Photoinitiated homopolymerization and copolymerization of furfuryl methacrylate and N-vinylpyrrolidone

The study of the homo- and copolymerization of furfuryl methacrylate ( F ) and vinylpyrrolidone ( P ) in bulk, initiated by the photoactivation of AIBN at low temperatures (0 and 40°C), is described. The kinetic diagrams for the homopolymerization of F and P were obtained following the evolution of the heat of reaction by DSC, and revealed the autoacceleration and the vitrification effects on the polymerization rate. The influence of oxygen in the photoinitiated polymerization was analyzed by determining the steady-state concentration of oxygen from the kinetic data obtained for polymerizations performed out in the presence and absence of oxygen. The results obtained indicate that P is more sensitive than F to the presence of oxygen in free radical polymerization. The photoinitiated copolymerization process is little affected by the concentration of monomers, giving similar R_p and θ_m values for both systems. However, at low polymerization temperature 0°C non-crosslinked copolymers are obtained, whereas at a temperature of 40°C, the copolymers prepared at conversion higher than 20 mol % become crosslinked as a result of the active participation of the furfuryl ring in the polymerization process at this temperature. © 1996 John Wiley & Sons, Inc.     

Photoinitiated alternating copolymerization of dialkyl maleates and fumarates with vinyl ethers

A systematic study of the free radical photoinitiated alternating crosslinking copolymerizations of dialkyl maleates and furmarates with multifunctional vinyl ethers was carried out. The photocopolymerizations were fast and highly efficient when carried out using a variety of α‐cleavage photoinitiators. The effects of the structures of the both the unsaturated esters and the vinyl ether monomers were examined. Dialkyl maleates were observed to be more reactive than the corresponding fumarate esters. The photopolymerization rates of several of these comonomer pairs were compared with standard diacrylate and dimethacrylate monomers. A range of different physical properties can be obtained by varying the length of the alkyl chain on alcohol portion of the unsaturated ester monomer. Prospects for the use of these comonomer systems in UV curable coatings, adhesives, printing inks, and composites are discussed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Homopolymerization and copolymerization of isocyanatoethyl methacrylate

This article describes the homopolymerization of isocyanatoethyl methacrylate (IEM) and its copolymerization with methyl methacrylate (MMA) in acetonitrile in the presence of 2,2′‐azobisisobutyronitrile. The constant characteristic of IEM polymerizability (k_p²/k_te = 128 × 10^?3 L mol^?1 s^?1, where k_p is the propagation constant and k_te is the termination constant) was determined. The study of IEM reactivity toward MMA gave ratios of 0.88 and 1.20 for IEM and MMA, respectively. The physicochemical properties of the IEM homopolymer and IEM/MMA copolymers were also studied. The glass‐transition temperature of poly(isocyanatoethyl methacrylate) was found to be 47 °C. From the thermogravimetric analysis of the weight‐loss percentage corresponding to the first wave of the thermogram, it was shown that the degradation mechanism of the IEM/MMA copolymers started from the isocyanate group. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4762–4768, 2006     

A study of the copolymerization of hydroxyethyl methacrylate and tetrahydrofurfuryl methacrylate

The free radical copolymerizations of hydroxyethyl methacrylate and tetrahydrofurfuryl methacrylate have been investigated at 50°C. The compositions of polymers prepared at low conversions have been determined using ¹³C-NMR, and the glass transition temperatures determined by DSC. The copolymerizations were found to be best described by a terminal model with reactivity ratios of r_H = 1.79 and r_T = 0.76. The triad fraction sequence distributions have been calculated based on the terminal model and the calculated reactivity ratios. The glass transitions have been fitted to the Gordon–Taylor equation. The best value of the Gordon–Taylor constant was found to be k_H = 1.42 ± 0.2, indicating nonideal mixing of the two monomer components in the copolymers. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3730–3737, 1999     

Radical-initiated homo- and copolymerization of cyanomethyl methacrylate

The kinetics of cyanomethyl methacrylate (CyMA) homopolymerization was investigated in acetonitrile with azobisisobutyronitrile as initiator. The rate of polymerization R_p was expressed by R_p = k[AIBN]^0.49[CyMA]^1.2 and the overall activation energy was calculated as 72.3 kJ/mol. Kinetic constants for CyMA polymerization were obtained as follows: k_p/k = 0.10 L^1/2s^?1/2; 2fk_d = 1.57 × 10^?5s^?. The relative reactivity ratios of CyMA(M₂) copolymerization with styrene (r₁ = 0.15, r₂ = 0.29) and methyl methacrylate (r₁ = 0.43, r₂ = 0.75) in acetonitrile were obtained. Applying the Q-e scheme (in styrene copolymerization) led to Q = 1.64 and e = 0.98. The glass transition temperature T_g of poly(CyMA) was observed to be 91°C by thermomechanical analysis. Thermogravimetry of poly(CyMA) showed a 10% weight loss at 265°C in air.     

Radical-Initiated homopolymerization and copolymerization of methylthiomethyl methacrylate

Methylthiomethyl methacrylate (MtMA) was synthesized and homopolymerized in solution. The poly(MtMA) is readily soluble in benzene, acetone, tetrahydrofuran, and methylene chloride at room temperature. The values of K and a in the Mark–Houwink equation, [η] = KM^a, were found to be K = 2.88 × 10^–5 and a = 0.75 when M = M_w. The glass transition temperature of poly(MtMA) was observed to be 72°C by thermomechanical analysis. Intramolecular anhydride formation occurred when poly(MtMA) was heated to 250–300°C. The kinetics of MtMA homopolymerization was investigated in benzene, using azobisisobutyronitrile as initiator. The rate of polymerization R_p was expressed by R_p = k[AIBN]^0.5[MtMA]^1.05 and the overall activation energy was calculated to be 75.7 kJ/mol. The relative reactivity ratios of MtMA in styrene copolymerizations (r₁ = 0.33, r₂ = 0.55) were obtained. Applying the Q-e scheme led to Q = 1.07 and e = 0.51 for MtMA.     

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.     

Graft copolymerization of methyl methacrylate onto curdlan

Graft copolymerization of methyl methacrylate onto curdlan was first investigated. In the graft copolymerization initiated by ammonium persulfate (APS) in DMSO under a homogeneous condition, the resulting graft copolymers had low molecular weights and low grafting percentages. However, the initiation by APS in water gave graft copolymers having relatively higher molecular weight ( ) and higher grafting percentage (548%) than those copolymers obtained by the homogeneous condition. When the graft copolymerization was carried out by cerium (IV) ammonium nitrate-HNO₃ initiation, the graft copolymer had the highest grafting percentage of 1620% without degradation of the curdlan backbone. The resulting graft copolymers were soluble in DMSO. The graft copolymers obtained by the cerium salt had narrow molecular weight distributions () compared with those by the APS catalyst in DMSO or water. The graft copolymers decomposed with sulfuric acid to isolate PMMAs, which molecular weights were larger than that of the corresponding homo-PMMAs. The structure of the grafted copolymers was characterized by IR, ¹³C NMR, DSC, and SEM. It was found that the graft copolymers exhibited the glass transition temperature (T_g), though curdlan had no T_g. As the grafting percentage increased, the T_g increased to reach 270°C, which was higher than the decomposition temperature of curdlan. The surface image of the grafted copolymers observed by SEM, showed smoothless compared with that of curdlan. It was also revealed that the graft copolymers having the grafting percentage of 1620% swelled in common organic solvents up to 4.5 times of the weight of the dry graft copolymer to form gels. © 1996 John Wiley & Sons, Inc.     

Emulsion copolymerization of styrene and methyl methacrylate

Chain transfer constants to monomer have been measured by an emulsion copolymerization technique at 44°C. The monomer transfer constant (ratio of transfer to propagation rate constants) is 1.9 × 10^?5 for styrene polymerization and 0.4 × 10^?5 for the methyl methacrylate reaction. Cross-transfer reactions are important in this system; the sum of the cross-transfer constants is 5.8 × 10^?5. Reactivity ratios measured in emulsion were r₁ (styrene) = 0.44, r₂ = 0.46. Those in bulk polymerizations were r₁ = 0.45, r₂ = 0.48. These sets of values are not significantly different. Monomer feed compcsition in the polymerizing particles is the same as in the monomer droplets in emulsion copolymerization, despite the higher water solubility of methyl methacrylate. The equilibrium monomer concentration in the particles in interval-2 emulsion polymerization was constant and independent of monomer feed composition for feeds containing 0.25–1.0 mole fraction styrene. Radical concentration is estimated to go through a minimum with increasing methyl methacrylate content in the feed. Rates of copolymerization can be calculated a priori when the concentrations of monomers in the polymer particles are known.     

Synthesis and copolymerization behavior of methacrylate dimers

Methacrylic ester-based dimers and oligomers were synthesized using a metal-based catalytic chain transfer agent. Conditions were employed which maximized the yield of unsaturated dimers, and the copolymerization behavior of these dimers was investigated. The molecular weight and polymer yield were found to decrease with increasing dimer concentration in the copolymerization feeds. © 1993 John Wiley & Sons, Inc.     

Graft copolymerization of 2-hydroxyethyl methacrylate and methyl methacrylate onto hide powder

Graft copolymerization of 2-hydroxyethyl methacrylate(HEMA) and mixtures of HEMA with methyl methacrylate (MMA) onto hide powder was attempted using ceric ammonium nitrate as initiator, with a view to optimize the conditions for graft copolymerization. Percent grafting and grafting efficiency were calculated for various variables such as monomer concentration, initator concentration and mole ratio of HEMA to MMA. R_p, R_g and R_h (rates of polymerization, grafting and homopolymerization respectively) were also evaluated. It was observed that R_p increased linearly with increasing concentration of MMA except at very low concentrations of the monomer. An explanation is given for the effect of variables on extent of grafting and grafting efficiency.     

Photo-induced graft copolymerization of methyl methacrylate on cellulose

Graft copolymerization initiated by ultraviolet light irradiation at 40°C in a hard glass vessel under nitrogen was examined. The graft copolymerization was observed to occur easily after some induction period without any use of photosensitizer, though it was found the per cent grafting and the grafting efficiency were markedly affected by the quantities of cellulose and monomer. In the system without cellulose, homopolymerization of methyl methacrylate hardly took place, but the use of cellulose caused the formation of homopolymer too, and a grafting efficiency in the range of 60–80% generally resulted. Ferric chloride or sodium anthraquinone-2,7-disulfonate (AQ) acted on the polymerization reaction as photosensitizers to reduce its induction period. Though ferric chloride acted to develop both the per cent grafting and the number of grafts, not the same effects were observed with AQ. Oxalic acid, which was employed with the object of eliminating very small amount of metals contained in cellulose, was found to act favorably in the formation of grafts, much like ferric chloride.     

Miniemulsion copolymerization of styrene–methyl methacrylate

Miniemulsion copolymerization of 50 : 50 weight fraction of styrene–methyl methacrylate monomer, using hexadecane as the cosurfactant, was carried out in both unseeded and seeded polymerizations. Effects of the hexadecane concentration and the ultrasonification time on the conversion–time curves and particle size of the final latex were investigated for unseeded polymerization. The kinetic and particle size distribution results showed that an increase in hexadecane concentration and ultrasonification time cause faster polymerization rate and smaller particle size. The mechanism of mass transport from miniemulsion droplets to polymer particles was also investigated for seeded polymerization. For this purpose a monomer miniemulsion was mixed with a fraction of a previously prepared miniemulsion latex particles prior to initiation of polymerization, using residual oil-soluble initiator in the seed latex. The concentration of hexadecane and a water-insoluble inhibitor (2,5 di-tert-butyl hydroquinone) in the miniemulsions were the main variables. Seeded polymerizations were also carried out in the presence of miniemulsion droplets containing a water-insoluble inhibitor and water-soluble initiator. The inhibitor concentration and the agitation speed during the course of polymerization were the experimental variables. The kinetic and particle size results from these seeded experiments suggested that collision between miniemulsion droplets and polymer particles may play a major role in the transport of highly water-insoluble compounds.     

Graft copolymerization onto jute fiber: Ceric ion-initiated graft copolymerization of methyl methacrylate

Graft copolymerization of methyl methacrylate (MMA) was carried out on both defatted and bleached jute fibers using ceric ammonium sulfate (CAS) as the initiator. In order to obtain the optimum condition for grafting, the effects of initiator concentrations, temperature, time of reaction, lignin content of jute, and the monomer concentration were studied. The maximum percent grafting and grafting efficiency were found to be 132% and 0.71, respectively. Kinetic studies showed that at 0.03M CAS, the reaction appeared to obey the second-order process. The activation energies were found to be 7.74 and 5.12 kcal/mole for defatted (lignin content, 15.7%) and chlorite-bleached jute (lignin content 10%), respectively. The activation energies of graft copolymerization of MMA onto jute fiber are compared with the energies of activation of graft copolymerization of acrylonitrile (AN).     

Dispersion copolymerization of methyl methacrylate and n-butyl acrylate

In the dispersion copolymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA), the particle size increases with an increasing MMA fraction in the comonomer. The power dependence of the particle size on the initiator concentration also increases with an increasing MMA concentration. Similar to what can be found in the homopolymerizations, two populations can be observed in the molecular weight distributions of the copolymers. Core–shell structured particles with a poly(methyl methacrylate)-rich core and a poly(n-butyl acrylate)-rich shell result from the copolymerizations because of the significantly different reactivity ratios. The reaction rates of the dispersion copolymerization are lower than those of the homopolymerization of BA and close to or lower than those of the homopolymerization of MMA, depending on the ratio of the monomers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2105–2112, 2007     

Radical copolymerization of 2-acryloyl thioxanthone with methyl methacrylate

A novel monomer, 2-acryloyl thioxanthone (TXA), was prepared by reaction of 2-hydroxy thioxanthone with acryloyl chloride. Copolymerization of TXA with methyl methacrylate (MMA) in DMF at 80°C was studied in order to evaluate relative reactivities of these monomers. Values of 1.36 and 0.5 were found for the respective reactivity ratios of MMA and TXA, respectively. The resonance stabilization and polar properties were determined and discussed in terms of spectroscopic data.     

Semicontinuous emulsion copolymerization of methyl methacrylate and ethyl acrylate

The monomer addition policies required to produce homogeneous methyl methacrylateethyl acrylate copolymers of different compositions were determined by means of a semiempirical approach. This approach is useful for systems about which only a limited information is available. Applying this method only three reactions were needed to obtain homogeneous copolymers in a minimum process time. Comparisons were made between the results obtained using this monomer addition strategy and those from copolymerizations carried out under the classical starved conditions.