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1.
Copolymers of allyl glycidyl ether (AGE) with acrylonitrile (AN) have been prepared by bulk polymerization of their monomers with gamma rays. Copolymers thus obtained were characterized by Fourier transform infrared (FTIR), and ultraviolet (UV) spectroscopic techniques. The composition of the copolymers is determined indirectly by FTIR, UV, and directly by elemental analysis. The results obtained by different methods are compared. The reactivity ratios of monomer pairs (AGE + AN) which copolymerized heterogeneously were calculated by using different methods of determination. Among the three experimental methods used for the analysis of compositions and two theoretical methods of computations, the elemental analysis technique and the application of nonlinear least-squares method gave the most reliable reactivity ratios. These are found to be 1.86 and 0.21 for acrylonitrile and allyl glycidyl ether, respectively. © 1996 John Wiley & Sons, Inc.  相似文献   

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Functional aliphatic polycarbonate was synthesized by copolymerization of carbon dioxide and allyl glycidyl ether in the presence of a catalyst system based on ZnEt2 and pyrogallol at a molar ratio of 2 : 1. The polycarbonate obtained was oxidized with m‐chloroperbenzoic acid to give poly(epoxycarbonate). These polymers were degraded in an aqueous buffer of pH 7.4 at 37°C. Hydrolytic degradation was monitored by determination of the weight loss.  相似文献   

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Polymeric surfactants from natural rosin containing a unique tricyclic rigid structure were prepared and their structures were characterized by IR, 1H NMR and GPC. Their surface activities including hydrophile—lipophile balance values (HLB), emulsification properties, foaming properties, critical micelle concentration (CMC) and the minimum surface tension (γCMC) were evaluated. With the increase in ratio of hydrophobic to hydrophilic in polymeric surfactant, the CMC values of the surfactants decreased, and the emulsification and foaming properties of these surfactants increased, and the HLB values of them decreased. This type of polymeric surfactants was used to disperse single-walled carbon nanotubes (SWCNTs) in water, and their dispersal capacities were comparatively determined by UV-visible absorption spectroscopy. Thermogravimetric analysis (TGA) was used to quantify the amount of surfactant attached onto the nanotubes. More intuitive image of their dispersion states were obtained by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The results showed that this type of polymeric surfactants had good dispersion capacity and dispersion stability to SWCNTs in water through strong hydrophobic attraction and weak van der Waals interactions.  相似文献   

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Spontaneous copolymerization of 2-acrylamido-2-methylpropanesulfonic acid with acrylamide and acrylonitrile in concentrated acidic aqueous solutions was studied.  相似文献   

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Coordination-insertion copolymerization of allyl monomers with ethylene was developed by using a palladium/phosphine-sulfonate catalyst. A variety of allyl monomers, including allyl acetate, allyl alcohol, protected allylamines, and allyl halides, were copolymerized with ethylene to form highly linear copolymers that possess in-chain -CH(2)CH(CH(2)FG)- units.  相似文献   

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Associating polymers have been prepared by radical copolymerization in water of acrylamide with a micelleforming cationic polymerizable surfactant. To estimate the locus of initiation, the polymerizations were carried out in the presence of initiators and radical inhibitors of various solubilities (water-soluble or oil-soluble), and the decay of inhibitor concentration has been monitored by electron spin resonance spectroscopy. Conversion–time curves simultaneously determined. The experimental data have been interpreted by taking into account the concentration and lifetime of the different radical species (primary radicals, oligoradicals, inhibitors), their partitioning between the micelles and the aqueous continuous phase, and the dynamics of the micellar system. Analysis of the data provided some insight into the copolymerization mechanism of these micellar systems.  相似文献   

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The interaction of carbon black with an acrylic resin has been investigated by rheology. Two carbon blacks, with similar particle size and surface characteristics but quite different particle morphologies, have been examined. These are somewhat arbitrarily denoted as "spherical" and "fractal" as shown by small-angle neutron scattering (SANS) and ultrasonic spectroscopy studies. In the absence of polymer, stable aqueous dispersions could not be obtained. Stable dispersions could be obtained, however, upon addition of polymer to a level corresponding to a ratio of 50 mg of polymer per 13 m2 (+/- m2) of surface area (i.e., 15 wt% particles). These stable dispersions exhibit flow typical of concentrated dispersions-Newtonian behavior up to some apparent "yield" or critical value, above which pronounced shear thinning is observed. The critical stress increases with increasing polymer concentration. When a significant amount of nonadsorbed polymer is also present, a second Newtonian plateau is superimposed on the shear-thinning behavior. This feature is observed for both particle types but is more pronounced for the fractal particle. When there is little or no nonadsorbed polymer, the viscosity of the fractal particle dispersions is greater than the viscosity of the spherical particle dispersions. At low polymer concentrations, the dispersions are predominantly viscous at low shear stresses. The phase angle decreases significantly over a narrow shear stress range and the rheology tends to more elastic behavior. At higher shear stresses, the dependence on particle morphology is weak.  相似文献   

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Some regularities of radical alternating copolymerization of maleic anhydride with allyl chloroacetate are studied. The formation of donor–acceptor complexes between comonomers with complexing constant Kc = 0.052 L/mol is found using 1H NMR spectroscopy. The kinetic parameters for this copolymerization reaction are found and the quantitative contribution of monomer complexes to chain-growth radical reactions is calculated. It is shown that either a “free-monomer” mechanism (dilute solutions) or a “mixed” mechanism (concentrated solutions) prevails for chain growth during radical copolymerization depending on total monomer concentration. It is found that inhibition of degradative chain transfer in the course of the reaction studied takes place owing to the presence of α-chlorine atom in the allyl chloracetate molecule and formation of charge transfer complex.  相似文献   

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Among the variety of possible structures for polymerizable surfactants, it seems clear that the most interesting should be those with the reactive group located in the hydrophobic part of the molecule. We report here a study based on such a surfactant. Its general formula is A set of surfactants has been produced with m varying from 23 to 48 and n = 6 or 12. The compounds have been characterised by 1H-NMR (nuclear magnetic resonance), size exclusion chromatography, surface tension measurements and turbidimetry. These surfactants have been copolymerized with styrene in emulsion polymerization. The coagulum is rather important, except if m is large enough. Although the incorporation of the surfactant in the latex is rather high. Most of the anchored surfactant remains at the surface and is not too buried inside. The particle size decreases with both the amount of surfactant and the length of its hydrophilic part. The use of these polymerizable surfactants leads to an excellent stability of the latex against the addition of electrolytes, and also against freeze-thawing constraints.  相似文献   

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Copolymerizations of acrylonitrile and isoprene or butadiene were carried out in the presence of a new catalytic system containing Cr(O-tert-Bu)4 and AlEtCl2. It was found that the copolymer compositions have a highly alternating structure, even with varying feed ratios of monomer. The nuclear magnetic resonance spectra of the copolymers obtained with this catalytic system were observed and are discussed in terms of the alternation.  相似文献   

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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   

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Copolymerization of acrylonitrile with methacrylates on a matrix has been examined (using methacrylate of p-cresol-formaldehyde resin). It has been found that the copolymerization proceeds at 70° without an initiator. The reactivity ratios depend on the length of the matrix used. The method of calculating Q and e according to the Alfrey-Price scheme has been discussed for the system under investigation.  相似文献   

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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   

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Radiation induced copolymerizations of electron donating such as allyl phenol (AP) and electron withdrawing such as allyl isothiocyanate (AITC) monomers with styrene (Sty) as a comonomer were studied in order to correlate the electronic behavior with copolymerization yield and molecular weight. The allyl monomers and comonomer were mixed in the same mol ratios under Ar atmosphere and copolymerized by using gamma radiation in various absorbed doses (55, 110, 165 kGy) obtained from a Co-60 source. Poly(AP-co-Sty), and poly(AITC-co-Sty) could have been prepared at all of the absorbed doses. The maximum copolymerization yields were calculated as a 16.35 and 6.52 percent for poly(AP-co-Sty) and poly(AITC-co-Sty), respectively. The molecular weights of poly(AP-co-Sty) copolymers are found to be higher in comparison to those of poly(AITC-co-Sty). Both results indicate that, under the same irradiation conditions, AP is more reactive on styrene than AITC is. Thus, the monomers having electron withdrawing (EW) substituents attached to allyl group may result in better copolymerization yield and molecular weight than those with electron donating (ED) substituents. Thermal stabilities of the poly(AP-co-Sty) copolymers are also higher than those of poly(AITC-co-Sty).  相似文献   

20.
An investigation of the copolymerization of allyl glycidyl ether (AGE) with methyl acrylate (MA) was performed in the presence of benzyl imidazole-1-carbodithioate (BICDT) on the thermal initiation condition. Results showed that the process has good characteristics of living free radical polymerization, i.e. the molecular weight of the obtained polymer increases linearly with monomer conversion, molecular weight distribution is very narrow, and a linear relationship between ln([M]0/[M]) and polymerization time is found. The copolymer structure containing epoxy groups was demonstrated from the 1H nuclear magnetic resonance (1H NMR) spectrum. It was found that the content of AGE in the copolymer increases with the increase in monomer conversion and molar faction of the AGE in the monomer feed. However, the polymerization could slow down when the fraction of AGE increases in the monomer feed. Taking advantage of living polymerization character, functional block copolymers PSt-b-P (MA-co-AGE) were prepared in the presence of PSt RAFT agent. __________ Translated from Journal of Anhui University of Science and Technology, 2006, 26(3): 56–61 [译自: 安徽理工大学学报]  相似文献   

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