Synthesis and characterization of a novel terephthalate‐bridged ladderlike polymethylsiloxane

A novel soluble terephthalate‐bridged ladderlike polymethylsiloxane was synthesized successfully by stepwise coupling polymerization in three steps, including hydrosilylation coupling, hydrolysis and polycondensation. The bis(3‐methyldichlorosilylpropyl) terephthalate monomer was first synthesized by hydrosilylation reaction in the presence of dicyclopentadienylplatinum(II) chloride (Cp₂PtCl₂) catalyst. The structures of the monomer and the polymer were characterized by FTIR, ¹H NMR, ¹³C NMR and ²⁹Si NMR spectroscopy, mass spectrometry, X‐ray diffraction, differential scanning calorimetry, vapour pressure osmometry and gel permeation chromatography. Characterization data indicate that the synthesized polymer possesses an ordered ladderlike structure. © 2000 Society of Chemical Industry     

Preparation of PMMA–PS–PMMA via combination of anionic and photoinduced charge‐transfer polymerization

PMMA–PS–PMMA triblock copolymers were prepared by the combination of an anionic mechanism with charge‐transfer polymerization. Polystyrene with aromatic tertiary amino groups at both ends (PS_ba) was synthesized first by the reaction of a living polystyrene macrodianion with excess p‐(dimethylamino)benzaldehyde; then, the PS_ba was constituted into a binary system with benzophenone (BP) to initiate the polymerization of methyl methacrylate (MMA) under UV irradiation. The intermediate and resulting block copolymers were characterized by GPC, IR, and ¹H‐NMR. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2072–2076, 1999     

Synthesis and characterization of a novel silicon‐containing polytriazole resin

4,4′‐Diazidomethylbiphenyl (DAMBP) and poly(dimethylsilylene‐ethynylenephenyleneethynylene) (PDMSEPE) were thermally polymerized to form a novel silicon‐containing polytriazole resin (PDMSEPE‐DAMBP) by 1,3‐dipolar cycloaddition. Differential scanning calorimetry, FTIR, and ¹³C‐NMR were used to characterize the curing behaviors of PDMSEPE‐DAMBP resins. The results indicated that the resins could cure at temperatures as low as 80°C. Dynamic mechanical analysis showed that there was a glass transition at 302°C for the cured PDMSEPE‐DAMBP resin. The carbon fiber (T700) reinforced PDMSEPE‐DAMBP composites exhibited excellent mechanical properties at room temperature and high property retention at 250°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Reactivity ratios of free monomers and their charge‐transfer complex in the copolymerization of N‐butyl maleimide and styrene

As for the charge‐transfer complex (CTC) formed by N‐butyl maleimide (NMBI) and styrene in chloroform, the complex formation constant was determined by ¹H‐NMR of Hanna–Ashbaugh. The copolymerization of NBMI (NBMI, M₁) and styrene (St, M₂) in chloroform using AIBN as an initiator was investigated. On the basis of the kinetic model proposed by Shan, the reactivity ratios of free monomers and CTC in the copolymerization were calculated to be r₁₂ = 0.0440, r₂₁ = 0.0349, r_1C = 0.00688, r_2C = 0.00476, and the ratios of rate constants were obtained to be k_1C/k₁₂ = 6.40, k_2C/k₂₁ = 7.33. In addition, the copolymer was characterized by IR, ¹H‐NMR, DSC, and TGA. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3007–3012, 2002; DOI 10.1002/app.2330     

Synthesis and characterization of novel chain‐extended bismaleimides containing fluorenyl cardo structure

Novel fluorenyl cardo chain‐extended bismaleimides (FCCEBMIs) were synthesized by reacting maleic anhydride with fluorenyl cardo diamine and different dianhydrides. FCCEBMIs were characterized by FT‐IR spectra (FT‐IR), ¹H NMR, and elemental analysis. All FCCEBMI monomers were readily soluble in a variety of organic solvents, such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethyl acetamide, chloroform (CHCl₃), methylene chloride (CH₂Cl₂), dimethyl sulfoxide, and tetrahydrofuran when compared with 9,9‐bis(4‐maleimidophenyl) fluorene. Curing process was investigated by differential scanning calorimetry. Thermal properties of the cured FCCEBMIs were characterized by thermogravimetry analysis, the cured products are stable up to 430°C. The results show that the FCCEBMIs with imide structure improve significantly the solubility of bismaleimide (BMI) in organic solvents without sacrificing thermal properties of cured BMIs. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of a novel siloxane‐imide‐containing polybenzoxazine

A novel siloxane‐imide‐containing polybenzoxazine based on N,N′‐bis(N‐phenyl‐3,4‐dihydro‐2H‐benzo[1,3]oxazine)‐5, 5′‐bis(1,1′,3,3′‐tetramethyldisiloxane‐1,3‐diyl)‐bis(norborane‐2,3‐dicarboximide) (BZ‐A1) was successfully synthesized. The thermal properties of BZ‐A1 are superior to those of conventional polybenzoxazines lacking siloxane groups. Polymerized BZ‐A1 possesses extremely low surface free energy (γ_s = 15.1 mJ m^?2) after curing at 230 °C for 1 h. Moreover, the surface free energy of polymerized BZ‐A1 is more stable than conventional bisphenol A‐type polybenzoxazine during thermal curing and annealing processes, indicating that polymerized BZ‐A1 is more suitable for applications requiring low surface free energy materials for high temperatures over long periods of time. Copyright © 2010 Society of Chemical Industry     

Surface photografting polymerization of vinyl acetate,maleic anhydride,and their charge‐transfer complex. VI. Charge‐transfer complex (2)

The photografting copolymerization of a low‐density polyethylene/vinyl acetate (VAC)–maleic anhydride (MAH) binary monomer system was studied from the perspective of dynamics. The total conversion percentage (CP) and grafting conversion percentage (CG) were measured by gravimetry. On the basis of plots of CP and CG as functions of the polymerization time, the total polymerization rate (RP) and grafting polymerization rate (RG) were calculated. In addition, the apparent activation energy (E_a) and the reaction orders of the photografting polymerization under different reaction conditions, such as the total monomer concentration and the concentration of benzophenone (BP), were determined also. The results showed that, in comparison with the photografting polymerization of the two single monomers (VAC and MAH), RP and RG noticeably increased for the VAC–MAH binary monomer system. When the total monomer concentration was kept at 4M, the apparent E_a's of the three photografting polymerization systems were as follows: for VAC ([MAH]/[VAC] = 0/4), E_a's for the total polymerization and grafting polymerization were 41.00 and 43.90 kJ/mol, respectively; for MAH ([MAH]/[VAC] = 4/0, E_a's were 39.65 and 43.23 kJ/mol, respectively; and for the VAC–MAH binary monomer system, E_a's were 34.35 and 40.32 kJ/mol, respectively. These results suggested that the polymerization of the binary system occurred more readily than the other two. The reaction orders of RP with respect to the total monomer concentration of the monomers and the concentration of BP were 1.34 and 0.81, respectively. According to these investigations, it could be inferred that in the binary monomer system, both the free monomers and charge‐transfer complex took part in the polymerization; to the termination of the propagating chains, two possible pathways, unimolecular termination and bimolecular termination, coexisted in this binary monomer system. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 910–915, 2005     

Surface photografting polymerization of vinyl acetate,maleic anhydride,and their charge‐transfer complex. VIII. Charge‐transfer complex (4)

In view of the complexity of surface photografting polymerization of vinyl acetate/maleic anhydride (VAC/MAH) binary monomer systems, a novel method was adopted in the present article to obtain insight into the relevant grafting copolymerization mechanism. This method includes two steps: semibenzopinacol dormant groups were first introduced onto LDPE film by UV‐irradiation and then thermally reactivated to produce LDPE macromolecular free radicals, which initiated the grafting copolymerization of VAC and MAH. It was demonstrated that, in the first step, the solvent used to introduce benzophenone (BP) to LDPE film largely affected the subsequent grafting copolymerization, which was closely related to the affinity of the solvent toward the substrate. The monomer feed composition had considerable influence on both the grafting and nongrafting copolymerization; however, the maximum copolymerization rates did not appear in the polymerization system with [VAC]/[MAH] being 1 : 1, but, in the system with a bit more VAC than MAH, as the total monomer concentration was raised, the maximum copolymerization rates tended to appear in the system with [VAC] equal to [MAH]. The relationship between the total copolymerization rate (RP) and monomer concentration was determined to be LnRP ∝ [VAC + MAH]^1.83. All of these results indicated that both charge transfer (CT) complex formed by VAC and MAH and free monomers took part in grafting copolymerization. This feature differentiated the surface grafting copolymerization of VAC/MAH from the well‐studied thermally induced alternating copolymerization of VAC/MAH. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Surface photografting polymerization of vinyl acetate,maleic anhydride,and their charge‐transfer complex. V. Charge‐transfer complex (1)

In previous studies, the photografting polymerization of vinyl acetate (VAC) and maleic anhydride (MAH) was investigated systematically. After that, to increase the grafting rate and efficiency and make the project more practicable, a VAC–MAH binary monomer system was employed for simultaneous photografting onto the surface of low‐density polyethylene film. The effects of several crucial factors, including the composition and total concentration of the monomer solution and different types of photoinitiators and solvents, on the grafting polymerization were investigated in detail. The conversion percentage (CP), grafting efficiency (GE), and grafting percentage were measured by gravimetry. The results showed that the monomer composition played a big part in this binary system; appropriately increasing the content of MAH in the monomer feed was suited for grafting polymerization. The growth of the total monomer concentration, however, made the copolymerization faster and was unfavorable for grafting polymerization. The three photoinitiators—2,2‐dimethoxy‐2‐phenylacetophenone (Irgacure 651), benzoyl peroxide, and benzophenone (BP)—led to only slight differences in CP, but for GE, BP was the most suitable. As for the different solvents—acetone, ethyl acetate, tetrahydrofuran (THF), and chloroform—using those able to donate electrons (acetone and THF) resulted in relatively higher CPs; on the contrary, the use of the other solvents made GE obviously higher, and this should be attributed to the charge‐transfer complex (CTC) that formed in this system. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 903–909, 2005     

Synthesis of high metal‐complexation linear elastomers containing sym‐1,2,4,5‐tetrazine rings

We report the synthesis of polyurethane‐urea elastomers containing 1,2,4,5‐tetrazine covalently reacted within the main chains of the polymers. Our study investigates the synthesis of 3,6‐diamino‐1,2,4,5‐tetrazine (DAT), the polymerization reaction conditions for reacting DAT into the backbone of segmented polyurethane elastomers, and the metal‐complexation capabilities of tetrazine‐containing elastomers with cobalt (II) chloride. Tetrazines are highly colored and electro‐active heterocyclic moieties, which have a very high electron affinity which make them reducible at high to very high potentials. Upon complexation with metals, we observed a strong color shift of the polymers from deep red to blue indicating the binding efficacy for the polymers. We quantified the metal‐complexation capability of the tetrazine elastomers and determined a molar ratio of approximately two metal atoms per tetrazine allowing us to provide a plausible complexation mechanism for the active polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of hyperbranched cationic polyelectrolytes via aqueous self‐condensing atom transfer radical polymerization

The hyperbranched cationic polyelectrolytes (PDMEAB) were directly prepared via the CuBr/ligand‐catalyzed (ligand = 2,2′‐bipyridine or pentamethyldiethylenetriamine) aqueous self‐condensing atom transfer radical polymerization (SCATRP) of a novel inimer, N,N‐dimethyl‐N‐(2‐methacryloyloxy)ethyl‐N‐(2‐bromoisobutyryloxy)ethyl ammonium bromide (DMEAB). Elemental analysis and nuclear magnetic resonance (NMR) spectroscopy confirmed the structure of DMEAB. The hyperbranched architecture and number‐average degree of polymerization (DP_n) of the PDMEAB was studied by ¹H‐ and ¹³C‐NMR. The kinetic results suggested that the DP_n of the hyperbranched PDMEAB grew gradually in the initial stage and exponentially in the later stage. The differential scanning calorimetry (DSC) showed that the glass transition temperature of the hyperbranched PDMEAB was much lower than that of the linear analogue. The solution rheometry showed that the aqueous PDMEAB solutions approximately underwent a Newtonian behavior and their shear viscosity maintained almost constant upon the addition of NaCl because of the spherical conformations of the hyperbranched cationic polyelectrolytes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis,characterization, and electroluminescent properties of a novel perylene‐containing copolyimide

A novel diphenylfluorene‐based Cardo copolyimide containing perylene (PFB5) was designed and synthesized by polycondensation of a diamine 4,4′‐(9H‐fluoren‐9‐ylidene)bisphenylamine with perylene dianhydride and another dianhydride in m‐cresol with isoquinoline as a catalyst at 200°C. PFB5 was characterized by FTIR, EA, GPC, TGA, DSC, UV‐vis, and PL. Because of the existence of the bulky diphenylfluorene units in the backbone, PFB5 showed high thermal stability and good solubility in common solvents such as chloroform. Solubility of PFB5 in low boiling point solvents allows direct spin coating of the polymer films, which exhibit intense photo‐ and electroluminescence (EL) in the visible range. This nonconjugated polymer could be used as emitting and electron‐hole transporting layers in polymer electroluminescent devices (PELDs). EL properties of the unilayer ELDs based on PFB5 are discussed. The device emitted a greenish yellow light. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 786–791, 2003     

Synthesis and photoconductive characteristics of biphenylporphyrin‐containing poly(amic acid)s and polyimides

Three series of biphenylporphyrin (BPP)‐containing poly(amic acid)s (PAAs) were synthesized and converted into heat‐treated polyimides (HPIs) and chemically treated polyimides (CPIs). Viscosity measurements, UV–vis and IR spectroscopies, as well as thermogravimetric analysis (TGA), were used to characterize the structures of the polymers. UV–vis spectra revealed that the BPP units formed aggregates in PAA and CPI films, rather than in HPI films. Photoinduced discharge was used to characterize the photoconductive properties of these polymer films. It was found that the photosensitivity was greatly enhanced by introducing BPP units into the polymer chains. For these three series of polymers, the photosensitivity increased in the order PAA < HPI < CPI according to the content of BPP in the polymers. The photoconductive characteristics were interpreted by the intrinsic π—π* process of BPP aggregation and the extrinsic process of charge‐transfer complex formation. The best photoconductive performances of the CPIs were attributed to the existence of two charge‐carrier‐generation processes. Copyright © 2004 Society of Chemical Industry     

Kinetics and mechanism of the charge‐transfer polymerization of methyl methacrylate initiated with n‐butyl amine and carbon tetrachloride catalyzed by palladium dichloride

We studied the kinetics and mechanism of the charge‐transfer polymerization of methyl methacrylate (MMA) initiated with n‐butyl amine (BA) and carbon tetrachloride (CCl₄) catalyzed by palladium dichloride (PdCl₂ or Pd^II) in a dimethyl sulfoxide medium by using a dilatometric technique at 60°C. The rate of polymerization (R_p) was a function of [MMA], [BA], [CCl₄], and [Pd^II]. The kinetic data indicated a mechanism involving the possible participation of the charge‐transfer complex formed between the {BA–Pd^II} complex and CCl₄ or monomer in the polymerization of MMA. In the absence of either CCl₄ or BA, no polymerization of MMA was observed under these experimental conditions. R_p was inhibited by hydroquinone; this suggested a free‐radical initiation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and properties of photoluminescent copolymer containing 1,3,4‐oxadiazole and carbazole rings

The luminescent copolymer 2‐phenyl‐5‐[3′‐(methacrylamido)phenyl]‐1,3,4‐oxadiazole and vinylcarbazole (PMAPO–VCZ), combining hole‐facilitating moiety, carbazole ring, and electron‐facilitating moiety, 1,3,4‐oxadiazole, as side groups, was synthesized by a radical polymerization of the olefinic monomer PMAPO and VCZ. For comparison, the homopolymer P‐PMAPO was also synthesized by similar procedures. The solubility, thermal, and optical properties of the copolymers were investigated. The synthesized copolymer was soluble in common organic solvents but the homopolymer of PMAPO was dissolved only by hot THF. Thermogravimetric analysis and differential scanning calorimetry measurements showed that the copolymer and homopolymer exhibit good thermal stability up to 360 and 340°C with glass‐transition temperatures higher than 105 and 65°C, respectively. The photoluminescence properties were investigated. The results showed that the copolymer emits blue and blue‐green light and the emission spectra of monomer and polymers exhibit obvious solvent effect. With the increase of polarity of solvents, the fluorescence spectra distinctly change, appearing with a red shift at room temperature. The concentration‐dependent emission spectra change significantly with the increase of concentration. In addition, when N,N‐dimethylaniline (DMA) was gradually added to the solution of copolymers, the emission intensity of fluorescence was dramatically increased. However, when the concentration of DMA was increased beyond a certain level, the emission intensity of fluorescence gradually decreased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2777–2783, 2004     

Synthesis and characterization of novel polyurethanes based on fluorine‐containing polyphosphazene

Fluorine‐containing poly[bis‐(2,2,3,3,4,4,5,5‐octafluoro‐1‐pentanol)_1.6 (4‐hydroxybutaneoxy)_0.4 phosphazene] (OFHBP) was synthesized and characterized by Fourier transform infrared (FTIR) spectra, nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The obtained OFHBP was used as a cross‐linker to prepare a series of novel polyurethanes (PUPFs). The composition of the PUPFs was confirmed by FTIR and elemental analysis (EA). The crystalline structure and microstructure of the PUPFs were examined by X‐ray diffraction (XRD) and atomic force microscopy (AFM). The thermal and tensile properties of the PUPFs were characterized by differential scanning calorimetry (DSC) and tensile testing. In addition, the surface energy of the PUPFs was also evaluated by contact angle measurements (CA). The results showed that glass transition temperature of the PUPF‐4 was decreased by 15°C, elongation at break was improved by 61% and a 41% decrease in surface energy in comparison with conventional polyurethane. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of triphenyl phosphine oxide‐containing polymers via atom transfer radical polymerization

Bis[(4 ‐β‐(2‐bromopropanoate)ethoxy)phenyl]phenylphosphine oxide was used for the first time as the initiator of atom transfer radical polymerization of styrene and methyl methacrylate in the presence of CuBr/N, N,N′, N″, N″‐pentamethyldiethylenetriamine as catalyst/ligand and dimethyl sulfoxide as solvent. The presence of phosphine oxide linkages in the backbone gives the polymers special properties; low T_g, high char yield, and decreases the oxygen induction time value. A linear increase of number average molecular weight (M_n) versus monomer conversion was observed, and the molecular weight distribution was relatively narrow (M_w/M_n = 1.1–1.3). FTIR, ¹HNMR, gel permeation chromatography, ultraviolet spectroscopies were used for the characterization of the related polymers. The thermal properties of these polymers were investigated by differential scanning calorimetry and thermogravimetric analysis. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of a novel nitrogen‐containing flame retardant

The lowering of ignitability and flammability of polyethylene (PE) and the production of fire‐retarding materials has become an urgent problem because of the demand of fire safety. In our article, a new charring agent (CA), a derivative of triazines, was synthesized by charging 2‐amino‐4,6‐dichloro‐s‐triazines and diethylenetriamine into a reactor to conduct the solution polycondensation reaction, and the synthetic conditions of monomer and CA, such as temperature, time, etc., were investigated. Both the monomer and the resulting polymer were characterized by mass spectrum (MS), Fourier transform infrared (FTIR) spectroscopy, ¹H? NMR, and elemental analysis. The intrinsic viscosities and flame‐retardancy property of CA were also studied. It was found that the incorporation of ammonium polyphosphate (APP) and CA into low‐density polyethylene (LDPE) has a distinct effect on thermal and flame‐retardancy behavior. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1556–1561, 2004     

Layer‐by‐layer films based on charge transfer interaction of ϕ‐conjugated poly(dithiafulvene) and incorporation of gold nanoparticles into the films

Layer‐by‐layer (LBL) self‐assembled ultrathin films were prepared via consecutively alternating immersion of substrates into solutions of electron donor, poly(dithiafulvene) (PDF), and electron acceptor, poly(hexanyl viologen) (6‐VP). The charge transfer (CT) interaction formed at solid–liquid interfaces between the backbones of the electron acceptor and donor polymers was the driving force of the alternative deposition. The sandwich heterostructure of the LBL film led to electrical anisotropy in the directions parallel and perpendicular to the film surfaces. Incorporation of gold nanoparticles into the LBL films was investigated by reducing gold ions with the PDF layers already deposited on the film surfaces, or depositing PDF‐protected gold colloidal solution as the electron donor layers directly. The influence of the gold nanoparticles on the electrical anisotropy of the LBL films was also illustrated in this research. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1608–1615, 2007