首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 312 毫秒
1.
Several new poly(amide imide)s were synthesized through the polycondensation reactions of bis(4‐trimellitimidophenyl) sulfone [N,N′‐(4,4′‐diphenylsulfone) bistrimellitimide] with a number of hydantoin derivatives in a medium consisting of thionyl chloride, N‐methyl‐2‐pyrrolidone, and pyridine. The polycondensations produced a series of novel poly(amide imide)s in high yields with inherent viscosities of 0.20–0.46 dL/g. The resulting poly(amide imide)s were characterized with elemental analysis, viscosity measurements, thermogravimetric analysis, derivative thermogravimetry, solubility testing, and Fourier transform infrared spectroscopy. All the polymers were soluble at room temperature in polar solvents such as N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, and N‐methyl‐2‐pyrrolidone. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1776–1782, 2005  相似文献   

2.
The specific features of free‐radical polymerization of methyl methacrylate in the presence of a new initiating system, benzoyl peroxide‐N,N‐dimethyl‐N‐(methylferrocenyl)amine, are studied. Mutual influence of ferrocenyl‐ and amine groups on kinetic parameters of polymerization and on the microstructure of the resulting polymers is found. It is shown that the polymer obtained in the presence of this initiating system has predominantly syndiotactic structure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 724–727, 2007  相似文献   

3.
The graft polymerization of methyl methacrylate and butyl acrylate onto poly(vinyl chloride‐co‐vinyl acetate) with atom transfer radical polymerization (ATRP) was successfully carried out with copper(I) thiocyanate/N,N,N,N,N″‐pentamethyldiethylenetriamine and copper(I) chloride/2,2′‐bipyridine as catalysts in the solvent N,N‐dimethylformamide. For methyl methacrylate, a kinetic plot of ln([M]0/[M]) (where [M]0 is the initial monomer concentration and [M] is the monomer concentration) versus time for the graft polymerization was almost linear, and the molecular weight of the graft copolymer increased with increasing conversion, this being typical for ATRP. The formation of the graft polymer was confirmed with gel permeation chromatography, 1H‐NMR, and Fourier transform infrared spectroscopy. The glass‐transition temperature of the copolymer increased with the concentration of methyl methacrylate. The graft copolymer was hydrolyzed, and its swelling capacity was measured. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 183–189, 2005  相似文献   

4.
In this study, novel thermolatent cationic initiators based on dibenzocycloheptenyl phosphonium salts ( 1a , 1b , 1c , 1d , 2a , and 3a ) were synthesized and their efficiency was examined in bulk polymerization of glycidyl phenyl ether (GPE). The polymerization of GPE was performed with 1 mol % of dibenzocycloheptenyl triphenylphosphonium salts ( 1a – 1d ) with different counter anions (SbF6?, PF6?, AsF6?, and BF4?) at 25–200°C for 1 h. The order of initiator activity was found as 1a > 1d > 1b > 1c . To examine the effect of phosphine moiety, the activity of 1a was compared with dibenzocycloheptenyl‐tri‐n‐butylphosphonium hexafluoroantimonate ( 2a ). The order of initiator activity was observed as 1a > 2a. The initiator activity of 1a was compared with that of 10,11‐dihydro‐dibenzocycloheptenyltriphenylphosphonium hexafluoroantimonate ( 3a ) to understand the effect of extended conjugation in dibenzocycloheptenyl ring. In general, with the increase in the polymerization temperature, conversion (%) also increases. The solubility of initiators in various solvents and epoxy monomers was also examined. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

5.
An amphoteric water‐soluble copolymer, polyacrylamide/[α‐N,N‐dimethyl‐N‐(3‐(β‐carboxylate)acrylamino)propyl] ammonium ethanate (PAM/DAE) was synthesized and used as a dispersion agent for BaTiO3 particles. PAM/DAE was prepared from acrylamide and [α‐N,N‐dimethyl‐N‐(3‐(β‐carboxylate)acrylamino)propyl] ammonium ethanate in a basic condition through a free‐radical polymerization. The structure of this copolymer was verified by IR and 1H‐NMR spectra. The dispersing effects of PAM/DAE were examined by measuring the viscosity and sedimentation of BaTiO3 suspensions, and by analyzing the particle size. The results indicate that this copolymer could uniformly disperse the particles, and the resulting suspensions were less viscous, more stabilized, and contained powder with smaller particle size. The dispersing/stabilizing ability of PAM/DAE is close to, or slightly better than, that of a commercial dispersant, ammonium salt of poly(methacrylic acid). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1443–1450, 2005  相似文献   

6.
Thermoresponsive and pH‐responsive gels were synthesized from N‐isopropyl acrylamide (NIPA) and N,N′‐dimethyl aminoethyl methacrylate (DMAEMA) monomers. Gelation reactions were carried out with both conventional free‐radical polymerization (CFRP) and controlled free‐radical polymerization [reversible addition fragmentation transfer (RAFT)] techniques. The CFRP gels were prepared by polymerizing mixtures of NIPA and DMAEMA in 1,4‐dioxane in presence of N,N'‐methylene bisacrylamide (BIS) as cross‐linker. The RAFT gels were prepared by a the polymerization of NIPA via a similar process in the presence of different amounts of poly(N,N′‐dimethyl aminoethyl methacrylate) macro chain‐transfer agent and the crosslinker. These gels were characterized by scanning electron microscopy (SEM) and differential scanning calorimetry. SEM analysis revealed a macroporous network structure for the RAFT gels, whereas their volume phase‐transition temperatures (VPTTs) were found to be in the range 32–34°C, close to that of poly(N‐isopropyl acrylamide) gels. However, the CFRP copolymer gels exhibited a higher VPTT; this increased with increasing DMAEMA content. The RAFT gels exhibited higher swelling capabilities than the corresponding CFRP gels and also showed faster shrinking–reswelling behavior in response to changes in temperature. All of the gels showed interesting pH‐responsive behavior as well. The unique structural attributes exhibited by the RAFT gels can potentially open up opportunities for developing new materials for various applications, for example, as adsorbents or carrier of drugs or biomolecules. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42749.  相似文献   

7.
Novel N‐phenacylammonium salts [N‐(α‐benzoylbenzyl)‐, N‐(1‐benzoylethyl)‐, N‐phenacyl‐, pyrazinium, 3‐bromoquinolinium, benzothiazolium, or p‐cyanopyridinium hexafluoroantimonates] were synthesized by the reaction of α‐benzoylbenzyl bromide, 2‐bromopropiophenone or phenacylbromide, and the corresponding N‐hetero aromatic compound, followed by anion exchange with KSbF6. These N‐phenacylammonium salts showed higher activity than previously reported N‐benzyl‐2‐cyanopyridinium hexafluoroantimonate in the photopolymerization of epoxides. Further, these N‐phenacylammonium salts served as photoradical and thermal cationic initiators as well as photocationic initiators. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3470–3476, 2004  相似文献   

8.
Pyromellitic dianhydride (benzene‐1,2,4,5‐tetracarboxylic dianhydride) (1) was reacted with several amino acids in acetic acid and the resulting imide‐acid [N,N′‐(pyromellitoyl)‐bis‐L ‐amino acid diacid] (4a–4d) was obtained in high yield. The direct polycondensation reaction of these diacids with 4,4′‐thiobis(2‐tert‐butyl‐5‐methylphenol) (5) was carried out in a system of tosyl chloride(TsCl), pyridine, and N,N‐dimethyl formamide (DMF) to give a series of novel optically active poly(esterimide)s. Step‐growth polymerization was carried out by varying the time of heating and the molar ratio of TsCl/diacid, and the optimum conditions were achieved. These new chiral polymers were characterized with respect to chemical structure and purity by means of specific rotation experiments, FTIR, 1H‐NMR, X‐ray diffraction, elemental, and thermogravimetric analysis (TGA) field emission scanning electron microscopy (FE‐SEM) techniques. These polymers are readily soluble in many polar organic solvents like DMF, N,N‐dimethyl acetamide, dimethyl sulfoxide, N‐methyl‐2‐pyrrolidone, and protic solvents such as sulfuric acid. TGA showed that the 10% weight loss temperature in a nitrogen atmosphere was more than 390°C; therefore, these new chiral polymers have useful levels of thermal stability associated with good solubility. Furthermore, study of the surface morphology of the obtained polymers by FE‐SEM showed that each polymers exhibit nanostructure morphology. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

9.
The atom transfer radical polymerization (ATRP) of lauryl methacrylate (LMA) with an ethyl 2‐bromobutyrate/CuCl/N,N,N,N,N″‐pentamethyldiethylenetriamine initiation system was successfully carried out in toluene, and poly(lauryl methacrylate) with a low polydispersity (1.2 < weight‐average molecular weight/number‐average molecular weight < 1.5) was obtained. Plots of ln ([M])0/([M]) versus time and plots of the molecular weight versus conversion showed a linear dependence, indicating a constant number of propagating species throughout the polymerization. The rate of polymerization was 0.56‐order with respect to the concentration of the initiator and 1.30‐order with respect to the concentration of the Cu(I) catalyst. In addition, the effect of the solvent on the polymerization was investigated, and the thermodynamic data and activation parameters for the solution ATRP of LMA were reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1117–1125, 2003  相似文献   

10.
A terpolymer, obtained by the free‐radical terpolymerization of 2‐(N,N‐dimethylamino)ethyl methacrylate (DMMA), methyl methacrylate(MMA), and isobutyl methacrylate (IBMA), was allowed to react with hydrogen peroxide, chloroacetic acid, and diethyl sulfate to form the corresponding modified terpolymers: (1) N,N‐dimethyl‐N‐(2‐methacryloyloxyethyl)amine N‐oxide, MMA and IBMA (DMANO series); (2) N‐(carboxymethyl)‐N,N‐dimethyl‐ N‐(2‐methacryloyloxyethyl)ethyl ammonium, MMA and IBMA (CDME series); and (3) N‐(ethyl)‐N,N‐dimethyl‐N‐(2‐methacryloyloxyethyl)ethyl ammonium ethylsulfonate, MMA and IBMA (EDMEES series), respectively. The terpolymer compositions were determined using 13C NMR spectrometry. Surface free energies of the terpolymers were estimated by measuring the contact angles of water and methylene iodide on the three series films (DMANO, CDME, and EDMEES), and the effect of the N‐oxide group on wettability was discussed. It was found that the upper surface of the films for the DMANO and CDME series are more hydrophobic than that for the EDMEES series. Notably, elongation to break for the DMANO series was relatively larger than that for the CDME series because of the water bound to the N‐oxide functional group. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1235–1243, 2005  相似文献   

11.
A novel gel polymer electrolyte (GPE) which is based on new synthesized boron‐containing monomer, benzyl methacrylate, 1 m LiClO4/N,N‐dimethylformamidel liquid electrolyte solution is prepared through a one‐step synthesis method. The boron‐containing GPE (B‐GPE) not only displays excellent mechanical behavior, favorable thermal stability, but also exhibits an outstanding ionic conductivity of 2.33 mS cm?1 at room temperature owing to the presence of anion‐trapping boron sites. The lithium ion transference in this gel polymer film at ambient temperature is 0.60. Furthermore, the symmetrical supercapacitor which is fabricated with B‐GPE as electrolyte and reduced graphene oxide as electrode demonstrates a broad potential window of 2.3 V. The specific capacitance of symmetrical B‐GPE supercapacitors retains 90% after 3000 charge–discharge cycles at current density of 1 A g?1.  相似文献   

12.
Three N,N′‐bis(diphenylsilyl)tetraphenylcyclodisilazane‐based derivatives, N,N′‐bis(3,3,3‐trimethyl‐1,1‐diphenyl‐disiloxanyl)tetraphenylcyclodisilazane, N‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl)‐N′‐(3,3,3‐trimethyl‐1,1‐diphenyl‐disiloxanyl)‐tetraphenylcyclodisilazane, and N,N′‐bis‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl) tetraphenylcyclodisilazane, were synthesized. These compounds were synthesized in an easy and effective route. X‐ray single‐crystal diffraction analyses showed that the four‐member rings were planar rings, and the structures are different with the different substitution. The compound N,N′‐bis‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl) tetraphenylcyclodisilazane was added to the silicone rubber as additive to enhance the thermal stability greatly increased the thermal stability of the silicone rubber, without altering the glass transition temperature. The weight loss at 350°C in nitrogen atmosphere for 24 h reduced from 55.8% for 0 wt % to 9.8% for 10 wt % addition N,N′‐Bis‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl)tetraphenylcyclodisilazane. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   

13.
Trimellitic anhydride was reacted with 4,4′‐diaminodiphenyl ether in a mixture of acetic acid and pyridine (3 : 2) at room temperature and was refluxed at 90–100°C, and N,N′‐(4,4′‐diphenylether) bistrimellitimide (3) was obtained in a quantitative yield. 3 was converted into N,N′‐(4,4′‐diphenylether) bistrimellitimide diacid chloride (4) by a reaction with thionyl chloride. Then, six new poly(amide imide)s were synthesized under microwave irradiation with a domestic microwave oven through the polycondensation reactions of 4 with six different derivatives of 5,5‐disubstituted hydantoin in the presence of a small amount of a polar organic medium such as o‐cresol. The polycondensation proceeded rapidly and was completed within 7–10 min, producing a series of new poly(amide imide)s in high yields with inherent viscosities of 0.27–0.66 dL/g. The resulting poly(amide imide)s were characterized by elemental analysis, viscosity measurements, differential scanning calorimetry, thermogravimetric analysis, derivative thermogravimetry, solubility testing, and Fourier transform infrared spectroscopy. All the polymers were soluble at room temperature in polar solvents such as N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, and N‐methyl‐2‐pyrrolidone. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3447–3453, 2004  相似文献   

14.
The aim of present study is to examine the photo-initiation efficiency of N,N-dimethylacrylamide-based allylic ammonium salt as one component addition-fragmentation agent (cationic photoinitiator cum radical source) in free radical accelerated cationic polymerization. Novel addition-fragmentation agent (AFA), 2-(N,N-dimethylcarboxy-3-propenyl)(phenylcarbonyl-4-phenylene) dimethyl ammonium hexafluoroantimonate (DMPDA) was synthesized as cationic photoinitiator and its initiation efficiency was examined in polymerization of cyclohexene oxide (CHO), isobutyl vinyl ether (IBVE), and n-butyl vinyl ether (n-BVE) in CH2Cl2 solvent at wavelength λ > 290 nm. The rate of polymerization increases with the increase in initiator concentration and reaction time. The results demonstrate that DMPDA acts as an efficient photoinitiator (AFA) without use of radical source in free radical accelerated cationic polymerization.  相似文献   

15.
The curing and adhesive properties of one‐component epoxy resins containing Epikote 828 and diimines, derived from N,N′‐di(1‐ethylpropylidene)‐m‐xylylenediamine, N,N′‐di(1‐ethylpropylidene)‐1,3‐diaminomethylcyclohexane (2), and N,N′‐di(1,3‐dimethylbutylidene)‐m‐xylylenediamine, which were used as water‐initiated hardeners, were examined. Diethyl ketone‐based imines with a lower electron density on the C?N carbon were efficiently hydrolyzed and showed curing activity. 2, a novel diethyl ketone‐based diimine, served as an efficient latent hardener of the epoxy resin. A paste of the epoxy resin with 2 showed good storage stability at room temperature and good adhesive properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 878–882, 2003  相似文献   

16.
Stable concentrated emulsions of methyl methacrylate/butyl acrylate were prepared with sodium dodecyl sulfate and cetyl alcohol as the compound surfactant and poly(vinyl alcohol) as the major reinforcer of the liquid film. With a redox system based on benzoyl peroxide/N,N′‐dimethyl phenylamine introduced into the concentrated emulsions, polymer particles with different shapes and sizes were obtained by initiation of the polymerization at low temperatures. We investigated the kinetic behaviors of concentrated emulsion polymerization and drew linear regression diagrams of its time–conversion curves in a constant rate phase (conversions ranged from 20 to 70%), and the experimental results show that the variation of the concentrations of the compound surfactant and initiator, the categories of reinforcers of the liquid film, the temperatures, and so on were responsible for the polymerization stability and the polymerization rate. Finally, the kinetics equation and activation energy of the initiator were obtained. The particle size and distribution of particle diameters of latex particles were determined by photon correlation spectroscopy. The determination results reveal that concentrations of the compound surfactant, polymerization temperatures, and so on affected the shape and size of the polymer particles greatly. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1695–1701, 2005  相似文献   

17.
Iron(II) chloride coordinated by succinic acid was first used as the catalyst in 2‐chloropropionitrile‐initiated atom transfer radical polymerization (ATRP) of acrylonitrile. N,N‐dimethylformamide was used as a solvent to improve the solubility of the ligand. An iron(II) chloride to succinic acid ratio of 0.5 not only gives the best control of molecular weight and its distribution but also provides rather rapid reaction rate. Effects of solvent on polymerization of acrylonitrile were also investigated. The induction period is shorter in N,N‐dimethylformamide than in propylene carbonate and toluene and the rate of the polymerization in N,N‐dimethylformamide is fastest. The molecular weight of polyacrylonitrile agrees reasonably well with the theoretical molecular weight of N,N‐dimethylformamide. The rate of polymerization increases and the induction period becomes shorter with increasing polymerization temperature, and the apparent activation energy was calculated to be 56.5 kJ mol?1. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1050–1054, 2006  相似文献   

18.
A new kind of polysiloxane containing N,N′-bis(diphenylsilyl)tetraphenylcyclodisilazane was prepared by the anionic polymerization with a “seed solution” as initiator. The synthesis of monomers N,N′-bis(hydroxydiphenylsilyl)tetraphenylcyclodisilazane (BHPTPC), N,N′-bis(chlorodiphenylsilyl)tetraphenylcyclodisilazane (BCPTPC), and 1,3-dichloro-1,1,3,3-tetraphenyldisilazane (DCTPS) are all reported in this study. The synthesized polysiloxane containing N,N′-bis(diphenylsilyl)tetraphenylcyclodisilazane was characterized by 1H–NMR, 29Si–NMR, gel permeation chromatography (GPC), and intrinsic viscosity. The thermal stability of the polysiloxane was studied by isothermal gravimetric analysis (IGA). The results demonstrated that the synthesized polysiloxane containing N,N′-bis(diphenylsilyl)tetraphenylcyclodisilazane had excellent thermal stability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 929–933, 2001  相似文献   

19.
Atom transfer radical polymerization has been a very useful method in the recent advances in controlled radical polymerization. It needs an activated alkyl halide as an initiator and a copper halide as a catalyst. This investigation reports the successful application of copper thiocyanate, a catalyst with a pseudohalide anion, in the presence of different ligands such as N,N,N=,N,N?,N?‐hexamethyltriethylenetetramine (HMTETA), pentyl‐2‐pyridylmethaneimine, and substituted bipyridine in the atom transfer radical polymerization of styrene. Among the three ligands used, HMTETA was found to be very efficient. The polymers were characterized with 13C‐NMR, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, and gel permeation chromatography analysis. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1418–1426, 2005  相似文献   

20.
Polymerization of isoprene (IP) with alkyllithium (RLi) catalysts in the presence of amines such as triethylamine (TEA), 1,2-dipiperidinoethane (DPPE) and N,N,N′,N′-tetramethyldiaminoalkanes [(CH3)2N(CH2)nN(CH3)2 where n=1, 2, 3, 4 and 6 (TMDAA)] has been studied. By adding the amines, the polymerization rate of IP was accelerated, and the contents of 3,4- and 1,2-units in the resulting polymers increased. The effects of methylene chain length of the TMDAA on the polymerization were examined. It was found that both the polymerization rates and the microstructure of the polymers depend on the methylene length of the TMDAA. The amines having 2 and 3 methylenes in (CH3)2N(CH2)nN(CH3)2 favoured production of the polymer consisting of predominantly 1,2- and 3,4-units. It was proposed that two types of active sites for the polymerization of IP were produced depending on the number n of the TMDAA. Two types of active species were confirmed to be produced with sec-BuLi in the presence of N,N,N′,N′-tetramethylethylenediamine (TMEDA) depending on the TMEDA/sec-BuLi mole ratios. © 1998 SCI.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号