纳米铜再生纤维素纤维的开发及应用

以黏胶纤维的生产工艺流程和主要设备为基础,开发和生产纳米铜再生纤维素纤维。简要介绍纳米铜再生纤维素纤维的基本情况和工艺流程,重点对纳米铜再生纤维素纤维的生产方法进行介绍,包括纳米铜原料分析、黏胶制备技术和纺丝后整理技术。分析纳米铜再生纤维素纤维的形态结构、物理性能和抗菌性能,并简述该纤维的开发应用情况。纳米铜再生纤维素纤维的生产过程容易控制,成品质量较好,具有较好的产业化和市场推广前景。     

TiO_2/纤维素多孔三维材料的制备及其在染料分解中的应用研究

以微晶纤维素为原料,通过LiCl/DMAc体系对微晶纤维素进行溶解,然后采用不良溶剂诱导相分离的方法制备纤维素多孔三维材料。所得材料具有三维连通的多孔结构,且材料内部孔以介孔居多,具有密度小、孔隙率大等优点,能够作为复合材料的基质广泛应用。将TiO_2纳米颗粒与纤维素多孔三维材料复合制得TiO_2/纤维素多孔三维材料,所得材料中TiO_2纳米颗粒在三维空间内分布均匀。TiO_2/纤维素多孔三维材料在紫外光照射下对亚甲基蓝溶液具有优秀的光催化降解性能,且能够多次重复利用。     

氨基纳米纤维素的制备及其抗菌应用研究进展

良好的生物相容性和可降解性使纳米纤维素成为一种绿色材料,并广泛用于食品和化工等领域,将纳米纤维素进行氨基化改性得到的氨基纳米纤维素保留了纳米纤维素的优点,而且纤维表面的正电荷还增加了材料的抗菌性能,可应用于生物医药等领域。本文从纳米纤维素的制备入手,探讨了几类常见的纳米纤维素在制备方法和形貌尺寸等方面的特征和差异;重点介绍了纳米纤维素的氨基化改性方法,包括常用的氨基化试剂和改性工艺;最后综述了氨基纳米纤维素的抗菌机理和在抗菌材料中的应用。     

静电纺丝和炭化法制备纳米纤维素储能材料研究进展

为促进纳米纤维素材料在储能领域的应用,综述了以其为原料,采用静电纺丝和炭化技术以及2种方法结合制备用于电池和超级电容器等电极材料和隔膜材料的工艺。通过分析发现:静电纺纳米纤维素材料具有电化学性能优异、柔性较好等优点,可用作增强材料与导电材料复合使用;炭化处理纳米纤维素材料具有独特微孔结构,比表面积大等特点,其存在的形态主要有气凝胶、纳米纤维膜及薄膜等;重点分析了2种方法叠加制备纳米纤维素材料在储能领域应用中存在的问题;提出构建环保、形态结构多样的天然基材储能器件是未来的发展方向,指出静电纺丝和炭化制备纳米纤维素材料在柔性储能器件和小巧型移动端储能设备中具有较好应用前景。     

丝素蛋白多孔材料及其在组织工程领域的应用

讨论丝素蛋白纤维多孔材料、再生丝素蛋白多孔材料以及丝素蛋白非织造状纳米纤维多孔材料的制备方法和材料性能。认为丝素蛋白多孔材料具有合适的孔径结构和良好的生物相容性,多种组织或器官的细胞可在这些材料上黏附和增殖。综述丝素蛋白多孔材料作为一种优良的组织工程支架材料,在人工皮肤、骨、软骨、人工肌腱和韧带等组织工程领域的应用情况。     

纤维素静电纺丝及其难题

静电纺丝是一种常见的连续生产纳米级纤维(直径在几微米到几纳米)的技术。它是将纳米纤维制成各种结构形式,如非织造织物膜、取向纤维束及三维结构支架的最常用方法。这些材料由于其被提升的性能,可应用于工业用纺织品、医用纺织品、防护材料、储能设备、农业、电器、光学设备等特殊领域。纤维素作为一种来源丰富的生物可降解、生物相容聚合物,引起研究者们的强烈兴趣,纳米织物中纳米纤维素纤维的广阔前景也显示其应用广泛。研究涉及了纤维素静电纺丝的历史、近况及前景。     

静电纺丝多孔碳纳米纤维制备与应用研究进展

为更好地通过静电纺丝技术制备多孔碳纳米纤维,综述了近年来国内外静电纺丝技术实现工业化的可行性,静电纺丝制备多孔碳纳米纤维的方法、多孔结构类型以及多孔碳纳米纤维的应用等方面的最新进展。主要介绍了聚合物与聚合物共混以及聚合物与无机粒子共混静电纺丝多孔碳纳米纤维的2种方法的制备原理及所制得多孔碳纳米纤维的特点,并根据孔结构形状将多孔碳纳米纤维分为中空结构、介孔结构、多级孔结构和碳壳-蜂巢芯结构等类型。最后介绍了静电纺丝多孔碳纳米纤维在电化学、储氢、催化和吸附等领域的应用情况,并对未来多孔碳纳米纤维的发展前景进行了展望。     

可再生纳米纤维素纤维防弹衣

正1纳米纤维素纳米纤维素是一种来源于木质纤维的材料,强度极高,可与Kevlar纤维(质轻,可用于制造高强耐用材料)相媲美,可用于生产防弹衣。与Kevlar纤维及其他基于化石燃料的材料不同,纳米纤维素是可再生的。以前,纳米纤维素因生产过程能耗过高而无法商品化,然而最近研究森林原材料的Innventia AB研     

静电纺多级结构空气过滤材料的研究进展

为促进静电纺纳米纤维在空气过滤领域中的应用,开发性能更加优异的新型纳米纤维空气过滤膜,以近年来国内外静电纺丝技术制备多级结构纳米空气过滤材料的相关研究为基础,综述了静电纺制备具有微纳米凸起、纳米蛛网、层层复合、多孔、刺状、树枝状及核壳等结构空气过滤材料的最新研究进展,分析和讨论了多级结构微纳米空气过滤材料的制备方法,指出了现有研究中存在的不足,并对未来的发展方向进行了总结和展望。认为多级结构可有效实现过滤材料高效率、低阻力、高强度、阻燃等的功能化,相较于传统的纳米纤维过滤材料具有更好的应用前景。     

日本纤维素纳米纤维纸杯明年上市

正据报道,旧本凸版印刷公司最近开发出利用纤维素纳米纤维(CNF)生产的具有氧气阻隔性的纸杯样品,此次推出的纸杯产品,着眼于纤维素纳米纤维的氧气阻隔性。由于将纤维素纳米纤维作为涂层附着于纸层表面,形成阻隔层,可以防止食品的氧化变质,属于环保型产品。由于该产、品兼有对异味的阻隔性,因此对食品还有保香和保鲜的功效。该公司推出的纤维素纳米纤维纸杯,     

Surface Modification and Characterization of PET Fibers

Improvement in synthetic fiber based composites is a hot topic in the material area.The incompatibility between the surfaces of synthetic fibers is a significant challenge due to fibers hydrophobic property.In this study,PET(polyethylene terephthalate) fibers based on low hydrophilic were slightly treated with NaOH or sodium dodecyl benzene sulfonate(SDBS).SEM images showed that there were some pits on the surface of PET fibers treated by NaOH,while PET fibers treated by SDBS became smoother.The peaks at 3725 cm~(-1) and 3628 cm~(-1) were generated for PET fibers treated by NaOH,which was attributed to—OH produced from the ester group hydrolysis,but no same peak is shown for the treated ones by SDBS.Meanwhile,the crystallinity indices of the treated PET fibers slightly decreased.Compared with original PET fibers,the formation of sheet made from PET fibers treated by NaOH became worse,but that from SDBS treated PET fibers became better.     

Occurrence of giant fibers in muscles from wild pigs native to the United States

The semimembranosus (SM) and triceps brachii (TB) muscles from wild pigs native to Florida. USA, were evaluated for histological characteristics. All three fiber types were present in both muscles in varying proportions, reflecting differences between tonic and phasic functioning muscles. Typical fiber arrangements were observed with red fibers grouped in clumps and surrounded by white fibers. The triceps brachii muscle contained a greater percentage of βR and αR fibers and possessed more giant fibers than the SM muscle which contained more αW fibers. The giant fibers observed resembled βR or αR fibers. The presence of hypertrophied fibers in the muscles from these wild pigs suggests that the 'giant fiber syndrome' is an intrinsic susceptibility for muscle fiber enlargement in these animals and not necessarily associated with breeding for muscularity since the carcasses from these pigs contained very small muscles and very little fat.     

Properties of Natural Fibers from the Abaxial Side of Fireweed (Gerbera delavayi) Leaf Blade for Manual Spinning

Natural plant fibers obtained from the abaxial side of fireweed (Gerbera delavayi) leaf blade were systematically studied. Fireweed fibers were manually dismantled from hot-bath-treated, refrigerated, or untreated leaves and evaluated for different properties. In terms of the collection method, treatment with hot bath exhibited the highest efficiency. As for chemical composition, that of raw (untreated) fireweed fibers was similar to that of cotton, except for wax content that was four times higher in fireweed fibers that in cotton fibers. Fireweed fiber generally exhibited low values of length (6.5 mm), fineness (0.5 dtex), tenacity (0.7 cN/dtex), density (0.9 g/cm³), and crystallinity (14.6%) but similar elongation at break and moisture regain to those of cotton. Furthermore, fireweed fibers showed a smooth surface, soft texture, and water impermeability. After hot-bath treatment, fibers showed 20% lower wax component but higher thermal stability than raw fibers. The small size hindered the fibers from achieving the desirable standard of spinning and weaving by modern machine, but these unique cellulose fibers can be used for manual textile application without any chemical treatment.     

Effect of different retting processes on yield and quality of banana pseudostem fiber

The main objective of this study is to develop a suitable technology to utilize banana pseudostem waste in an effective manner. The choice of a specific extraction method depends on the intended end uses of the fibers and hence different methods (mechanical, microbial, chemical, and enzymatic) were carried out to extract cellulosic fibers from Poovan variety and the chemical properties were investigated. The flexural and tensile properties of fibers were explored to analyze the suitability of fibers for different applications. Results obtained from these analyses confirmed that the tex value of chemical retted fiber was lesser than others. Scanning electron micrographs revealed that the surfaces of the chemically retted fibers were rougher than mechanically extracted fibers with an average diameter of 180 µm. The elemental composition of the chemical-treated banana pseudostem fibers was investigated by energy-dispersive X-ray analysis. Fourier transform infrared spectrum indicated the presence of similar functional groups in all the fiber samples.     

营盘出土棉纤维和现代棉纤维的对比分析

对新疆营盘出土14C 年代BP 845±40的草棉纤维通过光学显微镜、扫描电镜、红外光谱、X射线衍射等手段进行结构与性能测试,并与现代草棉纤维进行对比。以期建立古代棉纤维的数据资料,对古代棉纤维有更深入的了解。出土纤维的形态特征与现代草棉纤维接近,出土纤维的长度为18.3mm,线密度为0.27tex,显微镜观察转曲数为53次/cm。出土棉纤维的结晶度和横向晶粒尺寸并不低于现代草棉纤维,说明古代草棉纤维在新疆干燥的环境中保存较好。出土棉纤维的断裂强力与断裂伸长率较低,可能源于棉纤维素平均聚合度的下降。     

Corterra PTT纤维在纺织业中的应用前景

PTT纤维具有高弹性和手感柔软的特点 ,非常适合生产针织物和机织物。PTT短纤亦可生产非织造布 ,概述了PTT纤维在纺织行业的技术进展。     

Effects of freezing/thawing on the microstructure and the texture of smoked Atlantic salmon (Salmo salar)

The changes in microstructure and texture during smoking of fresh and frozen/thawed Atlantic salmon was studied in fish from three different origins; ocean-ranched Atlantic salmon (Salmo salar) from Iceland and two groups of farmed Atlantic salmon from northern and western Norway. The muscle fibers from the frozen and thawed fish shrank, and the extracellular space increased compared to the fresh muscle. The muscle fibers from salmon fillets with smaller fiber diameter shrank to a less extent than fibers from salmon material with a larger fiber diameter. After smoking the space between the fibers and the fiber shrinkage increased to a higher extent in the muscle from the salmon that were frozen prior to smoking than muscle smoked from fresh salmon. The initial cross-sectional area of the fibers was not found to be related to the yield during smoking.     

Influence of myosin heavy chain isoform expression and postmortem metabolism on the ATPase activity of muscle fibers

The objective of this study was to determine the effects of postmortem muscle pH and temperature declines on the actomyosin ATPase activity of muscle fibers expressing different MyHC isoforms. Using a quantitative histochemical procedure to determine ATPase activity, the maximum actomyosin ATPase activity was determined on individual fibers classified by MyHC expression. Samples were collected from the red (RST) and white (WST) semitendinosus muscles at 3 min and 24 h postmortem from electrically stimulated (ES) and control (NS) pork carcasses. In samples taken at 3 min postmortem, type I fibers had the lowest ATPase activity staining and type 2X and 2B had the highest activity staining, with type 2A fibers intermediate. Postmortem time and carcass treatment did not influence the ATPase activity staining of type I muscle fibers. ATPase activity staining of 2A fibers was lower (p<0.001) in 24 h samples than in 3 min samples from ES carcasses. In 3 min and NS-24 h samples, RST type 2A fibers had lower (p<0.05) activities than type 2A fibers from the WST. In type 2X fibers, ATPase activity staining decreased (p<0.01) from 3 min to 24 h postmortem in ES carcasses. This decrease was more severe in WST 2X fibers compared to RST 2X fibers. ATPase activity staining in type 2B fibers did not decrease from 3 min to 24 h postmortem in NS carcasses. In ES carcasses, activity staining of 2B fibers decreased (p<0.0001) with time postmortem. The results of the experiment indicate that fibers expressing fast MyHC isoforms have a higher ATPase activity early postmortem than slow muscle fibers but are more prone to inactivation by a rapid pH decline.     

Effects of drawing process on crimp formation-ability of side-by-side bicomponent filament yarns produced from recycled,fiber-grade and bottle-grade PET

In this study, side-by-side bicomponent filaments from recycled poly(ethylene) terephthalate (R-PET) from post-consumer bottles, fiber-grade PET (FG-PET) and bottle-grade PET (BG-PET) successfully were extruded. The bicomponent fibers in the forms of FG/R, BG/R and FG/BG were produced in a spinning machine and drawn by a thermal drawing process to improve their mechanical properties using draw ratios between ‘2.5 and 2.8’. The effects of conditions on the fiber structure, physical properties and crimp formation of resultant fibers were evaluated. The birefringence, shrinkage and mechanical properties, such as tensile strength and tensile modulus, increased and elongation at break decreased for the drawn fibers, and this was attributed to the fiber orientation. Distinct crimp formation was observed from drawn bicomponent fibers after thermal treatment. There were significant birefringence and shrinkage difference between two components in drawn bicomponent fibers caused to severe crimp formation.     

Finite Element Simulation of Fracture Mechanism of Fibrous Food

A finite element model was developed to simulate, analyze, and to understand the finer mechanical interactions between the growing crack and the constituent material properties of turmeric (Curcuma longa) as a model material. The parameters varied were residual stress state, fiber orientation, and interface bond. Fracture paths were predicted for fibers with respect to primary crack plane. Finite element model studies showed that within the parameters’ range selected the matrix residual compression caused cracks to deflect away from the fiber when the crack length was approximately 30 μm from the center of the fibers. The residual tension in the fibers promoted fibers to fracture when the cracks grew to within 10 μm from the fibers. The average specific fracture surface energy of turmeric was found to be 8.86 ± 1.74 J/m². Knowledge gained from such studies will be useful to predict a fracture mechanism in food materials and efficiently design food size reduction systems.