Branching generation during the free radical copolymerization of p-vinyl benzene sulfonyl chloride with styrene

The branching generation during the free radical copolymerization of chain transfer monomer p-vinyl benzene sulfonyl chloride (VBSC) with styrene was investigated by a simple mathematic model. Chain transfer constant of VBSC was determined to be around 0.3 by fitting the ¹H-NMR monitored experimental results with a mathematic model. According to the theoretical analysis, the obtained poly(VBSC) and its copolymers were substantiated to have a grafting-like main chain with residual pendent sulfonyl chloride groups after consuming most of the vinyl groups. The copolymerization results of VBSC with styrene at varied feed ratios demonstrated that conversion of sulfonyl chloride groups was lower than that of the monomer, which was in agreement with the theoretical results. The glass transition temperature, number average molecular weight and distribution of those obtained polymers were primarily investigated. Comparing with other chain transfer monomers, VBSC has a chain transfer constant much closer to unity therefore a more branched polymer is expected. Additionally, the branched polystyrene with residual sulfonyl chloride groups is hopefully to be further used as ATRP macroinitiators or reactive intermediates to synthesize functional polymers with complex structure.     

Design of maleimide monomer for higher level of alternating sequence in radical copolymerization with styrene

This work deals with design of maleimide monomer toward more precise control of alternating sequence for radical copolymerization with styrene. Crucial in this study is sequence analysis by MALDI‐TOF‐MS for resultant copolymers that was obtained via ruthenium‐catalyzed living radical copolymerization with a malonate‐based alkyl halide initiator showing selective initiation ability. The copolymers of a simple N‐alkyl maleimide [e.g., N‐ethyl maleimide (EMI)] with styrene gave complicated peak patterns for the MALDI‐TOF‐MS spectra indicating low degree of alternating sequence, in contrary to expectation from the reactivity ratios (almost zero). A simple substitution of methyl group (CH₃) of EMI with trifluoromethyl (CF₃: CF₃‐MI) made the peak patterns much simpler giving the copolymer with higher alternating sequence. More interestingly, the peak interval of the copolymer at earlier polymerization stage was equal to sum of the molecular weights of CF₃‐MI and styrene, suggesting possibility of the pair propagation of the monomers. Indeed, ¹H NMR analyses of the mixture of maleimide with styrene suggested stronger interaction of CF₃‐MI than EMI. Based on the results, maleimide derivatives carrying a substituent‐designable electron‐withdrawing group [ROC(?O)N–: R = substituent] were newly designed toward incorporation of functional side chains. They also gave higher alternating sequence for the copolymerization with styrene. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 367–375     

Role of monomer charge-transfer complexes in the free-radical copolymerization of styrene and fumarodinitrile

The equilibrium constant of the charge-transfer complex of styrene and fumarodinitrile was determined by ultraviolet and NMR measurements. Information about the role of the complex in the copolymerization of the two monomers could be obtained from copolymerization experiments at different monomer concentrations and temperatures. In addition, the influence of a second donor, anisole, was studied. The results show that in the copolymerization of styrene with fumarodinitrile addition of charge-transfer complexes has to be taken into account besides the addition of the free monomers.     

Kinetics of pseudoliving free-radical copolymerization of styrene and methyl methacrylate by the reversible addition fragmentation chain-transfer mechanism

The kinetics of copolymerization of styrene with methyl methacrylate in the presence of tert-butyl dithiobenzoate as a reversible addition fragmentation chain-transfer agent has been studied. Formation of radical intermediates has been investigated. In a wide range of monomer mixture compositions, the kinetic features of pseudoliving radical copolymerization of this monomer pair in the presence of both a low-molecular-mass reversible addition fragmentation chain-transfer (RAFT) agent and a polymer RAFT agent being formed are close to the corresponding features of the homopolymerization of styrene.     

Comparative recalculation of the monomer reactivity ratios in copolymerization for styrene and methyl methacrylate

The monomer reactivity ratios (MMRs) in radical copolymerization for styrene and methyl methacrylate were recalculated by five different methods using literature copolymerization data. The use of approximate 95% confidence limits and their visual inspection helps to separate possibly biased copolymer composition data. The recalculated mean MRR values were r₁ (styrene) = 0.501 ± 0.031 and r₂ = 0.472 ± 0.031. The results of the linear least-squares calculation procedures seldom approach the quality of the nonlinear least-squares analysis according to the method of Tidwell and Mortimer.     

Effect of monomer/nanoclay interaction on the kinetics of atom transfer radical homo- and copolymerization of styrene and methyl acrylate

Atom transfer radical homo- and copolymerization of styrene and methyl acrylate initiated with CCl₃-terminated poly(vinyl acetate) macroinitiator were performed at 90°C in the presence of nanoclay (Cloisite 30B). Controlled molecular weight characteristics of the reaction products were confirmed by GPC. It was shown that nanoclay slightly decreased the rate of styrene polymerization, while it significantly enhanced the rate of methyl acrylate polymerization and its copolymerization with styrene. The reactivity ratios of the monomers in the presence and in the absence of nanoclay were calculated (r _St = 1.002 ± 0.044, r _MA = 0.161 ± 0.018 by extended Kelen-Tudos method and r _St = 1.001 ± 0.038, r _MA = 0.163 ± 0.016 by Mao-Huglin method), confirming that the presence of nanoclay has no influence on monomer reactivity. The enhancement in the homopolymerization rate of methyl acrylate as well as its copolymerization rate with styrene was attributed to nanoclay effect on the dynamic equilibrium between active (macro)radicals and dormant species. Dipole moments of the monomers were successfully used to predict structure of the polymer/clay nanocomposites prepared via in situ polymerization.     

Preparation and properties of a methacrylate-containing siliconized epoxy hybrid monomer and its emulsion copolymerization with styrene/butyl acrylate

The objective of the present work was the synthesis and characterization of a methacrylate-containing siliconized epoxy hybrid monomer and its emulsion copolymerization in the presence of styrene/butyl acrylate monomers. The purity and structural conformation of this monomer were ascertained from FTIR and NMR spectral studies. Thermal properties of the copolymers were investigated by using differential scanning calorimetry and thermal gravimetric analysis. The morphology of copolymers was investigated by scanning electron microscopy and then the effect of siliconized epoxy hybrid monomer concentration on the water absorption ratio was examined. The results show that the water-resistance of the terpolymer films was higher compared with the films of styrene-co-butyl acrylate copolymer.     

Determination of reactivity ratios and kinetics of free radical copolymerization of linalool with styrene

Copolymerization of acyclic monoterpenoid, namely linalool (LIN), with styrene (STY) initiated by benzoyl peroxide (BPO) p‐acetyl benzylidene triphenyl arsonium ylide (p‐ABTAY) in xylene separately at 80°C for 180 min under inert atmosphere of nitrogen was performed. The results give a nearly alternating copolymer as evidenced from reactivity ratios (r₁ = 0.016, r₂ = 0.057) w.r.t. BPO; (r₁ = 0.017, r₂ = 0.052) w.r.t. p‐ABTAY (i.e. r₁ = 0.0165 ± 0.0005 and r₂ = 0.0545 ± 0.0025 per initiator set) using Kelen–Tudos method. The FT‐IR spectrum shows a band at 3026 cm^?1 due to the aromatic ring of polystyrene and an alcoholic band of linalool at 3408 cm^?1. ¹H‐NMR spectrum shows peaks at δ 7.0–7.7 ppm of ? OH protons and peaks at δ 7.5–8.0 ppm due to phenyl protons of styrene. The system follows ideal kinetics i.e. Rp ∝ [LIN]^1.0[STY]^1.0[BPO]^0.5/[p‐ABTAY]^0.5. The overall energy of activation in the temperature range 75–85°C is 77.0 kJ mol^?1 and 90.0 kJ mol^?1, respectively. The values for Mark–Houwink constants for the functional copolymer has been evaluated as a = 0.40 and K = 1.60 × 10^?4 with the help of gel permeation chromatography (GPC). Alfrey–Price, Q and e parameters for linalool have been evaluated as Q₂ = 0.80; e₂ = 1.25 w.r.t. BPO and Q₂ = 0.90; e₂ = 1.54 w.r.t. p‐ABTAY. Thermal properties of copolymers were investigated by thermogravimetric analysis (TGA) techniques. Copyright © 2004 John Wiley & Sons, Ltd.     

The temperature dependence of the monomer reactivity ratios in the copolymerization of styrene with α-substituted cinnamic acids

Styrene has been copolymerized with α-methyl [carboxyl-¹⁴C]cinnamic acid, α-phenyl [carboxyl-¹⁴C]cinnamic acid and ethyl benzylidene [carboxyl-¹⁴C]cyanoacetate at temperatures between 40 and 130°, using azoisobutyronitrile as initiator. The compositions of the copolymers have been determined by liquid scintillation counting; a simplified form of the copolymer composition equation was used to determine the reactivity ratios of the polystyryl radical. Arrhenius parameters have been derived. With the α-methyl and α-phenyl substituted acids, the pre-exponential factors favour self propagation, which predominates. With the smaller α-cyano substituent, self propagation is also favoured by the pre-exponential factors; however, cross propagation, favoured by the energies of activation, predominates. The effect of substitution by methyl or phenyl groups in the α-position of cinnamic acid is much greater than that found with the methyl or phenyl esters.     

Grafting copolymerization of styrene and maleic anhydride binary monomer systems induced by UV irradiation

Photografting copolymerization of maleic anhydride (MAH) and styrene (St) onto LDPE film was investigated by using a one-step method, and further thermally induced grafting copolymerization of them was carried out by using a two-step method. Regarding the photografting copolymerization of MAH/St binary monomer system, both conversion percentage (CP) and grafting efficiency (GE) increased with raising the content of MAH in the monomer feed. In addition, the content of MAH in the grafted copolymers also increased with increasing the fraction of MAH in the monomer feed. The formation of LDPE-g-P(MAH-co-St) grafted film was identified by FTIR and ESCA spectroscopy. In the case of grafting copolymerization of MAH/St by the two-step method, grafting copolymerization proceeded slowly compared with the non-grafting copolymerization. The apparent activation energy (E_a) for the non-grafting copolymerization in the solution and the grafting copolymerization on LDPE film was 24 and 82 kJ/mol, respectively, which were noticeably lower than those of MAH/vinyl acetate (MAH/VAC) binary monomer system under the similar grafting conditions. These data of E_a explained why the grafting copolymerization of styrene/MAH took place faster than that of MAH/VAC binary monomer system. The composition of the grafted copolymer chains was largely affected by the composition of the monomer feeds; however, the composition of the non-grafted copolymers nearly remained at 1/1 even in systems with largely different MAH/styrene ratios in monomer feeds. It is indicated that the non-grafting copolymerization proceeded predominantly following alternating copolymerization, but the grafting copolymerization performed random copolymerization.     

Radical copolymerization of styrene and alkyl methacrylates: monomer reactivity ratios and thermal properties

Copolymers containing styrene and alkyl methacrylate (n-butyl-, n-hexyl-, or stearyl methacrylate) at different compositions have been prepared by radical copolymerization. The monomer reactivity ratios were estimated using the Finemann-Ross, the inverted FR and the Kelen-Tüdos graphical methods. Structural parameters of the copolymers were obtained calculating the dyad monomer sequence fractions. The effect of the size of the alkyl methacrylate on the copolymer structure is discussed. The glass transition temperature, T_g of the copolymers with butyl and hexyl methacrylate was examined in the frame of several theoretical equations allowing the prediction of these T_g values. The best fit was obtained using methods that take into account the monomer sequence distribution of the copolymers. The copolymers of styrene with stearyl methacrylate exhibited the characteristic melting endotherm, due to the crystallinity of the methacrylate sequences and the polystyrene glass transition temperature.     

The temperature dependence of the monomer reactivity ratios in the copolymerization of styrene with methyl and ethyl cinnamates

Styrene (M₁) has been copolymerized with the methyl and the ethyl esters (M₂) of cinnamic acid (carboxyl ¹⁴C) at temperatures between 40 and 130°, using azoisobutyronitrile as initiator. The compositions of the copolymers have been determined by liquid scintillation counting; since [M₁ ? [M₂], a simplified form of the copolymer composition equation could be used for determining the reactivity ratio r₁ graphically. Arrhenius parameters have been derived; the energies of activation favour cross propagation whereas the frequency factors favour self propagation. Although the latter effect slightly predominates, there is no evidence of significant steric effects. These esters thus resemble cinnamic acid when copolymerized with styrene.Styrol (M₁) wurde bei Temperaturen zwischen 40 und 130° und AiBN als Initiator mit dem Methyl- und Äthylester (M₂) der Zimtsäure (¹⁴C-COO) copolymerisiert. Die Copolymerenzusammensetzung wurde durch Flüssigscintillation bestimmt. Für [M₁] ? [M₂] konnte eine vereinfachte Form der Copolymerisationsgleichung angewandt werden um r₁ graphisch zu bestimmen. Die Arrhenius-Parameter wurden abgeleitet; die Aktivierungsenergien begünstigen das gekreuzte Wachstum während die Hǎufigkeitsfaktoren das Eigenwachstum begünstigen. Obwohl der letztereEffekt leicht überwiegt, wurde kein Hinweis auf sterische Hinderung gefunden. In der Copolymerisation mit Styrol verhalten sich diese Ester wie die freie Zimtsäure.     

Influence of intrachain interactions on the kinetics of styrene polymerization and copolymerization

In the free-radical polymerization of styrene, it has been observed that the onset of an acceleration of the polymerization due to increased solution viscosity can be quantitatively measured as occurring at a critical point. The product of the degree of polymerization of the polymer in solution at the critical point times its volume fraction can be represented by a temperature-dependent constant (P?_n, V_c, = K ). The value of the constant passes through a maximum between 60 and 90°C. The value of the constant is somewhat lower than that for the phenomenon called chain entanglement. It is postulated that the temperature-dependent behavior of K is due to a previously reported solution phase transition which is believed to be caused by interaction between phenylgroups on the polystyrene chain. Observations on the ultraviolet absorbance of styrene copolymers and calculations on the absolute rate of copolymerization of styrene with methyl methacrylate are presented to support the postulated intrachain interactions.     

Study of the kinetics of styrene copolymerization with divinyl sulfide and the structure of macromolecules

The kinetics of the free-radical copolymerization of styrene with divinyl sulfide in the presence of N,N′-bis(vinyloxyethyl)thiuram disulfide as an iniferter has been studied. The rate of polymerization is shown to decrease with increasing iniferter concentration. The structure of the copolymers isolated in the course of copolymerization has been investigated by electron microscopy and compared with that of the copolymers synthesized using AIBN as an initiator. Evolution in the morphology of the polymer phase during the process, which consists in self-organization of the secondary supramolecular structure into spheroids with diameters of 0.1–10 μm, has been revealed. The stages of the formation of polymer particles of various structures are described by the scheme of morphogenesis.     

Living carbocationic copolymerization of isobutylene with styrene

The carbocationic copolymerization of isobutylene (IB) and styrene (St), initiated by 2‐chloro‐2,4,4‐trimethylpentane/TiCl₄ in 60/40 (v/v) methyl chloride/hexane at ?90 °C, was investigated. At a low total concentration (0.5 mol/L), slow initiation and rapid monomer conversion were observed. At a high total comonomer concentration (3 mol/L), living conditions (a linear semilogarithmic rate and M_n–conversion plots) were found, provided that the St concentration was above a critical value ([St]₀ ～ 0.6 mol/L). The breadth of the molecular weight distribution decreased with increasing IB concentration in the feed, reaching M_w/M_n ～ 1.1. St homopolymerization was also living at a high total concentration, yielding polystyrene with M_n = 82,000 g/mol, the highest molecular weight ever achieved in carbocationic St polymerization. An analysis of this system by both the traditional gravimetric–NMR copolymer composition method and FTIR demonstrated penultimate effects. IB enrichment was found in the copolymers at all feed compositions, with very little drift at a high total concentration and above the critical St concentration. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1778–1787, 2007     

High conversion copolymerization of styrene with methylmethacrylate

A study of the free radical copolymerization of styrene-methylmethacrylate at high conversion is reported. Differences are observed between the experimentally measured compositions and those calculated according to the integrated form of the copolymer composition equation, using published reactivity ratios. Significant differences occur only in situations exhibiting a gel effect, e.g. during bulk copolymerization or with a precipitant like butyl stearate present. Negligible differences are exhibited when a solvent such as benzene is present. Differences have been expressed as changes in copolymer reactivity ratios with conversion; the start of any changes in reactivity ratios is closely related to the onset of gel effects.     

Radical copolymerization of crotonyl compounds with styrene

The monomer reactivity ratios for the radical copolymerization of crotononitrile (CN), methyl crotonate (MC), and n-propenyl methyl ketone (PMK) with styrene (St) were measured at 60°C. in benzene and little penultimate unit effect was shown for these systems. The values obtained were: St–CN, r₁ = 24.0, r₂ = 0; St–MC, r₁ = 26.0, r₂ = 0.01; St–PMK, r₁ = 13.7, r₂ = 0.01. The rate of copolymerization and the viscosity of the copolymer decreased markedly as the molar fraction of the crotonyl compound in the monomer mixture increased. The Q–e values were also calculated to be as follows: CN, e = 1.13, Q = 0.009; MC, e = 0.36, Q = 0.015; PMK, e = 0.61, Q = 0.024. A linear relationship was obtained between the e values of the crotonyl compounds and their Hammett constants σ_m.     

Emulsion copolymerization of styrene with a nonionic styrenic polymerizable surfactant

Among the variety of possible structures for polymerizable surfactants, it seems clear that the most interesting should be those with the reactive group located in the hydrophobic part of the molecule. We report here a study based on such a surfactant. Its general formula is A set of surfactants has been produced with m varying from 23 to 48 and n = 6 or 12. The compounds have been characterised by ¹H-NMR (nuclear magnetic resonance), size exclusion chromatography, surface tension measurements and turbidimetry. These surfactants have been copolymerized with styrene in emulsion polymerization. The coagulum is rather important, except if m is large enough. Although the incorporation of the surfactant in the latex is rather high. Most of the anchored surfactant remains at the surface and is not too buried inside. The particle size decreases with both the amount of surfactant and the length of its hydrophilic part. The use of these polymerizable surfactants leads to an excellent stability of the latex against the addition of electrolytes, and also against freeze-thawing constraints.