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1.
The terpolymerization of acrylonitrile with styrene and 2,3-dibromopropyl acrylate in emulsion and dimethyl formamide solution was investigated. Polymerizations, when stopped at low conversions, yielded terpolymers that showed good agreement between experimental and theoretical copolymerization composition data, calculated from the Alfrey-Goldfinger equation. The relationship between monomer feed and terpolymer compositions is displayed on triangular coordinate graphs proposed by Slocombe. By using a computer program the lines of unique composition and binary azeotropic composition for both systems were established. In the case of emulsion polymerization the azeotropic ternary point was determined at a molar ratio for acrylonitrile/styrene/2,3-dibromopropyl acrylate of 0.27/0.61/0.12. The experimental results of emulsion terpolymerization fit the calculated curves satisfactorily over a wide range of monomer compositions up to high conversions. The influence of 2,3-dibromopropyl acrylate on the thermal and flammability characteristics of the terpolymers is described.  相似文献   

2.
A systematic study of the terpolymerization of butyl acrylate/methyl methacrylate/vinyl acetate (BA/MMA/VAc) was conducted. In this stage of the study, batch emulsion terpolymerizations were performed in a 5 L stainless steel pilot plant reactor. The experiments were designed using a Bayesian (optimal) technique. The polymers produced were characterized for conversion, composition, molecular weight, and particle size. Conversion, terpolymer composition, number- and weight-average molecular weight, and average particle size results are discussed in light of the influence of seven factors and the interaction of these factors. The factors studied include monomer feed composition, initiator concentration, chain transfer agent concentration, impurity concentration, initiator type, emulsifier concentration, and temperature. A “two-stage rate” phenomenon, similar to that occurring in bulk co- and terpolymerization and emulsion copolymerization of acrylic/vinyl acetate systems was observed in the conversion, composition and molecular weight data. Furthermore, an interesting yet often ignored effect of impurities on emulsion polymerization kinetics was explained. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1659–1672, 1997  相似文献   

3.
Acrylonitrile was terpolymerized with styrene and 2,4,6-tribromophenyl acrylate in aqueous emulsion and dimethylformamide solution. Experimental terpolymerization data agreed well with calculations based on the Alfrey–Goldfinger equation. Triangular coordinate graphs show the feed/terpolymer relationships; the lines of unique and binary azeotropic compositions were identified. No points of true azeotropic composition were found but a “pseudo-azeotropic” region was recognized. The experimental data of the emulsion terpolymerization experiment agreed well with the theoretical curves over a wide range of monomer compositions up to high conversions. Incorporation of 2,4,6-tribromophenyl acrylate in the terpolymer decreased the thermal stability but improved the flame retardancy of the terpolymers.  相似文献   

4.
In Part I of this series the reactivity ratios of the comonomer pair methyl acrylate-methyl methacrylate were determined with low-conversion bulk polymerizations. It was shown that the binary reactivity ratios of the systems styrene-methyl acrylate, styrene-methyl methacrylate, and methyl acrylate-methyl methacrylate describe composition drift in low-coversion bulk terpolymerizations with these monomers reasonably well. A computer model was developed to simulate the composition drift in emulsion co- and terpolymerizations. The composition drift in two batch emulsion copolymerization systems (styrene-methyl acrylate and methyl acrylate-methyl methacrylate) and one emulsion terpolymerization system (styrene-methyl acrylate-methyl methacrylate) was investigated both experimentally and with the model. Experimental results were compared with model calculations. The copolymer chemical composition distributions (CCD) were determined with gradient polymer elution chromatography (GPEC®). This technique was also used for the first time to obtain information about the extent of composition drift in emulsion terpolymerizations. Cumulative terpolymer compositions were determined with 3H-NMR as a function of conversion and with this information the three-dimensional CCD was obtained. The composition drift was analyzed with respect to free radical copolymerization kinetics (reactivity ratios) and monomer partitioning. It was shown that in most emulsion copolymerizations the composition drift is mainly determined by the reactivity of the monomers and to a lesser extent by monomer partitioning, except in systems where there is a large difference in water solubility. The model predictions for cumulative terpolymer composition as a function of conversion and the three-dimensional terpolymer CCD showed excellent agreement with the experiments. The GPEC® elution chromatogram of the terpolymer was found to be in accordance with the predicted CCD and the experimentally determined CCD. © 1996 John Wiley & Sons, Inc.  相似文献   

5.
An experimental study shows how the emulsion terpolymerization of lauryl methacrylate (LMA) and methyl methacrylate is influenced by the nature of the third monomer. The third monomer is either glycidyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, or styrene. We report the synthesis of terpolymer particles with an appreciably high content of the very hydrophobic LMA (between 0.2515 and 0.238 molar fraction in the monomer mixture) in 60:40 weight water/ethanol mixture as the continuous phase, poly(vinyl pyrrolidone) as a polymeric steric stabilizer, and potassium peroxodisulfate as the initiator. The emulsion terpolymerization proceeds smoothly without the formation of coagulum and leads to particles with an average diameter clearly below 1 μm. We discuss the overall polymerization behavior regarding conversion–time curves, particle morphology, and glass transition temperature of the terpolymers in dependence of the lyophilicity/lyophobicity of the monomer mixture.  相似文献   

6.
The terpolymerization of ethyl methacrylate (EMA), N‐phenylmaleimide (NPMI), and itaconic acid (IA) was investigated. The terpolymer composition was determined by elemental analysis and 1H NMR spectroscopy. The reactivity ratios of the three binary systems (EMA/NPMI, EMA/IA, and NPMI/IA) were calculated and used for the calculation of the terpolymer composition with the terminal model equations. A comparison between the experimental and theoretical compositions was made. The rate of the terpolymerization process was measured dilatometrically at two total monomer concentrations; this was done to establish the presence of intermolecular interactions between the investigated monomers. The thermal analysis of the obtained terpolymers was performed by thermogravimetric analysis. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3180–3187, 2003  相似文献   

7.
The terpolymerization of acryionitrile, styrene, and pentabromophenyl acrylate in dimethylformamide solution was investigated. Experimental terpolymerization data agreed well with calculations using the Alfrey-Goldfinger equation. The relationship between monomer feed and terpolymer compositions are presented on triangular coordinate graphs, and the lines of unique and the lines of binary azeotropic composition were identified. No point of true ternary azeotropic composition was found but a “pseudoazeotropic” region was identified. The experimental results of the terpolymerization agreed well with the theoretical curves over a wide range of monomer composition up to high conversions. The influence of pentabromophenyl acrylate units on the thermal and flammability characteristics of the terpolymers are described.  相似文献   

8.
A systematic study of the terpolymerization of butyl acrylate/methyl methacrylate/vinyl acetate (BA/MMA/VAc) is being conducted. In this stage of the study, emulsion terpolymerizations were performed in a 5 L stainless steel pilot plant reactor. The experimental trials were of the two-level factorial type and were designed optimally using a Bayesian method. The design procedure allowed us to improve our knowledge about the process using our prior knowledge and our subjective judgement. The polymers produced were characterized for conversion, composition, molecular weight, and particle size. The Bayesian design of experiments is shown to have several advantages over conventional factorial designs. © 1996 John Wiley & Sons, Inc.  相似文献   

9.
氯乙烯/N-苯基马来酰亚胺共聚物组成控制和优化   总被引:7,自引:0,他引:7  
研究了氯乙烯 /N 苯基马来酰亚胺 (VC/PMI)共聚物组成随转化率的变化 ,体系中共聚物的累积组成偏差小于 0 0 5或 0 1的单体配比范围很小 ,采用加入第三单体丙烯腈 (AN)的方法进行改善 ,并以PMI在共聚物中的累积组成偏差作为控制参数 ,得到了PMI在共聚物中的累积组成偏差小于 0 0 5和 0 1的VC/PMIlAN较优的配比范围 .结合悬浮聚合工艺的特点 ,确定了VC/PMI/AN悬浮共聚的最佳单体配比范围为f1=0 72~ 0 84 ,f2 =0 0 2~ 0 0 4 ,f3 =0 1 2~ 0 2 4 .  相似文献   

10.
Abstract

Probability theory has been used to derive equations for the terminal model for free radical terpolymerization, showing how the polymer composition and triad fractions are related to the reactivity ratios and monomer composition. These relationships have been used to analyze the monomer-polymer composition data for the acrylonitrile-styrene-2,4,6-tri-bromophenyl acrylate system using a nonlinear least-squares method. The “best values” of the reactivity ratios which describe the polymerization have been used to calculate the triad fractions for each monomer.  相似文献   

11.
Cationic copolymerization of 1,3,5-trioxane with methyl 10,11-epoxyundecanoate or methyl 7,8-epoxyoctanoate and terpolymerization with 1,3-dioxolane was successfully carried out. Co-and terpolymerization of 1,3,5-trioxane with 4-(1-carbomethoxynonyl)-1,3-dioxolane was also achieved. Feed compositions of the functional comonomers were varied from 5 to 40 mol %; in all cases the isolated copolymers contained less than 5% of the functional mer units. The composition of the copolymers showed that the methyl ω-epoxyalkanoates were much less reactive than 1,3,5-trioxane. A similar trend was observed with the functional dioxolane monomer, although significantly shorter induction periods were observed in comparison with the epoxy/trioxane copolymerizations. The oxymethylene copolymers and terpolymers were characterized primarily by their infrared spectra; however, the thermal and base stabilities of selected copolymers were also determined.  相似文献   

12.
Abstract

The terpolymerization of butadiene, acrylonitrile, and methacrylic acid in emulsion, using potassium persulfate as initiator and sodium dioctylsulphosuccinate as emulsifier, was investigated. For the binary system butadiene (M1) and methacrylic acid (M2), the following monomer reactivity ratios were determined: r12 = 0.18 ± 0.05 and r21 = 0.52 ± 0.09. When polymerizations were stopped at low conversions they gave terpolymers which show good agreement between experimental and theoretical copolymerization composition data, calculated from the Alfrey-Goldfinger equation. The relationships between monomer feed and terpolymer compositions are presented on triangular coordinate graphs as proposed by Slocombe. By using a computer program, the lines of unique composition and the lines of binary azeotropic composition were established. No point of true azeotropic composition was found, but a “pseudo-azeotropic” region was recognized. The influence of composition on glass transition temperature and thermal characteristics of the terpolymers is described.  相似文献   

13.
In this study, polymers of the MMA/Styrene/BMA three‐component system were synthesized through either soapless semibatch emulsion copolymerization or soapless batch emulsion copolymerization technique. The optimal monomer feed flow rate was determined from the interphase partition laws, monomer reactivity ratios, and three or four times of iterative experimental procedures through semibatch emulsion copolymerization. As a result, the instantaneous composition of polymers could also be effectively controlled to get the desired final products. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3253–3269, 2000  相似文献   

14.
The terpolymerization composition equation has been modified to eliminate the consideration of interactions between monomers 2 and 3 when they are present in low concentration in the feed mixture relative to monomer 1. Terpolymers with a wide variety of comonomers and compositions have been synthesized and used to demonstrate that a simplified terpolymerization equation accurately predicts terpolymer composition.  相似文献   

15.
The general concept for nitroxide‐mediated radical terpolymerization is advanced. This concept is based on activation‐deactivation equilibria for terminal polymer‐nitroxide adducts. Depending on monomer activity and the stability of terminal nitroxide adducts, terpolymerization can be equilibrium living, quasi‐equilibrium (gradient) living, decaying living, decaying gradient, or non‐living. Expressions for the effective activation‐deactivation equilibrium constant, Kef, and the rate of terpolymerization are derived from theoretical speculations on equilibrium living and decaying living terpolymerization. For quasi‐equilibrium living terpolymerization, various types of gradient terpolymers are predicted. When activity of the active monomer M1 is, at least, one order of magnitude different from that of the two other monomers, the effective constant Kef is shown to approach K1 of the most active monomer. Experimental kinetic and equilibrium constants agree with the advanced concept for the equilibrium living terpolymerization of styrene with methyl methacrylate, and acrylonitrile in the presence of nitroxide SG1, as well as for decaying living terpolymerization in the same system in the presence of nitroxide TEMPO.

  相似文献   


16.
An optimal addition profile for the preparation of a chemically homogeneous emulsion terpolymer of styrene, methyl methacrylate, and methyl acrylate was determined using a recently developed model for describing composition drift in emulsion co- and terpolymerizations. TRISEPS, described in Part I of this series. The model uses recently published simplified equations to describe monomer partitioning and the terminal model for describing terpolymer composition. The optimal addition rate profile was determined from the calculated optimal addition profile with a purely empirical and iterative method. With gradient polymer elution chromatography (GPEC®) the homogeneity and/or heterogeneity of the terpolymers prepared in the iterative series of experiments could be determined and compared to the heterogeneity of the corresponding batch terpolymer described in Part I. It was shown that a homogeneous terpolymer could be obtained indicating that the simplified equations for monomer partitioning and the terminal model for terpolymer composition describe the system adequately. It was also shown that GPEC® was useful in the determination of the optimal addition rate profile. © 1996 John Wiley & Sons, Inc.  相似文献   

17.
The radical terpolymerization of the donor-acceptor-donor monomer system, phenanthrene (P)—maleic anhydride (M)—trans-stilbene (S), was studied. These monomers are known to be nonhomopolymerizable. The terpolymerization was carried out in p-dioxane and/or toluene at 70°C in the presence of benzoyl peroxide used as the initiator. P and S were found to form charge transfer complexes (CTC) with M in p-dioxane at 35°C. The results obtained are discussed in terms of the free monomer and complex propagation models. It is shown that terpolymerization is carried out at a stage close to binary copolymerization of two complexomers. The reactivity ratio of P … M and S … M complexes was estimated by the Kelen-Tüdös method. Absorbance ratios at 1770 cm?1 (vC=0 of anhydride group), 764 cm?1CH in monosubstituted benzene of S), and 820 cm?1CH in disubstituted benzene of P) as a function of terpolymer composition were established. P—M—S terpolymers are shown to have high thermal stabilities. © 1995 John Wiley & Sons, Inc.  相似文献   

18.
A model for evaluating instantaneous degree of polymerization distribution and the chain composition distribution of copolymers produced in emulsion is developed. The approach adopted is based on the mathematics of Markov processes and represents an extension of the one developed for homopolymers in Part I. As in the homopolymer case, the main aspect of the theoretical treatment is the definition of the proper one step transition probability matrix through the so called subprocess-main process procedure. The model accounts for monomolecular and bimolecular termination (both by combination and disproportionation) and, in principle, it can be applied to any number of reacting monomer species as well as to any number of active chains per particle. However, only the 0–1–2 and 0–1–2–3 emulsion copolymerization systems are discussed in detail. In the case of the chain composition distribution, the model allows the calculation of its moments only, through the method of the Generating Function associated with the probability density function. The expression obtained for the instantaneous probability density functions, as well as for the corresponding cumulative distributions, are all in explicit form and involve only algebraic operations among matrices. Efficient numerical procedure for their application are reported in the Appendix. Illustrative calculations are reported for a 0–1–2–3 copolymerization system, simulating the copolymer styrene–methylmethacrylate. The effect of the various termination mechanisms on the distribution of degrees of polymerization and on the first two moments of the chain composition distribution is discussed in detail. Finally, the three dimensional overall distribution function of both chain length and composition is shown under the assumption of Gaussian type chain composition distribution.  相似文献   

19.
The free radical copolymerization and terpolymerization of acrylic monomers with olefins in the presence of Lewis acid complexing agent for the acrylic monomer has been investigated. The course of the polyreaction is in agreement with the features of a radical chain growth reaction, and the polymer properties can be varied by changing the composition of the reaction mixture and the reaction conditions. The alternating copolymers are usually amorphous materials, and only the alternating ethylene/acrylonitrile copolymer can be obtained as a material of relatively high crystallinity. The degree of crystallinity can be varied through terpolymerization of complexed acrylonitrile with ethylene/propylene comonomers. The basic features of the polyreaction and the polymer structures as well as some of the physical and material properties of the copolymers have been studied.  相似文献   

20.
Previous work from this laboratory has shown that certain 1,4-dienes which readily undergo cyclocopolymerization with certain alkenes also form charge-transfer complexes with the same alkenes. The results observed and the proposed cyclocopolymerization mechanism are consistent with participation of the charge-transfer complex as a distinct species in the copolymerization. It was the purpose of this investigation to determine whether there was a dilution effect on the relative reactivities of the monomers in support of the charge-transfer participation concept, and whether the results of a suitable terpolymerization study would also support this postulate. In the divinyl ether–fumaronitrile system, the maximum rate of copolymerization occurred at a monomer feed ratio of 1:2 and the composition of the copolymer was also 1:2 at a total monomer concentration of 3 mole/l. However, when the concentration was progressively lowered to 0.5 mole/l. at the same monomer feed ratio, the fumaronitrile content of the copolymer decreased in a linear manner. In a series of terpolymerization experiments with the divinyl ether–maleic anhydride–acrylonitrile system, it was shown that the divinyl ether–maleic anhydride ratio in the terpolymer was always less than 1:1 and had an upper limit of 1:2, regardless of the feed ratio of the termonomers. These results are consistent with the participation of the charge-transfer complex of divinyl ether and maleic anhydride in a copolymerization process with either maleic anhydride or acrylonitrile as the comonomer.  相似文献   

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