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1.
The radical copolymerization of vinylidene fluoride (VDF) and 1‐bromo‐2,2‐difluoroethylene (BDFE) in 1,1,1,3,3‐pentafluorobutane solution at different monomer molar ratios (ranging from 96/4 to 25/75 mol %) and initiated by tert‐butylperoxypivalate (TBPPI, mainly) is presented. Poly(VDF‐co‐BDFE) copolymers of various aspects (from white powders to yellow viscous liquids) were produced depending on the copolymer compositions. The microstructures of the obtained copolymers were characterized by 19F and 1H NMR spectroscopy and by elementary analysis and these techniques enabled one to assess the contents of both comonomers in the produced copolymers. VDF was shown to be more incorporated in the copolymer than BDFE. From the extended Kelen and Tudos method, the kinetics of the radical copolymerization led to the determination of the reactivity ratios, ri, of both comonomers (rVDF = 1.20 ± 0.50 and rBDFE = 0.40 ± 0.15 at 75 °C) showing that VDF is more reactive than BDFE. Alfrey‐Price's Q and e values of BDFE monomer were calculated to be 0.009 (from QVDF = 0.008) or 0.019 (from QVDF = 0.015) and +1.22 (vs. eVDF = 0.40) or +1.37 (vs. eVDF = 0.50), respectively, indicating that BDFE is an electron‐accepting monomer. Statistic cooligomers were produced with molar masses ranging from 1,800 to 5,500 g/mol (assessed by GPC with polystyrene standards). A further evidence of the successful copolymerization was shown by the selective reduction of bromine atoms in poly(VDF‐co‐BDFE) cooligomers that led to analog PVDF. The thermal properties of the poly(VDF‐co‐BDFE) cooligomers were also determined and those containing a high VDF amount exhibited a high thermal stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3964–3976, 2010.  相似文献   

2.
The synthesis of fluorinated monomers bearing an ω‐trialkoxysilane function (4,5,5‐trifluoropent‐4‐ene‐1‐trimethoxysilane and 4,5,5‐trifluoropent‐4‐ene‐1‐triethoxysilane), their radical copolymerization with vinylidene fluoride (VDF), and the crosslinking of resulting copolymers are presented. The silicon‐containing fluoromonomers were prepared from a three step‐reaction from ClCF2CFClI, last step being the hydrosilylation of 1,1,2‐trifluoro‐1,4‐pentadiene with trialkoxysilane. The copolymerizations of these silicon‐containing fluoromonomers with VDF led to original PVDF bearing pendant trialkoxysilane functions. Their microstructures, characterized by NMR showed that VDF was the more incorporated. These latter ones were crosslinked in the presence of moisture at 200 °C leading to insoluble materials stable in solvents, oils, water, and to acids. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3896–3910, 2006  相似文献   

3.
An improved synthesis of 2,3,3‐trifluoroprop‐2‐enol (FA1) and its copolymerization in solution with vinylidene fluoride (VDF, or 1,1‐difluoroethylene) initiated by tert‐butyl peroxypivalate are presented. A new synthesis of FA1, with NaH and lithium diisopropylamine as bases, from 2,2,3,3‐tetrafluoropropanol is described. A series of nine copolymerization reactions were investigated from initial [VDF]0/[FA1]0 molar ratios of 9.1/90.9 to 94.2/5.8. The copolymer compositions were calculated via 19F NMR spectroscopy. From the Tidwell–Mortimer method, the reactivity ratios of both comonomers were determined (rFA1 = 0.11 ± 0.22 and rVDF = 0.83 ± 0.77 at 50°C), and they showed an azeotropic point. Alfrey and Price's Q and e values of FA1 were calculated to be 0.0178 (from QVDF = 0.008), 0.039 (from QVDF = 0.015), and 0.275 (from QVDF = 0.036) and 2.74 (vs eVDF = 1.20), 2.04 (vs eVDF = 0.50), and 1.94 (vs eVDF = 0.4), respectively, and they indicated that FA1 is an electron‐accepting monomer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3634–3643, 2002  相似文献   

4.
The radical co‐ and terpolymerization of perfluoro(4‐methyl‐3,6‐dioxaoct‐7‐ene) sulfonyl fluoride (PFSVE) with 1,1‐difluoroethylene (or vinylidene fluoride, VDF or VF2), hexafluoropropene (HFP), chlorotrifluoroethylene (CTFE), and bromotrifluoroethylene (BrTFE) is presented. Although PFSVE could not homopolymerize under radical initiation, it could be copolymerized in solution under a radical initiator with VDF, while its copolymerizations with HFP or CTFE led to oligomers in low yields. The terpolymerizations of PFSVE with VDF and HFP, with VDF and CTFE, or with VDF and BrTFE also led to original fluorinated terpolymers bearing sulfonyl fluoride side‐groups. The conditions of co‐ and terpolymerization were optimized in terms of the nature and the amount of the radical initiators, of the nature of solvents (fluorinated or nonhalogenated), and of the initial amounts of fluorinated comonomers. The different mol % contents of comonomers in the co‐ and terpolymers were assessed by 19F NMR spectroscopy. A wide range of co‐ and terpolymers containing mol % of PFSVE functional monomer ranging from 10 to 70% was produced. The kinetics of copolymerization of VDF with PFSVE enabled to assess the reactivity ratios of both comonomers: rVDF = 0.57 ± 0.15 and rPFSVE = 0.07 ± 0.04 at 120 °C. The thermal and physicochemical properties were also studied. Moreover, the glass transition temperatures (Tgs) of poly(VDF‐co‐PFSVE) copolymers containing different amounts of VDF and PFSVE were determined and the theoretical Tg of poly(PFSVE) homopolymer was deduced. Then, the hydrolysis of the ? SO2F into ? SO3H function was investigated and enabled the synthesis of fluorinated copolymers bearing sulfonic acid functions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1814–1834, 2007  相似文献   

5.
The radical copolymerization in solution of vinylidene fluoride (VDF; or 1,1‐difluoroethylene) with methyl 1,1‐dihydro‐4,7‐dioxaperfluoro‐5,8‐dimethyl non‐1‐enoate (MDP) initiated by di‐tert‐butyl peroxide is presented. Six copolymerization reactions were investigated with initial [VDF]0/[MDP]0 molar ratios of 35/65 to 80/20. Both of these comonomers copolymerized in this range of copolymerization. Moreover, these comonomers homopolymerized separately under these conditions. The copolymer compositions of these random copolymers were calculated by means of 19F NMR spectroscopy, which allowed the quantification of the respective amounts of each monomeric unit in the copolymers. The Tidwell–Mortimer method was used for the assessment of the reactivity ratios (ri) of both comonomers, which showed a higher incorporation of MDP in the copolymers (rMDP = 2.41 ± 2.28 and rVDF = 0.38 ± 0.21 at 120 °C). The Alfrey–Price Q and e values of the trifluoroallyl monomer MDP were calculated to be 0.024 (from QVDF = 0.008) or 0.046 (from QVDF = 0.015) and 0.70 (vs eVDF = 0.40) or 0.80 (vs eVDF = 0.50), respectively, indicating that MDP was an electron‐accepting monomer. The thermal properties of these fluorinated copolymers were also determined. Except for those containing a high amount of VDF, the copolymers were amorphous. Each showed one glass‐transition temperature (Tg) only, and with known laws of Tg's, Tg of the MDP homopolymer was assessed. It was compared to that obtained from the direct radical homopolymerization of MDP and discussed. Indeed, these two values were close (Tg = ?3 °C). Thermogravimetric analyses were performed, and they showed that the copolymers were rather thermostable because the thermal degradation occurred at 280 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3109–3121, 2003  相似文献   

6.
The radical terpolymerization of 8‐bromo‐1H,1H,2H‐perfluorooct‐1‐ene with vinylidene fluoride (VDF) and perfluoro(4‐methyl‐3,6‐dioxaoct‐7‐ene) sulfonyl fluoride is presented. Changing the feed compositions of these three fluorinated comonomers enabled us to obtain different random‐type poly[vinylidene fluoride‐ter‐perfluoro(4‐methyl‐3,6‐dioxaoct‐7‐ene) sulfonyl fluoride‐ter‐8‐bromo‐1H,1H,2H‐perfluorooct‐1‐ene] terpolymers containing various sulfonyl fluoride and brominated side groups. Yields higher than 70% were reached in all cases. The hydrolysis of the sulfonyl fluoride group into the ? SO3Li function in the presence of lithium carbonate was quantitatively achieved without the content of VDF being affected, and so dehydrofluorination of the VDF base unit was avoided. These original terpolymers were then crosslinked via dangling bromine atoms in the presence of a peroxide/triallyl isocyanurate system, which produced films insoluble in organic solvents such as acetone and dimethylformamide (which totally dissolved uncured terpolymers). The acidification of ? SO3Li into the ? SO3H function enabled protonic membranes to be obtained. The thermal stabilities of the crosslinked materials were higher than those of the uncured terpolymers, and their electrochemical performances were investigated. According to the contents of the sulfonic acid side functions, the ion‐exchange capacities ranged from 0.6 to 1.5 mequiv of H+/g, whereas the water uptake and conductivities ranged from 5–26% (±11%) and from 0.5 to 6.0 mS/cm, respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4566–4578, 2006  相似文献   

7.
The radical co‐ and terpolymerization of 4‐[(α,β,β‐trifluorovinyl)oxy]bromo benzene (TFVOBB) with 1,1‐difluoroethylene (or vinylidene fluoride, VDF, or VF2), hexafluoropropene (HFP), perfluoromethyl vinyl ether (PMVE), and chlorotrifluroroethylene (CTFE) is presented. Although TFVOBB could be thermocyclodimerized, it could not homopolymerize under radical initiation. TFVOBB could be copolymerized in solution under a radical initiator with VDF or CTFE comonomers, while its copolymerization with HFP or PMVE were unsuccessful. The terpolymerization of TFVOBB with VDF and HFP, or VDF and PMVE, or VDF and CTFE also led to original fluorinated terpolymers bearing bromoaromatic side‐groups. The conditions of co‐ and terpolymerization were optimized in terms of the nature of the radical initiators, and of the nature of solvents (fluorinated or nonhalogenated). Various monomer concentrations in the co‐ and terpolymers were assessed by 19F and 1H‐NMR spectroscopy. The thermal and physico chemical properties were also studied. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5077–5097, 2004  相似文献   

8.
The radical copolymerization of maleimide (MI) and ethyl α‐propylacrylate was performed using 1,1,2,2‐tetraphenyl‐1,2‐bis(trimethylsilyloxy) ethane (TPSE) as initiator. The whole copolymerization process might be divided into two stages: in the first stage, the copolymerization was carried out on the common radical mechanism, the molecular weight of the copolymer increased rapidly in much lower conversion (< 85%), and did not depend on the polymerization time and conversion; in the second stage, molecular weight of the copolymer increased linearly with the conversion and the polymerization time. It was found, however, when the conversion was higher than a certain value, for example, more than 36%, the molecular weight of the copolymer was nearly unchangeable with the polymerization time and the molecular weight distribution was widened. The effect of reaction conditions on copolymerization was discussed and the reactivity ratios were calculated by the Kelen–Tudos method, the values were rMI = 0.13 ± 0.03, rEPA = 0.58 ± 0.06 for TPSE system and rMI = 0.12 ± 0.03, rEPA = 0.52 ± 0.06 for AIBN system. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2872–2878, 2000  相似文献   

9.
The synthesis of poly(VDF‐co‐TFMA) copolymers (where VDF and TFMA stand for vinylidene fluoride and α‐trifluoromethacrylic acid, respectively) by iodine transfer polymerization without any surfactant is presented. First, the synthesis and the control of the copolymerization of VDF and TFMA were investigated in the presence of two chain transfer agents, 1‐perfluorohexyl iodide (C6F13I) and 1,4‐diodoperfluorobutane (IC4F8I). TFMA monomer was incorporated in the copolymer in good yields. Moreover, the molecular weights of the resulting poly(VDF‐co‐TFMA) copolymers were in good agreement with the theoretical values for feed of TFMA/VDF ratios that ranged from 50/50 to 0/100 mol %, showing that TFMA does not disturb the controlled radical polymerization of VDF. The microstructures of the produced copolymers were characterized by 1H and 19F NMR to assess the amount of each comonomer, and the molecular weights and the end‐groups of the copolymers. The results on the control of the copolymerization were compared to those obtained with and without the presences of TFMA and surfactant. The addition of a low amount of TFMA improved the control of the polymerization of VDF without using any surfactant. Also, the size of particles, assessed by light scattering, was smaller than 200 nm. The addition of TFMA in low proportions, that is, 5 to 10 mol %, enabled us to stabilize the particle size and to decrease the size by one order of magnitude. The emulsifying behavior of TFMA (in low amount in the copolymer, that is, <10 mol %) was similar to those achieved when a surfactant was added. Indeed, neither sedimentation nor destabilization was observed after several days. The reactivity ratios for rTFMA and rVDF were 0 and 1.6 at 80 °C, respectively. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4710–4722, 2009  相似文献   

10.
Ethylene/1‐hexene copolymerizations with disiloxane‐bridged metallocenes, rac‐ and meso‐1,1,3,3‐tetramethyldisiloxanediyl‐bis(1‐indenyl)zirconium dichloride (rac‐ 1 , meso‐ 1 ) activated by modified methylaluminoxane were performed to investigate the influence of conformational dynamics on comonomer selectivity. Although 1H NOESY (nuclear Overhauser and exchange spectroscopy) analysis indicated that the most stable conformation for the meso isomer in solution was that in which both indenes project over the metal coordination site, this isomer showed higher 1‐hexene selectivity in copolymerization (re = 140 ± 30, rh = 0.024 ± 0.004) than the rac isomer with only one indene over the coordination site (re = 240 ± 20, rh = 0.005 ± 0.001). The meso isomer showed high 1‐hexene selectivity, a high product of reactivity ratios (rerh = 3.3 ± 0.5) and produced copolymers that could be separated into fractions with different ethylene content suggesting that the active species exhibited multisite behavior and populated conformations with different comonomer selectivities during the copolymerization. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3323–3331, 2004  相似文献   

11.
The synthesis of original cotelomers based on 3,3,3‐trifluoropropene (TFP) and vinylidene fluoride (VDF) with a general formula: RF‐[CH2? CF2]n? [CH2? CH(CF3)]m? I (where n = 1–63, m = 2–640, and RF = (CF3)2CF) was achieved by sequential and random cotelomerizations in the presence of RFI. The radical cotelomerizations were initiated by thermal decomposition of different peroxide and persulfate initiators either in bulk, in solution (in the presence of acetonitrile or 1,1,1,3,3‐pentafluorobutane as the solvents), and in aqueous process (emulsion). Different adducts were obtained in good yield (50–70 wt %) with a relative proportion of each adduct depending on (i) the R0 = [RFI]0/([TFP]0+[VDF]0) initial molar ratio, (ii) the reaction temperature, and (iii) C0 = [In]0/([TFP]0+[VDF]0). Random cotelomerization gave higher yields than those obtained from the sequential cotelomerization. When the concentration of the chain transfer agent increased, the molecular weights of the resulting poly(VDF‐co‐TFP) cotelomers decreased and showed that the R0 ratio targeted the molecular weights (~700–66,000 g mol?1). Some of the obtained molecular weights were exceptionally high for a (co)telomerization. The kinetics of the radical cotelomerization of VDF and TFP led to the determination of the reactivity ratios of both comonomers (rVDF = 0.28 ± 0.07 and rTFP = 2.35 ± 0.26 at 75 °C). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3964–3981, 2009  相似文献   

12.
The new monomer N′‐(β‐methacryloyloxyethyl)‐2‐pyrimidyl‐(p‐benzyloxy‐ carbonyl)aminobenzenesulfonamide (MPBAS) (M1) is synthesized using sulfadiazine as parent compound. It could be homopolymerized and copolymerized with N‐phenyl maleimide (NPMI) (M2) by radical mechanism using AIBN as initiator at 60 °C in dimethylformamide. The new monomer MPBAS and polymers were identified by IR, element analysis and 1H NMR in detail. The monomer reactivity ratios in copolymerization were determined by YBR method, and r1 (MPBAS) = 2.39 ± 0.05, r2 (NPMI) = 0.33 ± 0.02. In the presence of ammonium formate, benzyloxycarbonyl groups could be broken fluently from MPBAS segments of copolymer by catalytic transfer hydrogenation, and the copolymer with sulfadiazine side groups are recovered. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2548–2554, 2000  相似文献   

13.
The controlled nitroxide‐mediated homopolymerization of 9‐(4‐vinylbenzyl)‐9H‐carbazole (VBK) and the copolymerization of methyl methacrylate (MMA) with varying amounts of VBK were accomplished by using 10 mol % {tert‐butyl[1‐(diethoxyphosphoryl)‐2,2‐dimethylpropyl]amino} nitroxide relative to 2‐({tert‐butyl[1‐(diethoxyphosphoryl)‐2,2‐dimethylpropyl]amino}oxy)‐2‐methylpropionic acid (BlocBuilder?) in dimethylformamide at temperatures from 80 to 125 °C. As little as 1 mol % of VBK in the feed was required to obtain a controlled copolymerization of an MMA/VBK mixture, resulting in a linear increase in molecular weight versus conversion with a narrow molecular weight distribution (Mw /Mn ≈ 1.3). Preferential incorporation of VBK into the copolymer was indicated by the MMA/VBK reactivity ratios determined: rVBK = 2.7 ± 1.5 and rMMA = 0.24 ± 0.14. The copolymers were found significantly “living” by performing subsequent chain extensions with a fresh batch of VBK and by 31P NMR spectroscopy analysis. VBK was found to be an effective controlling comonomer for NMP of MMA, and such low levels of VBK comonomer ensured transparency in the final copolymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011  相似文献   

14.
The bulk radical copolymerization of tetrafluoroethylene (TFE) with 4,5,5‐trifluoro‐4‐ene pentyl acetate (FAc), initiated by tert‐butyl peroxypivalate to synthesize original, functionalized fluorinated poly(TFE‐co‐FAc), was investigated. FAc monomer was prepared from a five‐step process. The copolymerization was carried out in batch at different initial monomer molar ratios ([TFE]o/[FAc]o ranging from 95/5 to 10/90 mol %) and at different initiator concentrations (ranging between 0.075 and 1.100 mol % about the monomers) at 70 °C. All the experiments revealed the production of fluorooligomers as evidenced by an allylic‐transfer reaction from FAc. The microstructure of these copolymers (i.e., the molar percentage of both monomers in the copolymers) was assessed by 19F NMR spectroscopy. From the kinetics of copolymerization, two key characteristics were determined. First, the reaction order to the initiator (being 1.07) and that of FAc monomer (0.85) showed a heterogeneous character of the copolymerization and monomolecular chain‐transfer reaction to FAc. Second, from the Tidwell and Mortimer method, the reactivity ratios of both comonomers were determined, showing a tendency to alternance in a wide range of initial monomeric ratios (30/70–70/30): rFAc = 0.20 ± 0.26 and rTFE = 0.18 ± 0.15. Alfrey and Price's Q and e values of FAc were calculated by Greenley's technique [QFAc = 0.098 (from QTFE = 0.032) and eFAc = 1.23 (vs eTFE = 1.63)], indicating that FAc is a strong electron‐withdrawing monomer as TFE. The normalized monomer‐diad and triad fractions as a function of the polymer composition were obtained from the comonomer sequence‐distribution procedure. The average molecular weights and molecular weight distributions as well as the thermal properties (glass‐transition temperature and decomposition temperature) of the fluorocopolymers were assessed and are discussed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1693–1706, 2004  相似文献   

15.
The free‐radical homopolymerization and copolymerization behavior of N‐(2‐methylene‐3‐butenoyl)piperidine was investigated. When the monomer was heated in bulk at 60 °C for 25 h without an initiator, about 30% of the monomer was consumed by the thermal polymerization and the Diels–Alder reaction. No such side reaction was observed when the polymerization was carried out in a benzene solution with 1 mol % 2,2′‐azobisisobutylonitrile (AIBN) as an initiator. The polymerization rate equation was found to be Rp ∝ [AIBN]0.507[M]1.04, and the overall activation energy of polymerization was calculated to be 89.5 kJ/mol. The microstructure of the resulting polymer was exclusively a 1,4‐structure that included both 1,4‐E and 1,4‐Z configurations. The copolymerizations of this monomer with styrene and/or chloroprene as comonomers were carried out in benzene solutions at 60 °C with AIBN as an initiator. In the copolymerization with styrene, the monomer reactivity ratios were r1 = 6.10 and r2 = 0.03, and the Q and e values were calculated to be 10.8 and 0.45, respectively. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1545–1552, 2003  相似文献   

16.
New functional monomer methacryloyl isocyanate containing 4‐chloro‐1‐phenol (CPHMAI) was prepared on reaction of methacryloyl isocyanate (MAI) with 4‐chloro‐1‐phenol (CPH) at low temperature and was characterized with IR, 1H, and 13C‐NMR spectra. Radical polymerization of CPHMAI was studied in terms of the rate of polymerization, solvent effect, copolymerization, and thermal properties. The rate of polymerization of CPHMAI has been found to be smaller than that of styrene under the same conditions. Polar solvents such as dimethylsulfoxide (DMSO) and N,N‐dimethyl formamide (DMF) were found to slow the polymerization. Copolymerization of CPHMAI (M1) with styrene (M2) in tetrahydrofuran (THF) was studied at 60°C. The monomer reactivity ratio was calculated to be r1 = 0.49 and r2 = 0.66 according to the method of Fineman—Ross. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 469–473, 2000  相似文献   

17.
The synthesis of [1‐(fluoromethyl)vinyl]benzene (or α‐(fluoromethyl)styrene, FMB) and its radical copolymerization with chlorotrifluorethylene (CTFE), initiated by tert‐butyl peroxypivalate (TBPPi) are presented. The allyl monomer [H2C = C(CH2F)C6H5] was obtained by electrophilic fluorodesilylation of trimethyl(2‐phenylprop‐2‐en‐1‐yl)silane in 93% yield. A series of seven copolymerization reactions were carried out starting from initial [CTFE]0/([FMB]0 + [CTFE]0) molar ratios ranging from 19.6 to 90.0 mol %. The molar compositions of the obtained poly(CTFE‐co‐FMB) copolymers were assessed by means of 19F nuclear magnetic resonance spectroscopy. Statistic copolymers were produced with molar masses ranging between 13,800 and 25,600 g/mol. From the Kelen and Tudos method, the kinetics of the copolymerization led to the determination of the reactivity ratios, ri, of both comonomers (rCTFE = 0.4 ± 0.2 and rFMB = 3.7 ± 1.8 at 74 °C) showing that FMB is more reactive than CTFE as well as other halogenated or nonhalogenated monomers involved in the radical copolymerization with CTFE. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3843–3850, 2007  相似文献   

18.
Perfluorotetrahydro‐2‐methylene‐furo[3,4‐d][1,3]dioxole (monomer I ) and perfluoro‐2‐methylene‐4‐methoxymethyl‐1,3‐dioxolane (monomer II ) are soluble in perfluorinated or partially fluorinated solvents and readily polymerize in solution or in bulk when initiated by a free‐radical initiator, perfluorodibenzoyl peroxide. The copolymerization parameters have been determined with in situ 19F NMR measurements. The copolymerization reactivity ratios are r I = 1.80 and r II = 0.80 in 1,1,2‐trichlorotrifluoroethane at 41 °C and r I = 0.97 and r II = 0.85 for the bulk polymerization. These data show that this copolymerization pair has a good copolymerization tendency and yields nearly ideal random copolymers. The copolymers have only one glass‐transition temperature from 101 to 168 °C, depending on the copolymer compositions. Melting endotherms have not been observed in their differential scanning calorimetry traces, and this indicates that all the copolymers with different compositions are completely amorphous. These copolymers are thermally stable (the initial decomposition temperatures are higher than 350 °C under an N2 atmosphere) and have low refractive indices and high optical transparency from UV to near‐infrared. Copolymer films prepared by casting were flexible and tough. These properties make the copolymers ideal candidates as optical and electrical materials. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1613–1618, 2006  相似文献   

19.
Free‐radical homo‐ and copolymerization behavior of N,N‐diethyl‐2‐methylene‐3‐butenamide (DEA) was investigated. When the monomer was heated in bulk at 60 °C for 25 h without initiator, rubbery, solid gel was formed by the thermal polymerization. No such reaction was observed when the polymerization was carried out in 2 mol/L of benzene solution with with 1 mol % of azobisisobutyronitrile (AIBN) as an initiator. The polymerization rate (Rp) equation was Rp ∝ [DEA]1.1[AIBN]0.51, and the overall activation energy of polymerization was calculated 84.1 kJ/mol. The microstructure of the resulting polymer was exclusively a 1,4‐structure where both 1,4‐E and 1,4‐Z structures were included. From the product analysis of the telomerization with tert‐butylmercaptan as a telogen, the modes of monomer addition were estimated to be both 1,4‐ and 4,1‐addition. The copolymerizations of this monomer with styrene and/or chloroprene as comonomers were also carried out in benzene solution at 60 °C. In the copolymerization with styrene, the monomer reactivity ratios obtained were r1 = 5.83 and r2 = 0.05, and the Q and e values were Q = 8.4 and e = 0.33, respectively. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 999–1007, 2004  相似文献   

20.
The radical copolymerization of chlorotrifluoroethylene (CTFE) with 3,3,4,4‐tetrafluoro‐4‐bromobut‐1‐ene (BTFB) initiated by tert‐butylperoxypivalate is presented. The microstructures of the obtained copolymers are determined by means of NMR spectroscopies and elemental analysis and show that random copolymers were obtained. A wide range of poly(CTFE‐co‐BTFB) copolymers is synthesized, containing from 17 to 89 mol % of CTFE. In all the cases, CTFE is the less reactive of both comonomers. Td10% values, ranging from 163 up to 359 °C, are dependent on the BTFB content. These variations of thermal property are attributed to the increase in the number of C‐H and C‐Br bonds breakdown when the BTFB molar percentage in the copolymer is higher. Tg values range from 19 to 39 °C and a decreasing trend is observed when increasing the amount of BTFB in the copolymer. This observation arises from the higher flexibility of the copolymer when increasing the number of fluorobrominated lateral chains. These original fluoropolymers bearing reactive pendant bromo groups are suitable candidates for various applications. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1714–1720  相似文献   

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