Bhikhu Suthar

Interpenetrating polymer networks from castor oil-based polyurethane and poly(ethyl methacrylate) XVII

Abstract Two-component interpenetrating polymer networks (IPNs) of castor oil-based polyurethane (PU) and poly(ethyl methacrylate) (PEMA) were prepared by sequential polymerization. The liquid polyurethanes were formed by reacting the hydroxyl group of castor oil with isophorone diisocyanate at different NCO/OH ratios. These polyurethanes were swollen in ethyl methacrylate monomer, which was subsequently polymerized by radical polymerization initiated with benzoyl peroxide in the presence of crosslinkers, ethylene glycol dimethacrylate and 1,3-propanediamine. A series of PU/PEMA interpenetrating polymer networks (IPNs) were obtained as tough films. These IPNs were characterized in terms of: resistance to chemical reagents, thermal behaviour and dynamic mechanical thermal analysis. The morphology was determined by scanning electron microscopy, and dielectric properties at different temperatures were studied.

Interpenetrating polymer networks from castor oil based polyurethanes and poly(methyl acrylate)—IV

Abstract Castor oil and toluene-2,4-diisocyanate were reacted to form liquid prepolyurethane under various experimental conditions, varying the NCO/OH ratio. The prepolyurethanes (PPU) thus obtained were interpenetrated with methylacrylate monomer containing ethylene glycol dimethacrylate, using radical polymerization initiated by benzoyl peroxide. The PPU/MA interpenetrating polymer networks were obtained as transparent tough films by transfer moulding. They were characterized by resistance to chemical reagents, thermal behaviour and mechanical properties. The mechanothermal behaviour was studied by dynamic mechanical analysis. The morphology was examined by Scanning Electron Microscopy. Dielectric properties were studied.

Polychelates from Poly(m-N-Acryloyl-Aminobenzoic Acid)

Abstract Polychelates of Fe(II), Co(II), Ni(II), Cr(III), UO2(II), VO(II) and Zn(II) were prepared from poly(m-N-acryloylaminobenzoic acid). All the polyehelates were characterized by elemental analysis, diffuse reflectance spectra, magnetic susceptibility measurements, IR spectral data and conductivity measurements. All these polychelates are intensely colored, non-electrolytes and insoluble in common organic solvents. All these polychelates show a six coordinated structure and octahedral stereochemistry. From thermogravimetric analysis, the thermal stability of all polychelates was determined.

Thermal stability of castor oil-based interpenetrating polymer networks

Abstract Two-component sequential-interpenetrating polymer networks (IPNs) from castor oil-based polyurethanes and poly(methyl methacrylate) have been prepared. Component I-polyurethane was formed by reacting the hydroxyl functionality of castor oil with different diisocyanates in the stoichiometric NCO/OH ratio of 1.6. These polyurethanes were mixed individually with methyl methacrylate monomer and subsequently an interpenetrating network prepared by free radical polymerization initiated by benzoyl peroxide in the presence of crosslinking agent. The interpenetrating polymer networks, PU/PMMA IPNs, were moulded into tough and transparent films. The thermal stability of these IPNs was assessed by thermogravimetric analysis.

Interpenetrating Polymer Networks from Castor Oil Based Polyurethanes and Poly(Methyl Methacrylate) XX

Abstract Two component interpenetrating polymer networks (IPNs) of castor oil based polyurethanes and poly(methyl methacrylate) were prepared by sequential polymerization. The liquid polyurethanes were formed by reacting the hydroxyl group of castor oil with diphenyl methane diisocyanate at different stoichiometric NCO/OH ratios. These polyurethanes were swollen in methyl methacrylate monomer and subsequently polymerized by radical polymerization initiated with benzoyl peroxide in presence of crosslinkers ethylene glycol dimethacrylate and 1,3-propanediamine. Novel interpenetrating polymer networks PU/PMMA IPNs were obtained as films by transfer molding technique. These IPNs were characterized in terms of crosslink density and mechanical properties. The morphology was studied by transmission electron microscopy. Thermal stability was assessed from the thermogravimetric data.

Interpenetrating Polymer Networks from Castor Oil Based Polyurethanes and Poly(methyl methacrylate). XIII

Abstract Polyurethanes were obtained by the reaction of the hydroxyl group of castor oil with isophorone diisocyanate under different stoichiometric ratios of NCO/OH. A series of polyurethane-poly(methyl methacrylate) simultaneous interpenetrating polymer networks (PU/PMMA IPNs) of different compositions were synthesized as tough films by casting from glass molds. These IPNs were investigated using their resistance to chemical reagents, thermal behavior, tensile strength, Youngs modulus, elongation at break (%), and Shore A hardness. The dielectric properties (σ, ∊′, ∊″ and tan δ) at different temperatures were studied. Electron microscopy confirmed the phase separation.

Water-insoluble polyacrylamide. II. Kinetics of free-radical polymerization of o-N-acryloylaminobenzoic acid

Abstract Synthesis of water-insoluble poly(o-N-acryloylaminobenzoic acid) was investigated by free radical polymerization. Kinetics of polymerization of o-N-acryloylaminobenzoic acid (OAB) initiated by 2,2′-azoisobutyronitrile (AIBN) in dioxane was studied at 78–100°C. The rate of polymerization was evaluated by varying the concentration of monomer and initiator. The rate of polymerization was found to increase steadily with increasing monomer concentration. The overall activation energy was found to be 9.8 kcal/ mol. A suitable kinetic scheme is proposed, and a rate equation has been derived.

Water insoluble polyacrylamide. V: Dilute solution properties of poly (N-acryloyl-o-aminobenzoic acid)

Abstract A high molecular weight poly( N -acryloyl- o -aminobenzoic acid) has been synthesized by radical polymerization in a mixed solvent medium. The polymer has been fractionated by fractional precipitation and the fractions characterized by viscometry, vapour pressure osmometry and gel permeation chromatography. Mark-Houwink-Kuhn-Sakurada relationships are developed for three solvents. The values of unperturbed dimensions, (〈 R 0 2 〉/ M ) 0.5 , are evaluated by application of two-parameter theories of the excluded volume effect, developed by Fixman, Kurata, Stockmayer and Roig and by Bueche and James and first order perturbation theory. Based on the value of the conformational parameter σ, the polymer is found to behave as a semiflexible polymer in solution as a result of the increased bulk of the lateral group.

Room-temperature kinetics of formation of castor-oil-based polyurethane/poly(methyl methacrylate) interpenetrating polymer networks

Infrared spectroscopy was used to follow the kinetics of formation of castor-oil-based polyurethane/poly(methyl methacrylate) interpenetrating polymer networks (PU/PMMA IPNs) at room temperature. The synthesis of the individual networks, PU, PMMA and IPNs was studied by measuring the decrease of characteristic absorption peaks of each system.

N-Acryloyl-o-aminobenzoic Acid and Styrene Copolymer-III. Application of Different Methods for Intrinsic Viscosity and Viscosity Constant Determination:

A high molecular weight copolymer of N-acryloyl-o-aminobenzoic acid (OAB) and styrene has been prepared by radical polymerization using benzoyl peroxide initiator in dioxane solvent. The copolymer has been fractionated by fractional precipitation and the fractions characterized by viscometry, vapour pressure osmometry and gel permeation chromatography. Mark-Houwink-Kuhn-Sakurada (MHKS) relationships are developed for three different solvents. Both the intrinsic viscosities and the viscosity constants of eight PO-PS fractions were obtained by the Huggins, Kraemer, Martin and Schulz-Blaschke methods in dimethyl formnamide, toluene and tetrahydrofuran solvents. It was concluded that the values obtained by these four methods are in close agreement.