何思呈，王亞輝,黃　杰,錢心遠(yuǎn),廖　波

(1 麓山國(guó)際實(shí)驗(yàn)學(xué)校，湖南　長(zhǎng)沙　410006；2 株洲時(shí)代新材料科技股份有限公司，湖南　株洲　412007)

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含三稠環(huán)結(jié)構(gòu)聚酰亞胺的研究現(xiàn)狀

何思呈1，王亞輝2,黃杰2,錢心遠(yuǎn)2,廖波2

(1 麓山國(guó)際實(shí)驗(yàn)學(xué)校，湖南長(zhǎng)沙410006；2 株洲時(shí)代新材料科技股份有限公司，湖南株洲412007)

聚酰亞胺(PI)因其突出的熱性能和綜合性能，近年來(lái)在柔性有機(jī)電致發(fā)光器件(FOLED)封裝領(lǐng)域越來(lái)越受到重視。本文介紹了國(guó)內(nèi)外對(duì)含三稠環(huán)結(jié)構(gòu)聚酰亞胺的研究現(xiàn)狀；其中三稠環(huán)主要包括咔唑、芴、芴酮、二苯并呋喃和二苯并噻吩；詳細(xì)介紹了三稠環(huán)結(jié)構(gòu)對(duì)聚酰亞胺性能的影響；重點(diǎn)分析了三稠環(huán)結(jié)構(gòu)與聚酰亞胺的熱性能、溶解性能、光電性能的關(guān)系；展望了含三稠環(huán)結(jié)構(gòu)聚酰亞胺的發(fā)展。

三稠環(huán)；聚酰亞胺；熱性能

稠環(huán)化合物是兩個(gè)或兩個(gè)以上碳環(huán)或雜環(huán)以共有環(huán)邊而形成的多環(huán)有機(jī)化合物。所謂三稠環(huán)就是三個(gè)碳環(huán)或雜環(huán)以共有環(huán)邊而形成的三環(huán)有機(jī)化合物，常見(jiàn)的三稠環(huán)有：咔唑、芴、芴酮、二苯并呋喃和二苯并噻吩等，結(jié)構(gòu)式如圖1所示。

圖1　常見(jiàn)的三稠環(huán)Fig.1　Common three fused ring

20世紀(jì)60年代以來(lái)，隨著雜環(huán)聚合物研究的興起，以及對(duì)高性能聚合物的需求，在聚酰亞胺分子結(jié)構(gòu)中引入三稠環(huán)結(jié)構(gòu)的研究得以開(kāi)展。研究表明，三稠環(huán)結(jié)構(gòu)被引入到聚酰亞胺分子鏈中，可明顯提升聚酰亞胺的性能。在聚酰亞胺分子鏈中引入三稠環(huán)結(jié)構(gòu)主要有兩種方法，一種方法是通過(guò)合成帶有含三稠環(huán)結(jié)構(gòu)的單體進(jìn)行聚合反應(yīng)得到；另一種方法是先使用帶有可生成含三稠環(huán)結(jié)構(gòu)的反應(yīng)基團(tuán)的單體來(lái)制備聚酰胺酸前驅(qū)體，在酰亞胺化反應(yīng)完成后再轉(zhuǎn)化成相應(yīng)的含三稠環(huán)結(jié)構(gòu)。但是后一種方法因?yàn)樾枰叩臒崽幚頊囟榷鴷?huì)導(dǎo)致聚酰亞胺降解和致密性下降，而不容易獲得高性能的含三稠環(huán)結(jié)構(gòu)的聚酰亞胺。因此，合成含三稠環(huán)聚酰亞胺基本是使用第一種方法。

本文關(guān)注的主要是對(duì)聚酰亞胺性能提升較大的三稠環(huán)結(jié)構(gòu)(如：咔唑、芴、芴酮、二苯并呋喃和二苯并噻吩等)的引入對(duì)聚酰亞胺性能影響的研究。

1　含咔唑聚酰亞胺

咔唑是一種很重要的含氮原子芳雜環(huán)，具有特殊的剛性稠環(huán)結(jié)構(gòu)，其衍生物表現(xiàn)出許多獨(dú)特的光電性能。咔唑類化合物具有以下特點(diǎn)：(1)咔唑環(huán)易于形成相對(duì)穩(wěn)定的正離子；(2)分子內(nèi)具有較大的共軛體系及強(qiáng)的分子內(nèi)電子轉(zhuǎn)移；(3)一般具有較高的熱穩(wěn)定性和光化學(xué)穩(wěn)定性；(4)咔唑環(huán)上易于進(jìn)行結(jié)構(gòu)修飾引入多種官能團(tuán)。當(dāng)前設(shè)計(jì)合成含有咔唑或其衍生結(jié)構(gòu)的聚酰亞胺，主要是通過(guò)設(shè)計(jì)合成含咔唑結(jié)構(gòu)的二胺單體[1-8]，利用此二胺制備含咔唑結(jié)構(gòu)的聚酰亞胺，這些聚酰亞胺都具有良好的熱穩(wěn)定性、光電性能和優(yōu)異的存儲(chǔ)功能。目前，報(bào)道較多的都是側(cè)基含咔唑結(jié)構(gòu)的聚酰亞胺。

Mousa Ghaemy等[1]合成了一種含咔唑結(jié)構(gòu)二胺(DAC)，結(jié)構(gòu)式如圖2所示，并與多種二酐通過(guò)二步法制備了聚酰亞胺。咔唑基團(tuán)的引入使聚酰亞胺獲得良好的熱穩(wěn)定性。這些聚酰亞胺的10%的分解溫度范圍達(dá)到524～574 ℃。

圖2　含咔唑二胺(DAC)的結(jié)構(gòu)式Fig.2　Chemical structure of diamine containing carbazole(DAC)

Samdae Park等[2]合成了一種含咔唑結(jié)構(gòu)的二胺(HAB-CBZ)，結(jié)構(gòu)式如圖3所示，并與多種二酐聚合制備了聚酰亞胺。咔唑基團(tuán)的引入使聚酰亞胺獲得優(yōu)異的單極WORM存儲(chǔ)行為；同時(shí)，這些聚酰亞胺也具有良好的熱性能。Brian J. Ree[3]也利用此二胺做了類似的研究。Lei Shi等[4]合成了一種含咔唑結(jié)構(gòu)二胺(DACzTPA)，結(jié)構(gòu)式如圖4所示，與6FDA聚合制備了聚酰亞胺。咔唑基團(tuán)與三苯胺基團(tuán)作為供電子基團(tuán)，6FDA作為吸電子基團(tuán)，研究了聚酰亞胺的隨機(jī)靜態(tài)存儲(chǔ)行為。

圖3　含咔唑二胺(HAB-CBZ)的結(jié)構(gòu)式Fig.3　Chemical structure of diamine containing carbazole(HAB-CBZ)

圖4　含咔唑二胺(DACzTPA)的結(jié)構(gòu)式Fig.4　Chemical structure of diamine containing carbazole(DACzTPA)

Sheng-Huei Hsiao等[5]合成了一種含咔唑結(jié)構(gòu)的二胺，結(jié)構(gòu)式如圖5所示，并與多種二酐聚合制備了聚酰亞胺。含甲氧基的咔唑基團(tuán)的引入使聚酰亞胺獲得優(yōu)異的電化學(xué)穩(wěn)定性和電致變色性能，同時(shí)這些聚酰亞胺也具有良好的熱性能。

圖5　含咔唑二胺的結(jié)構(gòu)式Fig.5　Chemical structure of diamine containing carbazole

Ying-Chi Huang等[6]合成了一種含吡啶和咔唑結(jié)構(gòu)的二胺(CBAPP)，結(jié)構(gòu)式如圖6所示，并與多種二酐反應(yīng)制備了聚酰亞胺。由于雜環(huán)吡啶和咔唑結(jié)構(gòu)的引入，聚酰亞胺表現(xiàn)出良好的熱氧化穩(wěn)定性，優(yōu)異的機(jī)械性能和光學(xué)性能。

圖6　含咔唑二胺(CBAPP)的結(jié)構(gòu)式Fig.6　Chemical structure of diamine containing carbazole(CBAPP)

但關(guān)于在主鏈中引入咔唑結(jié)構(gòu)的聚酰亞胺只存在少量報(bào)道[9-12]。Xu Z K等[9-10]制備了一種主鏈含咔唑基團(tuán)的共聚聚酰亞胺，此聚酰亞胺表現(xiàn)出一定的光導(dǎo)電性能；Kotov B V等[11]也做了類似的研究。Biswas M[12]等合成了一系列含咔唑結(jié)構(gòu)的二胺，并與PMDA制備了一系列主鏈含咔唑結(jié)構(gòu)的聚酰亞胺。這些聚酰亞胺表現(xiàn)出優(yōu)異的熱性能和介電性能。主鏈含咔唑結(jié)構(gòu)聚酰亞胺的結(jié)構(gòu)式如圖7所示。

圖7　主鏈含咔唑環(huán)聚酰亞胺的結(jié)構(gòu)式Fig.7　Chemical structure of polyimide containing carbazole ring in backbone

2　含芴或芴酮聚酰亞胺

芴是一種常見(jiàn)三稠環(huán)，常見(jiàn)的衍生物為雙苯基芴。由于大的雙苯基芴結(jié)構(gòu)的存在，能夠賦予聚合物許多優(yōu)異特性[13]，例如：優(yōu)異的熱穩(wěn)定性；高的玻璃化轉(zhuǎn)變溫度；良好的有機(jī)溶劑溶解性；低介電常數(shù)；優(yōu)異的光電性能等。

正因?yàn)榇嬖谥T多優(yōu)異特性，含芴基聚酰亞胺近年來(lái)被研究的越來(lái)越多。當(dāng)前設(shè)計(jì)合成含有芴基或其衍生結(jié)構(gòu)的聚酰亞胺，主要是通過(guò)設(shè)計(jì)合成含芴基的二胺單體。含芴基聚酰亞胺由于在主鏈上帶有大的含芴側(cè)基，芴基的剛性較大，阻礙了聚酰亞胺分子鏈的纏結(jié)，減少了鏈的旋轉(zhuǎn)，降低了分子鏈堆砌密度，使其在氣體分離膜[14-16]、低介電材料[17-19]、燃料電池質(zhì)子傳輸膜[20-21]以及耐熱、可溶、易加工的聚酰亞胺材料[22-31]等領(lǐng)域得到研究和應(yīng)用。

Goto K等[19]制備了一系列含二苯基芴聚酰亞胺，并研究了其介電性能。如圖8所示的含二苯基芴聚酰亞胺，其介電常數(shù)為2.71。研究表明二苯基芴的引入可以阻礙聚酰亞胺分子鏈的纏結(jié)，減少聚合物鏈的旋轉(zhuǎn)，降低了分子鏈堆砌密度，聚合物具有較大的自由體積，從而使聚合物獲得低的介電常數(shù)。

圖8　二苯基芴聚酰亞胺的結(jié)構(gòu)式Fig.8　Chemical structure of polyimide containing diphenyl fluorine

Xiaoxia Guo等[20-21]合成了一種磺化的9,9-雙(4-氨基苯基)芴，并與商業(yè)化二酐合成了磺化聚酰亞胺，其具有較好的化學(xué)穩(wěn)定性，應(yīng)用于燃料電池質(zhì)子交換膜。新型二胺的結(jié)構(gòu)式如圖9所示。

圖9　二苯基芴聚酰亞胺的結(jié)構(gòu)式Fig.9　Chemical structure of polyimide containing diphenyl fluorine

Sillion等[22-24]合成了一種含芴結(jié)構(gòu)二胺9,9-雙(4-氨基苯基)芴及其聚酰亞胺，這些聚酰亞胺表現(xiàn)出了良好的熱性能、溶解性和低的吸水率。Teramoto等[25-27]使用含芴結(jié)構(gòu)二胺制備了耐熱可溶性聚酰亞胺和共聚聚酰亞胺。Ayukawa等[28]合成了一系列可熱固化的含芴結(jié)構(gòu)聚酰亞胺。Connell等[29]合成了苯乙炔基封端含芴結(jié)構(gòu)聚酰亞胺齊聚物，用于樹(shù)脂傳遞模塑用樹(shù)脂。Hsiao等[30]合成了芴基二醚二酐，并與不同二胺反應(yīng)得到了可溶性聚醚酰亞胺。Yang等[31]也由芴基二醚二胺與不同結(jié)構(gòu)的二酐合成得到了一系列可溶性聚酰亞胺。

但關(guān)于在主鏈中引入含芴基團(tuán)的聚酰亞胺報(bào)道較少[32]。Bell Vernon L[32]合成了一系列含芴或芴酮二胺，結(jié)構(gòu)如圖10所示，并與BTDA和PMDA聚合制備聚酰亞胺。由于這些聚酰亞胺分子鏈中含有大量苯環(huán)，剛性極大，具有優(yōu)異的熱穩(wěn)定性。

圖10　含芴或芴酮單元二胺的結(jié)構(gòu)式Fig.10　Chemical structure of diamine containing fluorene or fluorenone

3　含二苯并噻吩和二苯并呋喃聚酰亞胺

二苯并噻吩和二苯并呋喃性質(zhì)相似，都是一種具有芳香性的良好的電子給體，容易形成D-π-D或A-π-A體系，具有高電子密度和良好的剛性結(jié)構(gòu)。近年來(lái)含二苯并噻吩和二苯并呋喃聚酰亞胺已有少量報(bào)道[33-35]。

Alain Tundidor-Camba等[33]制備了一種含二苯并呋喃結(jié)構(gòu)的新型二胺(2,8-Di(3-aminophenyl)dibenzofuran)，與BTDA、6FDA、SiDA聚合得到了三種PI。由于剛性結(jié)構(gòu)二苯并呋喃結(jié)構(gòu)的引入，三種PI都顯示出良好的熱性能。(2,8-Di(3-aminophenyl)dibenzofuran)的結(jié)構(gòu)式如圖11所示。

圖11　含二苯并呋喃二胺的結(jié)構(gòu)式Fig.11　Chemical structure of diamine containing dibenzofuran

Matsumoto T等[34]合成了兩種含二苯并呋喃結(jié)構(gòu)的二胺及其聚酰亞胺，二胺的化學(xué)結(jié)構(gòu)如圖12所示。由于聚酰亞胺分子主鏈中含有二苯并呋喃結(jié)構(gòu)，導(dǎo)致聚酰亞胺具有優(yōu)異的熱穩(wěn)定性和力學(xué)性能。

圖12　含二苯并呋喃二胺的結(jié)構(gòu)式Fig.12　Chemical structure of diamine containing dibenzofuran

Cheng-Liang Liu等[35]合成了兩種含二苯并噻吩結(jié)構(gòu)的新型二胺(2,8-APDBT和3,7-APDBT)，并與6FDA反應(yīng)制備了兩種聚酰亞胺。二苯并噻吩結(jié)構(gòu)作為聚酰亞胺中的電子供體，鄰苯二甲酰亞胺作為電子受體，使其體現(xiàn)出優(yōu)異的存儲(chǔ)性能。2,8-APDBT和3,7-APDBT的結(jié)構(gòu)如圖13所示。

圖13　含二苯并噻吩和二苯并呋喃的二胺的結(jié)構(gòu)式Fig.13　Chemical structure of diamine containing dibenzothiophene and dibenzofuran

4　展　望

聚酰亞胺優(yōu)異的綜合性能使其在微電子、光電子等高新技術(shù)領(lǐng)域發(fā)揮著越來(lái)越重要的作用。隨著我國(guó)經(jīng)濟(jì)蓬勃發(fā)展，市場(chǎng)對(duì)高性能聚酰亞胺的需求越來(lái)越大，綜合考慮多種因素對(duì)聚酰亞胺結(jié)構(gòu)進(jìn)行設(shè)計(jì)，使其在不降低聚酰亞胺原有的良好熱性能和力學(xué)性能的前提下，提升聚酰亞胺其他性能。含三稠環(huán)結(jié)構(gòu)聚酰亞胺具有優(yōu)異的綜合性能，為開(kāi)發(fā)高性能、低成本的聚酰亞胺提供發(fā)展方向。因此對(duì)于含三稠環(huán)結(jié)構(gòu)聚酰亞胺的研究還是很有意義的。

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Research Status of Polyimide Containing Three Fused Ring Structure

HESi-cheng1,WANGYa-hui2,HUANGJie2,QIANXin-yuan2,LIAOBo2

(1 Lushan International Experimental School, Hunan Changsha 410006;2 Zhuzhou Times New Material Technology Co., Ltd., Hunan Zhuzhou 412007, China)

In recent years, polyimide(PI) has attracted more and more attention in the field of flexible Organic Light-Emitting Diode (FOLED) package due to its outstanding thermal performance and comprehensive performance. The research status of polyimide containing three fused ring structure at home and abroad was introduced, three fused ring mainly included carbazole and fluorene fluorenone, dibenzofuran and dibenzothiophene. The effects of three fused ring structure on the properties of polyimide were introduced in detail, the relationship between the thermal properties, the solubility and the photoelectric properties of polyimide containing three fused ring structure were mostly analyzed, the development of polyimide containing three fused ring structure was discussed.

three fused ring; polyimide; thermal property

O631.2

A

1001-9677(2016)018-0023-04