B.S.R. Reddy

Copolymerization of 4-methyl- and 4-methoxyphenyl acrylates with glycidyl methacrylate: Synthesis, characterization, reactivity ratios, and application as adhesives for the leather industry

Copolymers of 4-methyl- and 4-methoxyphenyl acrylates with glycidyl methacrylate having different copolymer compositions were synthesized in 1,4-dioxan using benzoyl peroxide as a radical initiator at 70 ± 0.5°C. The composition of the monomers in the copolymers were calculated using 1H-NMR spectroscopy by comparing the integral values of well-separated aromatic and alifatic proton peaks. The reactivity ratios were calculated by Fineman-Ross, Kelen-Tudos, and extended Kelen-Tudos methods. The copolymers were characterized by 1H-NMR and proton decoupled 13C-NMR spectroscopic techniques. Gel permeation chromatography was used for determining the and and polydispersity indexes of the copolymers. Thermal stability of the homo- and copolymers was calculated using thermogravimetric analysis, while differential scanning calorimetry was utilized in determining the glass transition temperature. Copolymers of suitable composition were chosen for curing reactions with diethanolamine in chloroform. The cured resins were tested as adhesives for leather-leather bonding at different temperatures (50, 90, 100, and 110°C). It was found that copoly(MOPA-GMA) at 50°C gave the best adhesive property over all other samples tested.

Copolymerization of 4-chlorophenyl acrylate with methyl acrylate: synthesis, characterization, reactivity ratios, and their applications in the leather industry

4-Chlorophenyl acrylate (CPA) was prepared by reacting 4-chlorophenol and acryloyl chloride in the presence of triethylamine in ethyl acetate solution. Poly(4-chlorophenyl acrylate) and copoly(4-chlorophenyl acrylate-methyl acrylate) were synthesized by the free radical polymerization in ethyl acetate at 70°C. All the polymers were characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopic techniques. The composition of the copolymers was determined by the 1 H-NMR spectroscopic technique, that is, by integrating the aromatic peaks corresponding to the 4-chlorophenyl acrylate unit against the carbomethoxy group in the methyl acrylate unit. The reactivity ratios were calculated by Fineman-Ross, Kelen-Tudos (K-T), and the extended Kelen-Tudos methods. The values of r 1 and r 2 obtained by these methods were in close agreement with each other; that is, r 1 (CPA) = 0.64 and r 2 (MA) = 0.13 by the K-T method. The number-average molecular weight (M n = 1.55 × 10 3 ), the weight-average molecular weight (M w = 8.39 × 10 3 ), and the polydispersity index (M w /M n = 5.42) of poly(CPA) were determined by gel permeation chromatography (GPC). Thermal properties of the polymers were studied in a nitrogen atmosphere using thermogravimetric analysis (TGA). As the CPA increases in the copolymer, thermal stability of the copolymer increases (e.g., 90% weight loss occurs at 480°C for 20 mol % CPA, whereas the same weight loss occurs at 571°C for 80 mol % CPA). Acrylic binders, based on the CPA-MA-BA terpolymer, of different glass transition temperatures were prepared for applications in leather industry as top coat and base coat materials. These acrylic emulsions were cast into thin films, and their characteristics were tested for physical properties. These acrylic emulsions were applied as a base coat on leather, and the compositions having T g values of 1.08 and 9.25°C were found to have excellent properties as base coats for leather when compared with commercial samples.

Synthesis, characterization and the reactivity ratios of copolymers of cyclohexyl acrylate with styrene and N-vinyl-2-pyrrolidone

Copolymerization of cyclohexyl acrylate (CHA) with styrene (Sty) and N-vinyl-2-pyrrolidone (VPD) was carried out in benzene and dioxane at 70°C and 75°C, respectively, using benzoyl peroxide as initiator. The copolymers were characterized by i.r., 1H n.m.r., g.p.c. and viscometry. The compositions of the copolymers were determined by elemental analysis and the reactivity ratios were computed by Fineman-Ross, Kelen-Tudos and extended Kelen-Tudos methods. rCHA = 0.272 ± 0.048, rSty = 0.913 ± 0.107 for CHA-Sty system and rCHA = 1.297 ± 0.088, rVPD = 0.122 ± 0.014 for CHA-VPD system are determined by extended Kelen-Tudos method. The Q and e values for CHA monomer were also determined.

Phenyl methacrylate-glycidyl methacrylate copolymers: synthesis, characterization and reactivity ratios by spectroscopic methods

The free-radical polymerization of phenyl methacrylate and glycidyl methacrylate was carried out at 70°C in the presence of benzoyl peroxide using 2-butanone as the solvent. The copolymer compositions of seven copolymer samples with different feed compositions as well as the tacticities were determined by 1H nuclear magnetic resonance spectroscopy. The results were used to calculate the reactivity ratios by the Kelen-Tudos method, which were found to be r1 = 1.57 ± 0.56 and r2 = 0.84 ± 0.51. The homo- and copolymers were also characterized by Fourier-transform infra-red and 13C nuclear magnetic resonance spectroscopic methods. Mw, Mn and polydispersity indices of the copolymers were determined using gel permeation chromatography.

Adsorption and emulsification properties of amphiphilic poly(styrene-co-octadecyl maleamic acid salt) with comb-like architecture.

Amphiphilic poly(styrene-co-octadecyl maleamic acid salt) (PS-co-ODMAS) with a comb-like architecture was synthesized employing a heterophase aqueous polymerization reaction. The side-chain comonomer from octadecyl maleamic acid salt exhibited hydrogelation characteristics and provided conditions for a controlled polymerization reaction. PS-co-ODMAS polymers consisting of 5 and 10 mol% side-chain monomer showed a high molecular weight on the order of 10(6) and narrow polydispersity index at 1.33+0.02. The polymer consisting of 10 mol% side-chain monomer was shown to exhibit properties that are significantly different from those with 5 mol%, and the control poly(styrene) synthesized using sodium dodecyl sulfate surfactant. The polymer consisting of 10 mol% side-chain monomer formed hollow spherical spheres of 30 nm size. It also showed close-packed structures of the side-chain monomer on the polymer surface. Detailed adsorption studies at the liquid/liquid interface were carried out to evaluate and understand the scope for modification in surface energy characteristics of polymers in the presence of additives drawn from simple surfactants. Triton X-100 was shown to undergo effective adsorption on the polymer consisting of 10 mol% side-chain monomer and thus could generate stable emulsions with different volume fractions of heptadecane. The results from electron microscopy studies and viscosity of emulsions are discussed.

Copolymerization of 4-Nitrophenyl acrylate with glycidyl methacrylate : Synthesis, characterization, and reactivity ratios

4-Nitrophenyl acrylate (NPA) was prepared and characterized by IR and NMR spectroscopic techniques. Poly(4-nitrophenyl acrylate) [poly(NPA)] and copolymers of glycidyl methacrylate ( GMA) and NPA having various feed compositions in a 2-butanone solution using benzoyl peroxide as an initiator at 65°C ± 0.5°C were prepared. Copolymer compositions were determined by 1 H-NMR analysis. The monomer reactivity ratios were determined by Fineman-Ross, Kelen-Tudos, and extended Kelen-Tudos methods. The molecular weights of the polymers were determined by gel permeation chromatography. Thermogravimetric analysis of the polymers was performed in air and their thermal stability was studied.