Aminobutadienes. X. Polymerization and copolymerization of 2-phthalimidomethyl-1,3-butadiene

The polymerization and copolymerization of 2-phthalimidomethyl-1,3-butadiene were investigated. This monomer was easily polymerized by benzoyl peroxide catalyst in bulk or in solvent, and by γ-radiation in the solid state to give polymers having a softening point of 135–145°C. Although these resulting polymers did not give x-ray diffraction patterns, they showed crystalline patterns by electron diffraction. On the other hand, cationic polymerization with the use of boron trifluoride diethyl etherate in chloroform was attempted, but no formation of the polymer was observed. Also, this monomer was easily copolymerized with styrene in N,N-dimethylformamide. The monomer reactivity ratios and Alfrey-Price Q and e values calculated from the copolymerization data of this monomer (M₁) with styrene (M₂) were r₁ = 2.0 ± 0.13, r₂ = 0.15 ± 0.02, and Q₁ = 2.78, e₁ = 0.30.     

Polymerization and copolymerization of 2-phthalimidomethyl 1,3-butadiene. I. Preliminary studies of free radical polymerization and polymerizations initiated by various transition metal allyl complexes

2-Phthalimidomethyl 1,3-butadiene was homopolymerized and copolymerized with butadiene by free radical initiators; r₁ and r₂ were close to 1. All the attempts to polymerize 2PMB anionically have been unsuccessful. Preliminary studies of various η³-allylic catalysts showed that η³-allyl M₀(CO)₃OOCCF₃ initiates the polymerization of butadiene and is not sensitive to N-methyl phthalimide (NMP); neither does it initiate the copolymerization of butadiene and 2PMB. On the other hand, a catalyst that results from the reaction of allyl trifluoroacetate with nickel tetracarbonyl is efficient for the copolymerization of butadiene and 2PMB. η³-Allyl nickel trifluoroacetate was prepared in heptane or benzene and used in benzene or methylene chloride. In all cases it initiated the copolymerization of butadiene with 2PMB     

Preparation,copolymerization kinetics,and viscoelastic behavior of copolymers of 1,3-butadiene and 1,4-diphenyl-1,3-butadiene

1,4-Diphenyl-1,3-butadiene reacts readily with sec-butyllithium in toluene to form adducts. Although this 1,4-substituted conjugated diene did not homopolymerize or copolymerize with styrene, with butadiene it formed copolymers having compositions varying from one end of the chain to the other. The monomer reactivity ratios found were r₁ = 8.2, r₂ = 0 in toluene and r₁ = 2.1, r₂ = 0 in toluene–tetrahydrofuran (0.2%) solution. The intramolecular composition distribution of these polymers varied from an initial butadiene-rich composition, dependent on the ratio of monomers charged, to the equimolar composition of the alternating copolymer. In spite of this compositional heterogeneity, the crosslinked polymers exhibited a single glass transition characteristic of the mean composition. A secondary, high-temperature dispersion observed in the dynamic viscoelastic properties of some of the products is shown to be attributable to network topological effects.     

Aminobutadienes. VI. Polymerization and Copolymerization of 2-Phthalimido-1,3-butadiene

2-Phthalimido-1,3-butadiene (2-PB) was polymerized either radically or thermally in bulk and in solution. While the polymer obtained by solution polymerization was soluble in some solvents such as halogenated hydrocarbons, dioxane, and dimethylformamide and had a softening point in the range of 160–170°C., that obtained by polymerization in bulk was insoluble in any solvent and only swollen on being immersed in such solvents as above. The reduced viscosity of the soluble polymer obtained by solution polymerization was approximately 1.0, and this value remained almost unchanged with varying polymerization time. Likewise the cationic polymerization in acetylene tetrachloride or in chloroform at 20°C. with the use of cationic catalysts such as boron trifluoride and stannic chloride was attempted, but no formation of polymer was observed. This monomer preferentially reacted with acrylonitrile, methyl methacrylate, styrene, and N-vinylphthalimide to form the respective copolymers; it reacted somewhat less readily with vinyl acetate. The monomer reactivity ratios in the copolymerization with styrene were calculated by the Fineman and Ross method and found to be r₁ (2-PB) = 5.2 and r₂ (styrene) = 0.11, respectively, from which the Q, e parameters were successively evaluated to be Q = 5.0 and e = ?0.05. The fact that e value is close to zero, easily explains why this monomer can copolymerize well both with acrylonitrile, which has a highly positive value of e (1.2) and with styrene, for which e is considerably negative (-0.8).     

Thermal isomerization and decomposition of 1,2-butadiene in shock waves

1,2-Butadiene diluted with Ar was heated behind reflected shock waves over the temperature and the total density range of 1100–1600 K and 1.36 × 10^?5 ? 1.75 × 10^?5 mol/cm³. The major products were 1,3-butadiene, 1-butyne, 2-butyne, vinylacetylene, diacetylene, allene, propyne, C₂H₆, C₂H₄, CH₄, and benzene, which were analyzed by gas chromatography. The UV kinetic absorption spectroscopy at 230 nm showed that 1,2-butadiene rapidly isomerizes to 1,3-butadiene from the initial stage of the reaction above 1200 K. In order to interpret the formation of 1,3-butadiene, 1-butyne, and 2-butyne, it was necessary to include the parallel isomerizations of 1,2-butadiene to these isomers. The present data were successfuly modeled with a 82 reaction mechanism. From the modeling, rate constant expressions were derived for the isomerization 1,2-butadiene = 1,3-butadiene to be k₃ = 2.5 × 10¹³ exp(?63 kcal/RT) s^?1 and for the decomposition 1,2-butadiene = C₃H₃ + CH₃ to be k₆ = 2.0 × 10¹⁵ exp(?75 kcal/RT) s^?1, where the activation energies, 63 kcal/mol and 75 kcal/mol, were assumed. These rate constants are only applicable under the present experimental conditions, 1100–1600 K and 1.23–2.30 atm. © 1995 John Wiley & Sons, Inc.     

Silyl enol ethers as monomer. III. Radical polymerization and copolymerizations of 2-trimethylsilyloxy-1,3-butadiene and desilylation of the resulting polymers

2-Trimethylsilyloxy-1,3-butadiene (TMSBD), the silyl enol ether of methyl vinyl ketone, was homopolymerized with a radical initiator to afford polymers with a molecular weight of ca. 10⁴. Radical copolymerizations of TMSBD with styrene (ST) and acrylonitrile (AN) in bulk or dioxane at 60°C gave the following monomer reactivity ratios: r₁ = 0.64 and r₂ = 1.20 for the ST (M₁)–TMSBD (M₂) system and r₁ = 0.036 and r₂ = 0.065 for the AN (M₁)–TMSBD (M₂) system. The Q and e values of TMSBD determined from the reactivity ratios for the former copolymerization system were 2.34 and ?1.31, respectively. The resulting polymer and copolymers were readily desilylated with hydrochloric acid or tetrabutylammonium fluoride as catalyst to yield analogous polymers having carbonyl groups in the polymer chains.     

Block copolymerization of allene derivatives with 1,3-butadiene by living coordination polymerization with π-allylnickel catalyst

The block copolymerization of allene derivatives (3A–3D) with 1,3-butadiene (2) by [(allyl)NiOCOCF₃]₂ (1) is described. For instance, the living coordination polymerization of phenylallene (3A, 50 equiv) starting from the living poly(2), which was prepared by the polymerization of 2 (160 equiv) by 1, successfully gave a block copolymer of 2 and 3A in high yield. The molecular weight of the block copolymer (4A) in gel permeation chromatography shifted clearly to the higher molecular weight region and kept a unimodal distribution (M_n = 17,400, M_w/M_n = 1.23) in comparison with that of the starting living poly(2) (M_n = 5,600, M_w/M_n = 1.67). The ratio of each segment and the molecular weight of the resulting copolymers could be controlled by the feed ratio of each monomer. The block copolymerization also proceeded successfully by the inverse order of the monomer feeding (i.e., the polymerization of 3A followed by that of 2) to obtain the corresponding block copolymers in high yields. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3916–3921, 1999     

Cationic copolymerization of 2-methylene-5,5-dimethyl-1,3-dioxane with 2-methylene-1,3-dioxolane and 2-methylene-1,3-dioxane

Copolymers of the cyclic ketene acetals, 2-methylene-5,5-dimethyl-1,3-dioxane, 3 , (M₁) with 2-methylene-1,3-dioxolane, 4 , (M₂) or 2-methylene-1,3-dioxane, 5 , (M₂), were synthesized by cationic copolymerization. An experimental method was designed to study the reactivity of these very reactive and extremely acid sensitive cyclic ketene acetal monomers. The reactivity ratios, calculated using a computer program based on a nonlinear minimization algorithm, were r₁ = 6.36 and r₂ = 1.25 for the copolymerization of 3 with 4 , and r₁ = 1.56 and r₂ = 1.42 for the copolymerization of 3 with 5. FTIR and ¹H-NMR spectra when combined with the values of r₁ and r₂ showed that these copolymers were formed by a cationic 1,2-polymerization (ring-retained) route. Furthermore the tendency existed to form very short blocks of M₁ or M₂ within the copolymers. Cationic copolymerization of cyclic ketene acetals have the potential to be used for synthesis of novel polymers. © 1996 John Wiley & Sons, Inc.     

Monomer-isomerization oligomerization of 2-ethyl-1,3-butadiene by acid catalysts

The cationic oligomerization of 2-ethyl-1,3-butadiene (2EBD) by a superacid (CF₃SO₃H) and a superacid derivative (CH₃COClO₄) accompanied monomer isomerization to 3-methyl-1,3-pentadiene (3MPD) before propagation to yield oligomers of the isomerized monomer as main products in benzene at 50°C. Detection of 3MPD in the reaction mixture and ¹H-NMR structural analysis of the produced oligomers confirmed the occurrence of this “monomer-isomerization oligomerization.” On the other hand, in the presence of a metal halide catalyst (BF₃OEt₂) 2EBD reacted without isomerization and yielded oligomers that were different from those produced by the foregoing superacid catalysts. Monomer isomerization was suppressed in a polar solvent [(CH₂Cl)₂] or at lower temperatures. The mechanism of the oligomerization with monomer isomerization was discussed.     

CO2 laser-induced photolysis of spirohexane: Time resolved observation of vibrationally excited 1,3-butadiene

Vibrationally excited spirohexane (SHX) generated in CO₂ laser irradiation undergoes photolysis producing ethylene, 1,3-butadiene and a C₄ compound as major products. Collisional energy pooling plays a major role in the multiphoton excitation process. Time-resolved formation of 1,3-butadiene is monitored by UV absorption from which the unimolecular rate constant for SHX dissociation is found to be 5.6 × 10⁵ s⁻¹. A red shift of 4O nm observed in the transient UV absorption spectrum has been assigned to nascent 1,3-butadiene, which suggests that vibrationally hot 1,3-butadiene molecules are formed. The effects of laser energy fluence and pressure of SF₆ as a sensitizer on dissociation yield are also investigated.     

Photooxidation of 1,3-butadiene containing systems: Rate constant determination for the reaction of acrolein with ⋅OH radicals

The photooxidation of the 1,3-butadiene–NO–air system at 298 ± 2 K was investigated in an environmental chamber under simulated atmospheric conditions. The irradiation gave rise to the formation of acrolein in a 55% yield, based on 1,3-butadiene initial concentration for all the experimental runs. The rate of formation of acrolein was the same as that of 1,3-butadiene consumption, indicating that acrolein is the major product of the 1,3-butadiene oxidation in air. The dependence of acrolein concentration on irradiation time showed thata secondary process, identified as an oxidation of acrolein by ^?OH radicals, was occurring during the photochemical runs. The rate constant of this secondary process was determined by measuring the relative rates of disappearance of acrolein and n-butane during the irradiation of acrolein-n-butane-NO-air mixtures. The so obtained relative rate constant value was placed on an absolute basis using a reported rate constant for the n-butane + ^?OH reaction; a value of (1.6 ± 0.2) × 10¹⁰ M^?1 sec^?1 was obtained.     

Effect of reaction medium on copolymerization of acrylonitrile and methyl acrylate

The copolymerization of acrylonitrile (AN) with methyl acrylate (MEA) has been investigated in three types of polymerization, i.e., emulsion polymerization in water with a water-soluble initiator, suspension polymerization in water with an oil-soluble and water-insoluble initiator, and solution polymerization in dimethyl sulfoxide (DMSO). Monomer reactivity ratios at 50°C. for AN and MEA are found to be r₁ = 0.78 ± 0.02, r₂ = 1.04 ± 0.02 in emulsion polymerization; r₁ = 1.02 ± 0.02, r₂ = 0.70 ± 0.02 in DMSO solution polymerization; r₁ = 0.75 ± 0.05, r₂ = 1.54 ± 0.05 in suspension polymerization. The large differences found in the reactivity ratios may be attributed to the different ratio of concentration of two monomers in the loci of polymerization. Chemically, AN is somewhat more reactive than MEA as shown by the reactivity ratios in DMSO. In the case of the suspension polymerization, the MEA/AN ratio in the polymer particles in which polymerization occurs may be higher than that in the total phase. Experimental results of the emulsion polymerization show that the emulsion polymerization of AN occurs both in the particles and in water. In addition, rates of the copolymerization of AN with MEA have also been investigated.     

Triallylstannyllithium-allyllithium as an initiator for the anionic reversible chain transfer polymerization of 1,3-butadiene

The anionic polymerization of 1,3-butadiene using a novel metalloidal anion initiator, triallylstannyllithium (TALi)-allyllithium (ALi), was studied. The TALi-ALi initiated anionic polymerization of 1,3-butadiene gave the star polymer along with the linear polybutadiene (PBD). The star polymer consisted of three PBD branches and a central tin atom. What is striking is a fact that the number-average molecular weights (M_n) and molecular weight distribution of three PBD branches and linear PBD were almost identical. A reversible chain transfer polymerization mechanism, which includes the equilibrium between tri(macroallyl)-stannyllithium and macroallylic anion, is proposed. © 1996 John Wiley & Sons, Inc.     

2-alkyl-1,3-butadiene polymerization under the influence of π-allylic complexes of transition metals

Stereoregulation in the polymerization of 2-alkyl-1,3-butadienes with transition metal π-allylic complexes has been studied. The direction of isoprene polymerization is shown to be a function of the nature of the metal and ligands in the allylic compound. The presence of acidic ligands in π-allylic complexes of Zr, Cr, Mo, and Co contributes to 1,4-addition and increases the selectivity of π-allylic nickel complexes, favoring cis-1,4-structure formation. Investigation of the model reaction of 2-alkyl-1,3-butadienes with bis(π-perdeuterocrotyl nickel iodide) revealed that active sites have an π-allylic type structure. The mechanism of formation of π-allylic adducts and the main factors which determine the dependence of direction and rate of polymerization on the nature of a monomer in the diene series: 2-methyl-1,3-butadiene(isoprene), 2-ethyl-1,3-butadiene, 2-isopropyl-1,3-butadiene, and 2-tert-butyl-1,3-butadiene, are discussed.     

Synthesis of degradable poly(methyl methacrylate) star polymers via RAFT copolymerization with cyclic ketene acetals

Copolymerization of the cyclic ketene acetal 5,6‐benzo‐2‐methylene‐1,3‐dioxepane (BMDO) with methyl methacrylate (MMA) is studied with respect to its copolymerization parameters and the suitability to control BMDO/MMA copolymerizations via the reversible addition‐fragmentation chain transfer (RAFT) technique to obtain linear and 4‐arm star polymers. BMDO shows disparate copolymerization behavior with MMA and r₁ = 0.33 ± 0.06 and r₂ = 6.0 ± 0.8 have been determined for polymerization at 110 °C in anisole from fitting copolymer composition vs. comonomer feed data to the Lewis–Mayo equation. Copolymerization of the two monomers is successful in RAFT polymerization employing a trithiocarbonate control agent. As desired, polymers contain only little amount of polyester units stemming from BMDO units and preliminary degradation experiment show that the polymer degrades slowly, but steadily in aqueous 1 M NaOH dispersion. Within ten days, the polymers are broken down to low molecular weight segments from an initial molecular weight of M_n = 6000 g mol^?1. Star (co)polymerization with an erythritol‐based tetra‐functional RAFT agent following the Z‐group approach proceeds efficiently and polymers with a number‐average molecular weight of 10,000 g mol^?1 are readily obtained that degrade in similar manner as the linear copolymer counterparts. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1633–1641     

On the copolymerization model and microstructure of methyl acrylate - styrene radical copolymer. Influence of ZnCl2

Bulk radical copolymerization of methyl acrylate (MeA, M₁) with styrene (St, M₂) in presence and absence of ZnCl₂ as complexing agent was studied. ¹H-NMR spectra were used to establish copolymer composition and sequence distribution. The methoxy group signal was observed to be split due to pentads, but the analysis of sequence distribution is possible only at triad level. Both composition and sequence distribution data confirmed that bulk radical copolymerization respects quite well the terminal addition model; the values of r₁ = 0.14 ± 0.02 (from composition data) and r₁ = 0.25 ± 0.03 (from sequence distribution data) and r₂ = 0.83 ± 0.10 (from composition data) were found. The presence of ZnCl₂ increases the probability of alternating addition, e.g., for [ZnCl₂]/[MeA] = 0.2, r₁ = 0.03 ± 0.02 and r₂ = 0.17 ± 0.03. The radical copolymer obtained in bulk in the absence of ZnCl₂ presents a coisotactic configuration with σ = 0.75 ± 0.03, but the presence of the complexing agent reduces the probability of coisotactic addition, e.g., for [ZnCl₂]/[MeA] = 0.2, σ = 0.52 ± 0.03.     

Rate coefficients for the gas-phase reactions of bromine radicals with a series of alkenes,dienes, and aromatic hydrocarbons at 298 ± 2 K

Using the relative kinetic method rate coefficients have been determined for the gas-phase reaction of bromine (Br) radicals with a series of alkenes, chloroalkenes, dienes, and aromatic hydrocarbons in 1000 mbar of synthetic air at 298 ± 2 K. Both the UV photolysis of CH₂Br₂ (λ = 254 nm) and the visible photolysis of Br₂ (320 ≤ λ ≤ 480) were used to generate Br radicals. For the alkenes and dienes the following rate coefficients were obtained (in units of 10⁻¹² cm³ molecule⁻¹ s⁻¹): trans-2-butene 9.26 ± 1.85; 2-methyl-1-butene 15.20 ± 3.00; 2-methyl-2-butene 19.10 ± 3.80; 2,3-dimethyl-2-butene 28.20 ± 5.60; α-pinene 22.20 ± 4.40. β-pinene 28.60 ± 5.70; 1,3-butadiene 57.50 ± 11.50; isoprene 74.20 ± 14.80; and 2,3-dimethyl-1,3-butadiene 81.7 ± 16.30. For the chloroalkenes and aromatic hydrocarbons the following rate coefficients were obtained (in units of 10⁻¹³ cm³ molecule⁻¹ s⁻¹): chloroethene 7.37 ± 1.92; 1,1-dichloroethene 3.66 ± 0.73; trichloroethene 0.90 ± 0.18; tetrachloroethene ≤ 0.1; benzene ≤ 0.10; toluene ≤ 0.10; p-xylene ≤ 0.10; and furan ≤ 0.10. With the exception of trans-2-butene, this study represents the first determination of the rate coefficients for all of the compounds. © 1996 John Wiley & Sons, Inc.     

Radical-initiated homo- and copolymerization of methoxymethyl methacrylate

The kinetics of methoxymethyl methacrylate (MOMA) homopolymerization has been investigated in benzene, using azobis(isobutyronitrile) as an initiator. The rate of polymerization (R_p) could be expressed by R_p = k[AIBN]^0.5 [MOMA]^1.19. The overall activation energy was calculated to be 73.2 kJ/mol. Kinetic constants for MOMA polymerization were obtained as follows: k_p/k_t^1/2 = 0.091 L^1/2 · mol^?1/2 · s^?1/2; 2fk_d = 1.37 × 10^?5 s^?1. The values of K and a in the Mark–Houwink equation, [η] = KM^a, where K = 5.89 × 10^?5 and a = 0.82 when M = M _n and the solvent was benzene. The relative reactivity ratios of MOMA (M₂) copolymerizations with styrene (r₁ = 0.40, r₂ = 0.58) were obtained. Applying the Q-e scheme led to Q = 0.78 and e = 0.67. The glass transition temperature (T_g) of poly(MOMA) was observed to be 64°C by DSC. Thermogravimetry of poly(MOMA) showed a 10% weight loss at 230°C in air.     

Reactions of ozone with olefins: Ethylene,allene, 1,3-butadiene,and trans- 1,3-pentadiene

The reactions of O₃ with ethylene, allene, 1,3-butadiene, and trans-1,3-pentadiene have been studied in the presence of excess O₂ over the temperature range 232 to 298 K. The initial O₃ pressure was varied from 4–18 mtorr, and the olefin pressure was varied from 0.1 to 4.5 torr (ethylene), 2.8 to 39.6 torr (allene), 52.7 to 600 mtorr (1,3-butadiene) or 26.2 to 106 mtorr (trans-1,3-pentadiene). The O₃ decay was monitored by ultraviolet absorption. The reactions are first order in both O₃ and olefin, and the rate coefficients are independent of the O₂ pressure. For the O₃-ethylene system, various diluent gases (O₂, N₂, air) were used and the rate coefficients were found to be independent of the nature of the diluent gas. The various rate coefficients fit the Arrhenius expressions (k in cm³ s^?1): where the reported uncertainties are one standard deviation and R is in cal/mol K.     

Radical polymerization of ortho-(1,3-dioxolan-2-yl)phenyl ethyl fumarate involving intramolecular hydrogen abstraction and ring opening of cyclic acetal

The polymerization of o-(1,3-dioxolan-2-yl)phenyl ethyl fumarate (DOPEF) initiated with dimethyl 2,2′-azobisiso-butyrate (MAIB) was studied kinetically in benzene. The polymerization rate (R_p) at 60°C was given by R_p = k [MAIB]^0.76 [DOPEF]^0.71. The overall activation energy of polymerization was calculated to be 98.3 kJ/mol. The number-average molecular weight of resulting poly(DOPEF) was in the range of 1000–3100. ¹H- and ¹³C-NMR spectra of resulting polymers revealed that the radical polymerization of DOPEF proceeds in a complicated manner involving vinyl addition, intramolecular hydrogen abstraction, and further ring opening of the cyclic acetal at higher temperatures. From the copolymerization of DOPEF (M₁) and styrene (St) (M₂) at 60°C, the monomer reactivity ratios were obtained to be r₁ = 0.02 and r₂ = 0.20, the values of which are similar to those of the copolymerization of ethyl o-formylphenyl fumarate and St. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 563–572, 1998