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1.
Sevil DinçerVolkan Köseli Hande KesimZakir M.O Rzaev Erhan Pi?kin 《European Polymer Journal》2002,38(11):2143-2152
Radical-initiated copolymerization of N-isopropylacrylamide (NIPA) with maleic (MA) and citraconic (CA) anhydrides was carried out in the presence of 2,2′-azobisisobutyronitrile (AIBN) as an initiator in 1,4-dioxane at 65 °C under nitrogen atmosphere. Structure and monomer unit compositon of the copolymers obtained from a wide range of monomer feed were determined by elemental analysis (content of N for NIPA units), Fourier transform infrared and 1H NMR spectroscopy. Monomer reactivity ratios for NIPA (M1)-MA (M2) and NIPA (M1)-CA (M2) pairs were determined by Kelen-Tüdõs (KT) and non-linear regression (NLR) methods using elemental and 1H NMR spectroscopy analyses data. They are r1=0.45 and r2=0.08 (KT, N analysis), r1=0.44 and r2=0.10 (KT, 1H NMR), r1=0.45 and r2=0.078 (NLR) for NIPA-MA monomer pair and r1=0.52 and r2=0.02, r1=0.44 and r2=0.04, r1=0.51 and r2=0.014 for NIPA-CA monomer pair, respectively. Observed tendency towards alternating copolymerization at ?50 mol% NIPA concentration in monomer feed and relatively high activity of NIPA growing radical was explained by H-bond formation between CO (anhydride) and NH (amide) fragments during chain growth reactions. Intrinsic viscosity, molecular weight and thermal behaviour of the synthesized copolymers were found to depend on the type of comonomer and the amount of NIPA units in the copolymers. These functional amphiphilic copolymers containing anion- and cation-active groups show both temperature and pH sensitivity and can be used for biological purposes as physiologically active macromolecular systems. 相似文献
2.
Statistical copolymers of styrene with trimethylsilyl methacrylate, STMS, and trimethylsilyloxyethyl methacrylate, STME, and of 2-vinylpyridine with trimethylsilyloxyethyl methacrylate, VTME were prepared by free radical copolymerization in benzene with 2,2′-azobisisobutyronitrile, AIBN. The reactivity ratios of the different monomers were estimated using the Finemann-Ross, the inverted Finemann-Ross, and the Kelen-Tüdos or the extended Kelen-Tüdos graphical methods. Structural parameters of the copolymers were obtained by calculating the diad sequence fractions, which were derived using the monomer reactivity ratios. The results were compared with those obtained from the copolymerization of styrene and 2-vinylpyridine with methacrylic acid and 2-hydroxyethyl methacrylate. 相似文献
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4.
Co polymerization of styrene (St) and isoprene (IP) was carried out with a catalyst system composed of anhydrous lanthanide chloride hexamethyl phosphor amide complex (LnC13‐HMPA) and aluminum organic compound (AOC). Among the catalysts examined, catalyst NdC13*HMPA/Al(i‐Bu)3 showed a high activity in the copolymerization under certain conditions giving copolymers (5%‐158 St content) with high cis‐1, 4 microstructure in IP Units (>95%). The effects of HMPA/Nd molar ratio, Al/Nd molar ratio, monomer/Nd molar ratio, St feed ratio, and the reaction time on copolymerization were examined with this catalytic system. The obtained copolymers were characterized by 1H and 13C NMR spectroscopies and gel‐permeation chromatography (GPC). 相似文献
5.
N-对甲苯基甲基丙烯酰胺的合成及与甲基丙烯酸甲酯共聚合的研究 总被引:1,自引:0,他引:1
本文合成了N-对甲苯基甲基丙烯酰胺(N-p-TMA),用IR和NMR进行了表征。制得了N-p-TMA与甲基丙烯酸甲酯(MMA)的共聚体,给出了共聚体的IR和NMR谱。用核磁共振测得N-p-TMA-与-MMA共聚合的竞聚率γN-p-TMA=0.78±0.02,γMMA=1.43±0.02。用热机械曲线测出了共聚体的Tg和Tf,并发现Tg和Tf值随着共聚体中酰胺含量的增加而升高。 相似文献
6.
Copolymerization of butadiene (Bd) and styrene (St) was carried out in toluene at 50 °C by a conventional rare earth catalytic system, Nd(naph)3-Al(i-Bu)3-Al(i-Bu)2Cl. It exhibited a high catalytic activity and high stereospecificity in the copolymerization. The influences of the conditions in polymerization on the yield, composition, microstructure and molecular weight of copolymer were thoroughly studied. According to the 13C-NMR spectrum, the resultant copolymer containing 18% St units, and the diad fraction of St-trans Bd or St-vinyl Bd can hardly be found in its 13C-NMR. The cis-1,4 content of Bd unit of the copolymer decreased little with the increase of St content. The GPC curves indicate the presence of two kinds of active sites in the polymerization. 相似文献
7.
Monomer reactivity ratios for fluoroacrylate and butyl methacrylate in miniemulsion copolymerizations initiated by potassium persulphate 总被引:1,自引:0,他引:1
Miniemulsion copolymerization of butyl mathacrylate(BMA) with fluoroacrylate(HFMA,TFMA) was carried out at 70℃by employing potassium persulphate(KPS) as initiator.Copolymer compositions at low conversion levels were determined by ~1H NMR spectra techniques.The reactivity ratios were evaluated by employing Kellen-Tudos(K-T) methods,which yields the apparent reactivity ratios,r_(BMA)=0.74,r_(HFMA) = 0.87 and r_(BMA) = 0.73,r_(TFMA) = 0.75,respectively,and Q- and e-values of HFMA and TFMA were calculated by... 相似文献
8.
Yuji Minoura Toshio Tadokoro Yasuyuki Suzuki 《Journal of polymer science. Part A, Polymer chemistry》1967,5(10):2641-2654
The monomer reactivity ratios for the radical copolymerization of crotononitrile (CN), methyl crotonate (MC), and n-propenyl methyl ketone (PMK) with styrene (St) were measured at 60°C. in benzene and little penultimate unit effect was shown for these systems. The values obtained were: St–CN, r1 = 24.0, r2 = 0; St–MC, r1 = 26.0, r2 = 0.01; St–PMK, r1 = 13.7, r2 = 0.01. The rate of copolymerization and the viscosity of the copolymer decreased markedly as the molar fraction of the crotonyl compound in the monomer mixture increased. The Q–e values were also calculated to be as follows: CN, e = 1.13, Q = 0.009; MC, e = 0.36, Q = 0.015; PMK, e = 0.61, Q = 0.024. A linear relationship was obtained between the e values of the crotonyl compounds and their Hammett constants σm. 相似文献
9.
Seizo Masuda Keiji MinagawaHirokazu Okamura Masami Tanaka 《European Polymer Journal》2002,38(2):327-331
Continuous variation method in UV revealed that methyl N-acetylaminoacrylate (MNA) and SnCl4 formed the 1:1 complex. The copolymerization of MNA with styrene in tetrahydrofuran was carried out at 50 °C in the presence of SnCl4. The resulting monomer reactivity ratios decreased with an increasing concentration of SnCl4 added. This finding suggests that SnCl4 participates in the propagation step of the copolymerization. Therefore, the copolymerization was analyzed by assuming terpolymerization of free MNA (M1), complexed MNA (M2), and styrene (M3). The absolute copolymerization parameters were obtained as follows: k11/k12=0.165, k11/k13=3.04, k22/k21=0.32, k22/k23=0.103, k33/k31=0.058, k33/k32=0.001, Q1=6.03, e1=0.52, Q2=88.57, and e2=2.23. The complexed MNA is more reactive to polymer radicals with free MNA and styrene as the terminal unit than the free MNA. Very small values of k22/k23 and k33/k32 suggests that the copolymerization of the complexed MNA and styrene proceeds alternatingly. 相似文献
10.
A series of cationic surfmers with benzyl groups(QARBCs)with different R groups on the benzene ring were synthesized and characterized by IR,1H-NMR,13C-NMR.The aggregation of QARBCs was studied by the steady-state fluorescence technique.It turned out that QARBCs had surface activity and their critical micelle concentration(CMC)values varied in the range of 10-2—10-3mol/L with slight increase with temperature.The copolymerization of acrylamide(M1)and QARBCs(M2)was studied below and above CMC,their reactivity ratios were determined by the Finemann-Ross method.It was found that below CMC,copolymerization took place in a homogeneous system and reactivity ratios of acrylamide and QARBCs were less than 1;while above CMC,reactivity ratios of QARBCs were greater than 1.The copolymerization mechanism of QARBC was observed to be similar to that of micellar polymerization.QARBCs tended to homopolymerization,which gave rise to micro-blocky sequences in the polymer backbone.The Q and e values of QARBCs were calculated according to the Alfrey-Price equation by using r1(AM)and r2(qarBC).Samples of poly(AM-co-QARBC) were prepared above and below CMC and their hydrophobic associations were studied by the steady-state fluorescence spectra and 2D NOESY spectra,and their critical associating concentrations(CAC)were estimated.The results showed that samples of poly(AM-co-QARBC)prepared above CMC had stronger hydrophobic association in aqueous solution than those prepared below CMC. 相似文献
11.
Saroj Sharma 《European Polymer Journal》2004,40(9):2235-2240
The radical copolymerization of limonene with styrene by azobisisobutyronitrile in xylene at 80 ± 0.1 °C for 2 h, under inert atmosphere of N2, yields alternating copolymers. The kinetic expression is Rp∝[I]0.5[Sty]1.0[Lim]−1.0. The overall activation energy is calculated as 41 kJ/mol. The FTIR and 1H-NMR spectra of copolymers show bands at 3000 and 1715 cm−1 and peaks at 6.8 δ and 5.3 δ due to phenyl protons of styrene and trisubstituted olefinic protons of limonene, respectively. The values of reactivity ratios r1(Sty)=0.0625 and r2(Lim)=0.014, calculated by Kelen-Tüdos method. The Alfrey-Price Q-e parameters for limonene are 0.438 and −0.748, respectively. The penultimate unit effect is favoured in the present system and the value of φ is 38.49. 相似文献
12.
V. A. Myagchenkov V. F. Kurenkov 《Journal of polymer science. Part A, Polymer chemistry》1969,7(12):3279-3286
Heterogeneous copolymerization of acrylamide with maleic acid has been investigated. The process was carried out at 70°C in 1,4-dioxane. The polarographic method of analysis was applied. The analysis of the experimental and theoretical composition distribution curves has shown an anomalously large composition polydispersion for the experimental distribution curves. This is attributed to the heterogeneity of the copolymerization process. 相似文献
13.
The emulsion copolymerization of styrene and methacrylic acid (MAA) was performed in the presence of a relatively new macromonomer,
poly(ethylene glycol) ethyl ether methacrylate (PEG-EEM) as a stabilizer. In contrast to similar studies, a macromonomer having
relatively shorter polyethylene oxide chain length (i.e., Mn:246, n ≈ 3.0) was selected for this study. Highly uniform and carboxyl functionalized latex particles in the size range of
0.16–0.50 μm were obtained by changing MAA, PEG-EEM, total monomer, and initiator concentrations. The use of PEG-EEM as a
stabilizer resulted in larger monodisperse particles relative to those obtained by the emulsifier-free emulsion copolymerization
of styrene and MAA. The particle size decreased and the polymerization rate increased with the increasing MAA feed concentration.
The application of power law model indicated that MAA concentration was more effective in the presence of PEG-EEM for control
of particle size relative to similar systems. The latex particles with higher numbers of surface-carboxyl groups were obtained
with the higher MAA feed concentrations. Although the particle size decreased and the polymerization rate increased with the
increasing PEG-EEM concentration in the emulsion polymerization of styrene, both of them remained roughly constant with the
increasing PEG-EEM concentration in the presence of MAA.
Received: 21 December 2000 Accepted: 13 July 2000 相似文献
14.
Judit E. Puskas Sam W. P. Chan Kimberley B. Mcauley Gabor Kaszas Sohel Shaikh 《Journal of polymer science. Part A, Polymer chemistry》2007,45(9):1778-1787
The carbocationic copolymerization of isobutylene (IB) and styrene (St), initiated by 2‐chloro‐2,4,4‐trimethylpentane/TiCl4 in 60/40 (v/v) methyl chloride/hexane at ?90 °C, was investigated. At a low total concentration (0.5 mol/L), slow initiation and rapid monomer conversion were observed. At a high total comonomer concentration (3 mol/L), living conditions (a linear semilogarithmic rate and Mn–conversion plots) were found, provided that the St concentration was above a critical value ([St]0 ~ 0.6 mol/L). The breadth of the molecular weight distribution decreased with increasing IB concentration in the feed, reaching Mw/Mn ~ 1.1. St homopolymerization was also living at a high total concentration, yielding polystyrene with Mn = 82,000 g/mol, the highest molecular weight ever achieved in carbocationic St polymerization. An analysis of this system by both the traditional gravimetric–NMR copolymer composition method and FTIR demonstrated penultimate effects. IB enrichment was found in the copolymers at all feed compositions, with very little drift at a high total concentration and above the critical St concentration. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1778–1787, 2007 相似文献
15.
A. KAIM 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):577-588
ABSTRACT The terminal and penultimate model reactivity ratios for the styrene-acrylonitrile monomer system in bulk have been investigated by the simplex and scanning method. It has been shown that Mayo-Lewis equation has an unique solution when determining the reactivity ratios according to the terminal model while for the penultimate model the non-uniqueness in determination of the reactivity ratios has been found. The numerical values of the penultimate r-parameters calculated with the simplex method depend on the initial guess for r-parameters. Several sets of penultimate reactivity ratios for the styrene-acrylonitrile system in bulk have been found to be equal from mathematical point of view. The reactivity ratios with comparable standard deviation have an equivalent graphical representation on the copolymerization diagragm. It has been also confirmed that the penultimate model is a more appropriate of the models considered to describe the variation of the copolymer composition with the monomer feed. Taking into account previous results for the styrene-methyl methacrylate system in bulk it is thereby assumed that the occurrence non-uniqueness in determination of the penultimate model reactivity ratios does not depend on the monomer system. 相似文献
16.
The γ-ray-induced copolymerization of styrene and the surfactant monomer (surfmer) (11-acryloyloxy)undecyltrimethylammonium
bromide, 1, – with and without the presence of the nonreactive surfactant N-dodecyltrimethyammonium bromide, 2, – was studied in a single-phase (1Φ) oil-in-water microemulsion. Upon exchange of 50 weight percent of 1 against 2 the 1Φ region could be increased to higher styrene content. Upon γ-ray irradiation a copolymer is formed: this copolymer
exhibits a larger styrene-to-surfmer ratio than the original monomer mixture. This allowed the styrene-to-surfmer molar ratio
in the resulting polymer to be varied from 0:1 to 4.3:1. The larger styrene-to-surfmer ratio originates from the simultaneous
formation of homopolymer P-1, which is in accordance with the Candau–Leong–Fitch model of polymerization. Further information on particle size and material
properties of the copolymers, which is not accessible by other preparation methods, is also given.
Received: 30 July 1999 /Accepted: 24 November 1999 相似文献
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气相色谱法测定共聚合竞聚率的研究 总被引:2,自引:0,他引:2
以苯乙烯和甲基丙烯酸正丁酯共体系为例,在共聚单体敏感点组成附近做重复实验,进行了40、60、80、100、120℃下的低转化率的共聚合,用气相色谱测定共聚物的组成,用Mayo-Lewis微分组成方程的误差变量法计算竞聚率,同时给出竞聚率的95%可信椭圆区间。通过与FTIR、NMR方法的比较,对气相色谱法测定竞聚率的准确性进行了讨论。 相似文献
19.
The free-radical copolymerization of two N-substituted acrylamide monomers, the ionic AMPS (2-acrylamido-2-methyl-1-propanesulfonic acid) and the non-ionic HEAm (2-hydroxyethylacrylamide) is presented. Despite bearing similar polymerizable functionalities, HEAm is more reactive toward free-radical addition than AMPS in water. In a mixed aqueous solvent containing salt, (0.5 M LiNO3, 50 wt%) and ethanol (50 wt%), the reactivity ratio was found to be rAMPS = 0.53 and rHEAm = 1.06 indicating that copolymers with a nearly random distribution of sulfonic and hydroxy functionalities can be prepared. 相似文献
20.
Conventional free-radical and RAFT copolymerization of poly(ethylene oxide) containing macromonomers
Conventional free-radical and RAFT copolymerization of poly(ethylene oxide) substituent containing methacrylate macromonomers, PEO5MEMA and PEO45MEMA, was studied by the use of 1H NMR spectroscopy for an analysis of residual monomers. From the monomer consumption curves, several parameters including monomer conversion, instantaneous copolymer composition and reactivity ratios of the monomers were evaluated. Reactivity ratios of PEO5MEMA and MAA estimated by non-linear approach of error-in-variables model and presented as joint confidence regions were constant during conventional free-radical and RAFT copolymerizations of the above monomers but were slightly affected by the RAFT process. Reactivity ratio of PEO45MEMA was found to be lower than that of PEO5MEMA and varied during copolymerization: increased with conversion in conventional free-radical copolymerization and slightly (without confidence) decreased in the RAFT process. RAFT copolymerization of PEO45MEMA and MAA enabled to synthesize comb copolymers with low composition distribution and more homogeneous distribution of PEO side chains along the mainchain. Under copolymerization with MAA, PEO45MEMA behaved like typical macromonomer with appropriate steric hindrance while the behavior of PEO5MEMA was similar to that of a low-molecular methacrylate. 相似文献