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1.
The hyperbranched copolymers were obtained by the atom transfer radical copolymerization of p‐(chloromethyl)styrene (CMS) with N‐cyclohexylmaleimide (NCMI) catalyzed by CuCl/2,2′‐bipyridine (bpy) in cyclohexanone (C6H10O) or anisole (PhOCH3) with CMS as the inimer. The influences of several factors, such as temperature, solvent, the concentration of CuCl and bpy, and monomer ratio, on the copolymerization were subsequently investigated. The apparent enthalpy of activation for the overall copolymerization was measured to be 37.2 kJ/mol. The fractional orders obtained in the copolymerization were approximately 0.843 and 0.447 for [CuCl]0 and [bpy]0, respectively. The monomer reactivity ratios were evaluated to be rNCMI = 0.107 and rCMS = 0.136. The glass transition temperature of the resultant hyperbranched copolymer increases with increasing fNCMI, which indicates that the heat resistance of the copolymer has been improved by increasing NCMI. The prepared hyperbranched CMS/NCMI copolymers were used as macroinitiators for the solution polymerization of styrene to yield star‐shaped poly(CMS‐co‐NCMI)/polystyrene block copolymers by atom transfer radical polymerization. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1992–1997, 2000  相似文献   

2.
The kinetics for the radical copolymerization of methyl methacrylate (MMA) with N‐cyclohexylmaleimide (NCMI) was investigated. The initial copolymerization rate Rp is proportional to the initiator concentration to the power of 0.54. The apparent activation energy of the overall copolymerization was measured to be 69.0 kJ/mol. The monomer reactivity ratios were determined to be rNCMI = 0.42 and rMMA = 1.63. Rp reduces slightly, and the molecular weight of the resultant copolymer decreases with increasing the concentration of the chain transfer agent N‐dodecanethiol (RSH). The more the transfer agent, the narrower the molecular weight distribution of the resulting copolymer. The following chain‐transfer constant of RSH for the copolymerization of MMA with NCMI in benzene at 50°C was obtained: Cs = 0.23. The glass transition temperature (Tg) of the copolymer increases with increasing fNCMI, which indicates that adding NCMI can improve the heat resistance of Plexiglas. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1293–1297, 1999  相似文献   

3.
N‐dodecanethiol (RSH) was found efficient to initiate the radical copolymerization of methyl methacrylate (MMA) with N‐cyclohexylmaleimide (NCMI) at 40–60°C. The initial copolymerization rate, Rp, increases respectively with increasing [RSH] and the mol fraction of NCMI in the comonomer feed, fNCMI. The molecular weight of the copolymer decreases with increasing [RSH]. The initiator transfer constant of RSH was determined to be CI = 0.21. The apparent activation energy of the overall copolymerization was measured to be 46.9 kJ/mol. The monomer reactivity ratios were determined to be rNCMI = 0.32 and rMMA = 1.35. The glass transition temperature of the copolymer increases obviously with increasing fNCMI, which indicates that adding NCMI may improve the heat resistance of plexiglass. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1417–1423, 1999  相似文献   

4.
The γ-ray-induced copolymerization of vinylphosphonic dichloride (VPDC) with methyl methacrylate (MMA) and styrene (St) was studied at 25°C (liquid phase) and ?78°C (Solid phase). The reaction mechanisms are discussed. The reactivity ratios for the copolymerization of the VPDC–MMA system were determined as follows: The difference between the reactivity between the liquid-phase (25°C) and solid-phase (?78°C) copolymerization is mainly attributable to the r2 value. The behavior of the liquid-phase copolymerization of the VPDC–St system was anomalous, the r1 value being negative in the range from 0 to 80 mole-% of VPDC monomer. In the solid-phase (?78°C) copolymerization for the VPDC–St system, the reactivity ratios r1 and r2 were 0.097 and 1.6, respectively. The rate of copolymerization (Rp) at 25°C, for both the VPDC–MMA and VPDC–St systems, passes a maximum point at a certain monomer concentration, suggesting that the composition of copolymer is considerably affected by Rp. This phenomenon was interpreted by the assumption that an energy transfer reaction from VPDC monomer to the other vinyl compound can easily occur.  相似文献   

5.
Glycidyl methacrylate (GMA) and methyl methacrylate (MMA) copolymers were synthesized by atom transfer radical polymerization (ATRP). The effect of different molar fractions of GMA, ranging from 0.28 to 1.0, on the polymer polydispersity index (weight‐average molecular weight/number‐average molecular weight) as the indicator of a controlled process was investigated at 70°C, with ethyl 2‐bromoisobutyrate as an initiator and 4,4′‐dinonyl‐2,2′‐bipyridyne (dNbpy)/CuBr as a catalyst system in anisole. The monomer reactivity ratios (r values) were obtained by the application of the conventional linearization Fineman–Ross method (rGMA = 1.24 ± 0.02 and rMMA = 0.85 ± 0.03) and by the Mayo–Lewis method (rGMA = 1.19 ± 0.04 and rMMA = 0.86 ± 0.03). The molecular weights and polydispersities of the copolymers exhibited a linear increase with GMA content. The copolymer compositions were determined by 1H‐NMR and showed a domination of syndiotactic structures. The glass‐transition temperatures (Tg) of the copolymers analyzed by differential scanning calorimetry (DSC) decreased in the range 105–65°C with increasing GMA units. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

6.
The dendritic Fréchet‐type polyarylether 2‐bromoisobutyrates (Gn‐Br, n = 1–3) as macroinitiators for the ‘living’/controlled radical polymerization of styrene (St) and methyl methacrylate (MMA) were investigated. The atom transfer radical polymerization of St and MMA carried out with CuBr/bpy (2,2′‐bipyridine) catalyst in bulk yielded well‐defined dendritic–linear diblock copolymers (Gn–PSt and Gn–PMMA). The use of G3–PSt for the block copolymerization of MMA and G3–PMMA for the chain extension polymerization of MMA in the presence of CuBr/bpy catalyst is also described. The triblock copolymers obtained were of predetermined molecular weights and relatively low polydispersities, which indicates the living nature of the reaction system. © 2002 Society of Chemical Industry  相似文献   

7.
A Lotus spreadsheet (LS) was utilized as part of a copolymerization study of methyl methacrylate (MMA) with N-phenylmaleimide (MP) and with some derivatives of MP, namely N-o-chlorophenylmaleimide (MOCP), N-p-tolylmaleimide (MPT), and N-o-tolylmaleimide (MOT). The use of LS provided a very rapid method to obtain values of copolymerization parameters which were in very good agreement with non-spreadsheet reported values. Further, a novel LS macro was developed which could be employed to ascertain the shape of the copolymer composition curve (copolymer composition as a function of monomer composition). Monomer reactivity ratios, r1 and r2, were determined as well as values of semi-empirical copolymerization parameters Q and e. An attempt was made to correlate the monomer structures used with the values of Q and e. An empirical decomposition temperature index (DTI) was also devised to measure the thermal stability of copolymers of MMA and MP as a function of MP content. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 891–900, 1997  相似文献   

8.
Summary Novel hyperbranched copolymers were successfully synthesized by the controlled charge transfer complex inimer and living radical copolymerization of p-(chloromethyl)styrene (PCMS) and acrylonitrile (AN). The resulting copolymers were characterized by SEC, NMR, FTIR, DSC and elemental analysis etc.. The influences of reaction conditions, such as the polymerization temperature, the catalyst (CuBr) concentration and the monomer ratio, on the resulting copolymers were investigated in detail. The monomer reactivity ratios were evaluated to be rPCMS=0.937 and rAN=0.088 respectively by the Fineman-Ross method. The higher are the polymerization temperature and the ratio of catalyst to monomer, the higher is the branching degree of the resulting copolymer. When the amount of monomer AN was used in excess than that of the monomer PCMS in the raw feed, the hyperbranched predominantly alternating copolymers HP[PCMS-co-AN] could be obtained. These hyperbranched copolymers were successfully used as functional macroinitiators to synthesize the star-shaped poly(PCMS-co-AN)/poly(MMA) block copolymers.  相似文献   

9.
A novel perfluorinated acrylic monomer 3,5‐bis(perfluorobenzyloxy)benzyl acrylate (FM) with perfluorinated aromatic units was synthesized with 3,5‐bis(perfluorobenzyl)oxybenzyl alcohol, acryloyl chloride, and triethylamine. Copolymers of FM monomer with methyl methacrylate (MMA) were prepared via free‐radical polymerization at 80°C in toluene with 2,2′‐azobisisobutyronitrile as the initiator. The obtained copolymers were characterized by 1H‐NMR and gel permeation chromatography. The monomer reactivity ratios for the monomer pair were calculated with the extended Kelen–Tüdos method. The reactivity ratios were found to be r1 = 0.38 for FM, r2 = 1.11 for MMA, and r1r2 < 1 for the pair FM–MMA. This shows that the system proceeded as random copolymerization. The thermal behavior of the copolymers was investigated by thermogravimetric analysis and differential scanning calorimetry (DSC). The copolymers had only one glass‐transition temperature, which changed from 46 to 78°C depending on the copolymer composition. Melting endotherms were not observed in the DSC traces; this indicated that all of the copolymers were completely amorphous. Copolymer films were prepared by spin coating, and contact angle measurements of water and ethylene glycol on the films indicated a high degree of hydrophobicity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

10.
Atom transfer radical polymerization (ATRP) is a promising method to synthesize well‐defined polymer/inorganic nanoparticles. However, the surface‐initiated ATRP from commercially mass produced inorganic nanoparticles has seldom been studied. In this study, the surface‐initiated ATRP of methylmethacrylate (MMA) from commercially mass produced fumed silica (SiO2) nanoparticles was investigated. Unlike the ATRP of MMA initiated from a free initiator, the controllability of ATRP of MMA from the surface of fumed silica nanoparticles was much better using ligand 2,2'‐bipyridine (bpy) than N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine (PMDETA) as the initiator was immobilized on the surface of the SiO2 nanoparticles and the presence of the SiO2 nanoparticles made the CuCl/bpy catalyst system a homogeneous catalyst system and CuCl/PMDETA a heterogeneous one. The appropriate molar ratio of monomer and initiator was essential for preparing controlled PMMA/SiO2 nanoparticles. The entire process of ATRP of MMA from the surface of SiO2 nanoparticles was controllable when using bpy as ligand, xylene as solvent and with a monomer to initiator ratio of 300:1. The 1H NMR results indicated that the PMMA on the surface of the SiO2 was prepared via ATRP initiated from 4‐(chloromethyl)phenyltrimethoxysilane. The well‐defined PMMA/SiO2 nanoparticles obtained have good thermal stability and are well dispersed in organic media as proved by TGA, dynamic light scattering and transmission electron microscopy. © 2013 Society of Chemical Industry  相似文献   

11.
Summary Free radical copolymerization of 4-phenylbut-1-en-3-yne (PB) with methyl methacrylate(MMA) was studied. The polymerization of MMA was inhibited by the presence of small amounts of PB, but the copolymerization yield increased with increase in the PB concentration, and PB-rich copolymers were obtained. The monomer reactivity ratios, rMMA and rPB, were found to be 0.096 and 2.83, respectively. The Q and e values of PB were calculated by using the values of MMA and were found to be 2.69 and 0.74, respectively. The slow polymerization and low molecular weights were attributed to the low propagating activity of PB radicals.  相似文献   

12.
Free radical copolymerization kinetics of 2‐(diisopropylamino)ethyl methacrylate (DPA) with styrene (ST) or methyl methacrylate (MMA) was investigated and the corresponding copolymers obtained were characterized. Polymerization was performed using tert‐butylperoxy‐2‐ethylhexanoate (0.01 mol dm?3) as initiator, isothermally (70 °C) to low conversions (<10 wt%) in a wide range of copolymer compositions (10 mol% steps). The reactivity ratios of the monomers were calculated using linear Kelen–Tüd?s (KT) and nonlinear Tidwell–Mortimer (TM) methods. The reactivity ratios for MMA/DPA were found to be r1 = 0.99 and r2 = 1.00 (KT), r1 = 0.99 and r2 = 1.03 (TM); for the ST/DPA system r1 = 2.74, r2 = 0.54 (KT) and r1 = 2.48, r2 = 0.49 (TM). It can be concluded that copolymerization of MMA with DPA is ideal while copolymerization of ST with DPA has a small but noticeable tendency for block copolymer building. The probabilities for formations of dyad and triad monomer sequences dependent on monomer compositions were calculated from the obtained reactivity ratios. The molar mass distribution, thermal stability and glass transition temperatures of synthesized copolymers were determined. Hydrophobicity of copolymers depending on the composition was determined using contact angle measurements, decreasing from hydrophobic polystyrene and poly(methyl methacrylate) to hydrophilic DPA. Copolymerization reactivity ratios are crucial for the control of copolymer structural properties and conversion heterogeneity that greatly influence the applications of copolymers as rheology modifiers of lubricating oils or in drug delivery systems. © 2015 Society of Chemical Industry  相似文献   

13.
The free radical copolymerization of methyl methacrylate (MMA) or styrene (St) with N-(4-carboxyphenyl)maleimide (CPMI) was carried with AIBN as an initiator in THF solvent at 80°C. A series of copolymers of MMA and St with CPMI were prepared using different feed ratios of comonomers. The values of monomer reactivity ratios (r1, r2) determined by Fineman-Ross and Kelen-Tudos methods are 0.26 and 2.51 in the CPMI/MMA system and 0.08 and 0.22 in the CPMI/St system. Alfrey–Price Q-e values for CPMI were calculated as Q = 1.05 and e = 0.41 in the CPMI/MMA system and Q = 1.21 and e = 0.91 in the CPMI/St system. The polymer samples have been characterized by solubility tests, intrinsic viscosity measurements, FT-IR and 1H-NMR spectral analysis, and thermo-gravimetric analysis. It was found that the initial and final decomposition temperatures increased with increasing the amount of CPMI in the copolymer. The integral procedural decomposition temperature and energy of activation of thermal degradation have also been reported.  相似文献   

14.
The atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) is often carried out under homogeneous conditions, so the residual metal catalyst in the polymer often influences the quality of the polymer and causes environmental pollution in the long run. Novel CuBr/4,4′‐bis(RfCH2OCH2)‐2,2′‐bpy complexes (Rf = n‐C9F19, n‐C10F21, or n‐C11F23; 2,2′‐bpy = 2,2′‐bipyridine) are insoluble in toluene at room temperature yet readily dissolve in toluene at elevated temperatures to form homogeneous phases for use as catalysts in the ATRP reaction, and the Cu complexes precipitate again upon cooling. The CuBr/4,4′‐bis(n‐C9F19CH2OCH2)‐2,2′‐bpy system produced the best results (e.g., polydispersity index by gel permeation chromatography = 1.26–1.41), in that the residual Cu content in the polymer was as low as 19.3 ppm when the ATRP of MMA was carried out in the thermomorphic mode. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

15.
The article describes the synthesis and characterization of N‐(4‐methoxy‐3‐chlorophenyl) itaconimide (MCPI) and N‐(2‐methoxy‐5‐chlorophenyl) itaconimide (OMCPI) obtained by reacting itaconic anhydride with 4‐methoxy‐3‐chloroanisidine and 2‐methoxy‐5‐chloroanisidine, respectively. Structural and thermal characterization of MCPI and OMCPI monomers was done by using 1H NMR, FTIR, and differential scanning calorimetry (DSC). Copolymerization of MCPI or OMCPI with methyl methacrylate (MMA) in solution was carried out at 60°C using AIBN as an initiator and THF as solvent. Feed compositions having varying mole fractions of MCPI and OMCPI ranging from 0.1 to 0.5 were taken to prepare copolymers. Copolymerizations were terminated at low percentage conversion. Structural characterization of copolymers was done by FTIR, 1H NMR, and elemental analysis and percent nitrogen content was used to calculate the copolymer composition. The monomer reactivity ratios for MMA–MCPI copolymers were found to be r1 (MMA) = 0.32 ± 0.03 and r2 (MCPI) = 1.54 ± 0.05 and that for MMA–OMCPI copolymers were r1 (MMA) = 0.15 ± 0.02 and r2 (OMCPI) = 1.23 ± 0.18. The intrinsic viscosity [η] of the copolymers decreased with increasing mole fraction of MCPI/or OMCPI. The glass transition temperature as determined from DSC scans was found to increase with increasing amounts of OMPCI in copolymers. A significant improvement in the char yield as determined by thermogravimetry was observed upon copolymerization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2391–2398, 2006  相似文献   

16.
Ammonium itaconate was first used to copolymerize with acrylonitrile. This was achieved by using azobisisobutyronitrile as the initiator and dimethyl sulfoxide as the solvent. Effects of copolymerization systems on monomer apparent reactivity ratios for acrylonitrile/ammonium itaconate copolymers were studied. The values of monomer apparent reactivity ratios were calculated by Kelen‐Tudos method. The apparent reactivity ratios in the aqueous suspension polymerization system are similar to those in the solution polymerization system at polymerization conversions of less than 18% [reactivity ratio of acrylonitrile (rAN) = 0.47 ± 0.01, reactivity ratio of ammonium itaconate (rAIA) = 3.08 ± 0.01]. At conversions of more than 50%, the changes of monomer apparent reactivity ratios become less prominent (rAN = 0.68 ± 0.01, rAIA = 2.47 ± 0.01). In water‐rich reaction medium [(H2O/dimethylsulfoxide (DMSO) > 80/20)], the monomer apparent reactivity ratios are approximately equivalent to those in the aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H2O > 80/20), the apparent reactivity ratios are similar to those in the solution polymerization system. With an increase in the polarity of the solvent, the values of apparent reaction ratios both decrease. The values of apparent reaction ratios gradually tend to 1 with increasing the copolymerization temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3920–3923, 2007  相似文献   

17.
Optically active 2-endo-actoxy-5-endo-bornyl methacrylate (ABMA) was prepared from (+)-camphor. The homopolymerization of ABMA and copolymerization of ABMA with achiral methyl methacrylate (MMA) or styrene (St) were carried out with 2,2′-azobisisobutyronitrile (AIBN) in benzene. Effects of temperature, solvents, and reaction time on the copolymerization were discussed. The monomer reactivity ratios(r1, r2) for poly(ABMA-co-MMA) and poly(ABMA-co-St) and Q and e values for the chiral ABMA in the copolymerization systems were evaluated by the Fineman—Ross method. The absolute value of the specific rotation of poly(ABMA-co-MMA) increased with increasing ABMA unit content. A small deviation from linearity was observed, which suggests that asymmetry is not introduced into the copolymer main chain. Temperature and solvent effects on the specific rotation of the chiral homopolymer and copolymers were investigated. The results suggest that the chiral polymers synthesized in this investigation did not show a strong preference for a particular helical conformation. Applications of the chiral polymers on the asymmetric addition of n-butyllithium to aldehydes were also discussed.  相似文献   

18.
Yongjun Li  Sheng Chen  Qingnuan Li  Guolin Lu  Hao Liu 《Polymer》2009,50(22):5192-4440
A new methacrylate monomer containing perfluorocyclobutyl and sulfonyl units, p-(2-(p-(benzenesulfonyl)phenoxy)perfluorocyclobutoxy)phenyl methacrylate, was synthesized from commercially available reagents in good yield and this kind of methacrylate can be homopolymerized by free radical polymerization using 2,2′-azobis(isobutyronitrile) as initiator or atom transfer radical polymerization using methyl 2-bromopropionate as initiator and CuBr/PMDETA as catalytic system. The reactivity ratios for BSPPFCBPMA and MMA were found to be r1 = 1.2436 and r2 = 0.8171 determined by Fineman-Ross method, and r1 = 1.2279 and r2 = 0.8023 by Kelen-Tudos method respectively. The resultant polymethacrylates bearing perfluorocyclobutyl and sulfonyl functionalities exhibit excellent thermal stability as evidenced from thermogravimetric analysis and the decomposition temperature rose dramatically with the increasing of molecular weights. Random copolymers of BSPPFCBPMA and methyl methacrylate were obtained by free radical copolymerization and their thermo-stabilities increase while raising the contents of BSPPFCBPMA.  相似文献   

19.
New functional monomers mono-and dimethacryloyl isocyanate containing bisphenol-A were prepared on reaction of methacryloyl isocyanate (MAI) with bisphenol-A (BPA) and its derivatives at low temperature. The monomers thus obtained were characterized with IR, UV, and 1H- and 13C-NMR spectra. Radical polymerization of mono-and dimethacryloyl isocyanate containing bisphenol-A and its derivatives was studied in terms of the rate of polymerization, solvent effect, copolymerization, thermal properties, and kinetic measurements of photocrosslinking. Polar solvents such as DMSO and NMP were found to slow the polymerization. Copolymerization of BPA-MAI (M1) with MMA (M2) in DMF was studied at 90°C. The monomer reactivity ratio was calculated to be r1 = 0.17 and r2 = 1.34 according to the method of Fineman–Ross. Functional polymers containing the allyl group were successfully modified and photocrosslinked on irradiation in the presence of benzoin isopropyl ether. The photocrosslinking process follows second-order kinetics. © 1996 John Wiley & Sons, Inc.  相似文献   

20.
The article describes the synthesis and characterization of N‐aryl itaconimide monomers such as: N‐(p‐chlorophenyl) itaconimide (PI)/N‐(m‐chlorophenyl) itaconimide (MI)/N‐(o‐chlorophenyl) itaconimide (OI) and its copolymerization behavior with MMA. The homopolymers and copolymers of N‐aryl itaconimides and methyl methacrylate (MMA, M2) were synthesized by varying the mol fraction of N‐aryl itaconimides in the initial feed from 0.1 to 0.5 using azobisisobutyronitrile (AIBN) as an initiator and tetrahydrofuran (THF) as the solvent. Copolymer composition was determined using 1H‐NMR spectroscopy [by taking the ratio of intensities of signals due to ? OCH3 of MMA (δ = 3.59 ppm) and the aromatic proton (δ = 7.2–7.5 ppm) of N‐aryl itaconimides] and percent nitrogen content. The reactivity ratios were found to be r1 = 1.33 and r2 = 0.36 (PI‐MMA) r1 = 1.15 and r2 = 0.32 (MI‐MMA) and r1 = 0.81 and r2 = 0.35 (OI‐MMA). Molecular weight as determined using high‐performance liquid chromatography decreased with increasing mol fraction of itaconimides in copolymers. All the polymers had a polydisperstivity index in the range of 1.5–2.6.Thermal characterization was done using differential scanning calorimetry and dynamic thermogravimetry in nitrogen atmosphere. Incorporation of these N‐aryl itaconimides in PMMA backbone resulted in an improvement in glass transition temperature (Tg) and thermal stability. Percent char increased with the increase of PI/MI/OI content in the copolymers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2078–2086, 2001  相似文献   

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