動(dòng)態(tài)力學(xué)性能和介電性能
(中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 依次用混強(qiáng)酸和SOCl2對(duì)多壁碳納米管(MWNTs)進(jìn)行改性，解決其在有機(jī)溶劑的溶解性和在基體聚酰亞胺中分散性問題，并采用光電子能譜(XPS)和透射電鏡(TEM)對(duì)改性前后的MWNTs進(jìn)行表征。以4,4’−二氨基二苯醚(ODA)和3,3’,4,4’−二苯甲酮四羧酸二酐(BTDA)為原料，以原位聚合法將改性碳納米管摻雜聚酰亞胺(PI)，制備MWNTs/PI納米復(fù)合材料。通過熱重分析( TGA)、動(dòng)態(tài)力學(xué)分析(DMA)和電容測(cè)試對(duì)材料的熱性能、動(dòng)態(tài)力學(xué)和介電性能進(jìn)行表征。結(jié)果表明：加入MWNTs后，材料仍有很好的熱穩(wěn)定性，材料的動(dòng)態(tài)力學(xué)性能隨MWNTs增加而增強(qiáng)，在50 ℃和10% (質(zhì)量分?jǐn)?shù))MWNTs時(shí)儲(chǔ)能模量為2.307 GPa,比純聚酰亞胺(PI)提高23.1%；材料的介電常數(shù)隨著MWNTs含量的增加明顯提高，在1MHz和10%時(shí)介電常數(shù)為66.7，是純PI的18.6倍。制備的碳納米管/聚酰亞胺材料是一種具有優(yōu)良的熱學(xué)、動(dòng)態(tài)力學(xué)力學(xué)和介電性能性能的納米復(fù)合材料。
關(guān)鍵字: 聚酰亞胺；多壁碳納米管；動(dòng)態(tài)力學(xué)性能；介電性能
their dynamic mechanical properties and dielectric properties
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The multi-walled carbon nanotubes (MWNTs) were modified by mixed strong acids and sulfuryl dichloride (SOCl2) successively. Their solubility in organic solvents and dispersivity in matrix of polyimides were improved greatly by modification. The unmodified and modified MWNTs were characterized by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The polyimide (PI)/MWNTs composites were synthesized by in situ polymerization of 4,4’-diaminodiphenylether (ODA) and 3,3’,4,4’-benzophenonetetracarboxylic dianhydride (BTDA), in which the modified MWNTs were used as the fillers. The composites were characterized by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and measurement of capacitance. The results show that the PI/MWNTs composites have preferable heat stability as the same as the pure polyimide (PI). The dynamic mechanical properties improve with the mass fraction of MWNTs increasing. The value of storage modulus is 2.03 GPa at 50 ℃ when the mass fraction of MWNTs is 10%. Compared with that of the pure PI, the storage modulus increases by 23.1%. The dielectric properties enhance sharply with the mass fraction of MWNTs increasing. For the nanocomposites containing 10% of MWNTs, the dielectric constant reaches 66.7 at 1 MHz, which comes up to 18.6 times of that of pure polyimide. Therefore, The MWNTs/PI is a kind of nanocomposite material with favorable properties of thermal properties, dynamic mechanical properties and dielectric properties.
Key words: polyimide; multi-walled carbon nanotubes; dynamic mechanical properties; dielectric properties
