Polymerization of aromatic aldehydes. IV. Cationic copolymerization of phthalaldehyde isomers and styrene

Copolymerizations of three phthalaldehyde isomers (M₂) with styrene (M₁) were carried out in methylene chloride or in toluene with BF₃OEt₂ catalyst. The monomer reactivity ratios were r₁ = 0.77, r₂ = 0 for the meta isomer and r₁ = 0.60, r₂ = 0 for the para isomer. The second aldehyde group of both isomers did not participate in polymerization and acted simply as the electron-withdrawing group, thus reducing the cationic reactivity of these monomers. Copolymerization behaviors of the ortho isomer (o-PhA) were quite different between 0°C and ?78°C. At ?78°C, o-PhA preferentially polymerized to yield “living” cyclopolymers, until an equilibrium concentration of o-PhA monomer was reached. Then, styrene propagated from the living terminal rather slowly. The block structure of the copolymer was confirmed by the chemical and spectroscopic means. In the copolymerization at 0°C, the o-PhA unit in copolymer consisted both of cyclized and uncyclized units. This copolymer seemed to contain short o-PhA sequences. The variation of the o-PhA-St copolymer structure with the polymerization temperature was explained on the basis of whether the polymerization was carried out above or below the ceiling temperature (?43°C) of the homopolymerization of o-PhA.     

Application of the monomer reactivity ratios to the kinetic‐model discrimination and the solvent‐effect determination for the styrene/acrylonitrile monomer system

The impact of reactivity ratios determined with the Nelder and Mead simplex method on the kinetic‐model discrimination and the solvent‐effect determination for the styrene/acrylonitrile monomer system was investigated. For the monomer system, the penultimate unit effect was inversely proportional to the polarity of the solvent: acetonitrile < N,N‐dimethylformamide < methyl ethyl ketone < toluene. Quantitatively, the penultimate unit effect could be correlated with an absolute value of the difference between the standard deviation of the reactivity ratios determined for the terminal and penultimate models. By application of the F test, the penultimate model was justified for copolymerization in toluene. The conclusion was less certain for polymerization in methyl ethyl ketone. With a scanning procedure based on the simplex method, it was found that an equivalent representation of the copolymer‐composition data could be achieved with multiple sets of penultimate‐model reactivity ratios. However, the relationship between the triad‐sequence distribution and copolymer composition depended on the reactivity‐ratio set chosen for the microstructure determination. The microstructure calculated with the penultimate‐model reactivity ratios determined with the simplex method from the initial guess (r₁₁ = r₁, r₂₁ = 1/r₂, r₂₂ = r₂, r₁₂ = 1/r₁) did not obey the general “bootstrap effect” rule. This observation still requires some theoretical interpretation. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 846–854, 2000     

Alternating copolymerization of bis(hexafluoroisopropyl) fumarate with styrene and vinyl pentafluorobenzoate: Transparent and low refractive index polymers

Bis(hexafluoroisopropyl) fumarate (BHFIPF) did not homopolymerize with free radical initiators. However, BHFIPF yielded alternating copolymers with styrene in bulk with Azobisisobutyronitrile (AIBN) as a radical initiator. The monomer reactivity ratios of BHFIPF (M₁) and styrene (M₂) were calculated as r₁ = 0.00 and r₂ = 0.02. BHFIPF also copolymerized with vinyl pentafluorobenzoate (VPFB) in bulk and in pentafluoroisopropanol solution to produce an alternating copolymer. The reactivity ratios of BHFIPF (M₁) with VPFB (M₂) were r₁ = 0.00 and r₂ = 0.05 in bulk and r₁ = 0.01 and r₂ = 0.11 in pentafluoroisopropanol, respectively. The glass transition temperatures (T_g) of the BHFIPF‐styrene and BHFIPF‐VPFB copolymers were 107 and 86 °C, respectively. The BHFIPF‐styrene copolymer was thermally stable, and the thermal degradation temperature (T_d) was 400 °C, whereas the T_d of BHFIPF‐VPFB copolymer was 240 °C. The films obtained by casting from tetrahydrofuran (THF) solutions of these copolymers were flexible and transparent. Their refractive indices were 1.4048 for the BHFIPF‐styrene copolymer, and 1.3980 for the BHFIPF‐VPFB copolymer at 633 nm, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Radical polymerization of butadiene-1-carboxylic acid

The homopolymerization and copolymerization of butadiene-1-carboxylic acid (Bu-1-Acid) (M₁) were studied in tetrahydrofuran at 50°C with azobisisobutyronitrile as an initiator. The initial rate of polymerization was proportional to [AIBN]^1/2 and [Bu-1-Acid]¹. The overall activation energy for the polymerization was 22.87 kcal/mole. For copolymerization with styrene (M₂) and acrylonitrile (M₂), the monomer reactivity ratios r₁, r₂ were determined by the Fineman-Ross method, as follows; r₁ = 5.55, r₂ = 0.08 (M₂ = styrene); r₁ = 11.0, r₂ = 0.03 (M₂ = acrylonitrile). Alfrey-Price Q-e values calculated from these values were 6.0 and +0.11, respectively. The Bu-1-Acid unit in the copolymer as well as the homopolymer was found from infrared and NMR spectral analyses to be composed of a trans-1,4 bond. The hydrogen-transfer polymerization of Bu-1-Acid leading to polyester was attempted with triphenylphosphine as initiator, but did not occur.     

Poly(isobornyl methacrylate‐co‐methyl acrylate): Synthesis and stereosequence distribution analysis by NMR spectroscopy

Copolymerization of isobornyl methacrylate and methyl acrylate ( I/M ) is performed by atom transfer radical polymerization using methyl‐2‐bromopropionate as an initiator and PMDETA/CuBr as catalyst under nitrogen atmosphere at 70 °C. The copolymer compositions determined from ¹H NMR spectra are used to determine reactivity ratios of the monomers. The reactivity ratio determined from linear Kelen–Tudos method and non‐linear error‐in‐variable method, are r_I = 1.25 ± 0.10, r_M = 0.84 ± 0.08 and r_I = 1.20, r_M = 0.82, respectively. 1D, distortion less enhancement by polarization transfer and 2D, heteronuclear single quantum coherence, and total correlation spectroscopy NMR experiments are employed to resolve highly overlapped and complex ¹H and ¹³C{¹H} NMR spectra of the copolymers. The carbonyl carbon of I and M units and methyl carbon of I unit are assigned up to triad compositional and configurational sequences, whereas β‐methylene carbons are assigned up to tetrad compositional and configurational sequences. Similarly, methine carbon of I unit is assigned up to triad level. The couplings of carbonyl carbon and quaternary carbon resonances are studied in detail using 2D hetero nuclear multiple bond correlation spectra. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Alternating Copolymers of Limonene with Methyl Methacrylate: Kinetics and Mechanism

The radical copolymerization of limonene (optically active) with methyl methacrylate in xylene at 80±0.1°C for 1 hr, initiated by benzoyl peroxide (BPO) yield alternating copolymer(s), under the inert atmosphere of nitrogen, as evidenced by reactivity ratios r₁ (MMA)=0.07 and r₂ (limonene)=0.012 using the Kelen–Tüdos method. The kinetic expression is Rα[I]^0.5[MMA]^1.0[Lim.]^?1.0. The decrease in the rate of polymerization with increase in concentration of limonene is due to penultimate unit effect. The overall energy of activation is calculated as 49 kJ/mole. FTIR of the copolymer(s) shows the characteristic frequencies at 1732.40 and 2951.40 cm^?1 due to –OCH₃ of MMA and aromatic C–H stretching of limonene, respectively. ¹H NMR spectra shows peak at 3.8–4.1 δ and 5.3–5.6 δ due to –OCH₃ of MMA and trisubstituted olefinic protons [–CH=CH–CH₂–] of limonene, respectively.     

Copolymerization of allyl esters of some fatty acids

Attempts have been made unsuccessfully to homopolymerize a number of allyl esters of substituted fatty acids by radical initiation in emulsion systems. Copolymerizations of these allyl esters with styrene, methyl methacrylate, and vinyl chloride have been investigated. Of these comonomers, styrene and methyl methacrylate do not copolymerize well with the allyl esters, whereas vinyl chloride does. Reactivity ratios for the radical copolymerization of allyl 11-iodoundecanoate, M₁, and vinyl chloride, M₂, determined at 60°C. in benzene, are r₁ = 0.42 and r₂ = 1.64. A copolymer of allyl 10, 11-dibromoundecanoate and vinyl chloride was fractionated and found to be fairly homogeneous.     

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.     

Copolymerization of 2-Hydroxypropyl Methacrylate with Alkyl Met hacrylates

2-Hydroxypropyl methacrylate (2-HPMA) has been copolym-erized with ethyl methacrylate (EMA), n-butyl methacrylate (BMA), and 2-ethylhexyl methacrylate (EHMA) in bulk at 60°C using benzoyl peroxide as initiator. The copolymer composition has been determined from the hydroxyl content. The reactivity ratios have been calculated by the Yezrielev, Brokhina, and Raskin method. For copolymerization of 2-HPMA (M₁) with EMA (M₂), the reactivity ratios are r₁ = 1.807 ± 0.032 and r₂ = 0.245 ± 0.021; with BMA (M₂) they are n = 2.378 ± 0.001 and r₂ = 0.19 ± 0.01; and with EHMA the values are r₁ = 4.370 ± 0.048 and r₂ = 0.103 ± 0.006. Since reactivity ratios are the measure of distribution of monomer units in copolymer chain, the values obtained are compared and discussed. This enables us to choose a suitable copolymer for synthesizing thermoset acrylic polymers, which are obtained from cross-linking of hydroxy functional groups of HPMA units, for specific end-uses.     

Free-Radical Copolymerization of Methyl Methacrylate and a-Methacrylophenone. II. Sequence Distribution through13 C-[1H] NMR Spectroscopy

Sequence distribution in methyl methacrylate (A)-methacrylo-phenone (B) copolymers obtained by free-radical copolymerization at 60°C has been studied by ^l3C-[¹H] NMR spectroscopy. Quantitative analysis of the resonance patterns of the quaternary carbon atom of A units and of the α -CH₃ carbon atoms of A and B units has been carried out, considering both compositional and configurational effects. All the kinetic and structural data may be readily taken into account by a scheme in which copolymerization obeys a penultimate unit model characterized by the four reactivity ratios r., = 1.77 ± 0.02, r = 2.30 ± 0.10, r_BB = 0.058 ± 0.01, r_AB = 0.325 ± 0.03. The stereochemistry of the cross-propagation steps may be described by a single cotacticity parameter: a = σ_AB = σ_BA ? 0.40. Its relatively high value probably arises from the great steric hindrance and the high polarizability of the aromatic keto group of methacrylo-phenone.     

Synthesis and Chiroptical Properties of Poly[N-(4-N′-(α-Methylbenzyl)-Aminocarbonylphenyl)-Mamaleimide]

Abstract

Radical homopolymerization of N-[4-N′-(α-methylbenzyl)-aminocarbonylphenyl]maleimide ((S)-MBCP) was carried out at 50 and 70°C for 24 h to give optically active polymers ([α]²⁵ _D = 159.8 to 163.4°). Radical copolymerizations of (S)-MBCP (M₁) were performed with styrene (ST, M₂, methyl methacrylate (MMA, M²) in THF at 50°C. The monomer reactivity ratios (r ₁, r ₂) and the Alfrey-Price Q, e values were determined as follows: r ₁ = 0.32, r ₂= 0.14, Q ₁ = 1.74, e ₁ = 0.96 in the (S)-MBCP-ST system; r ₁ = 0.54, r ₂ = 0.93, Q ₁ = 1.11, e ₁ = 1.23 in the (S)-MBCP-MMA system. Chiroptical properties of the polymers and the copolymers were also investigated, and asymmetric induction into the copolymer main chain is discussed.     

Anionic copolymerization of optically active α-methylbenzyl methacrylate and trityl methacrylate. I. Reactivity of monomers

The monomer reactivity ratios were determined in the anionic copolymerization of (S)- or (RS)-α-methylbenzyl methacrylate (MBMA) and trityl methacrylate (TrMA) with butyllithium at ?78°C, and the stereoregularity of the yielded copolymer was investigated. In the copolymerization of (S)-MBMA (M₁) and TrMA (M₂) in toluene the monomer reactivity ratios were r₁ = 8.55 and r₂ = 0.005. On the other hand, those in the copolymerization of (RS)-MBMA with TrMA were r₁ = 4.30 and r₂ = 0.03. The copolymer of (S)-MBMA and TrMA prepared in toluene was a mixture of two types of copolymer: one consisted mainly of the (S)-MBMA unit and was highly isotactic and the other contained both monomers copiously. The same monomer reactivity ratios, r₁ = 0.39 and r₂ = 0.33, were obtained in the copolymerizations of the (S)-MBMA–TrMA and (RS)-MBMA–TrMA systems in tetrahydrofuran (THF). The microstructures of poly[(S)-MBMA-co-TrMA] and poly-[(RS)-MBMA-co-TrMA] produced in THF were similar where the isotacticity increased with an increase in the content of the TrMA unit.     

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.     

Solution copolymerization of styrene and 2-hydroxyethyl mechacrylate.

The rate of solution copolymerization of styrene (M₁) and 2-hydroxyethyl methacrylate (M₂) was investigated by dilatometry. N,N-dimethyl formamide, toluene, isopropyl alcohol, and butyl alcohol were used as solvents. Polymerization was initiated by α,α′-azobisisobutyronitrile at 60°C. The initial copolymerization rate increased nonlinearly with increasing 2-hydroxyethyl methacrylate (HEMA)/styrene ratio. The copolymerization rate was promoted by solvents containing hydroxyl groups. Two different approaches were used for the prediction of copolymerization rates. The relationships proposed for the copolymerization rates calculation involve the effects of the total monomer concentration, mole fraction of HEMA, and of the solvent type. Different reactivity ratios were found in polar and nonpolar solvents: r₁ = 0.53, r₂ = 0.59 in N,N-dimethyl formamide, isopropyl alcohol and n-butyl alcohol; r₁ = 0.50, r₂ = 1.65 in toluene. The usability of these reactivity ratios was confirmed by batch experiments.     

Kinetics of free-radical copolymerization of α-methylstyrene and styrene

The free-radical copolymerization of α-methylstyrene and styrene has been studied in toluene and dimethyl phthalate solutions at 60°C. Gas chromatography was used to monitor the rate of consumption of monomers. For styrene alone, the measured rate of polymerization R_p and M?_n of the polymer coincided with values expected from previous studies by other workers. Solution viscosity η affected R_p and M?_n of styrene homopolymers and copolymers as expected on the basis of an inverse proportionality between η^1/2 and termination rate. The rate of initiation by azobisisobutyronitrile appears to be independent of monomer feed composition in this system. Molecular weights of copolymers can be accounted for by considering combinative termination only. The effects of radical chain transfer are not significant. A theory is proposed in which the rate of termination of copolymer radicals is derived statistically from an ideal free-radical polymerization model. This simple theory accounts quantitatively for R_p and M?_n data reported here and for the results of other workers who have favored more complicated reaction models because of the apparent failure of simple copolymer reactivity ratios to predict polymer composition. This deficiency results from systematic losses of low molecular weight copolymer species in some analyses. Copolymer reactivity ratios derived with the assumption of a simple copolymer model and based on rates of monomer loss can be used to predict R_p values measured in other laboratories without necessity for consideration of depropagation or penultimate unit effects. The 60°C rate constants for propagation and termination in styrene homopolymerization were taken to be 176 and 2.7 × 10⁷ mole/l.-sec, respectively. The corresponding figures for α-methylstyrene are 26 and 8.1 × 10⁸ mole/l.-sec. These constants account for the sluggish copolymerization behavior of the latter monomer and the low molecular weights of its copolymers. The simple reaction scheme proposed here suggests that high molecular weight styrene–α-methylstyrene copolymers can be produced at reasonable rates at 60°C by emulsion polymerization. This is shown to be the case.     

A study of the relative reactivity of maleic anhydride and some maleimides in free radical copolymerization and terpolymerization

Composition data for the free radical copolymerization of maleic anhydride with N-phenylmaleimide in toluene at 60°C have been obtained. Relative reactivity ratios in terminal and penultimate models using nonlinear least-squares optimization routine have been determined. The standard error was found to be somewhat smaller in the penultimate model, but is still larger than the uncertainty estimated for the copolymer composition. Terpolymers of maleic anhydride and styrene with maleimide, N-butylmaleimide, N-phenylmaleimide, and N-carbamylmaleimide were obtained. On the basis of analysis of the product composition at various monomer feeds the relative reactivity of maleic anhydride and maleimides in these reactions is compared and the influence of the structure of thesemonomers on the rate of some chain growth reactions is discussed.     

n-Octyloxyallene homopolymerization and random copolymerization with styrene using catalyst system composed of lanthanide Schiff-base complexes and Al(i-Bu)3

The catalyst system composed of lanthanide Schiff-base complexes with [3,5-tBu2 -2-(O)C6H2 CH=NC6H5]3 Ln(THF)(Ln(Salen)3 , Ln = Sc, Y, La, Nd, Sm, Gd, Yb) and triisobutyl aluminum shows high activity for n-octyloxyallene (A) homopolymerization with narrow molecular weight distribution (MWD). The influences of reaction conditions on polymerization behavior are investigated, and poly(n-octyloxyallene) has a weight average molecular weight (M w ) of 20.6 × 10 3 with MWD of 1.39 and 100% yield is obtained under the optimum conditions: [Al]/[Y] = 50 mol/mol, [A]/[Y] = 100 mol/mol, with polymerization at 80 ℃ for 16 h in bulk. The kinetic studies of n-octyloxyallene homopolymerization indicate that the polymerization rate is first-order with respect to the monomer concentration and shows some controlled polymerization characteristics. Random copolymer of n-octyloxyallene with styrene is obtained by using the same binary catalyst system; the reactivity ratios of the comonomer determined by Kelen Tüd s method are r A = 1.20 and r St = 0.35, respectively, the ratio of each segment and M w of the resulting copolymer could be controlled by varying the feed ratio of each monomer. Determined by differential scanning calorimetry, the copolymers obtained show only one glass transition temperature, which increases gradually with the increase of styrene content in the copolymer.     

Copolymers of conjugated dienes with maleic acid monoesters. IV. Reactivity ratios in copolymerization of isoprene with maleic acid monoesters

Research was carried out on copolymerization of isoprene with maleic acid monoesters in the presence of free radicals (AIBN). The aim of the study was to observe the effect of the different monoesters obtained with normal alcohols of the aliphatic series: monoethyl maleate, monopropyl maleate, monobutyl maleate, monoheptyl maleate, monolauryl maleate, and monocetyl maleate. On the basis of reactivity ratios determined by the Fineman-Ross method and compared with the Mayo-Lewis method, all the systems studied are typical cases of heterocopolymerization. The parameter r₁ is constant for this homologous series with the exception of the low terms. The experimental results agree with the ultimate model equation (with deviation at very high values of [M₁⁰]/[M₂⁰]), but not with the copolymer composition equation which considers the effect of the penultimate unity (penultimate model). Characterization of the sequential distribution is also presented (considering the effect of the terminal group only), and deviations of the experimental results are also discussed.     

Copolymerization of 4-methyl-1,3-dioxene-4 with maleic anhydride and terpolymerization with styrene as the third component

Copolymerization of 4-methyl-1,3-dioxene-4 with maleic anhydride was carried out. The monomer reactivity ratio was determined to be r₁ = 0.18, r₂ ～ 0 in terminal model and r₁ = 0.015, r₁′ = 0.224, r₂′ = r₂′ = 0 in the penultimate model. Calculations of run number, linkage probabilities, and number-average chain length in the terminal model and comparison of n (mole ratio of each monomer unit content in copolymer) in each model with the experimental value was made. From these results, the obtained polymer was confirmed to be alternating. Terpolymerization of 4-methyl-1,3-dioxene-4 with maleic anhydride and styrene was also carried out. The agreement of the experimental value (titration by indicator or electroconductivity) of maleic anhydride content with the theoretical value confirms that the terpolymer has a DMS triad sequence.