含氟聚酰亚胺的设计、合成及应用性能研究进展

聚酰亚胺作为结构独特的一类功能性高分子材料,应用广泛。随着人们对材料综合性能要求的提高,含氟聚酰亚胺颇受业界关注。聚酰亚胺结构中引入氟原子既能提高材料溶解性和透光率,还能降低其吸湿率和介电常数。综述了近年来含氟聚酰亚胺在设计、合成和应用性能方面的研究进展,指出其结构设计带来的性能优势。特别是对含氟聚酰亚胺的溶解性、光学性能、热性能等进行了总结。展望了其在柔性显示面板/基板市场的应用发展方向。     

含氟聚酰亚胺的设计、合成及应用性能研究进展

聚酰亚胺作为结构独特的一类功能性高分子材料,应用广泛.随着人们对材料综合性能要求的提高,含氟聚酰亚胺颇受业界关注.聚酰亚胺结构中引入氟原子既能提高材料溶解性和透光率,还能降低其吸湿率和介电常数.综述了近年来含氟聚酰亚胺在设计、合成和应用性能方面的研究进展,指出其结构设计带来的性能优势.特别是对含氟聚酰亚胺的溶解性、光学性能、热性能等进行了总结.展望了其在柔性显示面板/基板市场的应用发展方向.     

含氟嵌段聚酰亚胺共聚物的制备及其介电常数计算

通过顺序加料法制备了一系列不同氟含量聚酰亚胺,FT-IR、1H-NMR及GPC测试结果表明,所制备的聚合物为嵌段共聚物.Lorenz和Vogel介电常数计算公式主要用于均聚物介电常数的计算,通过对上述两计算公式进行相应变形处理,使之适用于计算嵌段共聚物的理论介电常数,并将其运用到所合成的嵌段型含氟聚酰亚胺模板聚合物的介电常数计算中,计算结果显示,Lorenz和Vogel介电常数变形公式计算所得的模板聚合物的介电常数与聚合物介电常数实测值具有较好的吻合性,能够有效指导低介电常数嵌段聚酰亚胺的设计与合成.     

四氟化碳等离子体处理对聚酰亚胺介电性能的影响

采用等离子体活化的方法,使用四氟化碳（CF4）气体,对印刷线路板常用基材聚酰亚胺薄膜进行了处理,将含氟基团引入到聚酰亚胺薄膜表面。通过测量材料表面的接触角、x射线光电子能谱分析等,验证了通过等离子体处理,含氟基团成功引入了聚酰亚胺薄膜表面。通过改变等离子体处理的功率及反应时间,研究了不同处理条件对聚酰亚胺薄膜介电常数和介电损耗的影响。结果显示：随着处理功率和处理时间的增加,聚酰亚胺薄膜的介电常数和介电损耗在低频区域有显著的降低（频率范围1～100Hz）。在最优条件下,聚酰亚胺薄膜的介电常数从平均2．7降至平均1．9（频率范围1～100Hz）,介电损耗正切值从平均0．145降至平均0．06左右（频率范围1～100Hz）。     

低介电常数聚酰亚胺薄膜研究进展

依据国内外低介电常数聚酰亚胺（PI）薄膜材料的专利研究情况,综述了近年来低介电常数PI薄膜的制备方法,包括引入含氟取代基、脂环结构、嵌段结构、微孔结构、无机杂化材料等方法制备低介电常数材料。同时,对低介电常数PI薄膜的研究趋势进行了展望。     

含氟聚酰亚胺的研究及其在涂料中的应用

介绍了含氟聚酰亚胺的分类和研究动向,重点介绍了含三氟甲基及六氟丙基的聚酰亚胺的特点和性能。阐述了含氟聚酰亚胺在绝缘涂料中的应用,并对含氟聚酰亚胺在光电材料、复合材料和气体分离膜等领域中的应用进行了概述。     

生产含氟聚酰亚胺膜的方法和设备

提供一种生产具有突出的耐热性、耐化学药品性、防水性、绝缘性、电性能和光学性能的含氟聚酰亚胺膜的方法和适用于该方法的旋转涂布机。提供一种生产聚酰亚胺膜的方法,该方法包括在将相对湿度调至不大于50RH％的气氛中使含氟聚酰亚胺前体形成涂布膜,然后对该含氟聚酰亚胺前体进行热处理从而形成含氟聚酰亚胺膜。按照该方法,     

含氟聚酰亚胺的研究进展

含氟聚酰亚胺是一类重要的高性能聚合物材料,因其突出的物理化学性质、光学和电学性能以及气体选择透过性等被广泛应用于电子工业、光波通讯、航空航天以及气体分离材料等领域。文章着重介绍了含氟聚酰亚胺的研究进展,同时简述含氟聚酰亚胺结构性能及应用。     

聚酰亚胺/无机纳米粒子复合材料在介电领域应用

传统的聚酰亚胺材料的介电常数范围通常在3. 0～3. 6之间,是电子电工领域应用较多的绝缘介质材料。随着相关行业技术的不断发展,对聚酰亚胺材料的要求也越来越高。目前,具有高介电常数的聚酰亚胺复合材料薄膜正越来越多地被人们研究。通过向聚酰亚胺体系内加入不同类型的无机纳米粒子,可以不同程度低提高聚酰亚胺体系的介电常数。本文列举了不同类型无机纳米粒子掺杂的聚酰亚胺复合材料的制备及表征工作,并对其应用进行了展望。     

含氟聚酰亚胺的合成及性能研究进展

介绍了含氟聚酰亚胺的性能、分类、制备原料、通用制备方法及应用。综述了近年来含氟聚酰亚胺的合成及性能研究进展情况。     

Studies of dielectric characteristics and surface energies of spin‐coated polyimide films

A two‐step method, that is, polyamic acid formation with subsequent curing, was used to synthesize six kinds of polyimides. Dielectric constants and surface energies were investigated to determine the nature of the fluorinated and nonfluorinated polyimides. The dielectric constant decreased from 3.3 (at 100 kHz) for PMDA/ODA to 2.6 (at 100 kHz) for 6FDA/4,4′‐6F when the fluorine content increased from 0 to 30.7 wt %. Simultaneously, the water contact angle increased from 65° for PMDA/ODA to 78° for 6FDA/4,4′‐6F. Experimental results indicated that fluorinated polyimides contained a lower dielectric constant with improved water resistance. The surface energy values obtained from experiments agreed well with Holmes' correlation between surface energy and dielectric constant. The surface energies and dielectric constants were significantly affected by the polymer backbone structures, especially by the fluorination effect. Therefore, by choosing the appropriate monomers, polyimides of low dielectric constants with hydrophobic surfaces could be obtained. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1642–1652, 2001     

Inclusion of covalent triazine framework into fluorinated polyimides to obtain composites with low dielectric constant

Polyimides possess good mechanical properties, favorable dielectric properties, and chemical inertness, which enabled them to find applications in microelectronic industries. The dielectric constant of the polyimides varies between 2.5 and 4, which is rather high for such applications. Hence, synthesizing polyimides with still lower dielectric constant has become one of the critical research confronts. As the properties of a terpolyimides (TPI) could be altered as per the requirement, it was synthesized by combining the dianhydrides 3,3′,4,4′-biphenyldianhydride, 3,3′,4,4′-oxydiphthalicdianhydride, and 4,4′-(hexafluoroisopropylidene) with a diamine 4,4′-(hexafluoroisopropylidene)dianiline or 2,2-bis[4-(4-amino phenoxy)phenyl]hexafluoropropane. As porous covalent triazine framework (CTF-1) is capable of capturing much air within its pores and interfacial voids, it was combined with the TPI matrix in different loadings to obtain CTF-1/TPI composite films with low dielectric constant. The composites exhibited high thermal stability, as their thermal decomposition occurred above 520°C. The tensile properties and the dielectric constant of the composites declined with the raise in CTF-1 loading up to 4%. The decrease in dielectric constant is essentially due to the incorporation of air voids (dielectric constant of air ~1) in the TPI matrix due to the inclusion of porous CTF-1.     

Relationship between gas transport properties and fractional free volume determined from dielectric constant in polyimide films containing the hexafluoroisopropylidene group

The dielectric constant and gas transport properties (i.e., permeability, diffusivity, and solubility) in 2,2′‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride (6FDA)‐based polyimides were systematically investigated in terms of their polymer fractional free volumes (FFVs) at 30°C. The permeability and diffusion coefficients of the 6FDA‐based polyimide films to hydrogen, oxygen, nitrogen, methane, and carbon dioxide were correlated with their FFVs estimated using van Krevelen's group contribution method. There appeared, however, small linear correlation coefficients. Linear correlations were also observed between the gas transport properties and dielectric constant of these polyimides. This study described FFVas a function of the dielectric constant based on the Clausius‐Mossotti equation. It was found that the gas permeability and diffusion coefficients of these 6FDA‐based polyimide films increased as their dielectric constant‐based FFV increased. A better linear relationship was observed between the gas transport properties and the FFV determined from the polymer dielectric constant in comparison to that estimated using the group contribution method. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Incorporation of COF‐LZU‐1 into the terpolyimide matrix to obtain COF‐LZU‐1/terpolyimide composites with ultra‐low dielectric constant

Polyimides are used in microelectronics as they possess the essential high tensile properties, high thermal stability and low dielectric constant. As the further reduction in their dielectric constant is indispensable for such applications, in this study it was loaded with the porous covalent organic framework (COF‐LZU‐1) to obtain COF‐LZU‐1/terpolyimide composites. The composites can capture much air (κ = 1) in their matrix and bring down the dielectric constant below the virgin polyimides. In the beginning, the terpoly(amic acid)s were prepared, then loaded with the COF‐LZU‐1, and subsequently, stage cured up to 350°C to obtain COF‐LZU‐1/terpolyimide composites. Their thermal degradation occurred close to 530°C, illustrating high thermal stability. Their dielectric constant decreased with an increase in the COF‐LZU‐1 loading from 1 to 4%. The lowest dielectric constant of 1.36 was obtained with 4% loading. So, COF‐LZU‐1 and different polyimides can be suitably combined to obtain composites with desirable characteristics for applications in microelectronics. POLYM. ENG. SCI., 59:814–820, 2019. © 2018 Society of Plastics Engineers     

Synthesis and characterization of polyimides from bis(3-aminophenyl)-2,3,5,6-tetrafluoro-4-trifluoromethylphenyl phosphine oxide (mDA7FPPO)

A novel diamine, bis(3-aminophenyl)-2,3,5,6-tetrafluoro-4-trifluoromethylphenyl phosphine oxide (mDA7FPPO), was synthesized via Grignard reaction, followed by nitration and reduction. The monomer was characterized by FT-IR, NMR and melting point apparatus, and utilized to prepare polyimides with 6FDA, BTDA or ODPA via a conventional two-step synthesis; preparation of poly(amic acid), followed by solution imidization. The molecular weight of polyimides was controlled to 20,000 g/mol by off-stoichiometry and the polyimides were characterized by FT-IR, NMR, GPC, TGA and DSC. Solubility, intrinsic viscosity, dielectric constant and refractive index were also evaluated. The novel polyimides exhibited high T_g (229-252 °C), excellent thermal stability (>500 °C), low dielectric constant (2.65-2.81) and low birefringence (0.0019-0.0049).     

Synthesis and properties of fluorinated polyimides and fluorinated poly(imide amide)s containing pendent cyano groups

A series of fluorinated polyimides and fluorinated poly(imide amide)s containing pendent cyano groups were prepared and investigated to determine their dielectric constants as a function of relative humidity and thermal characteristics. The fluorinated polymides and fluorinated poly(imide amide)s containing pendent cyano groups were prepared by reaction of bis(4-aminophenoxy) benzonitriles with a fluorinated dianhydride and with a fluorinated di(acid chloride) containing preformed imide rings. The properties of the fluorinated polyimides and fluorinated poly(imide amide)s containing pendent cyano groups were compared with those of fluorinated polyimides and fluorinated poly(imide amide)s prepared from 1,3-bis(4-aminophenoxy)benzene. The introduction of the pendent cyano groups caused an increase in the dielectric constant and an increase in the glass transition temperature of the polymers compared with the polymers prepared without pendent cyano groups.     

High-temperature polyimide nanofoams for microelectronic applications

Foamed polyimides have been developed in order to obtain thin film dielectric layers with very low dielectric constants for use in microelectronic devices. In these systems the pore sizes are in the nanometer range, thus, the term ‘nanofoam’. The polyimide foams are prepared from block copolymers consisting of thermally stable and thermally labile blocks, the latter being the dispersed phase. Foam formation is effected by thermolysis of the thermally labile block, leaving pores of the size and shape corresponding to the initial copolymer morphology. Nanofoams prepared from a number of polyimides as matrix materials were investigated as well as from a number of thermally labile polymers. The foams were characterized by a variety of experiments including TEM, SAXS, WAXD, DMTA, density measurements, refractive index measurements and dielectric constant measurements. Thin film foams, with high thermal stability and low dielectric constants approaching 2.0, can be prepared using the copolymer/nanofoam approach.     

Intrinsically photosensitive polyimides: Approaches to fluorinated homologs

Cyclobutane tetracarboxylic acid dianhydrides, which were prepared via photodimerization of maleic anhydride or methylmaleic anhydride, gave high molecular weight film-forming polyimides with oxydianiline. The resulting polyimides were found to be photosensitive, presumably because of retrocyclization of the cyclobutane ring. Despite the presence of the cyclobutane ring, the polyimides show good thermal stability. In an effort to enhance the thermal stability and lower the dielectric constant of these polyimides, an approach was made to prepare the fluorinated analogs of the cyclobutane dianhydride monomers via the preparation and photodimerization of fluorinated maleic anhydride derivatives. Thus, both fluoromaleic and difluoromaleic anhydrides were photolyzed to give the target monomers. The proposed application of these monomers, however, has yielded disappointing results due to complications in their synthesis and attempted polymerization.