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1.
Statistical copolymers of N‐vinylpyrrolidone (NVP) with 2‐(dimethylamino)ethyl methacrylate (DMAEMA) were prepared by Reversible Addition‐Fragmentation chain Transfer Polymerization (RAFT), employing three different RAFT agents: [(O‐ethylxanthyl)methyl]benzene, [1‐(O‐ethylxanthyl)ethyl]benzene, and O‐ethyl S‐(phthalimidylmethyl) xanthate. The reactivity ratios were estimated using the Fineman‐Ross, inverted Fineman‐Ross, Kelen‐Tüdos, and extended Kelen‐Tüdos graphical methods, along with the computer program COPOINT. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the mean sequence length. All the methods indicate that the DMAEMA reactivity ratio is much greater than the one of NVP, thus, the statistical copolymers are in fact pseudo‐diblocks. The glass‐transition temperature (Tg) values of the copolymers were measured by Differential Scanning Calorimetry. Furthermore, a systematic and detailed investigation has been done, on the thermal degradation of the copolymers compared with the respective homopolymers, by Thermogravimetric Analysis, within the framework of the Ozawa‐Flynn‐Wall and Kissinger methodologies. Apparently, the thermal stability of the copolymers is influenced by both monomers and by the structure of the thiocarbonylthio end groups due to the RAFT agents. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3776–3787  相似文献   

2.
Statistical copolymers of norbornene (NBE) with 5‐vinyl‐2‐norbornene (VNBE) were prepared by ring‐opening metathesis polymerization, employing the triply bonded ditungsten complex Na[W2(μ‐Cl)3Cl4(THF)2].(THF)3. NMR measurements revealed that the side vinyl groups of the VNBE monomer remain intact during the copolymerization reaction. The reactivity ratios were estimated using the Finemann–Ross (FR), the inverted FR, and the Kelen–Tüdos graphical methods. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions, which were derived using the monomer reactivity ratios. The glass transition temperatures, Tg, of the copolymers were measured by differential scanning calorimetry measurements and were examined in the frame of several theoretical equations allowing the prediction of these Tg values. The best fit was obtained using methods that take into account the monomer sequence distribution of the copolymers. Finally, the kinetics of the thermal decomposition of the copolymers was studied by thermogravimetric analysis in the frame of the Ozawa–Flynn–Wall and Kissinger methods. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4835–4844  相似文献   

3.
Statistical copolymers of methyl methacrylate with cyclohexyl and trimethylsilyloxy ethyl methacrylate were synthesized with two different catalytic systems based on the zirconocene complex Cp2ZrMe2. The reactivity ratios of methyl methacrylate and these methacrylates were calculated with the Finemann–Ross, inverted Finemann–Ross, and Kelen–Tüdos graphical methods. The structural parameters of these copolymers were estimated from the calculation of the dyad monomer sequence fractions. Two different borate cocatalysts were employed, and their effect on the copolymerization process is discussed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3305–3314, 2005  相似文献   

4.
Radical copolymerization based on acrylonitrile (AN) and 2,2,2‐Trifluoroethyl acrylate (ATRIF) initited by AIBN was investigated in acetonitrile solution. The resulting poly(AN‐co‐ATRIF) copolymers were characterized by 1H, 13C, and 19F NMR and IR spectroscopy, and size exclusion chromatography (SEC). Their compositions were assessed by 1H NMR. The kinetics of radical copolymerization of AN with ATRIF was investigated from sereval experiments achieved at 70 °C from initial [AN]0/[ATRIF]0 molar ratios ranging between 20/80 and 80/20 and was enabled to determine the reactivity ratios of both comonomers. From the monomer—polymer copolymerization curve, the Fineman–Ross and Kelen–Tüdos laws enabled to assess the reactivity ratios (rAN= r1 = 1.25 ± 0.04 and rATRIF = r2 = 0.93 ± 0.05 at 70 °C) while the revised patterns scheme led to r12 = rAN = 1.03, and r21 = rATRIF = 0.78 at 70 °C. In all cases, rAN x rATRIF product was close to unity, which indicates that poly(AN‐co‐ATRIF) copolymers exhibit a random structure. This was also confirmed by the Igarashi's and Pyun's laws which revealed the presence of AN‐ATRIF, AN‐AN, and ATRIF‐ATRIF dyads. The Q and e values for ATRIF were also assessed (Q2 = 0.62 and e2 = 0.93). The glass transition temperature values, Tg, of these copolymers increased from 17 to 61 °C as the molar percentage of ATRIF decreased from 77 to 16% in the copolymer. Thermogravimetry analysis of poly(AN‐co‐ATRIF) copolymers showed a good thermal stability compared to that of poly(ATRIF) homopolymer due to incorporation of AN comonomer. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3856–3866  相似文献   

5.
The new acrylic monomer 4‐propanoylphenyl acrylate (PPA) was synthesized and copolymerized with methyl methacrylate (MMA) in methyl ethyl ketone at 70±1°C using benzoyl peroxide as a free radical initiator. The copolymers were characterized by FT‐IR, 1H‐NMR and 13C‐NMR spectroscopic techniques. The compositions of the copolymers were determined by 1H‐NMR analysis. The reactivity ratios of the monomers were determined using Fineman‐Ross (r1=0.5535 and r2=1.5428), Kelen‐Tüdös (r1=0.5307 and r2=1.4482), and Ext. Kelen‐Tüdös (r1=0.5044 and r2=1.4614), as well as by a nonlinear error‐in‐variables model (EVM) method using a computer program, RREVM (r1=0.5314 and r2=1.4530). The solubility of the polymers was tested in various polar and non‐polar solvents. The elemental analysis was determined by a Perkin‐Elmer C‐H analyzer. The molecular weights (Mw and Mn) of the copolymers were determined by gel permeation chromatography. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with an increase in the mole fraction of MMA in the copolymers. Glass transition temperatures of the copolymers were found to increase with an increase in the mole fraction of MMA in the copolymers.  相似文献   

6.

The new acrylamide monomer, N‐(4‐Bromophenyl)‐2‐methacrylamide (BrPMAAm) has been synthesized by reacting 4‐Bromoaniline with methacryloyl chloride in the presence of triethylamine(NR3) at 0–5°C. The radical‐initiated copolymerization of (BrPMAAm), with 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) has been carried out in dimethylformamide (DMF) solution at 70±1°C using 2,2′‐azobisisobutyronitrile (AIBN) as an initiator with different monomer‐to‐monomer ratios in the feed. The copolymers were characterized by FTIR, 1H‐ and 13C‐NMR spectroscopy. The copolymer composition was evaluated by nitrogen content (N for AMPS‐units) in polymers led to the determination of reactivity ratios. The monomer reactivity ratios for BrPMAAm (M1)‐AMPS (M2) pair were computed using the Fineman‐Ross (F‐R), Kelen‐Tüdös (KT) and Extended Kelen‐Tüdös (EKT) methods. These parameters were also estimated using a non‐linear computational fitting procedure, known as reactivity ratios error in variable model (RREVM). The mean sequence lengths determination indicated that the copolymer was statistically in nature. By TGA and DSC analyses, the thermal properties of the polymers have been studied. The antimicrobial effects of polymers were also tested on various bacteria, and yeast.  相似文献   

7.
The radical copolymerization of three polymerizable surfactants with styrene was investigated by NMR spectroscopy to assess their compositions. The reactivity ratios of these monomers were calculated according to the methods of Fineman–Ross and Kelen–Tüdos. Consequently, Q and e values were deduced by the Alfrey and Price method. The results indicated the positive effect of the fluorine chain on the reactivity of monomers bearing a long spacer between the ammonium head and the acrylic function. These monomers exhibit high e values which are in favor of an intramolecular conformation of the surfactant where the ester carbonyl function of the polymerizable group interacts with the onium nitrogen atom via a compact six-sided structure.  相似文献   

8.
We report the monomer reactivity ratios for copolymers of methyl methacrylate (MMA) and a reactive monomer, 2‐vinyl‐4,4′‐dimethylazlactone (VDMA), using the Fineman–Ross, inverted Fineman–Ross, Kelen–Tudos, extended Kelen–Tudos, and Tidwell–Mortimer methods at low and high polymer conversions. Copolymers were obtained by radical polymerization initiated by 2,2′‐azobisisobutyronitrile in methyl ethyl ketone solutions and were analyzed by NMR, gas chromatography (GC), and gel permeation chromatography. 1H NMR analysis was used to determine the molar fractions of MMA and VDMA in the copolymers at both low and high conversions. GC analysis determined the molar fractions of the monomers at conversions of less than 27% and greater than 65% for the low‐ and high‐conversion copolymers, respectively. The reactivity ratios indicated a tendency toward random copolymerization, with a higher rate of consumption of VDMA at high conversions. For both low‐ and high‐conversion copolymers, the molecular weights increased with increasing molar fractions of VDMA, and this was consistent with the faster consumption of VDMA (compared with that of MMA). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3027–3037, 2003  相似文献   

9.
Abstract

Copolymers of p-nitrobenzyl acrylate and methyl acrylate with different feed ratios are synthesized in ethyl methyl ketone using benzoyl peroxide as a free radical initiator at 70 ± 1°C. The copolymers were characterized by IR and 1H-NMR spectroscopic techniques. Copolymer compositions were determined by 1H-NMR analysis of the polymers. The monomer reactivity ratios were determined by the application of conventional linearization methods such as Fineman–Ross and Kelen–Tüdös. Gel permeation chromatography was used for determining the molecular weights M n and M w, and the polydispersity index. The intrinsic viscosities and the thermal properties of the homo- and copolymers are also discussed.  相似文献   

10.
We investigated the mechanism of the ring‐opening copolymerization of ?‐caprolactam (?‐CL) with glycidyl phenyl ether (GPE) to afford poly(?‐CL‐co‐GPE) as a model reaction of the thermal curing of certain epoxy resins with ?‐CL. The reaction of ?‐CL and GPE proceeded efficiently in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) at 170°C for 2 h. The monomer reactivities r1 of ?‐CL and r2 of GPE calculated according to the Fineman‐Ross method and the Kelen‐Tüdös method were 0.58 and 5.52, respectively. These values indicate that poly(?‐CL‐co‐GPE) has a pseudo‐block gradient copolymer. Based on these results, we examined the thermal curing reactions of certain epoxy resins with ?‐CL. The corresponding novel cured products were obtained quantitatively, and each of them showed a high glass transition temperature and high thermal stability, presumably due at least in part to a pseudo‐block gradient primary structure resembling that of poly(?‐CL‐co‐GPE). © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2220–2228  相似文献   

11.
Statistical copolymers of 2-vinylpyridine (VP) with oligo(ethylene glycol) methyl ether methacrylates of two different molecular weights (300 g/mol (OEGMA300) and 1100 g/mol (OEGMA1100)), were prepared by free radical polymerization. The reactivity ratios of these two sets of monomers were estimated using the Finemann–Ross, the inverted Finemann–Ross and the Kelen–Tüdos graphical methods. Structural parameters of the copolymers were obtained by calculating the dyad monomer sequence fractions and the mean sequence length. The effect of the length of the oligo(ethylene glycol) group on the copolymer structure is discussed. The glass-transition temperature (Tg) values of the VP copolymers with OEGMA300 were measured and examined in the frame of several theoretical equations, allowing the prediction of these Tg values. The copolymers of VP with OEGMA1100 exhibited the characteristic melting endotherm, due to the crystallinity of the methacrylate sequences and glass transition temperatures attributed to the PVP sequences.  相似文献   

12.
A series of well‐defined amphiphilic graft copolymers, containing hydrophilic poly(acrylic acid) backbone and hydrophobic poly(butyl acrylate) side chains, were synthesized by sequential reversible addition fragmentation chain transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP) without any postpolymerization functionality modification followed by selective acidic hydrolysis of poly(tert‐butyl acrylate) backbone. tert‐Butyl 2‐((2‐bromopropanoyloxy)methyl)‐acrylate was first homopolymerized or copolymerized with tert‐butyl acrylate by RAFT in a controlled way to give ATRP‐initiation‐group‐containing homopolymers and copolymers with narrow molecular weight distributions (Mw/Mn < 1.20) and their reactivity ratios were determined by Fineman‐Ross and Kelen‐Tudos methods, respectively. The density of ATRP initiation group can be regulated by the feed ratio of the comonomers. Next, ATRP of butyl acrylate was directly initiated by these macroinitiators to synthesize well‐defined poly(tert‐butyl acrylate)‐g‐poly(butyl acrylate) graft copolymers with controlled grafting densities via the grafting‐from strategy. PtBA‐based backbone was selectively hydrolyzed in acidic environment without affecting PBA side chains to provide poly(acrylic acid)‐g‐poly(butyl acrylate) amphiphilic graft copolymers. Fluorescence probe technique was used to determine the critical micelle concentrations in aqueous media and micellar morphologies are found to be spheres visualized by TEM. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2622–2630, 2010  相似文献   

13.

The copolymerization of 2‐(3‐(6‐tetralino)‐3‐methyl‐1‐cyclobutyl)‐2‐hydroxyethyl methacrylate (TCHEMA), monomer with acrylonitrile and 4‐vinylpyridine were carried out in 1,4‐dioxane solution at 65°C using AIBN as an initiator. The copolymers were characterized by FTIR, 1H‐NMR, and 13C‐NMR spectroscopic techniques. Thermal properties of the polymers were also studied by thermogravimetric analysis and differential scanning calorimetry. The copolymer compositions were determined by elemental analysis. The monomer reactivity ratios were calculated by the Fineman‐Ross and Kelen‐Tüdös method. Also, the apparent thermal decomposition activation energies were calculated by the Ozawa method with a Shimadzu TGA 50 thermogravimetric analysis thermobalance.  相似文献   

14.
Repeating sequence copolymers of poly(lactic‐co‐caprolactic acid) (PLCA), poly(glycolic‐co‐caprolactic acid) (PGCA), and poly(lactic‐co‐glycolic‐co‐caprolactic acid) (PLGCA) have been synthesized by polymerizing segmers with a known sequence in yields of 50–85% with Mns ranging from 18–49 kDa. The copolymers exhibited well‐resolved NMR resonances indicating that the sequence encoded in the segmers used in their preparation is retained and that transesterification is minimal. The exact sequences allowed for unambiguous assignment of the NMR spectra, and these standards were compared with the data previously reported for random copolymers. The glass transition temperatures (Tgs) of the PLCA and PGCA copolymers were found to depend primarily on monomer ratio rather than sequence. Sequence dependent Tgs were, however, noted for the PLGCA polymers with 1:1:1 L:G:C ratios; poly LGC and poly GLC exhibited Tgs that differed by nearly 8 °C. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011  相似文献   

15.
Copolymerizations of ethylene and tricyclopentadiene (TCPD) are realized without formation of a gel with a high activity (3–18 × 106 g/molZr·h) using a catalytic system of [Ph2C(Flu)(Cp)]ZrCl2/MMAO. The monomer reactivity ratios, rethylene and rTCPD, determined through the Fineman‐Ross plot, are 6.4 and 0.044, respectively, indicating that TCPD insertion is unfavorable, negligibly allowing the successive TCPD insertions. A significant higher glass transition temperature (Tg) is attained than those observed for other reported cycloolefin copolymers at the same cycloolefin content. A Tg as high as 214 °C is attainable at 41 mol % TCPD content. The remaining double bond can be hydrogenated to saturated hydrocarbon or converted to an epoxide group. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011  相似文献   

16.

We report the monomer reactivity ratios for copolymers of ethyl methacrylate (EMA) and a reactive monomer, 2‐[(5‐methylisoxazol‐3‐yl)amino]‐2‐oxo‐ethyl methacrylate (IAOEMA), using the Fineman‐Ross, Kelen‐Tüdös, and a nonlinear error invariable model method using a computer program RREVM. Copolymers were obtained by radical polymerization initiated by α,α'‐azobisisobutyronitrile in 1,4‐dioxane solution and were analyzed by FTIR, 1H‐NMR, and gel permeation chromatography. Elemental analysis was used to determine the molar fractions of EMA and IAOEMA in the copolymers. The reactivity ratios indicated a tendency toward ideal copolymerization. The polydispersity indices of the polymers determined using gel permeation chromatography suggest a strong tendency for chain termination by disproportionation. Thermal behaviors of copolymers with various compositions were investigated by differential scanning calorimetry and thermogravimetric analysis. It was observed that glass transition temperature of copolymers increased with increasing of IAOEMA content in copolymers. Also, the apparent thermal decomposition activation energies (ΔEd) were calculated by Ozawa method using the SETARAM Labsys TGA thermobalance. The homo‐ and copolymers were tested for their antimicrobial properties against selected microorganisms. All the products show moderate activity against different strains of bacteria, fungi and yeast.  相似文献   

17.

New methacrylate monomers, 2‐{[(diphenylmethylene)amino]oxy}‐2‐oxoethyl methacrylate (DPOMA) and 2‐{[(1‐phenylethylidene)ami no]oxy}‐2‐oxoethyl methacrylate (MMOMA) were prepared by reaction of sodium methacrylate with diphenylmethanone O‐(2‐chloroacetyl) oxime and 1‐phenylethanone O‐(2‐chloroacetyl) oxime, respectively. They were obtained from a reaction of chloroacetyl chloride with benzophenone oxime or acetophenone oxime. The free‐radical‐initiated copolymerization of (DPOMA) and (MMOMA) with styrene (St) were carried out in 1,4‐dioxane solution at 65°C using 2,2‐azobisisobutyronitrile (AIBN) as an initiator with different monomer‐to‐monomer ratios in the feed. The monomers and copolymers were characterized by FTIR, 1H‐ and 13C‐NMR spectral studies. The copolymer compositions were evaluated by nitrogen content in polymers. The reactivity ratios of the monomers were determined by the application of Fineman–Ross and Kelen–Tüdös methods. The molecular weights (M¯w and M¯n) and polydispersity index of the polymers were determined by using gel permeation chromatography. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with an increase in the mole fraction of St in the copolymers. The activation energies of the thermal degradation of the polymers were calculated with the MHRK method. Glass transition temperatures of the copolymers were found to decrease with an increase in the mole fraction of DPOMA or MMOMA in the copolymers. The antibacterial and antifungal effects of the monomers and polymers were also investigated on various bacteria and fungi. The photochemical properties of the polymers were investigated by UV and FTIR spectra.  相似文献   

18.
Bulk nitroxide‐mediated polymerization (NMP) of β‐myrcene (My)/glycidyl methacrylate (GMA) mixtures with varying GMA molar feed fraction (fGMA,0 = 0.10–0.91) was accomplished at 120 °C, initiated by SG1‐based alkoxyamine bearing a N‐succinimidyl ester group (NHS‐BlocBuilder). Low dispersity My/GMA copolymers (Đ < 1.56) with slight number‐average molecular weights (Mns) deviations from predicted values (Mn,theo with Mn/Mn,theo > 70%) were obtained. The copolymerization was revealed to be statistical, confirmed via Fineman–Ross (rMy = 0.80 ± 0.31 and rGMA = 0.71 ± 0.15) and Kelen‐Tüdös (rMy = 0.48 ± 0.12 and rGMA = 0.53 ± 0.18) approaches. Glass transition temperature (Tg) of the statistical P(Mystat‐GMA)s increased from −77 to +43 °C as the GMA molar fraction incorporated (FGMA) increased from 0.10 to 0.90. High SG1 chain‐end fidelity for My‐rich and GMA‐rich P(Mystat‐GMA)s was assessed by phosphorus nuclear magnetic resonance (31P NMR, SG1 fraction >69 mol %) and chain‐extensions in toluene with My, GMA and styrene (S) (monomodal shift in Mn). Last, diblock P(Myb‐GMA) was made and treated with morpholine to produce amphiphilic copolymer able to self‐organize into micelles. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 860–878  相似文献   

19.

A new methacrylic monomer, 4‐nitro‐3‐methylphenyl methacrylate (NMPM) was prepared by reacting 4‐nitro‐3‐methyl phenol dissolved in methyl ethyl ketone (MEK) in the presence of triethylamine as a catalyst. Copolymerization of NMPM with methyl methacrylate (MMA) has been carried out in methyl ethyl ketone (MEK) by free radical solution polymerization at 70±1°C utilizing benzoyl peroxide (BPO) as initiator. Poly (NMPM‐co‐MMA) copolymers were characterized by FT‐IR, 1H‐NMR and 13C‐NMR spectroscopy. The molecular weights (Mw and Mn) and polydispersity indices (Mw/Mn) of the polymers were determined using a gel permeation chromatograph. The glass transition temperatures (Tg) of the copolymers were determined by a differential scanning calorimeter, showing that Tg increases with MMA content in the copolymer. Thermogravimetric analysis of the polymers, performed under nitrogen, shows that the stability of the copolymer increases with an increase in NMPM content. The solubility of the polymers was tested in various polar and non‐polar solvents. Copolymer compositions were determined by 1H‐NMR spectroscopy by comparing the integral peak heights of well separated aromatic and aliphatic proton peaks. The monomer reactivity ratios were determined by the Fineman‐Ross (r1 =7.090:r2=0.854), Kelen‐Tudos (r1=7.693: r2=0.852) and extended Kelen‐Tudos methods (r1=7.550: r2= 0.856).  相似文献   

20.
This investigation reports the atom transfer radical copolymerization (ATRcP) of glycidyl methacrylate (GMA) and 2‐ethylhexyl acrylate (EHA). Poly(glycidyl methacrylate) (PGMA) has easily transformable pendant oxirane group and poly(2‐ethylhexyl acrylate) (PEHA) has very low Tg. They are the important components of coating and adhesive materials. Copolymerization of GMA and EHA was carried out in bulk and in toluene at 70 °C at different molar feed ratios using CuCl as catalyst in combination with 2,2′‐bypyridine (bpy) as well as N,N,N′,N″,N″‐pentamethyl diethylenetriamine (PMDETA) as ligand. The molecular weight (Mn) and the polydispersity index (PDI) of the polymers were determined by GPC analysis. The molar composition of the copolymers was determined by 1H NMR analysis. The reactivity ratios of GMA (r1) and EHA (r2) were determined using Finemann‐Ross and Kelen‐Tudos linearization methods and those had been compared with the literature values for conventional free radical copolymerization. The thermal properties of the copolymers were studied by DSC and TGA analysis. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6526–6533, 2009  相似文献   

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