Name: experimental implementation of a new composite fabrication method: exposing bare fibers on the composite surface by the soft layer method
Uploaded: 2017-10-06T12:30:00.000+00:00
Duration: 6 min 26 s
Description: Watch this Scientific Journal Video about Experimental Implementation of a New Composite Fabrication Method: Exposing Bare Fibers on the Composite Surface by the Soft Layer Method at JoVE.com

この研究は、KAIST の気候変動研究ハブによって支えられた (付与号N11160012)、大手外国研究所募集プログラム韓国国立研究財団によって資金を供給科学省、ICT および将来計画 (グラント 2011-0030065 号)、大手人材トレーニング プログラム地域の新産業を通じて、国立研究財団の韓国 (NRF) とが出資、科学省、ICT 将来計画 (付与なし。NRF-2016H1D5A1910603)。彼らのサポートは大歓迎です。

1。 材料準備 <ol><li>複合材料の調製 注: 注意、ご使用する前に関連するすべての材料安全データ用紙 (MSDS) を参照してください。いくつかのこれらのメソッドで使用される化学物質の有毒で発がん性があります。ナノ材料の一括対応と比較して追加の危険があります。工学的制御 (ヒューム フード、グローブ ボックス) と個人用保護具 (保護メガネ、手袋、白衣、フルレングス パンツ、閉じてつま先の靴) の使用を含む、実験を実行するときにすべての適切な安全対策を使用してください 。
	注: アプリケーションによっては、補強繊維の種類することができます 1 つまたは以下の組み合わせ: 一方向繊維、織物、不織布・ フェルト、切り刻まれた繊維。
	<ol><li>方向繊維型 <ol><li>を使用する最も便利な中古含浸複合材料 (プリプレグ) を使用します</li>。
			<li>は、0 ° と 90 ° の分割を避けるためを含む積層順序のプリプレグをスタックします。たとえば、スタックに [0 3 90/3] s.</li>
		</ol></li> <li>織布タイプ <ol><li>準備平織炭素繊維およびフィルム型エポキシ樹脂です。プリプレグを使用している場合手順 1.1.2.1 に 1.1.2.6</li>。
			<li>は、99.5% アセトンまたは脱脂のため他の溶剤で布を洗浄します。汚染を避けるために洗浄後、布を処理するときは注意が必要。きれいな表面または糸くずのワイプに布を配置します</li>。
			<li>10 分の周囲条件下で乾燥することによって溶媒を除去</li>
			<li>皮バックアップ エポキシ樹脂膜を切り、カーボン生地の 1 プライにフィルム型エポキシの 1 プライを添付します</li>。
			<li>は事前に 10 70 ° C まで加熱されたホット プレート上エポキシ添付カーボン生地を配置前含浸用 s.</li>
			<li>10 min. の周囲条件で準備されたプリプレグを冷却し、その他のバックアップのフィルムの剥がし</li>。
			<li>希望の積層で布をスタック; たとえば、[0] にスタック 3.</li>
		</ol></li> <li>不織感じた <ol><li>非編まれたフェルトを準備します</li>。
			<li>は、99.5% アセトンまたは他の溶剤脱脂のフェルトを浄化します。汚染を避けるためにクレンジング後フェルトを処理するときは注意が必要。きれいな表面または糸くずのワイプにフェルトを配置します</li>。
			<li>皮バックアップ エポキシ樹脂膜を切り、フィルム型エポキシ樹脂の 3 プライを両側に感じたカーボンの 1 プライにアタッチします</li>。
			<li>場所エポキシ添付炭素は 10 の 70 ° C に予熱、ホット プレートに感じた前含浸用 s.</li>
			<li>10 min. の周囲条件で準備されたプリプレグを冷却し、その他のバックアップのフィルムの剥がし</li>。
		</ol></li></ol></li> <li>ソフト層の準備 注: 柔らかな層、ポリテトラフルオロ エチレン (PTFE)、フッ化エチレン プロピレン (FEP)、あるいはポリエチレン、ポリプロピレンなどのポリオレフィンなどフッ素樹脂またはシリコーンゴム、フッ素ゴムなどの合成ゴムを使用することができます。このプロトコルでは FEP フィルムを採用し、その降伏強度滴以上大幅に 120 ° c. 25 μ m 厚 FEP は一方向繊維や不織フェルト複合材料に適した厚み 100 μ m 厚の FEP は編まれた生地のために適切複合 10 を入力します。
	<ol><li>浄化 99.5% アセトンで柔らかな層。シワやピンホールを避けるために注意して処理します</li>。
		<li>ワイプ ソフト アセトン オフ層糸くずのおしりふき。それは硬化プロセス中にコンポジットに転送されますは柔らかな層に汚染がないことを確認します。これらは合成だけでなく、圧縮金型を傷つける恐れがありますので、ほこりや小さな粒子から柔らかな層が常します</li>。
	</ol></li></ol> 2。複合加工 <ol><li>圧縮金型の取り付け <ol><li>サイズ 120 mm × 120 mm の空洞を持つ圧縮金型を準備します</li>。
		<li>は、圧縮金型に離型を適用します。単にペースト スプレー、金型の離型や金型リリースままの薄い層のみまで糸くずのおしりふきで拭いてください</li>。
		<li>準備された複合材料積層板の 118 × 118 mm のサイズにカットします</li>。
		<li>下型 FEP フィルム 25 μ m 厚の場所 1 プライします</li>。
		<li>FEP フィルム複合材料積層板を配置し、積層物の別の FEP フィルムを配置します</li>。
		<li>柔らかな層を平らにし、ソフト層と積層間捕捉された空気の泡を削除します</li>。
		<li>圧縮成形用金型を閉じます</li>。
	</ol></li> <li>圧縮成形 <ol><li>熱ホットプレス 150 ° C 
		注: 金型試験片の温度は、この状態で 140 ° C です。低温の使用もエラストマーまたはポリオレフィン系樹脂が柔らかな層を採用している場合に可能です。複合材料の硬化温度と硬化温度を決定する柔らかな層の軟化温度の両方を考慮します</li>。
		<li>ホット プレスの金型を配置します</li>。
		ホット プレスを使用して <li>適用圧力; 硬化スケジュールと圧力は、複合型に依存します。
		<ol><li>方向繊維複合材料の適用 30 分 20 MPa の定圧; 追加のプロセスは必要ありません</li>。
			<li>不織布タイプ複合の 20 MPa を適用します。4 分、8 分後でゼロに圧力を解放し、すぐに 20 MPa を再度適用します 。
			注: このプロセスは、パージと呼ばれます、その目的は、削除過剰な樹脂と内包された空気の泡。複合材料; のサイズによってパージ ステップ数を増加可能性があります。大きいサイズの複合材料は、詳細パージを必要とします。
			<ol><li>ただし、樹脂の粘度を高めるために、開始後パージしません。合計で 30 分間治療します</li>。
			</ol></li> <li>非編まれたフェルト型コンポジット、適用圧力オーバー シュートは、ボイドが発生の 30 分注意 3 MPa と最終製品の欠陥。圧力オーバー シュートを避けるためにゆっくりと圧力を高める</li>。
		</ol></li> <li>ホット プレスで圧縮金型を作製した複合材料のガラス転移温度は、120 の ° C 以下に圧力を解放せずクールします</li>。
		<li>圧力を解放し、ホットプレスから圧縮金型を削除します</li>。
		<li>圧縮金型から最終製品を脱型します</li>。
	</ol>
	</li>
</ol>

<ol>
	<li>Hwang, I. U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bipolar+plate+made+of+carbon+fiber+epoxy+composite+for+polymer+electrolyte+membrane+fuel+cells.">Bipolar plate made of carbon fiber epoxy composite for polymer electrolyte membrane fuel cells.</a> J Power Sources. 184 (1), 90-94 (2008).</li><li>Avasarala, B., Haldar, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+surface+roughness+of+composite+bipolar+plates+on+the+contact+resistance+of+a+proton+exchange+membrane+fuel+cell.">Effect of surface roughness of composite bipolar plates on the contact resistance of a proton exchange membrane fuel cell.</a> J Power Sources. 188 (1), 225-229 (2009).</li><li>Yu, H. N., Lim, J. W., Kim, M. K., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma+treatment+of+the+carbon+fiber+bipolar+plate+for+PEM+fuel+cell.">Plasma treatment of the carbon fiber bipolar plate for PEM fuel cell.</a> Compos Struct. 94 (5), 1911-1918 (2012).</li><li>Lim, J. W., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+composite-metal+hybrid+bipolar+plates+for+PEM+fuel+cells.">Development of composite-metal hybrid bipolar plates for PEM fuel cells.</a> Int J Hydrogen Energy. 37 (17), (2012).</li><li>Kim, B. G., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electromagnetic-carbon+surface+treatment+of+composite+bipolar+plate+for+high-efficiency+polymer+electrolyte+membrane+fuel+cells.">Electromagnetic-carbon surface treatment of composite bipolar plate for high-efficiency polymer electrolyte membrane fuel cells.</a> J Power Sources. 195 (6), 1577-1582 (2010).</li><li>Kim, B. G., Lim, J. W., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+single-type+aluminum/composite+hybrid+bipolar+plate+with+surface+modification+for+high+efficiency+PEMFC.">A single-type aluminum/composite hybrid bipolar plate with surface modification for high efficiency PEMFC.</a> Int J Hydrogen Energy. 36 (4), 3087-3095 (2011).</li><li>Yu, H. N., Lim, J. W., Suh, J. D., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+graphite-coated+carbon+fiber+epoxy+composite+bipolar+plate+for+polymer+electrolyte+membrane+fuel+cell.">A graphite-coated carbon fiber epoxy composite bipolar plate for polymer electrolyte membrane fuel cell.</a> J Power Sources. 196 (23), 9868-9875 (2011).</li><li>Kim, K. H., Kim, B. G., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+carbon+composite+bipolar+plate+(BP)+for+vanadium+redox+flow+battery+(VRFB).">Development of carbon composite bipolar plate (BP) for vanadium redox flow battery (VRFB).</a> Compos Struct. 109, 253-259 (2014).</li><li>Lee, D., Lim, J. W., Nam, S., Choi, I., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gasket-integrated+carbon/silicone+elastomer+composite+bipolar+plate+for+high-temperature+PEMFC.">Gasket-integrated carbon/silicone elastomer composite bipolar plate for high-temperature PEMFC.</a> Compos Struct. 128, 284-290 (2015).</li><li>Lee, D., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electro-mechanical+properties+of+the+carbon+fabric+composites+with+fibers+exposed+on+the+surface.">Electro-mechanical properties of the carbon fabric composites with fibers exposed on the surface.</a> Compos Struct. 140, 77-83 (2016).</li><li>Lee, D., Lim, J. W., Nam, S., Choi, I., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+for+exposing+carbon+fibers+on+composite+bipolar+plates.">Method for exposing carbon fibers on composite bipolar plates.</a> Compos Struct. 134, 1-9 (2015).</li><li>Lee, D., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+composite+bipolar+plate+for+high-temperature+proton+exchange+membrane+fuel+cells+(HT-PEMFCs).">Carbon composite bipolar plate for high-temperature proton exchange membrane fuel cells (HT-PEMFCs).</a> J Power Sources. 327, 119-126 (2016).</li><li>Lee, D., Choe, J., Nam, S., Lim, J. W., Choi, I., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+non-woven+carbon+felt+composite+bipolar+plates+using+the+soft+layer+method.">Development of non-woven carbon felt composite bipolar plates using the soft layer method.</a> Compos struct. 160, 976-982 (2016).</li><li>Lee, D., Lim, J. W., Lee, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cathode/anode+integrated+composite+bipolar+plate+for+high-temperature+PEMFC.">Cathode/anode integrated composite bipolar plate for high-temperature PEMFC.</a> Compos Struct. 167, 144-151 (2017).</li><li>Lee, D., Oh, Y., Nam, S., Choe, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adhesion+Characteristics+of+Fiber-exposed+Glass+Composites.">Adhesion Characteristics of Fiber-exposed Glass Composites.</a> Compos Struct. 165, 9-14 (2017).</li></ol>

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ソフト層法は、製造コストと従来の方法と比較して重要な利点を提供します。3 種類ソフト層法による複合材料のすべては、電気的特性、機械的特性、ガス透過性と接着特性の面でユニークな特性を示します。
電気的特性の測定、4 点プローブ法が使用されました。ASR を 5 回測定し、そのバイポーラ プレートの代表値として平均値をとった。5 つのバイポーラ プレート?...

バイポーラ プレートは、エネルギー変換システム、燃料電池や電池などのエネルギー貯蔵システムの多機能キー コンポーネントです。バイポーラ プレートの主要な機能の要件は次のとおりです: 高圧縮圧力と外部の影響と高に耐えられるようにオーム損失、高い機械的性質を減らすために板厚方向の高い電気伝導度大量生産の生産性。
黒鉛とバイポーラ プレート用材料として採用された従来の金属と比較して、炭素繊維/エポキシ複合材料ある高い強度と剛性、システムの重量が大幅に削減できることを示す従来のバイポーラ プレート材料を複合材1に置き換えます。ただし、従来炭素繊維/エポキシ複合材料複合表面上に形成された樹脂リッチな層による大面積比抵抗 (ASR) の結果、板厚方向に電気伝導度貧しいがあります。絶縁樹脂リッチな層は導電性炭素繊維と別のバイポーラ プレート、ガス拡散層、(GDL) など、隣接するコンポーネント間の直接の接触を防ぎ、炭素電極 (CFE) を感じた。
樹脂リッチな層による高い ASR を解決する多くの研究を行った。最初のアプローチは、樹脂リッチな層を選択的に削除する表面処理方法をだった。たとえば、機械的な研磨は表面2に樹脂を削除しようとしています。ただし、炭素繊維も被害を受けた、貧しい ASR につながった。プラズマ治療3,4とマイクロ波治療方法5,6も、ファイバーの破損を避けるために開発されたが、それらは均一化と低生産性で起因しました。2 番目の方法では、導電性層塗装方法には、膨張黒鉛コーティング7,8が含まれています。このメソッドは、正常に ASR を削減、複合バイポーラ プレートを製造するための標準的な方法と見なされています。しかし、それは高価、機械的強度が低いため耐久性・剥離の問題があります。
本研究では複合バイポーラ プレート表面に炭素繊維を公開できる製法小説「軟層法」が示されていますいます。このメソッドの主な目的は、低製造コストの低い ASR を取得することです。ソフト層法は、圧縮型とバイポーラ プレート間高分子リリース フィルムなどの薄いソフト層を採用しています。圧縮型と柔らかな層のデタッチに硬化後バイポーラ製缶は炭素繊維が、後表面処理表面に露出を表示します。このメソッドだけでなく ASR を減少も大幅機械的性質の向上、ガス透過性の問題を解決しました。このメソッドは、他の多くの目的のため適用できる: 導電性プレートの薄い複合材の製造と表面処理なし共同接着剤の試作開発。

<table><tbody><tr><td>Unidirectional carbon/epoxy prepreg</td><td>SK Chemicals</td><td>USN020</td><td>Used to fabricate unidirectional carbon composite</td></tr><tr><td>Plain weave carbon fabric/epoxy prepreg</td><td>SK Chemicals</td><td>WSN 1k</td><td>Used to fabricate fabric carbon composite</td></tr><tr><td>Plain weave carbon fabric</td><td>SK Chemicals</td><td>C-112</td><td>Used to fabricate fabric carbon composite</td></tr><tr><td>Non-woven carbon felt</td><td>Newell</td><td>Graphite felt 3 mm</td><td>Used to fabricated felt carbon composite</td></tr><tr><td>Film type epoxy resin</td><td>SK Chemicals</td><td>K51</td><td>Used as a matrix of the composite</td></tr><tr><td>Acetone 99.5%</td><td>Samchun</td><td>67-64-1</td><td>Used to cleanse the carbon fiber and the soft layers</td></tr><tr><td>Mold release</td><td>ShinEtsu</td><td>KF-96</td><td>Used to coat the mold</td></tr><tr><td>Release film</td><td>Airtech</td><td>A4000V</td><td>Used as a soft layer</td></tr><tr><td>Compression mold</td><td>N/A</td><td>N/A</td><td>Machined in lab. Material: NAK80</td></tr><tr><td>Hot press</td><td>Hydrotek 100</td><td>N/A</td><td>Used to apply pressure and heat</td></tr><tr><td>Scanning electron microscope</td><td>FEI Compnay</td><td>Magellan 400</td><td>Used to investigate the surface of the composite</td></tr></tbody></table>

experimental implementation of a new composite fabrication method: exposing bare fibers on the composite surface by the soft layer method

バイポーラ プレートは、プロトン交換膜燃料電池 (固体) とバナジウム レドックス フロー電池 (VRFBs) の重要なコンポーネントです。高い電気伝導度、高い機械的性質、高い生産性多機能コンポーネントです。
この点で、炭素繊維/エポキシ樹脂複合材料は多くの固有のもろさのためシステム全体の壊滅的な障害につながる従来の黒鉛セパレーターを交換する理想的な材料をすることができます。炭素繊維/エポキシ複合材料は、高い機械的性質を持って、製造が容易な板厚方向の電気伝導度は樹脂リッチな層がその表面に形成するため貧しいです。したがって、膨張黒鉛コーティングは、導電性の問題を解決するために採択されました。しかし、膨張黒鉛コーティングだけでなく製造コストの増加、貧困層の力学的性質があります。
本研究では複合表面の繊維を公開するメソッドが示されています。複合材料の加工後の表面処理による繊維を公開することができます現在多くの方法があります。ただし、この新しい方法は表面処理を不要繊維、複合材料の製造時に公開されているためです。表面にカーボン ファイバーを公開すると、電気伝導度と複合材料の機械的強度を大幅に増加します。

作製した標本は、走査型電子顕微鏡 (SEM) (図 1) を使用して観察されます。繊維の上をカバーする樹脂リッチな層がわずか数ミクロンの厚さには、供試体の上部に観察光学顕微鏡像は適していません。5 ° で試料を傾斜による SEM 画像は代表的な画像を提供します。樹脂で覆われた表面には、従来の圧縮成形により作製した複合材料と比較して、複...

Watch this Scientific Journal Video about Experimental Implementation of a New Composite Fabrication Method: Exposing Bare Fibers on the Composite Surface by the Soft Layer Method at JoVE.com

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

ガレージの豊富な領域を排除することによって複合表面にファイバーを公開するためのプロトコルが表示されます。繊維がポストの表面処理ではなく、複合体の製造中にさらされています。公開される炭素複合材料は、板厚方向と高い機械的性質で高い電気伝導度を表わします。

新しい複合加工法の試作: 軟層法による複合表面にファイバーを公開

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 ...

experimental-implementation-new-composite-fabrication-method-exposing

Universidad San Sebastian

Research

JoVE Journal

Engineering

8.2K ビュー.  Korea Advanced Institute of Science and Technology. ガレージの豊富な領域を排除することによって複合表面にファイバーを公開するためのプロトコルが表示されます。繊維がポストの表面処理ではなく、複合体の製造中にさらされています。公開される炭素複合材料は、板厚方向と高い機械的性質で高い電気伝導度を表わします。

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

Fabricating Metamaterials Using the Fiber Drawing Method

Metamaterials are man-made composite materials, fabricated by assembling components much smaller than the wavelength at which they operate 1. They owe their electromagnetic properties to the structure of their constituents, instead of the atoms that compose them. For example, sub-wavelength metal wires can be arranged to possess an effective electric permittivity that is either positive or negative at a given frequency, in contrast to the metals themselves 2. This unprecedented control over the behaviour of light can potentially lead to a number of novel devices, such as invisibility cloaks 3, negative refractive index materials 4, and lenses that resolve objects below the diffraction limit 5. However, metamaterials operating at optical, mid-infrared and terahertz frequencies are conventionally made using nano- and micro-fabrication techniques that are expensive and produce samples that are at most a few centimetres in size 6-7. Here we present a fabrication method to produce hundreds of meters of metal wire metamaterials in fiber form, which exhibit a terahertz plasmonic response 8. We combine the stack-and-draw technique used to produce microstructured polymer optical fiber 9 with the Taylor-wire process 10, using indium wires inside polymethylmethacrylate (PMMA) tubes. PMMA is chosen because it is an easy to handle, drawable dielectric with suitable optical properties in the terahertz region; indium because it has a melting temperature of 156.6 &deg;C which is appropriate for codrawing with PMMA. We include an indium wire of 1 mm diameter and 99.99% purity in a PMMA tube with 1 mm inner diameter (ID) and 12 mm outside diameter (OD) which is sealed at one end. The tube is evacuated and drawn down to an outer diameter of 1.2 mm. The resulting fiber is then cut into smaller pieces, and stacked into a larger PMMA tube. This stack is sealed at one end and fed into a furnace while being rapidly drawn, reducing the diameter of the structure by a factor of 10, and increasing the length by a factor of 100. Such fibers possess features on the micro- and nano- scale, are inherently flexible, mass-producible, and can be woven to exhibit electromagnetic properties that are not found in nature. They represent a promising platform for a number of novel devices from terahertz to optical frequencies, such as invisible fibers, woven negative refractive index cloths, and super-resolving lenses.

Metamaterials at terahertz frequencies offer unique opportunities, but are challenging to fabricate in bulk. We adapt the fabrication procedure for microstructured polymer optical fibers to inexpensively fabricate metamaterials potentially on an industrial scale. We produce polymethylmethacrylate fibers containing ~10 &mu;m diameter indium wires separated by ~100 &mu;m, which exhibit a terahertz plasmonic response.

ファイバー描画法を用いたメタマテリアルの作製

Metamaterials are man-made composite materials, fabricated by assembling components much smaller than the wavelength at which they operate 1. They owe ...

工学

Process of Making Three-dimensional Microstructures using Vaporization of a Sacrificial Component

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material fabrication techniques are able to mimic the complexity of these structures while maintaining scalability. The Vaporization of a Sacrificial Component (VaSC) process is able to do so. This process uses sacrificial fibers as a template to form hollow, cylindrical microchannels embedded within a matrix. Tin (II) oxalate (SnOx) is embedded within poly(lactic) acid (PLA) fibers which facilitates the use of this process. The SnOx catalyzes the depolymerization of the PLA fibers at lower temperatures. The lactic acid monomers are gaseous at these temperatures and can be removed from the embedded matrix at temperatures that do not damage the matrix. Here we show a method for aligning these fibers using micromachined plates and a tensioning device to create complex patterns of three-dimensionally arrayed microchannels. The process allows the exploration of virtually any arrangement of fiber topologies and structures.

The Vaporization of a Sacrificial Component (VaSC) process is used to fabricate microvascular structures. This procedure uses sacrificial poly(lactic) acid fibers to form hollow microchannels with precise 3D geometric positioning provided by laser micromachined guide plates.

犠牲成分の蒸発を用いた三次元微細構造を作る過程

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material ...

Strain Sensing Based on Multiscale Composite Materials Reinforced with Graphene Nanoplatelets

The electrical response of NH2-functionalized graphene nanoplatelets composite materials under strain was studied. Two different manufacturing methods are proposed to create the electrical network in this work: (a) the incorporation of the nanoplatelets into the epoxy matrix and (b) the coating of the glass fabric with a sizing filled with the same nanoplatelets. Both types of multiscale composite materials, with an in-plane electrical conductivity of ~10-3 S/m, showed an exponential growth of the electrical resistance as the strain increases due to distancing between adjacent functionalized graphene nanoplatelets and contact loss between overlying ones. The sensitivity of the materials analyzed during this research, using the described procedures, has been shown to be higher than commercially available strain gauges. The proposed procedures for self-sensing of the structural composite material would facilitate the structural health monitoring of components in difficult to access emplacements such as offshore wind power farms. Although the sensitivity of the multiscale composite materials was considerably higher than the sensitivity of metallic foils used as strain gauges, the value reached with NH2 functionalized graphene nanoplatelets coated fabrics was nearly an order of magnitude superior. This result elucidated their potential to be used as smart fabrics to monitor human movements such as bending of fingers or knees. By using the proposed method, the smart fabric could immediately detect the bending and recover instantly. This fact permits precise monitoring of the time of bending as well as the degree of bending.

The integration of conductive nanoparticles, such as graphene nanoplatelets, into glass fiber composite materials creates an intrinsic electrical network susceptible to strain. Here, different methods to obtain strain sensors based on the addition of graphene nanoplatelets into the epoxy matrix or as a coating on glass fabrics are proposed.

グラフェンナノプレートレットとマルチスケール複合材料強化に基づくひずみセンシング

The electrical response of NH2-functionalized graphene nanoplatelets composite materials under strain was studied. Two different manufacturing methods are ...

Microfluidic Fabrication of Polymeric and Biohybrid Fibers with Predesigned Size and Shape

A &#8220;sheath&#8221; fluid passing through a microfluidic channel at low Reynolds number can be directed around another &#8220;core&#8221; stream and used to dictate the shape as well as the diameter of a core stream.&#160;Grooves in the top and bottom of a microfluidic channel were designed to direct the sheath fluid and shape the core fluid.&#160;By matching the viscosity and hydrophilicity of the sheath and core fluids, the interfacial effects are minimized and complex fluid shapes can be formed.&#160;Controlling the relative flow rates of the sheath and core fluids determines the cross-sectional area of the core fluid.&#160;Fibers have been produced with sizes ranging from 300 nm to ~1 mm, and fiber cross-sections can be round, flat, square, or complex as in the case with double anchor fibers. Polymerization of the core fluid downstream from the shaping region solidifies the fibers.&#160;Photoinitiated click chemistries are well suited for rapid polymerization of the core fluid by irradiation with ultraviolet light.&#160;Fibers with a wide variety of shapes have been produced from a list of polymers including liquid crystals, poly(methylmethacrylate), thiol-ene and thiol-yne resins, polyethylene glycol, and hydrogel derivatives. Minimal shear during the shaping process and mild polymerization conditions also makes the fabrication process well suited for encapsulation of cells and other biological components.

Two adjacent fluids passing through a grooved microfluidic channel can be directed to form a sheath around a prepolymer core; thereby&#160;determining both shape and cross-section. Photoinitiated polymerization, such as thiol click chemistry, is well suited for rapidly solidifying the core fluid into a microfiber with predetermined size and shape.

あらかじめ設計されたサイズと形状を用いるポリマー繊維およびバイオハイブリッド繊維のマイクロ流体製造

A &#8220;sheath&#8221; fluid passing through a microfluidic channel at low Reynolds number can be directed around another &#8220;core&#8221; stream and ...

生物工学

Microfluidic-based Synthesis of Covalent Organic Frameworks (COFs): A Tool for Continuous Production of COF Fibers and Direct Printing on a Surface

Covalent Organic Frameworks (COFs) are a class of porous covalent materials which are frequently synthesized as unprocessable crystalline powders. The first COF was reported in 2005 with much effort centered on the establishment of new synthetic routes for its preparation. To date, most available synthetic methods for COF synthesis are based on bulk mixing under solvothermal conditions. Therefore, there is increasing interest in developing systematic protocols for COF synthesis that provide for fine control over reaction conditions and improve COF processability on surfaces, which is essential for their use in practical applications. Herein, we present a novel microfluidic-based method for COF synthesis where the reaction between two constituent building blocks, 1,3,5-benzenetricarbaldehyde (BTCA) and 1,3,5-tris(4-aminophenyl)benzene (TAPB), takes place under controlled diffusion conditions and at room temperature. Using such an approach yields sponge-like, crystalline fibers of a COF material, hereafter called MF-COF. The mechanical properties of MF-COF and the dynamic nature of the approach allow the continuous production of MF-COF fibers and their direct printing onto surfaces. The general method opens new potential applications requiring advanced printing of 2D or 3D COF structures on flexible or rigid surfaces.

Microfluidic-based Synthesis of Covalent Organic Frameworks COFs: A Tool for Continuous Production of COF Fibers and Direct Printing on a Surface

We present a novel microfluidic-based method for synthesis of covalent organic frameworks (COFs). We demonstrate how this approach can be used to produce continuous COF fibers, and also 2D or 3D COF structures on surfaces.

コバレント有機骨格（COF）のマイクロ流体ベースの合成：COF繊維の連続生産と表面への直接印刷のためのツール

Covalent Organic Frameworks (COFs) are a class of porous covalent materials which are frequently synthesized as unprocessable crystalline powders. The ...

化学

Microfluidic Dry-spinning and Characterization of Regenerated Silk Fibroin Fibers

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables the silk proteins to be compact and ordered by shearing and elongation forces. Here, a biomimetic microfluidic channel was designed to mimic the specific geometry of the spinning duct of the silkworm. Regenerated silk fibroin (RSF) spinning doped with high concentration, was extruded through the microchannel to dry-spin fibers at ambient temperature and pressure. In the post-treated process, the as-spun fibers were drawn and stored in ethanol aqueous solution. Synchrotron radiation wide-angle X-ray diffraction (SR-WAXD) technology was used to investigate the microstructure of single RSF fibers, which were fixed to a sample holder with the RSF fiber axis normal to the microbeam of the X-ray. The crystallinity, crystallite size, and crystalline orientation of the fiber were calculated from the WAXD data. The diffraction arcs near the equator of the two-dimensional WAXD pattern indicate that the post-treated RSF fiber has a high orientation degree.

A protocol for the microfluidic spinning and microstructure characterization of regenerated silk fibroin monofilament is presented.

マイクロ流体ドライ回転と再生絹フィブロイン繊維の特性

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables ...

Manufacturing Of Robust Natural Fiber Preforms Utilizing Bacterial Cellulose as Binder

A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose and short sisal fibers are dispersed into a water suspension containing bacterial cellulose. The fiber and nanocellulose suspension is then filtered (using vacuum or gravity) and the wet filter cake pressed to squeeze out any excess water, followed by a drying step. This will result in the hornification of the bacterial cellulose network, holding the loose natural fibers together.
Our method is specially suited for the manufacturing of rigid and robust preforms of hydrophilic fibers. The porous and hydrophilic nature of such fibers results in significant water uptake, drawing in the bacterial cellulose dispersed in the suspension. The bacterial cellulose will then be filtered against the surface of these fibers, forming a bacterial cellulose coating. When the loose fiber-bacterial cellulose suspension is filtered and dried, the adjacent bacterial cellulose forms a network and hornified to hold the otherwise loose fibers together.
The introduction of bacterial cellulose into the preform resulted in a significant increase of the mechanical properties of the fiber preforms. This can be attributed to the high stiffness and strength of the bacterial cellulose network. With this preform, renewable high performance hierarchical composites can also be manufactured by using conventional composite production methods, such as resin film infusion (RFI) or resin transfer molding (RTM). Here, we also describe the manufacturing of renewable hierarchical composites using double bag vacuum assisted resin infusion.

We present a novel method of manufacturing rigid and robust short natural fiber preforms using a papermaking process. Bacterial cellulose acts simultaneously as the binder for the loose fibers and provides rigidity to the fiber preforms. These preforms can be infused with a resin to produce truly green hierarchical composites.

バインダーとしてのバクテリアセルロースを利用堅牢な天然繊維プリフォームの製造

A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose ...

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.

磁石は、複合材生産を支援: 柔軟な新しい技術高圧真空袋/Lay アップ プロセスを達成するため

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

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.

柔軟な単方向複合ラミネートの切断手順、引張試験、およびエージング

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.

木材ベースの高性能複合材料の製造と設計

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

新しい複合加工法の試作: 軟層法による複合表面にファイバーを公開

要約

さらに動画を探す

この動画の章

ファイバー描画法を用いたメタマテリアルの作製

犠牲成分の蒸発を用いた三次元微細構造を作る過程

グラフェンナノプレートレットとマルチスケール複合材料強化に基づくひずみセンシング

あらかじめ設計されたサイズと形状を用いるポリマー繊維およびバイオハイブリッド繊維のマイクロ流体製造

コバレント有機骨格（COF）のマイクロ流体ベースの合成：COF繊維の連続生産と表面への直接印刷のためのツール

マイクロ流体ドライ回転と再生絹フィブロイン繊維の特性

バインダーとしてのバクテリアセルロースを利用堅牢な天然繊維プリフォームの製造

磁石は、複合材生産を支援: 柔軟な新しい技術高圧真空袋/Lay アッププロセスを達成するため

柔軟な単方向複合ラミネートの切断手順、引張試験、およびエージング

木材ベースの高性能複合材料の製造と設計

新しい複合加工法の試作: 軟層法による複合表面にファイバーを公開

要約

さらに動画を探す

この動画の章

ファイバー描画法を用いたメタマテリアルの作製

犠牲成分の蒸発を用いた三次元微細構造を作る過程

グラフェンナノプレートレットとマルチスケール複合材料強化に基づくひずみセンシング

あらかじめ設計されたサイズと形状を用いるポリマー繊維およびバイオハイブリッド繊維のマイクロ流体製造

コバレント有機骨格（COF）のマイクロ流体ベースの合成：COF繊維の連続生産と表面への直接印刷のためのツール

マイクロ流体ドライ回転と再生絹フィブロイン繊維の特性

バインダーとしてのバクテリアセルロースを利用堅牢な天然繊維プリフォームの製造

磁石は、複合材生産を支援: 柔軟な新しい技術高圧真空袋/Lay アップ プロセスを達成するため

柔軟な単方向複合ラミネートの切断手順、引張試験、およびエージング

木材ベースの高性能複合材料の製造と設計

磁石は、複合材生産を支援: 柔軟な新しい技術高圧真空袋/Lay アッププロセスを達成するため