抽提预处理沙柳的热解失重特性、动力学及产物组分

为了控制和改善沙柳原料热解产物品质,对比了热水、1%Na OH和苯-乙醇(苯醇)抽提3种预处理方法,利用热重红外分析法(TG-FT-IR)和热解气质联用(Py-GC/MS)研究了预处理对沙柳热解失重特性及产物生成规律的影响。结果表明:热水和苯醇抽提预处理降低了残炭率,促进了挥发性产物的生成,而1%Na OH抽提预处理增加了残炭率;Coats-Redfern动力学分析发现,抽提预处理沙柳低温段与一级动力学拟合较好,高温段与二级动力学拟合较好,抽提预处理降低了沙柳热解活化能,有利于沙柳热解反应的进行;经过1%Na OH抽提预处理沙柳生成了较多的酚和酮类组分,经过热水抽提预处理沙柳的醛类、酚类、酸类等物质GC含量减少而酯类、醚类GC含量增加,苯醇抽提预处理沙柳各组分GC含量变化不大。     

微波辅助山毛竹全组分分离

利用微波辅助加热,在丙酮/乙二醇二元溶剂体系中对山毛竹原料进行全组分分离,得到粗纤维素、木质素和生物基多元醇,并以得到的生物基多元醇为原料制备聚氨酯泡沫。对反应时间、反应温度、催化剂浓硫酸添加量以及两种溶剂比例等条件进行了优化,采用傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)和凝胶渗透色谱(GPC)等分析手段对分离得到的粗纤维素和木质素的结构进行了表征,分析了生物基多元醇添加量对制得的聚氨酯泡沫微观结构、力学性能和热稳定性的影响。结果表明:溶剂与物料的质量比为10∶1、反应温度为120℃、反应时间为20 min、浓硫酸添加量为1.5%(质量分数)以及丙酮/乙二醇二元溶剂的质量比为1∶1时,山毛竹全组分分离效果最好,粗纤维素得率为41.7%,木质素去除率和木质素回收率分别达到85.1%和72.3%。XRD结果表明,与原料相比,经过分离得到的粗纤维结晶度明显上升; GPC结果表明,分离得到的木质素分子量较小且分布均衡。通过对添加不同质量比生物基多元醇聚氨酯泡沫的性能对比可知,当生物基多元醇添加量低于50%时,聚氨酯泡沫可以保持较好的泡孔结构;但随着生物基多元醇的添加量逐渐增加,泡沫的力学性能和热稳定性有所下降。     

稻草秸秆同时糖化法产乙醇的动力学研究(英文)

在纤维素酶20 U/g,发酵温度38℃,接种量15%,管囊酵母和酿酒酵母的接种比例2∶1条件下,选择不同的固液比(1∶5、1∶10、1∶15和1∶20),研究了稻草秸秆同时糖化法产乙醇的动力学。结果表明:固液比1∶15时,获得了较高的乙醇产率为0.183 g/g,方程c=abt/(1+bt)可以被用来描述乙醇浓度(c)与发酵时间(t)的关系,动力学参量a随着固液比减小而减小,而动力学参量b随着固液比的减小而增加;同时,在不同固液比条件下,稻草秸秆转化乙醇反应被证明是类分形的,方程k=k1t-h能被用来很好的描述速率常数与发酵时间之间的关系。     

甜高粱秆酿酒前后化学组分纤维特性及制浆性能的研究

对甜高粱秆及其酿酒后残渣的纤维形态、化学组分进行观察和测定发现,甜高粱秆的发酵酿酒过程并没有对其纤维造成严重损伤,二者均具有较大的纤维平均长度和长宽比,且纤维形态良好.在化学组分上,甜高粱秆及其酿酒后残渣的综纤维素和α-纤维素含量较高,木素含量少,均是较好的造纸原料.制浆性能研究表明,甜高粱秆酿酒后残渣易蒸煮,用碱量低,得率高,成纸具有较好的物理强度,将甜高粱秆酿酒后残渣用于制浆造纸是合理利用酿酒残渣的有效途径.     

挤压预处理对杨木APMP浆纤维形态及制浆性能的影响

在相同的APMP制浆工艺条件下,以未挤压木片为对照样,考察了双螺杆挤压(TSE)和单螺旋挤压(MSD)对纸浆纤维形态及制浆性能的影响。研究结果表明:在相同制浆工艺下,挤压程度越高,纸浆的长纤维及纤维束含量越低。当加拿大游离度为250 mL时,TSE挤压所得纸浆含纤维束1.78%,相对MSD挤压降低了76.67%。此外,经TSE挤压所得纸浆的耐破强度和抗张强度均高于对照样和MSD挤压;而TSE挤压所得纸浆因长纤维含量较低,使得其撕裂强度低于对照样和MSD挤压。当加拿大游离度为250 mL时,TSE挤压所得纸浆白度为65.48%(ISO),较MSD挤压提高了9.14%(ISO),较对照样提高12.94%(ISO)。由于TSE挤压后木片浸渍时反应更充分,有更多的物质溶出,因此其所得纸浆得率(84.54%)低于MSD挤压(87.20%)和对照样(87.00%),且制浆过程产生废水的COD和SS值均较高。     

预处理方法对稻草中纤板性能的影响

采用热水、乙酸以及亚硫酸盐3种方法进行稻草预处理,找出经济可行的稻草中纤板预处理方法.结果表明:各种预处理均可改善板的性能,其中乙酸处理效果最佳.对密度为0.83 g/cm3的稻草MDF,当乙酸加量2%、处理温度80 ℃、时间20 min时,除TS指标外,试板的主要力学性能均可满足GB/T 11718-1999的要求.     

料慈竹不同年龄纤维形态的研究

就贵州省赤水市料慈竹（Ｂａｍｂｕｓａｄｉｓｔｅｇｕｓ）０～４ａ５个龄级的纤维形态进行显微观测和系统分析表明，其纤维长度为２．１３～２．６９ｍｍ（平均２．４５ｍｍ），纤维宽度为１３．４２～１５．０６μｍ（平均１４．０９μｍ），长宽比历８～１８５（平均１７４），壁厚２．５２～６．４６μｍ平均４．８６μｍ），腔径２．１５～８．３９μｍ（平均４．４１μｍ），壁腔比为０．６～６．１７（平均３．２４）。通过方差分析后表明，除纤维长度和宽度外，年龄对料慈竹纤维形态有一定影响，表现在纤维壁厚度上，从０～１ａ有增厚，１ａ后相对稳定，至４ａ时明显增厚；纤维腔径相反，从０～１ａ腔径减小，至４ａ时明显减小。     

13种食用菌对稻草生物降解能力的研究

通过对13种食用菌对稻草生物降解能力的研究,结果表明除蒙古白蘑(Tricholamamongolicum)外,其他12菌株对稻草中的木素及纤维素均有一定的降解能力。其中侧耳(Pleurotus.ostreatus)表现出了很强的木素降解能力及较低的综纤维素降解能力,其木素降解率为17.86%,综纤维素降解率为2.44%,SF指数为7.97,为理想的木素降解菌。其他菌株木素降解率为2.30%~16.54%,综纤维素降解率为5.60%~17.32%,而SF指数均较低,介于0.14~2.24。通过线性回归得出菌落直径与变色圈直径比值(d1/d2)和选择性指数(SF)为负相关,其相关系数r=-0.1476,相关性不大。表5参9。     

稻草原料酸碱性及稻草中密度纤维板的性能

测试分析了稻草原料的ｐＨ值和缓冲容量，分别使用脲醛树脂胶和异氰酸酯胶在特定工艺条件下压制了稻草中密度纤维板，并测试了板材性能。结果表明：１）稻草秸秆原料呈弱碱性，缓冲容量远高于普通木材；经热磨处理获得的稻草纤维呈弱酸性，其缓冲容量虽较稻草秸秆有一定幅度的下降，但仍高于普通木材；２）脲醛树脂或异氰酸酯稻草中密度纤维板的性能都明显优于相应的碎料板；在密度０．８０ｇ／ｃｍ３和施胶量１７％的条件下，脲醛树脂稻草中密度纤维板性能达到国标ＧＢ／Ｔ１７６５７－１９９９一等品的要求，在密度０．８０ｇ／ｃｍ３和施胶量６％的条件下，异氰酸酯稻草中密度纤维板性能达到国标ＧＭ／Ｔ１７６５７－１９９９优等品要求。     

稻草刨花板薄木贴面工艺

采用正交试验法探讨了各热压工艺因子对稻草刨花板薄木贴面的影响.试验结果表明:稻草刨花板表面饰贴薄木是切实可行的,进行0.2 mm厚水曲柳薄木贴面,在选用PVAC胶黏剂且涂胶量为100 g/m2的条件下,其较佳工艺参数分别为:热压压力为0.7 MPa、热压温度为100℃、热压时间为120 s;在选用GB-3胶黏剂且涂胶量为100 g/m2的条件下,其较佳工艺参数分别为:热压压力为0.8 MPa、热压温度为90℃、热压时间为180 s.进行0.6mm厚白橡薄木贴面,在选用PVAC胶黏剂且涂胶量为120g/m2的条件下,其较佳工艺参数分别为:热压压力0.8MPa、热压温度90℃、热压时间240 s;在选用GB-3胶黏剂且涂胶量为120g/m2的条件下,其较佳工艺参数分别为:热压压力0.7 MPa、热压温度90℃、热压时间180 s.     

无机复合型阻燃剂对稻草刨花板阻燃性能的影响

选用氢氧化铝(ATH)与硼酸锌(ZB)组成的无机复合型阻燃剂压制阻燃稻草刨花板,采用锥形量热仪法研究不同配比的ATH和ZB对稻草刨花板阻燃性能的影响。结果表明:无机复合型阻燃剂能有效减少稻草刨花板的热释放和烟释放,减少烟气中CO和CO2的释放浓度,降低燃烧过程中的质量损失速率,表现出良好的阻燃抑烟效果;ATH与ZB具有协同阻燃作用,ZB的加入能有效提高复合阻燃剂的阻燃效果,减少ATH的用量,10%的ATH用量可达到比较好的阻燃效果。     

The effect of urea pretreatment on the formaldehyde emission and properties of straw particleboard

For manufacturing low-formaldehyde emission particleboard from wheat straw and urea-formaldehyde (UF) resins using urea treatment for indoor environments, we investigated the influence of urea treatment on the formaldehyde emission, physical and mechanical properties of the manufactured particleboard. Wheat straws were treated at three levels of urea concentration (5%, 10%, 15%) and 95℃as holding temperature. Wheat straw particleboards were manufactured using hotpress at 180℃and 3 MPa with two types of UF adhesive (UF-45,UF-91). Then the formaldehyde emission values, physical properties and mechanical properties were considered. The results show that the formaldehyde emission value was decreased by increasing urea concentration. Furthermore, the results indicate that the specimens under urea treatment have better mechanical and physical properties compared with control specimens. Also specimens under urea treatment at 10% concentration and UF-91 type adhesive have the most optimum physical and mechanical strength.     

Chemical characteristics of straw fiber and properties of straw fiberboard with different pretreatments

Surface chemical characteristics of straw fiber have a great effect on the properties of interfacial conglutination between straw fiber and adhesives. In our study, straw was treated by four different methods—hot water, acetic acid, sodium sulfite and sodium hydrid sulfite. Our results show that the main chemical group of straw fiber, under the four different treatments, has not changed significantly. The acetic acid treatment reduces pH values of straw fibers and has a significant effect on the internal bonding strength of straw fiberboards. The modulus of rupture and modulus of elasticity did not clearly improve with the four different treatments. The thickness swelling of straw fiberboard treated in different ways is higher than that of standard values. It is concluded that acid treatment is optimal for producing good quality straw fiberboard. __________ Translated from China Forest Products Industry, 2006, 33(4): 24–26 [译自: 林产工业]     

Influence of forbs and shrubs on ruminal fermentation and digesta kinetics in sheep fed a grass hay/straw diet

Four ruminally cannulated, Debouillet wethers were used in a 4×4 latin square experiment to evaluate the influence of a forb mix, a shrub mix and alfalfa (ALF) hay on ruminal fermentation characteristics and digesta kinetics of a basal grass hay/straw (GH/S; 1.04% N) diet. The grass hay was mostly blue grama (Bouteloua gracilis) mixed with barley (Hordeum vulgare) straw. Wethers were fed either the GH/S mix (7030), GH/SALF (295813), GH/Sforbs (265420), or GH/Sshrubs (265420). The forb component consisted of equal parts of scarlet globemallow (Sphaeralcea coccinea) and leatherleaf croton (Croton corymbulosus) while shrubs were composed of equal parts of fourwing saltbush (Atriplex canescens) and mountain mahogany (Cercocarpus montanus). Ruminal pH, ammonia-N, as well as total VFA concentrations and molar proportions of individual VFA did not differ among diets. Particulate passage rates tended (P>0.10) to be greater for diets containing ALF, forbs or shrubs (2.8, 2.9 and 2.8% h^–1) than the GH/S diet (2.5% h^–1). In situ DM and NDF disappearance of a GH/straw (5050) mix did not differ among treatments at most incubation times, except at 96 h when extent of both DM and NDF disappearance were greater (P<0.05) in sheep fed either forbs or shrubs than in those fed other diets.     

Effects of silane coupling agent level and extraction treatment on the properties of UF-bonded reed and wheat straw particleboards

Urea formaldehyde resin bonded reed and wheat particleboards with a density of 0.7g/cm³ were manufactured from two types of particle: fine and coarse particles. The effects of the silane coupling agent (SCA) level and ethanol-benzene (EB) treatment on the board properties were examined. For SCA, epoxide silane (SiEP) and amino silane (SiNH) were used for reed and wheat particles, respectively. The results are summarized as follows. (1) For both reed and wheat boards, the internal bond (IB) strength and thickness swelling (TS) were significantly improved at up to 5% SCA content, but the effectiveness of treatment kept constant at above 5%. (2) The level of SCA had little effect on the bending strength, especially for the boards composed of coarse particles. (3) EB treatment upgraded both the IB and TS of wheat board significantly. (4) SiEP incorporation improved the IB and TS of reed board significantly, whereas EB treatment was more effective for wheat board. (5) The dimensional stability of both reed and wheat boards under varying humidity could be improved by increasing the level of SCA and by EB treatment. EB treatment was more effective than SCA addition.     

麦草纤维孔隙结构在回用过程中的变化规律研究

采用低温氮吸附法、透射电镜对不同回用次数下麦草纤维细胞壁孔隙结构进行了研究。结果表明,麦草纤维有发达的微孔,分布较宽的中孔,而大孔相对较少。麦草浆回用1次后微孔孔容下降3.2×10-5cm3/g,中孔孔容下降1.67×10-5cm3/g;2次和1次回用相比微孔孔容下降9.2×10-5cm3/g,中孔孔容下降2.77×10-5cm3/g;3次回用时微孔分布消失,与2次回用相比中孔孔容下降5.81×10-5cm3/g,但在3次回用后孔隙分布变化很小。孔隙平均孔径和BET比表面积在回用中总体呈下降趋势。从电镜照片上看出,纤维在回用再润湿后发生不可恢复的塌陷变形,细胞壁上出现褶皱,从而改变了纤维孔隙大小和形状。     

蒸汽爆破-乙醇蒸煮两步法预处理对麦秆结构的影响

对麦秆采用先蒸汽爆破后乙醇蒸煮的两步法进行预处理,研究预处理对麦秆组分及结构变化的影响。蒸汽爆破过程实验条件选取200 g绝干麦秆,压力1.75 MPa和时间3.5 min。乙醇预处理过程选取80 g蒸汽爆破麦秆(绝干),55%乙醇,两者固液比1∶5(g∶mL),温度170℃、时间30 min。通过高效液相色谱法测定,预处理最终产物组分中半纤维素降低89%左右,木质素降低35%左右。采用红外光谱、纤维形态分布分析及SEM分析对预处理过程中麦秆结构变化情况进行研究,结果表明:蒸汽爆破过程破坏了半纤维素酯键连接且半纤维素降解非常明显,但对纤维素链结构影响和降解作用相对较低;麦秆经过蒸汽爆破预处理后,纤维平均长度明显降低,而平均宽度却显著增加;再经乙醇预处理后纤维平均长度基本保持不变,但平均宽度降低;经两步预处理后麦秆纤维的天然物理结构由紧密到蓬松,纤维束呈松散状态且纤维表面基本无碎片附着物,利于后续加工利用。     

Effects of five additive materials on mechanical and dimensional properties of wood cement-bonded boards

There is a growing desire to improve the properties and use of nonwood plant materials as supplements to wood materials for wood cement-bonded boards (WCBs). This study was conducted to determine the comparative properties of WCBs containing various amounts of discontinuous inorganic fiber materials, such as alkali-resistant glass fiber, normal glass fiber, mineral wool, and nonwood plant materials such as retted flax straw and wheat straw particles. Tested cement-bonded boards were made at wood/additive compositions of 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 (weight percentages). Seventy-eight laboratory-scale WCBs were produced. Various board properties, such as the modulus of rupture (MOR), internal bonding strength (IB), water absorption (WA), thickness swelling (TS), and linear expansion (LE), were studied. The test results showed that three types of discontinuous inorganic fiber used as reinforcing materials in composites significantly enhanced and modified the performance of WCBs. The mechanical properties and dimensional stability of cement-bonded board were significantly improved with increasing amounts of the additives. MOR and IB were increased; and WA, TS, and LE of boards were reduced by combination with the inorganic fiber materials. The results also indicated that combination with retted flax straw particles only slightly increased the MOR of boards, and wheat straw particles led to marked decreases in all the mechanical properties and the dimensional stability of WCBs.Part of this report was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000     

秸秆在哈尼族民居建筑可持续更新中的节能性分析与应用前景

哈尼族民居建筑作为一种民族特色的物质文化遗产已经被传承了近千年,然而目前由于文化上的趋于大同以及地方经济的发展,各种形式的现代砖瓦建筑在逐步取代这些特色民居,导致了地方建筑文化的消失,以及对传统自然人居环境的破坏。秸秆作为一种建筑材料已经被使用了相当长的时期,在节能、经济、环保等多方面都具有其独特的优势,在哈尼族民居建筑的可持续更新过程中它具有十分重要的使用价值与应用前景。