Characterization and acetylation behavior of bamboo pulp

In the present study, the chemical–physical properties of bamboo pulp prepared with a sequential totally chlorine-free procedure were analyzed and compared with that of commercial wood pulp by SEM, FTIR, TGA, and X-ray. α-Cellulose content was determined to be 95%, a little less than that of commercial wood pulp. But the crystallinity of bamboo pulp is lower than wood pulp. Acetylation activity of bamboo pulp was determined to be higher than that of wood pulp, which was carried out in heterogeneous media with sulfuric acid as catalyst. The cellulose acetate prepared with bamboo pulp can be quickly dissolved in acetone without distinct difference with that of cellulose acetate prepared with wood pulp. The results indicate the potential utility of bamboo as an alternative to wood pulp for cellulose derivate fiber material.     

重组竹制造工艺的研究

本文是作者在施胶量、热压温度和热压时间三个主要因子对重组竹性能影响的初步研究基础上又进一步探讨了施胶方式、竹纤维束水洗、胶种以及胶的浓度等因素对产品性能的作用。研究结果表明:竹纤维束水洗有较显著的作用;水溶性酚醛胶比醇溶性酚醛胶更适用于重组竹的制造,胶液浓度过稀不仅自身性能差,而且还会使重组竹性能降低;采用浸胶方法虽有利于胶液的均勻分布,但对IB未产生明显的作用。     

Adsorption behavior of aluminum compounds on pulp fibers at wet-end

Various aluminum compounds were added to pulp suspensions, and the adsorption behavior of their aluminum components on pulp fibers was studied. Aluminum contents in the handsheets were determined using an energy dispersive X-ray analyzer attached to a scanning electron microscope and an X-ray fluorescence analyzer. Although aluminum contents in the handsheets increased with increasing additions of the aluminum compounds, the detailed adsorption patterns varied among the aluminum compounds used. Their chemical structures and the pH values of the pulp suspensions greatly influence the adsorption behavior. When fines are present in the pulp suspensions, the aluminum components are predominantly adsorbed on the fines, probably due to their larger surface areas or the higher carboxyl contents compared to those of coarse fibers. Not only aluminum flocs but also far smaller components such as various aluminum cations seemed to be adsorbed on pulp fibers. Most aluminum flocs, which are formed in pulp suspensions by reacting with OH and entrapped in a fiber matrix by filtration effects, are removable by repeated mechanical agitation of the pulp suspensions.     

热处理工艺对竹材蠕变性能的影响

采用不同热处理温度和时间对6年生毛竹进行改性处理,并分析其蠕变特性的变化规律。结果表明:当热处理温度为140℃时,蠕变柔量随热处理时间的增加而减少;热处理温度为220℃时,蠕变柔量随热处理时间的增加而增加;热处理温度180℃的竹材恒定蠕变阶段的蠕变速率大于140℃时的蠕变速率,蠕变柔量由低温时随热处理时间增加而降低,向高温时随热处理时间增加而增加转变过渡。热处理时间为2和4 h时,其蠕变柔量随热处理温度升高而降低,减速蠕变阶段变化较为接近;而热处理时间为6 h时,其塑性随热处理温度的升高而增大,蠕变柔量也随之增大。     

竹材中密度纤维板（MDF）防霉研究

用厘竹、青皮竹、篙竹制成的MDF为试材,以国产TMO、DD及比利时的MECT三种防霉剂对其进行处理后,从板的物理力学性能及抗霉效力等方面进行比较表明,对木材有效的防霉剂并非对竹材MDF也有效。MECT与TMO比较,前者抗霉效力略高于后者,但前者使板的强度下降幅度较大,而价格约为后者的5倍。如果用法得当,TMO对竹材MDF的抗霉效力仍可达到100%。工艺试验结果表明,合适的制板工艺将使板的抗霉效果得到充分发挥,而且可以保证板的物理力学指标处于高水平前提下,确定其最低的原料及防霉剂消耗水平。     

壳聚糖对竹溶解浆溶液流变性能的影响

采用浓度为84.2%的N-甲基吗啉-N-氧化物(NMMO)水溶液为溶剂,设计竹溶解浆(BP)-壳聚糖(CS)不同质量分数,依次加入CS粉末和BP,BP充分溶解后制备BP与CS不同质量比的共混溶液。研究了CS对NMMO溶解BP溶液的稳态和动态流变性能。研究表明:在NMMO溶解体系中,BP-CS共混溶液为剪切稀化的假塑性流体,在持续摇振过程中,随着溶液温度(θ)升高,溶液的储能模量(G′)和损耗模量(G″)、复数黏度(η*)均下降,加入适量的CS(CS∶BP=1∶10)可有效阻碍BP大分子不同链间即时物理交联位点的形成,从而改善NMMO溶解BP溶液的流变性能,但是,随着CS添加量的增大,CS与BP大分子链间的相互作用增加又导致了溶液的流变性能降低。     

丛生竹纸浆林调控出笋技术

在四川泸州和宜宾选择梁山慈竹、撑绿竹、硬头黄竹纸浆林开展笋目位置和年龄的调控出笋试验,分析出笋率、成竹率、新竹相对生长率和竹材产量后得出:(1)合理的"抹目"、"疏芽"可以提高成竹率、增加新竹相对生长率和竹材产量,梁山慈竹、撑绿竹、硬头黄竹在同时抹除3目、4目时效果最好,从不抹目到抹除3目、4目的增产幅度分别达31.04%、25.59%和37.87%;(2)在保证笋目出笋成竹能力和养分供给下,母竹数的减少和年龄结构的调小不会减小丛生竹纸浆林产量,梁山慈竹和硬头黄竹在保留所有1年生母竹和25%的2年生母竹,撑绿竹在保留所有1年生母竹和50%的2年生母竹时产量最高.综合分析认为:对笋目位置和年龄的调控出笋技术可为丛生竹纸浆林生产经营提供新的经营思路.     

竹材防霉剂筛选试验

本试验以毛竹为试材,对九种防霉剂进行筛选试验,筛选出四种高效低浓度防霉剂,它们是:75号工业防霉剂、DP防霉剂、硼酚合剂与氟酚合剂。防霉效果稍次的有三种:甲基托布津、多菌灵、福美双、使用浓度稍高于1%。防霉效果欠佳的有杜香油与新洁尔灭硼化合剂。     

竹材开发利用研究综述

中国是竹业资源大国,以竹代木,是解决国内目前木材供应缺口的最佳途径.文章较全面地介绍竹材的开发利用,竹材人造板的开发,竹炭和竹醋液的机能、用途等。     

竹地板薄木贴面工艺试验

为了丰富竹地板的外观效果,扩大竹地板的种类,采用正交试验方法,探讨了竹地板表面进行0.6 mm榉木和2.0 mm枫木薄木贴面工艺。结果表明:利用榉木和枫木薄木贴面竹地板切实可行,其较佳工艺参数分别为:榉木热压压力0.8 MPa,热压温度100℃,热压时间240 s,涂胶量为120 g/m2;枫木热压压力1.2 MPa,热压温度120℃,热压时间360 s,涂胶量140 g/m2。     

蒸汽爆破处理对竹纤维的影响

以小径级毛竹为研究对象,研究了蒸汽爆破处理对制备竹纤维的影响.利用傅里叶红外光谱和扫描电镜对爆破处理前后竹纤维化学成分和纤维形态进行分析.结果表明:蒸汽爆破对竹纤维分离效果好,纤维直径减小,保压时间越长,纤维分散效果越好,柔软性越好.爆破处理能够有效促进纤维中半纤维素降解和木质素的分离,使溶出物颗粒覆盖在纤维表面.蒸汽爆破处理使得竹纤维比表面积增大,改善了竹纤维的形态结构.     

Distribution of methyl-esterified galacturonan in chemical and mechanical pulp fibers

The effects of chemithermomechanical pulping (CTMP), high-temperature (HT)-CTMP pulping, and kraft pulping on the distribution of the pectin polymer, methyl-esterified polygalacturonan have been qualitatively evaluated using immunocytochemistry. Pectin was immunolocalized using an antibody (JIM7) specific for partly methyl-esterified polygalacturonan. A fluorescent antibody was linked to JIM7 and analyzed by epifluorescence microscopy. Pectin was found in both chemithermomechanical pulps in similar uneven patterns: Some fibers showed no labeling, whereas others showed extensive labeling in patches restricted to the fiber surfaces. Pectin labeling of bleached and unbleached kraft pulps did not show any presence of pectin. Labeling was correlated to the presence of compound middle lamella tissue left on the CTMP-treated surfaces. Pectin on pulp-fiber surfaces may affect the interfiber bonds and thereby the pulp properties.     

The influence of the ethanol pumping of wheat straw and of the beating of pulp on the resulting paper sheets

This paper reports on the influence of independent variables in the pulping of wheat straw (viz. cooking temperature and time, and ethanol concentration), and of the number of PFI beating revolutions to which the pulp is subjected, on the yield and Shopper-Riegler index of the pulp, and on the breaking length, stretch, burst index and tear index of the resulting paper sheets. By using a central composite factor design and the BMDP software suite, equations that relate each dependent variable to the different independent variables were obtained that reproduce the experimental results for the dependent variables with errors less than 25% at temperatures, times, ethanol concentrations and numbers of PFI beating revolutions in the ranges 140–180°C, 60–120 min, 40–80% and 0–1750, respectively. Ensuring the optimal Shopper-Riegler index for the pulp (73.18°SR), and also the optimal breaking length (6276 m), stretch (2.57%) and burst index (3.72 kN/g) for the papers sheets, entails using a high temperature (180°C), a large number of PFI beating revolutions (1750) and medium-to-high ethanol concentration and time values; these conditions, however, decrease the tear index for the paper sheets below the optimum level (4.60 mNm²/g). A high temperature and a large number of PFI beating revolutions, in conjunction with a low ethanol concentration (60%) and a short time (60 min), can be used to save solvent and increase the production; the values thus obtained for the dependent variables differ by less than 30% from their optimum levels in the worst case.     

竹木复合定向刨花板强度性能研究

本文论述了竹材、意大利杨复合定向刨花板的强度性能,就胶种、刨花厚度、竹材所占比率、板密度、板坯结构、施胶量等诸因子对板材强度性能的影响进行了探讨。结果表明:(1)胶种对竹木复合定向刨花板的强度影响不大;(2)降低刨花厚度或提高板密度均可使板材强度提高;(3)单层结构的复合定向刨花板强度最高;(4)提高板材中竹材的比率可使板子强度明显改善;但竹材比率过高时,板材强重比反而下降,呈开口向下的抛物线型变化;(5)酚醛树脂定向刨花板的强度随原料酸性增大而降低。     

野生龙竹笋真空软包装加工工艺的研究

本文对云南特有的野生龙竹竹笋为加工原料,根据其特性,以保持野生龙竹竹笋风味,营养及色泽为原则,脱除了其苦涩味,防止了白色沉淀的析出,确定了采用常压杀菌进行竹笋软包装加工的工艺路线。其主要工艺参数是:在100℃条件下蒸煮30min,流水漂洗4h,装袋复煮15min,在真空度0.08~0.09 Mpa下抽真空,100℃杀菌90min,再经冷却、恒温检验、包装即可得到真空软包装野龙竹笋,所制成品达到长期保存的效果。     

竹炭及竹醋液的分析研究

介绍了实验室制取竹炭的一般方法及竹炭和其副产品———竹醋液的实验室分离精制、组分分析方法及理化性质,以及在分离精制过程中各个因素对精制液成分的影响。     

Effect of alkali treatment on wettability and thermal stability of individual bamboo fibers

The aim of this study is to examine the wettability and thermal properties of individual bamboo fibers after alkali treatment. The individual bamboo fibers were treated by sodium hydroxide (NaOH) solution with varying concentrations (6, 8, 10, 15 and 25%) followed by freeze-drying treatment. The surface analysis of alkali-treated individual bamboo fibers was characterized by atomic force microscope. Water droplet on the individual fiber surface was observed with drop shaper analyzer and the contact angles on fiber surface were also measured. Thermal properties were further studied by thermogravimetric analysis. The results indicated that alkali treatment resulted in the increase in surface roughness of individual bamboo fibers. Alkali treatment with low NaOH concentration could enhance the wettability of treated individual bamboo fibers, and while the wettability was reduced with alkali treatment at high concentration (25%). Thermal analysis revealed that the onset of decomposition and the maximum decomposition were moved to higher temperature after alkali treatment at low NaOH concentrations (6, 8, and 10%), suggesting the improvement in the thermal stability of treated individual bamboo fibers, while the thermal stability was compromised after alkali treatment at higher concentrations (15 and 25%).     

Antibody-based assay for galacturonan deesterification on wood pulp fibers during bleaching

Antibodies recognizing galacturonan were used in immunoassays for industrial unbleached and hydrogen peroxide-bleached chemithermomechanical pulp (CTMP). The assays were based on a colorimetric method using specific monoclonal antibody recognition of acidic and methylated homogalacturonan, respectively, on the pulp fiber surfaces. Alkaline phosphatase-conjugated antibodies were linked to the galacturonan specific antibodies, and an alkaline phosphatase substrate (p-nitrophenylphosphate) was used to develop a yellow reaction product that can be followed spectrophotometrically. Together the newly developed immunoassays were able to describe the deesterification, specifically, of surface-localized galacturonan on CTMP, induced by alkaline hydrogen peroxide bleaching. Unbleached CTMP showed relatively more labeling by methylated galacturonan recognizing antibodies, whereas bleached CTMP was relatively more labeled for acidic galacturonan. The increase in negative charge of the bleached pulp was also shown by polyelectrolyte titration; the negative surface charge was 9.3 μeq g⁻¹ in unbleached CTMP and 21.7 μeq g⁻¹ in bleached pulp.     

自承重活动竹地板的研制

本文介绍了一种由中小径级竹子生产的新型竹地板，讨论了生产技术的要点。这种地板保持天然竹材的特色。色泽美观、自然、有弹性，容易铺装和移动。     

Floral biology and breeding behavior in the bamboo Dendrocalamus strictus Nees

Floral biology and breeding behavior were studied in the bamboo Dendrocalamus strictus Nees. The inflorescence in this species is a large branching panicle. Fertile florets are intermixed with smaller sterile ones. There are six stamens. The ovary is stipitate and turbinate. The style is long and the stigma is bifid and plumose. Dendrocalamus strictus is typically dichogamous and protogynous. The gynoecium matures 3-4 days before the androecium, effectively preventing self pollination. Flower bloom, which took place over a period of 2 to 3 h, was dependent on air temperature and only occurred between 0600 and 1300 h. Dendrocalamus strictus is anemophilous. Flowers in the male phase were visited by insects. These insects completely neglected the flowers at the female phase. The insects fed on the pollen and were not pollen vectors. When wind was excluded by enclosing the inflorescences in bags there was no seed set, indicating that cross pollination by wind is necessary for fertilization and that parthenocarpy and apomixis are not occurring in this species. Pollen fertility was about 98% as indicated by staining fresh pollen at the time of anther dehiscence and pollen release with Alexander's stain (Alexander 1969). When placed on a modified Brewbaker-Kwak medium containing 1% glucose, the pollen grains germinated well, and the pollen tubes grew to 15-20 times the diameter of mature pollen grains. Although profound protogyny has its disadvantages in times of sporadic flowering, it can be useful in breeding programs because it eliminates the need for emasculation.