N‐Vinylpyrrolidone and Ethoxyethyl Methacrylate Copolymer: Synthesis,Characterization and Reactivity Ratios

Free radical copolymerization of N‐vinyl‐2‐pyrrolidone with 2‐ethoxyethyl methacrylates was carried out with 2,2′‐azobisisobutyronotrile as an initiator in 1,4‐dioxane. The resulting copolymer was characterized by FTIR, H¹‐NMR and C¹³‐NMR spectroscopic techniques thermal properties of copolymer were determined by DSC and TGA. The reactivity ratios of the monomers were computed by the Fineman‐Rose (F‐R), Kelen‐Tudos (K‐T) and extended Kelen‐Tudos (EK‐T) method at lower conversion, using the data obtained from both FTIR and elemental analysis studies; the results are in good agreement with each other. The average reactivity ratio, Alfrey‐Price Q and e values were found to be r ₁=0.769, r ₂=0.266 and Q ₁=0.0859, e ₁=0.4508, respectively for NVP/EOEMA copolymer. The distribution of monomer sequence along the copolymer chain was calculated using a statistical method based on obtained reactivity ratio. The number average molecular weight and polydispersity were determined by GPC.     

Copolymers of α-Methylstyrene with N-Cyclohexylacrylamide: Synthesis,Monomer Reactivity Ratios,and Mean Sequence Length

Abstract

Copolymerization of α-methylstyrene and N-cyclohexylacrylamide was carried out in toluene at 60 ± 1°C using azobisisobutyronitrile as the free-radical initiator. The total concentration of the comonomers was 1.5 mol·L^?1 in the solvent. The copolymers were characterized by ¹H-NMR and ¹³C-NMR spectroscopy, and the copolymer compositions were determined primarily from the ¹H-NMR spectra. The reactivity ratios were found to be r ₁ = 0.08 ± 0.01 and r ₂ = 2.45 ± 0.03 by the Fineman-Ross method, and r ₁ = 0.06 ± 0.01 and r ₂ = 2.43 ± 0.08 by the Kelen-Tüdös method. Mean sequence lengths in the copolymer were estimated from r ₁ and r ₂ values.     

Copolymerization of 4‐Propanoylphenyl Acrylate with Methyl Methacrylate: Synthesis,Characterization and Reactivity Ratios

The new acrylic monomer 4‐propanoylphenyl acrylate (PPA) was synthesized and copolymerized with methyl methacrylate (MMA) in methyl ethyl ketone at 70±1°C using benzoyl peroxide as a free radical initiator. The copolymers were characterized by FT‐IR, ¹H‐NMR and ¹³C‐NMR spectroscopic techniques. The compositions of the copolymers were determined by ¹H‐NMR analysis. The reactivity ratios of the monomers were determined using Fineman‐Ross (r₁=0.5535 and r₂=1.5428), Kelen‐Tüdös (r₁=0.5307 and r₂=1.4482), and Ext. Kelen‐Tüdös (r₁=0.5044 and r₂=1.4614), as well as by a nonlinear error‐in‐variables model (EVM) method using a computer program, RREVM (r₁=0.5314 and r₂=1.4530). The solubility of the polymers was tested in various polar and non‐polar solvents. The elemental analysis was determined by a Perkin‐Elmer C‐H analyzer. The molecular weights (M_w and M_n) of the copolymers were determined by gel permeation chromatography. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with an increase in the mole fraction of MMA in the copolymers. Glass transition temperatures of the copolymers were found to increase with an increase in the mole fraction of MMA in the copolymers.     

Copolymers of 2‐[(5‐Methylisoxazol‐3‐yl)amino]‐2‐oxo‐ethyl Methacrylate with Ethyl Methacrylate: Monomer Reactivity Ratios,Thermal Properties and Antimicrobial Activity

We report the monomer reactivity ratios for copolymers of ethyl methacrylate (EMA) and a reactive monomer, 2‐[(5‐methylisoxazol‐3‐yl)amino]‐2‐oxo‐ethyl methacrylate (IAOEMA), using the Fineman‐Ross, Kelen‐Tüdös, and a nonlinear error invariable model method using a computer program RREVM. Copolymers were obtained by radical polymerization initiated by α,α'‐azobisisobutyronitrile in 1,4‐dioxane solution and were analyzed by FTIR, ¹H‐NMR, and gel permeation chromatography. Elemental analysis was used to determine the molar fractions of EMA and IAOEMA in the copolymers. The reactivity ratios indicated a tendency toward ideal copolymerization. The polydispersity indices of the polymers determined using gel permeation chromatography suggest a strong tendency for chain termination by disproportionation. Thermal behaviors of copolymers with various compositions were investigated by differential scanning calorimetry and thermogravimetric analysis. It was observed that glass transition temperature of copolymers increased with increasing of IAOEMA content in copolymers. Also, the apparent thermal decomposition activation energies (ΔE_d) were calculated by Ozawa method using the SETARAM Labsys TGA thermobalance. The homo‐ and copolymers were tested for their antimicrobial properties against selected microorganisms. All the products show moderate activity against different strains of bacteria, fungi and yeast.     

Copolymers of 2‐(3‐(6‐tetralino)‐3‐methyl‐1‐cyclobutyl)‐2‐Hydroxyethyl Methacrylate with Acrylonitrile and 4‐Vinylpyridine: Synthesis,Characterization, and Monomer Reactivity Ratios

The copolymerization of 2‐(3‐(6‐tetralino)‐3‐methyl‐1‐cyclobutyl)‐2‐hydroxyethyl methacrylate (TCHEMA), monomer with acrylonitrile and 4‐vinylpyridine were carried out in 1,4‐dioxane solution at 65°C using AIBN as an initiator. The copolymers were characterized by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopic techniques. Thermal properties of the polymers were also studied by thermogravimetric analysis and differential scanning calorimetry. The copolymer compositions were determined by elemental analysis. The monomer reactivity ratios were calculated by the Fineman‐Ross and Kelen‐Tüdös method. Also, the apparent thermal decomposition activation energies were calculated by the Ozawa method with a Shimadzu TGA 50 thermogravimetric analysis thermobalance.     

Copolymers of 4‐(3′,4′‐Dimethoxycinnamoyl)phenyl Acrylate and MMA: Synthesis,Characterization, Photocrosslinking Properties,and Monomer Reactivity Ratios

Abstract

4‐(3′,4′‐Dimethoxycinnamoyl)phenyl acrylate (DMCPA) containing pendant chalcone moiety was copolymerized with methyl methacrylate (MMA) by radical polymerization in ethyl methyl ketone at 70°C under a nitrogen atmosphere using benzoyl peroxide (BPO) as a free radical initiator. The prepared polymer was characterized by UV, FT‐IR, ¹H‐NMR, and ¹³C‐NMR spectra. The composition of the copolymer was determined using ¹H‐NMR analysis. The monomer reactivity ratios of copolymerization were determined using conventional linearization methods such as Fineman–Ross (r ₁ = 0.26 and r ₂ = 0.61), Kelen–Tudos (r ₁ = 0.26 and r ₂ = 0.61), and Ext. Kelen–Tudos (r ₁ = 0.23 and r ₂ = 0.59), and a non‐linear error‐in‐variables model (EVM) method using the computer program RREVM (r ₁ = 0.2541 and r ₂ = 0.6094). The molecular weights (M _w and M _n) of the copolymers were determined by gel permeation chromatography. Thermogravimetric analysis of the polymers in air reveals that the stability of the copolymers decreases with an increase in the mole fraction of MMA in the copolymers. The solubility of the polymers was tested in various polar and non‐polar solvents. The glass transition temperature of the copolymers was determined as a function of copolymer composition. The copolymers were sensitive to UV light and became crosslinked after irradiation with 254 nm light.     

Synthesis of Copolymers of Unsaturated β-Diketones with Styrene and Methyl Methacrylate

Copolymerization of styrene and methyl methacrylate with various unsaturated -diketones was studied. The influence exerted by the reaction temperature, structure of -diketone, and its content in the comonomer mixture on the kinetic parameters of copolymerization and molecular weights of the products was examined.     

Synthesis of Copolymers of Methacrylate BearingAminonitro┐StilbeneDyesandTheirNonlinearOpticalProper

报道了含ａｍｉｎｏｎｉｔｒｏ－ｓｔｉｌｂｅｎｅ基团的甲基丙烯酸酯类单体的合成、该单体与ＭＭＡ的共聚反应及对所得聚合物进行的非线性光学性能测定。结果表明，缩短ｓｔｉｌｂｅｎｅ片段与甲基丙烯酰基的连接链长有助于改善单体的聚合性能，增强聚合物在有机溶剂中的溶解能力。对所得聚合物的ＳＨＧ测定显ｄ３３值可达到５４ｐｍ／ｖ。     

Free-Radical Copolymerization of Methyl Methacrylate and α-Methacrylophenone. I. Reactivity Ratios

The free-radical copolymerization of methyl methacrylate and methacrylophenone (MAP) initiated by azobisisobutyroni-trile at 60°C has been studied in ethylbenzene solution and in bulk. The process is characterized by a competitive Diels-Alder condensation of methacrylophenone and by a very low reactivity of methacrylophenone-terminated macroradicals in propagation reactions. The experimental composition data are consistent with a terminal unit model: r_A = 1.77 ± 0.02, r_B = 0.110 ± 0.006. Copolymerization with depropagation of methacrylophenone-terminated growing chains and copolymerization affected by penultimate effects have been tested as optimized possible models to take into account the inability of MAP to undergo homopolymerization.     

Synthesis and Application of Chitosan‐g‐PLLA Copolymers

The purpose of this paper is to study the synthesis and application of a new type of chitosan‐g‐poly(L‐lactide) copolymer with different grafting percentage in the presence of triethylamine. FTIR and ¹H NMR results indicate that grafting percentage of graft copolymers increases with the molar feeding ratio of L‐lactide to chitosan. The measurement of XRD and TG shows that graft copolymer exhibits low crystallinity and thermal degradation temperature. Static water contact angle testing suggests that graft copolymer has superior hydrophilicity compared with PLLA, which can be very useful for biomedical applications. 5‐Fluorouracil loaded copolymer microspheres were prepared by phase separation method. The size and distribution of microspheres were measured by a Laser particle analyzer. The microspheres with LLA:CS feeding molar rotio (15∶1) have a mean diameter of 332 nm with a narrow unimodal distribution. The spherical microspheres were observed by transmission electron microscopy (TEM). The microspheres shows good releasing property from drug release in vitro, and the drug release rate decreases as the increase of microspheres size.     

N‐Chlorosulfonyloxazolidin‐2‐ones: Synthesis,Structure, and Reactivity Toward Aminoesters

Abstract

Synthesis, structure, and reactivity of chiral N‐chlorosulfonyloxazolidin‐2‐ones are described. Their synthesis were easily carried out starting from the corresponding chiral oxazolidin‐2‐ones and sulfuryl chloride to afford the title compounds 1 in high yields.     

Synthesis and Radical Polymerization of N‐[4‐N′‐(Phenylamino‐carbonyl)phenyl]maleimide and its Copolymerization with Methyl Methacrylate

A novel type of imide‐amide monomer, 4‐maleimidobenzanilide (MB) i.e., N‐[4‐N′‐(phenylaminocarbonyl)phenyl]maleimide was synthesized from maleic anhydride, p‐aminobenzoic acid and aniline. Radical polymerization of MB and its copolymerization with MMA (methyl methacrylate), initiated by AIBN, were performed in THF solvent at 65°C. Nine copolymer samples were prepared using different feed ratios of comonomers. All the polymer samples have been characterized by a solubility test, intrinsic viscosity measurements, FT‐IR and ¹H‐NMR spectral analysis, and thermo‐gravimetric analysis. The values of monomer reactivity ratios of MB‐MMA system (r₁, r₂) and the Alfrey‐Price parameters Q₁ and e₁ were determined.     

Relationship between Reactivity Ratios and Configuration for Donor—Acceptor Type Copolymers

For binary copolymers from an acrylic monomer (acceptor type, M¹) and an aromatic-substituted monomer (donor type, M₂) a linear relation between log (r₂/r¹) and the probability of “coisotactic” alternating addition is observed. This can be a proof for the influence of monomer polarity on the copolymer configuration.     

2,4‐Dichlorophenyl Acrylate/8‐Quinolinyl Methacrylate Copolymers: Ion‐Exchange Study

The chelating ion‐exchange properties of the 2,4‐dichlorophenyl acrylate (2,4‐DCPA)/8‐quinolinyl methacrylate (8‐QMA) copolymers, synthesized using different monomer feed ratios, were investigated by the batch equilibrium method. Five metal ions Cu⁺², Ni⁺², Co⁺², Zn⁺², and Fe⁺³ were used to evaluate the cation‐exchanger capability of 2,4‐DCPA‐co‐8‐QMA copolymers. The ion‐exchange study was carried out for three different experimental variables viz., pH of the aqueous medium, ionic strength of electrolyte and shaking time. It was observed that due to the presence of a pendant ester‐bound quinolinyl group, the copolymers are better suited as cation exchangers.     

Free Radical Copolymerization of N‐(4‐Carboxyphenyl)maleimide with Hydropropyl Methacrylate

Abstract

The free radical copolymerization of N‐(4‐carboxyphenyl)maleimide (CPMI) (M₁) with hydropropyl methacrylate (HPMA) (M₂) was carried out with 2,2′‐azobis(isobutyronitrile) (AIBN) as an initiator in ethyl acetate at 75°C. The composition of copolymer prepared at low conversion was determined by elemental analysis. The monomer reactivity ratios were found to be r ₁?=?0.31 and r ₂?=?1.11 as determined by the YBR equation. The number‐average molecular weight and polydispersity were determined by gel permeation chromatography (GPC). Furthermore, the solvent effect on this copolymerization system was also investigated. The resulting copolymer was characterized by FTIR and ¹H‐NMR spectroscopy. The thermal stability of copolymers was determined by thermogravimetric analysis (TGA). It was found that the copolymer shows step‐by‐step degradation, the initial decomposition temperature (T _i), and final decomposition temperature (T _f) increased with increasing the component of CPMI in copolymer.     

Superoxide‐Mediated Synthesis of N‐Aminoaziridines from N‐Aminoheterocycles and Olefins

Oxidation of 3‐amino‐2‐methyl‐4(3H)‐quinazolone and N‐aminophthalimide by superoxide ion generated in situ in the presence of olefinic substrates gives rise to the formation of N‐aminoaziridine derivatives.     

Reactivity Ratios of Diethyldiallylammonium Chloride with Acrylamide or Acrylic Acid

The compositions of copolymers of diethyldiallylammonium chloride (DEDAAC) with acrylamide (AM), acrylic acid (AA) or sodium acrylic acid (NaAA) at low conversion were determined by elemental analysis, and the reactivity ratios of monomers in copolymerization were obtained by Kelen-Tudos method. The results showed that the reactivity ratios rDE and rAM are 0.31 and 5.27 for DEDAAC with AM, rDE and rAA are 0.28 and 5.15 for DEDAAC with AA, and rDE and rNaAA are 0.40 and 3.97 for DEDAAC with NaAA, respectively. The copolymerizations for DEDAAC with AM, AA or NaAA are non-ideal copolymerization and the products are random copolymers.     

Reaction of N‐Nonaflyl and N‐Cyano‐Benzotriazoles with Enamines

N‐Nonaflyl‐benzotriazole 1a reacts with enamines 2 in tetrahydrofurane (THF) at room temperature to afford o‐nonafluorobutansulfonamido‐phenylazo‐enamines 3 in 74–81% yield. Compound 1a reacts with 1‐diethylaminobutadien 2f twice, affording pyridazine derivative 3f in 20% yield. Ringopening of N‐cyano‐benzotriazole 1b with pyrrolidinocyclohexene 2a affords, under cleavage of pyrrolidine 1,2,3,4‐tetrahydro‐dibenzo[4,5:e]imidazo[1,2‐b][1,2,4]triazine 4 in 43% yield.     

Synthesis of Z‐N‐Alkenylformamides

Commercially available difluorinated benzaldehyde was converted to the Z‐N‐alkenylformamides via Horner–Emmons olefination and Curtius rearrangement, followed by reduction with tri‐tert‐butoxy‐aluminohydride.     

Synthesis and NMR Characterization of Multi‐hydroxyl End‐groups PEG and PLGA‐PEG Barbell‐like Copolymers

Multi‐hydroxyl end‐groups poly(ethylene glycol) (PEG) was prepared from PEG and epichlorohydrin. Then, PEG‐supported poly(lactic‐ran‐glycolic acid) (PLGA)_n‐PEG‐(PLGA)_n (n=1, 2, 4) linear‐dendritic barbell‐like copolymers were synthesized through direct polycondensation under bulk condition from the multi‐hydroxyl end‐groups PEG, lactic acid and glycolic acid. Arm numbers were varied, with 2, 4 and 8, by using bis‐, tetra‐, and octa‐hydroxyl end‐groups PEG, respectively. The chemical structures, absolute number‐average molecular weight, the monomer units per single arm and the molar ratio of hydroxyl acid monomer units of the (PLGA)_n‐PEG‐(PLGA)_n barbell‐like copolymers were analyzed by NMR spectroscopy. The result indicated that the structures of the multi‐hydroxyl end‐groups PEG and (PLGA)_n‐PEG‐(PLGA)_n barbell‐like copolymers were consistent with design. Compared with the theoretical values, molecular weights determined by ¹H‐NMR end‐group analysis gave reasonably consistent values, but the values determined by gel permeation chromatography (GPC) were considerably less than theoretical values. The results indicated that (PLGA)_n‐PEG‐(PLGA)_n copolymers have linear‐dendritic structures.