Abstract: | This 'study' deals with a preliminary study of automatic beam steering properly in conducting polyaniline . Polyaniline in its undoped and doped .state was prepared from aniline by the chemical oxidative polymerization method. Dielectric properties of the samples were studied at S-band microwave frequencies using cavity perturbation technique. It is found that undoped po/vanihne is having greater dielectric loss and conductivity contpared with the doped samples. The beam steering property is studied using a perspex rod antenna and HP 85/OC vector network analyzer. The shift in the radiated beam is studied for different do voltages. The results show that polyaniline is a good nutterial far beam steering applications. |
URI: | http://dyuthi.cusat.ac.in/purl/809 |
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Rajesh Menon an ... iline as an...July2007.PDF | (3.204Mb) |
Abstract: | Polymer-solvent interaction parameters for the blends of natural rubber (NR) with styrene-butadiene rubber (SBR) and polybutadiene rubber ( BR) are calculated using the Flory-Rehner equation by equating the network density of the vulcanizates in two solvents. |
URI: | http://dyuthi.cusat.ac.in/purl/834 |
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Rani Joseph an ... ymer solvent..,Nov1986.PDF | (2.916Mb) |
Abstract: | ABSTRACT: Phenol was chemically attached to low molecular weight chlorinated polyisobutylene and stearic acid respectively. These phenolic antioxidants were characterised by IR, 1H NMR and TGA. The efficiency and permanence of these bound antioxidants were compared with conventional antioxidants in natural rubber vulcanisates. The vulcanisates showed comparable ageing resistance in comparison to vulcanisates containing conventional antioxidants. The presence of liquid polymer bound phenol reduce the amount of plasticiser required for compounding. |
URI: | http://dyuthi.cusat.ac.in/purl/862 |
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P B Sulekha and ... reparation and...,2003.PDF | (6.967Mb) |
Abstract: | Polymers exhibit low electron density and they are radiolucent. Polymers can be made radiopaque by different techniques. We report a method for the preparation of radiopaque material from natural rubber (NR). NR in its latex form was iodinated. Iodinated natural rubber (INR) was characterized by using UV, thermo gravimetric analysis (TGA), and X-ray images. INR was compounded at high and low temperatures and its physical properties were measured. The low temperature cured samples show good radiopacity and conductivity. The optical density of low temperature cured samples was measured. |
URI: | http://dyuthi.cusat.ac.in/purl/818 |
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V S Nisha and R ... aration and...,Feb2006.PDF | (4.260Mb) |
Abstract: | Low-protein content natural rubber latex was produced by using a nonionic surfactant-polyethylene glycol (PEG). Extractable protein content of natural rubber latex was found to decrease with PEG treatment and reduction increased with increase in the molecular weight of PEG. The low-protein latex samples were characterized by tensile testing, Fourier transform infrared and thermogravimetric analysis. The results have shown 35% reduction in the extractable protein content, without any compromise on the mechanical properties of the latex; however, thermal stability of low-protein latex was found to be reduced marginally with PEG treatment. |
URI: | http://dyuthi.cusat.ac.in/xmlui/purl/2000 |
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Preparation of low-protein ....pdf | (172.3Kb) |
Abstract: | Plane-wave transmission gratings were stored in the same location of silver- doped photopolymer ¯lm using peristrophic multiplexing techniques. Constant and vari- able exposure scheduling methods were adopted for storing gratings in the ¯lm using He{Ne laser (632.8 nm). The role of recording geometry on the dynamic range of the ma- terial was studied by comparing the results obtained from both techniques. Peristrophic multiplexing with rotation of the ¯lm in a plane normal to the bisector of the incident beams resulted in better homogenization of di®raction e±ciencies and larger M/# value. |
Description: | Pramana { J. Phys., Vol. 75, No. 6, December 2010 |
URI: | http://dyuthi.cusat.ac.in/purl/4013 |
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Recording multi ... istrophic multiplexing.pdf | (389.8Kb) |
Abstract: | It is observed that reclamation of natural rubber latex based rubber using 2,2'-dibenzamidodiphenvldisulphide as reclaiming agent is an optional methodology for recycling of waste latex rubber (WLR). For progressive replacement of virgin natural rubber by the reclaim, two alternatives curing system were investigated: adjustment or reduction of the curing system with increasing reclaim content, to compensate for the extra amount of curatives brought along by the reclaim. For fixed curing system, as if the reclaim were equivalent to virgin NR. The cure behavior, final crosslink density and distribution, mechanical properties, and dynamic viscoelastic properties of the blends with reclaimed WLR are measured and compared with the virgin compound. The morphology of the blends, sulfur migration, and final distribution are analyzed.The mechanical and dynamic viscoelastic properties deteriorate for both curing systems, but to a lesser extent for fixed curing system compared to adjusted curing system. With the fixed cure system, many properties like tensile strength and compression set do still deteriorate, but tan 6 and Mrrr„/Murxr, representative for the rolling resistance of tires are improved. On the other hand, with the adjusted cure system both mechanical and dynamic properties still deteriorate. |
URI: | http://dyuthi.cusat.ac.in/purl/820 |
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V V Rajan and o ... cling of NR...,Feb2006.PDF | (9.335Mb) |
Abstract: | A new photopolymerizable recording media is introduced based on poly (vinyl alcohol) and vinyl acetate sensitized with methylene blue. It is observed that this MBPVA/VAc system can be reused a number of times without significant decrease in diffraction efficiency. The PVA-VAc ratio was optimized at 2:1. Diffraction efcienc4y of 6.3% was obtained without any fixing at a dye concentration of 9.3 x 10- mol/l at an exposure of 750mJ/cm2. The material is attractive on account of its reusability. |
URI: | http://dyuthi.cusat.ac.in/purl/796 |
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Beena Mary John ... recording...,march2005.PDF | (7.043Mb) |
Abstract: | ABSTRACT: The rheological and extrudate behaviour of natural rubber/latex reclaim blends were evaluated using a capillary viscometer . The study shows that the viscosity of natural rubber decreases marginally on the addition of latex reclaim while the variation of viscosity with shear rate is not affected. The temperature sensitivity of the blends is not affected significantly with the addition of latex reclaim . The extrudates of natural rubber/latex reclaim blends are smooth up to the addition of about 50 wt. percent latex reclaim in filled natural rubber compounds. |
URI: | http://dyuthi.cusat.ac.in/purl/842 |
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Reena Susan Geo ... Rheological and..,1995.PDF | (5.735Mb) |
Abstract: | Fully burnt rice hull (rice hull ash) was tried as a low cost filler in place of precipitated silica in NBR/PVC based microcellular soles. The mechanical properties of the soles containing silica and ash are found to be comparable. The expansion is marginally higher in the presence of ash, which permits to reduce the amount of blowing agent. Cell structure of microcellular sheets remains unchanged when silica is replaced by ash. |
URI: | http://dyuthi.cusat.ac.in/purl/867 |
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R Srilathakutty ... ,Rice hull ash...,2002.PDF | (4.693Mb) |
Abstract: | ABSTRACT: Rubber seed oil was used as a multipurpose ingredient in natural rubber (NR) and styrene butadiene rubber (SBR) compounds. The study shows that the oil, when substituted for conventional plasticiser, imparts excellent mechanical properties to NR and SBR vulcanizates. Further, it also improves aging resistance, reduces cure time, increases abrasion resistance and flex resistance, and reduces blooming. |
URI: | http://dyuthi.cusat.ac.in/purl/871 |
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V Nandanan and ... er seed oil...,Aug1998.PDF | (4.054Mb) |
Abstract: | Rubber solutions were prepared and used for bonding wood pieces. The effect of the variation of chlorinated natural rubber (CNR) and phenolformaldehyde (PF) resin in the adhesive solutions on lap shear strength was determined. Natural rubber and neoprene-based adhesive solutions were compared for their lap shear strength. The storage stability of the adhesive prepared was determined. The change in lap shear strength before and after being placed in cold water, hot water, acid, and alkali was tested. The bonding character of these adhesives was compared with different commercially available solution adhesives. The room-temperature aging resistance of wood joints was also determined. In all the studies, the adhesive prepared in the laboratory was found to be superior compared to the commercial adhesives. |
URI: | http://dyuthi.cusat.ac.in/purl/859 |
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Neetha John and ... er solution...,Oct1997.PDF | (3.485Mb) |
URI: | http://dyuthi.cusat.ac.in/purl/835 |
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Rani Joseph an ... anning electron..,1987.PDF | (6.459Mb) |
Abstract: | A comprehensive overview of reclamation of cured rubber with special emphasis on latex reclamation is depicted in this paper. The latex industry has expanded over the years to meet the world demands for gloves, condoms, latex thread, etc. Due to the strict specifications for the products and the unstable nature of the latex as high as 15% of the final latex products are rejected. As waste latex rubber (WLR) represents a source of high-quality rubber hydrocarbon, it is a potential candidate for generating reclaimed rubber of superior quality. The role of the different components in the reclamation recipe is explained and the reaction mechanism and chemistry during reclamation are discussed in detail. Different types of reclaiming processes are described with special reference to processes, which selectively cleave the cross links in the vulcanized rubber. The state-of-the-art techniques of reclamation with special attention on latex treatment are reviewed. An overview of the latest development concerning the fundamental studies in the field of rubber recycling by means of low-molecular weight compounds is described. A mathematical model description of main-chain and crosslink scission during devulcanization of a rubber vulcanizate is also given. |
URI: | http://dyuthi.cusat.ac.in/purl/821 |
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V V Rajan and o ... d techology...,Aug2006.PDF | (17.94Mb) |
Abstract: | Filled and gum compounds of Isobutylene-Isoprene rubber were extruded through a laboratory extruder at various feeding rates, different temperatures and revolutions per minute. The extruded compounds were vulcanized up to their optimum cure times and the mechanical properties of the vulcanizates were determined. The properties suggest that there is a particular feeding rate in the starved fed region, which results in maximum mechanical properties. The study shows that running the extruder at a slightly starved condition is an attractive means of improving the physical properties. |
URI: | http://dyuthi.cusat.ac.in/purl/864 |
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P J Joseph Fran ... icance of..,Dec1996PDF.PDF | (6.623Mb) |
Abstract: | Incorporation of silver ions into a dye-sensitized poly(vinyl alcohol)/acrylamide photopolymer is observed to give better performance compared to other metal-ion-doped photopolymer holographic recording media. Plane-wave transmission gratings were recorded in the photopolymer films using a He–Ne laser, and various holographic parameters were optimized so as to explore maximum potential of the material for various holographic applications. Silver-doped films showed good energy sensitivity, and gratings recorded in optimized film exhibited a diffraction efficiency of more than 75%. The potential of the material for holographic data storage applications is also studied using peristrophic multiplexing |
Description: | 20 April 2009 / Vol. 48, No. 12 / APPLIED OPTICS |
URI: | http://dyuthi.cusat.ac.in/purl/4715 |
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Silver-doped ph ... holographic recording.pdf | (787.8Kb) |
Abstract: | Filled compounds of natural rubber, isobutylene-isoprene rubber and styrene-butadiene rubber compounds were extruded through a laboratory extruder by varying the feeding rate at different temperatures and revolutions per minute. The extruded compounds were vulcanized up to their optimum cure times and the mechanical properties of the vulcanizates were determined. The properties suggest that there is a particular feeding rate in the starved fed region which results in maximum mechanical properties. The study shows that running the extruder at a slightly starved condition is an attractive means of improving the physical properties. |
URI: | http://dyuthi.cusat.ac.in/purl/831 |
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P J Joseph Fran ... rved extrusion...,1997.PDF | (7.505Mb) |
Abstract: | Gum and filled compounds of styrene-butadiene rubber are extruded through a laboratory extruder by varying the feeding rase at different temperatures and screw speed (rpm). The extruded compounds are vulcanized up4o their optimum cure times and the mechanical properties of the vulcanizates are determined. From the properties data obtained it Is concluded that there is a specific feeding rate wit in the starved fed region, which results In maximum Improved mechanical properties . The enhancement In properties is found to be due to better thermal and shear homogeneity. |
URI: | http://dyuthi.cusat.ac.in/purl/865 |
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P J Joseph fran ... rved feeding..,Jan1997.PDF | (4.492Mb) |
Abstract: | A carbon black filled 50/50 natural rubber (NR)/styrene-butadiene rubber (SBR) blend is vulcanized using several conventional curing systems designed by varying the amounts of sulphur and accelerator. The cure characteristics and the properties of the vulcanizates are compared. The quantity and quality of crosslinks in each case are evaluated by chemical probes to correlate them with the properties. |
URI: | http://dyuthi.cusat.ac.in/purl/838 |
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Rani Joseph and others,Studies on..Jan1987.PDF | (6.184Mb) |
Abstract: | ABSTRACT: The electrical conductivity of silicone rubber vulcanizates containing carbon blacks [e.g., acetylene black, lamp black, and ISAF (N-234) black] were investigated. The change in electrical conductivity with varying amounts of carbon blacks and the temperature dependence was measured. The mechanical properties like tensile strength, tear strength, elongation at break, hardness, etc., of the vulcanizates were determined. A comparative study of the electrical conductivity of the composites revealed that the electrical conductivity of the composites made with acetylene black was higher than that of the composites made of other blacks. |
URI: | http://dyuthi.cusat.ac.in/purl/853 |
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K G Princy and ... conductive...,Dec1997.PDF | (5.427Mb) |
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