玉米苞叶及其纤维的基本结构与性能

为更好地开发利用玉米苞叶资源,采用数字式织物厚度仪、电子织物强力仪、傅里叶变换红外光谱仪、扫描电子显微镜、Ｘ 射线衍射仪对其进行基本测试。通过测试与分析发现：玉米苞叶厚度及横纵向抗拉强度随苞叶层数由外至内逐渐降低;玉米苞叶主要含有纤维素,半纤维素和木质素;经化学处理后的纤维,其纤维素含量达到４３.７９％,半纤维素和木质素含量有所降低;玉米苞叶表面凹凸不平,有随机分布的孔洞,单纤维横截面形状不规则且内部有大中腔,纵向表面较为光滑平整;玉米苞叶结晶度约为３８.９０％,纤维结晶度为５７.８５％,二者均表现为纤维素Ⅰ的晶体结构。     

玉米苞叶膳食纤维的制备研究

在玉米的生产利用中,大量的玉米苞叶没有得到利用,而是作为一种废弃物。本文研究从玉米苞叶中,采取酶化法及化学法从中得到了膳食纤维。本工艺简单易行,且得到的膳食纤维较完全,得率是48.36%;持水力是3.716g/g;膨胀力是1.72mL/g。     

NaOH溶液制备玉米苞叶纤维的初步研究

玉米苞叶有着丰富的研究价值,采用不同浓度NaOH溶液制备玉米苞叶纤维,发现1%以上浓度的NaOH溶液都能制备玉米苞叶纤维,实验结果为今后的深入研究奠定基础。     

亚麻增强聚丙烯复合材料薄板的冲击性能

以亚麻纤维为增强体,与聚丙烯(PP)树脂长丝进行丝束级混合,形成PP包覆亚麻的纱线结构,利用机织工艺织成二维机织布,作为复合材料的预制件。采用层合热压的方法制备亚麻/PP复合材料薄板。通过对板材冲击性能的测试以及破坏形貌的分析,研究了亚麻/PP薄板的冲击破坏机制以及影响板材冲击性能的因素。结果表明:斜纹组织板材的冲击性能优于相同制备工艺的平纹组织板材;树脂、纤维、铺层数、冲击速度等因素对板材的冲击性能均有影响。     

复合酶法玉米苞叶纤维脱胶工艺研究

为拓展玉米苞叶的精深加工、提升玉米苞叶纤维的应用价值,采用复合酶对玉米苞叶脱胶,以质量损失率和残胶率为响应值,探究木聚糖酶、果胶酶和漆酶组成的复合酶系对玉米苞叶脱胶的最佳工艺。采用光学显微镜观察胶质的脱除和纤维表面的形态。研究结果表明：复合酶最佳脱胶条件为：木聚糖酶0.2 g/L、果胶酶0.3 g/L、漆酶0.1 g/L,酶处理时间为48 h, pH值为4.6,料液比为1∶50,酶处理温度为45℃;在此条件下,玉米苞叶纤维的质量损失率为45.52%,残胶率为50.22%;复合酶脱胶后的玉米苞叶纤维表面较为光滑平整,纤维上没有胶杂质黏附。     

纤维增强聚丙烯复合材料研究进展

聚丙烯作为常用的商品聚合物之一,因其耐紫外性差、易氧化等缺点限制了其应用,因此生产聚丙烯复合材料是拓展聚丙烯使用范围的途径之一.目前多种纤维可用作热塑性聚丙烯基体的增强材料,从纤维素纤维、有机合成纤维、无机纤维对纤维增强聚丙烯复合材料进行了论述,并从复合原料、界面相容方法等方面分析聚丙烯复合材料发展现状及存在的问题,提...     

纤维增强复合材料动态拉伸力学性能的研究进展

阐述了国内外对于纤维增强复合材料动态拉伸力学性能的研究进展,并介绍分离式压杆装置(Split HopkinsonPressureBar,SHPB)应用于冲击拉伸的实验原理,提出了进一步研究编织复合材料相关力 学性能的期望。     

纤维增强复合材料的性能及机械加工技术

文章在浅析纤维增强复合材料的性能后,重点分析和研究了不同类型的纤维增强复合材料的机械加工技术,在提出机械加工过程中需要注意的事项后,以为提升机械加工的效率和质量提供了依据,也为相关行业的技术人员带来了现实帮助。     

环保型剑麻纤维/聚丙烯复合材料的研究进展

简述剑麻纤维(SF)的组成、结构及力学性能,聚丙烯(PP)的加工特性.综述国内外对剑麻纤维增强聚丙烯复合材料的研究现状,并对其研究进展进行了展望.     

蔗渣纤维增强水泥基复合材料的研究

研究一种以水泥为胶凝材料、蔗渣纤维为增强相的复合材料的制备方法,探讨基体相、纤维相以及界面相的复合机理及其纤维含量对复合材料性能的影响。试验结果表明,蔗渣纤维经过预处理后,纤维与水泥浆体之间的接触面积增大,有利于纤维与水泥基材料的粘结,起到了增强复合材料的作用。当蔗渣纤维的添加量为15%时,材料综合性能最好。     

玉米苞叶纤维素纳米晶的制备及其聚砜复合膜的抗污染性能

为了提高玉米苞叶的经济价值,以玉米苞叶为原料,采用高强度超声波法制备纤维素纳米晶(CNC),并协同共混相转化法制备聚砜(PSF)/CNC复合膜。采用扫描电子显微镜、透射电子显微镜、X射线衍射以及超滤装置测试了CNC和PSF/CNC复合膜的形态结构和性能;探讨了CNC含量对复合膜的强度,亲水性,水通量以及抗污染性能的影响。结果显示,从玉米苞叶中提取的CNC,平均直径为18.82 nm,平均长度为569.95 nm,晶型结构为纤维素I型,结晶度为53.86%。CNC的加入提高了PSF膜的断裂强度,并可改善PSF膜的亲水性和抗污染性能。综合考虑CNC对PSF复合膜结构和性能的影响,得出CNC最佳添加量为2%,相应复合膜的水通量和抗污染性能分别为纯PSF膜的2.13倍和1.32倍,蛋白质截留率为48.34%。     

玉米皮半纤维素/壳聚糖/甘油复合膜制备及性质研究

以玉米皮半纤维素、壳聚糖和甘油共混制备复合膜,研究了玉米皮半纤维素、壳聚糖和甘油添加量对复合膜力学性质的影响,考察了复合膜的结晶结构、表面形貌、热稳定性、抗菌性能、降解性能、热溶解性和透光性。结果表明,当玉米皮半纤维素浓度为2.4%,壳聚糖浓度为0.6%,甘油浓度为0.4%时,做出的复合膜具有较好的抗拉强度和断裂伸长率。X-射线分析表明,半纤维素结晶结构未发生实质性变化,SEM和DSC分析表明,复合膜具有较好的表面特性和热稳定性,制得的复合膜对大肠菌群和金黄色葡萄球菌具有一定的抑菌效果,并且具有较好的降解性、热溶解性和透光性。     

Combined chemical and enzymic treatments of corn husk lignocellulosics

The potential for using corn (Zea mays L) husk residues (carbohydrates 827 g kg^?1, lignin 66 g kg^?1 DM) as a carbohydrate source for the production of soluble sugars by combined chemical pretreatment and enzymic hydrolysis was assessed. Comparative investigations of acidic and alkaline pretreatments on corn husk have shown that pentose-containing carbohydrates comprised 86–93% of the solubilised fraction. While pretreatments with 1.25 M NaOH at 25.85° C resulted in preferential extraction of hemicellulose having DP; > 12, acid pretreatments 0.51 M H₂SO₄, 0.51 M H₃PO₄ at (85° C) resulted in extensive depolymerisation of this polysaccharide. Xylose and low molecular weight carbohydrates were identified as the major products. Subsequent hydrolysis of the solubilised fraction with crude hemicellulase preparations yielded 40.90% fermentable sugars. When NaOH (0.02–1.25 M), H₂SO₄ and H₃PO₄ (0.02–0.51 M) were used as pretreatment solvents (25–85° C, 2 h), NaOH was the most effective in increasing the susceptibility of the residual husk towards enzymes, yielding 83–96% reducing sugars. This solvent solubilised up to 60.6% of the lignin and appeared to disintegrate the fibrillar structure of husk. The crystallinity of husk residues increased following the chemical pretreatments and was positively correlated with cellulose content. Enzymic hydrolysis with commercial cellulase preparations proceeded in two stages: a rapid breakdown of amorphous cellulose after which the hydrolysis rate levelled off. Similar biphasic patterns were observed for the pyrolysis temperature of cellulose. Under the most optimal conditions for husk saccharification (pretreatment with 1.25 M NaOH, 25° C, 2 h, followed by enzymic hydrolysis using a mixture of cellulase and cellobiase), 96% of the cellulose-enriched residues was hydrolysed to reducing sugars. A cellulase preparation from Trichoderma reesei exhibited substantial hemicellulolytic activity and could, therefore, be used as the sole saccharifying enzyme preparation for husk lignocellulosics.     

玉米皮纤维水刺非织造材料的制备及性能

采用碱处理法提取玉米皮纤维,并研究不同NaOH溶液浓度条件下玉米皮纤维的提取情况。采用气流成网法与水刺法,按不同纤维质量配比(5∶5、4∶6、3∶7)制备玉米皮纤维/黏胶纤维水刺非织造材料,并测试其厚度、单位面积质量、顶破性能、拉伸性能、柔软性及吸水性,结果表明玉米皮纤维/黏胶纤维(5∶5)水刺非织造材料的顶破强力可达到145.8 N,其纵横向拉伸断裂强力分别为89.5、74.5 N,而玉米皮纤维/黏胶纤维(3∶7)水刺非织造材料的抗弯刚度和吸水率分别为1.69 mN·cm、780.19%。     

Effects of enzymatic treatments on the mechanical properties of corn husk fibers

Corn husk fibers were extracted by water retting, alkalization, and enzymatic processes at different concentration and duration levels. The effects of extraction process parameters on the mechanical and thermal properties and chemical characteristics of corn husk fibers were investigated. Chemical structures of the fibers were studied by IR measurements. The finest and the stiffest fibers were produced by water retting followed by an enzymatic treatment. The highest breaking strength and breaking tenacity were obtained by water-retted fibers. While resulting in loss of breaking tenacity and elongation in water-retted fibers, enzymatic treatment resulted in increase in initial moduli and breaking tenacity of alkalized fibers. No significant effect of enzymatic treatment duration was obtained on the mechanical properties of corn husk fibers. Alkalized fibers gave higher elongation and lower stiffness compared to water-retted ones. The IR spectra showed higher amount of lignin and hemicellulose in water-retted fibers compared to alkalized and enzyme-treated ones. Enzymatic treatment and alkalization enhanced the thermal durability of the fibers. The ranges for properties of the produced corn husk fibers can be summarized as a linear density 17.0–25.6?tex, initial modulus 150.9–401.8?cN/tex, breaking tenacity 6.8–21.7?cN/tex, and elongation 9.6–18.2%.     

微生物分离玉米皮水解液中L-阿拉伯糖的研究

比较几株酵母菌和霉菌对玉米皮水解液中L-阿拉伯糖的分离情况,从中选出能够快速利用葡萄糖和木糖,难以利用L-阿拉伯糖的菌株。选用5株酵母菌,7株霉菌和自环境中分离筛选出的2株霉菌经模拟培养基发酵后筛选出5株菌进行对玉米皮水解液的发酵。结果表明,球拟酵母发酵4d,绿木霉、灰霉和自环境中分离筛选出的霉菌Mgb1、Mgb2发酵3d后,玉米皮水解液中木糖的保留率均小于5%,L-阿拉伯糖的保留率可达75%以上。分离方法简单有效,所用的3种菌株常见易得,为微生物法分离L-阿拉伯糖提供了一定的参考。     

The effects of the addition of corn husk fibre,kaolin and beeswax on cross-linked corn starch foam

Significant efforts have recently been made to improve the physical properties of starch foams formed using baking processes. For example, cross-linking starch with 0.126 g/kg glyoxal considerably reduces the baking time, density and water absorption of starch foams. In this study, we attempted to further develop the physical properties of glyoxal cross-linked starch foam by adding corn husk fibre, kaolin, beeswax and combinations of these products. We also studied the effects of these components on the microstructure and physicochemical and mechanical properties of trays. Starch-based trays in which additives were used showed improved water resistance. The water absorption capacities of the trays were 13%, 14% and 9% when combinations of kaolin/beeswax, fibre/beeswax and fibre/kaolin/beeswax were added, respectively.     

浑浊型玉米浆玉米须复合饮料的研制

研究浑浊型玉米浆玉米须复合饮料的制备工艺。重点探讨糖、酸等辅料添加量,复合稳定剂配方及均质工艺对产品品质的影响。结果表明,该复合饮料的最佳配方为玉米原浆与玉米须提取液体积比1∶1,蔗糖7%,乳酸0.03%,盐0.10%,琼脂0.02%,黄原胶0.1%,CMC 0.15%,蔗糖酯0.1%;最佳均质工艺为二次均质工艺,处理温度60℃,第一次均质压力20MPa、第二次均质压力25MPa。     

超声辅助碱性过氧化氢法提取玉米皮纤维素及结构表征

以玉米皮为原料,建立了超声波辅助碱性过氧化氢法提取玉米皮纤维素的方法,在单因素实验基础上,运用响应面法对玉米皮纤维素的提取工艺进行了优化,并利用扫描电镜、傅里叶变换红外光谱仪、X-射线衍射仪、热重和粒度分析仪对玉米皮纤维素进行表征。结果表明,玉米皮纤维素最佳提取工艺条件为:超声温度为70℃、超声时间为70min、超声功率为200W、NaOH质量分数为8%、H2O2体积分数为0.7%、料液比为1:30g/mL,在此条件下纤维素含量为83.34%。表征结果表明,玉米皮纤维素表面呈现纤维素聚集结构;玉米皮纤维素分子结构没有受到破坏,具有纤维素特征吸收峰; 玉米皮纤维素的结晶结构未发生改变,玉米皮纤维素的最大热分解温度为328℃,热稳定性优于玉米皮;玉米皮纤维素粒径减小,平均粒径为111μm。     

木纤维-聚丙烯原料及复合材料的热解特性研究

利用热重分析仪对木纤维-聚丙烯(PP)复合材料及其两种主要原料在静态空气中的热解特性进行了研究.试验结果表明:木纤维在热解过程出现两次失重峰,在第一燃烧阶段,活化能比较稳定,平均72.83 kJ/mol;燃烧第二阶段热解复杂.聚丙烯属于单峰失重,初始热解活化能为127.77 kJ/mol,随着温度上升活化能降低,甚至低于木材活化能,但综合比较热稳定性聚丙烯比木纤维高.木纤维-聚丙烯复合材料表现出两种原料共同促进了热解、燃烧的现象.