Studies of the polymerization of diallyl compounds. XII. Cyclocopolymerization of dimethallyl phthalate with vinyl acetate

Dimethallyl phthalate was copolymerized with vinyl acetate at 60°C with the use of benzoyl peroxide as an initiator. The rate and degree of copolymerization increased with an increase in the mole fraction of vinyl acetate. The residual unsaturation of the copolymer was nearly constant, regardless of the feed molar ratio. The monomer reactivity ratios (MRR) were obtained on the basis of the copolymer composition equation in which the intramolecular cyclization reaction was considered: γ₁ = 1.08 (MRR of the uncyclized radical), γ₂ = 0.99 (MRR of vinyl acetate radical), γ_c = 0.73 (MRR of the cyclized radical). The difference between γ₁ and γ_c is discussed.     

Reactivity ratios and microstructure determination of vinyl acetate–alkyl acrylate copolymers by NMR spectroscopy

(Vinyl acetate)/(ethyl acrylate) (V/E) and (vinyl acetate)/(butyl acrylate) (V/B) copolymers were prepared by free radical solution polymerization. ¹H-NMR spectra of copolymers were used for calculation of copolymer composition. The copolymer composition data were used for determining reactivity ratios for the copolymerization of vinyl acetate with ethyl acrylate and butyl acrylate by Kelen-Tudos (KT) and nonlinear Error in Variables methods (EVM). The reactivity ratios obtained are r_v = 0.03 ± 0.03, r_E = 4.68 ± 1.70 (KT method); r_v = 0.03 ± 0.01, r_E = 4.60 ± 0.65 (EV method) for (V/E) copolymers and r_v ? 0.03 ± 0.01, r_B ? 6.67 ± 2.17 (KT method); r_v = 0.03 ± 0.01, r_B = 7.43 ± 0.71 (EV method) for (V/B) copolymers. Microstructure was obtained in terms of the distribution of V- and E-centered triads and V- and B-centered triads for (V/E) and (V/B) copolymers respectively. Homonuclear ¹H 2D-COSY NMR spectra were also recorded to ascertain the existence of coupling between protons in (V/E) as well as (V/B) copolymers. © 1995 John Wiley & Sons, Inc.     

Intramolecular excimer formation in macromolecules. I. Energy migration and excimer formation in copolymers exhibiting nearest-neighbor excimer interactions

Energy migration and intramolecular excimer formation have been studied in a series of copolymers comprising 1-vinylnaphthalene, 2-vinylnaphthalene, and styrene with methyl methacrylate. The technique of fluorescence depolarization was used to characterize energy migration in glassy solutions of the copolymers. The extent of energy migration in these copolymers is determined by the mean sequence length of aromatic species l?_a. Assuming that excimer formation occurs as a result of nearest-neighbor interactions, the concentration of excimer sites in the macromolecule will be proportional to the fraction of links between aromatic species f_aa. It is proposed that these sites are populated via energy migration from the site of absorption. Proportionality between the ratio of excimer to monomer emission intensities and the function l?_a·f_aa was predicted. Good agreement with this relationship was obtained in each of the copolymer systems studied. Reactivity ratios of methyl methacrylate (r_m) in copolymerization at 70°C with the aromatic monomers (r_a) were determined as: 1-vinylnaphthalene—r_m = 0.43, r_a = 1.71: 2-vinylnaphthalene—r_m = 0.37, r_a = 4.46; styrene-r_m = 0.45, r_a = 0.58.     

Donor-acceptor complexes in copolymerization. L. Preparation and microstructure of chlorine-containing alternating conjugated diene–acceptor monomer copolymers

Neighboring monomer units cause significant shifts in the infrared absorption peaks attributed to cis- and trans-1,4 units in conjugated diene-acceptor monomer copolymers. Conjugated diene-maleic anhydride alternating copolymers apparently have a predominantly cis-1,4-structure, while alternating diene-SO₂ copolymers have a predominantly trans-1,4 structure. Alternating copolymers of butadiene, isoprene, and pentadiene-1,3 with α-chloroacrylonitrile and methyl α-chloroacrylate, prepared in the presence of Et_1.5AlCl_1.5(EASC), have trans-1,4 unsaturation. Alternating copolymers of chloroprene with acrylonitrile, methyl acrylate, methyl methacrylate, α-chloroacrylonitrile, and methyl α-chloroacrylate prepared in the presence of EASC-VOCl₃ have trans-1,4 configuration. The reaction between chloroprene and acrylonitrile in the presence of AlCl₃ yields the cyclic Diel-Alder adduct in the dark and the alternating copolymer under ultraviolet irradiation. The equimolar, presumably alternating, copolymers of chloroprene with methyl acrylate and methyl methacrylate undergo cyclization at 205°C to a far lesser extent than theoretically calculated, to yield five and seven-membered lactones. The polymerization of chloroprene in the presence of EASC and acetonitrile yields a radical homopolymer with trans-1,4 unsaturation.     

Amphiphilic graft copolymers with poly(oxyethylene) side chains: Synthesis via phthalimidoacrylate prepolymers

Amphiphilic graft copolymers of definite composition were obtained by grafting of amino-functionalized poly(oxyethylene) monoether (MPEO–NH₂) of M?_n = 750, 2000, and 5000 onto phthalimidoacrylate (PIA) homopolymer or its copolymer with styrene (St). The radical co-polymerization of PIA and phthalimidomethacrylate (PIMA) with St was studied in dimeth-ylformamide (DMF) at 60°C. The copolymer composition curves and the monomer reactivity ratios showed a high tendency of PIA to alternating copolymerization with St (r₁r₂ = 0.006). Hydrogen bonding between the functional groups leads to significant spectral modifications. The micellization of the graft copolymers was studied by GPC in aqueous-methanolic eluent. The aggregation behavior of the graft copolymers depended on their composition and chromato-graphic separation lead to the copolymers fractionation. © 1995 John Wiley & Sons, Inc.     

Viscosity behavior of polyelectrolyte copolymers containing sulfonate groups in mixed organic solvents

Copolymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS, monomer 1) with 2-hydropropyl methacrylate (HPM, monomer 2) was conducted in ethylene glycol/water (1 : 1 in weight) at 70°C. The reactivity ratios estimated from the copolymer composition at low conversion are r₁ = 2.31 ± 0.25 and r₂ = 11.70 ± 1.05. The azeotropic composition was found at the monomer mole ratio AMPS/HPM equal to 8/2. Viscosity of these copolymers was measured in dimethyl sulfoxide (DMSO) and DMSO/tetrahydrofuran (THF) mixed solvent at 25 ± 0.05°C. Polyelectrolyte behavior was observed for all the copolymers, even in the mixed solvent containing 65 wt % of THF. The reduced viscosity at constant polymer concentration decreased with increasing THF content in the mixed solvent. The copolymers having AMPS repeat units more than 42 mol % precipitated in the mixed solvent when the THF was beyond 68 wt %. The viscosity reduction and precipitation in the copolymer solutions with increasing THF can be attributed to the dipole–dipole attraction between ion-pairs formed in less-polar medium. This is helpful in understanding the volume phase transition in highly charged hydrogels caused by mixing solvents. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 1433–1438, 1997     

Copolymerization of 4‐Propanoylphenyl Acrylate with Methyl Methacrylate: Synthesis,Characterization and Reactivity Ratios

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 (M_w and M_n) 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.     

Influence of the reaction medium on the composition and the microstructure of styrene–acrylic acid copolymers

Two series of acrylic acid-styrene copolymers of various composition have been prepared in benzene and dimethylformamide in order to study their sequence distribution by using ¹³C NMR spectroscopy. The reactivity ratios in benzene were r_A = 0.13, r_A = 0.30 and in dimethylformamide r_A = 0.05, r_S = 1.60. Copolymers with the same overall composition but prepared in different media display marked differences in sequence distribution, the copolymers obtained in dimethylformamide always having longer sequences. For the series of copolymers prepared in dimethylformamide, the experimental percentages of acrylic acid-centered triads (SAS, SAA, AAA) disagree with the values calculated from the monomer reactivity ratios.     

Esterolytic activity of imidazole-containing polymers. Synthesis and characterization of copoly[1-alkyl-4- or 5-vinylimidazole/4(5)-vinylimidazole] and its catalytic activity in the hydrolysis of p-nitrophenyl acetate

The water-soluble monomers, 1-methyl-4-vinylimidazole, 1-methyl-5-vinylimidazole, 1-ethyl-5-vinylimidazole, and 1-propyl-5-vinylimidazole have been synthesized, polymerized, and copolymerized with 4(5)-vinylimidazole. The copolymers were characterized by ¹⁴C-labeling, NMR, pK_a determination and viscosity measurements. The monomer reactivity ratios determined by ¹⁴C counting are r₁ = 1.04; r₂ = 0.94 [M₁ = 4(5)-vinylimidazole, M₂ = 1-methyl-4-vinylimidazole] and r₁ = 1.01; r₂ = 0.86 [M₁ = 4(5)-vinylimidazole, M₂ = 1-methyl-5-vinylimidazole]. The esterolytic activity of the copolymers for the hydrolysis of p-nitrophenyl acetate (PNPA) at pH 7–8 in 28.5% ethanol–water was higher than that of the mixtures of homopolymers. At pH 5–6 the esterolytic activities of the copolymers and the mixtures were similar. The most efficient esterolytic activity for PNPA hydrolysis at pH 7.11 in 28.5% ethanol–water occurred for copolymers containing 75 mole % 4(5)-vinylimidazole and for copolymers containing 1-methyl-4-vinylimidazole rather than 1-methyl-5-vinylimidazole.     

Chain microstructure of homogeneous ethylene‐1‐alkene copolymers and characteristics of single site catalysts using a direct 13C NMR peak method. Part III. Application to ethylene–propylene copolymers showing no inversion

All relevant ¹³C NMR signals of two series of seven homogeneous ethylene–propylene copolymers were used to fit the second‐order Markov reactivity ratios of the catalysts and the theoretical feeds. The copolymers cover a very broad range of comonomer incorporations, from about 10 to 93%, and show only primary (1,2) insertions. For both series, solutions are found with reliabilities >>99.5%. The reactivity ratios, r₁₁₂ = 2.54, r₁₂₁ = 0.12, r₂₁₂ = 2.05, and r₂₂₁ = 0.29 for the used Zirconocone and r₁₁₂ = 1.69, r₁₂₁ = 0.32, r₂₁₂ = 1.56, and r₂₂₁ = 0.51 for the hafnocene, provide direct information about the metallocenes, the kinetics, and the chain microstructure. With these results, the direct peak method demonstrates that the use of all relevant ¹³C NMR peaks enables accurate second‐order Markov modeling, revealing subtle differences between copolymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 747–755, 2006     

Copolymers of 4‐(3′,4′‐Dimethoxycinnamoyl)phenyl Acrylate and MMA: Synthesis,Characterization, Photocrosslinking Properties,and Monomer Reactivity Ratios

Abstract

4‐(3′,4′‐Dimethoxycinnamoyl)phenyl acrylate (DMCPA) containing pendant chalcone moiety was copolymerized with methyl methacrylate (MMA) by radical polymerization in ethyl methyl ketone at 70°C under a nitrogen atmosphere using benzoyl peroxide (BPO) as a free radical initiator. The prepared polymer was characterized by UV, FT‐IR, ¹H‐NMR, and ¹³C‐NMR spectra. The composition of the copolymer was determined using ¹H‐NMR analysis. The monomer reactivity ratios of copolymerization were determined using conventional linearization methods such as Fineman–Ross (r ₁ = 0.26 and r ₂ = 0.61), Kelen–Tudos (r ₁ = 0.26 and r ₂ = 0.61), and Ext. Kelen–Tudos (r ₁ = 0.23 and r ₂ = 0.59), and a non‐linear error‐in‐variables model (EVM) method using the computer program RREVM (r ₁ = 0.2541 and r ₂ = 0.6094). The molecular weights (M _w and M _n) of the copolymers were determined by gel permeation chromatography. Thermogravimetric analysis of the polymers in air reveals that the stability of the copolymers decreases with an increase in the mole fraction of MMA in the copolymers. The solubility of the polymers was tested in various polar and non‐polar solvents. The glass transition temperature of the copolymers was determined as a function of copolymer composition. The copolymers were sensitive to UV light and became crosslinked after irradiation with 254 nm light.     

Self-crosslinkable polymers. I. Copolymerization of glycidyl methacrylate with 2-vinylpyridine and 2-vinyl-5-ethylpyridine

A soluble and self-crosslinkable linear copolymer with pendant epoxy and pyridyl groups was obtained from glycidyl methacrylate (M₁) and 2-vinylpyridine (M₂) or 2-vinyl-5-ethylpyridine (M₂) by the action of azobisisobutyronitrile. The monomer reactivity ratios were determined in tetrahydrofuran at 60°C: r₁ = 0.510, r₂ = 0.620 with 2-vinylpyridine and r₁ = 0.57, r₂ = 0.62 with 2-vinyl-5-ethylpyridine. These were consistent with the calculated values with the reported Q and e values for these monomers. The intrinsic viscosities of the copolymers with 2-vinylpyridine and with 2-vinyl-5-ethylpyridine were found to be 0.17–0.19 and 0.26–0.38, respectively, in tetrahydrofuran at 30°C; they were independent of the copolymer composition. The copolymers were amorphous, had no clear melting points, and became insoluble crosslinked polymers under heating without further addition of any curing agents.     

Monomer-isomerization polymerization. XVII. Monomer-isomerizations copolymerizations of 2-butene with 3-heptenes and 4-methyl-2-pentenes with Ziegler-Natta catalyst

2-Butene(2B) copolymerizes with 3-heptene(3H) and 4-methyl-2-pentene(4M2P) by a monomer-isomerization copolymerization mechanism in the presence of TiCl₃–(C₂H₅)₃Al catalyst at 80°C to yield the copolymers of 1-olefin units. By comparison, the copolymerization of 1-butene(1B) with 4-methyl-1-pentene(4M1P) was also carried out under similar conditions. The composition of the copolymers obtained from these copolymerizations was determined from the ratios of optical densities D₇₂₃/D₁₃₈₀ and D₁₁₇₀/D₁₃₈₀ in their infrared (IR) spectra. The apparent monomer reactivity ratios for the monomer-isomerization copolymerization of 2B with 3H and 4M2P, in which the concentration of olefin monomer in the feed was used as 2-olefin, were determined as follows: cis-2B(M₁)/3H(M₂); r₁ = 4.00, r₂ = 0.20: trans-2B(M₁)/3H; r₁ = 3.50, r₂ = 0.20; 4M2P(M₁)-trans-2B(M₂): r₁ = 0.05, r₂ = 9.0. These results indicate that the isomerization of 2-olefins to 1-olefins was important to monomer-isomerization copolymerization.     

Poly(chloroaldehydes). IV. Copolymerization of chloral and dichloroacetaldehyde catalyzed by organometallic compounds

The copolymerization of chloral and dichloroacetaldehyde (DCA) has been studied with the use of organometallic compounds as initiators. The alkylzincs were the most effective catalysts, giving good conversions to copolymers of apparently high molecular weight. The polymerizations were best carried out at temperatures below ?40°C. at an initiator concentration of at least 0.4 mmole/mole of monomers. The copolymerization proceeds to high conversions in toluene as the solvent, but the presence of small amounts of either n-heptane or tetrahydrofuran greatly decreases the yield. This, coupled with the fact that little polymerization occurs at DCA concentrations above 70 mole-%, leads to the proposal of a propagation reaction mechanism involving the coordination of the monomeric aldehydes with a cyclic zinc alkoxide dimer. Monomer reactivity ratios with chloral as M₁ and DCA as M₂ were r₁ = 1.50 and r₂ = 0.65. The copolymer is stiff and inelastic with a tensile strength of ca. 6000 psi.     

Thermal degradation of copolymers of butadiene and acrylonitrile

Ten copolymers of butadiene and acrylonitrile have been prepared covering the composition range 100-25 mole % butadiene; reactivity ratios are r_butadiene = 0?50, r_{acrylonitrile} = 0?07. The thermal analysis techniques (TVA, TGA and DSC) have been applied to determine the general features of the thermal degradation of these copolymers. The fractions of products comprising permanent gases, products volatile at 20°, chain fragment material and residue have been separated and analysed. The constituent parts of the overall reaction have been discussed and the whole represented in the form of an integrated reaction mechanism.     

Organometallic polymers. XIV. Copolymerization of vinylcyclopentadienyl manganese tricarbonyl and vinylferrocene with N-vinyl-2-pyrrolidone

N-Vinyl-2-pyrrolidone(I) has been copolymerized with vinylferrocene(II) and vinylcyclopentadienyl manganese tricarbonyl(III) in degassed benzene solutions with the use of azobisisobutyronitrile (AIBN) as the initiator. The polymerizations proceed smoothly, and the relative reactivity ratios were determined as r₁ = 0.66, r₂ = 0.40 (for copolymerization of I with II, M₁ defined as II) and r₁ = 0.14 and r₂ = 0.09 (for copolymerization of I with III, M₁ defined as III). These copolymers were soluble in benzene, THF, chloroform, CCl₄, and DMF. Molecular weights were determined by viscosity and gel-permeation chromatography studies (universal calibration technique.) The copolymers exhibited values of M?_n between 5 × 10³ and 10 × 10³ and M?_w between 7 × 10³ and 17 × 10³ with M?_w/M?_n < 2. Upon heating to 260°C under N₂, copolymers of III underwent gas evolution and weight loss. The weight loss was enhanced at 300°C, and the polymers became in creasingly insoluble. Copolymers of vinylferrocene were oxidized to polyferricinium salts upon treatment with dichlorodicyanoquinone (DDQ) or o-chloranil (o-CA) in benzene. Each unit of quinone incorporated into the polysalts had been reduced to its radical anion. The ratio of ferrocene to ferricinium units in the polysalts was determined. The polysalts did not melt at 360°C and were readily soluble only in DMF.     

Crystallization of markoffian copolymers

An equilibrium theory is proposed for crystallization of (A, B) binary copolymers whose comonomeric unit sequences are statistically described by conditional pair probabilities P_AA, P_AB, P_BA, and P_BB. These are linked to the product of the reactivity ratios by r = r_Ar_B = (P_AAP_BB)/(P_ABP_BA). Three cases are considered here, (i) B units are rejected from the crystals, (ii) cocrystallization of A and B comonomeric units is possible in the full range of compositions within a single crystal structure (copolymer isomorphism), (iii) cocrystallization takes place either in a poly(A)-type or in a poly(B)-type structure, depending on composition (copolymer isodimorphism). For case (i) crystallization the theory demonstrates, according to expectation, that alternating copolymers (r = 0) produce the largest melting point depression, whereas in case (ii) they give rise to the smallest composition difference between the crystals and the liquid. The theory developed here further illustrates that for binary copolymers which are isodimorphic (case iii), a phase diagram is obtained similar to that for a classical binary system of small molecules.     

Self-crosslinkable polymers. IV. Copolymerization of 1-ethenyl-4-(2,3-epoxy-1-propoxy)benzene with vinylpyridines

Soluble and self-crosslinkable linear copolymers with pendant epoxy and pyridyl groups were obtained from 1-ethenyl-4-(2,3-epoxy-1-propoxy)benzene (M₁) and vinylpyridines (M₂) by the action of α,α′-azobisisobutyronitrile. The monomer reactivity ratios were determined in tetrahydrofuran at 60°C (r₁, r₂, and vinylpyridine given): 0.467, 0.638, 4-vinylpyridine; 0.556, 1.25, 2-vinylpyridine; 0.639, 1.38, 5-ethyl-2-vinylpyridine. The Q and e values for 1-ethenyl-4-(2,3-epoxy-1-propoxy)-benzene were calculated as 1.3–1.6 and ?1.1–?1.3, respectively, with the reported Q–e values for these vinylpyridines. The intrinsic viscosities of the copolymers were found to be 0.15–0.30 in tetrahydrofuran at 30°C and to be dependent on the copolymer composition. The copolymers with these vinylpyridines were amorphous, had no clear melting points, and became insoluble crosslinked polymers under heating without further addition of any curing agents.     

Acrylonitrile–4-vinylpyridine copolymers effect of comonomer sequence distribution on properties

Acrylonitrile–,4-vinylpyridine copolymers were prepared in chloroform solution at 60°C with AIBN as initiator. Copolymer compositions were determined from their 15.01-MHz ¹³C-NMR spectra. Reactivity ratios of r_AN = 0.093 and r_4VP = 0.32 were calculated by the Kelen and Tudos method. The run number, number-average sequence lengths, and monomer sequence distributions were also calculated. The T_g values of the copolymers, their dye uptake, and degree of alkaline hydrolysis were influenced by the overall copolymer composition but particularly by the monomer sequence distribution in the copolymers.