Green and Effective Ammonium Carbonate-assisted Process for Drying Hemicellulose Obtained through Alkali Extraction of Bleached Bamboo Kraft Pulp

Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually present as a spent liquor,such as the prehydrolysis liquor of the prehydrolysis kraft dissolving pulp production process and the alkali extraction liquor of the cold caustic extraction of pulp fibers.Due to its dilute nature,hemicellulose needs to be dried for practical utilization,and this is challenging.In this study,cellulose and hemicellulose in a bleached bamboo kraft pulp were separated using an alkali extraction process.Hemicellulose obtained from the extraction liquor was dried by an ammonium carbonate-assisted drying process.The effects of drying time and drying temperature were determined.Structure of the hemicellulose obtained by the ammonium carbonate-assisted drying process was similar to that of original hemicellulose,as revealed by detailed Fourier transform infrared and X-ray diffraction analyses.The novel drying method was more energy efficient and required a shorter drying time than the conventional freeze drying method,and the excellent solubility in alkaline solutions favored the chemical modification of hemicellulose.The dried hemicellulose can be used as a renewable raw material for the preparation of hydrogels and other substances such as bioethanol/biochemicals and biodegradable films.

Characterization of Structure and Property of the Monocarboxyl Bamboo Pulp Fibers

The oxidized bamboo pulp fiber yarns were prepared by the HNO3?/H3PO4-NaNO2 oxidation system. The effects of the oxidation concentration and reaction time on the weight loss, the carboxyl content and the breaking strength of the bamboo pulp fiber yarns were studied and the aggregation structure was investigated by Fourier transform infrared, X-ray and scanning electron microscopy. The results revealed an increase in carboxyl content and a decrease in breaking strength of oxidized bamboo pulp fiber yarns with increasing concentration of oxidant and reaction time. The breaking strength of oxidized bamboo fiber yarns was damaged seriously once the reaction time was more than 120 min or the concentration of oxidant was greater than 1.0%. The crystallinity of bamboo pulp fibers increased slightly under low oxidation degree but decreased with higher oxidation degree.

Wearability of Copper Ion Complex Bamboo Pulp Knitted Fabrics with Chitosan Pretreatment

Wearability is one of important factors for the textile product quality. The wearability of bamboo pulp knitted fabrics was mainly discussed which were treated with chitosan and cupper ammonia solution. Tensile and bursting properties, abrasion resistance,drapability,air permeability,moisture-penetrability and warmth retention properties of fabrics were tested to investigate the changes. The results showed that chitosan pretreatment improved the tensile and bursting strengths,abrasion resistance and moisture penetrability,but decreased the drapability and air permeability.Copper ammonia solution treatments decreased the tensile and bursting strengths,abrasion resistance and air permeability,but increased the drapability, moisture penetrability and warmth retention properties.

Effect of Acetic Acid Prehydrolysis on Unbleached Bamboo Pulp Production

Bamboo was used as raw material for unbleached pulp production.An acetic acid prehydrolysis process was employed before the pulping process.The effect of acetic acid prehydrolysis on pulp properties was investigated.The results showed that some components,such as hemicellulose and extractives,were degraded or dissolved in the prehydrolysis process prior to kraft pulping.SEM images of the substrate after treatment indicated that the parenchyma cell wall was thinner,and the size of pores between fiber bundle cell walls was larger.The pulping results showed that acetic acid prehydrolysis could improve the pulp quality and make the pulp easier to bleach.The brightness of the pulp reached 59.6%ISO with a single oxygen delignification step.The acetic acid prehydrolysis decreased pulp viscosity and fiber length,but not significantly.The amount of parenchyma cells in the pulp was reduced,which was beneficial for papermaking and improving mechanical strength of paper.This procedure has good potential for unbleached pulp production.

Mechanical and Rheological Properties of Bamboo Pulp Fiber Reinforced High Density Polyethylene Composites:Influence of Nano CaCO_(3)Treatment and Manufacturing Process with Different Pressure Ratings

In order to investigate the effect of the relative motion of nano CaCO_(3)reinforced bamboo pulp fiber(BPF)/HDPE composite components on the mechanical performance,a comparative study was performed.BPF was treated by nano CaCO_(3)blending(BM)and impregnation modification(IM)technology.The composites were produced using hot press(HPMP),extrusion(EMP)and injection molding process(IMP).The physical morphology of BPF was similar at different manufacturing processes.Compared to the samples manufactured by HPMP,a decrease in the(specific)flexural strength of BPF/HDPE composites and an increase in those of composites treated by nano CaCO_(3)manufactured by EMP and IMP were observed.The injection molded composites exhibited the best values in the(specific)impact strength,(specific)tensile properties.IM had a greater effect on the rheological behavior of the composites than BM,and nano CaCO_(3)treatment most effectively affected the performance of the extrusion molded composites.

Bamboo Plantations to Augment Pulp Production

由于作为纸浆工业的原材料 ,因此竹子在非木质林产品中占有重要的位置。然而 ,过量采伐和人口增长 ,热带林的破坏以及工业原料的新需求 ,尤其是纸浆工业 ,导致竹子资源大量减少 ,目前面临锐减的形势。国家农业委员会发表的数字表明 ,1980和 2 0 0 0年的需求与产出为 4 2 5 .0万t和 875 .0万t,需求与供给之间出现增长的差距。可以看出 ,只有通过人工林增长的方法和有效地利用现有的资源才能达到可持续性。

Effects of Ultrasonic Treatment on Kraft Pulping of Bamboo

By applying ultrasound at different stage of kraft pulping process, the properties of kraft pulp produced by ultrasonic treatment were studied and compared with those by conventional method. The results indicated that, while the performances of the pulp were close to conventional kraft pulp, the chemical-to-wood ratio decreased from 20% to 17.5%, cooking time was shortened from 140 to 120 rain, and the yield increased. When the ultrasound came into play at the 90th minute during pulping process, the properties of the produced bamboo fiber were the most desirable.

Effects of supercritical ammonia on bamboo pulping

We investigated the effects of supercritical ammonia on pulping of bamboo in a preliminary study,using testers such as differential scanning calorimetry（DSC）,scanning electron microscopy（SEM）,X-ray diffraction（XRD） and energy dispersive spectroscopy（EDS）.The results indicate that under supercritical conditions at 185-190°C,it is possible for the ammonia to realize bamboo pulping.Compared with conventional kraft pulping,the products can meet the quality requirements of industrial paper.

REFINING BEHAVIOUR OF BAMBOO LONG FIBRE FRACTION PULP

Refining of pulp significantly contributes to papermaking process by affecting the runnability of the stock and quality of end product. The greater the production rates of a paper, the greater are the effects of machine downtime through breaks. A correct approach towards refining treatment is very essential for energy savings and product with desired properties. Papermakers are being encouraged to use non-wood fibres for a variety of reasons - the environment, changing agricultural policy and long-term fibre supply. Compared with wood fibres, there is less knowledge on how to treat non-wood fibres for optimum performance. Laboratory studies aimed at understanding the behaviour of unbleached bamboo long fibre fraction pulp on refining in Escher Wyss Laborefiner under simulated process conditions included investigations of the important parameters like wet web tensile, wet web elongation, water retention value and paper strength properties. The paper describes the influence of two specific edge loads, 1000 and 1500 Ws/km on refining of pulp. Bamboo long fibre fraction pulp responds better to lower intensity refining to develop pulp strength.

STUDY ON THE ELEMENTAL CHLORINE FREE BLEACHING OF BAMBOO KRAFT PULP

The influential factors of DQP bleaching, chlorine dioxide bleaching, chelation and hydrogen peroxide bleaching, of bamboo kraft pulp were studied. The pH value in D stage, dosage of EDTA in Q stage and charge of MgSO4 in P stage were optimized. The results indicated that good results of chlorine dioxide bleaching were obtained under the conditions of ClO2 2.0%,pH 4, and the highest final brightness(86.4%ISO) and the lowest final Kappa number(1.37) were attained when the charge of EDTA in Q stage was 0.4%, charge of MgSO4 in P stage was 0.2%, and the other conditions of P stage : pulp consistency 10%, H2O2 charge 2.5%, NaOH charge 1.4%, temperature 90℃ and time 120 min. A comparison of bleaching results, pulp strength and effluent characteristics of bamboo kraft pulp between DQP and CEH sequences was done. The results indicated that bamboo kraft pulp could be bleached to brightness of above 83%ISO by both DQP and CEH sequences. Compared with CEH bleached pulp, DQP bleached pulp had slightly lower brightness, better brightness stability, higher pulp viscosity, better strength properties and lower pollution loads.

喷气涡流纺长片段竹节段彩纱的设计与生产

探讨有色超短纤维在喷气涡流纺花式纱开发中的应用及生产要点。采用有色粘胶超短纤维与本色竹浆纤维、椰炭改性涤纶纤维,在并条机上加装竹节装置,利用喷气涡流纺纱技术纺制成长片段竹节段彩纱。针对粘胶纤维长度相对较短的特点,工艺上尝试采用短流程、减小隔距、降低打击件速度等技术措施。结果表明:开发的喷气涡流纺段彩纱具有段彩片段长、生产效率高的特点,其在布面上色点朦胧,时而形成连续分布,时而散点分布,形成不同于传统段彩纱的独特风格。

纸浆竹林研究现状与发展趋势

本文系统分析了我国纸浆用竹发展概况、竹材造纸特性、竹材制浆技术现状、发展机遇与挑战等方面的问题,并就竹材发展潜力和趋势提出了观点,以探索绿色、低碳、环保、完善、合理的竹浆纸高质量发展路径。

竹浆纸一体化关键技术的突破与展望

本文系统分析了我国竹浆纸一体化进程中竹种质资源筛选与高效培育,多元化浆纸产品生产及过程废弃物高值化利用等方面的关键技术问题,总结了各级政府、科技部门“十四五”期间对技术突破的投入与支持,展望了关键技术落地的预期成效,以期为竹浆纸一体化的高效实施提供重要参考。

预水解硫酸盐竹浆的漂白工艺研究

本研究以预水解硫酸盐未漂竹浆为原料,采用“氧脱木质素(O)-氯漂(D0)-氧和过氧化氢强化碱抽提(Eop)-氯漂(D_(1))”的漂白工艺制备可用作溶解浆的竹浆。通过优化各工段的处理条件(氧漂白段:氢氧化钠用量2.0%、氧压0.5 MPa、反应时间60 min、反应温度95℃;D0漂白段:二氧化氯用量3.5%、反应时间80 min、反应温度70℃、初始pH值4.0;Eop漂白段:过氧化氢用量1.4%、氧压0.2 MPa、反应时间90 min、反应温度90℃、初始pH值11.5;D1漂白段:二氧化氯用量1.5%、反应时间150 min、反应温度70℃、初始pH值4.0),最终制备白度82.7%、黏度440.0 mL/g、灰分含量0.24%、α-纤维素含量90.92%的竹浆。

竹浆与油樟渣浆配抄瓦楞原纸及强度性能研究

本研究对市售本色竹浆进行筛分,利用筛分出的粒径<0.6 mm的短小纤维竹浆与蒸油后的油樟渣浆配抄瓦楞原纸。结果表明,抄纸中加入25%针叶木浆、0.5%阳离子淀粉(CS)、0.4%阳离子聚丙烯酰氨(CPAM)和1.8%聚酰胺环氧氯丙烷树脂(PAE,质量分数9.5%),短小纤维竹浆(未打浆)与油樟渣浆按质量比10∶90配抄,未经熟化处理的纸张裂断长2.66 km,环压指数5.60 N·m/g,达到了瓦楞原纸GB/T 13023—2008合格品要求;当短小纤维竹浆打浆度35.8°SR时,与油樟渣浆按照质量比30∶70配抄,并经110℃、15 min熟化处理,纸张裂断长4.75 km、环压指数8.24 N·m/g、耐破指数2.80 kPa·m^(2)/g、耐折度15次,其中裂断长和环压指数均达到瓦楞原纸GB/T 13023—2008优等品要求,耐破指数和耐折度指标均达箱纸板GB/T 13024—2016合格品要求。

杂细胞对Lyocell级竹溶解浆溶解性能及可纺性能的研究

本研究以自制楠竹溶解浆为研究对象,探讨了杂细胞对楠竹溶解浆的纤维形态、溶解浆性能、溶解性能和可纺性能的影响。结果表明,未筛除杂细胞的楠竹溶解浆,其抗碱性(R_(10)和R_(18))以及聚戊糖和抽出物含量技术指标均优于市售进口溶解浆,但在NMMO水溶液中的溶解性能和纤维溶解状态较差;筛除杂细胞后的楠竹溶解浆,其溶解浆的各项纯度指标均得到有效提升,溶解性能和可纺性能得到明显改善。

纤维素结晶度对纸张静电感应性能影响的研究

纤维素的晶体结构、结晶度对纤维材料介电性能有很大影响,直接影响纤维素材料静电感应性能。本研究以竹浆纤维为原材料,通过不同的热压条件控制纤维素结晶度,利用XRD、FTIR、静电计等手段,对循环处理后纤维素的结晶度、分子结构变化、电学性能等进行分析,探究纤维素结晶度与纸张抗张指数、纤维电学性能之间的关系。结果表明,竹浆纤维纸张的抗张指数随其结晶度的升高略有降低,而静电感应性能有上升趋势。

不同性能麻竹浆制备空气滤纸的研究

本研究以不同竹龄的麻竹为原料,通过硫酸盐法蒸煮成浆,探讨了竹龄对竹浆纤维形态、竹浆纸物理性能及过滤性能的影响。结果表明,随着竹龄的增加,竹浆纤维的长度、宽度及长宽比等均有不同程度的增加。竹浆纸物理性能随着竹龄的增加呈现不同的变化规律,其中松厚度、孔径及透气度均随竹龄的增加呈逐渐增加的趋势,当竹龄为36月时,竹浆纸松厚度为5.35 cm^(3)/g,平均孔径为29.1µm,透气度为774 mm/s;竹浆纸挺度随竹龄的增加呈不断下降的趋势,6月竹浆纸挺度达289 mN,约为36月竹浆纸的2倍。竹浆纸的过滤性能品质因子随竹龄的增加呈不断增加的趋势,竹龄36月竹浆纸品质因子可达4.96,优于闪急干燥阔叶浆纸,与闪急干燥针叶浆纸相近。

四种竹材制浆性能及其在过滤基材中的应用研究

本研究以细叶龙竹、大叶龙竹、吊丝竹和甜竹4种3年生竹材为研究对象,对其微观结构、纤维形态、化学组分、纸浆及纸张性能进行了表征,以评估其在过滤基材中的应用潜力。结果表明,4种竹材平均纤维长度均在2 mm以上;综纤维素、木质素和灰分含量分别为65%~73%、18%~26%和1%~3%;经硫酸盐蒸煮的纸浆细浆得率为30%~41%。竹浆滤材与针叶木闪急干燥浆滤材相比,竹浆滤材具有更高的松厚度和挺度,基于纸张松厚度、孔径、透气度、过滤效率、过滤阻力及品质因子评价,甜竹浆滤材过滤性能较好,品质因子达5.66,优于针叶木闪急干燥商品浆滤材。

麻竹纤维制备铝电解电容器隔膜性能研究

本研究在低紧度下,以麻竹浆和剑麻浆为原料,经相同的过程处理后,通过PFI磨浆处理,采用PTI湿法成形制备单层铝电解电容器隔膜,探讨麻竹浆作为电解电容器隔膜原料的可行性。对浆料制备的电解电容器隔膜孔径结构、吸水性能、绝缘性能进行测试。结果表明,打浆度20、65°SR的麻竹隔膜平均孔径分别为24.88、1.11μm,Cobb吸水值分别为26.89、35.59 g/m^(2),交流击穿强度分别为59.12、97.98 kV/cm。打浆度20和65°SR的剑麻隔膜平均孔径分别为26.67、7.12μm,Cobb吸水值分别为21.25、33.24 g/m^(2),交流击穿强度分别为50.68、92.21 kV/cm。麻竹隔膜的表面吸水能力、击穿强度大于剑麻隔膜,同时其孔径小于剑麻隔膜,说明麻竹浆可以做铝电解电容器隔膜原料。