ABSTRACT The nanocomposite of 50/50 acrylonitrile styrene acrylate/Zn-ionomer blend uses varying ... more ABSTRACT The nanocomposite of 50/50 acrylonitrile styrene acrylate/Zn-ionomer blend uses varying weight ratios (0.5–5.0%) of multiwalled carbon nanotubes. The morphological, thermal, thermomechanical, and creep behavior along with metal adhesion were evaluated. The phase-separated surface morphology of the blend formed non-uniform microscale nanotube dispersion and resulted in nanotube network formation at 1 wt%. Lowest creep compliance and increased complex modulus were found at 1 wt% nanotube loading. The presence of weather resistant acrylonitrile styrene acrylate and carbon nanotubes made the nanocomposite excellent weather resistant. GRAPHICAL ABSTRACT
The mucilaginous polysaccharide from Abroma augusta stem was examined for its physicochemical, th... more The mucilaginous polysaccharide from Abroma augusta stem was examined for its physicochemical, thermal, and functional behavior and explored as a carrier for probiotic bacteria. Composed of glucose, galactose, rhamnose, galactouronic acid and fucose, Abroma augusta mucilage (AAM) exhibited shear thinning behavior (following power law equation) and gel like characteristic (showing higher G' value than G″ value). AAM promoted the growth of probiotic strains with positive prebiotic scores of 0.5 ± 0.06 and 0.51 ± 0.05 for Lactobacillus acidophilus and Lactobacillus casei, respectively. Further, probiotic strains were embedded in the AAM matrix followed by freeze-drying with embedding efficiency of >95%. Viscoelastic properties were retained substantially in the rehydrated probiotic-embedded matrix. AAM could protect probiotic bacteria in simulated gastrointestinal conditions, at elevated (80 °C, 20 min) and at low (4 °C, 4 months) temperatures ensuring higher viabilities of embedded probiotic cells. Our findings established potential carrier capabilities of AAM polysaccharides for probiotic bacteria with thickening and prebiotic activity.
Proton exchange membrane (PEM) fuel cells are one of the most emerging alternative energy technol... more Proton exchange membrane (PEM) fuel cells are one of the most emerging alternative energy technologies under development. A novel proton exchange membrane sulfonated polyethersulfone (SPES) was developed by homogeneous method using phthalic anhydride as catalyst and chlorosulfonic acid as sulfonating agent to control the sulfonation reaction. The method of sulfonation was optimized by varying the reaction time and concentration of the catalyst. The structure of the SPES was studied by 1 H-Nuclear Magnetic Resonance, Fourier Transform Infra Red Spectroscopy and X-ray diffraction. The extent of sulfonation was determined by ion exchange capacity studies. The thermal and mechanical stabilities were studied using thermogravimetric analysis (TGA) and Dynamic Mechanical Analysis (DMA) respectively. DMA results show that the storage modulus increased with increase in degree of sulfonation (DS) and water uptake of SPES increased with DS. The proton conductivity of SPES (34% DS) measured by ...
Progress in Rubber, Plastics and Recycling Technology, 2009
A surface-modifi ed carbon black (N330) has been prepared by treating it with pentaerythitol, com... more A surface-modifi ed carbon black (N330) has been prepared by treating it with pentaerythitol, combination of pentaerythitol and pyrogallol and a combination of pentaerythitol and resorcinol in aqueous solution at different molar concentrations. The adsorption of modifi er and formation of new functional groups could be identifi ed from the FTIR peaks. This modifi ed carbon black has been used as one of the compounding ingredients in EPDM rubber. It was found that carbon black modifi ed with pentaerythitol and resorcinol showed more pronounced effect than the other two. In all cases the properties like hardness, tensile strength, and modulus are found to be increasing as the concentration of modifi er was increased. All these values are higher as compared to rubber compound with unmodifi ed carbon black. While the properties like abrasion loss, compression set, elongation at break, tan delta were found to be decreasing with increase in modifi er concentration. All these results points towards an improved interaction between the fi ller and rubber. The surface functional groups on the modifi ed carbon black would attach to the rubber chains and will act as secondary cross linker. Calculated values of crosslink density were found to be increasing with the modifi er concentrations, clearly defi nes the formation of secondary crosslinking.
Due to the graded micro-structure and high specific strength-stiffness, bamboo micro fillers are ... more Due to the graded micro-structure and high specific strength-stiffness, bamboo micro fillers are systematically utilized in reinforcing different thermoset and thermoplastic polymers as replacement of conventional glass and carbon fillers. In this work, micro-size bamboo particle fillers are reinforced in 'specific grade' thermoset epoxy matrix and its fracture properties has been evaluated by following linear elastic fracture mechanics. To enhance its compatibility with the polymer matrix and to reduce the hydrophilicity, the bamboo micro fillers are surface modified through alkaline treatment. The extent of surface modification and removal of lower weight polymers from filler surface are examined and established by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction analysis and thermogravimetric analysis. The fracture properties of bamboo-epoxy composite material are observed to be increasing with the addition of bamboo fillers and the maximum value of fracture toughness is 0.678 MPa.m 0.5 which is 32% higher than the same for neat epoxy samples. In addition, the mechanisms of notch initiated fracture propagation have also been explained for the understanding of stress singularity present at the preexisted crack tip.
Recently, natural fiber based composites have received widespread attention due to their applicat... more Recently, natural fiber based composites have received widespread attention due to their application in car bodies, sporting goods, building panels, industrial, and other commercial markets. In the present study, various chemical treatments of native luffa fiber (Luffa cylindrica) surfaces using alkalization (2 h agitation with 5 % KOH) and furfurylation (graft furfuryl alcohol followed by oxidation with K2Cr2O7 (1N) is discussed and compared. The purpose of chemical treatments is to improve the fiber-matrix compatibility, interfacial strength, physical, mechanical and thermal properties, etc. The grafting of furfuryl alcohol followed by oxidation-generated quinines showed better results than alkaline treatments with respect to enhancement of surface area, compatibility and hydrophobicity together with removal of waxes, lignin and hemicelluloses. The treated surface was characterized by ultraviolet-visible spectroscopy and dynamic contact angle measurements. DSC, TGA, SEM, water absorption and mechanical tests were performed to determine the thermal, morphological and mechanical properties of untreated and chemically treated luffa fiber.
Purpose The purpose of this paper is to study the effect of various stoichiometric ratios for syn... more Purpose The purpose of this paper is to study the effect of various stoichiometric ratios for synthesised epoxy phenolic novolac (EPN) resins on their physicochemical, thermomechanical and morphological properties. Design/methodology/approach In the present study, EPN (EPN-1, EPN-2, EPN-3, EPN-4 and EPN-5) resins were synthesised by varying five types of different stoichiometric ratios for phenol/formaldehyde along with the corresponding molar ratios for novolac/epichlorohydrin. Their different physicochemical properties of interest, thermomechanical properties as well as morphological properties were studied by means of cured samples with the variation of its stoichiometric ratios. Findings The average functionality and reactivity of EPN resin can be controlled by controlling epoxy equivalence as well as cross-linking density upon its curing as all of these factors are internally correlated with each other. Research limitations/implications Epoxy resins are characterised by a three...
Abstract In this study an attempt was made to develop a low cost composite, abundantly available ... more Abstract In this study an attempt was made to develop a low cost composite, abundantly available kaolin was reinforced with epoxy matrix in six different percentage of filler weight by compression moulding technique, those weight percentage are 0%, 1.5%, 3%, 4.5%, 6% and 7.5%. Processed samples of kaolin reinforced epoxy were tested for their strength by tensile testing and flexural testing at three different crosshead speeds of 3 mm/min, 5 mm/min and 7 mm/min. tensile and flexural tests were performed taking gauge length 50 mm and dimensions recommended by ASTM. These experiment were conducted according to taguchi L18 orthogonal array mixed level design taking two factors filler content and speed of testing, six and three independent levels were assigned for aforesaid factors. The experimental results were analyzed by taguchi optimization method for finding out optimum values of strength in tensile tests and flexural tests independently. Signal to noise ratio (S/N) were obtained for analysis of variance (ANOVA) analysis to signify the dominating factors which affects strength. This analysis showed that filler content was key factor that effect strength significantly at 95% confidence level. Confirmation tests were also performed to validate the analysis and it was found that there was improvement in S/N ratios of both tensile and flexural strength.
The effect of variable amount of multiwalled carbon nanotubes on mechanical, rheological, and ele... more The effect of variable amount of multiwalled carbon nanotubes on mechanical, rheological, and electrical properties of acrylonitrile–styrene–acrylate/Zn+2-poly(ethylene-co-methacrylic acid) ionomer blend system has been evaluated. Optical micrographs as well as alternating current conductivity data shows the formation of nanotube percolation network at 1 wt% nanotube content. The polymer/nanotube interaction increased the rate of tensile modulus to 55 GPa at low nanotube content. The polymer chain relaxation time was increased upto 1 wt% of nanotube content, but higher nanotube loading reduced the time. The zero-shear viscosity was function of nanotube content whereas the infinite-shear viscosity was independent of nanotube content. GRAPHICAL ABSTRACT
Purpose-The purpose of this paper is to improve the properties of shellac by blending with novola... more Purpose-The purpose of this paper is to improve the properties of shellac by blending with novolac and to study the thermal behaviour of the blends with an ultimate aim to use as surface coating material. Design/methodology/approach-Novolac was synthesized by reaction of phenol with formaldehyde in a molar ratio of 1:0.8, in acidic condition. Blending of shellac with novolac was done in solution and films of the blends, prepared on glass slides and tin panels, were baked at 1508C for 15 minutes. Properties of the films were studied as per standard procedures. Findings-Films of shellac-novolac blends showed improvement in gloss and impact resistance compared to those of shellac alone. Gloss of blends increased with the increase in concentration of novolac and further increased on baking the films. Scratch hardness of shellac decreased on blending with novolac. Baked films of the blends showed resistance to heat and water. Films of shellac-novolac blends were found to be more resistant to polar solvents compared to non-polar solvents. Research limitations/implications-Shellac, prepared from kusmi seedlac, was used in the study. Besides shellac, dewaxed decolorized lac (DDL), dewaxed lac (DL) and bleached lac (BL) could also be used for study on blending with novolac. Practical implications-Blending of shellac with novolac improved the film properties of shellac. The study suggests that the compositions can be utilised in developing formulations of coating material with improved properties for metal surfaces. Originality/value-The formulations based on modification of shellac with novolac and study of the film properties utilising various instruments are novel. The formulations based on shellac and novolac can find applications in the field of surface coating with desired purposes.
Purpose-The purpose of this paper is to see the effect in the properties of shellac on blending w... more Purpose-The purpose of this paper is to see the effect in the properties of shellac on blending with rosin (another natural resin) and study their changes during storage. Design/methodology/approach-Blending of rosin was done at seedlac (semi-pure lac) stage. Shellac was then prepared by bhatta (Indian country) process, in the form of button lac. Physico-chemical properties of the blends were studied at regular time intervals following standard procedures. Findings-Improvement in the physicochemical properties of shellac was noticed by blending with rosin to a great extent; less degradation in the properties of blends was observed with storage compared to those of parent shellac. Research limitations/implications-Because rosin possesses very high fluidity and life under heat, exact value of flow and life under heat of rosin and its blends with shellac having high rosin content could not be determined. Practical implications-The results give an idea to entrepreneurs, processors and industrialists of how much rosin is to be blended with shellac to bring improvements in its fluidity and life under heat for commercial exploitation, especially for inferior quality of shellac. Originality/value-Systematic study has been done for the first time, as no quantitative data was available on the changes in the different properties of shellac which take place on blending with rosin.
ABSTRACT A new class of blend system comprising weather resistant acrylonitrile/styrene/acrylate ... more ABSTRACT A new class of blend system comprising weather resistant acrylonitrile/styrene/acrylate (ASA) terpolymer and Zn-ionomer was developed. Based on Zn-ionomer content, the blend system either forms ‘mushroom’ or ‘brush’ type conformation which affected dynamic rheology, DSC, DMA and creep properties differently. Formation of ionic crosslinkings by Zn-ionomer in ‘brush regime’ as well as limited ionic crosslinkings in ‘mushroom regime’ resulted in different nature molecular chain relaxation response. The DSC endotherm peak and glass transition temperature were also influenced by the type of conformation and ion-dipole interaction between the blend components. The tan δ from DMA study also reflected the similar trend. The creep deformation behavior of the blend was found to be dependent on highly deformable Zn-ionomer content and with temperature. The Findley model analysis suggests the ionic crosslinkings may be the possible reason for controlled creep deformation of the blend.
Acrylonitrile-styrene-acrylic (ASA) terpolymer was blended with a sodium neutralized poly (ethyle... more Acrylonitrile-styrene-acrylic (ASA) terpolymer was blended with a sodium neutralized poly (ethylene-comethacrylic acid) ionomer to develop a weather-resistant ASA with good heat sealing and adhesion properties. Both tensile strengths and modulus were reduced by about 45% with an increase in Na-ionomer concentration of 50%. The mechanical data were fitted with different models that predict mechanical behavior. The thermal stability was increased with the incorporation of ionomer. The temperature corresponding to 50% mass loss (T m50) was increased from 400 C (for ASA) to 427 C for 50/50 ASA/Na-ionomer blend. SEM and AFM micrographs reveal the cone-shaped microstructure on the ASA matrix surface after a critical Na-ionomer concentration of 30%. This blend system follows typical non-Newtonian behavior. The heat sealing performance study with metal was also carried out to investigate the utilization of these blend systems as a protective layer for metal. POLYM.
ABSTRACT The present study deals with acrylonitrile–styrene–acrylic elastomer (ASA) terpolymer an... more ABSTRACT The present study deals with acrylonitrile–styrene–acrylic elastomer (ASA) terpolymer and an ionomer based blend to develop a weather resistant material with good heat sealability and excellent adhesion properties. The mechanical properties of ASA/ionomer blends were reduced with increase in ionomer content, whereas the thermal stability was improved. On addition of ionomer, the effects of shear rate and temperature on melt viscosity were also investigated. The mechanical modulli were also carried out to justify and correlate with ionomer content. The thermal stability, investigated by thermogravimetric analysis, showed that the thermal stability was increased with the incorporation of ionomer.
The effect of organoclay Cloisite Ò 20A and controlled peroxide curing on the dielectric properti... more The effect of organoclay Cloisite Ò 20A and controlled peroxide curing on the dielectric properties and flammability of LLDPE/EMA blend is explored in this article. The organoclay Cloisite Ò 20A were melt blended with the LLDPE/EMA system at 1, 3, 5, and 7 wt% loading through the variation of the sequence of addition. The dielectric properties of the blend composites are evaluated at different temperature and frequency ranges. Results obtained reveal that the dielectric properties of LLDPE/EMA blend is influenced remarkably by extent of clay loading, variation of sequence of addition of organoclay, and controlled peroxide curing. Both the frequency and temperature dependency of dielectric constant is higher for filled samples than for control blend. On peroxide curing, dielectric constant decreases for all samples and is more significant in case of filled samples. The volume resistivity and breakdown voltage of the samples have also been evaluated. Limiting oxygen index of LLDPE/EMA blends is moderately improved on addition of organoclay.
ABSTRACT The nanocomposite of 50/50 acrylonitrile styrene acrylate/Zn-ionomer blend uses varying ... more ABSTRACT The nanocomposite of 50/50 acrylonitrile styrene acrylate/Zn-ionomer blend uses varying weight ratios (0.5–5.0%) of multiwalled carbon nanotubes. The morphological, thermal, thermomechanical, and creep behavior along with metal adhesion were evaluated. The phase-separated surface morphology of the blend formed non-uniform microscale nanotube dispersion and resulted in nanotube network formation at 1 wt%. Lowest creep compliance and increased complex modulus were found at 1 wt% nanotube loading. The presence of weather resistant acrylonitrile styrene acrylate and carbon nanotubes made the nanocomposite excellent weather resistant. GRAPHICAL ABSTRACT
The mucilaginous polysaccharide from Abroma augusta stem was examined for its physicochemical, th... more The mucilaginous polysaccharide from Abroma augusta stem was examined for its physicochemical, thermal, and functional behavior and explored as a carrier for probiotic bacteria. Composed of glucose, galactose, rhamnose, galactouronic acid and fucose, Abroma augusta mucilage (AAM) exhibited shear thinning behavior (following power law equation) and gel like characteristic (showing higher G' value than G″ value). AAM promoted the growth of probiotic strains with positive prebiotic scores of 0.5 ± 0.06 and 0.51 ± 0.05 for Lactobacillus acidophilus and Lactobacillus casei, respectively. Further, probiotic strains were embedded in the AAM matrix followed by freeze-drying with embedding efficiency of >95%. Viscoelastic properties were retained substantially in the rehydrated probiotic-embedded matrix. AAM could protect probiotic bacteria in simulated gastrointestinal conditions, at elevated (80 °C, 20 min) and at low (4 °C, 4 months) temperatures ensuring higher viabilities of embedded probiotic cells. Our findings established potential carrier capabilities of AAM polysaccharides for probiotic bacteria with thickening and prebiotic activity.
Proton exchange membrane (PEM) fuel cells are one of the most emerging alternative energy technol... more Proton exchange membrane (PEM) fuel cells are one of the most emerging alternative energy technologies under development. A novel proton exchange membrane sulfonated polyethersulfone (SPES) was developed by homogeneous method using phthalic anhydride as catalyst and chlorosulfonic acid as sulfonating agent to control the sulfonation reaction. The method of sulfonation was optimized by varying the reaction time and concentration of the catalyst. The structure of the SPES was studied by 1 H-Nuclear Magnetic Resonance, Fourier Transform Infra Red Spectroscopy and X-ray diffraction. The extent of sulfonation was determined by ion exchange capacity studies. The thermal and mechanical stabilities were studied using thermogravimetric analysis (TGA) and Dynamic Mechanical Analysis (DMA) respectively. DMA results show that the storage modulus increased with increase in degree of sulfonation (DS) and water uptake of SPES increased with DS. The proton conductivity of SPES (34% DS) measured by ...
Progress in Rubber, Plastics and Recycling Technology, 2009
A surface-modifi ed carbon black (N330) has been prepared by treating it with pentaerythitol, com... more A surface-modifi ed carbon black (N330) has been prepared by treating it with pentaerythitol, combination of pentaerythitol and pyrogallol and a combination of pentaerythitol and resorcinol in aqueous solution at different molar concentrations. The adsorption of modifi er and formation of new functional groups could be identifi ed from the FTIR peaks. This modifi ed carbon black has been used as one of the compounding ingredients in EPDM rubber. It was found that carbon black modifi ed with pentaerythitol and resorcinol showed more pronounced effect than the other two. In all cases the properties like hardness, tensile strength, and modulus are found to be increasing as the concentration of modifi er was increased. All these values are higher as compared to rubber compound with unmodifi ed carbon black. While the properties like abrasion loss, compression set, elongation at break, tan delta were found to be decreasing with increase in modifi er concentration. All these results points towards an improved interaction between the fi ller and rubber. The surface functional groups on the modifi ed carbon black would attach to the rubber chains and will act as secondary cross linker. Calculated values of crosslink density were found to be increasing with the modifi er concentrations, clearly defi nes the formation of secondary crosslinking.
Due to the graded micro-structure and high specific strength-stiffness, bamboo micro fillers are ... more Due to the graded micro-structure and high specific strength-stiffness, bamboo micro fillers are systematically utilized in reinforcing different thermoset and thermoplastic polymers as replacement of conventional glass and carbon fillers. In this work, micro-size bamboo particle fillers are reinforced in 'specific grade' thermoset epoxy matrix and its fracture properties has been evaluated by following linear elastic fracture mechanics. To enhance its compatibility with the polymer matrix and to reduce the hydrophilicity, the bamboo micro fillers are surface modified through alkaline treatment. The extent of surface modification and removal of lower weight polymers from filler surface are examined and established by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction analysis and thermogravimetric analysis. The fracture properties of bamboo-epoxy composite material are observed to be increasing with the addition of bamboo fillers and the maximum value of fracture toughness is 0.678 MPa.m 0.5 which is 32% higher than the same for neat epoxy samples. In addition, the mechanisms of notch initiated fracture propagation have also been explained for the understanding of stress singularity present at the preexisted crack tip.
Recently, natural fiber based composites have received widespread attention due to their applicat... more Recently, natural fiber based composites have received widespread attention due to their application in car bodies, sporting goods, building panels, industrial, and other commercial markets. In the present study, various chemical treatments of native luffa fiber (Luffa cylindrica) surfaces using alkalization (2 h agitation with 5 % KOH) and furfurylation (graft furfuryl alcohol followed by oxidation with K2Cr2O7 (1N) is discussed and compared. The purpose of chemical treatments is to improve the fiber-matrix compatibility, interfacial strength, physical, mechanical and thermal properties, etc. The grafting of furfuryl alcohol followed by oxidation-generated quinines showed better results than alkaline treatments with respect to enhancement of surface area, compatibility and hydrophobicity together with removal of waxes, lignin and hemicelluloses. The treated surface was characterized by ultraviolet-visible spectroscopy and dynamic contact angle measurements. DSC, TGA, SEM, water absorption and mechanical tests were performed to determine the thermal, morphological and mechanical properties of untreated and chemically treated luffa fiber.
Purpose The purpose of this paper is to study the effect of various stoichiometric ratios for syn... more Purpose The purpose of this paper is to study the effect of various stoichiometric ratios for synthesised epoxy phenolic novolac (EPN) resins on their physicochemical, thermomechanical and morphological properties. Design/methodology/approach In the present study, EPN (EPN-1, EPN-2, EPN-3, EPN-4 and EPN-5) resins were synthesised by varying five types of different stoichiometric ratios for phenol/formaldehyde along with the corresponding molar ratios for novolac/epichlorohydrin. Their different physicochemical properties of interest, thermomechanical properties as well as morphological properties were studied by means of cured samples with the variation of its stoichiometric ratios. Findings The average functionality and reactivity of EPN resin can be controlled by controlling epoxy equivalence as well as cross-linking density upon its curing as all of these factors are internally correlated with each other. Research limitations/implications Epoxy resins are characterised by a three...
Abstract In this study an attempt was made to develop a low cost composite, abundantly available ... more Abstract In this study an attempt was made to develop a low cost composite, abundantly available kaolin was reinforced with epoxy matrix in six different percentage of filler weight by compression moulding technique, those weight percentage are 0%, 1.5%, 3%, 4.5%, 6% and 7.5%. Processed samples of kaolin reinforced epoxy were tested for their strength by tensile testing and flexural testing at three different crosshead speeds of 3 mm/min, 5 mm/min and 7 mm/min. tensile and flexural tests were performed taking gauge length 50 mm and dimensions recommended by ASTM. These experiment were conducted according to taguchi L18 orthogonal array mixed level design taking two factors filler content and speed of testing, six and three independent levels were assigned for aforesaid factors. The experimental results were analyzed by taguchi optimization method for finding out optimum values of strength in tensile tests and flexural tests independently. Signal to noise ratio (S/N) were obtained for analysis of variance (ANOVA) analysis to signify the dominating factors which affects strength. This analysis showed that filler content was key factor that effect strength significantly at 95% confidence level. Confirmation tests were also performed to validate the analysis and it was found that there was improvement in S/N ratios of both tensile and flexural strength.
The effect of variable amount of multiwalled carbon nanotubes on mechanical, rheological, and ele... more The effect of variable amount of multiwalled carbon nanotubes on mechanical, rheological, and electrical properties of acrylonitrile–styrene–acrylate/Zn+2-poly(ethylene-co-methacrylic acid) ionomer blend system has been evaluated. Optical micrographs as well as alternating current conductivity data shows the formation of nanotube percolation network at 1 wt% nanotube content. The polymer/nanotube interaction increased the rate of tensile modulus to 55 GPa at low nanotube content. The polymer chain relaxation time was increased upto 1 wt% of nanotube content, but higher nanotube loading reduced the time. The zero-shear viscosity was function of nanotube content whereas the infinite-shear viscosity was independent of nanotube content. GRAPHICAL ABSTRACT
Purpose-The purpose of this paper is to improve the properties of shellac by blending with novola... more Purpose-The purpose of this paper is to improve the properties of shellac by blending with novolac and to study the thermal behaviour of the blends with an ultimate aim to use as surface coating material. Design/methodology/approach-Novolac was synthesized by reaction of phenol with formaldehyde in a molar ratio of 1:0.8, in acidic condition. Blending of shellac with novolac was done in solution and films of the blends, prepared on glass slides and tin panels, were baked at 1508C for 15 minutes. Properties of the films were studied as per standard procedures. Findings-Films of shellac-novolac blends showed improvement in gloss and impact resistance compared to those of shellac alone. Gloss of blends increased with the increase in concentration of novolac and further increased on baking the films. Scratch hardness of shellac decreased on blending with novolac. Baked films of the blends showed resistance to heat and water. Films of shellac-novolac blends were found to be more resistant to polar solvents compared to non-polar solvents. Research limitations/implications-Shellac, prepared from kusmi seedlac, was used in the study. Besides shellac, dewaxed decolorized lac (DDL), dewaxed lac (DL) and bleached lac (BL) could also be used for study on blending with novolac. Practical implications-Blending of shellac with novolac improved the film properties of shellac. The study suggests that the compositions can be utilised in developing formulations of coating material with improved properties for metal surfaces. Originality/value-The formulations based on modification of shellac with novolac and study of the film properties utilising various instruments are novel. The formulations based on shellac and novolac can find applications in the field of surface coating with desired purposes.
Purpose-The purpose of this paper is to see the effect in the properties of shellac on blending w... more Purpose-The purpose of this paper is to see the effect in the properties of shellac on blending with rosin (another natural resin) and study their changes during storage. Design/methodology/approach-Blending of rosin was done at seedlac (semi-pure lac) stage. Shellac was then prepared by bhatta (Indian country) process, in the form of button lac. Physico-chemical properties of the blends were studied at regular time intervals following standard procedures. Findings-Improvement in the physicochemical properties of shellac was noticed by blending with rosin to a great extent; less degradation in the properties of blends was observed with storage compared to those of parent shellac. Research limitations/implications-Because rosin possesses very high fluidity and life under heat, exact value of flow and life under heat of rosin and its blends with shellac having high rosin content could not be determined. Practical implications-The results give an idea to entrepreneurs, processors and industrialists of how much rosin is to be blended with shellac to bring improvements in its fluidity and life under heat for commercial exploitation, especially for inferior quality of shellac. Originality/value-Systematic study has been done for the first time, as no quantitative data was available on the changes in the different properties of shellac which take place on blending with rosin.
ABSTRACT A new class of blend system comprising weather resistant acrylonitrile/styrene/acrylate ... more ABSTRACT A new class of blend system comprising weather resistant acrylonitrile/styrene/acrylate (ASA) terpolymer and Zn-ionomer was developed. Based on Zn-ionomer content, the blend system either forms ‘mushroom’ or ‘brush’ type conformation which affected dynamic rheology, DSC, DMA and creep properties differently. Formation of ionic crosslinkings by Zn-ionomer in ‘brush regime’ as well as limited ionic crosslinkings in ‘mushroom regime’ resulted in different nature molecular chain relaxation response. The DSC endotherm peak and glass transition temperature were also influenced by the type of conformation and ion-dipole interaction between the blend components. The tan δ from DMA study also reflected the similar trend. The creep deformation behavior of the blend was found to be dependent on highly deformable Zn-ionomer content and with temperature. The Findley model analysis suggests the ionic crosslinkings may be the possible reason for controlled creep deformation of the blend.
Acrylonitrile-styrene-acrylic (ASA) terpolymer was blended with a sodium neutralized poly (ethyle... more Acrylonitrile-styrene-acrylic (ASA) terpolymer was blended with a sodium neutralized poly (ethylene-comethacrylic acid) ionomer to develop a weather-resistant ASA with good heat sealing and adhesion properties. Both tensile strengths and modulus were reduced by about 45% with an increase in Na-ionomer concentration of 50%. The mechanical data were fitted with different models that predict mechanical behavior. The thermal stability was increased with the incorporation of ionomer. The temperature corresponding to 50% mass loss (T m50) was increased from 400 C (for ASA) to 427 C for 50/50 ASA/Na-ionomer blend. SEM and AFM micrographs reveal the cone-shaped microstructure on the ASA matrix surface after a critical Na-ionomer concentration of 30%. This blend system follows typical non-Newtonian behavior. The heat sealing performance study with metal was also carried out to investigate the utilization of these blend systems as a protective layer for metal. POLYM.
ABSTRACT The present study deals with acrylonitrile–styrene–acrylic elastomer (ASA) terpolymer an... more ABSTRACT The present study deals with acrylonitrile–styrene–acrylic elastomer (ASA) terpolymer and an ionomer based blend to develop a weather resistant material with good heat sealability and excellent adhesion properties. The mechanical properties of ASA/ionomer blends were reduced with increase in ionomer content, whereas the thermal stability was improved. On addition of ionomer, the effects of shear rate and temperature on melt viscosity were also investigated. The mechanical modulli were also carried out to justify and correlate with ionomer content. The thermal stability, investigated by thermogravimetric analysis, showed that the thermal stability was increased with the incorporation of ionomer.
The effect of organoclay Cloisite Ò 20A and controlled peroxide curing on the dielectric properti... more The effect of organoclay Cloisite Ò 20A and controlled peroxide curing on the dielectric properties and flammability of LLDPE/EMA blend is explored in this article. The organoclay Cloisite Ò 20A were melt blended with the LLDPE/EMA system at 1, 3, 5, and 7 wt% loading through the variation of the sequence of addition. The dielectric properties of the blend composites are evaluated at different temperature and frequency ranges. Results obtained reveal that the dielectric properties of LLDPE/EMA blend is influenced remarkably by extent of clay loading, variation of sequence of addition of organoclay, and controlled peroxide curing. Both the frequency and temperature dependency of dielectric constant is higher for filled samples than for control blend. On peroxide curing, dielectric constant decreases for all samples and is more significant in case of filled samples. The volume resistivity and breakdown voltage of the samples have also been evaluated. Limiting oxygen index of LLDPE/EMA blends is moderately improved on addition of organoclay.
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Papers by Gautam Sarkhel