Soluble polyimides with trifluoromethyl pendent groups

Unsymmetrical and symmetrical diamine monomers containing trifluoromethyl groups, 2-trifluoromethyl-4,4′-diaminodiphenyl sulfide and 2,2′-bis(trifluoromethyl)-4,4′-diamino-diphenyl sulfide, were synthesized from 2-chloro-5-nitrobenzotrifluoride as a starting material in two steps, respectively. Diamine monomers were polymerized with PMDA, BPDA, BTDA, and ODPA using a solution imidization method with N-methyl-2-pyrrolidone as a solvent at 190 °C to obtain the corresponding polyimides. They had inherent viscosities that ranged from 0.54 to 0.71 dL/g in N-methyl-2-pyrrolidone at 30 °C. All of the synthesized polyimides showed good solubility in polar aprotic solvents and phenolic solvents regardless of the number of trifluoromethyl groups. The 5% weight loss temperatures of the polyimides are in the range of 534–561 °C in nitrogen, and 505–542 °C in air. The T_g values and the thermal expansion coefficients of these polymers are in the range of 234–325 °C and in the range of 47.4–63.2 ppm/°C, respectively. Also, all of the synthesized polyimides have relatively low refractive indices (around 1.6) and birefringence (below 0.36).     

基于酚酞结构共聚型高可溶性聚酰亚胺的合成与性能

以邻甲酚酞与2-氯-5-硝基三氟甲苯为起始原料,通过两步有机反应——芳香亲核取代和氧化还原反应得到芳香二胺单体——4,4"-(2,2’三氟甲基)-二氨基苯氧基-3,3"-二甲基酚酞。利用共聚改性的思路,由两种二胺单体〔4,4"-(2,2"三氟甲基)-二氨基苯氧基-3,3"-二甲基酚酞和2,6-二氨基甲苯〕与一种二酐单体3,3",4,4"-二苯醚四甲酸二酐（ODPA）通过不同投料比以一步法高温缩聚制备得到同时含酚酞、三氟甲基和烷基结构系列共聚型聚酰亚胺。该系列共聚型聚酰亚胺具有优异的溶解性,在室温下不仅可溶于常见的高沸点溶剂：N-甲基吡咯烷酮（NMP）,N,N-二甲基乙酰胺（DMAc）、N,N-二甲基甲酰胺（DMF）和二甲基亚砜（DMSO）,在低沸点溶剂氯仿（CHCl3）、二氯甲烷（CH2Cl2）和四氢呋喃（THF）中也表现出优异的溶解性,可便利地通过其溶液浇筑制备得到系列高性能聚酰亚胺膜材料。该类膜材料玻璃化转变温度在275~314 ℃,其在N2和O2氛围中热失重10%时的温度分别为477~507 ℃和477~49 0 ℃。该类膜材料具有低的介电常数和良好的力学性能：其在1 MHz下介电常数在2.69~2.92之间,拉伸强度、弹性模量和断裂伸长率分别在80~92 MPa、1.2~1.8 GPa和9.2 %~13.5%之间。     

Novel rapid switching and bleaching electrochromic polyimides containing triarylamine with 2-phenyl-2-isopropyl groups

A series of novel organosoluble polyimides and copolyimides with a propeller-shaped triarylamine unit were prepared from diamine and various aromatic dianhydrides via direct polycondensation. All of the polymers possessed tough, flexible, and strong films with high molecular weights. The polyimide and copolyimide films revealed electrochromic characteristics, with a color change from pale yellowish at its neutral state, to green, and finally to blue at its oxidized state, at applied potentials ranging from 0 to 1.50 V. The polyimide (Ib) film exhibited switching times of 4.5 s at 1.08 V at 424 and 877 nm and 1.9 s for fast bleaching due to a pendent substituted 2-phenyl-2-isopropyl group. Cyclic voltammetry (CV) of the polymer films showed two reversible redox couples at potentials of 0.91-0.99 V and 1.30-1.38 V, respectively. The CV results of the model compound M1 and model polyimide M2, were not a match to the oxidation peaks of polyimide Ib, indicating that the contribution of the oxidation was not only from the electron removal of nitrogen atoms.     

含苯并噁唑侧基可溶性聚酰亚胺的合成与性能

合成出了一种含苯并噁唑侧基可溶性的聚酰亚胺(PIBO),并和相应的不含侧基的聚酰亚胺(PIMA)做了对比:实验数据表明,PIBO在保持PIMA良好溶解性的同时,其热稳定性得到了提高,玻璃化转变温度(Tg)由219℃提高到了260℃.     

Synthesis and characterization of novel polyimides derived from 2,6-bis[4-(3,4-dicarboxyphenoxy)benzoyl]pyridine dianhydride and aromatic diamines

A novel pyridine-containing aromatic dianhydride monomer, 2,6-bis[4-(3,4-dicarboxyphenoxy)benzoyl]pyridine dianhydride, was synthesized from the nitro displacement of 4-nitrophthalonitrile by the phenoxide ion of 2,6-bis(4-hydroxybenzoyl)pyridine, followed by acidic hydrolysis of the intermediate tetranitrile and cyclodehydration of the resulting tetraacid. A series of new polyimides holding pyridine moieties in main chain were prepared from the resulting dianhydride monomer with various aromatic diamines via a conventional two-stage process, i.e. ring-opening polycondensation forming the poly(amic acid)s and further thermal or chemical imidization forming polyimides. The inherent viscosities of the resulting polyimides were in the range of 0.51-0.68 dL/g, and most of them were soluble in aprotic amide solvents and cresols, such as N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and m-cresol, etc. Meanwhile, some strong and flexible polyimide films were obtained, which have good thermal stability with the glass transition temperatures of 221-278 °C, the temperature at 5% weight loss of 512-540 °C, and the residue at 800 °C of 60.4-65.3% in nitrogen, as well as have outstanding mechanical properties with the tensile strengths of 72.8-104.4 MPa and elongations at breakage of 9.1-11.7%. The polyimides also were found to possess low dielectric constants.     

Synthesis and characterization of novel fluorinated polyimides derived from 4,4′-[2,2,2-trifluoro-1-(3,5-ditrifluoromethylphenyl)ethylidene]diphthalic anhydride and aromatic diamines

A novel fluorinated aromatic dianhydride, 4,4′-[2,2,2-trifluoro-1-(3,5-ditrifluoromethylphenyl) ethylidene] diphthalic anhydride (9FDA), was synthesized, which was employed to polycondense with various aromatic diamines, including 4,4′-oxydianiline, 1,4-bis(4-aminophenoxy) benzene, 3,4′-oxydianiline and 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene to produce a series of fluorinated aromatic polyimides. The fluorinated polyimides obtained had inherent viscosities ranged of 0.61-1.14 dL/g and were easily dissolved both in polar aprotic solvents and in low boiling point common solvents. High quality polyimide films could be prepared by casting the polyimide solution on glass plate followed by thermal baking to remove the organic solvents and volatile completely. Experimental results indicated that the fluorinated polyimides exhibited good thermal stability with glass transition temperature ranged of 245-283 °C and temperature at 5% weight loss of 536-546 °C. Moreover, the polyimide films showed outstanding mechanical properties with the tensile strengths of 87.7-102.7 MPa and elongation at breaks of 5.0-7.8%, good dielectric properties with low dielectric constants of 2.71-2.97 and low dissipation factor in the range of 0.0013-0.0028.     

Synthesis and characterization of novel polyimides derived from 2-amino-5-[4-(4′-aminophenoxy)phenyl]-thiazole with some of dianhydride monomers

A new kind of aromatic unsymmetrical diamine monomer containing thiazole ring, 2-amino-5-[4-(4′-aminophenoxy)phenyl]-thiazole (APPT), was synthesized. A series of novel polyimides were prepared by polycondensation of APPT with various aromatic dianhydrides via one-step process. The resulting polyimides held inherent viscosities of 0.40-0.71 dL/g and were easily dissolved in strong dipolar solvents. Meanwhile, strong and flexible polyimide films were obtained, which had thermal stability with the glass transition temperatures (T_g) of 268.2-328.8 °C in nitrogen, the temperature at 5% weight loss of 452-507 °C in nitrogen and 422-458 °C in air, and the residue at 800 °C of 54.18-63.33% in nitrogen, as well as exhibited outstanding mechanical properties with the tensile strengths of 105.4-125.3 MPa, elongations at breakage of 6-13%. These films also held dielectric constants of 3.01-3.18 (10 MHz) and showed predominantly amorphous revealed by wide-angle X-ray diffraction measurements.     

Preparation and characterization of organosoluble polyimides based on 1,1-bis[4-(3,4-aminophenoxy)phenyl]cyclohexane and commercial aromatic dianhydrides

A bis(ether amine) III-A containing a cyclohexane cardo group, 1,1-bis[4-(4-aminophenoxy)phenyl]cyclohexane, was synthesized and used as a monomer to prepare polyimides VI-A with six commercial dianhydrides via three different procedures. The intermediate poly(amic acid)s had inherent viscosities of 0.83–1.69 dL g⁻¹ and were thermally or chemically converted into polyimides. Polyimides were also prepared by high-temperature direct polymerization in m-cresol and had inherent viscosities higher than the thermally or chemically cyclodehydrated ones. To improve the solubility of polyimides, six copolyimides were also synthesized from bis(ether amine) III-A with a pair of dianhydrides, which contained 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride or 4,4′-hexafluoroisopropylidenediphthalic anhydride. Series VI-A polyimides were characterized by the good physical properties of their film-forming ability, thermal stability, and tensile properties. A comparative study of the properties, with the corresponding polyimides derived from 2,2-bis[4-(4-aminophenoxy)phenyl]propane, is also presented. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2750–2759, 2001     

Functional hydrogels with a multicatalytic activity for bioremediation: Single‐step preparation and characterization

In a single‐step free radical reaction, multicatalytic hydrogels were synthesized by covalent immobilization of Pancreatin onto a film composed of Acrylamide and Polyethylene glycol dimethacrylate750. Hydrogels were characterized by determination of their dynamic swelling ratios and each catalytic activity was extensively investigated by determination of kinetic parameters K_M and V_max. The immobilization process was found to preserve the hydrolytic properties of Pancreatin (Protease, Lipase, and Amylase catalytic activities). Catalytic efficiencies were the highest with Protease and the lowest with Amylase. Reusability values higher than 60% after 10 repeated cycles proved the applicability of the proposed material in industrial practice. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43338.     

In situ FTIR spectroelectrochemistry of poly[2-(3-thienyl)ethyl acetate] and its hydrolyzed derivatives

Poly[2-(3-thienyl)ethyl acetate] (PTEtAc) was chemically synthesized and transformed to partially hydrolyzed PTEtAc (PTEtAcOH) and poly[2-(3-thienyl)ethanol] (PTEtOH). The influence of the acetoxy and hydroxyl terminal functionalities in the side groups on the electrochemical properties of these polyalkylthiophenes was studied by cyclic voltammetry and in situ FTIR spectroelectrochemistry. The cyclic voltammograms point to a chemically reversible behaviour of the p-doping process for PTEtAc and PTEtAcOH, while for PTEtOH the redox activity of the polymer film is lost during consecutive potential scans.The attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was used to investigate the p-doping of the three different type of thiophene polymer films. In situ FTIR spectra taken at different electrode potentials in a cyclovoltammetric scan display the doping induced changes of the polymer pattern. Important differences in the behaviour of the polymers were observed and interpreted in terms of different film structures.     

On the presence of polytetrahydrofuran in the polyspiro‐phosphazenes [NP(O2C12H8)]n prepared from [NPCl2]n and 2,2′‐dihydroxybiphenyl in THF as solvent

Polydichlorophosphazene [NPCl₂]_n reacts with the diphenol 2,2′‐(HO)C₆H₄‐C₆H₄(OH) in THF in the presence of K₂CO₃ to give the polymers [NP(O₂C₁₂H₈) · x(OC₄H₈)]_n (1) that contain variable ammouts of polytetrahydrofuran (PTHF) with x ranging from 0.05 to 0.8. This PTHF content (x) depends on the method followed to prepare the THF solutions of [NPCl₂]_n used for the reactions with the biphenol and can be made negligibly small, forming these solutions in the presence of K₂CO₃. This reveals the presence in the [NPCl₂]_n of acidic species capable of catalyzing the ring opening polymerization of THF. Polyphosphazene [NP(O₂C₁₂H₈)]_n (2) was prepared completely free of PTHF using dioxane as solvent. A comparison of the thermal behavior and morphological data of the polymers 1, 2, PTHF (5), and mixtures of [NP(O₂C₁₂H₈)]_n + x(OC₄H₈)_m (4) revealed that the products 1 are strongly interacting polymer blends and ruled out the possibility of block copolymers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 568–576, 2000     

Donor copolymer with benzo[1,2‐b:4,5‐b′]dithiophene and quinoxaline derivative segments for photovoltaic applications

A donor copolymer Poly{2,6‐4,8‐bis(2‐ethylhexyl)benzo[1,2‐b:3,4‐b′]dithiophene‐5,8‐2,3‐bis(5‐octylthiophen‐2‐yl)quinoxaline} (PBDTThQx) with benzo[1,2‐b:4,5‐b′]dithiophene and quinoxaline derivatives was synthesized and characterized with NMR, ultraviolet–visible spectroscopy, thermogravimetric analyses, and cyclic voltammetry. Photovoltaic devices with the configuration indium tin oxide–poly(3,4‐ethylenedioxythiophene)–poly(styrene sulfonate)–PBDTThQx–[6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PC₆₁BM)–LiF–Al were fabricated, in which PBDTThQx performed as the electron donor and PC₆₁BM was the electron acceptor in the active layer. The device presented reasonable photovoltaic properties when the weight ratio of PBDTThQx:PC₆₁BM reached 1:3. The open‐circuit voltage, fill factor, and power conversion efficiency were gauged to be 0.75 V, 0.59, and 0.74%, respectively. The experimental data implied that PBDTThQx would be a promising donor candidate in the application of polymer solar cells. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40279.     

Dynamic supramolecular polymers built from cucurbit[n]urils and viologens

This review article focuses on supramolecular assemblies involving cucurbit[n]uril‐based containers and viologen guests as key building elements. Cucurbit[n]urils (CB[n], n = 5–8,10) are fascinating hosts forming a wide range of inclusion complexes (caviplexes) with 4,4′‐bipyridinium salts, known as viologens, either as discrete 1:1 inclusion compounds with CB[7] or as ternary inclusion compounds involving two hosts or two guests (2:1 with CB[7] and 1:2 or 1:1:1 with CB[8]). This property is currently being actively exploited to design and prepare self‐assembled dynamic stimuli‐responsive supramolecular polymers including gels, vesicles, films and organized arrays of polymeric microspheres or nanoparticles. This review highlights the main benefits of such polymers and gives an overview of the achievements and progress made in this field over the past decades. © 2018 Society of Chemical Industry     

Preparation and properties of polyimides based on bis[3,5‐dimethyl‐4‐(4‐aminophenoxy)phenyl]methane

A series of polyimide (PI) thin films were synthesized based on bis[3,5‐dimethyl‐4‐(4‐aminophenoxy)phenyl]methane and conventional aromatic dianhydrides. The structures and properties of the thin films were measured with Fourier transform infrared, NMR, thermogravimetric analysis, dynamic mechanical analysis, and impedance analysis. The PI films exhibited glass‐transition temperatures in the range of 211–300°C and possessed initial thermal decomposition temperature reaching up to 457–482°C in air and 461–473°C in nitrogen. Some PI films had high solubility in organic solvents such as 1‐methyl‐2‐pyrrolidinone, N,N‐dimethylformamide, N,N‐dimethylacetamide, dimethyl sulfoxide, m‐cresol, tetrahydrofuran, and CHCl₃. The mechanical properties of these films were also examined. The dielectric constants of the films were in the range of 2.8–3.3 at 25°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1265–1270, 2007     

Electropolymerization under potentiodynamic and potentiostatic conditions: Spectroelectrochemical study on electrosynthesis of poly[4,4′-bis(2-methylbutylthio)-2,2′-bithiophene]

In order to perform an in-depth study on the electropolymerization mechanism of bis(alkyl)-substituted bithiophenes, poly[4,4′-bis(metylbutylthio)-2,2′-bithiophene] (poly-MBTBT) has been electrogenerated by using both potentiodynamic and potentiostatic techniques under different experimental conditions. Bidimensional spectroelectrochemical data have allowed us to obtain valuable information about both the polymer and the soluble oligomers electrogenerated in the process. The same kind of oligomers has been observed in the potentiodynamic and potentiostatic polymerization.     

Preparation and characterization of polyaniline–1‐hydroxyethane 1,1‐diphosphonic acid salt and its application as a catalyst for the synthesis of N‐benzylidine‐2‐phenyl imidazo[1,2‐a]pyridines

A novel, efficient, and easily synthesizable catalyst, an emeraldine form of polyaniline (PANI)?1‐hydroxyethane 1,1‐diphosphonic acid salt (HEDP), was successfully synthesized and demonstrated as a reusable polymer‐based solid acid catalyst in the synthesis of N‐benzylidine‐2‐phenyl imidazo[1,2‐a]pyridines with 2‐aminopyridine with aromatic aldehydes and trimethyl silylcyanide at room temperature. PANI–HEDP was characterized by Fourier transform infrared spectroscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, field emission scanning electron microscopy, and conductivity measurements. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2995–3000, 2013     

Geometrical structures of poly(haloalkyl propiolate)s prepared with a [Rh(norbornadiene)Cl]2 catalyst

The polymerization of ω-haloalkyl propiolates initiated by [Rh(norbornadiene)Cl]₂ in methanol has been investigated in detail together with the geometrical forms of the resulting polymers. The polymer yield and molecular weight of poly(2-haloethyl propiolate)s (P(2XEPA)s) were markedly reduced in the order of X = Cl, Br, and I. ¹H NMR, electron spin resonance, and diffuse reflective UV-vis spectroscopic studies of P(2XEPA)s revealed that the content of cis form regarding the CC was markedly decreased from 60% for P(2ClEPA) to 15% for P(2IEPA). The decrease in the cis content also resulted in notable reduction of the crystallinity of the polymer from 30% for P(2ClEPA) to less than 10% for P(2IEPA). Compression of P(2XEPA)s at room temperature induced the so-called cis-to-trans isomerization accompanied with decomposition of the polymers.     

Effects of plasticization conditions on the structures and properties of cellulose packaging films from ionic liquid [BMIM]Cl

By using natural softwood pulp with higher degree of polymerization (DP = 1460) as cellulose source, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid as solvent and glycerol as plasticizer, a novel cellulose packaging film was prepared. The effects of plasticization conditions on the structures, mechanical properties, permeability for oxygen and water vapor were measured by Wide-angle X-ray scattering, thermogravimetric analysis, scanning electron microscopy (SEM), and other techniques. The investigations suggested that the glycerol concentration and plasticizing time had great effect on the properties of the regenerated cellulose films. The crystal transformation of cellulose I to cellulose II occurred during the dissolution and regeneration process, combining with the decrease of thermal stability. The tensile strength decreased rapidly with the addition of glycerol and prolongation of plasticizing time. However, elongation at break of the regenerated cellulose films increased at first and then decreased with increasing of glycerol concentration and plasticizing time. The morphologies for the fracture surface obtained from SEM images showed transformation of typical brittle fracture to plastic deformation with increasing of glycerol concentrations. It was also found that both water vapor permeability and oxygen permeability of the regenerated cellulose films decreased slowly with increasing of glycerol concentrations and plasticizing time, but water vapor permeability and oxygen permeability presented an almost opposite trend. The films prepared by using ionic liquid technology would be used in food packaging or other fields as a kind of green packaging material. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Novel 1,4‐diketo‐3,6‐diphenyl pyrrolo[3,4‐c]pyrrole (DPP)‐based copolymers with large Stokes shift

Two novel alternating π‐conjugated copolymers, named PDPPDOPV and PDPPDOPE, constituted of 1,4‐diketo‐3,6‐diphenyl pyrrolo[3,4‐c]pyrrole (DPP) with 2,5‐dioctyloxy‐1,4‐phenylenevinylene (DOPV) or 2,5‐dioctyloxy‐1,4‐phenyleneethynylene (DOPE), respectively, were synthesized and characterized by UV‐vis, FT‐IR, and photoluminescence spectroscopy. They are dark red solid readily soluble in various common organic solvents including THF and chloroform. The UV‐vis absorption spectra of the polymers show strong absorption bands, which correspond to the π‐π* transition of π‐conjugated segments. Photoluminescence (PL) spectra show that both polymer films and solution have large Stokes shifts. From their fluorescence behavior, Stokes shifts of 173 nm and 199 nm are derived for the films of PDPPDOPV and PDPPDOPE, respectively, which are the largest two values ever reported for DPP‐containing polymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and properties of core [poly(styrene‐n‐butyl acrylate)]–shell [poly(styrene–methyl methacrylate–vinyl triethoxide silane)] structured latex particles with self‐crosslinking characteristics

Structured latex particles with a slightly crosslinked poly(styrene‐n‐butyl acrylate) (PSB) core and a poly(styrene–methacrylate–vinyl triethoxide silane) (PSMV) shell were prepared by seed emulsion polymerization, and the latex particle structures were investigated with Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetry, transmission electron microscopy, and dynamic light scattering. The films that were formed from the structured core (PSB)–shell (PSMV) particles under ambient conditions had good water repellency and good tensile strength in comparison with films from structured core (PSB)–shell [poly(styrene–methyl methyacrylate)] latex particles; this was attributed to the self‐crosslinking of CH₂?CH? Si(OCH₂CH₃)₃ in the outer shell structure. The relationship between the particle structure and the film properties was also investigated in this work. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1824–1830, 2006