高潔,陳樹存,唐浩奎,滕叢叢,赫珍珍,曹宏,李家勁,薛俊
武漢工程大學(xué)材料科學(xué)與工程學(xué)院,湖北 武漢 430074
碳包覆納米粒子系導(dǎo)電涂料的制備與性能
高潔,陳樹存,唐浩奎,滕叢叢,赫珍珍,曹宏,李家勁,薛俊*
武漢工程大學(xué)材料科學(xué)與工程學(xué)院,湖北 武漢 430074
以自制碳包覆銅鎳合金納米粒子為填料,醇酸樹脂為成膜劑,共混制備了碳包覆銅鎳合金納米粒子/醇酸樹脂導(dǎo)電復(fù)合涂料.X射線衍射分析和透射電子顯微鏡觀察表明,碳包覆銅鎳合金納米粒子為核殼結(jié)構(gòu),核為銅-鎳合金,殼為石墨化碳.分別添加占涂料總質(zhì)量的3%、5%、10%、15%及20%(質(zhì)量分?jǐn)?shù))的填料制備涂料,探討了碳包覆銅鎳合金納米粒子添加量對(duì)涂料性能的影響.并對(duì)所制備涂料的黏度、導(dǎo)電性,漆膜附著力、吸波性進(jìn)行了表征測試.結(jié)果表明,隨著碳包覆銅鎳合金納米粒子添加量增加,涂料黏度單調(diào)增大,電阻單調(diào)減小,最大粘度為180 mm2/s,最小電阻為2×107Ω.當(dāng)碳包覆銅鎳合金納米粒子質(zhì)量分?jǐn)?shù)為15%時(shí)漆膜附著力最佳,脫落面積綜合評(píng)定等級(jí)為0;當(dāng)質(zhì)量分?jǐn)?shù)為20%時(shí),漆膜有較好吸波性能,反射損耗峰值為-2.7 dB,吸收帶寬為2 GHz(14~16 GHz).
共混;納米粒子;醇酸樹脂;電性能;吸波性能
隨著納米技術(shù)的飛速發(fā)展,新型納米材料在涂料領(lǐng)域得到了大量應(yīng)用,納米技術(shù)不僅優(yōu)化了傳統(tǒng)涂料的各項(xiàng)性能,而且為功能涂料這一研究熱點(diǎn)提供了廣闊的思路和全新的視角.1993年Rouff[1]和Tomita[2]等人首次發(fā)現(xiàn)了碳包覆LaC2納米粒子.這種具有核殼結(jié)構(gòu)的金屬/碳復(fù)合納米粒子又被稱為碳包覆金屬納米粒子(Carbon-encapsulated metal nanoparticles,CEMNPs)[3-5],是一種碳?xì)ぐ硪环N物質(zhì)的納米復(fù)合材料,其碳層性質(zhì)相對(duì)穩(wěn)定,可以防止金屬納米粒子長大和團(tuán)聚,可以保護(hù)金屬粒子不與其他介質(zhì)發(fā)生氧化、還原、化合、分解等反應(yīng)[6-7].醇酸樹脂以產(chǎn)量大價(jià)格低廉的優(yōu)勢廣泛應(yīng)用于涂料領(lǐng)域,且成膜后光澤柔韌,具有很好的附著力,耐磨性以及耐候性,將碳包覆金屬納米粒子與醇酸樹脂復(fù)合有望提高涂料的基礎(chǔ)性能以及增加涂料的導(dǎo)電功能.本實(shí)驗(yàn)以碳包覆銅鎳合金納米粒子(簡稱CuNi@C)為填料,通過共混的方法與醇酸樹脂復(fù)配制備成了復(fù)合涂料,重點(diǎn)對(duì)涂料的基本性能、電性能及吸波性能[8-10]進(jìn)行了研究.
1.1 主要原料
碳包覆銅鎳合金納米粒子(CuNi@C),自制[11];醇酸樹脂(工業(yè)級(jí)),市售;無水乙醇(AR級(jí)),河南中促實(shí)業(yè)有限公司;硅烷偶聯(lián)劑(AR級(jí)),武漢博大科技有限公司;十二烷基苯磺酸鈉(AR級(jí)),國藥集團(tuán)化學(xué)試劑有限公司;聚酰胺(工業(yè)級(jí)),市售;稀釋劑(工業(yè)級(jí)),市售.
1.2 涂料制備過程
涂料配方設(shè)計(jì)如表1所示,其制備工藝如下:首先用硅烷偶聯(lián)劑和十二烷基苯磺酸鈉分散劑處理CuNi@C納米粒子的表面,然后將改性過的納米粒子粉末、醇酸樹脂、聚酰胺以及氧化鋁陶瓷球按照一定的比例和順序投入球磨罐中,高速(580 r/min)球磨2 h,最終將涂料與陶瓷球分離,將涂料密封保存,以備下一步噴涂[12].
涂料制備及噴涂流程如圖1.
1.3 結(jié)構(gòu)表征與性能測試
用涂-4黏度計(jì)測定涂料的黏度[13];用畫格法測定漆膜的附著力[14];用循環(huán)伏安法測定填料粉體以及涂料的導(dǎo)電性.材料吸波效能測試系統(tǒng)的建立參照了文獻(xiàn)[15]:它的工作頻率范圍是8~18 GHz.被測樣品的尺寸要求是300 mm×300 mm的正方形平板材料,測試單位為航天科工武漢磁電有限責(zé)任公司.
表1 涂料配方及黏度Table 1 Formula and viscocity of coating
圖1 工藝流程示意圖Fig.1 Schematic diagram of technological process
按照金屬源和碳源摩爾比為1∶1的比例稱取Cu(NO3)2·3H2O、Ni(NO3)2·6H2O和蔗糖,成功制備出了CuNi@C納米粒子,通過對(duì)其XRD分析(圖2),表明樣品中的碳有一定程度的石墨化.為了更準(zhǔn)確地觀察樣品的微觀結(jié)構(gòu),進(jìn)行了TEM測試,從圖3、圖4觀測分析,與XRD表征結(jié)果一致,證明樣品即是銅鎳合金納米粒子為核,碳層為殼的核/殼結(jié)構(gòu).
2.1 黏度
通過對(duì)涂-4黏度計(jì)測定數(shù)值的分析可知(表1),CuNi@C納米粒子的添加量對(duì)涂料黏度產(chǎn)生了明顯影響.當(dāng)CuNi@C納米粒子添加量不斷增加,涂料黏度也不斷攀升.當(dāng)CuNi@C納米粒子添加質(zhì)量分?jǐn)?shù)為最大20%時(shí),涂料黏度達(dá)到最大,為180mm2/s,說明改性后的CuNi@C納米粒子與醇酸樹脂充分結(jié)合,同時(shí)也在一定程度上提高了涂料的固含量.
2.2 附著力
圖2 CuNi@C的XRD圖Fig.2 XRD pattern of CuNi@C
圖3 CuNi@C的TEM圖Fig.3 TEM image of CuNi@C
圖4 CuNi@C的HRTEM圖Fig.4 HRTEM image of CuNi@C
不同CuNi@C納米粒子添加量的漆膜附著力?測試結(jié)果如表2,隨著CuNi@C含量的增加,附著力漸漸提高,當(dāng)CuNi@C質(zhì)量分?jǐn)?shù)為15%時(shí)漆膜附著力最好,說明填料對(duì)漆膜附著力有一定的影響;隨著CuNi@C含量繼續(xù)提高至20%時(shí),附著力有所降低,說明當(dāng)漆膜CuNi@C含質(zhì)量分?jǐn)?shù)超過15%時(shí),填料比例過高,導(dǎo)致醇酸樹脂的交聯(lián)密度降低,對(duì)漆膜附著力產(chǎn)生負(fù)面影響,所以當(dāng)CuNi@C添加質(zhì)量分?jǐn)?shù)為15%時(shí),漆膜附著力最佳,脫落面積綜合評(píng)定等級(jí)為0.
表2 漆膜附著力Table 2 Adhesion of coating
2.3 導(dǎo)電性能
實(shí)驗(yàn)測得CuNi@C系涂料的電流、電壓,可計(jì)算出涂料的體電阻,所測涂料的體積相同,那么所測得的涂料的體電阻可以反映涂料的導(dǎo)電性.隨著CuNi@C納米粒子添加量的增大,體電阻呈現(xiàn)急劇下降的趨勢;當(dāng)添加質(zhì)量分?jǐn)?shù)大于7%時(shí),涂料體電阻的下降趨勢漸緩且呈現(xiàn)線性變化,如圖5,說明隨著CuNi@C納米粒子含量的增加,粒子間距減小,導(dǎo)電依賴粒子間電子的傳遞,因此導(dǎo)電性越來越好,最小體電阻為2×107Ω.
2.4 吸波性能
圖6為空白板的反射率R和頻率f的關(guān)系曲線(上半部)以及質(zhì)量分?jǐn)?shù)為20%的CuNi@C涂料樣板的反射率R和頻率f的關(guān)系曲線(下半部),R值越小,表明電磁波的衰減量越大,材料的吸波性能越好.由圖6可以觀察到,在14~16 GHz這一頻率范圍內(nèi),R值達(dá)最小為-2.7 dB,計(jì)算可知最小反射率為53.7%,說明此時(shí)漆膜的吸波性能良好.而其他因素對(duì)漆膜吸波性的影響會(huì)在后續(xù)的實(shí)驗(yàn)中深入研究.
圖5 CuNi@C的含量與電阻的關(guān)系曲線Fig.5 Curve of relationship between the quantity of CuNi@C and resistance
圖6 空白板反射率R和頻率f的關(guān)系曲線(上半部)質(zhì)量分?jǐn)?shù)為20%CuNi@C涂料樣板的反射率R和頻率f的關(guān)系曲線(下半部)Fig.6 Curve of relationship between R and f of blank simple(upper half).Curve of relationship between R and f of 20%CuNi@C coating(lower half)
用共混的方法將CuNi@C納米粒子與醇酸樹脂復(fù)合,制備成復(fù)合涂料,實(shí)驗(yàn)表明兩者緊密復(fù)配,隨著添加量的質(zhì)量分?jǐn)?shù)由3%增至20%,體電阻逐漸下降,最小為2×107Ω,導(dǎo)電性能良好;當(dāng)添加質(zhì)量分?jǐn)?shù)為20%時(shí),涂料黏度達(dá)到最大180 mm2/s;當(dāng)添加質(zhì)量分?jǐn)?shù)為15%時(shí),漆膜附著力最佳,脫落面積綜合評(píng)定等級(jí)為0.因此綜上考慮,當(dāng)CuNi@C納米粒子質(zhì)量分?jǐn)?shù)為15%時(shí),涂料的綜合性能最佳;CuNi@C納米粒子質(zhì)量分?jǐn)?shù)為20%,在14~16 GHz這一頻率范圍內(nèi),漆膜的吸波性能良好,最小反射率為53.7%.
致謝
感謝湖北省自然科學(xué)基金項(xiàng)目、武漢工程大學(xué)研究生教育創(chuàng)新基金項(xiàng)目和武漢工程大學(xué)科學(xué)研究基金對(duì)本研究的資助!
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Preparation and properties of electrical conductive coating of carbon encapsulated nanoparticles
GAO Jie1,CHEN Shu-cun,TANG Hao-kui,TENG Cong-cong,HE Zhen-zhen,CAO Hong,LI Jia-jin,XUE Jun
School of Materials Science and Engineering,Wuhan Institute of Technology,Wuhan 430074,China
Conductive composite coatings were prepared by using the carbon encapsulated copper nickel alloy nanoparticles as fillers and the alkyd resins as film formers.Characterized by X-ray diffraction and transmission electron microscope,the nanoparticles of carbon encapsulated copper nickel alloy show core-shell structures with copper nickel alloy as the core and graphitized carbon as the shells.The coatings were prepared respectively with the filler mass fraction of 3%,5%,10%,15%and 20%.The effect of filler mass fraction on the performances of the coatings,including the electric and absorption properties,the viscosity and the adhesion was analyzed.The results suggest that the viscosity increases monotonously while the resistance decreases monotonously with the increase of the filler mass fraction,in which the maximum viscosity is 180 mm2/s and the minimum resistance is 2×107Ω.The adhesive force of the coating is best and reaches degree 0 when the filler addition is 15%.The coatings have excellent microwave absorbing properties with the reflection loss of-2.7 dB and the bandwidth of 2 GHz(14-16 GHz)at the filler mass fraction of 20%.
blend;nanoparticles;alkyd resin;electrical conductivity;microwave absorbing
TQ630.7
A
10.3969/j.issn.1674-2869.2015.11.007
1674-2869(2015)11-0033-05
本文編輯:龔曉寧
2015-09-08
湖北省自然科學(xué)基金項(xiàng)目(2014CFB788);武漢工程大學(xué)科學(xué)研究基金(K201465);武漢工程大學(xué)研究生教育創(chuàng)新基金項(xiàng)目(CX2014063)
高潔(1990-),女,河北石家莊人,碩士研究生.研究方向:功能材料.*通信聯(lián)系人.