共查询到19条相似文献,搜索用时 671 毫秒
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为解决普通脲醛(UF)树脂对芦苇材料胶合性能差的问题,以聚乙烯醇/三聚氰胺改性脲醛(PVA/MUF)树脂为胶黏剂制备芦苇刨花板。通过正交试验,研究密度、热压温度、热压时间、施胶量等因素对板材内结合强度(IB)、静曲强度(MOR)以及2 h吸水厚度膨胀率(TS)的影响。结果表明:芦苇刨花板的优化制备工艺为:密度0.85 g/cm3、热压温度160℃、热压时间5 min、施胶量12%。所制得的芦苇刨花板IB和MOR分别为1.00 MPa和21.4 MPa,与木材刨花板相当。未来,使用PVA/MUF树脂改性胶黏剂制备的芦苇刨花板有望替代传统木材刨花板。 相似文献
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工业大麻秆是一种优质的轻质非木质原料,利用脲醛树脂为胶黏剂可以制备出性能优良的刨花板产品.笔者主要分析不同的工艺参数,包括密度、热压时间、热压温度和施胶量对板材性能的影响.研究结果表明,密度和施胶量对板材性能的影响要比热压温度和热压时间明显,随着板材密度、热压温度和热压时间的增加,板材的力学性能大多先增加后减小;而随着施胶量的增加,板材的力学性能呈增加趋势.在目标密度0.55 g/cm3,施胶量10%,热压温度130℃或170℃条件下,板材的力学性能可达到国标普通刨花板的标准要求;当目标密度等于或高于0.65 g/cm3、施胶量等于或高于12%、热压温度在140~ 160℃、热压时间在20 ~ 45s/mm之间时,除TS外,板材的其他力学性能可达到国标室内装饰和家具用材的标准要求,并可与相同工艺条件下,目标密度为0.75 g/cm3的木质刨花板的各项性能相媲美.可见,工业大麻秆是一种优质的非木质原料,利用该原料在低温条件下制备低密度的刨花板是可行的. 相似文献
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分析了蓖麻秆的供应现状和蓖麻秆的原料特性,认为蓖麻秆用作人造板工业化生产是可行的;并在实验室试制了蓖麻秆刨花板和蓖麻秆纤维板,按照相关国家标准测试了板材的主要性能.结果表明,当脲醛树脂胶施胶量为12%、热压温度180℃、热压时间30 s/mm、板材密度为0.8g/cm3时,蓖麻秆刨花板的主要性能均能达到国家刨花板标准要求;当施胶量达到16%、热压温度180℃、热压时间30 s/mm、密度为0.86 g/cm3时,不添加防水剂的蓖麻秆纤维板除了吸水厚度膨胀率外,其余指标均能达到国家标准要求. 相似文献
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初步探讨了实验室条件下烟秆/木材刨花板的生产工艺,研究了热压时间、施胶量、密度、木刨花加入量等因素对板材的静曲强度、内结合强度、吸水厚度膨胀率的影响.实验结果表明,烟秆/木材刨花板的静曲强度和吸水厚度膨胀率较纯烟秆刨花板有所提高,内结合强度相差不大. 相似文献
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为合理开发利用木薯秸秆,扩大造纸及纤维板生产原料来源,就其化学成分及应用进行研究,结果表明:4年生木薯秸秆的纤维素含量(44.70%~49.74%)和木质素含量(27.06%~27.45%)与9年尾叶桉、18年火炬松相当,热水抽提物含量(9.58%~17.90%)是这两种木材的2~4倍;1年生木薯秸秆的纤维素含量(34.37%)低于棉秸秆、烟秸秆和豆秸秆,木质素含量(36.25%)和热水抽提物含量(24.94%)高于这些农作物秸秆;采用木薯秸秆制浆时应注意溶出物对生产的影响;1年生木薯秸秆木质部粗蛋白5.46%、钙0.33%、粗脂肪0.11%,髓心粗蛋白1.49%、钙1.09%、粗脂肪0.32%;木薯秸秆收集和贮存时应重视防腐和防虫。 相似文献
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Market-oriented production of gardening crops and cassava (Manihot utilissima) in the dry season is an increasingly frequent practice in Ségou, Mali. Traditionally, these crops are protected from roaming
livestock with the help of dead fences. In order to provide a sustainable alternative to dead fences, the International Centre
for Research in Agroforestry (ICRAF) began promoting the use of live fences, living trees planted closely together around
a field plot. This study was conducted with the first farmers to use these live fences. These farmers expressed satisfaction
with the protection offered by the trees and their ability to provide a variety of medicinal, economic, and food products.
The form of land tenure, the social status of farmers within their families, and the availability of labour seem to be important
factors in the decision to test the live fence. This raises questions about the accessibility of this technique and its possible
contribution to the social and economic differentiation of its users.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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采用氢氧化钠/尿素混合水溶液对木薯淀粉进行预处理活化,研究了预处理对木薯和松香酶法合成松香淀粉酯的影响。通过SEM、FT-IR和XRD等表征方法研究了预处理对木薯淀粉颗粒形貌和结晶结构的影响,结果表明,木薯淀粉经预处理后,淀粉粒仍保持一定圆形或椭圆形结构,但是其表面有破面和裂缝;预处理淀粉结晶结构遭到一定程度破坏,结晶度降低。对比分析木薯淀粉及预处理木薯淀粉的理化性质发现,预处理后的木薯淀粉在冷水中的溶解率由7.5%增加到45.7%,提高了38.2个百分点,透明度由86.6%增加到95.7%,增强了9.1个百分点,相对黏度降低。以松香为原料,固定化脂肪酶为催化剂,分别与木薯淀粉和预处理木薯淀粉进行酯化反应,考察预处理对酯化反应取代度的影响。结果表明,经预处理后的木薯淀粉与松香反应的取代度高达0.102,相比预处理前松香淀粉酯的取代度0.016明显提高。FT-IR分析表明,预处理后木薯淀粉酯化后的松香淀粉酯在1720 cm-1处产生明显的酯羰基CO伸缩振动吸收峰,其化学反应活性明显提高。 相似文献
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An alley cropping plot was established in 1990 on a degraded alfisol on sloping land at Ajibode village near the University
of Ibadan, Nigeria. The influence of Glomus deserticolum on biomass production of three hedgerow trees i.e., Leucaena leucocephala,
Gliricidia sepium and Senna siamea, and their nutrient contribution to cassava Manihol esculenta in four consecutive cropping
seasons were investigated. Inoculation only promoted hedgerow leaf-biomass and nutrient (N, P, and K). contribution to cassava
and consequently cassava tuber yield in the second year but did not affect them afterwards despite increased AM infection.
Tuber yield declined with succeeding cropping seasons in all plots except uninoculated plots with Senna where it showed 142%
and 11.5% increases respectively at 2 and 3-months pruning regime when compared with the first year’s yield. Biomass production
increased marginally with age in all hedgerows with concomitant increase in leaf production depending on partitioning of assimilates
between leaf and stem. Generally, hedgerow biomass diversion to leaf was higher at 2 than at 3-month pruning regime and was
in the order Senna Gliricidia Leucaena. Hence, while Senna provides sustained adequate leaf mulch to cassava, pruning at quarterly
interval during the first pruning year and at bimonthly intervals in subsequent years is also recommended. 相似文献
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The interactions between component species in three-tier agroforestry systems were studied on sloping laterite soils of South India for three years. The wood yield of Eucalyptus was found to increase in association with the intercrops, with cassava + groundnut resulting in the best growth of Eucalyptus. Green forage yield of Leucaena was adversely affected by cassava but was improved by inclusion of a short duration seasonal crop. Both spread and mean length of lateral roots of Eucalyptus and Leucaena were restricted by cassava intercropping. Both the tree species were found to reduce the tuber yield of cassava and also the pod yield of both the seasonal crops when grown in association. Monocropping with cassava was found to improve the fertility and an increase in phosphorus and potassium contents of the soil was observed when grown in association with Eucalyptus and Leucaena. Soil fertility fell considerably after three years of cultivation of the tree species. The nutrient uptake by cassava was low when grown in association with perennial species. Both run off and soil loss were effectively reduced when cassava was grown in staggered mounds under Eucalyptus and Leucaena. 相似文献
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充分有效地利用木薯产业剩余物,对广西林木资源和环境保护有着重要的理论和现实意义.对木薯(Manihot esculenta)粗根的纤维形态、组织比量和化学成分进行了研究分析,结果表明:木薯粗根纤维的平均长度818 μm,宽度26.95 μm,双壁厚7.14 μm,长宽比31.34,壁腔比0.37,属于短长度纤维原料.组织比量测定结果:木纤维66.91%,导管4.88%,木射线22.37%,轴向薄壁组织为5.84%.木薯粗根化学组成中各组分质量百分数:水分8.57%,灰分3.53%,冷水抽出物6.78%,热水抽出物7.29%,1%NaOH抽出物24.28%,苯-醇抽出物2.58%,纤维素为42.80%,综纤维为76.93%,酸不溶木素为26.85%. 相似文献
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研究了糠醛渣(FR)经不同强度绿液-过氧化氢预处理脱木质素后,与木薯渣(CR)混合进行同步糖化发酵生产乙醇,通过改变原料底物浓度、纤维素酶用量和添加无患子表面活性剂来优化混合底物同步糖化发酵条件,并分析了发酵过程中乙醇和副产物的浓度变化。结果表明,在糠醛渣预处理条件为:底物质量浓度5g/L、温度80℃、H_2O_2用量为0.6g/g、绿液用量为2mL/g(以糠醛渣计)预处理时间3h,在此条件下糠醛渣木质素脱除率可达56.5%。同步糖化发酵产乙醇条件为无患子皂素表面活性剂添加量0.5g/L,纤维素酶用量12FPU/g,纤维二糖酶用量15IU/g,预处理后的糠醛渣与木薯渣混合作底物(质量比为2∶1),底物质量浓度200g/L时,发酵120h最终乙醇质量浓度可达56.6g/L,乙醇得率为86.3%。同步糖化发酵过程中添加无患子皂素表面活性剂不仅降低了纤维素酶用量,还可延缓副产物乳酸的形成,减小甘油生产波动。 相似文献