Amarnath Banerjee

Study of methyl-methacrylate-viscose fiber graft copolymerization and the effect of grafting on thermal properties

The graft copolymerization of methyl-methacrylate onto viscose fibers was studied under photoactive conditions with visible light using Ce 4+ /Ti 3+ combination as redox initiator in a limited aqueous medium. Polymerization conducted in the presence of light at 30 ± 1°C produced significant grafting, compared with that conducted in the dark under the same conditions. The % grafting, % total conversion, and % grafting efficiency were studied by varying time, monomer concentration, initiator concentration, and pH of the medium. The mechanism of polymerization and graft copolymer formation have been discussed. Characterization of the grafted fibers was done by Fourier transform infrared spectroscopy and scanning electron microscopy. The effect of % grafting on thermal properties was studied by thermogravimetric analysis.

Rheological and Mechanical Properties of LDPE/HDPE Blends

Melt rheology and mechanical properties of binary blend of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) have been investigated. Four different wt fractions of blends containing LDPE/HDPE (20/80, 40/60, 60/40, and 80/20) were prepared. Cole-Cole plots [storage melt viscosity (η′) vs. loss melt viscosity (η″)] and relation between storage melt viscosity (η′) with frequency (ω) and blend composition were constructed. Miscibility of blends was established from rheological data. Impact strength of the blends increased with increasing LDPE concentration, whereas tensile strength shows the opposite trends. Percentages of the crystallinity of the blends were calculated by both the differential scanning calorimetry and wide-angle X-ray scattering methods, which show that the percentage of crystallinity decreased with increasing LDPE concentration, but the rate of crystallization of HDPE phase was unaffected.

High-Density Polyethylene-Ethylene Propylene Rubber-Based Thermoplastic Elastomer: A Mechanical Modeling, Thermal and Rheological Study

The present investigation deals with the mechanical, thermal and rheological properties of binary HDPE/EPR blends at various dispersed phase (EPR) concentrations. The effects of EPR concentration on tensile, impact properties of the pure HDPE and HDPE/EPR blends were studied. Analysis of the tensile data in terms of various theoretical models revealed the variation of stress concentration effect with blend composition. Rheological study was carried out to investigate the change in viscosity with shear rate. DSC results show decrease in percent crystallinity of HDPE upon incorporation of EPR except at 20 wt% rubber concentrations wherein the percent crystallinity has shown marginal increment.

Mechanical property studies of poly(methyl methacrylate)‐grafted viscose fibers

Graft copolymerization of methyl methacrylate (MMA) on viscose fibers (grade 1.5 x 51 mm; Nagda; grey staple; bright bleached) was studied under a photoactive condition with visible light using conventional Mohrs salt-potassium persulphate as the redox initiator. The mechanical properties of the grafted viscose fiber, such as tenacity, breaking extension, and initial modulus were studied. The effect of monomer-solvent combination on viscoelastic nature (elasticity work recovery and stress relaxation) of the grafted fibers have also been explained. The moisture regain characteristics of the grafted fibers were also studied.

Kinetic Investigation on the Photopolymerization of Methyl Methacrylate Using Iodine Trichloride as Initiator

Abstract The photopolymerization of MMA in visible light was studied at 45°C using IC13 as the photoinitiator. The initiator exponent was found to be 0.16 and the monomer exponent varied between 1.0 to 1.50, depending on the nature of the solvent. Analysis of the data revealed that the polymerization was induced by a free radical mechanism. Nonideality of the kinetics was explained on the basis of 1) Monomer-dependent chain initiation and 2) Initiator-dependent chain termination via degradative initiator transfer.

Effect of compatibiliser and fibre content on jute fibre reinforced HDPE/EPDM: A dynamic mechanical and thermal study

The thermal and dynamic mechanical properties of jute fibre reinforced high density polyethylene (HDPE)/ ethylene-propylene-diene terpolymer (EPDM) composites were studied. The fibre loading was varied between 10 and 30 wt%, and at each fibre loading, four compatibiliser doses were used. Dynamic parameters (storage flexural modulus (E), loss flexural modulus (E”), loss factor or damping efficiency (tanδ) were determined in a resonance frequency mode. The storage modulus increased with increasing fibre content and a further increase was observed with the addition of compatibiliser. The tanδ was decreased by an increase in fibre content because of the restricted mobility of the polymer chains caused by the fibres. A marginal shifting of the transition was observed with an increase in the compatibiliser dose at constant e fibre loading. A low concentration of fibre increased the crystallinity of HDPE because it acted as a nucleating agent.

Effect of compatibiliser and fibre content on jute fibre reinforced HDPE/EPDM composites

The mechanical and morphological properties of jute fibre reinforced high-density polyethylene (HDPE)/ethylene-propylene-diene terpolymer (EPDM) composites were studied as a function of fibre and compatibiliser content. A remarkable improvement in tensile strength, flexural strength and unnotched impact strength was attained with addition of 2% compatibiliser. With increasing fibre content, the tensile and flexural strength increased but impact strength declined because of the presence of too many fibre ends that could cause crack initiation. Scanning electron microscopy showed that better interaction and distribution of fibres in the matrix was achieved in the compatibilised system than the uncompatibilised one.