超高分子量聚乙烯復(fù)合材料的制備與導(dǎo)熱性能研究
發(fā)布時間：2018-08-31 19:24
【摘要】：聚合物材料因質(zhì)量輕、價格低廉而應(yīng)用廣泛,然而熱絕緣性限制了其在微電子領(lǐng)域的應(yīng)用,如何提高聚合物材料導(dǎo)熱性能已成為該領(lǐng)域的研究熱點。提高聚合物導(dǎo)熱性能較普遍的方案就是通過粉末共混法將導(dǎo)熱粒子添加到聚合物基體中,導(dǎo)熱粒子包覆聚合物形成隔離結(jié)構(gòu),這種導(dǎo)熱網(wǎng)絡(luò)結(jié)構(gòu)方便聲子傳輸,使其快速散熱。但是,導(dǎo)熱粒子和聚合物基體之間的界面張力大,難以有效結(jié)合,兩相界面缺陷多,不利于提高聚合物熱導(dǎo)率。填料的幾何形態(tài)及其在基體中的分散狀態(tài)對界面結(jié)構(gòu)有顯著影響,另外混合型導(dǎo)熱粒子間存在協(xié)同效應(yīng),能夠在聚合物基體中形成具有隔離結(jié)構(gòu)的導(dǎo)熱通路,可有效減小界面熱阻。為此本文研究了不同形貌導(dǎo)熱粒子、混雜型導(dǎo)熱粒子、導(dǎo)熱復(fù)合材料制備工藝等對UHMWPE導(dǎo)熱性能、熱穩(wěn)定性影響。主要內(nèi)容及研究結(jié)果如下:通過粉末共混-熱壓法成功制備了具有隔離結(jié)構(gòu)的氮化硼/超高分子量聚乙烯(BN/UHMWPE)、氮化鋁/超高分子量聚乙烯(AlN/UHMWPE)、(氮化硼+碳納米管)/超高分子量聚乙烯((BN+MWCNT)/UHMWPE)三種復(fù)合材料。導(dǎo)熱性能研究顯示,復(fù)合材料熱導(dǎo)率隨著填料含量增加而增加,當(dāng)填料含量為50wt%時,熱導(dǎo)率(BN+MWCNT)/UHMWPEBN/UHMWPEAlN/UHMWPE,其中(BN+MWCNT)/UHMWPE 熱導(dǎo)率可達(dá)1.505Wm~(-1)K~(-1),較單一填料BN/UHMWPE 熱導(dǎo)率提高了 64%,表明 BN、MWCNT 二者間協(xié)同效應(yīng)有助于提高UHMWPE導(dǎo)熱性能。掃描電子電鏡(SEM)、光學(xué)顯微鏡(OM)、原子粒顯微鏡(AFM)研究表明BN片與MWCNT糾纏一起,較純BN、AlN復(fù)合材料內(nèi)部導(dǎo)熱網(wǎng)絡(luò)更為致密,說明不同類型導(dǎo)熱填料構(gòu)成的導(dǎo)熱網(wǎng)絡(luò)以及其邊界處界面不同,從而影響界面熱阻,進(jìn)而影響復(fù)合材料熱導(dǎo)率。熱失重(TGA)分析表明BN+MWCNT對復(fù)合材料的熱穩(wěn)定性影響并不明顯,這是由于導(dǎo)熱通路形成使基體內(nèi)部所產(chǎn)生的熱量可以快速散去。片狀BN與管狀MWCNT之間的協(xié)同作用能夠有效提高復(fù)合材料的熱導(dǎo)率。此外,對不同溫度、壓力模壓成型工藝所制備的BN/UHMWPE、(BN+MWCNT)/UHMWPE的微觀結(jié)構(gòu)、導(dǎo)熱性能進(jìn)行了研究。OM、SEM研究表明不同工藝影響著填料在基體中分散狀態(tài),其中冷壓-煅燒工藝所制備的復(fù)合材料內(nèi)部導(dǎo)熱網(wǎng)絡(luò)最為密集,但是這種網(wǎng)絡(luò)結(jié)構(gòu)在高溫高壓的處理條件下會被破壞,所以高溫高壓工藝所制備的復(fù)合材料的導(dǎo)熱性能發(fā)生下降。然而在(BN+MWCNT)/UHMWPE復(fù)合材料中,1D-MWCNT與2D-BN糾纏一起形成了 MWCNT-BN導(dǎo)熱網(wǎng)絡(luò),這種網(wǎng)絡(luò)結(jié)構(gòu)因其特殊結(jié)構(gòu)即使在高溫高壓工藝下也呈現(xiàn)了良好導(dǎo)熱性能,50wt%(BN+MWCNT)混雜填料填充UHMWPE熱導(dǎo)率可達(dá)1.761 Wm~(-1)K~(-1)。TGA分析表明填料在基體中分散狀態(tài)對復(fù)合材料熱穩(wěn)定性有一定影響。
[Abstract]:Polymer materials are widely used because of their light weight and low price. However, thermal insulation has limited their application in the field of microelectronics. How to improve the thermal conductivity of polymer materials has become a research hotspot in this field. The common way to improve the thermal conductivity of polymer is to add the thermal conductive particles to the polymer matrix by powder blending method, and the thermal conductivity particles cover the polymer to form an isolated structure. This heat conduction network structure is convenient for phonon transmission and makes it rapidly dissipate heat. However, the interfacial tension between the thermal conductive particles and the polymer matrix is large, it is difficult to combine effectively, and there are many defects in the two-phase interface, which is not conducive to improving the thermal conductivity of the polymer. The geometry of fillers and their dispersion in the matrix have a significant effect on the interface structure. In addition, there is a synergistic effect among the mixed heat conduction particles, which can form a thermal conduction pathway with isolated structure in the polymer matrix. The interface thermal resistance can be reduced effectively. In this paper, the effects of different morphologies of thermal conductivity particles, hybrid thermal conductivity particles and preparation process of thermal conductive composites on the thermal conductivity and thermal stability of UHMWPE were studied. The main contents and results are as follows: boron nitride / ultra-high molecular weight polyethylene (BN/UHMWPE), aluminum nitride / ultra-high molecular weight polyethylene (AlN/UHMWPE), () / ultrahigh molecular weight polyethylene (AlN/UHMWPE), () were successfully prepared by powder blending and hot pressing method. High molecular weight polyethylene (BN MWCNT) / UHMWPE) three kinds of composite materials. The study of thermal conductivity shows that the thermal conductivity of the composites increases with the increase of the filler content, and when the filler content is 50 wt%, the thermal conductivity of the composite increases with the increase of the filler content. The thermal conductivity of (BN MWCNT) / UHMWPEBN / UHMWPEBN / UHMWPEAlN / UHMWPEPE1.The thermal conductivity of (BN MWCNT) / UHMWPE is 1.505Wm-1 K-1, which is 64% higher than that of single filler BN/UHMWPE, which indicates that the synergistic effect between BN,MWCNT and UHMWPEB / UHMWPEAlPE is helpful to improve the thermal conductivity of UHMWPE. Scanning electron microscopy (SEM), (SEM), optical microscope (OM), atomic particle microscopy (OM),) (AFM) study showed that the BN sheet was entangled with MWCNT, and the thermal conduction network was denser than that of the pure BN,AlN composite. The results show that the thermal network and the interface at the boundary of different types of thermal conductive fillers have different effects on the thermal resistance of the interface and then on the thermal conductivity of the composites. Thermogravimetric (TGA) analysis shows that BN MWCNT has no obvious effect on the thermal stability of the composites, which is due to the formation of heat conduction pathways which can rapidly dissipate the heat generated in the matrix. The synergistic effect between flake BN and tubular MWCNT can effectively improve the thermal conductivity of composites. In addition, the microstructure and thermal conductivity of BN/UHMWPE, (BN MWCNT) / UHMWPE prepared by different temperature and pressure molding process were studied. The inner heat conduction network of composite prepared by cold pressing and calcining process is the most dense, but this network structure will be destroyed under the condition of high temperature and high pressure. Therefore, the thermal conductivity of the composites prepared by high temperature and high pressure process decreased. However, in (BN MWCNT) / UHMWPE composites, 1D-MWCNT entangled with 2D-BN to form a MWCNT-BN thermal network. The thermal conductivity of the UHMWPE filled with 50 wt% (BN MWCNT) hybrid filler is 1.761 Wm~ (-1) K ~ (-1) .TGA analysis shows that the thermal stability of the composite is influenced by the dispersion state of the filler in the matrix.
【學(xué)位授予單位】：西安理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O632.12;TB332
本文編號：2215933
[Abstract]:Polymer materials are widely used because of their light weight and low price. However, thermal insulation has limited their application in the field of microelectronics. How to improve the thermal conductivity of polymer materials has become a research hotspot in this field. The common way to improve the thermal conductivity of polymer is to add the thermal conductive particles to the polymer matrix by powder blending method, and the thermal conductivity particles cover the polymer to form an isolated structure. This heat conduction network structure is convenient for phonon transmission and makes it rapidly dissipate heat. However, the interfacial tension between the thermal conductive particles and the polymer matrix is large, it is difficult to combine effectively, and there are many defects in the two-phase interface, which is not conducive to improving the thermal conductivity of the polymer. The geometry of fillers and their dispersion in the matrix have a significant effect on the interface structure. In addition, there is a synergistic effect among the mixed heat conduction particles, which can form a thermal conduction pathway with isolated structure in the polymer matrix. The interface thermal resistance can be reduced effectively. In this paper, the effects of different morphologies of thermal conductivity particles, hybrid thermal conductivity particles and preparation process of thermal conductive composites on the thermal conductivity and thermal stability of UHMWPE were studied. The main contents and results are as follows: boron nitride / ultra-high molecular weight polyethylene (BN/UHMWPE), aluminum nitride / ultra-high molecular weight polyethylene (AlN/UHMWPE), () / ultrahigh molecular weight polyethylene (AlN/UHMWPE), () were successfully prepared by powder blending and hot pressing method. High molecular weight polyethylene (BN MWCNT) / UHMWPE) three kinds of composite materials. The study of thermal conductivity shows that the thermal conductivity of the composites increases with the increase of the filler content, and when the filler content is 50 wt%, the thermal conductivity of the composite increases with the increase of the filler content. The thermal conductivity of (BN MWCNT) / UHMWPEBN / UHMWPEBN / UHMWPEAlN / UHMWPEPE1.The thermal conductivity of (BN MWCNT) / UHMWPE is 1.505Wm-1 K-1, which is 64% higher than that of single filler BN/UHMWPE, which indicates that the synergistic effect between BN,MWCNT and UHMWPEB / UHMWPEAlPE is helpful to improve the thermal conductivity of UHMWPE. Scanning electron microscopy (SEM), (SEM), optical microscope (OM), atomic particle microscopy (OM),) (AFM) study showed that the BN sheet was entangled with MWCNT, and the thermal conduction network was denser than that of the pure BN,AlN composite. The results show that the thermal network and the interface at the boundary of different types of thermal conductive fillers have different effects on the thermal resistance of the interface and then on the thermal conductivity of the composites. Thermogravimetric (TGA) analysis shows that BN MWCNT has no obvious effect on the thermal stability of the composites, which is due to the formation of heat conduction pathways which can rapidly dissipate the heat generated in the matrix. The synergistic effect between flake BN and tubular MWCNT can effectively improve the thermal conductivity of composites. In addition, the microstructure and thermal conductivity of BN/UHMWPE, (BN MWCNT) / UHMWPE prepared by different temperature and pressure molding process were studied. The inner heat conduction network of composite prepared by cold pressing and calcining process is the most dense, but this network structure will be destroyed under the condition of high temperature and high pressure. Therefore, the thermal conductivity of the composites prepared by high temperature and high pressure process decreased. However, in (BN MWCNT) / UHMWPE composites, 1D-MWCNT entangled with 2D-BN to form a MWCNT-BN thermal network. The thermal conductivity of the UHMWPE filled with 50 wt% (BN MWCNT) hybrid filler is 1.761 Wm~ (-1) K ~ (-1) .TGA analysis shows that the thermal stability of the composite is influenced by the dispersion state of the filler in the matrix.
【學(xué)位授予單位】：西安理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O632.12;TB332
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