Download or read book Thermoplastic Vulcanizates Based on Hydrogenated Natural Rubber Polypropylene Blends written by Korn Taksapattanakul and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The non-catalytic hydrogenation of natural rubber latex (NRL) was carried out by using diimide generated in situ from the reaction between hydrazine (N2H4) and hydrogen peroxide (H2O2). The effects of mole ratios of [C=C]:[N2H4]:[H2O2], reaction conditions, solvent types, solvent volumes and reaction scale-up on the hydrogenation levels were investigated. Nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), and Raman spectroscopic techniques were employed to investigate the chemical structure of the hydrogenated natural rubber (HNRs) and to quantify the hydrogenationlevels. It was found that variations in moles of N2H4 and H2O2 in the range of 1.0-2.0 moles resulted in degrees of hydrogenation in the range of 10-18%. Little improvement in hydrogenation levels of HNRs was obtained when NRL particles were swollen in solvents by which toluene yielded better results than hexane. The increase in toluenevolume resulted in the increase in hydrogenation levels up to 42 %. TEM micrographs revealed that swelling mainly occurred at the surface of NRL particles, implying that hydrogenation reaction confined largely at the surface of NRL particles. After removal of toluene, particle size and particle size distribution of partially hydrogenated NRL remained unchanged. To further improve degrees of hydrogenation, the reaction volume was extended and 65% hydrogenation levels were obtained. Therefore, 14%HNR, 33%HNR, and 65%HNR were successfully prepared under suitable reaction conditions. However, crosslinking and cis-trans isomerization were side-reactions occurring during hydrogenation. Gel and trans contents increased with increasing hydrogenation levels, leading to the increase in hardness of HNRs. Mooney viscosities of HNRs increased with increasing degrees of hydrogenation due to the increased gel contents. Mooney torquerelaxation of NR and HNRs were similar. Thermogravimetric analysis revealed that vi HNRs had greater thermal stability than NR and thermal stability increased with increasing degrees of hydrogenation. HNR vulcanizates were much better resistant to ozone and UV than cured NR. Sulfur-vulcanized rubbers had greater ozone resistance than peroxide-cure rubbers due to less amounts of carbon-carbon double bonds present in rubbers. In addition, modulus at low strain and tensile strength of sulfur-cured rubbers were higher than those of peroxide-cured rubbers, but lower elongation due to higher crosslink densities. Also, modulus at low strain and tensile strength increased with increasing hydrogenation levels of HNRs, in contrast to strain at break. Thermoplastic vulcanizates (TPVs) from blends of HNR and Polypropylene (PP) were prepared via dynamic vulcanization using peroxide and sulfur as curing agents. The effects of blend ratios on mechanical properties of TPVs were investigated. Tensile strength increased with increasing PP portions, but breaking strain decreased. Morphology of TPVs was characterized with Raman mapping and scanning electron microscope (SEM). The phase sizes of crosslinked rubber obtained from both techniques were correlated well.
Download or read book Polypropylene and Natural Rubber Based Thermoplastic Vulcanizates by Electron Induced Reactive Processing written by Manas Mondal and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study to Develop Thermoplastic Elastomers from Natural Rubber and Plastic Blends written by Wannee Surangsopon and published by . This book was released on 1991 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Industrial Applications of Biopolymers and their Environmental Impact written by Abdullah Al Mamun and published by CRC Press. This book was released on 2020-11-23 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biopolymers represent a carbon emission solution: they are green and eco-friendly with a variety of uses in biomedical engineering, the automotive industry, the packaging and paper industries, and for the development of new building materials. This book describes the various raw materials of biopolymers and their chemical and physical properties, the polymerization process, and the chemical structure and properties of biopolymers. Furthermore, this book identifies the drawbacks of biopolymers and how to overcome them through modification methods to enhance the compatibility, flexibility, physicochemical properties, thermal stability, impact response, and rigidity.
Download or read book Current Topics in Elastomers Research written by Anil K. Bhowmick and published by CRC Press. This book was released on 2008-05-07 with total page 1105 pages. Available in PDF, EPUB and Kindle. Book excerpt: From weather-proof tires and artificial hearts to the o-rings and valve seals that enable successful space exploration, rubber is an indispensable component of modern civilization. Stiff competition and stringent application requirements foster continuous challenges requiring manufacturers to fund ever-expanding research projects. However, this vas
Download or read book Thermoplastic Natural Rubber Blends written by D. J. Elliott and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rubberwood Filled Polypropylene natural Rubber Blends written by Salmah and published by . This book was released on 2000 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrogenated Skim Natural Rubber Prepared by Diimide Reduction and Its Vulcanizates written by and published by . This book was released on 2008 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogenation is an important method of chemical modification, which improves the physical, chemical and thermal properties of diene based polymers. Skim natural rubber latex (SNRL) produced as a by-product from the production of concentrated natural rubber latex, could be hydrogenated to a strictly alternating ethylene-propylene copolymer (EPDM) by diimide reduction, using hydrazine and hydrogen peroxide with copper sulfate as catalyst. The hydrogenated products were characterized by FTIR and NMR spectroscopy. The effect of various reaction parameters on the hydrogenation level, were investigated. Low temperature, long reaction time, high amount of hydrazine and lesser amount of hydrogen peroxide and copper sulfate were required to optimize the hydrogenation reaction of SNRL. Copper acetate was a highly active catalyst for the reaction. The kinetic result indicated that the diimide hydrogenation of SNRL exhibited a first order behavior with respect to the C=C concentration. The activation energy of catalytic and non-catalytic diimide hydrogenation of SNRL was 9.5 and 21.1 kJ/mol, respectively. The thermogravimetric analysis indicated that the thermal stability of hydrogenated skim natural rubber (HSNR) was higher than their parent polymer. From TEM micrograph of hydrogenated SNRL particles, non-hydrogenated rubber core and hydrogenated rubber layer were observed according to the layer model. The particle size and particle size distribution of hydrogenated SNRL were not changed during hydrogenation. In addition, the mechanical properties and ozone resistance of vulcanized HSNR blends were also investigated. The increase in HSNR content in the blends could retard the ozonolysis resulting in the surface cracking.
Download or read book Dynamic Vulcanization of Rubberwood filled Polypropylene natural Rubber Blends written by Salmah and published by . This book was released on 2001 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermoplastic Natural Rubber written by Maswanee Narathichat and published by LAP Lambert Academic Publishing. This book was released on 2011-10 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoplastic elastomers (TPEs) are rubbery materials with properties and functional performance similar to those of conventional vulcanized rubber. Interest in natural rubber (NR) and thermoplastic blends (TPNRs) has also been increased recently. By blending with polar thermoplastics such as polyamide-12 (PA-12), epoxidized natural rubber (ENR) is one of the modified NR forms used to prepare TPNRs which improves compatibility of the polymer pairs. Blend compatibility was promoted because of interaction between oxirane rings in ENR and polar functional groups in polyamide molecules (i.e. -NH2, -COOH, -NH-CO-) and hence the blend properties. Temperature scanning stress relaxation (TSSR) measurement revealed an improvement in stress relaxation behaviour and thermal resistance of the blends with ENR. Moreover, it is possible to apply the TSSR to determine the compatibility of the blends based on the temperature coefficient ( .max) value in combination with ATR-FTIR technique.
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation of Thermoplastic Vulcanizates from Devulcanized Rubber and Polypropylene written by Prashant Mutyala and published by . This book was released on 2013 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the current problems faced by mankind is the problem of safe disposal of waste rubber. Statistics show that the number of waste tires is continuously increasing at a very rapid rate. Since rubber materials do not decompose easily (due to their crosslinked structure), they end up being a serious 'environmental problem'. An intuitive solution to prevent the accumulation of the scrap tires is to continuously reuse them. A new patented reclamation method was discovered in our laboratory, which makes use of a twin screw extruder (TSE) in order to produce reclaimed rubber (referred as devulcanized rubber (DR) from here on) of very high quality. Also, this method has proven to be more economical than other commercial reclaiming methods. Products made solely from a reclaimed material face challenges from those made by virgin materials because of relatively poor properties. However, the striking advantage of using reclaimed rubbers is the cost reduction. Hence, it is important to work on establishing methods by which these reclaimed rubbers could be efficiently used and incorporated into present day products. The deterioration of properties could be minimized by blending them with varying amounts of other materials. A possibility in this direction is manufacturing of thermoplastic vulcanizates (TPVs) using reclaimed rubber and general purpose thermoplastics. In accordance with this idea, the focus of this research is to prepare DR and polypropylene (PP) based TPVs. DR is unique as the rubber itself consists of two phases- one phase consisting of uncrosslinked (including devulcanized rubber molecules), and the other phase consisting of crosslinked (un-devulcanized) rubber. These un-devulcanized crumbs act as stress concentrators because they do not break-up easily, and lead to poor physical properties. Hence, this project tries to find out ways to increase the interfacial adhesion between the rubber and PP by using reactive and non-reactive techniques.
Download or read book Study on Mechanical Property of Thermoplastic Elastomers Contained Natural Rubber with Polypropylene and Natural Rubber with High Density Polyethylene written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermoplastic Natural Rubbers Based on Natural Rubber NR and Ethylene Vinyl Acetate Copolymer EVA with Natural Rubber graft Poly dimethyl methacryloyloxymethyl phosphonate NR g PDMMMP as Compatibilizer written by Punyanich Intharapat and published by . This book was released on 2009 with total page 594 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graft copolymers of natural rubber and poly(dimethyl(acryloyloxymethyl)phosphonate) (NR-g-PDMAMP), natural rubber and poly(dimethyl(methacryloyloxyethyl)phosphonate) (NR-g-PDMMEP), and natural rubber and poly(dimethyl(methacryloyloxymethyl)phosphonate) (NR-g-PDMMMP), were prepared in latex medium via a "grafting from" methodology based on the photopolymerization of vinyl monomers initiated from N,N-diethyldithiocarbamate groups previously bound in side position of the 1,4-polyisoprene chains of natural rubber. Thereafter, compatibilization studies of natural rubber (NR) / ethylene vinyl acetate copolymer (EV A) blends were considered using NR-g-PDMMMP as a blend compatibilizer. The investigations were carried out on two categories of blends : uncured 50/50 and dynamically cured 40/60 NR/EV A blends. ln the two cases, the influences of NR-g-PDMMMP grafting rates (i.e., 71, 80, 89, and 95 %) and of loading level in compatibilizer (i.e., 0, 1,3,5,7,9,12, and 15 wt% compared to NR) on rheological, dynamical, mechanical, morphological, and thermal properties, were studied. The best compatibilization effects were observed with a NR-g-PDMMMP having a grafting rate equal to 80 %, at a loading level of 7 wt% for 50/50 uncured blend and 9 wt% for 40/60 dynamically cured blend. In these conditions, the highest complex viscosity (positive deviation), tensile strength, and elongation at break, as well as the lowest values of tension set and tan d (damping factor), were observed. SEM micrographs of compatibilized blends showed a size decrease of the domains. It was also noted that the thermal stability of NR/EV A blends was improved by incorporating NR-g-PDMMMP.
Download or read book Natural Rubber Based Thermoplastic Elastomers written by A. J. Tinker and published by . This book was released on 1988 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polymer Blends Handbook written by L. A. Utracki and published by . This book was released on 2014-01-31 with total page 1800 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by an international group of highly respected contributors, this fundamental reference work covers all aspects of polymer blends: science, engineering, technology and applications.
Download or read book Thermoplastic Vulcanizate Nanocomposites Based on Polypropylene ethylene Propylene Diene Terpolymer PP EPDM Prepared by Reactive Extrusion written by Amin Mirzadesh and published by . This book was released on 2012 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt:
