Aromatic polyimides from m‐phenylene diamines containing pendant groups: Synthesis and characterization

Two diamine monomers, 4‐[4‐(1‐methyl‐1‐phenylethyl)phenoxy]‐1,3‐diamino benzene and 4‐{4‐[(4‐methylphenyl)sulfonyl]phenoxy}‐1,3‐diamino benzene, were synthesized, and both diamines were polycondensed with three commercial dianhydrides to obtain aromatic polyimides containing pendant groups. The polyimides were characterized by solubility tests, viscosity measurements, IR, ¹H‐NMR, and ¹³C‐NMR spectroscopy, X‐ray diffraction studies, and thermogravimetric analysis. The polyimides had inherent viscosities of 0.33–0.58 dL/g in m‐cresol at 30 ± 0.1°C. All the polyimides were amorphous and were soluble in solvents such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, N,N‐dimethylformamide, and m‐cresol. Thermogravimetric analysis of the polyimides indicated no weight loss below 410°C under a nitrogen atmosphere. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1377–1384, 2005     

Synthesis and characterization of highly optical transparent and low dielectric constant fluorinated polyimides

Multitrifluoromethyl-substituted aromatic diamines, 1,1-bis[4-(4′- amino-2′-trifluoromethylphenoxy)phenyl]-1-(3″-trifluoromethylphenyl)-2,2,2-trifluoroethane (12FDA) and 1,1-bis[4-(4′-amino-2′-trifluoromethylphenoxy)phenyl]-1-[3″,5″-bis (trifluoromethyl)phenyl]-2,2,2-trifluoroethane (15FDA) were synthesized, which were employed to react with various aromatic dianhydrides to yield a series of highly fluorinated polyimides. The fluorinated polyimides synthesized showed great solubility with inherent viscosities of 0.47-0.69 dL/g. The strong and tough polyimide films exhibited good thermal stability with the glass transition temperature (T_g) of 209-239 °C and outstanding mechanical properties with the tensile strengths of 88-111 MPa and tensile modulus of 2.65-3.17 GPa. Dielectric constants of as low as 2.49 and low moisture absorptions (0.17-0.66%) were measured. The fluorinated polyimide films (7-10 μm in thickness) also showed highly optical transparency with light transmittance at 450 nm of as high as 97.0% and cutoff wavelength of as low as 298 nm. The average refractive indices and birefringence of the fluorinated polyimide films were measured in the range of 1.5060-1.5622 and 0.0036-0.0095, respectively. PI-7 and PI-8 exhibited low light-absorption in the near-infrared region, especially at the optocommunication wavelength of 1310 nm and 1550 nm.     

Synthesis and properties of ultralow dielectric constant porous polyimide films containing trifluoromethyl groups

In this research, a series of porous copolyimide (co‐PI) films containing trifluoromethyl group (CF₃) were facilely prepared via a phase separation process. The co‐PI were synthesized by the reaction of benzophenone‐3,3′,4,4′‐tetracarboxylic dianhydride (BTDA) with two diamines of 4,4′‐diaminodiphenyl ether (ODA) and 3‐trifluoromethyl‐4,4'‐diaminodiphenyl ether (FODA) with various molar ratios. The flexible and tough porous co‐PI films with about 300 μm thickness and 8～10 μm average diameter could be obtained by solution casting conveniently. The thermal properties of the obtained porous co‐PI films were excellent with a glass transition temperature at 270 °C ～ 280 °C and only 5% weight loss in temperature from 530 °C to 560 °C under nitrogen atmosphere. In addition, the dielectric and hydrophobic properties of porous co‐PI films were remarkably improved owing to the presence of trifluoromethyl groups (CF₃) in the polymer chains. Moreover, our synthesized porous co‐PI films also showed good mechanical properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44494.     

Telechelic siloxanes with hydrogen‐bonded polymerizable end‐groups. II. IR studies of end‐groups interactions—Model amides and ureas

Hydrogen‐bonding phenomena in amides and ureas are of great practical and theoretical importance. In this article, we report on infrared temperature studies aimed at the elucidation of the hydrogen‐bonding phenomena of (meth)acrylamide groups directly linked to the alkyl groups of telechelic polydimethylsiloxane (PDMS) which serve as models of monoamides, or linked to the alkyl groups of telechelic PDMS through amide spacers‐models of diamides (dipeptides). Similarly, we have examined the hydrogen‐bonding phenomena in urea‐terminated telechelic PDMSs to which free‐radically polymerizable groups (methacrylate, α‐methylstyryl) are attached. Hydrogen bonding in the derivatives of these substituted silicone amides and ureas in the unreacted (liquid) state has been studied, as well as in films formed via ultraviolet‐initiated free‐radical polymerization of those reactive end‐groups. The extreme flexibility of the silicones provides a medium in which polar, hydrogen‐bonding end‐groups (amides, diamides, and ureas) phase‐separate to form their own domains wherein they can freely aggregate in an essentially unperturbed state, when in the liquid form. When the vinyl end‐groups are polymerized, interactions between the hydrogen bonding groups attached to them can be studied in a spatially constrained environment. High thermal stability of the silicones allows the study of the hydrogen bonding (H‐bonding) phenomena of these models within a broad temperature range. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and properties of polyimide nanocomposites via a soluble polyisoimide precursor

A polyisoimide based on 4,4′‐oxydiphthalic dianhydride and 4,4′‐oxydianiline was synthesized and used for the preparation of nanocomposites with commercial organoclays by the solution dispersion technique. The cast composite films were heat‐treated to convert them into polyimide nanohybrid films. Homogeneous dispersions were obtained at lower clay concentrations (<5 wt %), and this was confirmed by X‐ray diffraction and transmission electron microscopy. The nanocomposites displayed improved thermal and mechanical properties. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 869–874, 2006     

Synthesis,characterization, and thermal curing of a novel polyhedral oligomeric octa(propargylaminophenyl)silsesquioxane

A novel polyhedral oligomeric octa(propargylaminophenyl)silsesquioxane (OPAPS, (SiO_1.5C₆H₄NHCH₂C?CH)₈) was prepared from octa(aminophenyl)silsesquioxane and propargyl bromide. The chemical structure of OPAPS was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance, X‐ray diffraction (XRD), high‐performance liquid chromatography, gel permeation chromatography, differential scanning calorimetry, and thermal gravimetric analysis (TGA). The structure of the thermally cured polymer of OPAPS was characterized by FTIR, XRD, and TGA. It had good thermal stability. TGA demonstrated that the thermal decomposition temperatures (T_d5) of the cured OPAPS polymer in nitrogen and air were 455.6 and 458.8°C, respectively. The thermal curing reaction kinetics of OPAPS were studied and some kinetic parameters were obtained. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Polyimides possessing bulky phosphorus groups: Synthesis and characterization

A series of polyimides with bulky pendent groups containing phosphorus were obtained from polymerization of various dianhydrides with a new diamine (2DOPO‐A) bearing two bulky (9,10‐dihydro‐9‐oxa‐10‐oxide‐10‐phosphaphenanthrene‐10‐yl) (DOPO) substituents. The resulting polymers had inherent viscosities of 0.15–0.32 dL/g and glass transition temperatures of 260–283°C. The polyimides were soluble in some organic solvents due to the incorporation of bulky and polar DOPO groups. The non‐coplanar cardo structure of 2DOPO‐A also contributed to the improvement in the solubility of the polyimides. Incorporating DOPO groups into polyimides resulted in polymers with low initial decomposition temperatures (IDT; 310–362°C) due to the independent decomposition of the DOPO groups. Thermogravimetric analysis showed that the DOPO‐containing polyimides exhibited high integral procedural decomposed temperatures (IPDT) of 891–950°C. Incorporation of DOPO group into polyimides also improved their weight loss rate, thermal stability, thermal‐oxidative stability, and heat insulating property in the high temperature region. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 791–796, 2003     

Synthesis and characterization of a novel fibrous antibacterial fiber with organophorsphor functional groups

A novel antibacterial fiber named ethyltriphenylphosphonium bromide‐polyacrylonitrile fiber (ETPB‐PANF) was synthesized by chemical modification of PANF reacted with ETPB. The PANF was first immersed in NaOH solution to get Na‐PANF with ? COONa groups. Na‐PANF was then reacted with ETPB to get the final fiber. During the process of synthesis, this article investigated on the initial concentration of ETPB, the contact time, the reaction temperature, and the pH of the solution that may have effect on the properties of ETPB‐PANF. ETPB‐PANF was characterized by Fourier transform infrared spectroscopy, thermo gravimetric analyzer, scanning electron microscope, and X‐ray photoelectron spectroscopy, and the releasing amount of ETPB from ETPB‐PANF was examined by inductively coupled plasma atomic emission spectrometry. The antibacterial activity of ETPB‐PANF was examined against Escherichia coli and Staphylococci aureus by improved shake flask method in sterile saline. The results showed that organophorsphor functional groups have been successfully grafted on PANF, and ETPB‐PANF showed good antibacterial abilities for E. coli and S. aureus. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40935.     

Synthesis of chloromethylstyrene‐tetraethyleneglycol dimethacrylate copolymer beads having various phenolic derivatives immobilized via amide bond and their antioxidation activity

Resins having phenolic derivatives were prepared by treating a resin (RAS‐4G), having benzylamino groups, with benzoic acids containing phenolic hydroxyl groups. The RAS‐4G was prepared by treating macroreticular chloromethylstyrene‐tetraethyleneglycol dimethacrylate (4G) copolymer beads with potassium phthalimide in N,N‐dimethylformamide, followed by reflux in an ethanol/hydrazine monohydrate mixture. 4‐Hydroxy benzoic acid, (2,4‐, 3,4‐, and 3,5‐)dihydroxy benzoic acids, 3,4,5‐trihydroxy benzoic acid, etc., were used as benzoic acids with phenolic hydroxyl groups. The antioxidation ability of the resins having phenolic derivatives was investigated against the generation of 1,4‐dioxane hydroperoxide. The resins showed high inhibition ability against the generation of hydroperoxide. In particular, the resin (RAS‐4G‐3,4‐DHBA) having two phenolic hydroxyl groups had the highest inhibition ability. The resins were found to act as radical scavengers during the generation of 1,4‐dioxane hydroperoxide by UV irradiation in the presence of oxygen. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2097–2104, 2005     

Imidazole functionalized polyaniline: Synthesis,characterization, and Cu (II) coordination studies

Polyaniline functionalized with imidazole as strategically designed receptor group in its backbone was synthesized for copper binding. The synthesized polymer has been characterized using FTIR, NMR, and UV‐Vis spectroscopic techniques. The addition of copper (II) to the polymer distinctly changes the properties such as crystallinity, molecular weight, aggregation, and electronic properties. XRD, DLS, SEM, and four‐point probe techniques have been used for study of these changes. It is observed that the secondary ion generated as a result of copper coordination results in the doping of the polyaniline backbone, which enhances the conductivity by one order of magnitude. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Novel trifluoromethyl‐containing poly(amide–imide)s: Organosolubility,optical behavior,thermostability, and crystallinity

A new dicarboxylic acid monomer, 2,6‐bis(1,3‐dioxo‐5‐carboxyisoindolin‐2‐yl)‐4,4′‐bis(trifluoromethyl)‐1,1′‐diphenyl ether (IFDPE), bearing two preformed imide rings was synthesized via a three‐step manner from 4‐(trifluoromethyl)phenol and 4‐chloro‐3,5‐dinitrobenzotrifluoride. The monomer IFDPE was then used to prepare a series of novel trifluoromethyl‐containing poly(amide–imide)s via a direct phosphorylation polycondensation with various aromatic diamines. The intrinsic viscosities of the polymers were found to be in the range 0.86–1.02 d/g. The weight‐ and number‐average molecular weights of the resulting polymers were determined with gel permeation chromatography. The polymeric samples were readily soluble in a variety of organic solvents and formed low‐color, flexible thin films via solution casting. The values of the absorption edge wavelength were determined by ultraviolet–visible spectroscopy, and all of the resulting poly (amide–imide)s films exhibited high optical transparency. The resulting polymers showed moderately high glass‐transition temperatures in the range 295–324°C and had 10% weight loss temperatures in excess of 524°C in nitrogen. The crystallinity extents were qualitatively investigated with wide‐angle X‐ray diffraction measurements. Scanning electron microscopy images revealed an agglomerated bulk with nonuniformity on the surface. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis,cure and pyrolysis behavior of heat‐resistant boron‐silicon hybrid polymer containing acetylene

The synthesis and characterization of a novel heat‐resistant boron‐silicon hybrid polymer containing acetylene (PBSA) and its conversion to a highly crosslinked thermoset were discussed. The polymer was synthesized from phenylboron dichloride using Grignard reagent method. The structure of PBSA was characterized by using Fourier transform infrared spectra, ¹H‐NMR, ¹³C‐NMR, and gel permeation chromatography. PBSA was thermosetting, highly heat‐resistant, high‐viscous, orange liquid at room temperature and good solubility in common organic solvents. Differential scanning calorimetry and thermogravimetric analysis analyses showed that the PBSA had excellent thermal and oxidative stability and the temperature of 5% weight loss (Td₅) were 650 and 638°C under nitrogen and air, respectively, and the residue at 1000°C were 93.3 and 91.3%, respectively, which indicated that the incorporation of boron and silicon into polymeric backbone was found to improve thermal and oxidative properties. X‐ray diffraction and scanning electron microscope were also used to analyze the formation of pyrolytic products. The results showed that the pyrolysis of PBSA resin was made up of β‐SiC and graphite. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

An imidazolium‐functionalized isobutylene polymer having improved mechanical and barrier properties: Synthesis and characterization

Brominated poly(isobutylene‐co‐p‐methylstyrene) (BIMS) is of great use to industries because of its extremely good permeability properties. However, it lacks strength and adhesion necessary to make it amenable to various processing techniques. To overcome the limitations of BIMS, ionic modification via nucleophilic substitution of bromine by 1‐methylimidazole through a facile synthetic route is presented. The modified ionic product was characterized by various techniques such as solubility, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis, and dynamic mechanical analysis. The FTIR spectrum of the obtained samples showed a distinct peak around 1261 cm^?1 corresponding to C? N stretching vibration and reduction in peak intensity around 695 cm^?1 corresponding to C? Br stretching vibration. NMR also clearly showed the occurrence of a singlet peak corresponding to the methyl protons of imidazole in the region of 4.1 ppm and a shift in the methylene protons adjacent to the benzene ring confirming the substitution of bromine atom by imidazole ring. The reaction at reflux temperature of 130°C for 48 h yielded the highest level (3.1 wt %, 1.18 mol %) of modification while optimizing the reaction parameters. The modified ionic polymers displayed greater thermal stability, greater flexibility, improved tensile strength, and higher barrier properties compared to the unmodified BIMS. A 1.8‐fold increase of elongation at break was achieved with 1.18 mol % (3.1 wt %) of modification. The modified polymers also showed remarkable drop in oxygen transmission rate values from 10^?16 to 10^?18 m³ m/m²/s/Pa, which further highlights their improved properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Facile preparation and characterization of soluble aramid

It remains a problem to prepare cost‐effective aramid with good solubility via a simple method since the commercialization of aromatic polyamides such as Kevlar and Nomex by DuPont in 1960s. Herein, we report the facile preparation and properties of an aromatic polyamide copolymerized by 2,6‐naphthalene dichloride (26N‐COCl), 4,4′‐oxydianiline, and m‐phenylenediamine. The synthetic route is very facile and cost‐effective. The modified aramids possess excellent comprehensive properties. The polymers are soluble in some organics. Their thermal stabilities are excellent, with 5% weight loss temperatures (T_d,5%'s) in air higher than 460 °C and glass transition temperatures (T_g's) higher than 280 °C. These polymers are easily processed into films, fibers, and tubes. The products exhibit high strength. For example, the films have excellent mechanical strength, with a tensile strength up to 139 MPa, a tensile modulus up to 3.45 GPa, and an elongation of 11%. The films are also transparent and fluorescent. The overall properties are better than those of the commercial Nomex. The facilely prepared aramids with good solubility are very promising for commercial use. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46341.     

Synthesis and characterization of a novel highly phosphonated water-insoluble polymer

A novel polymer, functionalized by tetrafluoroaryl phosphonic acid units, was prepared by free-radical polymerization of the corresponding styrene monomer. The obtained polymer was analyzed by gel permeation chromatography, differential scanning calorimetry, and spectroscopy (NMR, IR). Ion exchange capacity of the water-insoluble polymer was determined in methanol solution by titration with 0.1M NaOH. The proton conductivity of the polymer of 9.91 × 10⁻⁷ S cm⁻¹ as disclosed by electrochemical impedance spectroscopy renders this polymer a promising candidate for solid electrolyte applications or as a water-insoluble dopant for proton exchange membrane applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48235.     

Magnetic polymer microspheres with azidocarbonyl groups: Synthesis,characterization and application in protein immobilization

A novel magnetic polymer microsphere with amide groups and carboxyl groups was synthesized and reported here. The azidocarbonyl groups were derived from amide groups and linked to the proteins to investigate their immobilization capacity. The morphology, size, functional groups and magnetic properties of magnetic microspheres were characterized by optical microscopy, particle size analyzer, atom force microscopy, magnetic force microscopy, fourier transform infrared spectrometer, vibrating‐sample magnetometer and thermal gravimetric analysis. The results indicated that the magnetic polymer microspheres had a well spherical shape with the size ranging from 1 to 10 μm, highly reactive functional groups, superparamagnetism and strong magnetic responsibility with saturation magnetization of 18.443 emu/g and Fe₃O₄ content around 21%. The immobilization capacity (η) was over 70%. The novel azidocarbonyl magnetic polymer microspheres showed potentials to be a good magnetic support and promising applications in bioseparation and biomedical fields. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of thermally stable polymers (polybenzimidazoles)

In this study, an alternative synthesis of polybenzimidazoles was performed with aromatic hydroxamoyl chloride. In contrast to the literature, polybenzimidazoles were obtained through the reaction of hydroxamoyl chlorides with 3,3′‐diaminobenzidine or 1,2,4,5‐tetraaminobenzene. The characterization of the polymers was performed with Fourier transform infrared, ¹H‐NMR, elemental analysis, LC mass spectrometry, and differential thermogravimetry/thermogravimetric analysis. Finally, the adhesion, corrosion resistance, and conducting properties of the synthesized polymers were examined. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Thermal degradation of high‐temperature fluorinated polyimide and its carbon fiber composite

High‐temperature polymers are being used for a broad range of applications, such as composite matrices for structural applications (e.g., high speed aircraft). Polyimides are a special class of polymers that meet the thermal and oxidative stability requirements for high temperature composite aerospace applications. A weight loss study was performed on a fluorinated polyimide resin and its carbon fiber composite in an effort to determine its thermal stability and degradation mechanisms. Experiments were conducted using a preheated oven and thermogravimetric analysis to obtain the weight loss. Regardless of the method used, the resin and composite exhibited excellent thermal stability (less than 1% weight loss) below 430°C, regardless of 2–20 min of exposure. After 20 min of exposure at 510°C, the composite remained relatively stable with only 5.3% weight loss using the oven technique, whereas the neat polyimide sustained 12.6%. When degradation occurred, it was found to be the result of thermolysis and oxidation (to a lesser extent). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of crosslinking waterborne fluorinated polyurethane‐acrylate with core‐shell structure

Crosslinking core‐shell emulsions of waterborne fluorinated polyurethane‐acrylate (WFPUA) were successfully synthesized using a solvent‐free method. The crosslinkers of diacetone acrylamide and adipic dihydrazide were introduced into the WFPUA emulsions. The physical properties of hybrid emulsions such as the average particle size, stability, and viscosity were characterized. The core‐shell of crosslinking WFPUA emulsion synthesized in this study was observed by transmission electron microscopy. Then, the results of Fourier transform infrared spectroscopy, atomic force microscopy, and X‐ray photoelectron spectroscopy indicated that the fluorinated monomer (FA) had been polymerized into the crosslinking waterborne polyurethane‐acrylate polymer, and the fluorinated groups have evident enrichment on the film‐air surface with the increase of FA content. At the same time, the thermal properties, water repellent/antifouling properties, and mechanical properties were measured. Moreover, the thermal properties and the elongation are raised but tensile stress and shore hardness are decreased with the increase of FA content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40970.     

Synthesis of macroreticular copolymer beads having various phenolic derivatives immobilized via different bond and their radical scavenging activity

The macroreticular copolymer beads (RCS‐4G) were prepared by suspension copolymerization of chloromethylstyrene (CS) and tetraethyleneglycol dimethacrylate (4G) in water, using cyclohexane as a diluent. Then, the copolymer beads carrying phenolic derivatives immobilized via amide, methylene, or ether bond were prepared by subsequent reactions of RCS‐4G with various phenolic derivatives. The radical scavenging activity against 2,2‐Diphenypicrylhydrazil (DPPH) of the copolymer beads carrying phenolic derivatives immobilized was investigated in toluene. It was found that the copolymer beads had high radical scavenging activity against DPPH. The order of the radical scavenging activity against DPPH of the copolymer beads carrying phenolic derivatives immobilized did not coincide with the order of inhibition activity against the generation of 1,4‐dioxane hydroperoxide. The radical scavenging activity against DPPH of the copolymer beads having phenolic derivatives immobilized via methylene bond or ether bond was higher than that of the copolymer beads having phenolic derivatives immobilized via amide bond. It was found that the radical scavenging activity of the copolymer beads having phenolic derivatives was affected by not only the kind of phenolic derivatives immobilized and bond groups through which phenolic compounds were immobilized, but also the swelling ratio of the copolymer beads in toluene. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4791–4800, 2006