Vinyl polymerization initiated by peroxydiphosphate

Colloid and Polymer Science - The kinetics of aqueous polymerization of acrylamide and methacrylamide initiated by potassium peroxydiphosphate has been investigated. The kinetic orders with respect...     

Vinyl polymerization initiated by peroxydiphosphate

The kinetics of the aqueous polymerization of acrylonitrile and methyl methacrylate initiated by the peroxydiphosphate-thioglycollic acid redox system was investigated at 40, 45, 50, 55, and 60 °C. The rates of polymerization were measured at different concentrations of oxidant, activator and monomer. From the results, it was concluded that the polymerization reaction is initiated by an organic free radical arising from the peroxydiphosphate-thioglycollic acid system and termination by mutual type. On the basis of experimental observations of the dependence of the rate of polymerization,R _p on various variables, a suitable kinetic scheme has been proposed.     

Vinyl polymerization by metal complexes. III. Vinyl polymerization initiated by oligoamide and cupric ion system

Polymerization of methyl methacrylate and other vinyl monomers was studied in the presence of oligoamide (?-aminocaproic acid, its dimer, trimer, tetramer, and pentamer) and cupric ion in aqueous media. The polymerization was found to be of free-radical character and selective for the type of vinyl monomer. Carbon tetrachloride can accelerate the polymerization. The initiation mechanism of the polymerization is discussed. Spectroscopic measurements were indicative of formation of 1:1 complex between oligoamides and cupric ion in aqueous NaClO₄ solution. Some chemical and physical properties of the resulting polymers were measured.     

Vinyl polymerization initiated by system of organic halides and tertiary amines

A study of the polymerization of vinyl monomers with binary systems of tertiary amines and various organic halides containing chemical bonds such as C? Cl, N? Cl, O? Cl, S? Cl, and Si? Cl has been made at 60°C. Some of the binary systems were found to be effective as radical initiator in the polymerization of methyl methacrylate. The relative initiating activities of the halides in the presence of dimethylaniline were found to be in the following order: tert-C₄H₉OCl > n-C₄H₉NCl₂ > (n-C₄H₉)₂NCl ? CH₃SiCl₃ ? C₆H₅SiCl₃ > C₆H₅SO₂Cl > C₆H₅Cl > C₆H₅PCl₂. Styrene and vinyl acetate polymerized only with the initiator system of dimethylaniline and benzyl chloride. Tri-n-butylamine was less active than dimethylaniline. Pyridine and 4-vinylpyridine, in combination with some organic halides, also initiated the polymerization of methyl methacrylate. The N-vinylcarbazole–benzenesulfonyl chloride system, in the presence of methyl methacrylate, gave only the homopolymer of N-vinylcarbazole.     

Vinyl polymerization of acrylamide initiated by Thallium(III) ions in solution

Kinetics of polymerization of acrylamide initiated by Thallium(III) perchlorate was investigated in aqueous perchloric acid medium in the temperature range of 55–70°C. The rates of polymerization were measured varying the concentration of the monomer, initiator, and perchloric acid. The rate of polymerization was found to increase with increase of temperature, monomer concentration, initiator concentration, and perchloric acid concentration. The effect of additives like different solvents, surfactants, and retarders on the rate of polymerization was studied. Molecular weights of the polymer were determined by viscometry. The chain transfer constants for the monomer (C_M) and that for the solvent dioxan (C_s) were calculated to be 7.33 × 10^?3 and 6.66 × 10^?3, respectively. From the Arrhenius plot, the overall activation energy (E_a) was calculated to be 10.68 kcal/mol. The energy of initiation was calculated to be 12.36 kcal/mol. Depending on the results obtained, a suitable reaction mechanism has been suggested and a rate equation has been derived.     

Vinyl polymerization initiated by peroxydiphosphate—VI: Polymerization of acrylonitrile initiated by peroxydiphosphate-Mn(II) and peroxydiphosphate-Fe(II) redox systems

Acrylonitrile was polymerized using peroxydiphosphate-Fe(II) and peroxydiphosphate-Mn(II) redox systems within the range 40–60°. The kinetic orders with respect to peroxydiphosphate, metal ion and monomer were close to 0.5, 0.5 and 1.0, respectively. Overall activation energies were computed and a suitable kinetic scheme suggested.     

Vinyl polymerization initiated by peroxydiphosphate. VII. Polymerization of acrylonitrile initiated by peroxydiphosphate–ascorbic acid redox system

The polymerization of acrylonitrile was studied with a peroxydiphosphate–ascorbic acid redox system as the initiator. The rate of polymerization increased with increasing peroxydiphosphate concentration and the initiator exponent was computed to be 0.5. It also increased with increasing monomer concentration and the monomer exponent was computed to be unity. The reaction was carried out at three different temperatures and the overall activation energy was computed to be 4.6 kcal/mol. The effect of certain surfactants on the rate of polymerization was investigated and a suitable kinetic scheme is described.     

Vinyl polymerization of acrylonitrile by the Ce(IV)-glucose redox system

Aqueous polymerization of acrylonitrile (M) initiated by the Ce(IV)-glucose (R) redox system has been studied under nitrogen in the temperature range of 30–40 °C. The rate of polymerization (Rp) is proportional to [M]², [R] and inversely proportional to [Ce(IV)]. The rate of ceric ion disappearance is proportional to [R] and [Ce(IV)]. The end group in the polymer is characterised by IR spectra. A suitable kinetic scheme has been proposed and explained in the light of these experimental findings.     

Vinyl polymerization initiated by peroxydiphosphate. V. Polymerization of acrylonitrile initiated by peroxydiphosphate-cyclohexanol redox system in the presence of silver ion

The polymerization of acrylonitrile was carried out using peroxydiphosphate-cyclohexanol redox system in the presence of silver ion. The rate of polymerization increases with increasing peroxydiphosphate concentration and the initiator exponent was computed to be 0.5. The rate of polymerization increases with increasing monomer concentration and the monomer exponent was computed to be unity. The plot of R_p vs [Ag⁺]^1/2 was linear, indicating 0.5 order with respect to [Ag⁺]. The reaction was carried out at three different temperatures and the overall activation energy was calculated to be 7.60 kcal/mol. The effect of certain surfactants on the rate of polymerization has been investigated and a suitable kinetic scheme has been pictured.     

Vinyl polymerization. 413. Polymerization of vinyl monomer initiated by poly(vinylbenzyltrimethyl)-ammonium chloride

The polymerization of vinyl monomer initiated by an aqueous solution of poly(vinylbenzyltrimethyl)ammonium chloride (Q-PVBACI) was carried out at 85°C. Styrene, p-chlorostyrene, methyl methacrylate, and i-butyl methacrylate were polymerized, whereas acrylonitrile and vinyl acetate were not. The effects of the amounts of vinyl monomer, Q-PVBACI, and water on the conversion of vinyl monomer were studied. The overall activation energy in the polymerization of styrene was estimated as 79.1 kJ mol^?1. The polymerization proceeded through a radical mechanism. The selectivity of vinyl monomer was discussed by “a concept of hard and soft hydrophobic areas and monomers.”     

Vinyl polymerization initiated by chromic acid–reducing agent systems

A kinetic study of the thermal polymerization of acrylonitrile initiated by chromic acid–reducing agent (n-butanol, ethylene glycol, cyclohexanone, and acetaldehyde) systems was made. Chromic acid alone did not initiate polymerization under deaerated or undeaerated conditions. On the basis of the experimental determination of the dependencies of various variables on the rate of polymerization R_p, the rate of chromium (VI) disappearance ?R_M, the degree of polymerization DP, etc., a reasonable kinetic scheme was arrived at. The mechanism with the reducing agents, n-butanol, cyclohexanone, and ethylene glycol, was found to be similar but different from that with acetaldehyde. Evidence has been presented to prove the formation of radical intermediates formed by the oxidation of the reducing agent by Cr(IV). Rate parameters for oxidation of the reducing agent and polymerization of the monomer were evaluated.     

Vinyl polymerization of acrylonitrile by the cerium(IV)-propane-1,2-diol system

The polymerization of acrylonitrile (M) initiated by the Ce(IV)-propane-1,2-diol (R) redox system has been studied in aqueous sulphuric acid under nitrogen in the temperature range 30 to 40°. The rate of polymerization is proportional to [M]², [R] and [Ce(IV)]^?1 and the rate of ceric ion disappearance is proportional to [R], [Ce(IV)]. The effects of certain salts, acid, solvent and temperature on both rates have been investigated. A kinetic scheme has been proposed, and various rate and energy parameters evaluated.     

Vinyl polymerization. 416. Polymerization of vinyl monomer initiated by polyethyleneglycol

The polymerization of vinyl monomer initiated by polyethyleneglycol (PEG) in aqueous solution was carried out at 85°C with shaking. Acrylonitrile (AN), methyl methacrylate (MMA), and methacrylic acid were polymerized by PEG–300 (M?_n = 300), whereas styrene was not. The effects of the amounts of monomer and PEG, the molecular weight of PEG, and the hydrophobic group at the end of PEG molecule on the polymerization were studied. The selectivity of vinyl monomer and the effect of the hydrophobic group are discussed according to “the concept of hard and soft hydrophobic areas and monomers.” The kinetics of the polymerization was investigated. The overall activation energy in the polymerization of AN was estimated as 37.9 kJ mol^?1. The polymerization was effected by a radical mechanism.     

Vinyl polymerization by a manganese(III) complex

Bis(diethanolamine) manganate(III) was prepared. The polymerization of acrylamide and methacrylamide initiated by this complex in aqueous solution at pH 0.9 was studied at 45°. The rate of polymerization was followed by bromometry, the rate of complex disappearance spectrophotometrically and the molecular weights of the polymers were determined viscometrically. The rate of polymerization was found to be proportional to [Monomer]^1.0. The order with respect to initiator was found to be 0.5 for acrylamide and 0.3 for methacrylamide. The apparent overall activation energies for the polymerizations are ?87 kJ mol^?1 and ?59 kJ mol^?1 for acrylamide and methacrylamide respectively. A kinetic reaction scheme is proposed on the basis of the experimental data; kinetic parameters have been evaluated.     

Vinyl polymerization. Part 268. Polymerization of acrylonitrile initiated by the system of tetramethyl tetrazene and bromoacetic acid

The polymerization of acrylonitrile (AN) initiated by the system of tetramethyl tetrazene (TMT) and bromoacetic acid (BA) in dimethylformamide (DMF) was studied. The TMT–BA system could initiate the polymerization of AN more easily than TMT alone. The polymerization was confirmed to proceed through a radical mechanism. The initial rate of polymerization R_p was expressed by the equation: R_p = [TMT]^0.62-[BA]^0.5[AN]^1.5. The overall activation energy for the polymerization was estimated as 9.4 kcal/mole. In the absence of monomer, the reaction of TMT with BA in DMF was also studied kinetically by measuring the evolution of nitrogen gas. The reaction was first-order in TMT and first-order in BA; the rate data at 49°C were k₂ = 9.1 × 10^?2l./mole-sec., ΔH? = 17.0 kcal/mole, and ΔS? = ? 6.6 eu. In addition, the treatment of TMT with BA in benzene led to the formation of tetramethylhydrazine radical cation, which was identified by its ESR spectrum. On the other hand, the relatively strong interaction between TMT and DMF was observed by absorption spectrophotometry.     

Vinyl polymerization initiated by ceric ion reducing agent systems in sulfuric acid medium

Polymerization of the monomers, methyl acrylate (MA) and methyl methacrylate (MMA) was carried out in sulfuric acid medium at 15°C. With the redox initiator system, ceric ammonium sulfate–malonic acid. There was no induction period, and a steady state was attained in a short time. There was found to be no polymerization even after 1 hr. in the absence of the reducing agent R. The initiation was by the radical produced from the Ce⁴⁺–malonic acid reaction. The rate of monomer disappearance was proportional to [M]^1.5, [R]^0.5, and [Ce⁴⁺]^0.3–0.5, and the rate of ceric disappearance was directly proportional to [R] and [Ce⁴⁺]. Chain lengths of the polymers were directly proportional to [M] and inversely to [R]^1/2 and [Ce⁴⁺]^1/2. The experimental results were explained by a kinetic scheme involving the following steps: (a) oxidation of the substrate to give the primary radical which reacts with Ce⁴⁺ to give the products, (b) initiation by the primary radical, (c) propagation, and (d) termination of the growing polymer radicals by the mutual type. For the polymerization of acrylonitrile (AN) by the redox system, ceric ammonium sulfate–cyclohexanone (CH), in sulfuric acid at 15°C., the scheme was modified to include linear type of termination by Ce⁴⁺, along with the mutual termination to explain the results especially under conditions with [Ce⁴⁺] ≥ [CH].