Synthesis and characterization of soluble copolyimides containing chalcone and phosphine oxide moieties in the main chain

The functional diamines 3,3′‐diaminochalcone and bis(3‐aminophenyl)‐3,5‐bis(trifluoromethyl)phenyl phosphine oxide were successfully prepared by simple and convenient procedures with short reaction times, and the overall yields were 78 and 70%, respectively. Copolyimides prepared from 3,3′‐diaminochalcone, bis(3‐aminophenyl)‐3,5‐bis(trifluoromethyl)phenyl phosphine oxide, and 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride exhibited excellent solubility in several organic solvents, such as dimethyl sulfoxide, N,N‐dimethylformamide, N‐methyl pyrrolidone, tetrahydrofuran, and acetone. They also showed very good thermal stability even up to 450°C for 5% weight loss (by thermogravimetric analysis) in nitrogen and a high glass‐transition temperature up to 274°C (by differential scanning calorimetry) in nitrogen. The copolymers' adhesive and photoreactive properties were also investigated, and it was confirmed that the copolyimide containing chalcone and phosphine oxide moieties in the main chain had good adhesiveness and photoreactivity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Adhesion property of novel polyimides containing fluorine and phosphine oxide moieties

Novel diamine monomers containing fluorine and phosphine oxide - bis(3-aminophenyl)-3,5-bis(trifluoromethyl)phenyl phosphine oxide (mDA6FPPO) and bis(3-aminophenyl)-4-(trifluoromethyl)phenyl phosphine oxide (mDAFPPO) - were utilized to prepare polyimides with dianhydrides such as 6FDA, BTDA or ODPA by the conventional two-step route, i.e. preparation of poly(amic acid) followed by solution imidization. The polyimides were characterized by FT-IR, NMR, DSC, and intrinsic viscosity measurements. The adhesion property of the polyimides was evaluated via a peel test with bare Cu foil, as well as silane/Cr-coated Cu foil, and failure surfaces were analyzed by SEM/EDX to elucidate the failure mechanism. The results were compared with those from the polyimides prepared from bis(3-aminophenyl)phenyl phosphine oxide (mDAPPO) containing only the phosphine oxide moiety, 1,1-bis(4-aminophenyl)-1-phenyl-2,2-trifluoroethane (3FDAm) containing only the fluorine moiety, and a commercial 3,3′-diaminodiphenylsulfone (mDDS). The polyimides with 3FDAm exhibited the highest T _g, followed by the mDAPPO-, mDA3FPPO-, and mDA6FPPO-based polyimides, but the mDAPPO-based polyimides exhibited the highest adhesion properties, followed by mDA3FPPO, mDA6FPPO, mDDS, and 3FDAm, which is attributed to the phosphine oxide and fluorine moieties.     

Amine-terminated aromatic and semi-aromatic hyperbranched polyamides: synthesis and characterization

A facile synthetic approach to aromatic and semiaromatic amine-terminated hyperbranched polyamides via direct polymerization of triamine (B₃) with different diacid chlorides (A₂) was explored. An aromatic triamine, 1,3,5-tris(4′-aminophenylcarbamoyl)benzene (TAPCB), was synthesized and monomers were characterized by elemental analysis, FTIR, ¹H and ¹³C NMR spectroscopy. Finally, the polycondensation reaction of TAPCB with terephthaloyl chloride (TPC), isophthaloyl chloride (IPC), sebacoyl chloride (SC) and adipoyl chloride (AC) resulted in the preparation of four hyperbranched polyamides i.e., HBPA 1, 2, 3 and 4, respectively. FTIR and ¹H NMR analyses confirmed the structures of the ensuing polymers and DB was found between 0.51–0.55. These thermally stable amorphous HBPAs were soluble in polar aprotic solvents at room temperature having glass transition temperatures (T_g) between 138–198 °C. Inherent viscosities (η_inh) and weight average molecular weights (M_w) were in the range of 0.27–0.35 dL/g and 1.3 × 10⁴–2.7 × 10⁴, respectively. Future prospects are envisaged.     

Thermal characterization and thermal degradation of copolyimides containing fluorine and phosphine oxide

A series of copolyimides containing different ratios of fluorine and phosphine oxide were synthesized. The copolymers were characterized with Fourier transform infrared, differential scanning calorimetry, and thermogravimetric analysis measurements. The copolymers were thermally stable up to 700 K and exhibited glass‐transition temperatures in the range of 495–562 K. The glass‐transition temperatures of the copolymers decreased with an increase in the phosphine oxide content. The thermal decomposition behavior of the copolymers was investigated. The copolymers with higher phosphine oxide contents displayed lower onset decomposition temperatures and char yields. A new method involving the multiple‐rate isotemperature was used to define the most possible mechanism [G(α)] for the reactions. The overall kinetic model function of the thermal decomposition of these copolymers obeyed the Avrami–Erofeev model equation, G(α) = [?ln(1 ? α)]^1/m, where α is the conversion degree. The apparent kinetic parameters of the degradation processes were also obtained. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2139–2143, 2005     

Block copolymers containing pyridine moieties: Precise synthesis and applications

This review highlights the precise synthesis and application of various well-defined rod–coil and coil–coil block copolymers composed of poly(2-(or 4-)vinylpyridine) (P2VP or P4VP) block(s) with pyridine moieties. These polymers were synthesized by means of living anionic polymerization. Poly(hexyl isocyanate) (PHIC) was used as the rod-like segment, because hexyl isocyanate undergoes living anionic polymerization under carefully selected conditions. This review describes the syntheses of the block copolymers, polystyrene-b-P2VP, polystyrene-b-P4VP, polyisoprene-b-P2VP, P2VP-b-poly(methyl methacrylate), P2VP-b-poly(ethylene oxide), P2VP-b-poly(2-(N-carbazolyl)ethyl methacrylate), P2VP-b-PHIC, P2VP-b-PHIC-b-P2VP, and PHIC-b-P2VP-b-PHIC. The formation of self-organized nanostructured materials and molecular assemblies by such block copolymers and their possible applications are also described. These assemblies include monolayers, microphase-separated periodic-ordered nanostructures, micelles, polymer–metal complexes, nanoparticles, inorganic and metal layers, and nanoporous films with nanoparticles.     

Preparation and characterization of epoxy nanocomposites containing surface‐modified graphene oxide

A three‐step grafting procedure has been used to graft the epoxy monomers (DER332) and the curing agents (diamino diphenyl methane (DDM), onto graphene oxide (GO) surface. The surface modification of GO has been performed by grafting of Jeffamine D‐2000, followed with subsequent grafting of DER332 and DDM, respectively. Fourier transform spectroscopy and thermogravimetric analysis indicate successful surface modification. The resulting modified GO, that is, (DED)‐GO, can be well dispersed in the epoxy monomers. The epoxy nanocomposites containing different GO contents can then be prepared through curing processes. The dispersion of GO in the nanocomposites is characterized by transmission electron microscopy. It is found that the tensile strength and elongation at break of epoxy nanocomposite with only 0.2 wt % DED‐GO are increased by 30 and 16% as compared with the neat epoxy resin, respectively. Dynamic mechanical analysis results show that 62% increase in storage modulus and 26°C enhancement in the glass transition temperature of the nanocomposite have been achieved with the incorporation of only 0.2 wt % of DED‐GO into the epoxy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40236.     

Synthesis and characterization of new flame‐retardant poly(amide‐imide)s containing phosphine oxide and hydantoin moieties in the main chain

Six new flame‐retardant poly(amide‐imide)s (PAIs) 9a–f with high inherent viscosities containing phosphine oxide and hydantoin moieties in main chain were synthesized from the polycondensation reaction of N,N′‐(3,3′‐diphenylphenylphosphine oxide) bistrimellitimide diacid chloride 7 with six hydantoin derivatives 8a–f by two different methods such as solution and microwave assisted polycondensation. Results showed that the microwave assisted polycondensation, by using a domestic microwave oven, proceeded rapidly, compared with solution polycondensation, and was completed in about 7–9 min. All of the obtained polymers were fully characterized by means of elemental analysis, viscosity measurements, solubility test, and FTIR spectroscopy. Thermal properties and flame retardant behavior of the PAIs 9a–f were investigated using thermal gravimetric analysis (TGA and DTG) and limited Oxygen index (LOI). Data obtained by thermal analysis (TGA and DTG) revealed that these polymers showed good thermal stability. Furthermore, high char yields in TGA and good LOI values indicated that these polymers are capable of exhibiting good flame retardant properties. These polymers can be potentially utilized in flame retardant thermoplastic materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5062–5071, 2006     

Microwave-assisted synthesis and characterization of the monomeric phthalocyanines containing naphthalene-amide group moieties and the polymeric phthalocyanines containing oxa-aza bridge

New naphthalene-amide substituted phthalocyanines and oxa-aza bridge polymeric phthalocyanines were prepared by conventional and microwave methods. The chlorides of Cu(I), Ni(II) and Co(II) were employed in order to synthesize the corresponding metal phthalocyanines and Zn(CH₃COO)₂ was used for the preparation of the zinc phthalocyanines. For the preparation of the Co-containing phthalocyanines, ammonium molybdate had to be added as catalyst. In the microwave-assisted synthesis, DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) or DMAE (dimethylaminoethanol) was used as a solvent. The solubility of the phthalocyanines containing naphthalene-amide group (1a–e, 3a–e) is low in ethanol, ethyl acetate, chloroform, DMF and DMSO. Polymeric phthalocyanines (2a–e) are not soluble in common organic solvents such as chloroform, DMF and DMSO but are soluble in dilute H₂SO₄.     

Facile synthesis and thermal properties of waterglass-based silica xerogel nanocomposites containing reduced graphene oxide

In this study, new rGO-silica xerogel nanocomposites (SX-rGO) and its glass fiber reinforced composites (GFR-SX-rGO) were prepared, and its microstructure and thermal properties were evaluated. The raw material was a mixed dispersion prepared by adding 0.01–2.5?wt% of reduced graphene oxide (rGO) to waterglass (6% SiO₂). A hydrogel was prepared via sol-gel reaction of this raw material, which was then immersed in hydrochloric acid, hydrophobized in a siloxane/2-propanol reaction system, and then dried at ambient pressure to obtain a hydrophobic carbon-silica xerogel composite. The obtained samples were characterized by N₂ physisorption (at 77?K), solid ²⁹Si Magic angle spinning nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, differential scanning calorimetry, thermogravimetric analysis, hydrophobicity, and thermal conductivity. It was found that as the amount of rGO was increased, the specific surface area of the nanocomposite decreased by ~25% from 535 to 403?cm²/g, and the average pore size and pore volume were almost halved. The thermal decomposition temperature of the SX-rGO was increased markedly by the addition of rGO. Moreover, the GFR-SX-rGO-0.5 showed low density (0.208?g/cm³), high contact angle (146°) and low thermal conductivity (0.0199?W/mK).     

Novel phthalocyanines containing substituted salicyclic hydrazone-1,3-thiazole moieties: Microwave-assisted synthesis, spectroscopic characterization, X-ray structure and thermal characterization

Novel, metal-free and metallo(Cu, Co, Ni, Zn, Pb and Mn)phthalocyanine compounds were synthesized by exposure to microwave irradiation and the products purified. The newly prepared compounds were characterized using elemental analyses, IR, ¹H/¹³C NMR, ¹H–¹H COSY measurements, MS, UV–vis spectroscopy and DTA/TG analysis. The electronic spectra exhibited an intense π → π* transition with characteristic Q and B bands of the phthalocyanine core, as expected. All decomposition products obtained from DTA/TG analysis were identified; it was found that the thermal stability of each phthalocyanine compound followed the order: MnPc < Metal-free < ZnPc < PbPc < CuPc < CoPc < NiPc.     

Properties of novel polyimides containing bismaleimide and cyclic phosphine oxide

New polyimide polymers with phosphorus in the main chain were obtained from synthesized bismaleimide (EPBMI) cured with three types of curing agents: 4,4′-bismaleimidodiphenylmethane (BDM), 4,4′-bismaleimidodiphenyl- ether (BDE), and 4,4′-bismaleimidodiphenylsulfone (BDS). In addition, the compositions of the new polymers synthesized with these three curing agents (BDM, BDE, and BDS) were used to compare the curing reactivity and thermal properties of EPBMI to conventional bismaleimide (EBMI). The reactivities were measured by differential scanning calorimetry. Thermogravimetric analysis revealed the polymers, obtained through the curing reactions between EPBMI and the three curing agents mentioned also demonstrated excellent thermal properties and a high char yield compared to the EPBMI homopolymer.     

Novel vinyl-modified sepiolite-based polymer nanocomposites: synthesis and characterization

An environmental-friendly synthesis of polymer clay nanocomposites (PCNs) was carried out by incorporation of nanoclay into polymer matrix for their potential application as sorbent of metals present in aqueous media. Polyacrylonitrile was chemically grafted onto 77% vinyl triethoxysilane-modified sepiolite. The polymerization was carried out with benzoyl peroxide (BPO, C₁₄H₁₀O₄) initiator in three different weight ratios of 1.0, 2.0, and 3.0%. The maximum polymer grafting of about 83% was obtained in nanocomposite initiated by 2.0% ratio of BPO. The surface modification of nanocomposites was carried out using hydroxyl amine hydrochloride (NH₂OH·HCl). The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffractometry, thermogravimetric analysis, and Brunauer–Emmett–Teller technique. The copper removal tendency of nanocomposites was studied by atomic absorption spectroscopy. The maximum adsorption of copper was 86%, which could be achieved by nanocomposites synthesized with 2% initiator. The results have revealed the practical potential of the prepared PCN as efficient adsorbents.     

Synthesis and characterization of vinyl ester networks containing phthalonitrile moieties

A new styrenic monomer, 4-vinylphenoxyphthalonitrile, was synthesized by nucleophilic aromatic substitution of 4-vinylphenolate onto 4-nitrophthalonitrile. The new monomer was reacted with dimethacrylate-styrene resins (so-called vinyl esters) via free radical copolymerization at 90, then 120 °C with benzoyl peroxide as the initiator to form networks. The networks were further post-cured at 220, 240, or 260 °C for 4 h to convert the last portion of the methacrylates, and to partially cross-link the pendent phthalonitrile groups. A dimethacrylate-styrene network containing 30 wt% of the phthalonitrile-functional monomer exhibited a 70% reduction in peak heat release rate by cone calorimetry measured at an incident heat flux of 50 kW m⁻² relative to control vinyl ester networks. This still remains somewhat higher than peak heat release rates exhibited by brominated vinyl ester networks, but the CO/CO₂ ratio in the smoke is much lower for these non-halogenated materials.     

Structure characterization,reactivity, and thermal properties of new cyclic phosphine oxide epoxy resin containing tetra-oxirane rings

A new type of epoxy resin, which contained cyclic phosphine oxide and tetra-oxirane rings in the main chain, was synthesized. The structure of the new type of epoxy resin was confirmed by elemental analyses (EA), infrared (IR) spectroscopy, and ¹H nuclear magnetic resonance (NMR) and ¹³C-NMR spectroscopies. In addition, compositions of the new synthesized cyclic phosphine oxide epoxy resin (TGCAO) with three curing agents, for example, bis(3-aminophenyl)ethylphosphine oxide (BEMP), 4,4′-diaminodiphenylmethane (DDM), and 4,4′-diaminodiphenylsulfone (DDS) were used for making a comparison of its curing reactivity, heat, and flame retardancy with those of Epon 828 and DEN438. The reactivities were measured by differential scanning calorimetry. Through the evaluation of thermal gravimetric analysis, those polymers, which were obtained through the curing reactions between the new epoxy resin and three curing agents (BEMP, DDM, and DDS), also demonstrated adequate thermal propeties, as well as a high char yield. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1397–1409, 1998     

Novel poly(arylene ethynylene) derivatives containing main chain triphenylamine and pendent quinoxaline moieties: synthesis and elementary characterization

BACKGROUND: Various poly(arylene ethynylene)s (PAEs) have been prepared and applied as molecular wires, in sensors, in nonlinear optics and as electroluminescent materials. But, to our knowledge, there has been no attention paid to the investigation of conjugated PAEs containing both triarylamine and quinoxaline groups. The influence imparted by the introduction of triarylamine and quinoxaline on the photophysical and electrochemical properties of PAEs is of interest. RESULTS: Two kinds of novel PAE derivatives, with electron‐donating triphenylamine groups in the backbone and electron‐accepting pendent quinoxaline moieties and bearing side chains of different lengths, were successfully synthesized with the Sonogashira coupling reaction. These polymers are soluble in common organic solvents and exhibit good film‐forming ability and thermal stability. UV‐visible investigations indicate that the ground states of these materials are unaffected by the polarity of their medium. An efficient intramolecular charge transfer effect is observed from an investigation of their photoluminescence properties in different solvents. Cyclic voltammetry study reveals that these polymers possess relatively high highest occupied molecular orbital levels due to the incorporation of triphenylamine segments into the polymer backbones. CONCLUSION: Primary characterization of these novel PAE derivatives shows that they might serve as potential active materials in optoelectronic devices. Copyright © 2009 Society of Chemical Industry     

The synthesis and characterization of novel metalloporphyrazine containing crown ether linked calix[4]arene moieties

The synthesis and characterization of novel magnesium porphyrazine, peripherally symmetrically derived from 1,3-alternate 26,28-[35,36-dicyano-34,37-dithia-29,32,40,43-tetraoxa-35-en]calix[4]arene-crown-5, were carried out. This compound was prepared starting from cis-1,2-dicyano-1,2-ethylenedithiolate and 1,3-alternate 26,28-bis(5′-chloro-3′-oxapentyloxy)calix[4]arene-crown-5. The new macrocycle was characterized using the techniques of UV–vis, ¹H, ¹³C NMR, IR, MS and elemental analysis.     

Aromatic diazenes containing azulen-1-yl moieties Part 2: The synthesis,characterization, electronic spectra and basicity of novel,bis aromatic diazenes containing two azulen-1-yl moieties

Bis aromatic diazenes which possess either two identical or two different azulene-1-yl groups substituted at either 1,3 or 1,4-positions in the bridging phenylene moiety were synthesized in good yield via diazotization of the 3- or 4-azulen-1-ylazo-phenylamines followed by coupling with azulene in a buffered medium. The electronic spectra of the synthesized compounds were analyzed by comparison with those of previously published compounds. The isosbestic points obtained by protonation of the compounds enabled their pK_a values to be determined.     

Ultrasound–assisted synthesis and characterization of polymethyl methacrylate/reduced graphene oxide nanocomposites

This article reports ultrasound–assisted synthesis of polymethyl methacrylate (PMMA)/reduced graphene oxide (RGO) nanocomposites by in situ emulsion polymerization coupled with in situ reduction of graphene oxide. The thermal degradation kinetics of the nanocomposites was also assessed with Criado and Coats‐Redfern methods. Intense microconvection generated by ultrasound and cavitation results in uniform dispersion of RGO in the polymer matrix, which imparts markedly higher physical properties to resulting nanocomposites at low (≤1.0 wt %) RGO loadings, as compared to nanocomposites synthesized with mechanical stirring. Some important properties of the PMMA/RGO nanocomposites synthesized with sonication (with various RGO loadings) are: glass transition temperature (0.4 wt %) = 124.5°C, tensile strength (0.4 wt %) = 40.4 MPa, electrical conductivity (1.0 wt %) = 2 × 10^?7 S/cm, electromagnetic interference shielding effectiveness (1.0 wt %) = 3.3 dB. Predominant thermal degradation mechanism of nanocomposites (1.0 wt % RGO) is 1D diffusion with activation energy of 111.3 kJ/mol. © 2017 American Institute of Chemical Engineers AIChE J, 64: 673–687, 2018     

Impact modified epoxy/montmorillonite nanocomposites: synthesis and characterization

Diglycidyl ether of bisphenol A type epoxy resin-polyether polyol-organically treated montmorillonite ternary nanocomposites were synthesized in this study. The effects of addition of polyether polyol as an impact modifier on morphological, thermal and mechanical properties of nanocomposites were investigated by X-ray diffraction, scanning electron microscopy (SEM), differential scanning calorimetry, impact and tensile testing. The results showed that organically treated montmorillonite is intercalated by epoxy, since the interlayer spacing expanded from 1.83 to 3.82 nm upon nanocomposite synthesis. The addition of polyether polyol impact modifier had no effect on the interlayer spacing. SEM examination showed that polyol forms an immiscible phase in the epoxy matrix. Thermal characterization of nanocomposites indicated an increase in T_g with respect to both polyether polyol and montmorillonite contents. The impact strength of the samples with no clay was improved approximately 160% upon adding 7 wt% polyether polyol. In polyether polyol modified nanocomposites, the impact and tensile strengths decreased with respect to increasing amount of montmorillonite and showed a maximum with respect to the polyether polyol content at constant clay loading. The Young's modulus of the nanocomposites exhibited an increase with respect to the montmorillonite loading and showed a maximum with respect to the polyol content at each clay loading.     

Microwave‐assisted synthesis and characterization of polyimide/functionalized MWCNT nanocomposites containing quinolyl moiety

Polyimide‐MWCNT nanocomposites were prepared by the reaction of a heterocyclic diamine monomer of bis(4‐amino‐3,5‐dimethylphenyl)‐2‐chloro‐3‐quinolylmethane (BACQM), pyromellitic dianhydride (PMDA) with unmodified MWCNT (MWCNT), acid‐functionalized MWCNT (acid‐MWCNT) or amine‐functionalized MWCNT (amine‐MWCNT) using microwave irradiation as well as by the conventional method. The structure of the monomer was confirmed by FTIR, ¹H‐NMR, and ¹³C‐NMR spectral techniques. The glass transition temperature (T_g) of the MWCNTs/polyimide nanocomposite was found to be higher than that of the unfilled polyimide system. The T_g's of both systems were higher when prepared with the microwave method than the conventional synthesis. The T_g's of the nanocomposites using acid and amine functionalized MWCNTs are greater than 300°C, in both methods. This is attributed to the presence of hydrogen bond and strong covalent bond in both the acid‐MWCNT/polyimide and amine‐MWCNT/polyimide systems. The morphological studies of the nanocomposites synthesized using microwave irradiation show that a distinct MWCNT nanofibrillar network is formed in the matrix when MWCNT or acid‐MWCNT is used. A homogeneous morphology, without distinct nanotube domains is seen when the amine‐MWCNT is covalently linked to the polymer. POLYM. COMPOS., 37:2417–2424, 2016. © 2015 Society of Plastics Engineers