Sadhan De - Profile on Academia.edu (original) (raw)
Papers by Sadhan De
Journal of Materials Science, 1990
The electrical conductivity of pressure-sensitive nitrile rubber composites, containing different... more The electrical conductivity of pressure-sensitive nitrile rubber composites, containing different Ioadings of particulate carbon black filler and short carbon fibre, have been studied. The conductivity of composites increases with increasing of filler concentration as well as with increased applied pressure up to a certain limit. The composites containing particulate fillers register low conductivity as compared to composites containing short carbon fibres, due to easy formation of an interconnecting network in the latter case. The effect of the orientation of short carbon fibre with respect to an applied electric field has also been studied. The pressure dependence of composites with transversely oriented carbon fibres with respect to electric fields is higher than that of composites with longitudinally oriented carbon fibres. The results are interpreted on the basis of the formation of interconnecting continuous conducting networks.
The electromagnetic interference (EMI) shielding effectiveness of short carbon fibre-filled polyc... more The electromagnetic interference (EMI) shielding effectiveness of short carbon fibre-filled polychloroprene composites was studied in the frequency ranges 100 to 1000 MHz and 8 to 12 GHz. It was observed that, at a particular frequency, the shielding effectiveness increases with increasing loading of carbon fibre in the composite. Results show that 30 to 40 phr (parts per hundred parts of rubber) loading of fibre makes the rubber composite a potential EMI shielding material for use in the electronics industry.
Influence of Maleation of Ground Rubber Tyre (GRT) on the Thermorheological behaviour of Thermoplastic Elastomers Based on Ethylene Propylene Diene Rubber, GRT and Ethylene-co-acrylic acid
Polymers and Polymer Composites
The thermorheological behaviour of thermoplastic elastomeric blends based on both ground rubber t... more The thermorheological behaviour of thermoplastic elastomeric blends based on both ground rubber tyre (GRT) and maleic anhydride grafted GRT (m-GRT) has been studied. The blend composition based on m-GRT exhibits a higher melt viscosity than the corresponding control blend based on GRT. The former exhibits lower die swell and less melt fracture at low shear rates than the latter, when extruded at 180°C through a capillary rheometer. At high shear rates, however, both the blends exhibit melt fracture. There is apparently some interaction between m-GRT and the matrix, which is evident from dynamic mechanical analysis. The m-GRT causes a significant lowering in tanδ at temperatures higher than the Tg of the blend.
International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry
The mechanical properties and fracture mode of "Co y-ray irradiated blends of plasticized poly(vi... more The mechanical properties and fracture mode of "Co y-ray irradiated blends of plasticized poly(viny1 chloride) [PVC] and thermoplastic copolyester elastomer [Hytrel 4OD] have been investigated with specific reference to the effect of blend ratios and absorbed radiation doses. Samples were irradiated in the dose range of 0.1-50 Mrad in air at room temperature (25°C) at the rate of 0.321 Mrad/h. Hytrel and blends containing higher proportion of hytrel(2 50%) were found to undergo extensive crosslinking in the bulk which in effect caused a maximum in ultimate tensile strength at an absorbed dose of 1 Mrad, but showed a drastic drop in tensile strength at higher radiation doses (10-50 Mrad) due to embrittlement and surface oxidation. In the case of PVC and blends containing a higher proportion of PVC (2 75%) a slow decline in tensile strength was observed at lower radiation doses up to 10 Mrad, whereas at higher doses (10-50 Mrad), they showed a sharp decrease in tensile strength due to the degradation of the PVC phase. The elongation at break, tear strength and tensile set after failure of all the samples remain unchanged up to an absorbed dose of 1 Mrad but showed considerable reduction at higher radiation doses. The morphology of the irradiated surfaces after an absorbed dose of 50 Mrad has been examined by scanning electron microscope (SEM). SEM studies on the tensile and tear fracture surfaces also have been undertaken in order to gain an insight into the mechanism of failure.
Hydrogen-bonding interaction between alcohols and ethylene trithiocarbonate
The Journal of Physical Chemistry
... Mosk. Univ. Ser. 11, Khim., 17, No. 5, 14 (1962). (4) H. M. Rosenstock, JR Walton, and L. K. ... more ... Mosk. Univ. Ser. 11, Khim., 17, No. 5, 14 (1962). (4) H. M. Rosenstock, JR Walton, and L. K. Brice, US Atomic Energy Commission Report ORNL-2772 (1959). (5) G. Blue, JW Green, R. G. Bautista, and JL Margrave, J. Phys. Chem., 67, 877 (1963). ...
Thermally Induced Crosslinking in Blends of Poly(Vinyl Chloride) and Hydrogenated Acrylonitrile—Butadiene Rubber
Rubber Chemistry and Technology
A blend of Poly(vinyl chloride) (PVC) and hydrogenated acrylonitrile—butadiene rubber (HNBR) unde... more A blend of Poly(vinyl chloride) (PVC) and hydrogenated acrylonitrile—butadiene rubber (HNBR) undergoes crosslinking at high molding temperatures in the absence of any external curing agents. This is evident from Monsanto rheometric, solvent swelling, and infrared spectroscopic studies. The reaction proceeds through the interaction of allylic and tertiary chlorine in PVC, with amide and acid groups in HNBR formed during molding. The network structure is believed to consist of amide and ester crosslinks. Dynamic mechanical analysis and differential scanning calorimetry show that the blend components are miscible Variation in molding time and temperature has no effect on the miscibility.
Thermo-oxidative ageing and its effect on the network structure and fracture mode of natural rubber vulcanizates
Polymer
ABSTRACT
Studies on morphology, mechanical properties and failure mode of blends of plasticized poly(vinyl chloride) and thermoplastic copolyester elastomer
Journal of Vinyl and Additive Technology
Page 1. Studies on Morphology, Mechanical Properties and Failure Mode of Blends of Plasticized Po... more Page 1. Studies on Morphology, Mechanical Properties and Failure Mode of Blends of Plasticized Poly(Viny1 Chloride) and Thermoplastic Copolyester Elastomer SABU THOMAS, BR GUPTA, and SK DE Rubber Technology ...
Network structure of lignin-filled natural rubber vulcanizate
Journal of Polymer Science: Polymer Letters Edition
Dependence of Physical Properties and Processing Behavior of Blends of Silicone Rubber and Fluororubber on Blend Morphology
Rubber Chemistry and Technology
The paper reports that the processing behavior and physical properties of the blends of silicone ... more The paper reports that the processing behavior and physical properties of the blends of silicone rubber and fluororubber based on tetrafluoroethylene/propylene/vinylidene terpolymer. The processing behavior of the fluororubber can be improved on blending with low viscous silicone rubber. The results indicate that the processing behavior, mechanical properties, surface energies, and flammability of the blends are controlled by the blend morphology. Surface morphology of the blends show that blends of two rubbers are microheterogeneous and biphasic structure, wherein silicone rubber acts as a continuous matrix with the fluororubber as a dispersed phase.
Thermoplastic Elastomers Based on Waste Rubber and Plastics
Rubber Chemistry and Technology
This paper reviews the utilization of waste rubber and waste plastics for the preparation of ther... more This paper reviews the utilization of waste rubber and waste plastics for the preparation of thermoplastic elastomers (TPEs). TPEs based on ground rubber tire (GRT), waste EPDM rubber, waste nitrile rubber, recycled rubber, latex waste, and waste plastics are described with respect to composition and physical properties. It is found that part of the rubber phase or plastics phase or both in the rubber-plastics blend can be replaced with corresponding waste polymer for the preparation of thermoplastic elastomers. In many cases, the materials prepared from waste polymers show properties comparable to those prepared from fresh polymers. However, in some cases, the materials prepared from waste rubber or waste plastics cannot be classified as TPEs, as the blend compositions show very low elongation at break. Modification of the waste polymer or the use of compatibilizers result in stronger composites.
Short Jute Fiber Reinforced Rubber Composites
Rubber Chemistry and Technology
The following conclusions can be drawn from the above results and discussion: (1) The bonding bet... more The following conclusions can be drawn from the above results and discussion: (1) The bonding between jute fiber and rubber matrix is poor without any bonding agent. (2) Addition of 5 phr silica is essential and sufficient for promoting adhesion between fiber and matrix of a mix containing 5 phr resorcinol and 3.2 phr (3) The jute fiber will act as a reinforcing filler only when added above a volume loading of 10 percent. (4) The aging resistance of jute fiber reinforced natural rubber composites is excellent beyond a fiber loading of 10 volume percent.
N-H....pi. hydrogen bonding
The Journal of Physical Chemistry, 1971
Effect of silica filler on aluminum-aluminum bonding by a self-vulcanizable blend based on chlorobutyl rubber and carboxylated nitrile rubber
J Adhes Sci Technol, 1992
ABSTRACT
Self-Vulcanisable Rubber-Rubber Blends Based on Epoxidised Natural Rubber and Polychloroprene
Kautschuk Und Gummi Kunststoffe, 1991
Effect of cryo-ground rubber on melt flow and mechanical properties of polyprolylene
Polymer Engineering and Science, 1986
ABSTRACT
Surface chlorination of ground rubber tire and its characterization
Rubber Chemistry and Technology, Sep 1, 2001
Ground rubber tire (GRT) powders were chlorinated by trichloroisocyanuric acid (TCLCA). GRT powde... more Ground rubber tire (GRT) powders were chlorinated by trichloroisocyanuric acid (TCLCA). GRT powders of different chlorination levels were characterized by X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDAX), attenuated total reflection infrared (ATR-IR) spectroscopy, thermal, dielectric, and stress—strain properties on molded GRT specimens. Surface energy of the powders was estimated. Dynamic mechanical thermal analysis of molded GRT specimen reveals a biphasic structure. Plasticized poly(vinyl chloride) (PVC) compound, when blended with chlorinated GRT, shows improved physical properties in comparison to non-chlorinated GRT.
Journal of Applied Polymer Science, 1986
The effect of 6oCo y-radiation on the tensile properties of thermoplastic elastomer blends of nat... more The effect of 6oCo y-radiation on the tensile properties of thermoplastic elastomer blends of natural rubber (NR) and high-density polyethylene (HDPE) has been investigated. The samples were irradiated to absorbed doses ranging from 0.1 to 100 Mrad in air at room temperature (25°C) a t a dose rate of 0.21 Mrad/hr. The effect of blend ratio and addition of carbon black (N 330) dicumyl peroxide (DCP) on the radiation resistance of the blends has also been studied. High energy radiation at a high dose rate was found to cause extensive crosslinking in the bulk, which in effect, caused a minima in the ultimate tensile strength in the range of 10-25 Mrad and a continuous decline in the elongation a t break in all the blends. Chain scission, on the other hand, was restricted to the surface under the above-mentioned experimental conditions. This contention was substantiated by the results of irradiation of the samples in a nitrogen environment. Scanning electron microscopy @EM) studies on the tensile fracture surface morphology of the blends have also been undertaken in order to gain insight to the mechanism of failure.
Mixed Cross-Link Systems in Elastomers
Journal of Macromolecular Science Part C Polymer Reviews, Feb 23, 2007
ABSTRACT
Journal of Materials Science, 1990
The electrical conductivity of pressure-sensitive nitrile rubber composites, containing different... more The electrical conductivity of pressure-sensitive nitrile rubber composites, containing different Ioadings of particulate carbon black filler and short carbon fibre, have been studied. The conductivity of composites increases with increasing of filler concentration as well as with increased applied pressure up to a certain limit. The composites containing particulate fillers register low conductivity as compared to composites containing short carbon fibres, due to easy formation of an interconnecting network in the latter case. The effect of the orientation of short carbon fibre with respect to an applied electric field has also been studied. The pressure dependence of composites with transversely oriented carbon fibres with respect to electric fields is higher than that of composites with longitudinally oriented carbon fibres. The results are interpreted on the basis of the formation of interconnecting continuous conducting networks.
The electromagnetic interference (EMI) shielding effectiveness of short carbon fibre-filled polyc... more The electromagnetic interference (EMI) shielding effectiveness of short carbon fibre-filled polychloroprene composites was studied in the frequency ranges 100 to 1000 MHz and 8 to 12 GHz. It was observed that, at a particular frequency, the shielding effectiveness increases with increasing loading of carbon fibre in the composite. Results show that 30 to 40 phr (parts per hundred parts of rubber) loading of fibre makes the rubber composite a potential EMI shielding material for use in the electronics industry.
Influence of Maleation of Ground Rubber Tyre (GRT) on the Thermorheological behaviour of Thermoplastic Elastomers Based on Ethylene Propylene Diene Rubber, GRT and Ethylene-co-acrylic acid
Polymers and Polymer Composites
The thermorheological behaviour of thermoplastic elastomeric blends based on both ground rubber t... more The thermorheological behaviour of thermoplastic elastomeric blends based on both ground rubber tyre (GRT) and maleic anhydride grafted GRT (m-GRT) has been studied. The blend composition based on m-GRT exhibits a higher melt viscosity than the corresponding control blend based on GRT. The former exhibits lower die swell and less melt fracture at low shear rates than the latter, when extruded at 180°C through a capillary rheometer. At high shear rates, however, both the blends exhibit melt fracture. There is apparently some interaction between m-GRT and the matrix, which is evident from dynamic mechanical analysis. The m-GRT causes a significant lowering in tanδ at temperatures higher than the Tg of the blend.
International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry
The mechanical properties and fracture mode of "Co y-ray irradiated blends of plasticized poly(vi... more The mechanical properties and fracture mode of "Co y-ray irradiated blends of plasticized poly(viny1 chloride) [PVC] and thermoplastic copolyester elastomer [Hytrel 4OD] have been investigated with specific reference to the effect of blend ratios and absorbed radiation doses. Samples were irradiated in the dose range of 0.1-50 Mrad in air at room temperature (25°C) at the rate of 0.321 Mrad/h. Hytrel and blends containing higher proportion of hytrel(2 50%) were found to undergo extensive crosslinking in the bulk which in effect caused a maximum in ultimate tensile strength at an absorbed dose of 1 Mrad, but showed a drastic drop in tensile strength at higher radiation doses (10-50 Mrad) due to embrittlement and surface oxidation. In the case of PVC and blends containing a higher proportion of PVC (2 75%) a slow decline in tensile strength was observed at lower radiation doses up to 10 Mrad, whereas at higher doses (10-50 Mrad), they showed a sharp decrease in tensile strength due to the degradation of the PVC phase. The elongation at break, tear strength and tensile set after failure of all the samples remain unchanged up to an absorbed dose of 1 Mrad but showed considerable reduction at higher radiation doses. The morphology of the irradiated surfaces after an absorbed dose of 50 Mrad has been examined by scanning electron microscope (SEM). SEM studies on the tensile and tear fracture surfaces also have been undertaken in order to gain an insight into the mechanism of failure.
Hydrogen-bonding interaction between alcohols and ethylene trithiocarbonate
The Journal of Physical Chemistry
... Mosk. Univ. Ser. 11, Khim., 17, No. 5, 14 (1962). (4) H. M. Rosenstock, JR Walton, and L. K. ... more ... Mosk. Univ. Ser. 11, Khim., 17, No. 5, 14 (1962). (4) H. M. Rosenstock, JR Walton, and L. K. Brice, US Atomic Energy Commission Report ORNL-2772 (1959). (5) G. Blue, JW Green, R. G. Bautista, and JL Margrave, J. Phys. Chem., 67, 877 (1963). ...
Thermally Induced Crosslinking in Blends of Poly(Vinyl Chloride) and Hydrogenated Acrylonitrile—Butadiene Rubber
Rubber Chemistry and Technology
A blend of Poly(vinyl chloride) (PVC) and hydrogenated acrylonitrile—butadiene rubber (HNBR) unde... more A blend of Poly(vinyl chloride) (PVC) and hydrogenated acrylonitrile—butadiene rubber (HNBR) undergoes crosslinking at high molding temperatures in the absence of any external curing agents. This is evident from Monsanto rheometric, solvent swelling, and infrared spectroscopic studies. The reaction proceeds through the interaction of allylic and tertiary chlorine in PVC, with amide and acid groups in HNBR formed during molding. The network structure is believed to consist of amide and ester crosslinks. Dynamic mechanical analysis and differential scanning calorimetry show that the blend components are miscible Variation in molding time and temperature has no effect on the miscibility.
Thermo-oxidative ageing and its effect on the network structure and fracture mode of natural rubber vulcanizates
Polymer
ABSTRACT
Studies on morphology, mechanical properties and failure mode of blends of plasticized poly(vinyl chloride) and thermoplastic copolyester elastomer
Journal of Vinyl and Additive Technology
Page 1. Studies on Morphology, Mechanical Properties and Failure Mode of Blends of Plasticized Po... more Page 1. Studies on Morphology, Mechanical Properties and Failure Mode of Blends of Plasticized Poly(Viny1 Chloride) and Thermoplastic Copolyester Elastomer SABU THOMAS, BR GUPTA, and SK DE Rubber Technology ...
Network structure of lignin-filled natural rubber vulcanizate
Journal of Polymer Science: Polymer Letters Edition
Dependence of Physical Properties and Processing Behavior of Blends of Silicone Rubber and Fluororubber on Blend Morphology
Rubber Chemistry and Technology
The paper reports that the processing behavior and physical properties of the blends of silicone ... more The paper reports that the processing behavior and physical properties of the blends of silicone rubber and fluororubber based on tetrafluoroethylene/propylene/vinylidene terpolymer. The processing behavior of the fluororubber can be improved on blending with low viscous silicone rubber. The results indicate that the processing behavior, mechanical properties, surface energies, and flammability of the blends are controlled by the blend morphology. Surface morphology of the blends show that blends of two rubbers are microheterogeneous and biphasic structure, wherein silicone rubber acts as a continuous matrix with the fluororubber as a dispersed phase.
Thermoplastic Elastomers Based on Waste Rubber and Plastics
Rubber Chemistry and Technology
This paper reviews the utilization of waste rubber and waste plastics for the preparation of ther... more This paper reviews the utilization of waste rubber and waste plastics for the preparation of thermoplastic elastomers (TPEs). TPEs based on ground rubber tire (GRT), waste EPDM rubber, waste nitrile rubber, recycled rubber, latex waste, and waste plastics are described with respect to composition and physical properties. It is found that part of the rubber phase or plastics phase or both in the rubber-plastics blend can be replaced with corresponding waste polymer for the preparation of thermoplastic elastomers. In many cases, the materials prepared from waste polymers show properties comparable to those prepared from fresh polymers. However, in some cases, the materials prepared from waste rubber or waste plastics cannot be classified as TPEs, as the blend compositions show very low elongation at break. Modification of the waste polymer or the use of compatibilizers result in stronger composites.
Short Jute Fiber Reinforced Rubber Composites
Rubber Chemistry and Technology
The following conclusions can be drawn from the above results and discussion: (1) The bonding bet... more The following conclusions can be drawn from the above results and discussion: (1) The bonding between jute fiber and rubber matrix is poor without any bonding agent. (2) Addition of 5 phr silica is essential and sufficient for promoting adhesion between fiber and matrix of a mix containing 5 phr resorcinol and 3.2 phr (3) The jute fiber will act as a reinforcing filler only when added above a volume loading of 10 percent. (4) The aging resistance of jute fiber reinforced natural rubber composites is excellent beyond a fiber loading of 10 volume percent.
N-H....pi. hydrogen bonding
The Journal of Physical Chemistry, 1971
Effect of silica filler on aluminum-aluminum bonding by a self-vulcanizable blend based on chlorobutyl rubber and carboxylated nitrile rubber
J Adhes Sci Technol, 1992
ABSTRACT
Self-Vulcanisable Rubber-Rubber Blends Based on Epoxidised Natural Rubber and Polychloroprene
Kautschuk Und Gummi Kunststoffe, 1991
Effect of cryo-ground rubber on melt flow and mechanical properties of polyprolylene
Polymer Engineering and Science, 1986
ABSTRACT
Surface chlorination of ground rubber tire and its characterization
Rubber Chemistry and Technology, Sep 1, 2001
Ground rubber tire (GRT) powders were chlorinated by trichloroisocyanuric acid (TCLCA). GRT powde... more Ground rubber tire (GRT) powders were chlorinated by trichloroisocyanuric acid (TCLCA). GRT powders of different chlorination levels were characterized by X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDAX), attenuated total reflection infrared (ATR-IR) spectroscopy, thermal, dielectric, and stress—strain properties on molded GRT specimens. Surface energy of the powders was estimated. Dynamic mechanical thermal analysis of molded GRT specimen reveals a biphasic structure. Plasticized poly(vinyl chloride) (PVC) compound, when blended with chlorinated GRT, shows improved physical properties in comparison to non-chlorinated GRT.
Journal of Applied Polymer Science, 1986
The effect of 6oCo y-radiation on the tensile properties of thermoplastic elastomer blends of nat... more The effect of 6oCo y-radiation on the tensile properties of thermoplastic elastomer blends of natural rubber (NR) and high-density polyethylene (HDPE) has been investigated. The samples were irradiated to absorbed doses ranging from 0.1 to 100 Mrad in air at room temperature (25°C) a t a dose rate of 0.21 Mrad/hr. The effect of blend ratio and addition of carbon black (N 330) dicumyl peroxide (DCP) on the radiation resistance of the blends has also been studied. High energy radiation at a high dose rate was found to cause extensive crosslinking in the bulk, which in effect, caused a minima in the ultimate tensile strength in the range of 10-25 Mrad and a continuous decline in the elongation a t break in all the blends. Chain scission, on the other hand, was restricted to the surface under the above-mentioned experimental conditions. This contention was substantiated by the results of irradiation of the samples in a nitrogen environment. Scanning electron microscopy @EM) studies on the tensile fracture surface morphology of the blends have also been undertaken in order to gain insight to the mechanism of failure.
Mixed Cross-Link Systems in Elastomers
Journal of Macromolecular Science Part C Polymer Reviews, Feb 23, 2007
ABSTRACT