共查询到16条相似文献,搜索用时 62 毫秒
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研究了马尾松硫酸浆两段氧脱木质素的最佳工艺条件。结果表明,第一段氧脱木质素的条件为:氧压0.6MPa,温度100℃,时间80min,NaOH 量5%,MgSO4用量0.5%,浆浓10%;第二段氧脱木质素的条件为:氧压0.4MPa,温度90℃,时间60min,NaOH用量3%,MgSO4用量0.5%,浆浓10%。在此条件下,OIOⅡ木质素脱除率达到72.5%,粘度775.2cm^3/g,得率90.5%。经过氧脱木质素后浆的裂断长5.8km,耐破指数5.3kPa.m^2/g,撕裂指数12.7mN.m^2/g。 相似文献
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研究了马尾松硫酸盐浆单段氧脱木质素的最佳工艺条件。结果表明 :氧压0 .6MPa、温度 10 0℃、时间 80min、NaOH用量 5%、MgSO4用量 0 .5%、浆浓 10 % ,在此条件下 ,纸浆木质素脱出率 4 7 1% ,氧脱木质素后纸浆粘度 94 8 1cm3/g ,白度 4 1 0 %(ISO) ,得率 96.9% ,经过氧脱木质素后浆的裂断长 6 3km ,耐破指数 5 8kPa·m2 /g ,撕裂指数 14 1mN .m2 /g 相似文献
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通过比较不同条件下氧脱木质素后浆料的卡伯值、黏度、得率、白度和脱木质素选择性等指标,研究了硫酸盐竹浆卡伯值25.6氧脱木质素工艺参数,发现用碱量和温度是决定氧脱木质素效果的主要因素.最佳工艺条件为:用碱量3.5%,温度85℃,氧气压力0.6MPa,保温时间80min.两段氧脱木质素(中间不洗涤)可以提高木质素脱除率和选择性.研究还发现,在氧碱脱木质素过程中加入醌类混合物助剂(表示为Oq),可使浆料的黏度和氧脱木质素的选择性大大提高.采用OQ(PO)、(O1O2)Q(PO)、OQ(PO)1(PO)2和OqQ(PO) 4种短漂序都可使竹浆白度达到80%(ISO) 以上,且具有很好的白度稳定性.OQ(PO)、(O1O2)Q(PO)和OQ(PO)1(PO)2 3种漂序漂后浆纸页强度性能相近,OqQ(PO)漂后浆的抗张指数、撕裂指数和耐破指数明显高于其它3种漂序. 相似文献
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为研究相思木自水解过程产酸行为及其对水解后木片硫酸盐法制浆的影响,在水热预处理强度指标P因子93~1 008的范围内进行木片自水解预处理,然后将一部分预抽提后木片通过超声波洗涤去除残留酸,将除酸处理后的预浸渍木片和对照样(即未进行超声波洗涤)以相同的条件进行硫酸盐法制浆。研究结果表明:自水解液(AHL)中产生的酸含量随预处理强度的增强而增大,导致AHL的pH值呈下降趋势;其中乙酸是主要酸成分,P因子606时乙酸质量浓度达到4.21 g/L,之后随自水解过程缓慢增加到P因子1 008时的4.41 g/L;P因子1 008时还检测到少量甲酸。超声波洗涤去除残留酸后木片蒸煮细浆得率比自水解木片提高了10.1%,同时纸浆Kappa值由31.24下降至19.69(P因子1 008),纸浆黏度没有明显变化,但纤维长度由0.76 mm下降至0.64 mm(P因子1 008),可能是导致超声波洗涤后木片纸浆手抄片的抗张和耐破强度轻微降低的原因。 相似文献
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对氧碱漂白过程中木质素氧化进行定量分析,分析方法是基于氧化前后高锰酸钾消耗量的变化。该方法对溶出残余木质素的氧化结果分析发现其呈明显3个阶段:第一段木质素氧化的当量电荷数约4~5/木质素单元;木质素总氧化电荷数大约为9/木质素单元。这些数据以及甲氧基的脱除(75%)均表明:木质素的氧化不仅发生在酚型木质素单元,同时也发生在非酚型结构单元上。只有第一阶段氧化反应是木质素与氧气直接反应,而在第二、三阶段主要是协同氧化作用,氧化反应过程中产生的活性氧基团扮演了一定角色。通过对低浓度针叶材硫酸盐浆的氧漂研究发现:当卡伯值下降一半(25.4至13.4)时平均每个木质素单元氧化3当量电子,氧漂后的纸浆中仍然有大量未被氧化的残余木质素。定量地证明了在氧漂过程中木质素氧化是脱木质素反应的实质。 相似文献
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用酶预处理针叶木硫酸盐浆,再进行CEDED程序漂白。CE段结束后浆料的卡伯值有明显的降低,漂白终点的纸浆白度有提高,可以节省氯化段有效氯的用量。 相似文献
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相思树硫酸盐浆无元素氯漂白性能的研究 总被引:1,自引:1,他引:0
系统对比研究了大叶相思、马占相思、厚荚相思及纹荚相思4种相思树硫酸盐法制浆性能及无元素氯(ECF)漂白性能。结果表明,采用硫酸盐法制浆,用碱量(氧化钠计)16%、硫化度25%时,制得的4种相思树硫酸盐浆经OPDP1P2(OP为氧强化脱木质素,D为ClO2漂,P为H2O2漂)4段漂白,漂后纸浆的光学性能及强度性能优良。纸浆白度均达86.0%(ISO,以下同)以上,叩解度为30°SR时,抗张指数在55.8~60.7N·m/g之间。4种相思树中大叶相思的制浆性能最优,马占相思和纹荚相思居中,厚荚相思的制浆性能最差。 相似文献
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ZHANG Yang JIANG Hua ZHANG Yijia Nanjing Forestry University Nanjing P.R.China 《中国林业科技(英文版)》2007,6(4):25-30
The biology treatment of cellulases or hemicellulases is used in this paper. The effects of cell ulases and hemicellulases on surface wettability and gluing property of poplar and wheat straw were investigated. It was found that the surface contact angles of poplar and wheat straw were reduced and the surface free energies were increased after treatment by these enzymes. The gluing strengths of popular and wheat straw were enhanced with the increases of the dosage of enzymes and the time of enzymatic treatment. 相似文献
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Seed morphology, germination and seedlings growth of Acacia auriculiformis were studied. The experiment was conducted in the nursery of Forestry and Wood Technology Discipline, Khulna University,
Bangladesh. Matured seeds of the species were collected from healthy trees of road side plantation from different areas of
Khulna District, Bangladesh and treated with five pre-sowing treatments (control, immersion in cold water, immersion in hot
water, scarification with sand paper and immersion in concentrated H2SO4). The average length, breadth and thickness were found to be (0.58±0.017) cm, (0.44±0.007) cm and (0.20±0.089) cm, respectively.
Germination was conducted in polybags with a mixture of top soil, coconut husk, coarse sand, and fine sand in a ratio of 3:4:1:1.
Results reveal that pre-sowing treatments influences the germination rates of seeds that significantly increase the percentage
germination compared with those in control (43%) and cold water treatment (52%). The highest germination success rate was
found 83% in hot water treatment followed by 78% in scarification with sand paper, and 75% with immersion in H2SO4. Germination started from 7 to 12 days and completed between 28 and 35 days period in all treatments. ANOVA showed the significant
difference (p<0.05) among the treatments in seed germination, but no significant difference among treatment with regard to starting day,
closing day and total germination period. In case of height and diameter growth, seedlings originated from the seeds with
hot water treatment shows significantly higher in wet season (from May to July). Hot water treatment can be recommended on
seed germination of the species in rural Bangladesh. 相似文献