纤维表面润湿性能及其与纤维结合性能的响应关系研究

对南方松热磨机械浆纤维进行PFI磨浆处理,通过"液桥法"分析纤维接触角,进而计算表面能用于表征纤维表面润湿性能,最终建立纤维表面润湿性能与纤维结合性能之间的响应关系。结果表明,随着机械处理程度的加深,纤维表面木素含量从87. 13%降低到77. 51%,纤维表面润湿性能得到改善(表面能从46. 63 m J/m~2上升到54. 45 m J/m~2,表面电荷从48. 382 mmol/kg上升到60. 382 mmol/kg),结合强度指数从4. 63 N·m/g提升到10. 9 N·m/g。实验发现,纤维表面润湿性能与结合强度指数以及纸张的松厚度之间存在二次函数关系,且相关系数均大于0. 9。从表面润湿性能与松厚度之间的关系方程可知,纸张松厚度随纤维表面润湿性能降低而降低的较小,在整个机械处理过程中从4. 95 cm~3/g下降到3. 57 cm~3/g,这表明可通过改善纤维表面润湿性能来达到在不显著影响纸张松厚度的前提下提高纤维结合性能的目的。     

漆酶催化体系下明胶对麦草纤维交联性能的影响

以麦草为原料生产的纤维板和纸张的强度(尤其是湿强度)主要取决于纤维间化学键的交联程度。漆酶能催化纤维中的木素和明胶之间的共聚反应,在纤维之间产生化学键的结合。在本研究中,利用漆酶催化共聚产生木素-明胶之间的化学键的连接并将其用于提高麦草纤维板和纸张的物理性能。实验结果表明:在漆酶加入后,水解后的明胶能大幅提高纸张的抗张指数和耐破指数,酸水解明胶和酶水解明胶的抗张指数达64.58N.m/g和65.40N.m/g,相比空白试样分别提高了22.40%和23.96%,耐破指数为3.945kPa.m2/g和4.038kPa.m2/g,相比空白试样分别提高了37.55%和40.79%。同样,漆酶催化下添加酶水解明胶协同工业木素时制得纤维板的静曲强度(MOR)、弹性模量(MOE)、内结合强度(IB)、24h吸水厚度膨胀率(TS)分别达到29.3MPa、3204MPa、0.62MPa和10.23%,各项性能指标均达到GB/T11718-2009中纤维板的指标要求。     

桉木CTMP浆纤维表面木素对纸张强度的影响

通过对桉木CTMP浆纤维表面化学特性变化的研究,探讨了纤维表面木素对纸张强度的影响。通过正交试验和单因素试验结合的方法研究了漆酶处理桉木CTMP的适宜条件,并通过XPS、AFM分析纤维表面木素对纸张强度的影响。结果表明漆酶处理未漂桉木CTMP对纸张强度影响的最佳条件为:漆酶用量5 LAMU·g-1,温度50℃,介体用量0.05%,pH值5.0,处理时间90 min,通氧气,此时抗张指数14.39 N·m·g-1,撕裂指数5.95 mN·m2·g-1,耐破指数0.58 kPa·m2·g-1。     

沉析纤维尺寸效应对PET纸结构与性能的影响

本研究对自制聚对苯二甲酸乙二醇酯(PET)沉析纤维进行筛分处理，并与PET短切纤维混抄成纸，探讨了沉析纤维的尺寸效应对PET纸结构、机械及电气性能的影响。结果表明，筛分目数为100、含量50%的PET沉析纤维成纸性能最好，PET纸匀度指数达94，抗张指数56.2 N·m/g，撕裂指数42.9 mN·m~2/g，层间结合强度79.4 N·m/g，耐压强度9.51 kV/mm。     

聚乙烯亚胺／环氧氯丙烷增湿强剂的制备及其作用机理

通过环氧氯丙烷(ECH)对聚乙烯亚胺(PEI)进行改性,制备出具有强阳离子性和反应活性的改性PEI增强剂.研究了改性PEI对纸张的增强作用,并用流变仪、FTIR和SEM对其流变性能、分子结构及纸样微观结构进行了表征.结果表明,改性PEI可使湿抗张指数从3.23 N·m/g增加到6.49 N·m/g,湿强度保留率从14.3%增加到26.5%,且具有优异的助留性能;产物分子结构中出现了季铵基团;SEM分析表明,纸张断裂是由纤维断裂引起的,为改性PEI可增加纤维间的结合强度提供了依据.     

漆酶处理改善二次纤维强度性能的研究

采用漆酶对二次纤维进行处理,探讨了酶处理温度、时间、浆浓和酶用量对二次纤维的物理化学性质及成纸强度性能的影响。结果表明:在漆酶处理温度30℃、处理时间0.5 h、处理浆浓10%、漆酶用量500 mg·kg~(-1)的条件下,浆料成纸的耐破指数、耐折度和环压指数分别为2.15 kPa·m~2·g~(-1)、24次和9.17 N·m·g~(-1),分别比对照样提高16.22%、33.33%和4.56%。微观结构分析表明漆酶处理实现了浆料中木素的部分降解,改善了纤维润胀性能,增加了羟基含量。因此,漆酶处理是改善二次纤维强度性能的有效手段。     

一种富含灵芝的中药渣用于纸张抄造的初步研究

将一种富含灵芝的中药渣进行机械磨浆和筛浆后抄造得到纸张。探讨了不同磨浆条件对成纸抗张强度、耐破强度、撕裂度等性能的影响。结果表明,在一段磨浆、盘磨间隙为1.0mm、筛除粗渣和杂细胞的条件下,纸浆得率约为64%,纸页的抗张指数为11.5 N·m/g,耐破指数为0.581 k Pa·m~2/g,撕裂指数为1.69 m N·m~2/g。同时,对灵芝纤维的微观结构和纤维形态进行了初步分析和表征。以中药渣替代部分木质纤维或废纸浆用于造纸,具有良好的经济和环境价值。     

松柏醇葡萄糖苷用于提高纸张物理强度的研究

本文研究了在过氧化物酶的体系下利用木素前驱物松柏醇葡萄糖苷与果胶和葡苷聚糖的复合体来提高纸张的强度.生成的复合体由于有木素,在酶的作用下与纤维上的碳水化合物及残余木素聚合,从而将果胶与葡苷聚糖联接到纤维上,使得果胶-葡苷聚糖-DHP复合体与纤维接枝、缠绕和互穿,从而提高纸张的强度.经过处理后的纸张有明显的干强度提高,湿强度有很大的提高,湿抗张指数从2.13 N·m/g提高到4.53 N·m/g,提高了112.7%.从处理后的浆的红外谱图及核磁谱图的分析表明松柏醇葡萄糖苷在纤维表面生成了DHP-碳水化合物复合体,DHP结构单元之间主要通过β-O-4、β-β和β-5方式相连接;DHP与碳水化合物之间主要是通过苯甲酯键和苯甲醚键相连的.     

打浆度和纤维配比对液体包装纸板面层纤维基片性能的影响

利用液体包装纸板的实际生产工艺,探讨了不同打浆度和纤维配比对液体包装纸板面层纤维基片抗张指数、撕裂指数、耐破指数、挺度、松厚度和内结合强度的影响,并通过压痕测试研究了其在加工应用上的适应性。结果表明,在改善液体包装纸板面层纤维基片强度性能上,优化打浆工艺比增加针叶木浆配比效果更好,针叶木浆/阔叶木浆配比为1∶1,打浆度22°SR时撕裂指数最大为13.4 mN·m~2/g;打浆度25°SR时挺度最大为85.9 mN·m;打浆度29°SR时耐破指数和抗张指数最大分别为5.82 kPa·m~2/g和68.2 N·m/g,此条件下压痕测试数据和效果表现佳。     

改性纤维的制备及其对纸张性能的影响

通过对不同的纤维原料进行改性,并研究了不同纤维改性后对成纸的性能影响。结果表明,不同纤维经过改性后添加到纸浆中抄纸,对成纸的强度都是有利的。对硫酸盐浆进行部分改性后添加5%到浆料中,抗张指数可从38.28N·m·g-1提高到47.21N·m·g-1,撕裂指数增加10.92%;对高得率浆进行改性后添加1.5%到纸浆中,纸张内结合强度从49.41J·m-2提高到了55.30J·m-2,抗张指数增加48.06%;对木屑纤维改性后添加1.5%到OCC纸浆中,抗张指数从18.89N·m·g-1增加到27.55N·m·g-1,环压强度指数增加13.99%。     

环保型高固含量湿强剂CPAE的合成及应用

以硅烷偶联剂KH-560对传统湿强剂聚酰胺多胺环氧氯丙烷(PAE)树脂进行化学改性,并对上述反应体系进行了有效的后处理以降低有机氯含量,制备了一种新型环保型高固含量湿强剂CPAE树脂。与未改性PAE相比,使用CPAE树脂后,在1.0%用量下抄纸,纸张湿强度明显提高,抗张指数从41.0 N·m/g增加到51.3 N·m/g,提高了25.1%;湿抗张指数从8.11 N·m/g增加到15.5 N·m/g,提高了91.1%;抗张强度保留率从19.8%增加到30.2%,提高了52.5%。与市售PAE相比,CPAE固含量从12.5%提高到30%;CPAE经有机胺进行后处理后,有机氯含量由市售PAE的5%降低到0.5%以下。     

纸浆物理强度与纤维表面木素含量关系的探讨

通过酸析木素的方法在漂白硫酸盐浆纤维表面沉积木素,探讨了纸浆纤维表面木素含量对纸浆强度性能的影响.研究结果表明,随着硫酸盐木素溶液pH值的降低,木素在纸浆纤维表面的沉积吸附量增加;经过打浆作用的纸浆纤维暴露出更多的表面,能够吸附更多的木素;纸浆纤维表面木素含量与纸浆的抗张指数、耐破指数呈负的线性相关性,相关方程式分别为y=-1.23x +56.9(R=0.99)和y=-0.104x +4.62(R=0.96);增加纤维表面木素含量会降低纸浆纤维间的结合强度.     

OCC浆回用过程中化学组分变化及纤维损伤的表征

对回用过程中废旧瓦楞纸板(OCC)浆的化学组分变化进行研究,以纤维角质化指数(损伤变量Dh)和光散射系数S的变化对回用纤维的损伤程度进行表征,并借助扫描电镜对回用纤维的表面形貌进行分析。结果表明,随着回用次数的增加,OCC浆的灰分、热水抽出物、苯醇抽出物及1%NaOH抽出物含量逐步降低,而综纤维素和木素的变化幅度较小。另外,多次回用使得纤维损伤变量Dh和光散射系数S明显增大,成纸抗张强度随纤维损伤的变化规律呈线性关系。SEM分析结果显示,随着回用次数的增加,纤维表面变得越来越粗糙,出现很多裂痕,表明OCC纤维经不断回用后发生了纤维角质化。     

黏胶纤维在高透气度滤棒成型纸上的应用研究

研究了黏胶纤维替代部分针叶木浆生产高透气度滤棒成型纸的可行性,分析了黏胶纤维对滤棒成型纸透气度及抗张强度的影响。结果表明,在实验室条件下,针叶木浆打浆度22°SR,黏胶纤维用量40%,增强剂用量1%,滤棒成型纸手抄片可获得较高的透气度和抗张强度,透气度达到3000 CU,抗张指数达到50 N·m/g。     

Alkali treatment on nettle fibers

This work deals with alkali treatment on nettle fibers. The first part of this work examines structure and properties of alkali-treated nettle fibers, while the second part reports on optimization of alkali treatment to improve tensile properties of nettle fibers. In this part, the alkali-treated nettle fibers were examined for their chemical, structural, physical, and mechanical characteristics and compared to untreated fibers. The alkali treatment appeared to remove lignin from the fiber, thereby resulting in increase in its crystallinity, improvement in its appearance, and decrease in its width and linear density. The untreated fiber was quite strong but less flexible and less extensible. A mild alkali treatment resulted in increase in tensile strength and elongation at break, without much changing initial modulus. On the other hand, a severe alkali treatment resulted in reduction in fiber strength as well as initial modulus without much change in elongation at break.     

Morphology,Structure, and Mechanical Properties of Natural Cellulose Fiber from Mendong Grass (Fimbristylis globulosa)

This study was to investigate the morphology, structure, and chemical properties of the Mendong fibers extracted from Mendong grass (Fimbristylis globulosa) in the form of raw and treated fiber by alkali-included chemical content and functional group and to evaluate the strength and properties of Mendong fibers compared with other natural fibers. These studies explore the chemical properties of the fiber including fiber composition and functional group by FTIR, mechanical properties of fiber, and the structural and morphological analysis of the fiber using SEM and XRD. The results showed that the chemical contents of Mendong fibers were 72.14% cellulose, 20.2% hemicellulose, 3.44% lignin, 4.2% extractive, and moisture of 4.2%–5.2%. Mechanical properties of the fiber were a strong character with tensile strength of 452 MPa, and modulus of 17 GPa. The structural properties of Mendong fiber such as crystallinity, crystalline index, microfibril angle, and crystalline size were 70.17% and 58.6%, 22.9°, and 14.3 nm, respectively. This fiber has competitive advantages compared with other natural fibers and can be developed further as a potential reinforcement of polymer matrix composites.     

黄麻伴生物含量及其对理化性能的影响

为研究黄麻伴生物含量对其断裂强度、断裂模量、甲醛用量的影响,采用称重法测试了麻纤维的化学成分含量,采用单纤维拉伸法测试了麻纤维的断裂强度和模量,采用紫外分光光度计法测试了麻纤维的甲醇用量。经分析认为黄麻纤维的伴生物含量与其理化性能所组成的系统为灰色系统,并对此系统采用灰关联法进行分析。结果表明：黄麻脂蜡质含量对麻纤维的断裂强度影响比较大,关联度为分别为 0.680;黄麻木质素含量对其模量和甲醛用量影响最大,关联度分别为 0.733和0.723。     

环保型麻地膜的试制

 将非织造布制造工艺与特有的浸渍等后整理工艺相结合,以苎麻、黄麻等麻类纤维为主要试制原料,研究成网方法、固结方法、拒水整理等对环保型麻地膜的影响。结果表明,采用梳理成网与气流成网相结合的成网工艺、使用丙烯酸脂胶乳或醋酸乙烯胶乳为固结剂的化学固结方法,产品表面浸渍有机氟防水剂等组合工艺,试制的麻地膜产品面密度为30~50 g/m2、抗拉强力为629~1 532 N.m、顶破强力为81~203 N、撕破强力为56~82 N、渗透系数为7.79×10-4~1.76×10-3,产品力学性能指标满足使用要求。     

Assessment of Ichu Fibers Extraction and Their Use as Reinforcement in Composite Materials

ABSTRACT

This paper describes the research conducted to develop an optimal methodology to extract useful fibers from the “Ichu” grasses which can be used as reinforcement of polyester resin. Laminates were manufactured and their flexural properties were characterized as well as the optimal fiber properties. Results show that for this kind of materials, the mechanical and retting treatments are insufficient to remove lignin from the raw material state; on the other hand, alkali treatments are considerably effective. Laminates transverse strength shows an improvement (up to 30 MPa) when the alkali treatment time increases. Longitudinal strength and modulus present values around ~144 MPa and ~8.8 GPa respectively with fiber volume fraction around 0.38.     

Characterization of a New Lignocellulosic Fiber from Brazil: Imperata brasiliensis (Brazilian Satintail) as an Alternative Source for Nanocellulose Extraction

The chemical, physical and thermal properties of a new lignocellulosic fiber from Brazil (Imperata brasiliensis) were examined by SEM, chemical composition, XRD, FTIR, and TGA. Fibers were analyzed aiming to compare the properties of its new natural resource with other lignocellulosic fibers used as a source of nanocellulose extraction. Microscopy analysis demonstrated that the bundle of fibers presented a variety of size and shapes, ranging between 25 and 500 µm, while a single fiber has a diameter of 5 µm. The chemical composition showed the presence of 37.7% of cellulose, 35% of hemicellulose and 14.3% of lignin. The total crystallinity index (CI) calculated using Segal method was of 36.6%. By TGA, it was possible to identify the degradation step of each primary component of lignocellulosic fiber and to observe that the onset degradation temperature was 157°C. With the results of ATR-FTIR technique, it was possible to estimate the CI, and the results exhibited good agreement with that calculated by XRD. Finally it was possible to conclude that fibers obtained from Imperata brasiliensis are suitable to be used as a resource for nanocellulose obtainment since presents almost the same properties of other lignocellulosic fibers successfully used in literature for nanocellulose extraction.