Preparation and characterization of photoreactive copolymers containing curable pendants for positive photoresist

tert‐Butyl methacrylate (TBMA) was copolymerized with various comonomers that were selected from methyl methacrylate (MMA), n‐butyl acrylate (NBA), acrylic acid (AA), and 2‐hydroxyethyl methacrylate (HEMA). From film physical properties, poly(TBMA‐co‐HEMA) and poly(TBMA‐co‐AA‐co‐NBA), were selected as resin binders. To introduce unsaturated double bonds onto the side chain of copolymers, they were further functionalized with acryloyl chloride and glycidyl methacrylate. Copolymers synthesized in this investigation were all identified by using FTIR and NMR. The thermal decomposition temperature of functionalized poly(TBMA‐co‐HEMA) showed obvious difference before and after crosslinking. Adding a small amount of EGDMA as the crosslinking agent could increase the degree of crosslinking and obviously improve the physical properties. Functionalized poly(TBMA‐co‐HEMA) was used as a binder resin and composed with a photoacid generator for positive photoresists. From exposure characteristics, the optimal lithographic condition was achieved when exposed for 90 s, PEB at 100°C for 2.5 min, and developed in 10 wt % Na₂CO₃ developer for 30 s. After completing the lithography process, the residual pattern of positive photoresist was further treated at 140°C for 30 min to cure the pendant unsaturated groups. The resolution of the positive photoresist was analyzed by an optical microscope and SEM technique. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 328–333, 2001     

系列聚酰亚胺的制备及其结构表征

以二苯醚四羧酸二酐（0DPA）为二酐单体,对苯二胺（PDA）和二胺基二苯基醚（ODA）为二胺单体,通过低温缩聚合成一系列聚酰胺酸（PAA）和聚酰亚胺（PI）薄膜,对其结构和力学性能进行表征,并比较ODPA—PDA和ODPA—ODA薄膜的力学性能。结果表明,PAA的酰亚胺化较完全;链节元素组成与空间构型对于PAA与PI薄膜的力学性能影响较大,其中,PI（ODPA—PDA）薄膜的拉伸强度达到450MPa。     

Preparation and characterization of soluble polyimides

Two kinds of soluble polyimides from pyromellitic dianhydride with Congo red and 4-sulfanilamide were prepared, respectively. Their structures were characterized by IR and ¹H-NMR, and the thermal properties were investigated by DSC and TG–DTA. © 1995 John Wiley & Sons, Inc.     

Preparation of negative photoreactive polyimide and its characterization

In this article, a polyimide precursor was synthesized from oxydianiline and a diacid chloride. This diacid chloride was prepared by the reaction of thionyl chloride with a diacid, which resulted from the reaction of pyromellitic dianhydride with cinnamyl alcohol in N-methylpyrrolidone (NMP). The photoresist, made from the above polyimide precursor, was spincoated onto silicon wafers, prebaked, and then exposed to UV light with a high pressure Hg lamp. The pattern generation process was also investigated. The appropriate conditions of the photolithographic procedures, involving photoresist compounding, spin coating, prebaking, exposure, development, rinse, postbaking, etc., were determined. The experimental results show that the photoresist exhibited excellent thermal stability and adequate photosensitivity.     

Preparation and characterization of aromatic polyimides and related copolymers

Copolyimides containing BTDA-3DDS and BTDA-4ODA units have been synthesized by solution imidization methods. The copolyimides have high T_g's (267–283°C) and high decomposition temperatures (540–575°C; nitrogen); both properties are dependent on composition. Those copolymides with low concentrations of BTDA-4ODA are generally soluble in organic solvents, whereas those copolyimides with higher BTDA-4ODA content are only partially soluble or insoluble. However, all the copolyimides prepared can be compression molded. It has also been found that segmental motion above T_g is heavily suppressed in the BTDA-4ODA homopolymer relative to that in the BTDA-3DDS homopolymer. This reduction in molecular motion may severely hinder the solubility and fusibility of the BTDA-4ODA homopolymer. © 1993 John Wiley & Sons, Inc.     

Preparation and characterization of metal‐containing aromatic polyimides

A series of novel metal‐containing aromatic polyimides were synthesized from divalent metal oxide/hydroxide (MO/M(OH)₂) (M = Ba, Sr, Ca, Mg, Zn, Cd, Co, Ni, Pb, Cu), p‐aniline sulfonic acid (ASA), and 3,3′‐4,4′‐benzophenonetetracarboxylic dianhydride (BTDA). The C, H, N, and S contents were determined by elemental analysis, their structures were characterized by proton nuclear magnetic resonance (¹H‐NMR) and Fourier transform infrared (FT‐IR) spectroscopy, and the thermal properties of the polymers were also studied by TG–DTA. It is found that metal‐containing polyimides have a higher thermal stability. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2363–2369, 2000     

长链聚酰亚胺的制备与表征

以长链二胺4,4' 二(4 氨基苯氧基)二苯砜(BAPS)为单体,采用两步法分别与二酐PMDA、ODPA、BPADA合成了3种链长的聚酰亚胺。实验利用GPC监测0 05mol/L聚酰胺酸(PAA)的数均聚合度(Xn)及相对分子质量分布随缩聚时间的变化关系,结果表明该反应为一逐步缩聚反应,缩聚速率随二酐电子亲和性(EA)的递增而增加;与预聚体聚酰胺酸相比,热处理环化得到聚酰亚胺其数均分子质量( Mn)和特性粘度[η]均有所下降,而分布指数(D)增大。此外还利用红外光谱(FTIR)、差分扫描量热法(DSC)、热重分析(TGA)等对聚酰亚胺进行了表征,结果表明聚酰亚胺(PI)的玻璃化温度(tg)和热分解温度(td)随着聚合单元长度的增加而降低。     

Preparation and fabrication of aromatic polyimides

Aromatic polyimides were prepared from pyromellitic dianhydride and a number of aromatic diamines. The effect of certain variables on the polymerization to, and the degradation of, the intermediate polypyromellitamic acids was studied, and a previously unrecorded reaction intermediate was isolated and identified. From these studies the conditions necessary to obtain high molecular weights were defined. Techniques were developed for the fabrication of satisfactory films and moldings.     

Synthesis and characterization of end‐capped polyimides and their gas permeability properties

Polyimides (PIs) based on 3,3′,4,4′‐oxydiphthalic anhydride (ODPA) and 4,4′‐oxydianiline (ODA) end capped with two new monoamines and other four different monoamines have been synthesized with a view to study the effect of different functional groups at the end of polymer chain on solubility, gas permeability, and thermal properties. The new monoamines have been synthesized from 3‐pentadecylphenol, obtained by hydrogenation of cardanol, a major constituent of cashew‐nut shell liquid. Introduction of different functional groups at the end of polyimide (PI) based on ODPA and ODA, by end capping with different monoamines, alters oxygen and nitrogen gas permeability, solubility, and thermal properties. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 627–635, 2000     

Synthesis and characterization of some aromatic polyimides

The diamine 2‐methyl‐1,3‐bis(4‐aminophenyloxy)benzene was prepared via a nucleophilic substitution reaction and was characterized with Fourier transform infrared, elemental analysis, and ¹H‐ and ¹³C‐NMR spectroscopy. The prepared diamine was also characterized with single‐crystal analysis. The geometric parameters of C₁₉H₁₈N₂O₂ were in the usual ranges. The dihedral angles between the central phenyl ring and the two terminal aromatic rings were 88.9 and 91.6°. The crystal structure was stabilized by N? H···N hydrogen bonds. The diamine was then polymerized with 3,3′,4,4′‐benzophenone tetracarboxylic acid dianhydride, 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, 3,4,9,10‐perylenetetracarboxylic acid dianhydride, and pyromellitic dianhydride by either a one‐step solution polymerization reaction or a two‐step procedure. These polymers had inherent viscosities ranging from 0.61 to 0.85 dL/gm. Some of the polymers were soluble in most common organic solvents even at room temperature, and some were soluble on heating. The degradation temperatures of the resultant polymers fell in the range of 260–500°C in nitrogen (with only 10% weight loss). The specific heat capacity at 200°C ranged from 1.0 to 2.21 J g^?1 K^?1. The temperatures at which the maximum degradation of the polymer occurred ranged from 510 to 610°C. The glass‐transition temperatures of the polyimides ranged from 182 to 191°C. The activation energy and enthalpy of the polyimides ranged from 44.44 to 73.91 kJ/mol and from 42.58 to 72.08 kJ/mol K, respectively. The moisture absorption was found in the range of 0.23–0.71%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

杂环型聚酰亚胺的合成与性能比较

利用含有醚、酮及砜基官能团的二胺、二酐单体通过二步法合成了几种不同结构的聚酰亚胺。并应用FT-IR、TGA、DSC、X-Ray等测试方法,对所得聚酰亚胺树脂的性能进行测试与比较。结果表明,不同官能团对聚酰亚胺的性能影响极为不同,醚酮类聚酰亚胺能够在保持其热性能的前提下在一定程度上改善其溶解性,而含砜基聚酰亚胺则能极大地改善溶解性。应当根据具体应用对聚酰亚胺的种类进行选择。     

Preparation and characterization of inherently heat‐sealable polyimides with high glass transition temperatures

A series of inherently heat‐sealable copolyimides (CPIs) with high glass transition temperatures were synthesized from 2,3,3′,4′‐oxydiphthalic anhydride (aODPA) and bicomponent diamines, 4,4′‐oxydianiline (ODA) and para‐phenylenediamine (PDA). The PI chain rigidity was manipulated by the regulation of the diamine ratio, and its effects on the heat sealability and thermal resistance of the derived CPI films were investigated in detail. The results show that these films are in possession of both good heat sealability and thermal resistance due to the synergetic effect of the asymmetry of aODPA and the rigidity of PDA. It is also found that there exists one critical PDA content that distinguishes the heat‐sealing behaviors of the CPI films, and the relevant mechanism was established. Especially for CPI‐5, the heat‐sealing strength is up to 350 N m^?1 simultaneously with a relatively high T_g of 310°C. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43058.     

Synthesis,characterization of phosphine oxide-containing polyimides and their use as selective membrane for dopamine

Tris-(p-aminophenoxy)phosphineoxide, t-APPO, was prepared from 4-nitrophenol and POCl₃, followed by hydrogenation. A series of polyimides prepared from t-APPO and the corresponding dianhydrides by two-stage polycondensation method was characterized by Fourier Transform Infrared Spectrometer (FTIR), GPC, thermal analysis and physical methods. Moreover, in order to check the permeation properties of the resulting polyimide film, the selectivity of the polyimide-coated electrode toward electroactive species (ascorbic acid and dopamine) was examined by means of cyclic voltammetry (CV), differential pulse voltammetry (DPV) and time-base amperometric measurement (TB) techniques. As a result, it has been found that polyimide electrode showed selective permeation for dopamine while blocking the permeation of ascorbic acid through film. Therefore, it has been claimed that phosphine oxide-containing polyimide electrode can be used as a dopamine-selective membrane in the presence of ascorbic acid.     

Synthesis and characterization of polyimides containing pyridine moiety

A series of new polyimides was prepared by reacting 2,6‐diaminopyridine with various aromatic dianhydrides in DMF in 1 : 1 mole ratio. All the resulting polyimides were readily soluble in organic solvents such as dimethylformamide, N,N‐dimethylacetamide, pyridine, m‐cresol, THF, etc. They also show good film‐forming ability. The polyimides exhibit good thermal stability and mechanical properties. The polymers have high T_g in the range of 252–296°C. The inherent viscosities of the polymers vary from 0.81 to 1.28 dL/g. A new class of bismaleimide and polyaspartimide as also synthesized. All the resulting polymer structures were characterized by FTIR and elemental analysis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1846–1853, 2004     

Preparation and characterization of polyimide‐g‐nylon 6 copolymers from nonfunctionalized polyimides

In this research, the anionic polymerization of ?‐caprolactam was carried out in the presence of small amounts of several different polyimides to generate polyimide‐g‐nylon 6 copolymers. The polyimides, which were prepared from 2,2′‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]propane dianhydride and commercially available diamines with a one‐step method, were first dissolved in molten ?‐caprolactam. Phenylmagnesium bromide was then added at 120°C. Under these conditions, caprolactam anions were formed that attacked the five‐membered imide rings to form N‐acyllactam moieties, which activated the anionic polymerization of caprolactam. In essence, nylon 6 chains grew from the polyimide backbones. Probably because of a high activation energy, the process was relatively slow, requiring 1 h at 120°C. The introduction of 5 wt % polyimide into the graft copolymers produced significant increases in the tensile modulus and tensile strength in comparison with those of low‐ and high‐molecular‐weight nylon 6. The elongation to break, however, was reduced. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 292–299, 2006     

Preparation of soluble polyimides and ultrafiltration membrane performances

Various soluble polyimides with bis[4‐(3‐aminophenoxy)phenyl]sulfone and three kinds of dianhydrides were prepared in a polar N‐methyl‐2‐pyrrolidone solvent by the traditional chemical two‐step method. All the polymers synthesized had good solubilities in polar solvents and excellent thermal properties. Wide‐angle X‐ray diffraction studies showed that all polyimides were amorphous. Polyimide ultrafiltration asymmetric membranes were successfully prepared by the traditional phase‐inversion method. The cross sections of the polyimide ultrafiltration membranes showed a very thin surface layer and a porous sublayer. The pure water flux was very high and the solute rejection rate at poly(ethylene glycol) of MW 20,000 was above 90%. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1–9, 2000     

封端异氰酸酯合成聚酰亚胺及其性能

以苯甲醇封端的甲苯二异氰酸酯、苯甲醇封端的二苯甲烷二异氰酸酯和3,3',4,4'-二苯酮四酸二酐为原料制备聚酰亚胺,并在高温条件下进一步热处理提高其相对分子质量。采用傅里叶变换红外光谱、热重分析、差示扫描量热法等研究了其结构和性能。结果表明:在250℃处理5 h,然后350℃处理2 h后,成功制备了具有较好热性能和较高相对分子质量且具有良好溶解性能的聚酰亚胺。     

Synthesis and characterization of formal-group-containing diisocyanates and polyimides therefrom

Four new formal-group-containing diisocyanates, namely, bis(3-isocyanatophenoxy) methane, bis(4-isocyanatophenoxy)methane, bis[2-(3-isocyanatophenoxy)ethyl] formal, and bis[2-(4-isocyanatophenoxy)ethyl] formal, were synthesized by the Curtius rearrangement from the corresponding dicarboxylic acids. The diisocyanates were polycondensed with pyromellitic dianhydride (PMDA) and benzophenonetetracarboxylic dianhydride (BTDA) in dimethylacetamide (DMAc) to obtain formal-group-containing polyimides. These polyimides were characterized by viscosity measurements, IR spectroscopy, X-ray diffraction, and thermogravimetric analysis.     

Preparation and properties of soluble and colorless fluorine-containing photoreactive polyimide precursors

Photoreactive polyimide precursors, which are readily soluble in common organic solvents and optically transparent at light of 365 nm wavelength (i-line), similar to aliphatic polyimide precursors, were obtained by polycondensation of biphenyltetracarboxylic dianhydride (BPDA) and fluorine-containing diamine compounds. In particular, the polyimide precursor prepared from 2,2 bis(3-amino-4-methylphenyl) hexatluoropropane showed high solubility in common organic solvents and complete transparence at i-line wavelength. A 3 μm thick film of the polyimide precursor on a silicon wafer was exposed and developed, and offered high resolution (0.5μm line) patterns with an aspect ratio of 6.0. This polymide precursor swells very little in the developing solvent, resulting in the high resolution. Conversion of polyamic acid to polyimide at several curing temperatures was observed by infrared spectrophotometer and thermogravimetry.