Copolymerization and thermal behavior of methyl methacrylate with N‐(phenyl/p‐tolyl) itaconimides

This study describes the synthesis, characterization, and thermal behavior of copolymers of methyl methacrylate (MMA) and N‐p‐tolyl itaconimide (PTI)/N‐phenyl itaconimide (I). Homopolymerization and copolymerization of N‐(phenyl/p‐tolyl) itaconimide with MMA was carried out by use of various mole fractions of N‐aryl itaconimide in the initial feed from 0.1 to 0.5, using azobisisobutyronitrile as an initiator and tetrahydrofuran as the solvent. The copolymer composition was determined by ¹H‐NMR spectroscopy using the proton resonance signals attributed to –OCH₃ of MMA (δ = 3.5–3.8 ppm) and the aromatic protons (δ = 7.0–7.5 ppm) of N‐aryl itaconimide. The reactivity ratios of the monomers were found to be r₁ (PTI) = 1.33 ± 0.05/r₂ (MMA) = 0.24 ± 0.03 and r₁ (I) = 1.465 ± 0.035/r₂ (MMA) = 0.385 ± 0.005. The molecular weight of the copolymers decreased with increasing mole fraction of N‐aryl itaconimide in the copolymers. Glass‐transition temperature (T_g) and thermal stability of PMMA increased with increasing amounts of itaconimides in the polymer backbone. A significant increase in the percentage char yield at 700°C was observed on incorporation of a low mole fraction of N‐aryl itaconimides. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1195–1202, 2003     

Synthesis of methyl methacrylate and N‐aryl itaconimide block copolymers via atom‐transfer radical polymerization

The paper describes the synthesis of block copolymers of methyl methacrylate (MMA) and N‐aryl itaconimides using atom‐transfer radical polymerization (ATRP) via a poly(methyl methacrylate)–Cl/CuBr/bipyridine initiating system or a reverse ATRP AIBN/FeCl₃·6H₂O/PPh₃ initiating system. Poly(methyl methacrylate) (PMMA) macroinitiator, ie with a chlorine chain‐end (PMMA‐Cl), having a predetermined molecular weight (M_n = 1.27 × 10⁴ g mol^?1) and narrow polydispersity index (PDI = 1.29) was prepared using AIBN/FeCl₃·6H₂O/PPh₃, which was then used to polymerize N‐aryl itaconimides. Increase in molecular weight with little effect on polydispersity was observed on polymerization of N‐aryl itaconimides using the PMMA‐Cl/CuBr/Bpy initiating system. Only oligomeric blocks of N‐aryl itaconimides could be incorporated in the PMMA backbone. High molecular weight copolymer with a narrow PDI (1.43) could be prepared using tosyl chloride (TsCl) as an initiator and CuBr/bipyridine as catalyst when a mixture of MMA and N‐(p‐chlorophenyl) itaconimide in the molar ratio of 0.83:0.17 was used. Thermal characterization was performed using differential scanning calorimetry (DSC) and dynamic thermogravimetry. DSC traces of the block copolymers showed two shifts in base‐line in some of the block copolymers; the first transition corresponds to the glass transition temperature of PMMA and second transition corresponds to the glass transition temperature of poly(N‐aryl itaconimides). A copolymer obtained by taking a mixture of monomers ie MMA:N‐(p‐chlorophenyl) itaconimide in the molar ratio of 0.83:0.17 showed a single glass transition temperature. Copyright © 2005 Society of Chemical Industry     

Copolymerization of N‐aryl substituted itaconimide with methyl methacrylate: Effect of substituents on monomer reactivity ratio and thermal behavior

The article describes the synthesis and characterization of N‐(4‐methoxy‐3‐chlorophenyl) itaconimide (MCPI) and N‐(2‐methoxy‐5‐chlorophenyl) itaconimide (OMCPI) obtained by reacting itaconic anhydride with 4‐methoxy‐3‐chloroanisidine and 2‐methoxy‐5‐chloroanisidine, respectively. Structural and thermal characterization of MCPI and OMCPI monomers was done by using ¹H NMR, FTIR, and differential scanning calorimetry (DSC). Copolymerization of MCPI or OMCPI with methyl methacrylate (MMA) in solution was carried out at 60°C using AIBN as an initiator and THF as solvent. Feed compositions having varying mole fractions of MCPI and OMCPI ranging from 0.1 to 0.5 were taken to prepare copolymers. Copolymerizations were terminated at low percentage conversion. Structural characterization of copolymers was done by FTIR, ¹H NMR, and elemental analysis and percent nitrogen content was used to calculate the copolymer composition. The monomer reactivity ratios for MMA–MCPI copolymers were found to be r₁ (MMA) = 0.32 ± 0.03 and r₂ (MCPI) = 1.54 ± 0.05 and that for MMA–OMCPI copolymers were r₁ (MMA) = 0.15 ± 0.02 and r₂ (OMCPI) = 1.23 ± 0.18. The intrinsic viscosity [η] of the copolymers decreased with increasing mole fraction of MCPI/or OMCPI. The glass transition temperature as determined from DSC scans was found to increase with increasing amounts of OMPCI in copolymers. A significant improvement in the char yield as determined by thermogravimetry was observed upon copolymerization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2391–2398, 2006     

Thermal and mechanical properties of copolymers of methyl methacrylate with N‐aryl itaconimides

The article describes the preparation of cast copolymer sheets of methyl methacrylate with varying mole fractions of N‐(p‐methoxyphenyl) itaconimide/N‐(2‐methoxy‐5‐chlorophenyl) itaconimide/N‐(3‐methoxy‐5‐chlorophenyl) itaconimide monomers by bulk copolymerization using azobisisobutyronitrile as an initiator. The effect of incorporation of varying mole fractions of N‐arylsubstituted itaconimides in poly(methyl methacrylate) (PMMA) backbone on the thermal, optical and physicomechanical properties of cast acrylic sheets were evaluated. The glass transition temperature and the thermal stability increased with increasing amounts of itaconimides in the polymer backbone. An increase in tensile strength, flexural strength, and storage modulus was also observed. The impact strength decreased marginally upon incorporation of imides into the polymer backbone. A slight decrease in the transparency and a significant increase (4–50%) in the haze was observed. The chemical resistance of PMMA remains unaffected by copolymerization. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Copolymerization of N‐(4‐carboxyphenyl) itaconimide or N‐(4‐carboxyphenyl) itaconamic acid with methyl methacrylate

This paper describes the synthesis and characterization of N‐(4‐carboxyphenyl) itaconamic acid (CPA) and N‐(4‐carboxyphenyl) itaconimide (CPI) obtained by reacting itaconic anhydride with p‐aminobenzoic acid. Structural and thermal characterization of CPA and CPI was done using ¹H‐NMR, FTIR, and differential scanning calorimetry (DSC). Copolymerization of CPA or CPI with methyl methacrylate (MMA) in solution was carried out at 60 °C using azobisisobutyronitrile as an initiator and dimethyl acetamide or THF as solvent. Feed compositions having varying mole fractions of CPA or CPI ranging from 0.05–0.20 or 0.1–0.5 were taken to prepare copolymers. Copolymerizations were terminated at low percentage conversion. Structural characterization of copolymers was done by ¹H‐NMR and elemental analysis. Copolymer composition was determined using percentage nitrogen content. The reactivity ratios were r₁ (MMA) = 0.68 ± 0.06 and r₂ (CPI) = 0.46 ± 0.06. The intrinsic viscosity [η] was determined using an Ubbelohde suspension level viscometer. [η] decreased with increasing mole fraction of N‐(p‐carboxyphenyl) itaconimide or N‐(p‐carboxyphenyl) itaconamic acid in copolymers. Glass transition temperature and thermal stability of the copolymers were determined using DSC and thermogravimetric analysis, respectively. The glass transition temperature (T_g) as determined from DSC scans increased with increasing amounts of CPA or CPI in copolymers. A significant improvement in the char yield was observed upon copolymerization. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1909–1915, 2005     

Copolymerization of methyl methacrylate with N-(methoxyphenyl) itaconimides

This article describes the synthesis and characterization of N-(3-methoxyphenyl) itaconimide (MAI) and N-(4-methoxyphenyl) itaconimide (PAI) obtained by the reaction of itaconic anhydride with m-anisidine and p-anisidine, respectively. Structural and thermal characterization of MAI and PAI monomers was performed with Fourier transform infrared (FTIR), ¹H-NMR, differential scanning calorimetry (DSC), and thermogravimetric analysis. Copolymerization of methyl methacrylate (MMA) with various amounts of MAI or PAI ranging from 0.1 to 0.5 was performed in solution with azobisisobutyronitrile as an initiator. Structural and molecular characterization of copolymers was performed with FTIR, ¹H-NMR, elemental analysis, and gel permeation chromatography. The nitrogen percentage was used to calculate the copolymer composition. The monomer reactivity ratios for MMA–MAI copolymers were found to be 1.00 ± 0.01 for MMA and 0.99 ± 0.07 for MAI; those for MMA–PAI copolymers were 0.93 ± 0.02 for MMA and 1.11 ± 0.10 for PAI. The molecular weights of the copolymers were in the range of 0.94–9.7 × 10³ (number-average molecular weight) and 3.3–101.8 × 10³ (weight-average molecular weight), with polydispersity indices in the range of 1.5–4.1. The molecular weight decreased with the increasing molar fraction of imide in the polymer backbone. The glass-transition temperature, as determined from DSC scans, increased with increasing amounts of itaconimides in the copolymers. A significant improvement in the char yield, as determined by thermogravimetry, was observed upon copolymerization. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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,characterizations and thermal behavior of methyl methacrylate and N‐(p‐carboxyphenyl) methacrylamide/acrylamide copolymers

The synthesis, characterization, and thermal properties of copolymers of methyl methacrylate (MMA) and N‐(p‐carboxyphenyl) methacrylamide/acrylamide (CPMA/CPA) are described. The copolymerization was carried out in solution by taking different mole fractions (0.1–0.5) of CPMA/CPA in the initial feed using azobisisobutyronitrile as an initiator and dimethylformamide as a solvent at 60°C. The copolymer composition was determined from ¹H‐NMR spectra by taking the ratio of the proton resonance signal due to the  OCH₃ of MMA (δ = 3.59 ppm) and the aromatic protons (δ = 7.6–7.8 ppm) of CPMA/CPA. The monomer reactivity ratios of MMA:CPMA and MMA:CPA were determined using the Fineman Ross and Kelen Tudos methods and were found to be 1.32 ± 0.01 [MMA], 1.11 ± 0.02 [CPMA], 2.60 ± 0.01 [MMA], and 0.20 ± 0.01 [CPA]. Incorporation of these comonomers in the MMA backbone resulted in an improvement in the glass‐transition temperature and thermal stability. The percent char also increased with the increase of CPMA/CPA content in the copolymers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 259–267, 2000     

Studies on the copolymerization of methyl methacrylate and N-aryl maleimides

This article describes the synthesis and characterization of copolymers of methyl methacrylate (MMA) and N-4-chlorophenyl maleimide (PC)/N-3-chlorophenyl maleimide (MC). The copolymers were synthesized by varying the mole fraction of N-aryl maleimides from 0.1 to 0.5 in the initial feed using azobisisobutyronitrile (AIBN) as an initiator and tetrahydrofuran (THF) as the solvent. The copolymer composition was determined from the ¹H-NMR spectra by taking the ratio of proton resonance signals due to methoxy protons (δ = 3.59 ppm) of MMA and aromatic protons (δ = 7.2–7.4 ppm) of N-aryl maleimides. The reactivity ratios for MMA–PC and MMA–MC copolymers were found to be 0.952 (r₁), 0.029 (r₂) and 0.833 (r₁) and 0.033 (r₂), respectively. Thermal characterization of the copolymers was done using differential scanning calorimetry (DSC) and dynamic thermo-gravimetry. Initial decomposition temperature and glass transition temperature increased with increasing mole fraction of N-aryl maleimide content in the copolymers. © 1996 John Wiley & Sons, Inc.     

Synthesis and characterization of diblock,triblock, and multiblock copolymers containing poly(3‐hydroxy butyrate) units

A poly[(R,S)‐3‐hydroxybutyrate] macroinitiator (PHB‐MI) was obtained through the condensation reaction of poly[(R,S)‐3‐hydroxybutyrate] (PHB) oligomers containing dihydroxyl end functionalities with 4,4′‐azobis(4‐cyanopentanoyl chloride). The PHB‐MI obtained in this way had hydroxyl groups at two end of the polymer chain and an internal azo group. The synthesis of ABA‐type PHB‐b‐PMMA block copolymers [where A is poly(methyl methacrylate) (PMMA) and B is PHB] via PHB‐MI was accomplished in two steps. First, multiblock active copolymers with azo groups (PMMA‐PHB‐MI) were prepared through the redox free‐radical polymerization of methyl methacrylate (MMA) with a PHB‐MI/Ce(IV) redox system in aqueous nitric acid at 40°C. Second, PMMA‐PHB‐MI was used in the thermal polymerization of MMA at 60°C to obtain PHB‐b‐PMMA. When styrene (S) was used instead of MMA in the second step, ABCBA‐type PMMA‐b‐PHB‐b‐PS multiblock copolymers [where C is polystyrene (PS)] were obtained. In addition, the direct thermal polymerization of the monomers (MMA or S) via PHB‐MI provided AB‐type diblocks copolymers with MMA and BCB‐type triblock copolymers with S. The macroinitiators and block copolymers were characterized with ultraviolet–visible spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, cryoscopic measurements, and thermogravimetric analysis. The increases in the intrinsic viscosity and fractional precipitation confirmed that a block copolymer had been obtained. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1789–1796, 2004     

Synthesis and solution properties of alternating maleimide/styrene hyperbranched copolymers via controlled radical mechanism

Copolymerizations of (N,N‐diethyldithiocarbamyl)methylstyrene (inimer: DTCS) with maleimide (MI) were carried out under UV irradiation. DTCS monomers play an important role in this copolymerization system as an inimer that is capable of initiating radical polymerization of the vinyl group. Reactivity ratios (r₁ = 0.15 and r₂ = 0) were estimated by the curve‐fitting procedure (DTCS [M₁]; MI[M₂]). These reactivities show strong alternation, and the propagating copolymer radicals proceed with homopolymerization of 1:1 complexes formed between the donor and acceptor monomers. These alternating copolymers exhibit highly branched structure and are actually hyperbranched copolymers. The compact nature of the hyperbranched molecules was demonstrated by comparison of their dilute‐solution properties with those of the linear analogues. The hyperbranched macromolecules behave as single, well‐separated molecules (even in good solvent) and as hard spheres. Copyright © 2003 Society of Chemical Industry     

Copolymerization of methyl methacrylate with 4‐vinylpyridine initiated by a novel Ni(II)α‐Benzoinoxime complex

Copolymerizations of methyl methacrylate (MMA) with 4‐vinylpyridine (4VP) were performed from different monomer feed ratios in 1,4‐dioxan at 30°C under free radical initiation experimental conditions, using Ni(II)α‐Benzoinoxime complex as initiator. The obtained copolymers (PMMA4VP) were examined by FTIR and ¹H NMR spectroscopies. The composition of these copolymers was calculated, using ¹H NMR spectra and elemental analysis. Monomer reactivity ratios were estimated from Fineman–Ross (FR, r_m = 0.550, r_v = 1.165) and Kelen–Tudos (KT, r_m = 0.559, r_v = 1.286) linearization methods, as well as nonlinear error in variables model (EVM) method using the RREVM computer program (RREVM, r_m = 0.559, r_v = 1.264). These values suggest that MMA‐4VP pair copolymerizes randomly. ¹H NMR spectra provide information about the stereochemistry of the copolymers in terms of sequence distributions and configurations. These results showed that the age of the Ni complex has an impact not only on its activity towards polymerization reactions but also on the features of the corresponding copolymers, whereas the chemical composition was insensitive to this prominent factor. The mechanism of MMA‐4VP copolymerization is consistent with a radical process as supported by microstructure and molecular weight distribution studies. Thermal behaviours of these copolymers were investigated by differential scanning calorimetry and thermogravimetric analysis. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Atom transfer radical copolymerization of glycidyl methacrylate and methyl methacrylate

Glycidyl methacrylate (GMA) and methyl methacrylate (MMA) copolymers were synthesized by atom transfer radical polymerization (ATRP). The effect of different molar fractions of GMA, ranging from 0.28 to 1.0, on the polymer polydispersity index (weight‐average molecular weight/number‐average molecular weight) as the indicator of a controlled process was investigated at 70°C, with ethyl 2‐bromoisobutyrate as an initiator and 4,4′‐dinonyl‐2,2′‐bipyridyne (dNbpy)/CuBr as a catalyst system in anisole. The monomer reactivity ratios (r values) were obtained by the application of the conventional linearization Fineman–Ross method (r_GMA = 1.24 ± 0.02 and r_MMA = 0.85 ± 0.03) and by the Mayo–Lewis method (r_GMA = 1.19 ± 0.04 and r_MMA = 0.86 ± 0.03). The molecular weights and polydispersities of the copolymers exhibited a linear increase with GMA content. The copolymer compositions were determined by ¹H‐NMR and showed a domination of syndiotactic structures. The glass‐transition temperatures (T_g) of the copolymers analyzed by differential scanning calorimetry (DSC) decreased in the range 105–65°C with increasing GMA units. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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     

Synthesis of PMMA‐PTHF‐PMMA and PMMA‐PTHF‐PST linear and star block copolymers

Combination of cationic, redox free radical, and thermal free radical polymerizations was performed to obtain linear and star polytetramethylene oxide (poly‐THF)‐polymethyl methacrylate (PMMA)/polystyrene (PSt) multiblock copolymers. Cationic polymerization of THF was initiated by the mixture of AgSbF₆ and bis(4,4′ bromo‐methyl benzoyl) peroxide (BBP) or bis (3,5,3′,5′ dibromomethyl benzoyl) peroxide (BDBP) at 20°C to obtain linear and star poly‐THF initiators with M_w varying from 7,500 to 59,000 Da. Poly‐THF samples with hydroxyl ends were used in the methyl methacrylate (MMA) polymerization in the presence of Ce(IV) salt at 40°C to obtain poly(THF‐b‐MMA) block copolymers containing the peroxide group in the middle. Poly(MMA‐b‐THF) linear and star block copolymers having the peroxide group in the chain were used in the polymerization of methyl methacrylate (MMA) and styrene (St) at 80°C to obtain PMMA‐b‐PTHF‐b‐PMMA and PMMA‐b‐PTHF‐b‐PSt linear and star multiblock copolymers. Polymers obtained were characterizated by GPC, FT‐IR, DSC, TGA, ¹H‐NMR, and ¹³C‐NMR techniques and the fractional precipitation method. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 219–226, 2004     

Synthesis of novel polymethacrylate bearing an (S)‐(+)‐1‐cyclohexylethyl urea group in the side chain and its chiral recognition ability

A new chiral methacrylate, (S)‐(+)‐1‐cyclohexylethyl‐(2‐methacryloyloxyethyl)urea (CEMOU), was synthesized from 2‐methacryloyloxyethyl isocyanate (MOI) and (S)‐(+)‐cyclohexylethylamine. Radical homopolymerization of CEMOU was performed in several solvents to obtain the corresponding chiral polymers having hydrogen bonds based on urea moieties. Specific optical rotations of poly(CEMOU) were slightly changed by the measurement temperature, which may be attributed in part to a change of conformation caused by hydrophobic interaction between the cyclohexyl groups. From the results of radical copolymerization of CEMOU (M₁) with styrene (ST, M₂) or methyl methacrylate (MMA, M₂), monomer reactivity ratios (r₁, r₂) and Alfrey–Price Q–e values were determined: r₁ = 0.89, r₂ = 0.12, Q₁ = 2.45, e₁ = 0.68 for the CEMOU–ST system; r₁ = 0.48, r₂ = 0.18, Q₁ = 8.39, e₁ = 1.97 for the CEMOU–MMA system. The chiroptical property of the poly(CEMOU‐co‐ST) was slightly influenced by the co‐units. Poly(CEMOU)‐bonded silica gel as the chiral stationary phase (CSP) was prepared for high‐performance liquid chromatography (HPLC). The CSP resolved trans‐2‐dibenzyl‐4,5‐di(o‐hydroxyphenyl)‐1,3‐dioxolane in normal phase such as n‐hexane/2‐propanol by HPLC. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1018–1025, 2003     

Free radical copolymerization of N,N‐dimethylaminoethyl methacrylate with styrene and methyl methacrylate: monomer reactivity ratios and glass transition temperatures

BACKGROUND: The properties of copolymers depend strongly on their composition; therefore in order to tailor some for specific applications, it is necessary to control their synthesis, and, in particular, to know the reactivity ratios of their constituent monomers. Free radical copolymerizations of N,N‐dimethylaminoethyl methacrylate (DMAEM) with styrene (ST) and methyl methacrylate (MMA) in toluene solution using 1‐di(tert‐butylperoxy)‐3,3,5‐trimethylcyclohexane as initiator at 70 °C were investigated. Monomer reactivity ratios were determined for low conversions using both linear and nonlinear methods. RESULTS: For the DMAEM/ST system the average values are r₁ = 0.43 and r₂ = 1.74; for the DMAEM/MMA system the average values are r₁ = 0.85 and r₂ = 0.86. The initial copolymerization rate, R_p, for DMAEM/ST sharply decreases as the content of ST in the monomer mixture increases up to 30 mol% and then attains a steady value. For the DMAEM/MMA copolymerization system the composition of the feed does not have a significant influence on R_p. The glass transition temperatures (T_g) of the copolymers were determined calorimetrically and calculated using Johnston's sequence length method. A linear dependence of T_g on copolymer composition for both systems is observed: T_g increases with increasing ST or MMA content. CONCLUSION: Copolymerization reactivity ratios enable the design of high‐conversion processes for the production of copolymers of well‐defined properties for particular applications, such as the improvement of rheological properties of lubricating mineral oils. Copyright © 2009 Society of Chemical Industry     

Morphologies and dynamic mechanical properties of core‐shell emulsifier‐free latexes and their copolymers for P(BA/MMA)/P(MMA/BA) and P(BA/MMA)/PSt systems in the presence of AHPS

Different poly(methyl methacrylate/n‐butyl acrylate)/poly(n‐butyl acrylate/methyl methacrylate) [P(BA/MMA)/P(MMA/BA)] and poly(n‐butyl acrylate/methyl methacrylate)/polystyrene [P(BA/MMA)/PSt] core‐shell structured latexes were prepared by emulsifier‐free emulsion polymerization in the presence of hydrophilic monomer 3‐allyloxy‐2‐hydroxyl‐propanesulfonic salt (AHPS). The particle morphologies of the final latexes and dynamic mechanical properties of the copolymers from final latexes were investigated in detail. With the addition of AHPS, a latex of stable and high‐solid content (60 wt %) was prepared. The diameters of the latex particles are ～0.26 μm for the P(BA/MMA)/P(MMA/BA) system and 0.22–0.24 μm for the P(BA/MMA)/PSt system. All copolymers from the final latexes are two‐phase structure polymers, shown as two glass transition temperatures (T_gs) on dynamic mechanical analysis spectra. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3078–3084, 2002     

Synthesis and characterization of PMMA‐b‐PBMA block copolymers by atom transfer radical polymerization

The synthesis of diblock copolymers using atom transfer radical polymerization, ATRP, of n‐butyl methacrylate, BMA, and methyl methacrylate, MMA, is reported. These copolymers were prepared from 2‐bromoisobutyryl‐terminated macroinitiators of poly(MMA) and poly(BMA), using copper chloride, CuCl,/N,N,N′,N″,N″‐pentamethyldiethylenetretramine, PMDETA, as the catalyst system, at 100°C in bulk and in benzonitrile solution. The block copolymers were characterized by means of size‐exclusion chromatography, SEC, and ¹H‐NMR spectroscopy. The SEC analysis of the synthesized diblock copolymers confirmed important differences in the molecular weight control depending on the reaction medium (solvent effect) and the chemical structure of the macroinitiator used. In addition, differential scanning calorimetry, (DSC) measurements were performed, showing for all the copolymers a phase separation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2683–2691, 2002     

Free‐radical copolymerization and kinetic treatment of methyl methacrylate with N‐P‐tolylmaleimide

The free‐radical copolymerization of methyl methacrylate (MMA) with N‐P‐tolylmalemide (NPTMI) at 77°C in cyclohexanone solution initiated by AIBN was studied. The copolymer composition was calculated from the nitrogen content estimated by the Mico–Kijedldahl's method and by elemental analysis. The reactivity ratios have been calculated by Fineman and Ross method. The monomer reactivity ratios were r_NPTMI = 1.24, r_MMA = 2.1. The glass transition temperature (T_g) of the copolymers were determined by torsion braid analysis (TBA). The thermal stability was determined by thermogravimetric analysis (TGA). T₅₀, temperature at which the weight loss reaches 50%, was abstained. The results showed that the M _n and M _w increased, whereas the NPTMI feed content increased. The T_g and T₅₀ increased dramatically. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 867–870, 2004