Grafting. III. Copolymerization of methyl methacrylate and methacrylic acid

The method of graft copolymerization of methyl methacrylate on halogen-containing polymer has been utilized for grafting of methyl methacrylate–methacrylic acid monomer pair onto poly(vinyl chloride) and chlorinated rubber. Substantial grafting could be obtained by using the method reported earlier. However, the compositions of the grafted chains are found to deviate appreciably from the compositions calculated from r₁ and r₂ values reported in literature. The reactivity ratios for this pair of monomers have been therefore evaluated using azobisisobutyronitrile and n-butane thiol–dimethyl sulfoxide as initiators. The anomalies of the grafted chain compositions have been discussed and an explanation presented on preferential solvation.     

Bulk and solution copolymerization of methyl methacrylate and vinyl acetate

A series of batch, bulk and solution (in toluene) copolymerizations of methyl methacrylate and vinyl acetate was performed under various reaction conditions to high monomer conversions. In addition, low conversion bulk experiments were performed to estimate monomer reactivity ratios using the error in variables model method, based on terminal model (Mayo–Lewis) kinetics. A combination of the low and high conversion data with data from a previous study yielded reactivity ratio (r) estimates of 27.465 and 0.0102 for r_MMA and r_VAc, respectively, using the integrated copolymer composition (Meyer–Lowry) equation. In the high conversion experiments the effects of various factors on the reaction rate, cumulative copolymer composition, number‐ and weight‐average molecular weights, and molecular weight distribution were studied. The factors included the monomer feed composition, initiator concentration, temperature, solvent concentration, and the addition of n‐dodecyl mercaptan chain transfer agent. These factors were examined in light of the wide difference in the monomer reactivity ratios. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1238–1255, 2001     

Modeling and experimental studies of emulsion copolymerization systems. III. Acrylics

Using a previously published model and continuing the series of papers started with styrenic copolymers, predictions for evolution of conversion and average particle diameter in batch experiments are compared against experimental data for four emulsion copolymerizations involving at least one acrylic monomer: (1) methyl methacrylate/butyl acrylate, (2) methyl methacrylate/butadiene, (3) methyl methacrylate–vinyl acetate, and (4) butyl acrylate/vinyl acetate. For each system a fraction of factorial experiments were run covering simultaneous variations in five variables: initiator [I] and surfactant [E] concentrations, water to monomer ratio (W/M), monomer composition, and temperature. Data fitting is performed to represent the experimental data as several parameters are not available from independent experimental sources. The model is able to explain the effects of simultaneous changes in emulsifier concentration, initiator concentration, and water to monomer ratio on conversion and average particle size histories, although in some cases only qualitatively. An assessment of the degree in which a general emulsion copolymerization model is useful for practical applications is made. Physical insight is also gained by observing the trends of adjusted parameters with temperature and copolymer composition. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1320–1338, 2002; DOI 10.1002/app.10003     

Organotin polymers. IX. Copolymerization parameters of di-(tri-n-butyltin) itaconate with styrene and methyl methacrylate

Copolymerization reactions of di-(tri-n-butyltin) itaconate with styrene and methyl methacrylate were carried out in solution at 70°C using 1 mol% azobisisobutyronitrile as a free radical initiator. The copolymer compositions were determined by chemical analysis as well as from ¹H-NMR data. The monomer reactivity ratios for copolymerizations of di-(tri-n-butyltin) itaconate with styrene and methyl methacrylate have been found to be r₁ = 0.228, r₂ = 0.677, and r₁ = 0.220, r₂ = 1.635, respectively. The sequence distribution of the triad fractions were calculated from reactivity ratios and compared with those obtained from ¹H-NMR data.     

Organotin polymers-V. Binary and ternary copolymerization reactions of tributyltin acrylate and methacrylate with vinyl acetate and N-vinylpyrrolidone

Copolymerization reactions were carried out in solution at 70°C in the presence of a free radical initiator, and the copolymer composition in each case was determined from tin analysis. The monomer reactivity ratios for the copolymerization reactions of tributyltin acrylate with vinyl acetate and N-vinylpyrrolidone were found to be: r₁ = 2.567, r₂ = 0.006 and r₁ = 0.513, r₂ = 0.610, respectively. Also, the copolymerization parameters of tributyltin methacrylate with vinyl acetate and N-vinylpyrrolidone were: r₁ = 4.408, r₂ = 0.017 and r₁ = 3.160, r₂ = 0.438, respectively. Four selected terpolymer feed compositions involving tributyltin acrylate or methacrylate with vinyl acetate or methyl methacrylate and N-vinylpyrrolidone or acrylonitrile, were polymerized to low conversion and the terpolymer composition in each case was calculated from tin and nitrogen analyses. The variations of terpolymer composition with conversion fit the experimental results over a wide range of conversion. The structure of the prepared co- and terpolymers was investigated by i.r. spectroscopy.     

Graft polymerization of vinyl acetate onto starch. Saponification to starch–g–poly(vinyl alcohol)

Graft polymerizations of vinyl acetate onto granular corn starch were initiated by cobalt-60 irradiation of starch-monomer-water mixtures, and ungrafted poly(vinylacetate) was separated from the graft copolymer by benzene extraction. Conversions of monomer to polymer were quantitative at a radiation dose of 1.0 Mrad. However, over half of the polymer was present as ungrafted poly-(vinyl acetate) (grafting efficiency less than 50%), and the graft copolymer contained only 34% grafted synthetic polymer (34% add-on). Lower irradiation doses produced lower conversions of monomer to polymer and gave graft copolymers with lower % add-on. Addition of minor amounts of acrylamide, methyl acrylate, and methacrylic acid as comonomers produced only small increases in % add-on and grafting efficiency. However, grafting efficiency was increased to 70% when a monomer mixture containing about 10% methyl methacrylate was used. Grafting efficiency could be increased to over 90% if the graft polymerization of vinyl acetate-methyl methacrylate was carried out near 0°C, although conversion of monomers to polymer was low and grafted polymer contained 40-50% poly(methyl methacrylate). Selected graft copolymers were treated with methanolic sodium hydroxide to convert starch–g–poly(vinyl acetate) to starch–g–poly(vinyl alcohol). The molecular weight of the poly(vinyl alcohol) moiety was about 30,000. The solubility of starch–g–poly(vinyl alcohol) in hot water was less than 50%; however, solubility could be increased by substituting either acid-modified or hypochlorite-oxidized starch for unmodified starch in the graft polymerization reaction. Vinyl acetate was also graft polymerized onto acid-modified starch which had been dispersed and partially solubilized by heating in water. A total irradiation dose of either 1.0 or 0.5 Mrad gave starch–g–poly(vinyl acetate) with about 35% add-on, and a grafting efficiency of about 40% was obtained. A film cast from a starch–g–poly(vinyl alcohol) copolymer in which homopolymer was not removed exhibited a higher ultimate tensile strength than a comparable physical mixture of starch and poly(vinyl alcohol).     

Organotin polymers. VII. Copolymerization of triphenyltin methacrylate with some acrylic and methacrylic acid esters

The monomer reactivity ratios for the copolymerization of triphenyltin methacrylate with methyl acrylate, ethyl acrylate, and butyl acrylate have been found to be r₁ = 2.58, r₂ = 0.66, r₁ = 2.37, r₂ = 0.43, and r₁ = 1.27, r_0.39 = 0.39, respectively. also, the copolymerization parameters of triphenyltin methacrylate with methyl methacrylate and butyl methacrylate were as follows: r₁ = 0.94, r₂ = 0.99, and r₁ = 0.68, r₂ = 0.83, respectively. Copolymerization reactions were carried out in solution at 70°C using 1 mol % AIBN, and the copolymer compositions were determined by tin analysis. The sequence distribution of the alternating diad fractions for the systems studied were calculated at various feed compositions. The structure of the triphenyltin methacrylate monomer as well as its azeotropic copolymer with butyl methacrylate were investigated by IR spectroscopy.     

Polymerization of an Acetoxyvinyl Substituted Chlorocyclophosphazene

The vinyl acetate derivative, gem-isopropyl-2-(-acetoxyvinyl)tetrachlorocyclotriphosphazene (1), has been used in radical homopolymerization and copolymerization reactions with methyl methacrylate, (MMA) and styrene. The 1,1-disubstituted olefin did not undergo radical homopolymerization. Copolymers derived from MMA and 1 contained only low amounts (<2 mol%) of 1. A maximum incorporation of 20 mol% of phosphazene monomer was achieved with styrene as comonomer. The data obtained in low- and high-conversion copolymerizations with styrene were used to calculate the monomer reactivity ratios. The results of the calculations show that the terminal model is not operative. Calculation for the penultimate model with r ₂=0 resulted in r ₁ and r₁ values of 2.8±0.2 and 0.7±0.1, respectively. For the hypothetical homopolymer of 1 a T _g value of 441 K was calculated. All the copolymers with styrene exhibit flame-retardant properties.     

Conventional and RAFT miniemulsion copolymerizations of butyl methacrylate with fluoromethacrylate and monomer reactivity ratios

Reversible addition fragmentation chain transfer (RAFT) mediated and conventional miniemulsion copolymerizations of butyl methacrylate (BMA) with fluoromethacrylate (FMA) were carried out at 70°C with potassium persulphate as initiator. The kinetics of the copolymerizations was investigated comparatively. Copolymer compositions at low conversion levels were determined by ¹H NMR and FTIR spectra techniques. In the presence of RAFT agent 2‐cyanoprop‐2‐yl dithiobenzoate, the copolymerization of BMA with FMA in miniemulsion was obviously retarded. The copolymerization exhibited typical features of controlled molecular weights and narrow polydispersities. The reactivity ratios were evaluated by Kellen‐Tudos (K‐T) method, which yields the apparent reactivity ratios: r_BMA = 0.73 and r_FMA = 0.75 in conventional copolymerizations, and r_BMA = 0.65 and r_FMA = 0.70 in CPDB‐mediated system. The results show that the monomer FMA with a perfluoroalkyl side chain is slightly more reactive than BMA, and the copolymerizations process have a tendency to crosspropagate and to produce a higher FMA content in the copolymers. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Synthesis and characterization of methyl methacrylate/styrene hyperbranched copolymers via living radical mechanism

Free‐radical copolymerizations of N,N‐diethylaminodithiocarbamoylmethylstyrene (inimer: DTCS) with a methyl methacrylate (MMA)/zinc chloride (ZnCl₂) complex were carried out under UV light irradiation. DTCS monomers play an important role in this copolymerization system as an inimer that is capable of initiating living radical polymerization of the vinyl group. The reactivity ratios (r₁ = 0.56 and r₂ = 0.52: DTCS [M₁]; MMA [M₂]) obtained for this copolymerization system were different from a corresponding model system (alternating copolymer) of a styrene and MMA/ZnCl₂ complex (r₁ = 0.25 and r₂ = 0.056). It was found that the hyperbranched copolymers produced exhibited a random branching structure. It was found that the Lewis acid ZnCl₂ formed the complex not only with MMA but also with the carbamate group of inimer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2490–2495, 2003     

Synthesis and characterization of poly(vinyl chloride‐co‐vinyl acetate)‐graft‐poly[(meth)acrylates] by atom transfer radical polymerization

The graft polymerization of methyl methacrylate and butyl acrylate onto poly(vinyl chloride‐co‐vinyl acetate) with atom transfer radical polymerization (ATRP) was successfully carried out with copper(I) thiocyanate/N,N,N′,N′,N″‐pentamethyldiethylenetriamine and copper(I) chloride/2,2′‐bipyridine as catalysts in the solvent N,N‐dimethylformamide. For methyl methacrylate, a kinetic plot of ln([M]₀/[M]) (where [M]₀ is the initial monomer concentration and [M] is the monomer concentration) versus time for the graft polymerization was almost linear, and the molecular weight of the graft copolymer increased with increasing conversion, this being typical for ATRP. The formation of the graft polymer was confirmed with gel permeation chromatography, ¹H‐NMR, and Fourier transform infrared spectroscopy. The glass‐transition temperature of the copolymer increased with the concentration of methyl methacrylate. The graft copolymer was hydrolyzed, and its swelling capacity was measured. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 183–189, 2005     

The preparation of some block copolymers

The reactivity of the double bonds in p-divinylbenzene toward anionic reagents is much greater than is the residual double bond in the divinylbenzene unit incorporated in a polymer chain. Thus it is possible to add to a “living” polymer a few divinylbenzene units before appreciable crosslinking occurs. Each of these units will have a vinyl group conjugated with a phenyl ring and will be comparable in reactivity to styrene. If the reaction is stopped at this point by the addition of methanol, the molecular weight of the product is essentially that of the original living polymer. These polymers may then be copolymerized through these active double bonds with any monomer with which styrene may be copolymerized, to form block or graft-like copolymers. The copolymerizations may be effected by any of the methods applicable to styrene, i.e., free radical, cationic, or anionic. Such copolymerizations have been attempted with methyl methacrylate, butyl acrylate, vinyl chloride, vinylidene chloride, vinyl acetate, butadiene, isobutene, and propene, usually successfully.     

Study of the Copolymerization Parameters of 2-Thiozyl Methacrylamide with Different Alkyl Acrylates

2-thiozyl methacrylamide (TMA) was synthesized by the reaction of 2-aminothiazole with either methacryloyl chloride or methacrylic acid in the presence of triethylamine and N, N′-dicyclohexylcarbodiimide, respectively. Binary copolymerization reactions of the prepared monomer with methyl acrylate (MA), ethyl acrylate (EA), n-butyl acrylate (BA) and tert-butylacrylate (t.BA) were performed in dimethylformamide at 65^○C using 1 mol% azobisisobutyronitrile (AIBN) as initiator. The structure of the 2-thiozyl methacrylamide monomer and the prepared copolymers was investigated by IR and ¹H NMR spectroscopy. The copolymer compositions were determined from sulphur analysis. Copolymerization parameters for each system were calculated by the Finemen–Ross and Kelen–Tüdös methods. The monomer reactivity ratios for the systems TMA-MA, TMA-EA, TMA-BA, and TMA-tBA were found to be r₁=0.128, r₂=0.740; r₁=0.235, r₂=0.420; r₁=0.420, r₂=0.330 and r₁=1.690, r₂=0.027, respectively. The reactivities of acrylic esters decrease as the alkyl group become bulkier. The average Q and e values for TMA were calculated from the monomer reactivity ratios determined in the present and previous studies.     

Determination of monomer reactivity ratios in copolymerizations with N-vinylpyrrolidone by means of high-speed liquid chromatography

High-speed liquid chromatography was applied to the studies of the polymerization of N-vinylpyrrolidone and its copolymerizations with vinyl acetate, glycidyl methacrylate and methyl methacrylate. The conversion was calculated from the decrease in peak-height in the chromatogram of the monomer. A small change in the amount of monomer was closely determined by using o-diphenyl benzene (o-terphenyl) as an internal standard. The calculations of the monomer reactivity ratios gave concordant results with those reported earlier. The obtained copolymer compositions agreed with the data by elementary analysis. The application of high-speed liquid chromatography to the determination of copolymerization reactivity ratios was thus found to be advantageous for saving time. The monomer reactivity ratio can be determined without the complicated processings such as separating, drying and analysing the copolymers.     

Photophysical studies of copolymers of N‐vinylcarbazole

The absorption, fluorescence excitation and emission spectroscopy, and time‐dependent spectrofluorimetry have been used to study the photophysics of copolymers of N‐vinylcarbazole with different monomers like vinyl acetate, methyl acrylate, methyl methacrylate, butyl acrylate, and butyl methacrylate in dichloromethane. In all the copolymers and at different N‐vinylcarbazole content, the absorption spectra reflect only the monomer carbazole units. The two kinds of excited monomer species of N‐vinylcarbazole are present in S₁ state. Short‐lived (～3 ns) excited monomer decays forming low energy excimer obtained by the complete overlap of the excited carbazole monomer. The long‐lived excited monomer (～8 ns) decays to ground state without formation of any excimer. The high energy excimer is relatively short‐lived and is formed by the partial overlap of the carbazole units. The presence of bulky group in the copolymer chain hinders the formation of excimers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 372–380, 2006     

Reactivity ratios and copolymer properties of 2‐(diisopropylamino)ethyl methacrylate with methyl methacrylate and styrene

Free radical copolymerization kinetics of 2‐(diisopropylamino)ethyl methacrylate (DPA) with styrene (ST) or methyl methacrylate (MMA) was investigated and the corresponding copolymers obtained were characterized. Polymerization was performed using tert‐butylperoxy‐2‐ethylhexanoate (0.01 mol dm^?3) as initiator, isothermally (70 °C) to low conversions (<10 wt%) in a wide range of copolymer compositions (10 mol% steps). The reactivity ratios of the monomers were calculated using linear Kelen–Tüd?s (KT) and nonlinear Tidwell–Mortimer (TM) methods. The reactivity ratios for MMA/DPA were found to be r₁ = 0.99 and r₂ = 1.00 (KT), r₁ = 0.99 and r₂ = 1.03 (TM); for the ST/DPA system r₁ = 2.74, r₂ = 0.54 (KT) and r₁ = 2.48, r₂ = 0.49 (TM). It can be concluded that copolymerization of MMA with DPA is ideal while copolymerization of ST with DPA has a small but noticeable tendency for block copolymer building. The probabilities for formations of dyad and triad monomer sequences dependent on monomer compositions were calculated from the obtained reactivity ratios. The molar mass distribution, thermal stability and glass transition temperatures of synthesized copolymers were determined. Hydrophobicity of copolymers depending on the composition was determined using contact angle measurements, decreasing from hydrophobic polystyrene and poly(methyl methacrylate) to hydrophilic DPA. Copolymerization reactivity ratios are crucial for the control of copolymer structural properties and conversion heterogeneity that greatly influence the applications of copolymers as rheology modifiers of lubricating oils or in drug delivery systems. © 2015 Society of Chemical Industry     

Atom transfer radical polymerization of methyl methacrylate initiated with a macroinitiator of poly(vinyl acetate)

Well‐defined poly(vinyl acetate‐b‐methyl methacrylate) block copolymers were successfully synthesized by the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in p‐xylene with CuBr as a catalyst, 2,2′‐bipyridine as a ligand, and trichloromethyl‐end‐grouped poly(vinyl acetate) (PVAc–CCl₃) as a macroinitiator that was prepared via the telomerization of vinyl acetate with chloroform as a telogen. The block copolymers were characterized with gel permeation chromatography, Fourier transform infrared, and ¹H‐NMR. The effects of the solvent and temperature on ATRP of MMA were studied. The control over a large range of molecular weights was investigated with a high [MMA]/[PVAc–CCl₃] ratio for potential industry applications. In addition, the mechanism of the polymerization was discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1089–1094, 2006     

On-line GPC/NMR analyses of block and random copolymers of methyl and butyl methacrylates prepared with t-C4H9MgBr

Summary The isotactic block and random copolymers of methyl methacrylate and butyl methacrylate prepared with t-C₄H₉MgBr in toluene, were analyzed by using a 500 MHz ¹H NMR spectrometer as a detector of gel permeation chromatography. The molecular weight dependence of the chemical compositions of these copolymers could be directly determined with this method by monitoring signal intensities of OCH₃ and OCH2 due to methyl methacrylate and butyl methacrylate units, respectively. From the results mechanism of the copolymerizations was discussed in some detail.     

Radical polymerization and copolymerization behavior of 1-cyanoethanoyl-4-acryloylthiosemicarbzide

1-Cyanoethanoyl-4-acryloylthiosemicarbazide (CEATS) was synthesized for the first time as a new chelating monomer. Its structure was confirmed by both elemental and spectral analyses. Radical polymerization and copolymerization of CEATS was been carried out in dimethylformamide (DMF) in the presence of azobisisobutyronitrile (AIBN) as an initiator. Kinetic studies for the polymerization behavior of CEATS were performed. The complex formation of the CEATS monomer and polymer (PCEATS) with Cu II cation was investigated and its stability constant determined. The rate of copolymerization of CEATS with some conventional monomers, namely vinyl acetate, methyl methacrylate and acrylonitrile, was measured as a function of the mole fraction of the monomers. The reactivity ratios (r₁, r₂) for the various copolymer systems investigated together with the Q and e values of the CEATS monomer were determined. Moreover, the thermal gravimetric analysis of the prepared polymers and their copolymers with acrylonitrile were also studied.     

Organotin polymers. IV. Binary and ternary copolymerizations of tributyltin acrylate and methacrylate with styrene,allyl methacrylate,butyl methacrylate,butyl acrylate,and acrylonitrile

The monomer reactivity ratios for the copolymerization of tributyltin acrylate with styrene and allyl methacrylate have been found to be r₁ = 0.213, r₂ = 1.910 and r₁ = 0.195, r₂ = 2.257, respectively. Also, the copolymerization parameters of tributyltin methacrylate with styrene and allyl methacrylate were as follows: r₁ = 0.256, r₂ = 1.104 and r₁ = 2.306, r₂ = 1.013. Copolymerization reactions were carried out in solution at 70°C using 1 mole % AIBN, and the copolymer compositions were determined by tin analysis. Ternary copolymerization of the three systems butyl methacrylate–tributyltin methacrylate–acrylonitrile, butyl acrylate–tributyltin methacrylate–acrylonitrile, and styrene–tributyltin acrylate–acrylonitrile have been studied, and the terpolymer composition of each system was determined through tin and nitrogen analyses. The variation of instantaneous and average terpolymer composition with conversion fit satisfactorily the experimental results over a wide range of conversion.