pure PLA sample.Similarly,during the thermogravimetric analysis(TGA),the same 80:20 wt.%biocomposite sample showed a minimum weight loss of 20%at 400℃,among others.The morphological study using Field Emission Scanning Electron Microscopy(FE-SEM)revealed that the uniform distribution of cellulose reinforcement in the PLA matrix actively improved the mechanical properties of the biocomposites,especially the optimal 80:20 wt.%sample.Importantly,it was evident that the optimal PLA/cellulose biocomposite sample could be a suitable and alternative sustainable,environmentally friendly and biodegradable material for semi/structural applications,replacing synthetic and traditional components.

Wood By-Products as UV Protection:A Consequence Review

In recent decades,the ozone layer has suffered considerable damage,increasing the entry of ultraviolet(UV)light into the atmosphere and reaching the earth’s surface,negatively affecting life.Accordingly,researchers aimed to solve this problem by synthesizing advanced UV-shielding materials.On the other hand,developing an easy and green strategy to prepare functional materials with outstanding properties based on naturally abundant and environmentally friendly raw materials is highly desirable for sustainable development.Because biomass-derived materials are sustainable and biodegradable,they present a promising substitute for petroleum-based polymers.The three main structural constituents of the plant biomass-based materials that are naturally available are cellulose,hemicellulose,and lignin.This review details current developments using wood-based products such as cellulose,hemicellulose,and lignin in UV-shielding applications.It will start with assembling the structure and chemistry of cellulose,hemicellulose,and lignin,followed by their contributions to preparing UV-shielding materials.Finally,it will briefly discuss the different processing methods for the design of UV-shielding materials.The wood by-products offer additional opportunities to use the whole tree harvest.

Perturbation of Wood Cellulose Synthesis Causes Pleiotropic Effects in Transgenic Aspen

Genetic manipulation of cellulose biosynthesis in trees may provide novel insights into the growth and development of trees. To explore this possibility, the overexpression of an aspen secondary wall-associated cellulose synthase （PtdCesAS） gene was attempted in transgenic aspen （Populus tremuloides L.） and unexpectedly resulted in silencing of the transgene as well as its endogenous counterparts. The main axis of the transgenic aspen plants quickly stopped growing, and weak branches adopted a weeping growth habit. Furthermore, transgenic plants initially developed smaller leaves and a less extensive root system. Secondary xylem （wood） of transgenic aspen plants contained as little as 10% cellulose normalized to dry weight compared to 41% cellulose typically found in normal aspen wood. This massive reduction in cellulose was accompanied by proportional increases in lignin （35%） and non-cellulosic polysaccharides （55%） compared to the 22% lignin and 36% non-cellulosic polysaccharides in control plants. The transgenic stems pro- duced typical collapsed or ＇irregular＇ xylem vessels that had altered secondary wall morphology and contained greatly reduced amounts of crystalline cellulose. These results demonstrate the fundamental role of secondary wall cellulose within the secondary xylem in maintaining the strength and structural integrity required to establish the vertical growth habit in trees.

Water-Based Processing of Fiberboard of Acrylic Resin Composites Reinforced With Cellulose Wood Pulp and Cellulose Nanofibrils

Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic character.Here we describe fiberboard composites with high contents of wood pulp or cellulose nanofibrils,and a resin of poly(styrene-methyl-methacrylate-acrylic acid)used as water-based emulsion.Cellulose wood pulp and cellulose nanofibrils were used directly in the form of water suspensions.The method is based on the flocculation of the polymer emulsion followed by agglomeration of a mixture of the polymer emulsion and cellulose suspension,leading to the co-precipitation of the composite material,which can be easily separated from the water phase.Composites with acrylic polymer/cellulose fibers in the proportions of 75:25,50:50 and 25:75 wt%were prepared.Composites were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),dynamic mechanical analysis(DMA)and water absorption tests.SEM analysis revealed a very good dispersion of the fibers without evidence of agglomeration,which led to superior mechanical properties.These results showed the effectiveness of the methodology and the potential of cellulose wood pulp and CNF as reinforcement fillers in fiberboard composites and any other high fiber-content materials.

Solubility of wood-cellulose in LiCl/DMAC solvent system

A LiC1/DMAC solvent system was used to dissolve wood-cellulose with aims to broaden its application in preparing functional materials of modified wood-cellulose. We studied the dissolubility complexion of wood-cellulose in a LiC1/DMAC solvent system, made sure of the important function of LiC1 in a cellulose solvent, and further confirmed its dissolution mechanism via the measurement of infrared spectra of soluble products. The study results are as follows： first, LiC1 salts, which can form intermediate complexes with cellulose, have played an important role in the LiC1/DMAC solvent system, and their solubility performance is en- hanced by reducing the hydrogen bond effect between cellulose molecules; second, the non-aqueous solvent system is a better method for dissolving wood-cellulose in homogenous phase. As found in infrared spectra, the absorption intensity of hydroxyl groups （broad peaks： 3,400 cm^-1） decreased greatly in cellulose macromolecules. This is because the degree of association between the hydroxyl groups of cellulose macromolecules is reduced, due to the destruction of the hydrogen bonds. Lastly, wood-cellulose can be dissolved in a LiC1/DMAC solvent thoroughly and efficiently, and can provide a better solvent system for homogeneous synthesis in the preparation of new functional materials via modified wood-cellulose.

Reinforcement of Lignin-Based Phenol-Formaldehyde Adhesive with Nano-Crystalline Cellulose (NCC): Curing Behavior and Bonding Property of Plywood

The curing behavior of lignin-based phenol-formaldehyde (LPF) resin with different contents of nano-crystalline cellulose (NCC) was studied by differential scanning calorimetry (DSC) at different heating rates (5, 10 and 20&degC/min) and the bonding property was evaluated by the wet shear strength and wood failure of two-ply plywood panels after soaking in water (48 hours at room temperature and followed by 1-hour boiling). The test results indicated that the NCC content had little influence on the peak temperature, activation energy and the total heat of reaction of LPF resin at 5 and 10&degC/min. But at 20&degC/min, LPF0.00% (LPF resin without NCC) showed the highest total heat of reaction, while LPF0.25% (LPF resin containing 0.25% NCC content) and LPF0.50% (LPF resin containing 0.50% NCC content) gave the lowest value. The wet shear strength was affected by the NCC content to a certain extent. With regard to the results of one-way analysis of variance, the bonding quality could be improved by NCC and the optimum NCC content ranged from 0.25% to 0.50%. The wood failure was also affected by the NCC content, but the trend with respect to NCC content was not clear.

Synthesis of Microcrystalline Cellulose—Polyvinyl Alcohol Stabilized Polyvinyl Acetate Emulsion

Polyvinyl alcohol (PVA) colloid stabilized Polyvinyl acetate (PVAc) based wood adhesive has poor performance in highly humid conditions. Currently, the addition of natural fillers in the wood adhesive is one of the most effective ways to enhance the performance of PVAc wood adhesive in highly moist conditions. Microcrystalline cellulose (MCC) are strong renewable, bio-based material and has great potential in a reinforcement of the polymeric matrix. Hence, the present work investigates the applicability of microcrystalline cellulose incorporated 3% and 5% in situ emulsion polymerization PVAc wood adhesives. Effect on physical, thermal and mechanical properties was studied by viscosity, pH, contact angle measurement, differential scanning calorimetry (DSC) and pencil hardness test of films. Emulsions with different proportions of MCC were prepared and the shear strength of the applied adhesive on wood was measured. The viscosity of the adhesives was increased by increasing the concentration of MCC. The mechanical properties like tensile strength of adhesives with MCC were measured by universal tensile machine (UTM). Thermal stability was studied by differential scanning calorimetry (DSC). The tensile shear strength demonstrates that MCC can improve bonding strength as compared to PVAc Homo based adhesive in the wet condition which was validated through a contact angle study. The hardness of PVAc films were also changed positively by the addition of MCC. Here, we studied the effect of the addition of different concentrations of MCC materials in situ polymerization of PVAc on their performance properties.

Physicomechanical Properties of Sustainable Wood Plastic Composites of Tropical Sawdust and Thermoplastic Waste for Possible Utilization in the Wood Industry

This work investigated and quantified the physicomechanical properties of flat-pressed wood plastic composites produced with recycled polyethylene terephthalate, recycled polyethylene and sawdust derived from selected tropical timbers, namely, Nauclea diderrichii, Brachystegia eurycoma, Erythrophleum suaveolens and Prosopis africana, for possible utilization in the wood industry. The compounding of the polymer blends of the precursor plastics, namely recycled PET (rPET) and recycled PE (rPE) with the sawdust (SD) from the selected timbers to produce the desired wood rPET/rPE composites was carried out via the flat press method. The characterization of the physicomechanical properties of the wood plastic composites (WPCs) produced, such as the density, hardness, flexural strength, ultimate tensile strength, elongation %, thickness swelling and water absorption capacity was carried out using methods based mainly on the European Committee for Standardization (CEN) and the American Society for Testing Materials (ASTM) standards. The results of the investigation on the resultant composites indicated that changes in the SD content affected the density of flat-pressed WPCs in line with literature. Generally, it was observed that as wood dust increased and PET content decreased, the density of composites decreased with some deviations as expected probably due to the anisotropic nature of the wood fillers. The analysis of variance (ANOVA) revealed that there was a statistically significant variation in the wood composites of Nuclea diderichii based on the physicomechanical values as the p-value (0.020) obtained was less than the critical level of α = 0.05. It was also observed that the composite, Wood 1 Sample 5 (W1S5) which was composed of 40% rPE, 40% rPET and 20% SD (derived from Nuclea diderichii), had the highest percentage elongation (26.84%);the highest flexural strength (14.995 N/mm2) and possibly the least carbon footprint in the environment. These properties of W1S5 suggest that it could therefore be the best option for the production of building materials like ceiling boards or floor skirting in the wood plastic composite industry. The results of these investigations have therefore indicated that the fabrication of WPCs from sawdust and rPET/rPE was technically feasible and had prospects for large scale production in the wood industry.

An Evaluation of the Physicochemical, Structural and Morphological Properties of Selected Tropical Wood Species for Possible Utilization in the Wood Industry

This work investigated and quantified the physicochemical, structural and morphological properties of four (4) tropical timbers as precursor raw materials for possible utilization in the wood plastic industry. The physicochemical properties of the wood samples such as the bulk and tapped density, moisture content, water absorption capacity at 25°C, volatile content, fixed carbon, ash content, alpha cellulose, hemicellulose, lignin, and extractives contents were determined using standard methods like the European Committee for Standardization and (CEN/TS) and the American Society for Testing Materials (ASTM) standards. The structural and morphological properties of the samples were examined with Fourier Infrared Transform (FTIR) spectroscopy and scanning electron microscope (SEM). Results indicated that the bulk density values of the timbers ranged from 0.34 g/cm3 in Brachystegia eurycoma (W3) to 0.47 g/cm3 in Erythrophleum suaveolens (W2), with the other timbers, Nuclea diderichii (W1) and Prosopis africana (W4) having the same bulk density of 0.40 g/cm3. With respect to their moisture content, W2 had the highest value (8.38%) while Nauclea diderrichii had the lowest value (6.52%). The water absorption capacities of the woods studied correlated with the cellulose composition of wood in the order of: W3 > W1 > W4 > W2. The FTIR results showed that W2 and W3 presented a slightly more prominent and broader band than the other woods at 1731 cm-1, in agreement with the higher holocellulose content of these species, while W2 and W4 presented the most prominent peaks indicating higher lignin content than W1 and W3. The SEM micrographs of the wood flour samples investigated indicated that the surfaces of the woods were rough and heterogeneous with irregular crystal and brick shaped particles. A two-way analysis of variance (ANOVA) carried out with respect to the chemical composition of the wood samples indicated that there was no statistically significant variation in the wood chemical composition between species as the p-value (0.852) obtained was greater than the critical level of α = 0.05.

纤维素基环氧树脂及其木材胶粘剂粘接性能研究

以碱活化的纤维素为原料,通过与环氧乙烷(EO)发生接枝液化反应,合成了液体纤维素基环氧树脂(PHECEP)。然后以E-51为基体树脂,胺类T31为固化剂,硅微粉、硅烷偶联剂KH-560和PHECEP为改性剂,制备纤维素基环氧树脂胶粘剂,并对其进行力学性能、热性能和耐化学性等测试。研究结果表明:在PHECEP掺入量为20%时,抗冲击强度从2.9 kJ/m^(2)提升到50.9 kJ/m^(2);当PHECEP掺入量为5%时,室温下固化7 d的纤维素基胶粘剂拉伸剪切强度比纯E-51提高了171.1%。掺入PHECEP后,实际拉伸剪切强度高于测试中的强度,并且在小分子溶剂中耐受性更优良。通过PHECEP/E-51材料的力学性能、干湿粘接强度、热稳定性和耐化学性等性能的综合评判,得到相对最优的木材胶粘剂配方为:5%PHECEP(相对于E-51质量而言),1%的KH-560、60%的硅微粉和18%的T31固化剂(分别相对于PHECEP和E-51总质量而言)。

基于蓝莓花青素的新鲜度指示膜制备及性能研究

为提升pH指示膜的综合性能,以微晶纤维素(micro-crystalline cellulose,MCC)、马铃薯淀粉(potato starch,PS)、聚乙烯醇(polyvinyl alcohol,PVA)为原料,蓝莓花青素(blueberry anthocyanins,BA)为指示剂,采用流延法制备指示膜,对指示膜的性能进行分析。结果表明,当BA、MCC、PS和PVA的质量比为0.3:0.2:3:0.3时,微晶纤维素提高了薄膜的拉伸强度(1.59 MPa至2.16 MPa)、断裂伸长率(35.83%至38.24%)、杨氏模量(8.25 GPa至25.65 GPa),降低了薄膜的含水率(34.85%至33.23%)和吸水率(122.97%至110.36%)。蓝莓花青素提高了薄膜的机械性能、阻隔性能,降低了耐水性,且与膜中各基质融合良好,指示膜结构均匀、致密。拉伸强度和杨氏模量分别升至2.19 MPa和37.12 GPa;透水率、含水率和吸水率分别降至1.45×10^(-12) g·cm/(cm^(2)·s·Pa)、30.7%和87.52%。蓝莓花青素还赋予薄膜pH敏感性。在不同pH环境中,指示膜与花青素的颜色变化趋势一致,色差可视;同时环境稳定性佳,在不同温度和光照条件下,指示膜的颜色稳定超过14 d(ΔE≤2)。研究结果可为蓝莓花青素指示膜的制备提供参考。

木质素优先解聚对碳水化合物影响的研究进展

木质纤维素类生物质是丰富的可再生资源,有潜力替代化石资源来生产清洁燃料和化工产品。将木质纤维素类生物质全组分转化利用,既减少了环境污染,又提高了资源利用率。木质素的优先解聚是实现木质纤维素类生物质全组分高值转化的有效途径之一。本文综述了木质素优先解聚策略对木质素解聚产物及碳水化合物的影响,包括还原催化、氧化催化、碱催化、酸催化、水热、热解等6种不同催化方法的研究进展,以及各个解聚方法的反应机理,并且对不同解聚方法的优缺点进行了分析:还原催化解聚,酚类单体产率高,可以保留绝大部分碳水化合物;氧化催化解聚反应条件温和,可以使用廉价、绿色的氧化剂将木质素转化为低聚物或芳香族单体,并且可以保留高质量的纸浆;碱催化和酸催化常用于预处理阶段使原料进入膨胀状态,并使碳水化合物尤其是半纤维素降解,导致木质素解聚产物难以分离;水热解聚操作简单,反应温和,但在木质素解聚的同时纤维素和半纤维素也会逐渐水解;热解可同时生成木质素衍生的酚类和糖衍生物,但是产物选择性较低,对下游分离存在较大障碍。最后对木质素优先解聚的研究重点和发展方向进行了展望。

Effect of Crystalline Structure of Wood on Liquefaction

By means of X ray and gas chromatography analysis, the crystalline structure of untreated wood , alkali treated wood and benzylated wood and their liquefaction in toluene and tetrahydrofufan with HCl as a catalyst were studied .The upper solution of benzylated wood was also studied by GC MS analysis. It proved that the introduction of bulky benzyl group in wood significantly changed the crystalline structure of wood ,enlarging the free volume which facilitated the penetration of solvent into the matrix of treated wood, thus tremendously enhancing thesolubility in solvent,compared to untreated wood and alkali treated wood. The percentage of residue decreased and the combined solvent increased with the increase of weight gain revealed that the liquefaction process became easy. Furthermore, the factors that influenced the liquefaction of benzylated wood were investigated. It showed that the liquefaction performance was improved with the increase of liquefaction time and the amount of catalyst when toluene was used as a solvent, especially in the presence of THF as solvent, there existed the optimum liquefaction time and the amount of catalyst .

微晶纤维素在季铵碱水溶液中的低温溶解研究

选用四甲基氢氧化铵(TMAH)、四乙基氢氧化铵(TEAH)、四丙基氢氧化铵(TPAH)3种季铵碱水溶液为溶剂,通过低温冷冻、室温解冻溶解微晶纤维素(MCC),研究不同温度及不同溶剂浓度下MCC的溶解效果,对不同季铵碱水溶液处理后的MCC的溶解行为进行表征。结果表明:随着冻融温度的降低,3种溶剂中MCC的溶解度整体上均呈现先上升后慢慢趋于稳定的趋势;在不同溶剂体系下,随着季铵碱浓度的增大,MCC的溶解度均呈现上升趋势;当冻融温度为-30℃、溶剂中季铵碱质量分数为35%时MCC的溶解效果最佳,在TMAH、TEAH和TPAH水溶液中MCC的溶解度分别为1.2%、11.5%和7.25%;季铵碱水溶液体系为MCC的非衍生化溶剂体系,其中TEAH能够削弱MCC内部氢键,溶解能力最强;经TEAH、TPAH处理的MCC的结晶度均下降,其中TEAH溶胀处理后MCC的结晶度由63.11%下降到43.71%,TEAH溶解后再生MCC的结晶度下降到30.46%,MCC的晶型由纤维素I晶型转变为纤维素II晶型;3种季铵碱水溶液中TEAH去结晶能力最强,对MCC的溶解效果最好。

不同结晶度纤维素与1-丁基-3-甲基咪唑氯混合热解特性研究

通过等体积浸湿的方法对不同结晶度的纤维素负载1-丁基-3-甲基咪唑氯([Bmim]Cl)离子液体,获得了负载离子液体的纤维素和再生纤维素样品,在固定床反应器上探究了不同结晶度纤维素负载离子液体的热解行为,并分别对其三态产物生物焦、生物油、生物气进行了分析。结果表明:纤维素再生过程会破坏内部晶体结构,使其无定形区域变大,脱水反应更加容易发生;热解温度为275℃时,与纤维素相比,结晶度更低的再生纤维素能够促进挥发物的生成以及抑制固体碳的生成,液体产率及固体产率分别从48.23%、48.81%变化至55.7%、37.67%,而热解温度在300~350℃的高温下却相反;负载离子液体后可以促进LGO等物质的生成,最高产率可达到16.1%,高结晶度能够促进离子液体对LGO的催化作用。

Phosphoric Acid Pretreatment and Saccharification of Paper Sludge as a Renewable Material for Cellulosic Fibers

Recycling of paper sludge waste is crucial for establishing a sustainable green industry.This waste contains valuable sugars that can be converted into important chemicals such as ethanol,poly hydroxybutyrate,and lactic acid.However,the main challenge in obtaining sugars in high yield from paper sludge is the high crystallinity of cellulose,which hinders hydrolysis.To address this,pretreatment using phosphoric acid was optimized using response surface methodology to facilitate cellulose hydrolysis with minimal energy and chemicals.The created prediction model using the response surface method considered factors such as acid concentration(ranging from 60%to 85%),consistency(ranging from 4%to 10%),temperature(ranging from 25℃to 80℃),and time(ranging from 0.5 to 4 h).The results revealed that the model’s significant factors affecting the yield were acid concentration,reaction time,temperature,and the product of acid concentration and temperature,while the model’s significant factors affecting the crystallinity were the consistency,the temperature,and their product.The results showed that the optimum conditions for pretreatment were using an acid concentration of 64%,temperature of 25℃,consistency of 10%,and time of 30 min.The hydrolysis of the conditionally pretreated paper sludge resulted in a weight loss of 42%,compared to only 18%weight loss in non-pretreated paper sludge.Furthermore,the optimized conditions led to low levels of furfurals and acetic acid,which are undesirable by-products that can interfere with sugar fermentation.The total sugar obtained under the optimized conditions was 0.43 g glucose/g sample(10.46 g/L),while the contents of methyl furfural,furfural,and acetic acid were 21.65,235.7,and 4.57 mg/L,respectively.This study demonstrates the potential of phosphoric acid for pretreatment and hydrolysis of paper sludge,enabling efficient saccharification and the production of sugars with minimal undesired by-products.

绿色纤维素基水凝胶膜的制备及油水分离性能

以杨木粉(PF)中提取的纤维素木浆(PF-NA)为基底,通过冷冻盐析技术,利用聚乙烯醇(PVA)将LiCl颗粒包裹在纤维素骨架上制备了纤维素基(CLH)水凝胶膜。采用FTIR、SEM、XRD、XPS对CLH水凝胶膜进行了表征,对其机械、高温、耐酸碱和耐盐稳定性、自清洁和耐污性进行了测试。结果表明,CLH水凝胶膜具有三维层状结构,PVA的加入及冷冻盐析技术的利用提高了CLH水凝胶膜的力学性能。LiCl作为吸水单元分布在纤维素骨架周围,使CLH水凝胶膜具有超亲水性,水下油接触角为151°;在重力作用下,CLH水凝胶膜可以实现对油水混合物和水包油乳液的高效分离,在高温(60℃)、强酸(pH=3)和强碱(pH=13)条件下具有稳定的分离效率(≥99.8%);在循环分离12次水包机油乳液中,CLH水凝胶膜保持稳定的分离性能;CLH水凝胶膜对四氯乙烯油渍具有自清洁和耐污能力。

Cellulose Nanocrystal from Washingtonia Fibre and Its Characterization

Cellulose nanocrystal(CNC)is a biomaterial derived from plant lignocellulosic components,widely applied in various industrial fields.Concurrently,with the growth of awareness in developing green nanomaterial,the explored Washingtonia fibre could be alternative biomass for obtaining CNC products.In the present work,different acid concentrations of 5%,15%,and 25%hydrochloric solutions were employed to produce CNCs from Washingtonia fibre.With the chemical treatments,the yield of the CNC product was successfully retained at 21.6%-25.1%.Individually separated and needle-shaped CNC particles could be observed under the microscopic viewing with the increased acid concentrations.From elemental analysis,a relatively pure cellulose compartment was produced for all CNC samples.The zeta potential values between-10 to-16 mV proved that each nanoparticle sample possessed dispersion ability within an aqueous solution.Meanwhile,the degree of crystallinity and the thermal behavior of CNCs were enhanced with the increased acidic concentrations.Hence,the isolated CNCs(with 15%)from Washingtonia fibre lead a CNC with the highest aspect ratio(30).This parameter is so important that these structures show empowering points of view as nanomaterials for reinforced polymer composites,and it could be a reliable nano-filler for the composite fabrication process in the future.

水洗对稀酸蒸汽爆破玉米秸秆酶水解的影响

蒸汽爆破是木质纤维素综合利用的常用预处理方法,但常会产生一些抑制物抑制酶水解。以蒸汽爆破玉米秸秆为研究对象,探究水洗处理对木质纤维素酶水解的影响。发现水洗后蒸汽爆破玉米秸秆酶水解的效率提升超过18%,远高于其他碱处理脱毒手段。通过分析底物亲和力、酶活力和形态观察等,解析水洗促进蒸汽爆破玉米秸秆酶水解的机制。结果发现,经过水洗后的蒸汽爆破玉米秸秆的底物与酶亲和力提高了18.8%(Km值从7.84降低至6.60)、内切酶与外切酶活力显著提高,纤维素形态均发生了利于酶水解的改变。