注意:请所有相关的材料安全数据表。用于试验的化学品是有毒和致癌性。使用个人防护装备（护目镜，手套，实验室外套，全长裤，封闭趾鞋）。 1.设置为测试<ol><li> 样品的制备 <ol><li>垂直切割织物带沿方向的纤维（以测试芯吸在纤维方向）。 注:该带的长度，以获得一个限定的纤维体积比来计算。为碳织物，以获得V F = 40％时，条带的长度为150毫米。对未处理和处理过的亚麻，达到同样的V F，长度为365毫米。每个条带的宽度将等于样本保持器，其为20毫米（ 图1）的高度。 </li><li>滚动条紧紧地允许其插入成R &lt;的圆柱形样品架/ EM&gt; = 6毫米。 </li><li>添加样品架和样品增强件之间的薄纸过滤器（为了抑制样品支架上的芯吸作用）。过滤纸的最大厚度为0.1毫米。 </li><li>插入样品进入气缸及螺杆在底部上方的钻孔盖和活塞，以确保压缩。 </li><li>夹紧样品架与织物的张力。 </li></ol></li><li> 液体制剂 <ol><li>填充容器与液体检验，并将其放置到张力的特定容器。利用容器由硼硅酸玻璃中，用直径为70毫米。 </li><li>对于第一次测试（步骤2.1）中，使用正己烷。对于第二个测试（步骤2.3），使用的水。保证在容器中的液体达到至少12毫米的高度。 </li></ol></li><li> 实验参数 <ol><li>表面检测阈值设置为8毫克和transla以0.5毫米/秒的液体容器用于检测液体的灰速度。 </li></ol></li></ol> 2.吸湿排汗测试注:样品的制备和张力参数的设置后，排汗测试可以启动。液体容器中，直至所述液体与所述样品保持器接触向上移动。然后，液体上升到样品保持器，并且所述张力测量随时间的平方液体质量增益。数据由设置有张力的软件记录。那么大众对时间的一种曲线可视化每个灯芯测试。 <ol><li> 确定几何系数最初的测试: <ol><li>使用完全润湿液体（的量，接触角为0°），如正 - 己烷。 </li><li>停止芯吸试验时的可视化曲线达到恒定值。这表明液体到达样品架的顶部，因而，该芯吸完毕。 </li><li&gt;适合芯吸曲线（ 米2（t））的与沃什伯恩方程的线性趋势: <img alt="公式3" src="/files/ftp_upload/55059/image003.jpg" /> （3） 由于前进接触角假设为0°，用正己烷，从线性拟合的斜率，确定几何常数，C（毫米5）。 注:所有测试均在20℃的标准条件下进行。在温度变化将修改液体的表面张力和结果。 </li></ol></li><li> 样本保持器的清洗为以下测试 注:除去湿织物后，将样品保持器必须被完全清洁，以防止在下面的测量中的误差。 <ol><li>浸入样品架与sulfochromic酸（重铬酸钾的饱和溶液的50％，浓硫酸的50％），持续30秒的容器中。 </li><li>用蒸馏水冲洗，并然后擦干。 </li></ol></li><li> 第二测试用于确定表观前进接触角 <ol><li>使用的量，前进接触角必须用一个新的，一致的，和干燥织物样品测定对象的液体。 注:水，以便验证该方法中使用。 </li><li>停止芯吸试验时的可视化曲线达到恒定值。这表明液体到达样品架的顶部，该毛细上升完毕。 </li><li>适合芯吸曲线（ 米2（t））的同Washburn等式（等式3）的线性部分中，由于常量，C是已知由于第一测试（步骤2.1），以线性拟合确定所述斜率前进接触角θ 一 （°）。 注:所有测试均在20℃的标准条件下进行。在温度变化将修改液体的表面张力和结果。 </li></ol></LI&gt; <li> 的液体重量贡献的评估由于样品架 注:张力，作为一个微量天平，测定的液体的总质量，包括在所述织物的液体上升和外部弯液面上的样品架的贡献，并在过滤器中的毛细作用。这些捐款必须隔离。 <ol><li>把滤纸的相同量的在步骤1.1.3用于进入样本保持器，并重复步骤2.1.1-2.1.2。 </li><li>减去从记录在步骤2.1.3中的数据获得的恒定值（M 2）和换档曲线来评估几何常数，C的正确评估。 </li><li>填写样品架只用滤纸并重复步骤2.3.1-2.3.2。 </li><li>减去从记录在步骤2.3.3中的数据获得的恒定值（M 2）和换档曲线来评估前进接触角的正确的评价，θA。 </li></ol></li>
</ol>

<ol>
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The authors have nothing to disclose.

在协议中的关键步骤涉及样品的准备。首先，在轧制采样必须紧，以使均匀的纤维体积比的假设。如果在样品中的紧密度梯度，Washburn等式5,6不能用于以适合芯吸的曲线。另外，织物和样品架之间的边界条件是难以控制。因此，过滤器纸（1.1.3）也必须仔细插入样品架8。 该技术的一些修改可以使进行分析，以评估在毛细管压力8各向异性影响芯吸的其他方向。例如，一个可以切条沿着纤维的方向，以垂直于纤维（在加强平面）测试的方向上的芯吸;或者可以削减盘Ø圆柱形样品架半径F的增强材料和它们堆叠，以测试在横向芯吸。 但是，该过程是由沃什伯恩假说5限定。另外，该方法是在样本大小方面的限制，因为既不更长也不大样品可以当前处理。此必须对某些类型的织造，如较大的丝束来解决。 这种方法是目前唯一一个允许自发浸渍过程中毛细管压力的决心。该参数是用于复合材料制造，并在由液体复合成型工艺制造工业的复合材料部件的空隙形成的模拟主重要性。 关键步骤可以具有用于进一步的应用还有待提高。样品架的修改将为了移动所有的实际边界进行。另一个未来的应用是到u瑟以确定与树脂的毛细压力，这是LCM过程的最终目的的过程。

期间在液体复合成型（LSM）工艺纤维增强材料的浸渍，树脂的流动由压力梯度驱动。毛细效应有可与压力梯度，竞争取决于工艺参数的附加效果。它们对过程的影响因而具有待评估1,2。这可以通过定义一个明显的毛细压力P 帽 ，修改初始压力梯度3来完成。此参数可随后插入数字模型，以便在流程模拟流动，并准确地预测空洞形成4。 由液体（芯吸）织物的自发浸渍可以通过Washburn等式5进行说明。最初，Washburn等式中描述的液体的毛细上升的管。这个方程WA记者随后延长多孔结构，如纤维增强材料时，可以近似为一个毛细管网络。考虑具有半径R，填充有多孔介质的圆柱形样本保持器，Washburn等式中的平方质量增量（ 平方米（t））的随时间的形式被修改，如下6: <img alt="式（1）" src="/files/ftp_upload/55059/image001.jpg" /> （1） 其中，c是占迂曲的参数中，R是平均孔隙半径，ε= 1-V f是孔隙率（Ⅴf为纤维体积比）。在方括号的所有参数涉及在多孔介质的形态和结构，并且它们可以被合并到一个常数，C被称为"几何多孔介质因子"。其他参数表达毛细在介质和液体之间的相互作用（通过ρ，η依赖性，γL， 这分别是密度，粘度和表面的液体的张力，并且通过θA，表观前进接触角）。 平行地，通过多孔介质的流动通常与公知的达西定律7，其涉及的等效流体速度vð建模，通过介质，K和液体的粘度，的渗透性的压降η 。这个等式还允许质量增益在一段平方根，因此，供两个方程之间的等价的表达。从沃什伯恩方程和达西定律之间的等价，毛细管压力，然后定义如下8: （2） 这里，主要的焦点是描述的实验程序来测量的几何因素和单向织物表观前进接触角，以确定所述毛细管压力的目的。此方法依赖于使用张力进行芯吸测试（图1）。张力计是具有10微克的分辨率测量的液体物料或周围形成固体弯月面或上升纤维状介质微量天平。芯吸试验进行了考虑的一维表征（沿纤维方向）8,9。用于验证程序准单向织物是在一个V F = 40％的碳的单向（UD）织物。一旦方法进行了验证，亚麻织物提交热处理吨帽子修改纤维6的润湿行为，并分别具有不同的纤维体积比为未处理和处理亚麻织物进行芯吸测试（从30％至40％）。以确定形态和润湿参数，至少两个芯吸测试是强制性的:第一个具有完全润湿液体，如正己烷，以确定C（式1），而第二个与感兴趣的液体，以确定明显的前进接触角，一旦启用C是已知的。在第一种方法中，将水用于评估过程。 这种方法可以适用于不同的面料和液体，允许材料几何（面料的形态），孔隙率（不同纤维体积比），和粘度和在毛细管浸渍现象的液体表面张力的影响的评估。很明显，根据本沃什伯恩理论（等式1）中的步骤可以仅当芯吸立方米被采用rves（ 平方米（t））的由张力记录，具有线性的趋势。这意味着在公式1的参数必须在整个芯吸过程保持不变。如果不是这种情况下，作为在水中的亚麻增强，因为纤维离岗肿胀10，11，Washburn等式应修改成包括以描述的测试正确9肿胀的效果。处理过的织物被认为是对水吸附9不太敏感。几何因素和润湿参数可从线性拟合来测定，允许毛细管压力P 帽的计算。

<table><tbody><tr><td>Carbon UD fabrics</td><td>Hexcel&amp;nbsp;</td><td>48580</td><td></td></tr><tr><td>Flax UD fabrics</td><td>Libeco</td><td>FLAXDRY UD 180</td><td></td></tr><tr><td>n-Hexane</td><td>Sigma Aldrich</td><td></td><td></td></tr><tr><td>Sulfochromic acid</td><td>home made</td><td></td><td>toxic and corrosive</td></tr><tr><td>Filter paper</td><td>Dataphysic</td><td>FP11</td><td></td></tr><tr><td>Tensiometer</td><td>Dataphysic</td><td>DCAT11</td><td></td></tr></tbody></table>

wicking tests for unidirectional fabrics: measurements of capillary parameters to evaluate capillary pressure in liquid composite molding processes

期间在液体复合成型（LCM）的处理的纤维补强的浸渍，毛细管效应有，以便识别在复合材料部件其上形成空隙的影响可以理解。在由Washburn等式描述的纤维状介质芯吸被视为等同于根据达西定律的毛细压力的作用下的流动。为排汗的特性实验测试使用的碳和亚麻纤维加固进行。准单向织物然后通过一个张力的手段来确定沿光纤方向的形态和润湿参数测试。该过程被证明是有前途的，当织物的形态是毛细管芯吸过程中保持不变。在碳织物的情况下，该毛细管压力可以计算出来。亚麻纤维对水分的吸附敏感，并在水中溶胀。这种现象，必须考虑以评估润湿参数。一世n阶使纤维吸水较不敏感，热处理于亚麻增援进行。这种治疗方法增强纤维的形态稳定性和在水中的防止肿胀。结果表明，处理过的织物具有类似于在碳织物发现，允许毛细管压力的确定的线性芯吸的趋势。

与张力为碳和未处理的和处理过的亚麻织物芯吸得到期间增重的曲线示于图2和3。所有曲线的外部弯液面的两个权重的减法后示出由于样品保持器和过滤纸和被移位到零。 有可能从图2的曲线，与正己烷和水两者，公式1与实验芯吸的线性拟合是公实现，如果织物中的样品架正确插入到观察。使用滤纸的是强制性的，以保证测量的可重复性。这使得可以设定恒定，C 然后计算表观前进接触角，θA。曲线达到由该样品的高度给定一个渐近平衡本身，这被限制到20毫米，以确保在毛细管驱动流。平衡重是由于由测试液体的多孔介质的饱和。因此它与纤维体积比和样品架内体积（ 即，孔隙率，ε）。与派生常数，C和表观前进接触角，θA（ 表1），有可能确定毛细压力P 帽 ，沿单向碳织物的纤维方向。 像中的碳织物，对未处理和处理过的亚麻增强芯吸试验进行。 图3（左）显示了五个测试为正己烷获得的实验曲线。观察到两个处理和未处理亚麻织物的线性趋势，允许的几何因子的确定。只观察到轻微的差别未处理的和处理过的织物之间，表明曲折与治疗最终减少，但没有表现出形态的一个显著修饰。显示在图3（右）治疗对亚麻增强的显著效果。很明显，一个线性拟合是可能在处理过的织物，而未经处理的那些清楚地表明一个非线性趋势。以上为三种增强件5次试验的平均结果示于表1中。因此这将是可能的，织物渗透率的测量后，用等式2为仅处理过的织物的等效毛细管压力来计算。在芯吸差异是由于与水的敏感性诱导亚麻纤维的溶胀。芯吸过程中的天然纤维的溶胀导致在纤维体积比，这导致要更慢达到平衡重量的增加。它也诱导较小的平衡重量由于在孔隙度的减少。该capill元上涨已经发现是切碎，治疗亚麻纱快;这样的结果是一致的。因此6。处理使得纤维水吸附9不太敏感，这可以因此在芯吸对未处理和处理过的织物解释的差异。然后将改性沃什伯恩方程包括肿胀的效果被用于适合在亚麻织物芯吸的实验数据，允许确定毛细管压力，P 帽 9。 <img alt="图1" src="/files/ftp_upload/55059/55059fig1.jpg" /> 图1:张力（左）和圆柱形样品架（右）的方案8。此方案表示张力设置（左）和描绘了移动容器和称重装置，它随着时间的推移记录样品重量。样品架被显示在右边巴该计划的室温。活塞和钻帽确保织物的压实可以看出。 <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55059/55059fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/55059/55059fig2.jpg" /> 图2:在x方向的两个实验测试沃什伯恩配合，用正己烷（左）和水（右）。该测试是指碳面料V F = 40％8。该图的目的是要表明，毛细管芯吸图的第一部分是线性的，标绘相对于时间的平方质量增益。它也表明，这是验证对每个测试液体。 <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55059/55059fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 在V F = 40％9与正己烷（左）和水（右）中得到了未处理和处理过的亚麻织物芯吸曲线:图3。这些图清楚地表明，有未处理和处理亚麻织物之间有大的差别。而线性拟合可以用正己烷来实现这两个织物，这是不可能的，用水未处理亚麻。这是由于在亚麻纤维的溶胀。 <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55059/55059fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> 织物类型 </td><td> CR（微米） </td><td> θA（°） </td></tr><tr><td>碳UD＆＃160; </td><td> 12.1±1.5 </td><td> 74.8±2.3 </td></tr><tr><td>未经处理的亚麻UD </td><td> 12.2±1.4 </td><td> ？ </td></tr><tr><td>处理亚麻UD </td><td> 15.3±1.3 </td><td> 72.1±1.8 </td></tr></tbody></table> 表1:几何产物和表观前进接触角在碳上和在未处理和处理亚麻织物的平均测量值。此表列出了在五个测试的每个织物，从实验的曲线图与沃什伯恩方程的线性拟合（ 米2（t））的派生的平均值。

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Wicking Tests for Unidirectional Fabrics: Measurements of Capillary Parameters to Evaluate Capillary Pressure in Liquid Composite Molding Processes

实验方法测量几何参数和说明毛细血管单向合成和天然面料吸湿排汗，提出了推进表观接触角。这些参数是强制性的，必须考虑到对液体复合成型（LCM）应用的毛细压力的确定。

吸湿排汗试验单向织物:毛细管参数的标准评价在液体复合成型工艺毛细管压力

During impregnation of a fibrous reinforcement in liquid composite molding (LCM) processes, capillary effects have to be understood in order to identify ...

wicking-tests-for-unidirectional-fabrics-measurements-capillary

Nanyang Technological University

Research

Education

JoVE Core

JoVE Journal

Civil Engineering

Engineering

Unit 1

Fluid Properties

SCIENTISTS IN ACTION

8.7K 次观看.  Mines Saint-Étienne. 实验方法测量几何参数和说明毛细血管单向合成和天然面料吸湿排汗，提出了推进表观接触角。这些参数是强制性的，必须考虑到对液体复合成型（LCM）应用的毛细压力的确定。 

视频: Wicking Tests for Unidirectional Fabrics: Measurements of Capillary Parameters to Evaluate Capillary Pressure in Liquid Composite Molding Processes

A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli

The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs and condition-based maintenance. These materials are adopted in a wide range of engineering applications, from aircraft and ship structures, to bridges, wind turbine blades, biomaterials and biomedical implants. Polymers are viscoelastic materials, and their response may be highly nonlinear and thus make it challenging to predict and monitor their in-service performance. The laboratory-scale testing platform presented herein assists the investigation of the influence of concurrent mechanical loadings and environmental conditions on these materials. The platform was designed to be low-cost and user-friendly. Its chemically resistant materials make the platform adaptable to studies of chemical degradation due to in-service exposure to fluids. An example of experiment was conducted at RT on closed-cell polyurethane foam samples loaded with a weight corresponding to ~50% of their ultimate static and dry load. Results show that the testing apparatus is appropriate for these studies. Results also highlight the larger vulnerability of the polymer under concurrent loading, based on the higher mid-point displacements and lower residual failure loads. Recommendations are made for additional improvements to the testing apparatus.

The durability of polymers and fiber-reinforced polymer composites in service is a critical aspect for their designs and condition-based maintenance. We present a novel low-cost laboratory testing platform for the investigation of the influence of concurrent mechanical and environmental loadings, and may help design more efficient yet safer composite structures.

一个测试平台为聚合物的耐久性研究，并在同期Hygrothermo机械刺激纤维增强聚合物复合材料

The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs ...

科研

工程学

Experimental Implementation of a New Composite Fabrication Method: Exposing Bare Fibers on the Composite Surface by the Soft Layer Method

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional component that should have high electrical conductivity, high mechanical properties, and high productivity.
In this regard, a carbon fiber/epoxy resin composite can be an ideal material to replace the conventional graphite bipolar plate, which often leads to the catastrophic failure of the entire system because of its inherent brittleness. Though the carbon/epoxy composite has high mechanical properties and is easy to manufacture, the electrical conductivity in the through-thickness direction is poor because of the resin-rich layer that forms on its surface. Therefore, an expanded graphite coating was adopted to solve the electrical conductivity issue. However, the expanded graphite coating not only increases the manufacturing costs but also has poor mechanical properties.
In this study, a method to expose fibers on the composite surface is demonstrated. There are currently many methods that can expose fibers by surface treatment after the fabrication of the composite. This new method, however, does not require surface treatment because the fibers are exposed during the manufacture of the composite. By exposing bare carbon fibers on the surface, the electrical conductivity and mechanical strength of the composite are increased drastically.

A protocol to expose bare fibers on the composite surface by eliminating resin rich area is presented. The fibers are exposed during fabrication of the composites, not by the post surface treatment. The exposed carbon composites exhibit high electrical conductivity in the through-thickness direction and high mechanical property.

一种新的复合制备方法的实验实现: 用软层法对复合材料表面裸露纤维进行曝光

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional ...

Deposition of Porous Sorbents on Fabric Supports

A microwave deposition technique for silanes, previously described for production of oleophobic fabrics, is adapted to provide a fabric support material that can be subsequently treated by dip coating. Dip coating with a sol preparation provides a supported porous layer on the fabric. In this case, the porous layer is a porphyrin functionalized sorbent system based on a powdered material that has been demonstrated previously for the capture and conversion of phosgene. A representative coating is applied to cotton fabric at a loading level of 10 mg/g. This coating has minimal impact on water vapor transport through the fabric (93% of the support fabric rate) while significantly reducing transport of 2-chloroethyl ethyl sulfide (CEES) through the material (7% of support fabric rate). The described approaches are suitable for use with other fabrics providing amine and hydroxyl groups for modification and can be used in combination with other sol preparations to produce varying functionality.

This report details a microwave-initiated approach for deposition of porphyrin functionalized porous organosilicate sorbents on a cotton fabric and demonstrates reduction in 2-chloroethyl ethyl sulfide (CEES) transport through the fabric resulting from this treatment.

织物支架上多孔吸附剂的沉积

A microwave deposition technique for silanes, previously described for production of oleophobic fabrics, is adapted to provide a fabric support material ...

化学

Magnet Assisted Composite Manufacturing: A Flexible New Technique for Achieving High Consolidation Pressure in Vacuum Bag/Lay-Up Processes

This work demonstrates a protocol to improve the quality of composite laminates fabricated by wet lay-up vacuum bag processes using the recently developed magnet assisted composite manufacturing (MACM) technique. In this technique, permanent magnets are utilized to apply a sufficiently high consolidation pressure during the curing stage. To enhance the intensity of the magnetic field, and thus, to increase the magnetic compaction pressure, the magnets are placed on a magnetic top plate. First, the entire procedure of preparing the composite lay-up on a magnetic bottom steel plate using the conventional wet lay-up vacuum bag process is described. Second, placement of a set of Neodymium-Iron-Boron permanent magnets, arranged in alternating polarity, on the vacuum bag is illustrated. Next, the experimental procedures to measure the magnetic compaction pressure and volume fractions of the composite constituents are presented. Finally, methods used to characterize microstructure and mechanical properties of composite laminates are discussed in detail. The results prove the effectiveness of the MACM method in improving the quality of wet lay-up vacuum bag laminates. This method does not require large capital investment for tooling or equipment and can also be used to consolidate geometrically complex composite parts by placing the magnets on a matching top mold positioned on the vacuum bag.

A new technique for applying consolidation pressure on the vacuum bag lay-up to fabricate composite laminates is described. The goal of this protocol is to develop a simple, cost-effective technique to improve the quality of laminates fabricated by the wet lay-up vacuum bag method.

磁铁辅助复合制造: 真空袋/糊化过程中实现高固结压力的一种柔性新技术

This work demonstrates a protocol to improve the quality of composite laminates fabricated by wet lay-up vacuum bag processes using the recently developed ...

Scalable Stamp Printing and Fabrication of Hemiwicking Surfaces

Hemiwicking is a process where a fluid wets a patterned surface beyond its normal wetting length due to a combination of capillary action and imbibition. This wetting phenomenon is important in many technical fields ranging from physiology to aerospace engineering. Currently, several different techniques exist for fabricating hemiwicking structures. These conventional methods, however, are often time consuming and are difficult to scale-up for large areas or are difficult to customize for specific, nonhomogeneous patterning geometries. The presented protocol provides researchers with a simple, scalable, and cost-effective method for fabricating micro-patterned hemiwicking surfaces. The method fabricates wicking structures through the use of stamp printing, polydimethylsiloxane (PDMS) molding, and thin-film surface coatings. The protocol is demonstrated for hemiwicking with ethanol on PDMS micropillar arrays coated with a 70 nm thick aluminum thin-film.

A simple protocol is provided for the fabrication of hemiwicking structures of varying sizes, shapes, and materials. The protocol uses a combination of physical stamping, PDMS molding, and thin-film surface modifications via common materials deposition techniques.

可缩放邮票印刷及不堪砌面的制作

Hemiwicking is a process where a fluid wets a patterned surface beyond its normal wetting length due to a combination of capillary action and imbibition. ...

Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications

Superhydrophobic materials, with surfaces possessing permanent or metastable non-wetted states, are of interest for a number of biomedical and industrial applications. Here we describe how electrospinning or electrospraying a polymer mixture containing a biodegradable, biocompatible aliphatic polyester (e.g., polycaprolactone and poly(lactide-co-glycolide)), as the major component, doped with a hydrophobic copolymer composed of the polyester and a stearate-modified poly(glycerol carbonate) affords a superhydrophobic biomaterial. The fabrication techniques of electrospinning or electrospraying provide the enhanced surface roughness and porosity on and within the fibers or the particles, respectively. The use of a low surface energy copolymer dopant that blends with the polyester and can be stably electrospun or electrosprayed affords these superhydrophobic materials. Important parameters such as fiber size, copolymer dopant composition and/or concentration, and their effects on wettability are discussed. This combination of polymer chemistry and process engineering affords a versatile approach to develop application-specific materials using scalable techniques, which are likely generalizable to a wider class of polymers for a variety of applications.

Two- and three-dimensional superhydrophobic polymeric materials are prepared by electrospinning or electrospraying biodegradable polymers blended with a lower surface energy polymer of similar composition.

制造超疏水高分子材料生物医学应用

Superhydrophobic materials, with surfaces possessing permanent or metastable non-wetted states, are of interest for a number of biomedical and industrial ...

生物工程

Cutting Procedures, Tensile Testing, and Ageing of Flexible Unidirectional Composite Laminates

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, where the yarns in each layer are oriented parallel to each other and held in place using binder resins and thin polymer films. The armor is constructed by stacking the unidirectional layers in different orientations. To date, only very preliminary work has been performed to characterize the ageing of the binder resins used in unidirectional laminates and the effects on their performance. For example, during the development of the conditioning protocol used in the National Institute of Justice Standard-0101.06, UD laminates showed visual signs of delamination and reductions in V50, which is the velocity at which half of the projectiles are expected to perforate the armor, after ageing. A better understanding of the material property changes in UD laminates is necessary to comprehend the long-term performance of armors constructed from these materials. There are no current standards recommended for mechanically interrogating unidirectional (UD) laminate materials. This study explores methods and best practices for accurately testing the mechanical properties of these materials and proposes a new test methodology for these materials. Best practices for ageing these materials are also described.

The goal of the study was to develop protocols to prepare consistent specimens for accurate mechanical testing of high-strength aramid or ultra-high-molar-mass polyethylene-based flexible unidirectional composite laminate materials and to describe protocols for performing artificial ageing on these materials.

柔性单向复合层压板的切割程序、拉伸测试和老化

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, ...

Fabrication and Design of Wood-Based High-Performance Composites

Delignified densified wood is a new promising and sustainable material that possesses the potential to replace synthetic materials, such as glass fiber reinforced composites, due to its excellent mechanical properties. Delignified wood, however, is rather fragile in a wet state, which makes handling and shaping challenging. Here we present two fabrication processes, closed-mold densification and vacuum densification, to produce high-performance cellulose composites based on delignified wood, including an assessment of their advantages and limitations. Further, we suggest strategies for how the composites can be re-used or decomposed at the end-of-life cycle. Closed-mold densification has the advantage that no elaborate lab equipment is needed. Simple screw clamps or a press can be used for densification. We recommend this method for small parts with simple geometries and large radii of curvature. Vacuum densification in an open-mold process is suitable for larger objects and complex geometries, including small radii of curvature. Compared to the closed-mold process, the open-mold vacuum approach only needs the manufacture of a single mold cavity.

Delignified densified wood represents a new promising lightweight, high-performance and bio-based material with great potential to partially substitute natural fiber reinforced- or glass fiber reinforced composites in the future. We here present two versatile fabrication routes and demonstrate the possibility to create complex composite parts.

基于木材的高性能复合材料的制造与设计

Delignified densified wood is a new promising and sustainable material that possesses the potential to replace synthetic materials, such as glass fiber ...

A Multi-Cue Bioreactor to Evaluate the Inflammatory and Regenerative Capacity of Biomaterials under Flow and Stretch

The use of resorbable biomaterials to induce regeneration directly in the body is an attractive strategy from a translational perspective. Such materials induce an inflammatory response upon implantation, which is the driver of subsequent resorption of the material and the regeneration of new tissue. This strategy, also known as in situ tissue engineering, is pursued to obtain cardiovascular replacements such as tissue-engineered vascular grafts. Both the inflammatory and the regenerative processes are determined by the local biomechanical cues on the scaffold (i.e., stretch and shear stress). Here, we describe in detail the use of a custom-developed bioreactor that uniquely enables the decoupling of stretch and shear stress on a tubular scaffold. This allows for the systematic and standardized evaluation of the inflammatory and regenerative capacity of tubular scaffolds under the influence of well-controlled mechanical loads, which we demonstrate on the basis of a dynamic co-culture experiment using human macrophages and myofibroblasts. The key practical steps in this approach&#8212;the construction and setting up of the bioreactor, preparation of the scaffolds and cell seeding, application and maintenance of stretch and shear flow, and sample harvesting for analysis&#8212;are discussed in detail.

The goal of this protocol is to execute a dynamic co-culture of human macrophages and myofibroblasts in tubular electrospun scaffolds to investigate material-driven tissue regeneration, using a bioreactor which enables the decoupling of shear stress and cyclic stretch.

评估流和拉伸下生物材料的炎症和再生能力的多奎生物反应器

The use of resorbable biomaterials to induce regeneration directly in the body is an attractive strategy from a translational perspective. Such materials ...

纤维复合材料层压板的制造和机械性能评估

Measuring the Mechanical Properties of Glass Fiber Reinforcement Polymer Composite Laminates Obtained by Different Fabrication Processes

The traditional wet hand lay-up process (WL) has been widely applied in the manufacturing of fiber composite laminates. However, due insufficiency in the forming pressure, the mass fraction of fiber is reduced and lots of air bubbles are trapped inside, resulting in low-quality laminates (low stiffness and strength). The wet hand lay-up/vacuum bag (WLVB) process for the fabrication of composite laminates is based on the traditional wet hand lay-up process, using a vacuum bag to remove air bubbles and provide pressure, and then carrying out the heating and curing process. 
Compared with the traditional hand lay-up process, laminates manufactured by the WLVB process show superior mechanical properties, including better strength and stiffness, higher fiber volume fraction, and lower void volume fraction, which are all benefits for composite laminates. This process is completely manual, and it is greatly influenced by the skills of the preparation personnel. Therefore, the products are prone to defects such as voids and uneven thickness, leading to unstable qualities and mechanical properties of the laminate. Hence, it is necessary to finely describe the WLVB process, finely control steps, and quantify material ratios, in order to ensure the mechanical properties of laminates. 
This paper describes the meticulous process of the WLVB process for preparing woven plain patterned glass fiber reinforcement composite laminates (GFRPs). The fiber volume content of laminates was calculated using the formula method, and the calculated results showed that the fiber volume content of WL laminates was 42.04%, while that of WLVB laminates was 57.82%, increasing by 15.78%. The mechanical properties of the laminates were characterized using tensile and impact tests. The experimental results revealed that with the WLVB process, the strength and modulus of the laminates were enhanced by 17.4% and 16.35%, respectively, and the specific absorbed energy was increased by 19.48%.

作者聚焦：使用湿法手糊/真空袋工艺提高纤维复合材料层压板质量 

This paper describes a fabrication process for fiber-reinforced polymer matrix composite laminates obtained using the wet hand lay-up/vacuum bag method.

测量通过不同制造工艺获得的玻璃纤维增强聚合物复合层压板的机械性能

The traditional wet hand lay-up process (WL) has been widely applied in the manufacturing of fiber composite laminates. However, due insufficiency in the ...