Synthesis of well‐defined polystyrene‐graft‐poly(methyl methacrylate)

A well‐defined graft copolymer, polystyrene‐graft‐poly(methyl methacrylate), was synthesized in two steps. In the first step, styrene and p‐vinyl benzene sulfonyl chloride were copolymerized via reversible addition–fragmentation chain transfer polymerization (RAFT) in benzene at 60 °C with 2‐(ethoxycarbonyl)prop‐2‐yl dithiobenzoate as a chain transfer agent and 2,2′‐azobis(isobutyronitrile) as an initiator. In the second step, poly[styrene‐co‐p‐(vinyl benzene sulfonyl chloride)] was used as a macroinitiator for the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in toluene at 80 °C with CuCl as a catalyst and 2,2′‐bipyridine as a ligand. With sulfonyl chloride groups as the initiating sites for the ATRP of MMA, high initiation efficiencies were obtained. Copyright © 2006 Society of Chemical Industry     

A kinetic study on polymerization of methyl methacrylate with di‐t‐butyl perfumarate

Di‐t‐butyl perfumarate (DBPF) was found to induce the radical polymerizations of various vinyl monomers at 60°C in benzene, although the initiation activity was considerably lower than those of dimethyl 2,2′‐azobisisobutyrate and benzoyl peroxide. The polymerizations with DBPF showed a tendency of dead‐end polymerization. The polymerization of methyl methacrylate (MMA) with DBPF was kinetically studied in chlorobenzene. The initial polymerization rate (R_p) was given by R_p = k [DBPF]^0.5 [MMA]^1.1. The overall activation energy of the polymerization was 47 kJ/mol, a very low value. Use of this value and activation energies of propagation and termination for MMA gave an unexpectedly low activation energy (65 kJ/mol) to the decomposition of DBPF, a t‐butyl perester, in the polymerization system. An ESR study on the polymerization of di‐2‐ethylhexyl itaconate with DBPF revealed that the observed dead‐end tendency comes from the consumption of DBPF. These results suggest that the initiator efficiency of DBPF is considerably low in the present polymerization systems. Some solvent effect was observed on the polymerization of MMA with DBPF. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 218–224, 2000     

Gas‐Phase Assisted Surface Polymerization Behavior of β‐Propiolactone on Inorganic and Organic Substrates and Consequent Composite Production

Summary: Gas‐phase assisted surface polymerization (GASP) of β‐propiolactone (βPL) was investigated using substrate‐supported anionic initiators to produce a strongly bonded poly(β‐propiolactone) (PPL)/CaO composite and a novel PPL crystalline deposit with a high melting point value on Al plates. The polymerization of βPL smoothly proceeded in the gas phase to give high‐molecular‐weight PPLs having high PDI values. An almost linear relationship between value and incremental increase in the deposit suggested the living nature of the GASP of βPL. The obtained polymer‐coated substrates, especially PPL/CaO composite, showed strong interaction at the organic/inorganic interface. Moreover, the thermal and structural analyses of deposits revealed that some specific conformations were formed on CaO powder and Al plate surfaces to give highly crystallized deposits. These results demonstrate that the GASP is an effective method for coating any substrate that has a complex shape and a surface morphology.

Accumulation process of poly(β‐propiolactone) on CaO as substrate‐supported initiator during GASP.     

Polymerization of methyl methacrylate with a thermal iniferter: Diethyl 2,3‐dicyano‐2,3‐di(p‐tolyl)succinate

A hexa‐substituted ethane type compound, diethyl‐2,3‐dicyano‐2,3‐di(p‐tolyl)succinate (DCDTS), was successfully synthesized and used for initiation of methyl methacrylate (MMA) polymerization. The reaction demonstrated the characteristics of a “living” polymerization; i.e., both the yield and the molecular weight of the resulting polymers increased linearly with increasing reaction time, the molecular‐weight distribution of PMMA obtained was ～1.60 and almost unaffected by the conversion, and the resultant polymer can be chain extended by adding fresh MMA. End group analysis of the resultant PMMA confirmed that DCDTS behaves as a thermal iniferter for MMA polymerization. A block copolymer was prepared from the resultant PMMA, which contains a hexa‐substituted C? C bond functional end group. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2566–2572, 2001     

Kinetics of atom transfer radical polymerization of crosslinkable terpolymer P(MMA‐BA‐HEMA)

A crosslinkable terpolymer P(MMA‐BA‐HEMA) was prepared by atom transfer radical copolymerization of 2‐hydroxyethyl methacrylate, methyl methacrylate and butyl acrylate. The structure of the terpolymer was characterized by ¹H NMR and gel permeation chromatography. The effects on the polymerization of ligand, initiator, solvent, CuCl₂ added in the initial stage and reaction temperature were investigated. The optimal reaction conditions were ethyl 2‐bromopropionate as initiator, CuCl/PMDETA as catalyst, cyclohexanone as solvent, catalyst/ligand = 1:1.5, [M]₀:[I]₀ = 200:1 and temperature 70 °C. The reaction followed first‐order kinetics with respect to monomer concentration, indicating the best control over the polymerization process, a constant concentration of the propagating radical during the polymerization, efficient control over M_n of the polymer and low polydispersity (M_w/M_n < 1.3). © 2013 Society of Chemical Industry     

Photo‐Induced atom transfer radical polymerization with nanosized α‐Fe2O3 as photoinitiator

Photo‐induced atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was achieved in poly(ethylene glycol)‐400 with nanosized α‐Fe₂O₃ as photoinitiator. Well‐defined poly(methyl methacrylate) (PMMA) was synthesized in conjunction with ethyl 2‐bromoisobutyrate (EBiB) as ATRP initiator and FeCl₃·6H₂O/Triphenylphosphine (PPh₃) as complex catalyst. The photo‐induced polymerization of MMA proceeded in a controlled/living fashion. The polymerization followed first‐order kinetics. The obtained PMMA had moderately controlled number‐average molecular weights in accordance with the theoretical number‐average molecular weights, as well as narrow molecular weight distributions (M_w/M_n). In addition, the polymerization could be well controlled by periodic light‐on–off processes. The resulting PMMA was characterized by ¹H nuclear magnetic resonance and gel permeation chromatography. The brominated PMMA was used further as macroinitiator in the chain‐extension with MMA to verify the living nature of photo‐induced ATRP of MMA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42389.     

Preparation of monodispersed and lipophilic attapulgite and polystyrene nanorods via surface‐initiated atom transfer radical polymerization

A new kind of initiator, 3‐(2‐bromo‐2‐methylacryloxy)propyltriethysiliane (MPTS‐Br), was prepared with a simply hydrobrominated commercial silane coupling agent (3‐methacryloxy‐proplytriethysilane, MPTS). It has been one‐step self‐assemble onto the surface of attapulgite (ATP) nanorods in the dispersion system, and by using this initiator‐modified nanorod (MPTS‐Br‐modified ATP nanoparticles, ATP‐MPTS‐Br) as macroinitiator for atom transfer radical polymerization (ATRP). Structurally well‐defined homopolymer polystyrene (PS) and block polymer poly(styrene‐b‐methyl methacrylate) (PS‐b‐PMMA) chains were then grown from the needle‐shaped nanorods surface to yield monodispersed nanorods composed of ATP core and thick‐coated polymer shell (ATP and PS). The graft polymerization parameters exhibited the characteristics of a controlled/”living” polymerization. The PS‐grafted ATP nanorods could be dispersed well in organic solvent with nanoscale. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of well‐defined comb‐like amphiphilic copolymers with protonizable units in the pendent chains: 1. Preparation of narrow polydispersity copolymers of methyl methacrylate and 2‐hydroxyethyl methacrylate by atom‐transfer radical polymerization

Well‐defined methyl methacrylate (MMA) and 2‐(trimethylsiloxy)ethyl methacrylate (Pro‐HEMA) copolymers were prepared by atom‐transfer radical polymerization(ATRP), using CuCl/2,2′‐bipyridine as catalytic system and p‐toluenesulfonyl chloride as initiator. ATRP process of MMA and Pro‐HEMA was monitored by ¹H NMR, and the kinetic curves of the MMA/Pro‐HEMA copolymerization were plotted in terms of the ¹H NMR data. At low content of Pro‐HEMA in the feed composition, the copolymerization can be well controlled with the molecular weight, polydispersity and the monomer distribution in the copolymer chain. With the increase of Pro‐HEMA content in the feed mixture, the composition of the final copolymer deviates from the composition of the feed mixture gradually, and gradient copolymers of MMA/Pro‐HEMA can be obtained. Through the hydrolysis process, well‐defined copolymers of MMA/HEMA were obtained from poly(MMA/Pro‐HEMA). Copyright © 2003 Society of Chemical Industry     

Surface‐initiated atom‐transfer radical polymerization (SI‐ATRP) of methyl methacrylate from carbon fibre

Surface modification of carbon fibre (CF) by well‐defined polymer brushes was carried out using the ‘grafting from’ method. Poly(methyl methacrylate)‐grafted carbon fibre (CF‐PMMA) was successfully prepared by surface‐initiated atom‐transfer radical polymerization (SI‐ATRP) of methyl methacrylate (MMA) from the macro‐initiator, bromo‐acetic ester‐modified carbon fibre (CF‐BrA), with the complex of 1,10‐phenanthroline and Cu(I)Br as catalyst. The percentage of grafting (PG%) and the conversion of monomer (C%) increased linearly with increasing of polymerization time, and reached 24.0 % and 6.7 %, respectively, after a polymerization time of 6 h, calculated from the elemental analyses (EA). The structural and surface morphological analyses were conducted with Fourier‐transform infrared (FTIR) spectroscopy, X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Copyright © 2005 Society of Chemical Industry     

Radical polymerization of vinyl monomers in the presence of carbon black initiated by 2,2'‐azobisisobutyronitrile and benzoyl peroxide in ionic liquid

The radical polymerization behavior of vinyl monomers, such as styrene, methyl methacrylate (MMA), and vinyl acetate (VAc), in the presence of carbon black initiated by benzoyl peroxide (BPO) and 2,2'‐azobisisobutyronitrile (AIBN) in ionic liquid (IL) was compared with those in toluene. 1‐Butyl‐3‐methylimidazolium hexafluorophosphate was used as IL. The radical polymerization of vinyl monomers initiated by BPO and AIBN in the presence of carbon black was remarkably retarded in toluene. On the contrary, the retardation of the polymerization by carbon black was considerably reduced in IL. During the radical polymerization in the presence of carbon black, a part of polymer formed was grafted onto carbon black surface based on the termination reaction of the growing polymer radicals with carbon black surface. The percentage of grafting and molecular weight of polymer in IL were much higher than those in toluene. This may be due to the fact that lifetime of the growing polymer radical is prolonged because of high viscosity of IL. Therefore, the growing polymer radicals with higher molecular weight were trapped by carbon black surface, because of stabilization of polymer radicals. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Fe‐mediated ARGET atom transfer radical polymerization of methyl methacrylate in ionic liquid‐based microemulsion

Poly(methyl methacrylate) (PMMA) was synthesized by activator regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) of MMA in ionic liquid‐based microemulsion with polyoxyethylene sorbitan monooleate (Tween 80) as surfactant. The polymerization was carried out at 25°C with CCl₄ as initiator, FeCl₃·6H₂O/N,N,N′,N′‐tetramethyl‐1,2‐ethanediamine (TMEDA) as catalyst complex in the presence of reducing agent ascorbic acid (VC). The polymerization kinetics showed the feature of controlled/″living″ process as evidenced by a linear first‐order plot. The well‐controlled polymers were obtained with narrow polydispersity indices and the ionic liquid‐based microemulsions were transparent with a particle size less than 30 nm. The obtained polymer was characterized by ¹H NMR and gel permeation chromatography. The chain extension was successfully achieved by the obtained PMMA macroinitiator/FeCl₃·6H₂O/TMEDA/VC initiator system based on ARGET ATRP method. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Kinetics of azo‐initiated 1‐vinyl‐2‐pyrrolidone polymerizations at low conversions in aqueous media

The free‐radical polymerization behavior of 1‐vinyl,2‐pyrrolidone (NVP) was studied at low conversions, using capillary dilatometry. The aqueous media were kept at neutral pH and the studies were conducted isothermally, at 40 or 45°C. The azo‐type initiators used were 4,4′‐azobis‐4‐cyanopentanoic acid (ACPA), 2,2′‐azobisisobutyronitrile (AZBN), and 2,2′‐azobis[2‐(2‐imidazolin‐2‐yl)propane dihydrochloride] (ABDH). The monomer concentration and initiator concentration ranges were 1.17–2.34 mol L⁻¹ and 1–8 mmol L⁻¹, respectively. The rates of polymerization (R_p) and orders of reaction with respect to NVP and the initiator were evaluated and the kinetic equations were found to be R_p ∝ [NVP] [ACPA]^1.2; R_p ∝ [NVP] [AZBN]^1.1; and R_p ∝ [NVP]^2.2 [ABDH]^1.1. The polymers obtained were characterized by their viscosity numbers and correlation of the viscosity average molecular weights made with the type and amount of the azo initiator. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 239–246, 2000     

2‐Mercapto thioxanthone as a chain transfer agent in free‐radical polymerization: A versatile route to incorporate thioxanthone moieties into polymer chain‐ends

2‐Mercapto thioxanthone (TX‐SH) was used as a chain transfer agent in free‐radical polymerization of methyl methacrylate (MMA) and styrene (St), by using 2,2′‐azobisisobutyronitrile (AIBN) as an initiator at 70°C. Chain transfer constants were found to be 1.41 and 0.12 for St and MMA, respectively. The use of TX‐SH as a chain transfer agent leads to the formation of polymers with thioxanthone (TX) end groups. The incorporation TX moiety was confirmed by spectral measurements. Polymers obtained this way were used as triplet photosensitizer in free‐radical polymerization of MMA in the presence of a hydrogen donor such as N‐methyldiethanolamine (MDEA). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3766–3770, 2007     

Kinetic investigations of acrylic–polyurethane composite latex

The effect of various reaction parameters on the rate of polymerization, R_p, and on the particle size and morphology of aqueous acrylic–polyurethane hybrid dispersions, prepared by semibatch emulsion polymerization, was investigated. The particles of polyurethane dispersion were used as seeds during the polymerization of acrylic component: methyl methacrylate (MMA), butyl acrylate (BA), and a mixture of MMA and BA with the ratio of 1:1. These emulsions were found to form structured polymer particles in aqueous media using scanning electron microscopy. The kinetics of the emulsion polymerization was studied on the basis of Wessling's model. The influence of emulsifier and initiator concentrations, including the monomer feed rates, R_m, on the rates of polymerization and on the properties of the resulting dispersions were studied. The number of particles and the particle size were also measured during the polymerization process. The final values were found to be independent of the concentration of the emulsifier, initiator and the monomer feed rate in monomer starved conditions. In the steady‐state conditions, during the seeded semibatch hybrid emulsion polymerization, the rate of polymerization and the monomer feed rate followed the Wessling relationship 1/R_p = 1/K + 1/R_m. The dispersions MMA/PU, BA/PU, and MMA/BA/PU have K values of 0.0441, 0.0419 and 0.0436 mol/min, respectively. The seeded BA/PU hybrid polymerization proceeded according to Smith‐Ewart Case I kinetics, while the MMA/PU hybrid emulsions demonstrate Case II of the Smith‐Ewart kinetic model. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2639–2649, 2002     

Polymerization of 1,3‐dienes containing functional groups: 8. Free‐radical polymerization of 2‐triethoxysilyl‐ 1,3‐butadiene

The presence of a bulky substituent at the 2‐position of 1,3‐butadiene derivatives is known to affect the polymerization behavior and microstructure of the resulting polymers. Free‐radical polymerization of 2‐triethoxysilyl‐1,3‐butadiene ( 1 ) was carried out under various conditions, and its polymerization behavior was compared with that of 2‐triethoxymethyl‐ and other silyl‐substituted butadienes. A sticky polymer of high 1,4‐structure ( ) was obtained in moderate yield by 2,2′‐azobisisobutyronitrile (AIBN)‐initiated polymerization. A smaller amount of Diels–Alder dimer was formed compared with the case of other silyl‐substituted butadienes. The rate of polymerization (R_p) was found to be R_p = k[AIBN]^0.5[ 1 ]^1.2, and the overall activation energy for polymerization was determined to be 117 kJ mol^?1. The monomer reactivity ratios in copolymerization with styrene were r ₁ = 2.65 and r_st = 0.26. The glass transition temperature of the polymer of 1 was found to be ?78 °C. Free‐radical polymerization of 1 proceeded smoothly to give the corresponding 1,4‐polydiene. The 1,4‐E content of the polymer was less compared with that of poly(2‐triethoxymethyl‐1,3‐butadiene) and poly(2‐triisopropoxysilyl‐1,3‐butadiene) prepared under similar conditions. Copyright © 2010 Society of Chemical Industry     

Novel comb‐structured‐polymer‐grafted carbon black by surface‐initiated atom transfer radical polymerization and ring‐opening polymerization

Novel comb‐structured‐polymer‐grafted carbon black (CB) was synthesized with a combination of surface‐initiated atom transfer radical polymerization and ring‐opening polymerization. First, poly(2‐hydroxyethyl methacrylate) (PHEMA) was grafted onto the CB surface by surface‐initiated atom transfer radical polymerization. The prepared CB‐g‐PHEMA contained 35.6–71.8% PHEMA, with the percentage depending on the molar ratio of the reagents and the reaction temperature. Then, with PHEMA in CB‐g‐PHEMA as the macroinitiator, poly(?‐caprolactone) (PCL) was grown from the CB‐g‐PHEMA surface by ring‐opening polymerization in the presence of stannous octoate. CB‐g‐PHEMA and CB‐g‐(PHEMA‐g‐PCL) were characterized with Fourier transform infrared, ¹H‐NMR, thermogravimetric analysis, dynamic light scattering, and transmission electron microscopy. The resultant grafted CB had a shell of PHEMA‐g‐PCL. On the whole, the CB nanoparticles were oriented in dendritic lamellae formed by these shells. This hopefully will result in applications in gas sensor materials and nanoparticle patterns. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of well‐defined comblike hydroxy‐functionalized atactic polystyrene promoted by metallocene/tin/poly(phenyl glycidyl ether)‐co‐formaldehyde

Well‐defined comblike atactic polystyrene functionalized with hydroxyl groups was synthesized via living/controlling radical polymerization promoted by metallocene complexes in the presence of poly(phenyl glycidyl ether)‐co‐formaldehyde as the initiator and Sn as a reducing agent. The effect of the polymerization conditions, such as the ratio of initiator to monomer, temperature, and polymerization time, and the structure of the metallocene complex on the polymerization process were investigated. The resulting polymers were characterized by gel permeation chromatography, multiangle laser light scattering, ¹H‐NMR, and ¹³C‐NMR. The results show that the polymer had a narrow molecular weight distribution in the range 1.1–1.4 and the number‐average molecular weight of the polymer linearly depended on the monomer conversion within the polymerization timescale, which confirmed that living radical polymerization characteristics prevailed in the polymerization process. Both the number of arms and the number of hydroxyl groups in each polymer molecule were about four, which suggested that they arose from the epoxy functional groups of the initiator. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

High‐molecular‐weight polyacrylonitrile by atom transfer radical polymerization

A single‐pot atom transfer radical polymerization was used for the first time to successfully synthesize polyacrylonitrile with a molecular weight higher than 80,000 and a narrow polydispersity as low as 1.18. This was achieved with CuBr/isophthalic acid as the catalyst, 2‐bromopropionitrile as the initiator, and N,N‐dimethylformamide as the solvent. The effects of the solvent on the polymerization of acrylonitrile were also investigated. The induction period was shorter in N,N‐dimethylformamide than in propylene carbonate and toluene, and the rate of the polymerization in N,N‐dimethylformamide was fastest. The molecular weight of polyacrylonitrile agreed reasonably well with the theoretical molecular weight in N,N‐dimethylformamide. When chlorine was used in either the initiator or the catalyst, the rate of polymerization showed a trend of decreasing, and the molecular weight deviated from the theoretical predication significantly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3372–3376, 2006     

Radical thermo‐ and sonopolymerization of methyl methacrylate initiated by iodobenzene 1,1‐diacetate

The efficiency of iodobenzene 1,1‐diacetate or (diacetoxyiodo)benzene (DAIB) as a thermo‐ and sono‐initiator of methyl methacrylate (MMA) in radical bulk polymerization is tested. The polymerization kinetics and molecular‐mass characteristics support an assumption for a combined polymerization mechanism including a classical bimolecular termination with chain transfer reaction and iniferter quasi‐living polymerization. In addition to the equilibrium formation and degradation of the ‘dormant’ polymer ends, other possible decomposition reactions of the hypervalent iodine bond are the probable reason for the deviation of this polymerization from the iniferter polymerization mechanism. These reactions bear some similarity to the two‐step addition–fragmentation chain transfer mechanism of controlled radical polymerization. The application of the poly(MMA) obtained as a macroinitiator is evidence of ‘dormant’ chain end formation. © 2001 Society of Chemical Industry     

Morphological and Physical Properties of Triblock Copolymers of Methyl Methacrylate and 2‐Ethylhexyl Methacrylate

Summary: Triblock copolymers of methyl methacrylate (MMA) and 2‐ethylhexyl methacrylate (EHMA) [that is, poly(MMA–EHMA–MMA)] were prepared by an emulsion atom‐transfer radical polymerization. The relationships of their structural, morphological, and physical properties were investigated. The latex particles had core‐shell morphologies and the block copolymers experienced phase separation. Small latex particles with a low number of cores could deform and wet silicon‐wafer surfaces, but the deformation of large latex particles was restricted by the internal two‐phase morphology of the particles. Latex casting produced continuous pinhole‐free films, in which hard poly(MMA) (PMMA) cores of different latex particles merged and provided interparticle connections. The morphology of solution‐cast films depended on block composition, solvent type, and film thickness. For all the prepared polymer samples, thick films cast in toluene had poly(EHMA) (PEHMA) materials at air surface, whereas those cast in tetrahydrofuran had a sponge‐like PMMA surface structure. Thin toluene‐cast films from P(MMA–EHMA–MMA) with the block degrees of polymerization ( ) 200–930–200 showed spherical PMMA domains and those from 380–930–380 yielded a protruded worm‐like PMMA structure. The copolymer materials were coated on a glass surface for peeling tests. The films gave good hot‐melt adhesion properties when the of the PEHMA block was over 600. The peeling strength depended on the lengths of both PEHMA and PMMA blocks. The P(MMA–EHMA–MMA) sample with of 310–930–310 yielded the highest peeling strength of 7.4 kgf · inch^?1. The developed material is demonstrated to be a good candidate for a solvent‐free, hot‐melt, pressure‐sensitive adhesives for special‐purpose applications such as medical tapes and labels.