Radiation copolymerization of vinyl acetate with the diethyl esters of maleic and fumaric acids

The radiation-induced copolymerization of vinyl acetate with diethyl maleate and with diethyl fumarate was investigated in the temperature range from ?40 to 90°C over a wide range of comonomer compositions. Both the rates of copolymerization and the molecular weights of the resulting copolymers were found to depend strongly on the initial comonomer compositions. The apparent activation energy was found to change at 13°C with an increase in temperature from a value of 1.76 kcal/mole to a value of 4.31 kcal/mole in the copolymerization with diethyl maleate, while in the case of the copolymerization with diethyl fumarate the apparent activation energy changed at 21°C from a value of 1.76 kcal/mole to a value of 5.98 kcal/mole. Scavenger studies indicate that a free-radical mechanism prevails over the entire temperature range investigated in the case of both copolymerizations.     

Copolymerization of styrene and diethyl fumarate with zinc bromide. V. Electroinitiated copolymerization at high current strengths

The electroinitiated copolymerization of styrene and diethyl fumarate in methanol solvent with zinc bromide as electrolyte has been investigated at high current strengths (200–500 mA). Unlike the copolymerization behavior observed at lower current strengths (< 200 mA), it is found that the cathodically produced copolymers deviate from a 1:1 composition and show a significant deficiency in styrene. The copolymer products can be separated into two well-defined fractions: a toluene-soluble fraction (normal copolymer) and a toluene-insoluble one (styrene-deficient copolymer). These deviations in copolymer composition from a 1:1 monomer ratio are attributed to the occurrence of cathodically induced electroreductive hydrolysis side reactions with diethyl fumarate leading to the formation of carboxylate or acid salt species. Reaction of these hydrolyzed species with diethyl fumarate results in the formation of fumarate-rich copolymers.     

Calorimetric investigation of polymerization reactions. IV. Curing reaction of polyester fumarate with styrene

The curing reaction of polyester fumarate with styrene was investigated with a differential scanning calorimeter (DSC) operated isothermally. The change in rate of cure was followed over the whole range of conversion. The rate of cure is accelerated by the gel effect to about ten to fifty times the rate of model copolymerization of diethyl fumarate with styrene. This autoacceleration is much enhanced for systems with higher crosslinking densities and at lower temperatures. The results confirm that both termination and propagation steps of the curing reaction are controlled by diffusion of polymeric segments and monomer molecules over almost the whole range of conversion. The final extent of conversion is short of completion for isothermal cure and even for postcure of polyester fumarate with styrene because of crosslink formation. The final conversion of isothermal cure decreases with increasing crosslinking density and shows a maximum with increasing reaction temperature. This temperature dependency of the final conversion is caused by the difference in the activation energies for two propagation rate constants k_pf and k_ps, which were evaluated to be 7–10 and 5–8 kcal/mole, respectively, for the intermediate stage of the curing reaction.     

Reactive oligomers. I. Preparation and polymerization of ethylene glycol bis(methyl fumarate)

Ethylene glycol bis(methyl fumarate) (EGBMF) was prepared as a new type of divinyl compound and reactive oligomer: a needle crystal, m.p. 104.5°C. Homopolymerization of EGBMF was carried out in dioxane with 0.1 mol/L AIBN at [M] = 1 mol/L and 60°C; the rate of polymerization was estimated to be 4.44 × 10^?6 mol/L s in a good agreement with diethyl fumarate (DEF). The cyclization constant K_c was obtained as 1.64 mol/L, being rather low compared with diallyl oxalate which is 1,9-diene having two ester groups analogous to EGBMF. Gelatin occurred at about 35% conversion. Finally, the copolymerization of EGBMF (M₁) with diallyl phthalate (DAP) (M₂) is tentatively explored with the intention of the improvement of allyl resins in mechanical properties; remarkable rate enhancement was observed for copolymerization. The monomer reactivity ratios were estimated to be r₁ = 0.96 and r₂ = 0.025, the r₁ value being reduced compared with the DEF-DAP copolymerization system. These results are discussed from the standpoint of steric effect on the polymerization of fumarate as an internal olefin.     

Vinylhydroquinone. V. Tri-n-butylborane-initiated copolymerization of maleic anhydride and redox property of copolymers

Tri-n-butylborane (TBB) was found to be capable of initiating the copolymerization of vinylhydroquinone (VHQ) with maleic anhydride (MAn) and diethyl fumarate (DEF) in cyclohexanone at 30°C under nitrogen. Redox potentials of the VHQ–MAn copolymer obtained were examined. These results, along with spectroscopic data, indicate that the copolymers are of a highly alternating character.     

Synthesis and Characterization of Fumarate Copolyesters for Use in Bioresorbable Bone Cement Compositions

Unsaturated amorphous copolyesters of varied composition were prepared by transesterification copolymerization of diethyl fumarate, and two diols, 1,2‐propanediol and 2‐methyl‐1,3‐propanediol. The copolyesters were characterized by IR, ¹H‐ and ¹³C‐NMR, GPC, DSC, and TGA. The glass transition is changing with composition from 0°C to 19°C as the content of 1,2‐propanediol residue in the copolyester increases. The copolyester structure and composition have an impact on the compressive strength and hydrolytic stability of the composites prepared by crosslinking the fumarate double bonds with N‐vinyl pyrrolidone in the presence of inorganic filler, calcium sulfate dihydrate, with the addition of a radical initiator, benzoyl peroxide, at ambient temperatures.     

Studies of the polymerization of diallyl compounds. XXXVII. Copolymerizations of diallyl phthalate with dialkyl fumarates

Diallyl phthalate (DAP) was copolymerized with dialkyl fumarates, including diethyl fumarate (DEF), di-n-butyl fumarate (DBF), and di-n-octyl fumarate (DOF) by using 2,2′-azobisisobutyronitrile as an initiator at 60°C. Both rate and degree of copolymerization were quite enhanced compared with the homopolymerization of DAP and the maximum rate was found at the molar ratio of 1:1 in the monomer feed. The cyclization of DAP was almost exclusively suppressed in the Copolymerization. Gelation was promoted from 25% of the gel-point conversion for the DAP homopolymerization to 9% of the minimum one observed. Copolymerizability of DAP (M₁) with dialkyl fumarates (M₂) was quite high, with the following monomer reactivity ratios M₂, r₁, r₂: DEF, 0.01, 1.25; DBF, 0.02, 1.01; DOF, 0.02, 0.96. These results are discussed in mechanistic detail.     

Polymerization of allyl esters of unsaturated acids. VII. Copolymerization of methyl allyl maleate and fumarate with styrene

Radical copolymerizations of methyl allyl maleate (MAM) and methyl allyl fumarate (MAF) with styrene (St) are carried out in bulk using AIBN as an initiator at 60°C, and their copolymerization behaviors are compared in detail. The different rate features are observed with each other; thus in the MAF-St copolymerization the rate was quite enhanced and, also, the maximum rate was found at the molar ratio of 1:1 in the monomer feed, whereas no maximum phenomenon of the rate was apparent for the MAM—St copolymerization. The copolymerizability of MAF with St was quite high, whereas that of MAM was very poor. The cyclization of MAM or MAF was hindered by the highly reactive St monomer. These results are discussed in terms of the formation of the charge—transfer complex between MAF and St and, furthermore, the cyclocopolymerization kinetics involving the 17 elementary reactions as the propagation reactions.     

Synthesis and Characterization of Diethyl Fumarate‐1,4‐Cyclohexanedimethanol Polyesters for Use in Bioresorbable Bone Cement Composites

Unsaturated polyesters are prepared by transesterification polymerization of diethyl fumarate and 1,4‐cyclohexanedimethanol. The structure of the polyesters was characterized by FT‐IR and ¹H‐ and ¹³C‐NMR spectroscopy. Semicrystalline morphology of the polymers is suggested by DSC analysis with T_g at 21°C and melting at 140°C. The thermogravimetric analysis indicated that the onset of degradation takes place at 300°C. The polyester's structure has significant impact on the properties of the composites prepared by crosslinking the fumarate double bonds with N‐vinyl pyrrolidone in the presence of an inorganic filler, calcium sulfate dihydrate, with the addition of a radical initiator, benzoyl peroxide, at ambient temperatures. The compressive strength and hydrolytic stability of the cement compositions was correlated with structure of the polyesters.     

Studies on copolymers of vinyl chloride with diethyl fumarate,isobutylene and vinyl bromide,as models of PVC with chain irregularities—II The influence of copolymerization on the tacticity of PVC sequences: The influence f copolymerization on the tacticity of PVC sequences

Copolymers of vinyl chloride (> 90%) with diethyl fumarate, isobutylene and vinyl bromide, prepared at temperatures between +25 and ?30°, were used to determine the influence of the copolymerization on the tacticity of polyvinyl chloride sequences in the copolymers. The tacticity appeared to decrease in proportion as the comonomer content increases, this effect being different for the three kinds of copolymers. The results are discussed by taking into consideration the comonomer volume, the Arrhenius plots and the sequence distribution in copolymers after calculation of the number of alternances per 100 monomer units.     

Copolymerization of styrene and diethyl fumarate with ZnBr2. IV. Comparison between photoinitiation and electroinitiation

A comparative analysis of photoinitiation and electroinitiation can help elucidate initiation processes in donor-acceptor charge-transfer copolymerization. The technique has been applied to the zinc bromide-catalyzed copolymerization of styrene and diethyl fumarate in methanol. The photocopolymer product was analyzed by GPC, NMR, and elemental analysis. The results showed that 1:1 copolymers were formed initially, but changes occurred in both the kinetics and products after the early stages of the reaction. Significant correlations found between the two initiation methods included the initial kinetic order with respect to the initiating process and the effect on product yield of equivalent increases in total initiation energy. The limiting value of zinc bromide for both initiation methods was found to be the same. The data obtained support the contention that the copolymerization proceeds through a donor–acceptor process and that photoactivation of the preformed complex, inducing electron transfer, is a likely initiation process.     

Enzymatic syntheses of unsaturated polyesters based on isosorbide and isomannide

The search for materials produced from renewable sources aiming at the substitution of petroleum‐based derivates is an area of intense investigation. In this work, the enzymatic copolymerization of isosorbide or isomannide with diethyl adipate and fractions of different unsaturated diesters (diethyl itaconate, diethyl fumarate, diethyl glutaconate, and diethyl hydromuconate) were examined using CAL‐B as catalyst. The polyesters prepared using one‐step syntheses were characterized by SEC, NMR, and MALDI‐TOF MS. In addition, syntheses with linear diols were carried out in bulk to evaluate the reactivity of cyclic diols in producing unsaturated polyesters using enzymatic catalysis, as well as to evaluate the occurrence of addition side reactions on the double bonds. Isosorbide and isomannide yielded unsaturated polymers with values in the order of 4,000‐16,000 when fumarate or glutaconate esters were added in 5 mol % ratio against adipate. In all cases MALDI‐TOF confirmed the presence of unsaturated units. Although these polyesters have unreacted double bonds they are prone to crosslinking and ready to further functionalization, like anchoring bioactive molecules. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3881–3891     

Kinetics of Radical Copolymerization. XV. Absolute Rate Constants in the Copolymerization System Styrene-Ethyl Acrylate-Benzene

Abstract

With the use of rate data of the system St-EA-AIBN-Bz-50°C measured earlier, the parameters of the rate equation derived in terms of the hot radical theory were determined. The reason for the reevaluation of experimental data was that the absolute values of propagation and termination rate constants could be determined in the homopolymerization of both monomers with the improved rotating sector method elaborated for nonsteady-state kinetic investigations. This enabled us to determine the rate constants of the elementary reactions and deactivation parameters (γ₁₂ and γ₂₁) of the copolymerization. The rate data calculated with the new parameter set are in good agreement with the measured ones, proving the applicability of the hot radical theory. The results are represented by a steric coordination system in order to call attention to the importance of the simultaneous study of composition-and dilution-dependence in copolymerization.     

二乙基二烯丙基氯化铵均聚及其与丙烯酰胺或丙烯酸共聚动力学研究

采用膨胀计法研究了以过硫酸铵为引发剂,二乙基二烯丙基氯化铵(DEDAAC)在水溶液中的均聚及其与丙烯酰胺(AM)和丙烯酸(AA)共聚动力学,测定了相应的聚合表观活化能;采用元素分析法测定了DEDAAC分别与AM和AA在低转化率下共聚物的组成,并采用氯离子选择性电极法测定了DEDAAC-AM共聚物中的氯离子含量,按Kelen-Tudos方法求得了相应的竞聚率.结果表明,DEDAAC均聚速率方程为RP=k[M]0.99[I]0.76,表观活化能Ea=77.00kJ/mol,说明链终止为单基终止和双基终止并存,引发过程与单体浓度无关;DEDAAC与AM在摩尔比为4∶1时,共聚动力学方程为RP=[M]2.53[I]0.90,表观活化能Ea=67.06kJ/mol,单体竞聚率为rDE=0.31±0.02、rAM=5.27±0.53;DEDAAC与AA在摩尔比为4∶1时,共聚动力学方程为RP=k[M]2.94[I]0.83,表观活化能Ea=70.07kJ/mol,竞聚率为rDE=0.28±0.03、rAA=5.15±0.28;DEDAAC与AM和AA等共聚为非理想共聚,得到的产物均为无规共聚物.     

Free‐radical copolymerization of styrene with butyl acrylate. II. Elemental kinetic copolymerization step predictions from homopolymerization data

The free‐radical copolymerization of styrene and butyl acrylate has been carried out in benzene at 50 °C. The lumped k _p/k parameter (where k _p and k _t are the average copolymerization propagation and termination rate constants, respectively) has been determined. Applying the implicit penultimate unit model for the overall copolymerization propagation rate coefficient and the terminal unit effect for the overall copolymerization termination rate coefficient and using the homopolymerization kinetic coefficients, we have found good qualitative agreement between the experimental and theoretical k _p/k values. The variation of the copolymerization rate in solution with respect to the values previously found in bulk has been ascribed to a chain length effect on the copolymerization termination rate coefficient. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 130–136, 2004     

Radiation-induced copolymerization of formaldehyde and styrene

The radiation-induced copolymerization of styrene with liquid formaldehyde in bulk and in solution has been studied at low temperatures. In bulk and in methylene chloride solution copolymerization took place, whereas in diethyl ether solution only homopolymerization of the formaldehyde was found. At ?78°C., in bulk and in methylene chloride solution, no evidence of polystyrene blocks could be found, whereas at ?30°C. in bulk about 30% of the styrene content of the copolymer was in the form of high molecular weight blocks. The rate of copolymerization in methylene chloride solution was found to be first-order with respect to dose rate and third-order with respect to formaldehyde concentration similar to results reported for formaldehyde in toluene solution. The thermal stabilities of the copolymers were found to be intermediate between those of pure polyoxymethylene and commercially stabilized polymers. Since the latter were of higher molecular weight and contain added stabilizers, the increased thermal stabilities of the copolymers were considered to be particularly significant.     

Termination Rates in Free Radical Copolymerizations

The rates of free radical copolymerizations at given rates of initiation can be analyzed ideally in terms of monomer feed concentrations and reactivity ratios, propagation rate constants for homopolymerizations of the particular monomers, and an overall rate constant for termination during copolymerization. This model, which is due to Atherton and North, can account for the effects of initiator concentration and viscosity of the polymerization medium on copolymerization rates.

This article reports an empirical formulation for the overall termination rate constant in terms of monomer concentrations and reactivity ratios and a cross-termination factor. The new model accounts for experimental data in the styrene-methyl methacrylate system in which polarity differences between unlike radicals may result in enhanced termination rates. It also predicts observed copolymerization rates of methyl methacrylate-vinyl acetate and styrene-α-methylstyrene mixtures in which polarity effects are absent. The cross-termination factor may be approximated from reactivity ratio data for predictive purposes.     

Studies on copolymers of vinyl chloride with diethyl fumarate,isobutylene and vinyl bromide as PVC models with chain irregularities—III The influence of the tacticity and of the copolymer composition on the thermal degradation: The influence of the tacticity and of the copolymer composition on the thermal degradation

The thermal degradation kinetics of pairs of vinyl chloride copolymers with diethyl fumarate, isobutylene and vinyl bromide, having the same composition but different tacticity, were followed by conductivity measurements. From the results for degradation up to 0·3% and up to 10%, it follows that syndiotactic sequences in PVC give rise to high degradation rates in agreement with results of previous work on homopolymers of vinyl chloride. On the basis of kinetic aspects as well as u.v.- visible spectra of degraded samples, the influence of tacticity on the thermal degradation of copolymers is discussed. This effect is compared to that of weak points introduced in the PVC chain by means of copolymerization.     

Towards Green Routes for Polymer Synthesis: Polymerization of Cyclodextrin Host‐Guest Complexed Diethyl Fumarate and Copolymerization with Complexed Styrene in Homogenous Aqueous Solution

Summary: The radical homo‐ and copolymerization of styrene ( 1 ) and diethyl fumarate (DEF, 2 ) in the presence of methylated β‐cyclodextrin (β‐CD) in water is described. It has been shown for the first time that homopolymerization of CD‐complexed DEF and its copolymerization with CD‐complexed styrene occur readily in aqueous solution. In the absence of CD, or in organic solvents, the homopolymerization of DEF is strongly retarded.

     

Radical polymerization of isopropyl tert-butyl fumarate and maleate,and characterization of the resulting polymers

Radical polymerization of isopropyl tert-butyl fumarate (iPtBF) and monomer-isomerization radical polymerization of isopropyl tert-butyl maleate (iPtBM) were investigated with 2,2′-azobisisobutyronitrile as initiator in the presence and absence of morpholine (Mor) as isomerization catalyst. It was found that iPtBF gave high molecular weight polymers in high yield as previously observed for diisopropyl fumarate (DiPF) and di-tert-butyl fumarate (DtBF). It was confirmed that iPtBF produced by in situ monomer isomerization of iPtBM homopolymerized to give a polymer. Radical copolymerization of iPtBM with styrene in the presence and absence of Mor was also performed and monomer reactivity ratios obtained were compared. From the kinetic study of the isomerization of iPtBM, it was revealed that the isomerization rate showed first-order dependence on the concentration of iPtBM and Mor, and that the apparent activation energy was 29.4 kJ/mol. On pyrolysis of the poly(iPtBF) at 180°C, isobutene and isopropanol were eliminated rapidly to yield polymer containing carboxyl groups and anhydrides. The pyrolytic behavior was different from that of a copolymer of DiPF with DtBF.