Rubber elongation factor (REF, a major allergen component in Hevea brasiliensis latex has amyloid properties.

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Karine Berthelot

Full Text Available REF (Hevb1 and SRPP (Hevb3 are two major components of Hevea brasiliensis latex, well known for their allergenic properties. They are obviously taking part in the biosynthesis of natural rubber, but their exact function is still unclear. They could be involved in defense/stress mechanisms after tapping or directly acting on the isoprenoid biosynthetic pathway. The structure of these two proteins is still not described. In this work, it was discovered that REF has amyloid properties, contrary to SRPP. We investigated their structure by CD, TEM, ATR-FTIR and WAXS and neatly showed the presence of β-sheet organized aggregates for REF, whereas SRPP mainly fold as a helical protein. Both proteins are highly hydrophobic but differ in their interaction with lipid monolayers used to mimic the monomembrane surrounding the rubber particles. Ellipsometry experiments showed that REF seems to penetrate deeply into the monolayer and SRPP only binds to the lipid surface. These results could therefore clarify the role of these two paralogous proteins in latex production, either in the coagulation of natural rubber or in stress-related responses. To our knowledge, this is the first report of an amyloid formed from a plant protein. This suggests also the presence of functional amyloid in the plant kingdom.

Rubber particle proteins REF1 and SRPP1 interact differently with native lipids extracted from Hevea brasiliensis latex.

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Wadeesirisak, Kanthida; Castano, Sabine; Berthelot, Karine; Vaysse, Laurent; Bonfils, Frédéric; Peruch, Frédéric; Rattanaporn, Kittipong; Liengprayoon, Siriluck; Lecomte, Sophie; Bottier, Céline

2017-02-01

Rubber particle membranes from the Hevea latex contain predominantly two proteins, REF1 and SRPP1 involved in poly(cis-1,4-isoprene) synthesis or rubber quality. The repartition of both proteins on the small or large rubber particles seems to differ, but their role in the irreversible coagulation of the rubber particle is still unknown. In this study we highlighted the different modes of interactions of both recombinant proteins with different classes of lipids extracted from Hevea brasiliensis latex, and defined as phospholipids (PL), glycolipids (GL) and neutral lipids (NL). We combined two biophysical methods, polarization modulated-infrared reflection adsorption spectroscopy (PM-IRRAS) and ellipsometry to elucidate their interactions with monolayers of each class of lipids. REF1 and SRPP1 interactions with native lipids are clearly different; SRPP1 interacts mostly in surface with PL, GL or NL, without modification of its structure. In contrast REF1 inserts deeply in the lipid monolayers with all lipid classes. With NL, REF1 is even able to switch from α-helice conformation to β-sheet structure, as in its aggregated form (amyloid form). Interaction between REF1 and NL may therefore have a specific role in the irreversible coagulation of rubber particles. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of the natural rubber from new rubber tree clones of PB 300 series

International Nuclear Information System (INIS)

Silva, Maycon J.; Spinelli, Rafaela O.; Moreno, Rogerio M.B.; Mattoso, Luiz H.C.; Martins, Maria Alice; Scaloppi Junior, Erivaldo J.

2015-01-01

The natural rubber (NR) is present in more than 2500 species of plants, being the Hevea brasiliensis the most commercially exploited. It is a raw material of great importance to the Brazilian economy, but the country faces a production's deficit, having to import about 60% of its consumption. In this work , the latex obtained from rubber tree of new clones of PB series 300 (PB 311, PB 312, PB 314 , PB 326, PB 346 and PB 350 ) and RRIM 600 (control) were characterized by dry rubber content (DRC), total solids content, distribution of particle size, Zeta potential, thermogravimetry, differential scanning calorimetry, infrared in the spectroscopy (FTIR), nuclear magnetic resonance (NMR) and technological properties. The DRC values ranged from 33% to 40%, and total solids of 38% to 44%. All of the clones showed average particle diameter between 180.0 to 192.1 nm, excluding clones PB 326 and PB 346 with 150.0 nm and 157.9 nm, respectively. The NMR spectra and FTIR showed that the structure of the natural rubber from all clones studied is cis -1,4- polyisoprene. Natural rubber from the new clones showed good thermal stability up to 285 °C and glass transition temperature of -64 °C. (author)

Silencing the lettuce homologs of small rubber particle protein does not influence natural rubber biosynthesis in lettuce (Lactuca sativa).

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Chakrabarty, Romit; Qu, Yang; Ro, Dae-Kyun

2015-05-01

Natural rubber, cis-1,4-polyisoprene, is an important raw material in chemical industries, but its biosynthetic mechanism remains elusive. Natural rubber is known to be synthesized in rubber particles suspended in laticifer cells in the Brazilian rubber tree (Hevea brasiliensis). In the rubber tree, rubber elongation factor (REF) and its homolog, small rubber particle protein (SRPP), were found to be the most abundant proteins in rubber particles, and they have been implicated in natural rubber biosynthesis. As lettuce (Lactuca sativa) can synthesize natural rubber, we utilized this annual, transformable plant to examine in planta roles of the lettuce REF/SRPP homologs by RNA interference. Among eight lettuce REF/SRPP homologs identified, transcripts of two genes (LsSRPP4 and LsSRPP8) accounted for more than 90% of total transcripts of REF/SRPP homologs in lettuce latex. LsSRPP4 displays a typical primary protein sequence as other REF/SRPP, while LsSRPP8 is twice as long as LsSRPP4. These two major LsSRPP transcripts were individually and simultaneously silenced by RNA interference, and relative abundance, polymer molecular weight, and polydispersity of natural rubber were analyzed from the LsSRPP4- and LsSRPP8-silenced transgenic lettuce. Despite previous data suggesting the implications of REF/SRPP in natural rubber biosynthesis, qualitative and quantitative alterations of natural rubber could not be observed in transgenic lettuce lines. It is concluded that lettuce REF/SRPP homologs are not critically important proteins in natural rubber biosynthesis in lettuce. Copyright © 2014 Elsevier Ltd. All rights reserved.

Distribuição espacial e plano de amostragem de Calacarus heveae (Acari em seringueira Spatial distribution and sampling plan for Calacarus heveae (Acari on rubber trees

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Noeli Juarez Ferla

2007-12-01

Full Text Available Calacarus heveae Feres, 1992 é um eriofídeo descrito de espécimes coletados em plantas de seringueira (Hevea brasiliensis, Euphorbiaceae na região noroeste do Estado de São Paulo. Esse ácaro prefere a face adaxial dos folíolos e pode causar a perda do brilho, amarelecimento, bronzeamento dessa região e a subseqüente queda prematura das folhas. O objetivo deste trabalho foi analisar a distribuição de C. heveae em seringueira, selecionar a unidade de amostragem mais representativa e desenvolver um plano de amostragem para o estudo de sua flutuação populacional. O trabalho foi conduzido com os clones PB 260 e IAN 873, respectivamente nos municípios de Itiquira e de Pontes e Lacerda, ambos no Mato Grosso. Em Itiquira, diferenças significativas foram observadas em quatro ocasiões em relação ao número médio de ácaros por folha nos diferentes estratos das plantas. Nas amostragens realizadas em Pontes e Lacerda, nenhuma diferença significativa foi encontrada entre os estratos em relação àquele parâmetro. Apenas em Itiquira, em uma ocasião de amostragem, foi verificada diferença entre os três estratos, em relação à proporção de folhas infestadas. Nenhuma diferença significativa foi verificada em relação ao número médio de ácaros por folha e proporção de folhas infestadas por C. heveae a diferentes distâncias da periferia da copa. Calacarus heveae exibe distribuição agregada no campo. Para estimar a densidade de C. heveae, um plano numérico e um plano binomial de amostragem foram desenvolvidos.Calacarus heveae Feres, 1992 (Eriophyidae is a mite described from specimens collected on rubber tree (Hevea brasiliensis, Euphorbiaceae in the northwest region of the state of São Paulo. This mite prefers the adaxial face of the folioles which it can turn dry, yellowish and brownish; it can also cause leaf fall. The aim of this work was to analyze the distribution of C. heveae on rubber trees, to select the most

Time series analysis of the behavior of brazilian natural rubber

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Antônio Donizette de Oliveira

2009-03-01

Full Text Available The natural rubber is a non-wood product obtained of the coagulation of some lattices of forest species, being Hevea brasiliensis the main one. Native from the Amazon Region, this species was already known by the Indians before the discovery of America. The natural rubber became a product globally valued due to its multiple applications in the economy, being its almost perfect substitute the synthetic rubber derived from the petroleum. Similarly to what happens with other countless products the forecast of future prices of the natural rubber has been object of many studies. The use of models of forecast of univariate timeseries stands out as the more accurate and useful to reduce the uncertainty in the economic decision making process. This studyanalyzed the historical series of prices of the Brazilian natural rubber (R$/kg, in the Jan/99 - Jun/2006 period, in order tocharacterize the rubber price behavior in the domestic market; estimated a model for the time series of monthly natural rubberprices; and foresaw the domestic prices of the natural rubber, in the Jul/2006 - Jun/2007 period, based on the estimated models.The studied models were the ones belonging to the ARIMA family. The main results were: the domestic market of the natural rubberis expanding due to the growth of the world economy; among the adjusted models, the ARIMA (1,1,1 model provided the bestadjustment of the time series of prices of the natural rubber (R$/kg; the prognosis accomplished for the series supplied statistically adequate fittings.

Expression and characterization of active site mutants of hevamine, a chitinase from the rubber tree Hevea brasiliensis

NARCIS (Netherlands)

Bokma, Evert; Rozeboom, Henriëtte J.; Sibbald, Mark; Dijkstra, Bauke W.; Beintema, Jaap J.

Hevamine is a chitinase from the rubber tree Hevea brasiliensis. Its active site contains Asp125, Glu127, and Tyr183, which interact with the -1 sugar residue of the substrate. To investigate their role in catalysis, we have successfully expressed wild-type enzyme and mutants of these residues as

Determination of cDNA and genomic DNA sequences of hevamine, a chitinase from the rubber tree Hevea brasiliensis

NARCIS (Netherlands)

Bokma, E; Spiering, M; Chow, KS; Mulder, PPMFA; Subroto, T; Beintema, JJ

Hevamine is a chitinase from the rubber tree Hevea brasiliensis and belongs to the family 18 glycosyl hydrolases. This paper describes the cloning of hevamine DNA and cDNA sequences. Hevamine contains a signal peptide at the N-terminus and a putative vacuolar targeting sequence at the C-terminus

Similaridade genética entre clones de seringueira (Hevea brasiliensis, por meio de marcadores RAPD Genetic similarity among rubber tree (Hevea brasiliensis clones using RAPD markers

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Karine Cristina Bicalho

2008-10-01

Full Text Available A seringueira [Hevea brasiliensis (Willd. ex. Adr. de Juss Muell.-Arg.] é uma espécie nativa da região amazônica e compreende a maior fonte produtora de borracha natural do mundo. Na busca de condições mais favoráveis ao cultivo, além da busca pela auto-suficiência na produção de borracha natural, o cultivo da seringueira migrou para outras regiões do país. Objetivou-se, com o presente trabalho, estimar a similaridade genética de genótipos de seringueira, provenientes de regiões distintas do país, Lavras-MG (UFLA e Campinas-SP (IAC, por meio de marcadores moleculares RAPD. A análise foi efetuada em 41 indivíduos, representados por 17 genótipos diferentes, com base em 19 primers, que geraram 121 fragmentos polimórficos. Os dados foram analisados utilizando o software NTSYS-pc - 2.1, por meio do coeficiente de Dice e pelo método das médias (UPGMA. A similaridade genética entre o material analisado variou de 0,56 a 1,00. Na análise do dendrograma, foram observados 18 grupos. Os clones (RRIM600, GT1, PB235, PL PIM e FX2261, utilizados em diferentes repetições, foram idênticos, quando comparados entre si, entretanto o mesmo não foi observado para os clones identificados como RRIM 701. Os resultados obtidos sugerem que o material avaliado na UFLA é o mesmo implantado no IAC, exceto o RRIM 701, mostrando uma ampla variabilidade genética, disponível para estudos e propagação da cultura.The rubber tree [Hevea brasiliensis (Willd. ex. Adr. de Juss Muell.-Arg.] is a native species from Amazon region, and represents the biggest source of natural rubber in the world.. However, the rubber tree culture has had an expansion to other brazilian regions, in search of more favorable conditions for its cultivation and self-sufficiency in natural rubber. The aim of this work was to estimate genetic similarity among rubber tree clones, from different Brazilian regions, Lavras (UFLA and Campinas (IAC, by using RAPD molecular markers

The rubber tree genome reveals new insights into rubber production and species adaptation

OpenAIRE

Tang, Chaorong; Yang, Meng; Fang, Yongjun; Luo, Yingfeng; Gao, Shenghan; Xiao, Xiaohu; An, Zewei; Zhou, Binhui; Zhang, Bing; Tan, Xinyu; Yeang, Hoong Yeet; Qin, Yunxia; Yang, Jianghua; Lin, Qiang; Mei, Hailiang

2016-01-01

The Para rubber tree (Hevea brasiliensis) is an economically important tropical tree species that produces natural rubber, an essential industrial raw material. Here we present a high-quality genome assembly of this species (1.37 Gb, scaffold N50 = 1.28 Mb) that covers 93.8% of the genome (1.47 Gb) and harbours 43,792 predicted protein-coding genes. A striking expansion of the REF/SRPP (rubber elongation factor/small rubber particle protein) gene family and its divergence into several laticif...

Evapotranspiration of rubber (Hevea brasiliensis) cultivated at two plantation sites in Southeast Asia

Science.gov (United States)

Giambelluca, Thomas W.; Mudd, Ryan G.; Liu, Wen; Ziegler, Alan D.; Kobayashi, Nakako; Kumagai, Tomo'omi; Miyazawa, Yoshiyuki; Lim, Tiva Khan; Huang, Maoyi; Fox, Jefferson; Yin, Song; Mak, Sophea Veasna; Kasemsap, Poonpipope

2016-02-01

To investigate the effects of expanding rubber (Hevea brasiliensis) cultivation on water cycling in Mainland Southeast Asia (MSEA), evapotranspiration (ET) was measured within rubber plantations at Bueng Kan, Thailand, and Kampong Cham, Cambodia. After energy closure adjustment, mean annual rubber ET was 1211 and 1459 mm yr-1 at the Thailand and Cambodia sites, respectively, higher than that of other tree-dominated land covers in the region, including tropical seasonal forest (812-1140 mm yr-1), and savanna (538-1060 mm yr-1). The mean proportion of net radiation used for ET by rubber (0.725) is similar to that of tropical rainforest (0.729) and much higher than that of tropical seasonal forest (0.595) and savanna (0.548). Plant area index (varies with leaf area changes), explains 88.2% and 73.1% of the variance in the ratio of latent energy flux (energy equivalent of ET) to potential latent energy flux (LE/LEpot) for midday rain-free periods at the Thailand and Cambodia sites, respectively. High annual rubber ET results from high late dry season water use, associated with rapid refoliation by this brevideciduous species, facilitated by tapping of deep soil water, and by very high wet season ET, a characteristic of deciduous trees. Spatially, mean annual rubber ET increases strongly with increasing net radiation (Rn) across the three available rubber plantation observation sites, unlike nonrubber tropical ecosystems, which reduce canopy conductance at high Rn sites. High water use by rubber raises concerns about potential effects of continued expansion of tree plantations on water and food security in MSEA.

From rubber tree homeland to rubber tree plantation: Jacques Huber and his studies on the culture of heveas in the East (1911-1912

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Anna Raquel de Matos Castro

2009-12-01

Full Text Available The paper deals with the trip of the Swiss botanist Jacques Huber (1867-1914 to the main eastern rubber producing countries between 1911 and 1912. This trip was intended to develop studies on the cultivation of Hevea brasiliensis in that region. Huber was commissioned with the task by the State of Pará governor João Coelho, who wanted to find solutions to the downfall of the regional economy. The economy of Amazonia was primarily based on rubber extractivism and was seriously endangered due the market controlled by England from eastern plantations. Back to Brazil, Huber published a report with information about the society, economy and environment where the rubber trees were cultivated. The report compiles scientific observations and the topics that motivated the regional elites in that context. In addition to the brief analyses of the report, photographs took by Huber in the East of rubber trees plantations, tree tapping and local workers are published.

Genotype-environment interaction and phenotypic stability for girth growth and rubber yield of Hevea clones in São Paulo State, Brazil

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Gonçalves Paulo de Souza

2003-01-01

Full Text Available The best-yielding, best vigour and most stable Hevea clones are identified by growing clones in different environments. However, research on the stability in Hevea brasiliensis (Willd. Adr. ex Juss. Muell.-Arg. is scarce. The objectives of this work were to assess genotype-environment interaction and determine stable genotypes. Stability analysis were performed on results for girth growth and rubber yield of seven clones from five comparative trials conducted over 10 years (girth growth and four years (rubber yield in São Paulo State, Brazil. Stability was estimated using the Eberhart and Russell (1966 method. Year by location and location variability were the dominant sources of interactions. The stability analysis identified GT 1 and IAN 873 as the most stable clones for girth growth and rubber yield respectively since their regression coefficients were almost the unity (b = 1 and they had one of the lowest deviations from regressions (S2di. Their coefficient of determination (R² was as high as 89.5% and 89.8% confirming their stability. In contrast, clones such as PB 235, PR 261, and RRIM 701 for girth growth and clones such as GT 1 for rubber yield with regression coefficients greater than one were regarded as sensitive to environment changes.

Studies in the genus Hevea. VIII. Notes on Infraspecific variants of Hevea brasiliensis (Euphorbiaceae)

Energy Technology Data Exchange (ETDEWEB)

Schultes, R.E.

Supplying 98% of the world's natural rubber, Hevea brasiliensis has transformed life around the world in only a century. This species - one of 10 in its genus - gives the best natural rubber, but much more remains to be studied concerning the numerous localized strains of the species. The British introduced to the orient seeds from the lower Amazon - representatives of a not superior ecotype of the species but, at that time a century ago, the only available germ plasm. The time for study of the intraspecific variants of H. brasiliensis and their use in programs of genetic manipulation of the genus is long overdue. But basic to this desired program is a clear taxonomic understanding of infraspecific variants, still awaiting evaluation. Although numerous taxonomic treatments of subspecific variants have been offered, there is little available to give genetic programs concrete information.

Characterization of the natural rubber from new rubber tree clones of PB 300 series; Caracterizacao da borracha natural dos novos clones de seringueira da serie PB 300

Energy Technology Data Exchange (ETDEWEB)

Silva, Maycon J.; Spinelli, Rafaela O.; Moreno, Rogerio M.B.; Mattoso, Luiz H.C.; Martins, Maria Alice, E-mail: maria-alice.martins@embrapa.br [Embrapa Instrumentacao/LNNA, Sao Carlos, SP (Brazil); Scaloppi Junior, Erivaldo J. [Instituto Agronomico (IAC), Votuporanga, SP (Brazil). Centro de Seringueira e Sistemas Agroflorestais; Goncalves, Paulo de S. [Instituto Agronomico (IAC), Campinas, SP (Brazil)

2015-07-01

The natural rubber (NR) is present in more than 2500 species of plants, being the Hevea brasiliensis the most commercially exploited. It is a raw material of great importance to the Brazilian economy, but the country faces a production's deficit, having to import about 60% of its consumption. In this work , the latex obtained from rubber tree of new clones of PB series 300 (PB 311, PB 312, PB 314 , PB 326, PB 346 and PB 350 ) and RRIM 600 (control) were characterized by dry rubber content (DRC), total solids content, distribution of particle size, Zeta potential, thermogravimetry, differential scanning calorimetry, infrared in the spectroscopy (FTIR), nuclear magnetic resonance (NMR) and technological properties. The DRC values ranged from 33% to 40%, and total solids of 38% to 44%. All of the clones showed average particle diameter between 180.0 to 192.1 nm, excluding clones PB 326 and PB 346 with 150.0 nm and 157.9 nm, respectively. The NMR spectra and FTIR showed that the structure of the natural rubber from all clones studied is cis -1,4- polyisoprene. Natural rubber from the new clones showed good thermal stability up to 285 °C and glass transition temperature of -64 °C. (author)

Evapotranspiration of rubber ( Hevea brasiliensis ) cultivated at two plantation sites in Southeast Asia: RUBBER EVAPOTRANSPIRATION IN SE ASIA

Energy Technology Data Exchange (ETDEWEB)

Giambelluca, Thomas W. [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya Japan; Mudd, Ryan G. [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Liu, Wen [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Ziegler, Alan D. [Department of Geography, National University of Singapore, Singapore Singapore; Kobayashi, Nakako [Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya Japan; Kumagai, Tomo' omi [Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya Japan; Miyazawa, Yoshiyuki [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Research Institute of East Asia Environments, Kyushu University, Fukuoka Japan; Lim, Tiva Khan [Cambodian Rubber Research Institute, Phnom Penh Cambodia; Huang, Maoyi [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Fox, Jefferson [East-West Center, Honolulu Hawai' i USA; Yin, Song [Cambodian Rubber Research Institute, Phnom Penh Cambodia; Mak, Sophea Veasna [Cambodian Rubber Research Institute, Phnom Penh Cambodia; Kasemsap, Poonpipope [Department of Horticulture, Kasetsart University, Bangkok Thailand

2016-02-01

The expansion of rubber (Hevea brasiliensis) cultivation to higher latitudes and higher elevations in southeast Asia is part of a dramatic shift in the direction of rural land cover change in the region toward more tree covered landscapes. To investigate the possible effects of increasing rubber cultivation in the region on ecosystem services including water cycling, eddy covariance towers were established to measure ecosystem fluxes within two rubber plantations, one each in Bueng Kan, northeastern Thailand, and Kampong Cham, central Cambodia. The results show that evapotranspiration (ET) at both sites is strongly related to variations in available energy and leaf area, and moderately controlled by soil moisture. Measured mean annual ET was 1128 and 1272 mm for the Thailand and Cambodia sites, respectively. After adjustment for energy closure, mean annual was estimated to be 1211 and 1459 mm yr at the Thailand and Cambodia sites, respectively. Based on these estimates and that of another site in Xishuangbanna, southwestern China, it appears that of rubber is higher than that of other tree dominated land covers in the region, including forest. While measurements by others in non rubber tropical ecosystems indicate that at high net radiation sites is at most only slightly higher than for sites with lower net radiation, mean annual rubber increases strongl with increasing net radiation across the three available rubber plantation observation sites. With the continued expansion of tree dominated land covers, including rubber cultivation, in southeast Asia, the possible association between commercially viable, fast growing tree crop species Giambelluca et al. Evapotranspiration of rubber (Havea brasiliensis) cultivated at two sites in southeast Asia and their relatively high water use raises concerns about potential effects on water and food security.

ADUBAÇÃO NPK E PRODUÇÃO DE BORRACHA SECA PELA SERINGUEIRA (Hevea brasiliensis NPK FERTILIZATION AND DRY RUBBER PRODUCTION BY Hevea brasiliensis TREES

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Marcos Roberto Murbach

1999-01-01

Full Text Available Instalou-se um experimento, na região de Garça, SP, em um solo Latossolo Vermelho escuro, A moderado, textura arenosa, com o objetivo de se avaliar a influência da adubação NPK sobre a produtividade de borracha seca da seringueira (Hevea brasiliensis clone "PB 235", com 13 anos de idade. O experimento foi instalado em blocos ao acaso, em esquema fatorial fracionário (1/443, totalizando 16 tratamentos e 4 repetições, onde se utilizaram 4 níveis de N (0, 80, 160, 320 kg ha-1, 4 de K2O (0, 80, 160, 320 kg ha-1 e 4 de P2O5 (0, 40, 80, 160 kg ha-1. A produção foi avaliada entre os mêses de outubro de 1995 a junho de 1996. Conclui-se que a adubação potássica aumentou a produtividade de borracha seca, o mesmo não ocorrendo com a adubação nitrogenada e fosfatada.An experiment was carried out to study the effects of nitrogen, phosphorus and potassium fertilizations on dry rubber yield of Hevea brasiliensis Muell Arg., clone PB 235 growing on a Dark Red-Yellow Latosol, in Garça-SP, Brazil. The experiment consisted of a (1/443 fractional factorial of randomized block design, with 16 treatments and 4 replicates, utilizing 4 levels of N (0, 80, 160 and 320 kg ha-1, 4 of P2O5 (0, 40, 80 and 160 kg ha-1 and 4 of K (0, 80, 160 and 320 kg ha-1. The rubber yield was evaluated monthly from October 1995 to June 1996. Results showed that potassium fertilization increased dry rubber yield, which was not affected by nitrogen and phosphate fertilizations.

Controle de oídio em seringueira e sua interferência na população do ácaro Calacarus heveae Feres Control of Oidium on rubber tree and it's interference on the mite Calacarus heveae Feres population

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Marineide Rosa Vieira

2006-09-01

Full Text Available A cultura da seringueira, Hevea brasiliensis (Willd. ex. Adr. de Juss. Müell. Arg., pode ser atacada pelo fungo Oidium heveae Steinm e pelo ácaro Calacarus heveae Feres, causadores de desfolha em seringais paulistas. O presente trabalho teve por objetivo avaliar o efeito do fungicida sistêmico fenarimol no controle do fungo e a sua interferência na população de C. heveae. Comparou-se a sua aplicação em quatro momentos: 1- uma aplicação no reenfolhamento das plantas (agosto; 2- uma aplicação em janeiro; 3- duas aplicações, uma no reenfolhamento e uma em março; 4 - quatro aplicações durante o ciclo da cultura. Nas quatro situações, o fungicida reduziu os sintomas da doença, entretanto houve ressurgência dos ácaros. Considerando-se o manejo conjunto de O. heveae e C. heveae o melhor resultado foi obtido com duas aplicações do fungicida.The rubber tree, Hevea brasiliensis (Willd. ex. Adr. de Juss. Müell. Arg., can be attacked by the Oidium heveae Steinm fungus and the Calacarus heveae Feres mite, which cause leaf fall in areas of the São Paulo State. This study had as objective the evaluation of the effect of the systemic fungicide fenarimol, in the fungus control and its interference on C. heveae population. Four ways of application were compared: one application during the new leaves growth period (August; one application in January; two applications: one in the new leaves growth period and one in March; four applications during the cycle of the culture. The fungicide reduced the disease symptoms in all the treatments; however mite resurgence was detected. Considering the integrated management of O. heveae and C. heveae the best result was obtained by using two applications of the fungicide.

Propagation and molecular characterisation of rubber tree (Hevea brasiliensis Muell. Arg) in Ghana

International Nuclear Information System (INIS)

Antwi-wiredu, A.

2015-07-01

The study was aimed at the propagation and molecular characterisation of some introduced clones of Hevea brasiliensis in Ghana. Propagation of H. brasiliensis by stem cuttings and in vitro techniques was used to study alternative procedures for mass production of rubber planting materials. Brown and green stem cuttings of Clone I and Clone II were soaked for 6 hours in 0.0-22.5g/L NAA followed by propagation in a nursery bag filled with nutrient-rich soil. Only the brown stem cuttings of H. brasiliensis survived. The % survival, length of shoots, number of roots as well as length of roots of Clone II was significantly (P<0.05) higher than Clone I. Stem cuttings treated with 15.0g/L NAA significantly (P<0.05) developed higher shoots (83.33%), number of roots (6.167), length of shoots (15.38cm) and length of roots (6.00cm) than the remaining treatments. There was significant (P<0.05) effects of NAA and Clone II in sprouting and rooting growth of the brown stem cuttings. The addition of 5.0mg/L kinetin in the MS culture medium significantly (P<0.05) enhanced higher shoot development (84.00%), number of shoots (3.60) and leaves (23.40) of the shoot-tip explants compared to other treatments. In nodal explants cultured on a medium without kinetin developed higher shoots (94.00%), height of shoot (4.80cm), number of leaves (19.20), number of shoots (6.00) and number of roots (7.00) than those with kinetin treatments. However, 7.5mg/L kinetin of the nodal culture also performed significantly after the controls. A dendrogram derived from the UPGMA distinguished the rubber clones from four areas of Ghana into two clusters. The five SSR markers showed high degree of relatedness among the rubber clones which suggested high genetic similarity (IRCA317-5, IRCA41-2, IRCA331-6, IRCA230-4, IRCA109-3, B8-23) and some degree of diversity/variation (K2-18,IRCA840-7, PB217-8, PB217-10, IRCA317-16) among the clones. Thus, clones of interest could be selected for future breeding and

Expression Profiling of Mitogen-Activated Protein Kinase Genes Reveals Their Evolutionary and Functional Diversity in Different Rubber Tree (Hevea brasiliensis Cultivars

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Xiang Jin

2017-10-01

Full Text Available Rubber tree (Hevea brasiliensis is the only commercially cultivated plant for producing natural rubber, one of the most essential industrial raw materials. Knowledge of the evolutionary and functional characteristics of kinases in H. brasiliensis is limited because of the long growth period and lack of well annotated genome information. Here, we reported mitogen-activated protein kinases in H. brasiliensis (HbMPKs by manually checking and correcting the rubber tree genome. Of the 20 identified HbMPKs, four members were validated by proteomic data. Protein motif and phylogenetic analyses classified these members into four known groups comprising Thr-Glu-Tyr (TEY and Thr-Asp-Tyr (TDY domains, respectively. Evolutionary and syntenic analyses suggested four duplication events: HbMPK3/HbMPK6, HbMPK8/HbMPK9/HbMPK15, HbMPK10/HbMPK12 and HbMPK11/HbMPK16/HbMPK19. Expression profiling of the identified HbMPKs in roots, stems, leaves and latex obtained from three cultivars with different latex yield ability revealed tissue- and variety-expression specificity of HbMPK paralogues. Gene expression patterns under osmotic, oxidative, salt and cold stresses, combined with cis-element distribution analyses, indicated different regulation patterns of HbMPK paralogues. Further, Ka/Ks and Tajima analyses suggested an accelerated evolutionary rate in paralogues HbMPK10/12. These results revealed HbMPKs have diverse functions in natural rubber biosynthesis, and highlighted the potential possibility of using MPKs to improve stress tolerance in future rubber tree breeding.

Rubber (Hevea brasiliensis) seed oil toxicity effect and Linamarin compound analysis.

Science.gov (United States)

Salimon, Jumat; Abdullah, Bashar Mudhaffar; Salih, Nadia

2012-06-13

The lipid fraction of rubber (Hevea brasiliensis (kunth. Muell)) seed was extracted and analyzed for toxicological effect. The toxicological compound such as linamarin in rubber seed oil (RSO) extracted using different solvents, such as hexane (RSOh), mixture of chloroform + methanol (RSOchl+mth) and ethanol (RSOeth) were also studied. Various methods analysis such as Fourier transforms infrared spectroscopy (FTIR) and colorimetric methods were carried out to determine the present of such compounds. FTIR spectrum of RSO did not show any presence of cyanide peak. The determination of cyanide by using colorimetric method was demonstrated no response of the cyanide in RSO and didn't show any colored comparing with commercial cyanide which observed blue color. The results showed that no functional groups such as cyanide (C ≡ N) associated with linamarin were observed. Toxicological test using rats was also conducted to further confirm the absence of such compounds. RSO did not show any toxic potential to the rats. Bioassay experiments using shrimps had been used as test organisms to evaluate the toxicity of linamarin extract from RSO(h,) RSO(chl+mth) and RSO(eth) and LC50 were found to be (211.70 %, 139.40 %, and 117.41 %, respectively). This can be attributed no hazardous linamarin were found in RSO.

Use of low energy accelerator for the radiation vulcanization of natural rubber latex and nitrile rubber. The battle for the sustainability and poverty alleviation

International Nuclear Information System (INIS)

Chirinos, Hugo D.; Lugao, Ademar B.

2001-01-01

The origin of the Hevea braziliensis tree was the Amazonian basin. The rubber expansion at the end of 19th century brought prosperity and determined the borders of Amazonian countries. In spite of that, the Brazilian government has failed in establishing a successful policy for improving the NR production in the jungle. This battle has been a continuous defeat against the environment as it was not possible to control the fungus Microcyclos ulei in its natural environment. The defeat was catastrophic for the population of Amazon region as they were not able to shift to other sustainable activity. As a consequence of the tack of economical options, the population had to explore all available natural resources. It has been also catastrophic for the Amazonian environment. Nevertheless, rubber plantations were successfully introduced in areas were Hevea braziliensis was not native, mainly in the southeast of Brazil. And recently, it was also introduced near marginal areas of the humid forest in the Amazon due to the absence of the fungus Microcyclos ulei. Both, extraction of wild rubber and plantation have a key role in the maintenance of the forest health as the seringueiros not only have a sustainable activity but can also play a role as soldiers of the jungle. Actually, rubber activities are not only associated to the environment but also with poverty because the activities are labor intensive, so it needs cheap labor. The poverty is unfortunately spread out in rural areas of Brazil and in the peripheral areas of the big cities. Regarding environment and poverty the dilemma is critical in the Amazonian region and is the following: the forest should be maintained healthy and protected from devastating projects and at the same time needs of the inhabitants should be considered. (author)

Neofusicoccum ribis Associated with Leaf Blight on Rubber (Hevea brasiliensis in Peninsular Malaysia

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A. I. C. Nyaka Ngobisa

2013-03-01

Full Text Available Hevea brasiliensis is a natural source of rubber and an important plantation tree species in Malaysia. Leaf blight disease caused by Fusicoccum substantially reduces the growth and performance of H. brasiliensis. The aim of this study was to use a combination of both morphological characteristics and molecular data to clarify the taxonomic position of the fungus associated with leaf blight disease. Fusicoccum species were isolated from infected leaves collected from plantations at 3 widely separated locations – Selangor, Perak, and Johor states – in Peninsular Malaysia in 2010. All the isolates were identified according to their conidial patterns and DNA sequences generated from internal transcribed spacers (ITS1 and ITS2, the 5.8S rRNA, and an unknown locus (BotF15 containing microsatellite repeats. Based on taxonomic and sequence data, Neofusicoccum ribis was identified as the main cause of leaf blight disease in H. brasiliensis in commercial plantations in Malaysia. A pathogenicity trial on detached leaves further confirmed that N. ribis causes leaf blight disease. N. ribis is an important leaf pathogen, and its detection in Malaysia has important implications for future planting of H. brasiliensis.

An overview of the potentials of natural rubber ( Hevea brasiliensis ...

African Journals Online (AJOL)

Tapping rubber trees for valuable proteins will be more profitable compared to other options. The technologies have been developed and only needs to be adapted to our local conditions. It is hoped that this paper will be instructive to rubber farmers, policy makers, executors of policies or citizens wishing to join the Nigerian ...

Rubber (Hevea brasiliensis seed oil toxicity effect and Linamarin compound analysis

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Salimon Jumat

2012-06-01

Full Text Available Abstract Background The lipid fraction of rubber (Hevea brasiliensis (kunth. Muell seed was extracted and analyzed for toxicological effect. The toxicological compound such as linamarin in rubber seed oil (RSO extracted using different solvents, such as hexane (RSOh, mixture of chloroform + methanol (RSOchl+mth and ethanol (RSOeth were also studied. Various methods analysis such as Fourier transforms infrared spectroscopy (FTIR and colorimetric methods were carried out to determine the present of such compounds. Results FTIR spectrum of RSO did not show any presence of cyanide peak. The determination of cyanide by using colorimetric method was demonstrated no response of the cyanide in RSO and didn’t show any colored comparing with commercial cyanide which observed blue color. The results showed that no functional groups such as cyanide (C ≡ N associated with linamarin were observed. Toxicological test using rats was also conducted to further confirm the absence of such compounds. RSO did not show any toxic potential to the rats. Bioassay experiments using shrimps had been used as test organisms to evaluate the toxicity of linamarin extract from RSOh, RSOchl+mth and RSOeth and LC50 were found to be (211.70 %, 139.40 %, and 117.41 %, respectively. Conclusions This can be attributed no hazardous linamarin were found in RSO.

Kinetic Study on Catalytic Cracking of Rubber Seed (Hevea brasiliensis Oil to Liquid Fuels

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Wara Dyah Pita Rengga

2015-03-01

Full Text Available Reaction kinetics of catalytic cracking of rubber seed oil to liquid fuels has been investigated. The reac-tion was performed with sulfuric acid as catalyst at temperatures of 350-450 oC and the ratio of oil-catalyst of 0-2 wt.% for 30-90 minutes. Kinetics was studied using the model of 6-lump parameters. The parameters were rubber seed oil, gasoline, kerosene, diesel, gas, and coke. Analysis of experimen-tal data using regression models to obtain reaction rate constants. Activation energies and pre-exponential factors were then calculated based on the Arrhenius equation. The simulation result illus-trated that the six-lump kinetic model can well predict the product yields of rubber seed oil catalytic cracking. The product has high selectivity for gasoline fraction as liquid fuel and the smallest amount of coke. The constant indicates that secondary reactions occurred in diesel products compared to gaso-line and kerosene. The predicted results indicate that catalytic cracking of rubber seed oil had better be conducted at 450 oC for 90 minutes using 0.5 wt.% catalyst. © 2015 BCREC UNDIP. All rights reservedReceived: 3rd December 2013; Revised: 5th December 2014; Accepted: 7th December 2014How to Cite: Rengga, W.D.P., Handayani, P.A., Kadarwati, S., Feinnudin, A.(2015. Kinetic Study on Catalytic Cracking of Rubber Seed (Hevea brasiliensis Oil  to Liquid Fuels. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (1: 50-60. (doi:10.9767/bcrec.10.1.5852.50-60Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.1.5852.50-60

Assessment of the genetic diversity of natural rubber tree clones of the SINCHI Institutes clone collection, using of morphological descriptors

International Nuclear Information System (INIS)

Quesada Mendez, Isaac; Quintero Barrera, Lorena; Aristizabal, Fabio A; Rodriguez Acuna, Olga

2011-01-01

Genetic diversity of natural rubber clones of the in SINCHI Institute’s clone collection was assessed. Clones of Hevea brasiliensis (Willd. ex Adr. De Juss.) Muell.Arg., Hevea spp. (H. brasiliensis x H. benthamiana), and three more species of Hevea genus are a part of the collection. Seventy-two materials were characterized with twenty-eight morphological descriptors. They were later used to generate a similarity matrix through the analysis of multi-categorical variables, and to obtain clusters based on the matrix. A low variability between clones of H. brasiliensis and H. spp. was observed, presumably because of the direct descendants of most of the materials from crosses of parental PB 80, PB 5/51, PB 49 and Tjir, exception made of clone GU 1410. Clustering between some materials product of exclusive cross of PB series, a group between clones descendants of parental clones PB 86, and clustering between descendants of parental clones PB 5/51, were observed. Clones from other species of Hevea differ from this big group.

Biological cycle of Tenuipalpus heveae Baker (Acari, Tenuipalpidae on leaflets of three rubber tree clones Ciclo de vida de Tenuipalpus heveae Baker (Acari, Tenuipalpidae em folíolos de três clones de seringueira

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Reinaldo José Fazzio Feres

2010-06-01

Full Text Available Life cycle of Tenuipalpus heveae Baker (Acari, Tenuipalpidae on leaflets from three rubber tree clones. The biological cycle of Tenuipalpus heveae Baker, 1945 (Tenuipalpidae, a potential rubber tree pest mite, was studied by the observation of individuals reared on leaflets of the clones GT 1, PB 235 and RRIM 600, in controlled environmental conditions. Three daily observations were done of 60 eggs on leaflets from each clone in order to verify the development of immature stages and the female oviposition. The fertility life table was constructed based in the collected data. Mites reared on PB 235 had faster rate of development, requiring less time in days, to double its population in number (TD, and had the highest values for egg production, female longevity, net reproductive rate (Ro, intrinsic rate of natural increase (r m and finite rate of increase (λ. Lower reproductive values and the longest time necessary to reach adult stage were recorded for the mites on GT 1. In all studied clones, the deutonymphal phase had the highest viability, while the larval phase had the lowest, highlighted by the survivorship curve that indicated high mortality during this life stage. The clone PB 235 allowed the most suitable conditions for the development of T. heveae, followed by RRIM 600, while GT 1 was the less suitable substratum to rear this mite species.O ciclo de vida de Tenuipalpus heveae Baker, 1945 (Tenuipalpidae, um potencial ácaro-praga da seringueira, foi estudado a partir de indivíduos criados sobre folíolos destacados dos clones GT 1, PB 235 e RRIM 600, em condições controladas. Três observações diárias foram realizadas, acompanhando-se o desenvolvimento de 60 ovos e de sua prole em folíolos de cada um dos clones, para verificação da oviposição das fêmeas e dos estágios de desenvolvimento. A partir dos dados obtidos, foi elaborada uma tabela de vida de fertilidade. Os ácaros criados sobre folíolos de PB 235 apresentaram r

A Lettuce (Lactuca sativa) Homolog of Human Nogo-B Receptor Interacts with cis-Prenyltransferase and Is Necessary for Natural Rubber Biosynthesis*

Science.gov (United States)

Qu, Yang; Chakrabarty, Romit; Tran, Hue T.; Kwon, Eun-Joo G.; Kwon, Moonhyuk; Nguyen, Trinh-Don; Ro, Dae-Kyun

2015-01-01

Natural rubber (cis-1,4-polyisoprene) is an indispensable biopolymer used to manufacture diverse consumer products. Although a major source of natural rubber is the rubber tree (Hevea brasiliensis), lettuce (Lactuca sativa) is also known to synthesize natural rubber. Here, we report that an unusual cis-prenyltransferase-like 2 (CPTL2) that lacks the conserved motifs of conventional cis-prenyltransferase is required for natural rubber biosynthesis in lettuce. CPTL2, identified from the lettuce rubber particle proteome, displays homology to a human NogoB receptor and is predominantly expressed in latex. Multiple transgenic lettuces expressing CPTL2-RNAi constructs showed that a decrease of CPTL2 transcripts (3–15% CPTL2 expression relative to controls) coincided with the reduction of natural rubber as low as 5%. We also identified a conventional cis-prenyltransferase 3 (CPT3), exclusively expressed in latex. In subcellular localization studies using fluorescent proteins, cytosolic CPT3 was relocalized to endoplasmic reticulum by co-occurrence of CPTL2 in tobacco and yeast at the log phase. Furthermore, yeast two-hybrid data showed that CPTL2 and CPT3 interact. Yeast microsomes containing CPTL2/CPT3 showed enhanced synthesis of short cis-polyisoprenes, but natural rubber could not be synthesized in vitro. Intriguingly, a homologous pair CPTL1/CPT1, which displays ubiquitous expressions in lettuce, showed a potent dolichol biosynthetic activity in vitro. Taken together, our data suggest that CPTL2 is a scaffolding protein that tethers CPT3 on endoplasmic reticulum and is necessary for natural rubber biosynthesis in planta, but yeast-expressed CPTL2 and CPT3 alone could not synthesize high molecular weight natural rubber in vitro. PMID:25477521

Análisis de la variación genética en clones de caucho (Hevea brasiliensis de Asia, Suramérica y Centroamérica usando marcadores RAPD Analysis of genetic variation in clones of rubber (Hevea brasiliensis from Asían, South and Central American origin using RAPDs markers

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Lobo Arias Mario

2006-12-01

Full Text Available El caucho natural (Hevea brasiliensis representa a especies potenciales para reforestación y programas de explo­tación comercial en ciudades tropicales como Colombia. La variabilidad genética de una colección de caucho que se encuentra en la Estación experimental de Paraguaycito en Buenavista, departamento del Quindio en Colom­bia fue estudiada para aumentar el conocimiento en cuanto a las especies y realizar un mejor uso de los árboles disponibles. Un total de 25 clones, seis de Sur América, 17 de Asia y 2 de América Central fueron seleccionados y analizados usando RAPDs. Las muestras aisladas de ADN de los árboles fueron con 102 primers, 23 de los cuales mostraron polimorfismos. Aunque se encontró un alto grado de similaridad, los análisis grupales de datos llevaron a diferenciar los árboles de de caucho en términos de su origen geográfico. Por lo tanto, las relaciones genéticas que se encontraron entre los clones podrían ayudar a seleccionar parentales para uso en programas de reproducción y diseño de estrategias para la conservación de los clones que tengan características agronómicas deseables. Palabras clave: identificación de cultivos, distancia genética, diversidad genética, Hevea brasiliensis, marcadores RAPD.Rubber (Hevea brasiliensis represents a potential species for reforestation and commercial exploitation programmes in tropical countries such as Colombia. The genetic variability of a rubber collection kept at the Paraguaicito Experimental Station in Buenavista in the Quindio department of Colombia was studied to improve knowledge regarding this species and make better use of the trees available. A total of 25 clones, six from South-America, 17 from Asia and two from Central-América were selected and analysed using RAPDs. DNA samples isolated from the trees were screened with 102 primers, 23 of which revealed polymorphism. Although a high degree of similarity was found, clustering analysis of the data led

Ciprofloxacin release using natural rubber latex membranes as carrier.

Science.gov (United States)

Dias Murbach, Heitor; Jaques Ogawa, Guilherme; Azevedo Borges, Felipe; Romeiro Miranda, Matheus Carlos; Lopes, Rute; Roberto de Barros, Natan; Guedes Mazalli, Alexandre Vinicius; Gonçalves da Silva, Rosângela; Ferreira Cinman, José Luiz; de Camargo Drago, Bruno; Donizetti Herculano, Rondinelli

2014-01-01

Natural rubber latex (NRL) from Hevea brasiliensis is easily manipulated, low cost, is of can stimulate natural angiogenesis and cellular adhesion, is a biocompatible, material and presents high mechanical resistance. Ciprofloxacin (CIP) is a synthetic antibiotic (fluoroquinolone) used in the treatment of infection at external fixation screws sites and remote infections, and this use is increasingly frequent in medical practice. The aim of this study was to develop a novel sustained delivery system for CIP based on NRL membranes and to study its delivery system behavior. CIP was found to be adsorbed on the NRL membrane, according to results of energy dispersive X-ray spectroscopy. Results show that the membrane can release CIP for up to 59.08% in 312 hours and the mechanism is due to super case II (non-Fickian). The kinetics of the drug release could be fitted with double exponential function X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy shows some interaction by hydrogen bound, which influences its mechanical behavior.

Evaluation of peptides release using a natural rubber latex biomembrane as a carrier.

Science.gov (United States)

Miranda, M C R; Borges, F A; Barros, N R; Santos Filho, N A; Mendonça, R J; Herculano, R D; Cilli, E M

2018-05-01

The biomembrane natural (NRL-Natural Rubber Latex), manipulated from the latex obtained from the rubber tree Hevea brasiliensis, has shown great potential for application in biomedicine and biomaterials. Reflecting the biocompatibility and low bounce rate of this material, NRL has been used as a physical barrier to infectious agents and for the controlled release of drugs and extracts. The aim of the present study was to evaluate the incorporation and release of peptides using a latex biomembrane carrier. After incorporation, the release of material from the membrane was observed using spectrophotometry. Analyses using HPLC and mass spectroscopy did not confirm the release of the antimicrobial peptide [W 6 ]Hylin a1 after 24 h. In addition, analysis of the release solution showed new compounds, indicating the degradation of the peptide by enzymes contained in the latex. Additionally, the release of a peptide with a shorter sequence (Ac-WAAAA) was evaluated, and degradation was not observed. These results showed that the use of NRL as solid matrices as delivery systems of peptide are sequence dependent and could to be evaluated for each sequence.

Comparative Transcriptome Analysis of Latex Reveals Molecular Mechanisms Underlying Increased Rubber Yield in Hevea brasiliensis Self-Rooting Juvenile Clones.

Science.gov (United States)

Li, Hui-Liang; Guo, Dong; Zhu, Jia-Hong; Wang, Ying; Chen, Xiong-Ting; Peng, Shi-Qing

2016-01-01

Rubber tree (Hevea brasiliensis) self-rooting juvenile clones (JCs) are promising planting materials for rubber production. In a comparative trial between self-rooting JCs and donor clones (DCs), self-rooting JCs exhibited better performance in rubber yield. To study the molecular mechanism associated with higher rubber yield in self-rooting JCs, we sequenced and comparatively analyzed the latex of rubber tree self-rooting JCs and DCs at the transcriptome level. Total raw reads of 34,632,012 and 35,913,020 bp were obtained from the library of self-rooting JCs and DCs, respectively, by using Illumina HiSeq 2000 sequencing technology. De novo assemblies yielded 54689 unigenes from the library of self-rooting JCs and DCs. Among 54689 genes, 1716 genes were identified as differentially expressed between self-rooting JCs and DCs via comparative transcript profiling. Functional analysis showed that the genes related to the mass of categories were differentially enriched between the two clones. Several genes involved in carbohydrate metabolism, hormone metabolism and reactive oxygen species scavenging were up-regulated in self-rooting JCs, suggesting that the self-rooting JCs provide sufficient molecular basis for the increased rubber yielding, especially in the aspects of improved latex metabolisms and latex flow. Some genes encoding epigenetic modification enzymes were also differentially expressed between self-rooting JCs and DCs. Epigenetic modifications may lead to gene differential expression between self-rooting JCs and DCs. These data will provide new cues to understand the molecular mechanism underlying the improved rubber yield of H. brasiliensis self-rooting clones.

Finite Element Analysis of Simple Rectangular Microstrip Sensor for Determination Moisture Content of Hevea Rubber Latex

Science.gov (United States)

Yahaya, NZ; Ramli, MR; Razak, NNANA; Abbas, Z.

2018-04-01

The Finite Element Method, FEM has been successfully used to model a simple rectangular microstrip sensor to determine the moisture content of Hevea rubber latex. The FEM simulation of sensor and samples was implemented by using COMSOL Multiphysics software. The simulation includes the calculation of magnitude and phase of reflection coefficient and was compared to analytical method. The results show a good agreement in finding the magnitude and phase of reflection coefficient when compared with analytical results. Field distributions of both the unloaded sensor as well as the sensor loaded with different percentages of moisture content were visualized using FEM in conjunction with COMSOL software. The higher the amount of moisture content in the sample the more the electric loops were observed.

A lettuce (Lactuca sativa) homolog of human Nogo-B receptor interacts with cis-prenyltransferase and is necessary for natural rubber biosynthesis.

Science.gov (United States)

Qu, Yang; Chakrabarty, Romit; Tran, Hue T; Kwon, Eun-Joo G; Kwon, Moonhyuk; Nguyen, Trinh-Don; Ro, Dae-Kyun

2015-01-23

Natural rubber (cis-1,4-polyisoprene) is an indispensable biopolymer used to manufacture diverse consumer products. Although a major source of natural rubber is the rubber tree (Hevea brasiliensis), lettuce (Lactuca sativa) is also known to synthesize natural rubber. Here, we report that an unusual cis-prenyltransferase-like 2 (CPTL2) that lacks the conserved motifs of conventional cis-prenyltransferase is required for natural rubber biosynthesis in lettuce. CPTL2, identified from the lettuce rubber particle proteome, displays homology to a human NogoB receptor and is predominantly expressed in latex. Multiple transgenic lettuces expressing CPTL2-RNAi constructs showed that a decrease of CPTL2 transcripts (3-15% CPTL2 expression relative to controls) coincided with the reduction of natural rubber as low as 5%. We also identified a conventional cis-prenyltransferase 3 (CPT3), exclusively expressed in latex. In subcellular localization studies using fluorescent proteins, cytosolic CPT3 was relocalized to endoplasmic reticulum by co-occurrence of CPTL2 in tobacco and yeast at the log phase. Furthermore, yeast two-hybrid data showed that CPTL2 and CPT3 interact. Yeast microsomes containing CPTL2/CPT3 showed enhanced synthesis of short cis-polyisoprenes, but natural rubber could not be synthesized in vitro. Intriguingly, a homologous pair CPTL1/CPT1, which displays ubiquitous expressions in lettuce, showed a potent dolichol biosynthetic activity in vitro. Taken together, our data suggest that CPTL2 is a scaffolding protein that tethers CPT3 on endoplasmic reticulum and is necessary for natural rubber biosynthesis in planta, but yeast-expressed CPTL2 and CPT3 alone could not synthesize high molecular weight natural rubber in vitro. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

PROBLEMATIC IN THE PROCESSES OF PRODUCTION IN RUBBER PLANTATIONS (Hevea brasiliensis Muell Arg. IN TABASCO, MEXICO

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Heyra Izquierdo-Bautista

2011-03-01

Full Text Available The objective of this study was to identify some of the basic problems presented in the production process in rubber plantations Hevea brasiliensis Muell Arg. in Tabasco, Mexico. The applied diagnosis technique was the randomized survey for 68 producers in plantations under rubber production. ANOVA and Duncan analyses were done (P< 0.05. Plantations under production were between 7 to 46 years old. The 24% of these are considered as young plantations (7 to 18 years old, 34% mature (19 to 30 years old, and 12% old growth (31 to 46 years old, according to the level of latex production. Latex collection is realized by 85% men and 15% women. An important detected problem is the incidence of insects and diseases over the 82% of the plantations. In Tabasco State, two types of raw material are generated: clot (solid and latex (liquid. The tapping systems are ½ S d/1 6d/7 (one cuts in an average spiral with daily tapping over the 49% of the plantations, and the system ½ S d/2 6d/7, cuts in semi-spirals with alternating tapping over 51% of the plantations. The producers that practiced daily tapped obtained yields of 1.588 kg per ha/yr of dry rubber, in the other hand, those that tapped every other day obtained a yield of 1.647 kg per ha/year of dry rubber. The yield in daily tapping was 3.54% lower than the system with alternating tapping. The income obtained by the producers of fresh rubber varied from $8.750, 00 (810, 2 USD ha/year to $27.870, 00 (2.580 USD ha/year in 2006 and the production of latex from $5.955, 00 (551, 4 USD to 16.568,00 (1.534 USD per ha/year.

Nano-reinforcement of tire rubbers: silica-technology for natural rubber : exploring the infuence of non-rubber constituents on the natural rubber-silica system

NARCIS (Netherlands)

Sarkawi, S.S.

2013-01-01

Natural rubber is a renewable resource material with outstanding properties which offers significant advantages over its counterparts, the fossil-resource synthetic rubbers. In fact, a natural rubber tree is an efficient carbon dioxide sequester. Since natural rubber is a natural product, it is

Natural rubber latex: past, present and future in Latin America

International Nuclear Information System (INIS)

Lugao, A.B.; Miranda, A.; Mindrisz, A.C.; Andrade e Silva, L.G. de

1996-01-01

The origin of the Hevea braziliensis tree was the Amazonian region in South America, particularly the Brazilian jungle. The rubber expansion at the end of 9th century brought prosperity and determined the borders of Amazonian countries. In spite of that, the Brazilian government has failed in establishing a successful policy for improving the NR production in the jungle. However, rubber plantations were successfully introduced recently near marginal areas of the humid forest in the Amazon due to the absence of the fungus Microcyclos ulei. Both, extraction of wild rubber and plantation have a key role in the maintenance of the forest health. The market for dipping products is small but is growing very fast and is expected to follow this pattern as the sanitary conditions are improved by the health authority. The history of the Brazilian NR products industry is contemporary and is based on the policy of market protection and on the lack of investments due to extremely high interest rates. As a result, the industry was not competitive. It was concluded that, in order to cope with the future challenge, the industry is required to invest in very modern technologies to produce first class goods with international acceptance. Latin America would follow the world trend for nitrosamine and protein free products. The radiation vulcanization of natural rubber latex could prove itself as a profitable solution and not only a quality solution. It was also concluded that both wild rubber and rubber plantations in Brazil have their future coupled with the future of a regional dipping industry. Moreover, the buildup of the dipping industry will be beneficial to the protection of the humid forest and the recovery of degraded areas

Diclofenac Potassium Transdermal Patches Using Natural Rubber Latex Biomembranes as Carrier

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Natan Roberto de Barros

2015-01-01

Full Text Available The aim of this study was to design a compound transdermal patch containing diclofenac potassium (Dic-K using natural rubber latex (NRL biomembrane. The NRL from Hevea brasiliensis is easily manipulated and low cost and presents high mechanical resistance. It is a biocompatible material which can stimulate natural angiogenesis and is capable of adhering cells on its surface. Recent researches have used the NRL for Transdermal Drug Delivery Systems (TDDSs. Dic-K is used for the treatment of rheumatoid arthritis and osteoarthritis and pain relief for postoperative and posttraumatic cases, as well as inflammation and edema. Results showed that the biomembrane can release Dic-K for up to 216 hours. The kinetics of the Dic-K release could be fitted with double exponential function. X-ray diffraction and Fourier Transform Infrared (FTIR spectroscopy show some interaction by hydrogen bound. The results indicated the potential of the compound patch.

Hevamine, a chitinase from the rubber tree Hevea brasiliensis, cleaves peptidoglycan between the C-1 of N-acetylglucosamine and C-4 of N-acetylmuramic acid and therefore is not a lysozyme

NARCIS (Netherlands)

Bokma, E; vanKoningsveld, GA; JeronimusStratingh, M; Beintema, JJ

1997-01-01

Hevamine is a chitinase from the rubber tree Hevea brasiliensis and belongs to the family 18 glycosyl hydrolases. In this paper the cleavage specificity of hevamine for peptidoglycan was studied by HPLC and mass-spectrometry analysis of enzymatic digests. The results clearly showed that the enzyme

Cultura experimental de seringueira (Hevea brasiliensis Muell.-arg. na fazenda "unidas do sul", em Juquiá Experimental results from a rubber planting at the coast of the state of São Paulo

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João Ferreira da Cunha

1963-01-01

Full Text Available São apresentados os resultados do estudo do plantio de seringueiras (Hevea brasiliensis Muell.-Arg. Tj-1 x Tj-16, com o fim de pesquisar a adaptação dessa planta ao ambiente situado a 24°10' de latitude sul, no litoral do Estado de São Paulo, a baixa altitude e próximo da Serra do Mar. A plantação é uma das primeiras da região, tendo demonstrado regular desenvolvimento das árvores. A produção de borracha obtida pelo teste Morris-Mann não foi elevada, presumindo-se que a falta de tratos culturais oportunamente dispensados tivesse exercido influência desfavorável sôbre o crescimento normal das plantas e rendimento na produtividade.This paper reports on the results obtained in an experimental planting of Hevea rubber (H. brasiliensis Muell.-Arg. made with the Tj-1 X Tj-16 hybrid at Fazendas Unidas do Sul, Juquiá, São Paulo. This planting was made to test the adaptability of the Hevea plant to a low elevation area near the Serra do Mar range, located at 24°10' south. Growth of the Hevea plants in this experimental planting was fair, but yield data obtained by means of the Morris-Mann test indicated that it was rather low. The unsatisfactory growth as well as the poor yield are attributed to the poor handling of the rubber planting rather than to an unfavorable effect of the environment.

Characterization of Sugar Contents and Sucrose Metabolizing Enzymes in Developing Leaves of Hevea brasiliensis

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Jinheng Zhu

2018-02-01

Full Text Available Sucrose-metabolizing enzymes in plant leaves have hitherto been investigated mainly in temperate plants, and rarely conducted in tandem with gene expression and sugar analysis. Here, we investigated the sugar content, gene expression, and the activity of sucrose-metabolizing enzymes in the leaves of Hevea brasiliensis, a tropical tree widely cultivated for natural rubber. Sucrose, fructose and glucose were the major sugars detected in Hevea leaves at four developmental stages (I to IV, with starch and quebrachitol as minor saccharides. Fructose and glucose contents increased until stage III, but decreased strongly at stage IV (mature leaves. On the other hand, sucrose increased continuously throughout leaf development. Activities of all sucrose-cleaving enzymes decreased markedly at maturation, consistent with transcript decline for most of their encoding genes. Activity of sucrose phosphate synthase (SPS was low in spite of its high transcript levels at maturation. Hence, the high sucrose content in mature leaves was not due to increased sucrose-synthesizing activity, but more to the decline in sucrose cleavage. Gene expression and activities of sucrose-metabolizing enzymes in Hevea leaves showed striking differences compared with other plants. Unlike in most other species where vacuolar invertase predominates in sucrose cleavage in developing leaves, cytoplasmic invertase and sucrose synthase (cleavage direction also featured prominently in Hevea. Whereas SPS is normally responsible for sucrose synthesis in plant leaves, sucrose synthase (synthesis direction was comparable or higher than that of SPS in Hevea leaves. Mature Hevea leaves had an unusually high sucrose:starch ratio of about 11, the highest reported to date in plants.

Identification of Powdery Mildew Responsive Genes in Hevea brasiliensis through mRNA Differential Display

Science.gov (United States)

Li, Xiang; Bi, Zhenghong; Di, Rong; Liang, Peng; He, Qiguang; Liu, Wenbo; Miao, Weiguo; Zheng, Fucong

2016-01-01

Powdery mildew is an important disease of rubber trees caused by Oidium heveae B. A. Steinmann. As far as we know, none of the resistance genes related to powdery mildew have been isolated from the rubber tree. There is little information available at the molecular level regarding how a rubber tree develops defense mechanisms against this pathogen. We have studied rubber tree mRNA transcripts from the resistant RRIC52 cultivar by differential display analysis. Leaves inoculated with the spores of O. heveae were collected from 0 to 120 hpi in order to identify pathogen-regulated genes at different infection stages. We identified 78 rubber tree genes that were differentially expressed during the plant–pathogen interaction. BLAST analysis for these 78 ESTs classified them into seven functional groups: cell wall and membrane pathways, transcription factor and regulatory proteins, transporters, signal transduction, phytoalexin biosynthesis, other metabolism functions, and unknown functions. The gene expression for eight of these genes was validated by qRT-PCR in both RRIC52 and the partially susceptible Reyan 7-33-97 cultivars, revealing the similar or differential changes of gene expressions between these two cultivars. This study has improved our overall understanding of the molecular mechanisms of rubber tree resistance to powdery mildew. PMID:26840302

CDNA library from the Latex of Hevea brasiliensis

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Wilaiwan Chotigeat

2010-12-01

Full Text Available Latex from Hevea brasiliensis contains 30-50% (w/w of natural rubber (cis-1,4-polyisoprene, the important rawmaterial for many rubber industries. We have constructed a cDNA library from the latex of H. brasiliensis to investigate theexpressed genes and molecular events in the latex. We analyzed 412 expressed sequence tags (ESTs. More than 90% of theEST clones showed homology to previously described sequences in public databases. Functional classification of the ESTsshowed that the largest category were proteins of unknown function (30.1%, 11.4% of ESTs encoded for rubber synthesisrelatedproteins (RS and 8.5% for defense or stress related proteins (DS. Those with no significant homology to knownsequences (NSH accounted for 8.7%, primary metabolism (PM and gene expression and RNA metabolism were 7.8% and6.6%, respectively. Other categories included, protein synthesis-related proteins (6.6%, chromatin and DNA metabolism(CDM 3.9%, energy metabolism (EM 3.4%, cellular transport (CT 3.2%, cell structure (CS 3.2%, signal transduction (ST2.2%, secondary metabolism (SM 1.7%, protein fate (PF 2.2%, and reproductive proteins (RP 0.7%.

A review of the Mycrocylus ulei Ascomycetes fungus, causative agent of South American rubber-leaf blight

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Ibonne Aydee García-Romero

2006-07-01

Full Text Available The Microcyclus ulei Ascomycetes fungus is the causal agent of south-American leaf blight (SALB, this being one of the most important diseases affecting the natural rubber tree (Hevea brasiliensis in Latina-America and has been responsible for numerous economic losses. This fungus has presented high physiological variability, suggesting its great adaptability. HCN tolerance has been described as being one of the mechanisms associated with its virulence. Resistant Hevea clones have been obtained by genetic improvement; however, the mechanisms associated with this are still not well known. Greater knowledge of this pathogen will lead to developing new control strategies and better understanding of the mechanisms associated with host resistance. Key words: Microcyclus ulei, SALB, Hevea brasiliensis.

Natural rubber: leather composites

OpenAIRE

Ravichandran,K.; Natchimuthu,N.

2005-01-01

Leather is a fibrous protein consisting of collagen in a three dimensionally crosslinked network. Chrome tanning of leather improves the appearance of leather but at the same time emits both solid and liquid chrome leather wastes. Scrap rubber recycling using untreated and neutralized leather fibrous particles in natural rubber has been studied. Vulcanization, mechanical, morphological and swelling properties of the natural rubber - scrap rubber composites containing neutralized leather have ...

POTENTIAL OF CARBON STORAGE OF RUBBER (Hevea brasiliensis MÃœLL. ARG. PLANTATIONS IN MONOCULTURE AND AGROFORESTRY SYSTEMS IN THE COLOMBIAN AMAZON

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Hernán Jair Andrade

2014-08-01

Full Text Available Carbon sequestration potential of rubber (Hevea brasiliensis plantations was estimated in two production systems: monoculture and agroforestry system with copoazú (Theobroma grandiflorum, on farms of Florencia, El Doncello and Belén de los Andaquíes, in northeastern Colombian Amazon, department of Caquetá. The plantations were classified into three age classes, according to their productive stage: 1-7, 8-20 and > 20 years. The carbon storage was estimated using the methodology proposed by Andrade and Ibrahim (2003 and recommended by IPCC (2003. Tree carbon sinks were evaluated: above and below ground biomass, and necromass. The highest proportion of carbon storage was found in biomass, with 95 and 92% in monoculture plantations and agroforestry systems, respectively. In both types of production systems, carbon storage is a function of tree age and density. The carbon stored in monoculture plantations was higher than in agroforestry systems, due to a greater density of rubber trees in the first production system. This study confirms that rubber plantations have potential to capture and store atmospheric carbon. With this information, the issue of participating in carbon markets of the rubber production chain can be addressed, and therefore strengthen in the region’s competitiveness and sustainability.

Natural rubber: leather composites

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K. Ravichandran

2005-06-01

Full Text Available Leather is a fibrous protein consisting of collagen in a three dimensionally crosslinked network. Chrome tanning of leather improves the appearance of leather but at the same time emits both solid and liquid chrome leather wastes. Scrap rubber recycling using untreated and neutralized leather fibrous particles in natural rubber has been studied. Vulcanization, mechanical, morphological and swelling properties of the natural rubber - scrap rubber composites containing neutralized leather have been discussed. Use of chrome leather particles has been found to improve the consumption of scrap rubber powder in natural rubber formulations. Polymer composites based on leather wastes as fillers are reported to be useful for many applications such as in construction materials, automobile interior moldings, heat and sound insulating boards, shoe soles, flooring materials and moldings with good anti-static properties, air permeability and good appearances.

Electrospinning of PVC with natural rubber

Science.gov (United States)

Othman, Muhammad Hariz; Mohamed, Mahathir; Abdullah, Ibrahim

2013-11-01

Polyvinyl chloride (PVC) was mixed with natural rubbers which are liquid natural rubber (LNR), liquid epoxidised natural rubber (LENR) and liquid epoxidised natural rubber acrylate (LENRA) for a preparation of a fine non-woven fiber's mat. PVC and each natural rubbers(PVC:LENR, PVC:LNR and PVC:LENRA) were mixed based on ratio of 70:30. Electrospinning method was used to prepare the fiber. The results show that the spinnable concentration of PVC/ natural rubber/THF solution is 16 wt%. The morphology, diameter, structure and degradation temperature of electrospun fibers were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM photos showed that the morphology and diameter of the fibers were mainly affected by the addition of natural rubber. TGA results suggested that PVC electrospun fiber has higher degradation temperature than those electrospun fibers that contain natural rubber.

Electrospinning of PVC with natural rubber

International Nuclear Information System (INIS)

Othman, Muhammad Hariz; Abdullah, Ibrahim; Mohamed, Mahathir

2013-01-01

Polyvinyl chloride (PVC) was mixed with natural rubbers which are liquid natural rubber (LNR), liquid epoxidised natural rubber (LENR) and liquid epoxidised natural rubber acrylate (LENRA) for a preparation of a fine non-woven fiber’s mat. PVC and each natural rubbers(PVC:LENR, PVC:LNR and PVC:LENRA) were mixed based on ratio of 70:30. Electrospinning method was used to prepare the fiber. The results show that the spinnable concentration of PVC/ natural rubber/THF solution is 16 wt%. The morphology, diameter, structure and degradation temperature of electrospun fibers were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM photos showed that the morphology and diameter of the fibers were mainly affected by the addition of natural rubber. TGA results suggested that PVC electrospun fiber has higher degradation temperature than those electrospun fibers that contain natural rubber

Electrospinning of PVC with natural rubber

Energy Technology Data Exchange (ETDEWEB)

Othman, Muhammad Hariz; Abdullah, Ibrahim [Department of Chemistry, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Mohamed, Mahathir [Radiation Processing Technology Division (BTS), Malaysian Nuclear Agency, Bangi, 43000, Kajang (Malaysia)

2013-11-27

Polyvinyl chloride (PVC) was mixed with natural rubbers which are liquid natural rubber (LNR), liquid epoxidised natural rubber (LENR) and liquid epoxidised natural rubber acrylate (LENRA) for a preparation of a fine non-woven fiber’s mat. PVC and each natural rubbers(PVC:LENR, PVC:LNR and PVC:LENRA) were mixed based on ratio of 70:30. Electrospinning method was used to prepare the fiber. The results show that the spinnable concentration of PVC/ natural rubber/THF solution is 16 wt%. The morphology, diameter, structure and degradation temperature of electrospun fibers were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM photos showed that the morphology and diameter of the fibers were mainly affected by the addition of natural rubber. TGA results suggested that PVC electrospun fiber has higher degradation temperature than those electrospun fibers that contain natural rubber.

Production of Particleboards from Hevea brasiliensis Clones and Castor Oil-based Polyurethane Resin

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Maristela Gava

2015-08-01

Full Text Available The economic exploitation of rubber tree (Hevea brasiliensis usage is primarily directed toward latex extraction. After the productive life of the rubber tree forest, the managed area is harvested for planting reformulation. The harvested wood is most often used for energy generation purposes. The aim of this work was to study the feasibility of using rubberwood waste and castor oil-based polyurethane resin in the production of particleboards. Homogeneous and heterogeneous panels were made with nominal dimensions of 500 x 500 mm and thicknesses of 10 mm using particles from GT1 and RRIM600 clones of the rubber tree and 12% castor oil-based polyurethane adhesive. The panels were pressed at 140 °C for 12 min with 40 kgf/cm2 specific pressure. Density, moisture content, thickness swelling, water absorption for 2 and 24 h, static bending, and internal bonding determinations were performed according to the Brazilian Standard (NBR 14810-3 (2006 for the physical-mechanical panel characterization. The results show that using Hevea brasiliensis in particleboard production is viable. However, multilayer boards exhibited better results.

The Effect of Gamma Irradiation on the Mechanical Properties of vulcanized Natural Rubber and Natural Rubber-Polyethylene Blends

International Nuclear Information System (INIS)

Sudradjat Iskandar

2008-01-01

To enhance the quality of vulcanized natural rubber and natural rubber-polyethylene blends, gamma irradiation has been done. The compound of natural rubber and natural rubber-polyethylene blends made by using roll mill machine. The mixed materials were antioxidant, anti ozon, plasticizer and vulcanisator. The natural rubber and natural rubber-polyethylene blends compound were vulcanizer and made a slab (film of sample) using hot and could press machine. The slabs produced were then gamma irradiated at irradiation dose of 75, 150 and 300 kGy. Before and after irradiation, the slab were characterized using strograph R1 machine. The results showed that the modulus 300 and hardness of vulcanized natural rubber and natural rubber-polyethylene blends were increasing; the tensile strength and tear strength were increasing to maximum level then decreasing with gamma irradiation, while the elongation at break was decreasing. The maximum tensile strength of vulcanized natural rubber and natural rubber-polyethylene blends were found at irradiation dose of 75 kGy. At the irradiation dose of 75 kGy, the tensile strength of vulcanized natural rubber increased from 17.6 MN/m 2 to 21.2 MN/m 2 , while the tensile strength of vulcanized natural rubber-polyethylene blends increased slightly from 18.7 MN/m 2 to 19.4 MN/m 2 . (author)

Taxonomic revision and phylogenetic analyses of rubber powdery mildew fungi.

Science.gov (United States)

Liyanage, K K; Khan, Sehroon; Brooks, Siraprapa; Mortimer, Peter E; Karunarathna, Samantha C; Xu, Jianchu; Hyde, Kevin D

2017-04-01

Powdery mildew is a fungal disease that infects a wide range of plants, including rubber trees, which results in a reduction of latex yields of up to 45%. The causal agent of powdery mildew of rubber was first described as Oidium heveae, but later morpho-molecular research suggested that in the past, O. heveae has been confused with Erysiphe quercicola. However, it is still under debate whether the causal agent should be classified as a species of the genus Erysiphe emend. or Golovinomyces and Podosphaera, respectively. Therefore, the aim of this study was to undertake the morpho-molecular characterization of powdery mildew species associated with rubber trees, thus resolving these taxonomic issues. Morphological observation under light and scanning electron microscopes (SEM) clearly identified two morphotypes of the rubber powdery mildew. With the support of morphological and phylogenetic data, one of the two morphotypes was identified as the asexual morph of E. quercicola, while the second morphotype is still insufficiently known and according to the morphological results obtained we assume that it might belong to the genus Golovinomyces. More collections and additional molecular data are required for final conclusions regarding the exact taxonomic position of the second morphotype of rubber powdery mildew and its relation to the name O. heveae. The haplotype analysis identified eight haplotype groups of E. quercicola indicating the high genetic diversity of the species. Copyright © 2017 Elsevier Ltd. All rights reserved.

Intercomparison of Methods for Determination of Resonant Frequency Shift of a Microstrip Patch Antenna Loaded with Hevea Rubber Latex

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Nor Zakiah Yahaya

2014-01-01

Full Text Available This paper presents an intercomparison between the finite element method, method of moment, and the variational method to determine the effect of moisture content on the resonant frequency shift of a microstrip patch loaded with wet material. The samples selected for this study were Hevea rubber latex with different percentages of moisture content from 35% to 85%. The results were compared with the measurement data in the frequency range between 1 GHz and 4 GHz. It was found that the finite element method is the most accurate among all the three computational techniques with 0.1 mean error when compared to the measured resonant frequency shift. A calibration equation was obtained to predict moisture content from the measured frequency shift with an accuracy of 2%.

Simulation of Canopy CO2/H2O Fluxes for a Rubber (Hevea Brasiliensis) Plantation in Central Cambodia: The Effect of the Regular Spacing of Planted Trees

Energy Technology Data Exchange (ETDEWEB)

Kumagai, Tomo' omi; Mudd, Ryan; Miyazawa, Yoshiyuki; Liu, Wen; Giambelluca, Thomas; Kobayashi, N.; Lim, Tiva Khan; Jomura, Mayuko; Matsumoto, Kazuho; Huang, Maoyi; Chen, Qi; Ziegler, Alan; Yin, Song

2013-09-10

We developed a soil-vegetation-atmosphere transfer (SVAT) model applicable to simulating CO2 and H2O fluxes from the canopies of rubber plantations, which are characterized by distinct canopy clumping produced by regular spacing of plantation trees. Rubber (Hevea brasiliensis Müll. Arg.) plantations, which are rapidly expanding into both climatically optimal and sub-optimal environments throughout mainland Southeast Asia, potentially change the partitioning of water, energy, and carbon at multiple scales, compared with traditional land covers it is replacing. Describing the biosphere-atmosphere exchange in rubber plantations via SVAT modeling is therefore essential to understanding the impacts on environmental processes. The regular spacing of plantation trees creates a peculiar canopy structure that is not well represented in most SVAT models, which generally assumes a non-uniform spacing of vegetation. Herein we develop a SVAT model applicable to rubber plantation and an evaluation method for its canopy structure, and examine how the peculiar canopy structure of rubber plantations affects canopy CO2 and H2O exchanges. Model results are compared with measurements collected at a field site in central Cambodia. Our findings suggest that it is crucial to account for intensive canopy clumping in order to reproduce observed rubber plantation fluxes. These results suggest a potentially optimal spacing of rubber trees to produce high productivity and water use efficiency.

Crystallization of Hevamine, an Enzyme with Lysozyme/Chitinase Activity from Hevea brasiliensis Latex

NARCIS (Netherlands)

ROZEBOOM, HJ; BUDIANI, A; BEINTEMA, JJ

1990-01-01

Hevamine, an enzyme with both lysozyme and chitinase activity, was isolated and purified from Hevea brasiliensis (rubber tree) latex. The enzyme (molecular weight 29,000) is homologous to certain “pathogenesis-related” proteins from plants, but not to hen egg-white or phage T4 lysozyme. To

Karakteristik Pembakaran Biobriket Kulit dan Cangkang Karet (Hevea Brasiliensis) dengan Perekat Glyserin

OpenAIRE

I Wayan Wawan Mariki; Slamet Wahyudi; Denny Widhiyanuriyawan

2017-01-01

Some studies have been done on utilizing biomass from agriculture such as the leather and shell of rubber (Hevea brasiliensis) were not used optimally in Indonesia as an alternative energy which developed by making biobriquet to achieved the higher energy that could be used in the combustion process. In this study, the biobriquet was made of the leather and the shell of rubber by comparisson of the leather and shell were: 0%: 91%; 45.5%: 45.5%; 55%: 36%; 64%: 27%; 91%: 0%.Glyserin 9% for each...

Karakteristik Pembakaran Biobriket Kulit Dan Cangkang Karet (Hevea Brasiliensis) Dengan Perekat Glyserin

OpenAIRE

Mariki, I Wayan Wawan; Wahyudi, Slamet; Widhiyanuriyawan, Denny

2017-01-01

Some studies have been done on utilizing biomass from agriculture such as the leather and shell of rubber (Hevea Brasiliensis) were not used optimally in Indonesia as an alternative energy which developed by making biobriquet to achieved the higher energy that could be used in the combustion process. In this study, the biobriquet was made of the leather and the shell of rubber by comparisson of the leather and shell were: 0%: 91%; 45.5%: 45.5%; 55%: 36%; 64%: 27%; 91%: 0%.Glyserin 9% for each...

Premilinary studies for optimiziing a protocol for obtaining embryogenic calluses in two rubber (Hevea brasiliensis Mull. Arg clones from different geographical origins

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Santiago Cadavid Ruiz

2006-01-01

Full Text Available The influence of growth regulators on obtaining friable rubber (Hevea brasiliensis Müll. Arg. calluses with no plant regeneration as investigated. Two clones having different geographical origin were used in all trails carried out in this study: FX 3864 (South-American and PB 254 (Asian. Young leaves and eight- to ten-week-old seed integument from both clones were used as explants in several experiments; they were initially cultured in MH medium (Carron, et ál., 1989, modified MH medium (Montoro, et ál., 1993, 2000 and modified MS medium (Carron, et at,. 1992, no positive response being obtained by days 25 or 50. However, other trials were carried out with the integument in modified MS medium (1962, 0.67 mg/L BAP and 0.66 mg/L 2-4 D being added as medium for initiating embryogenesis, the formation of white, friable calluses being observed by day 25 in the two selected clones. These calluses were sub-cultured in MS supplemented with 0.35 mg/L BAP and 0.2 mg/L 2-4 D as callogenesis expression medium, embryogenic expression being observed in both clones by day 50. Equally friable white calluses were obtained from young leaves in the two clones in MS medium supplemented with 1.0 mg/L BAP, 1.0 mg/L ANA but without IBA and kinetin by day 25. Calluses sub-cultured in the same medium supplemented with 0.5 mg/L BAP and 0.5 mg/L ANA began to show increased friability after 50 days. culture. This work is a partial report of a macro-project for optimising a protocol for rubber (Hevea brasiliensis  multiplication by somatic embryogenesis.

Comparative studies on the mechanical properties of natural rubber and natural rubber filled with multi-walled carbon nanotubes

Science.gov (United States)

Ismail, R.; Ibrahim, A.; Rusop, M.; Adnan, A.

2018-05-01

The present article compares the mechanical properties of natural rubber (NR) and carbon nanotubes (CNTs) filled natural rubber composites. Four types of nanocomposite specimens are fabricated with different MWCNT loadings: 0 wt% (pure natural rubber), 1 wt%, 3 wt%, and 5 wt%. The specimens are tested for their mechanical properties. It is observed that the tensile strength, hardness and elongation break of CNTs filled rubber composites are remarkably higher than that of raw rubber indicating the inherent reinforcing potential of CNTs. Percentage of the elongation at break of rubber CNTs composites is lower than that of raw rubber.

Effects of forests, roads and mistletoe on bird diversity in monoculture rubber plantations.

Science.gov (United States)

Sreekar, Rachakonda; Huang, Guohualing; Yasuda, Mika; Quan, Rui-Chang; Goodale, Eben; Corlett, Richard T; Tomlinson, Kyle W

2016-02-23

Rising global demand for natural rubber is expanding monoculture rubber (Hevea brasilensis) at the expense of natural forests in the Old World tropics. Conversion of forests into rubber plantations has a devastating impact on biodiversity and we have yet to identify management strategies that can mitigate this. We determined the life-history traits that best predict bird species occurrence in rubber plantations in SW China and investigated the effects of surrounding forest cover and distance to roads on bird diversity. Mistletoes provide nectar and fruit resources in rubber so we examined mistletoe densities and the relationship with forest cover and rubber tree diameter. In rubber plantations, we recorded less than half of all bird species extant in the surrounding area. Birds with wider habitat breadths and low conservation value had a higher probability of occurrence. Species richness and diversity increased logarithmically with surrounding forest cover, but roads had little effect. Mistletoe density increased exponentially with rubber tree diameters, but was unrelated to forest cover. To maximize bird diversity in rubber-dominated landscapes it is therefore necessary to preserve as much forest as possible, construct roads through plantations and not forest, and retain some large rubber trees with mistletoes during crop rotations.

Chemical modifications of liquid natural rubber

Science.gov (United States)

Azhar, Nur Hanis Adila; Rasid, Hamizah Md; Yusoff, Siti Fairus M.

2016-11-01

Liquid natural rubber (LNR) was synthesized via photosentisized degradation of natural rubber (NR). LNR was modified into epoxidized liquid natural rubber (LENR) and hydroxylated liquid natural rubber (LNR-OH) using Na2WO4/CH3COOH/H2O2 catalytic system. Chemical structures of LNR and modified LNRs were characterized using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and 1H Nuclear Magnetic Resonance (NMR) spectroscopies. Integration of 1H NMR was used to calculate the epoxy content (%) of LENR. 1H NMR detected the formation of LNR-OH after prolonged heating and increased of catalyst in oxidation reaction.

Compósitos de borracha natural com polianilina Composites of natural rubber with polyaniline

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Patrini D. Galiani

2007-06-01

Full Text Available Compósitos de borracha natural (Hevea brasiliensis-BN/polianilina - PANI, com diferentes composições foram obtidos através da polimerização por emulsão do monômero anilina na presença da BN e do ácido dodecilbenzeno sulfônico (DBSA. Filmes finos e homogêneos foram obtidos por prensagem a quente. Os compósitos foram caracterizados por condutividade elétrica, FTIR, UV-vis-NIR, DSC e difração de raios X. Compósito com condutividade elétrica cerca de 14 ordens de grandeza maior que a BN foi obtido. Este alto valor de condutividade é atribuído à formação da PANI no estado dopado no compósito, que foi verificado através das técnicas de UV-vis-NIR e FTIR. Os resultados obtidos com a técnica de DSC e difratometria de raios X indicaram que os polímeros são imiscíveis e que a presença da borracha não altera significantemente a fase cristalina da PANI-DBSA no compósito.In this work composites with different compositions were obtained from natural rubber (Hevea brasiliensis (NR and polyaniline (PANI using the emulsion polymerization of aniline in the presence of NR and dodecylbenzenesulfonic acid (DBSA. The samples in film form were obtained by pressing the precipitate at 100 °C for 5 minutes. The composites were characterized by electrical conductivity, Fourier-transform infrared spectroscopy (FTIR, UV-vis-NIR spectroscopy, differential scanning calorimetry (DSC and X ray diffraction. Composites with electrical conductivity about 14 orders of magnitude higher than NR were obtained. The UV-vis-NIR and FTIR spectra showed that PANI-DBSA was formed in the composites, thus making it responsible for their high conductivity. The DSC thermograms indicated that the two polymers are immiscible and X ray diffraction evidenced that NB does not considerably affect PANI-DBSA crystalline phase in the composite.

The Cyclization of natural rubber

International Nuclear Information System (INIS)

Mirzataheri, M.

2000-01-01

The effect of solvent, temperature, time, weight percent of catalyst on the rate and mechanism of cyclization of natural rubber was studied in toluene and xylene solutions having tin tetra chloride catalyst (SnCl 4 ). Iodo metric titration show, with 8% SnCl 4 (based on polymer weight) cyclization occurs, leaving 27.4% of the total unsaturation. Infrared spectra of cyclized natural rubber show decreased absorption intensity at 840 and 780 cm -1 which are characteristic bands of the linear polymer and the appearance of absorption band at 890 cm -1 as cycles were formed. By using this chemical modification, natural rubber is transformed into a resinous thermoplastic, hard, non rubbery cyclized material with much less unsaturation than the original rubber, which could find commercial applications ad adhesives, printing inks, industrial and ship paints

Nutrient cycling in a RRIM 600 clone rubber plantation

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Murbach Marcos Roberto

2003-01-01

Full Text Available Few reports have been presented on nutrient cycling in rubber tree plantations (Hevea brasiliensis Muell. Arg.. This experiment was carried out to evaluate: the effect of K rates on the amount of nutrients transfered to the soil in a 13-year old Hevea brasilensis RRIM 600 clone plantation, nutrient retranslocation from the leaves before falling to the soil, and nutrient loss by dry rubber export. The experiment started in 1998 and potassium was applied at the rates of 0, 40, 80 and 160 kg ha-1 of K2O under the crowns of 40 rubber trees of each plot. Literfall collectors, five per plot, were randomly distributed within the plots under the trees. The accumulated literfall was collected monthly during one year. The coagulated rubber latex from each plot was weighed, and samples were analyzed for nutrient content. Increasing K fertilization rates also increased the K content in leaf literfall. Calcium and N were the most recycled leaf nutrients to the soil via litterfall. Potassium, followed by P were the nutrients with the highest retranslocation rates. Potassium was the most exported nutrient by the harvested rubber, and this amount was higher than that transfered to the soil by the leaf literfall.

Alternative sources of natural rubber

NARCIS (Netherlands)

Mooibroek, H.; Cornish, K.

2000-01-01

Rubber (cis-1,4-polyisoprene) is one of the most important polymers naturally produced by plants because it is a strategic raw material used in more than 40,000 products, including more than 400 medical devices. The sole commercial source, at present, is natural rubber harvested from the Brazilian

Seasonality of pathogenic fungi in mites of rubber tree plantations adjacent to fragments of Cerrado

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PR. Demite

Full Text Available Fungi are the most frequently observed pathogens of mite populations, helping to control them on different crops. Twenty-five samples of leaves were collected from rubber tree plantations adjacent to two fragments of Cerrado vegetation. Each rubber tree plantation had 25 plants selected for sampling and seven leaves from around each tree top were collected up to seven to eight meters above ground. Approximately 250 individuals of Calacarus heveae Feres, Phyllocoptruta seringueirae Feres, and Tenuipalpus heveae Baker, collected randomly, were mounted from each plantation. Hirsutella thompsoni Fisher was observed on all three mites and T. heveae was the most infected species. The highest infestation levels occurred from November to February (rainy season. In the dry season, infestation levels were below 5%. Hirsutella thompsonii has potential to be used as mycoacaricide during the rainy season.

Radiation induced graft copolymerization of acrylonitrile on natural rubber

International Nuclear Information System (INIS)

Claramma, N.M.; Mathew, N.M.; Thomas, E.V.

1989-01-01

Acrylonitrile graft natural rubber was prepared by initiating the polymerization of acrylonitrile in natural rubber field latex using γ-rays. The reaction was carried out at different rubber-monomer concentrations and the properties of the modified rubbers were compared with those of natural rubber and nitrile rubber. (author)

Microwave-Assisted Extraction and Physicochemical Evaluation of Oil from Hevea brasiliensis Seeds

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Evelyn C. Creencia

2018-04-01

Full Text Available The rubber tree (Hevea brasiliensis is exploited mainly for latex in view of its economic importance. However, one of its auxiliary products, the rubber seed, does not find any major applications, and hence, even the natural production of seeds itself remains underutilized. In this study, microwave-assisted Soxhlet extraction is used as a green alternative to extract the oil from seeds at a reaction time of 90 min and microwave power of 300 W. The objective of the study is to evaluate the effects of the processing conditions, including drying time, temperature, solid–solvent ratio, and extraction solvent, on the yield of rubber seed oil. Moreover, the microwave-assisted aqueous extraction (MAAE under acidic conditions is also investigated. Based on the results, n-hexane gave the best yield at an optimized 1:20 seed–hexane ratio at 72 °C compared with the conventional Soxhlet method and the acidic MAAE. Furthermore, the chemical characteristics of the oil showed a high value of free fatty acids (% FFA (1.15–7.61% and an iodine value (IV that ranges from 100–150. As a semi-drying oil, rubber seed oil (RSO can be used as an ingredient for surface coating and in the formulation of products where the presence of unsaturation is important.

Co-extraction of high-quality RNA and DNA from rubber tree (Hevea ...

African Journals Online (AJOL)

DR TONUKARI NYEROVWO

2012-05-15

May 15, 2012 ... method was also evaluated, and the results show that it was suitable for a variety of plants. Key words: Hevea ... Southeast Asia, where it covers more than 90% of the .... After air drying for. 10 min, it was ..... and cost-effective.

Crack Velocities in Natural Rubber.

Science.gov (United States)

1982-05-01

vulcanized natural rubber (3). The surprisingly low value for natural rubber was attributed to highly anisotropic elastic behavior at high strains...Dr. R.L. Rabie Hercules Incorporated WX-2, MS-952 Alleghany Ballistic Lab Los Alamos National Lab. P.O. Box 210 P.O. Box 1663 Washington, D.C. 21502

Evaluation of incubated defatted rubber seed meal with sheep rumen liquor for Pangasius diet

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Muhammad Agus Suprayudi

2015-10-01

Full Text Available ABSTRACT The research evaluated the use of rubber seed meal (Hevea brasiliensis; RBS incubated with sheep rumen liquor as a subtitution of soybean meal in catfish Pangasionodon sp. diet. The fish was cultured for 40 days and fed with the experimental diet containing RBS at five different diet compositions regarding to soybean meal substitution level, i.e. 0% (control, 12%, 23%, 34%, and 44%. Feeding was done three times a day to satiation. No significant different was found on fish-protein retention and survival rate in all treatments. Based on the study result, the use of rubber-seed meal (Hevea brasiliensis; RBS incubated with sheep rumen liquor could substitute soybean meal in catfish Pangasionodon sp. diet. Keywords: Hevea brasiliensis, Pangasionodon sp., catfish, sheep rumen liquor, rubber seed meal  ABSTRAK Penelitian ini mengevaluasi penggunaan tepung bungkil biji karet (Hevea brasiliensis; TBBK yang diinkubasi dengan cairan rumen domba sebagai pengganti tepung bungkil kedelai pada pakan ikan patin Pangasionodon sp. Pemeliharaan ikan dilakukan selama 40 hari dengan pemberian lima komposisi pakan berbeda sesuai tingkat substitusi tepung bungkil kedelai oleh tepung bungkil karet. TBBK yang ditambahkan untuk mengganti bungkil kedelai adalah sebesar 0%, 12%, 23%, 34% dan 44%. Pemberian pakan dilakukan selama tiga kali sehari secara at satiation. Tidak ditemukan perbedaan signifikan (P>0,05 pada nilai retensi protein dalam tubuh dan kelangsungan hidup ikan uji pada semua perlakuan. Berdasarkan hasil penelitian, dapat disimpulkan bahwa tepung bungkil biji karet yang diinkubasi dengan cairan rumen domba dapat digunakan sebagai pengganti bungkil kedelai pada pakan ikan patin Pangasionodon sp. Kata kunci: Hevea brasiliensis, Pangasionodon sp., patin, rumen domba, tepung biji karet 

Hevea brasiliensis natural rubber latex film vulcanization by gamma radiation containing n-butyl acrylate: properties and morphology; Filme de latex de borracha natural de Hevea brasiliensis vulcanizado por radiacao gama contendo acrilato de n-butila: propriedades e morfologia

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Ana Paula Pinho; Barros, Glaucione Gomes de [Brasilia Univ., DF (Brazil). Dept. de Quimica; Guedes, Selma M.L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

1997-07-01

Radiation vulcanization of natural rubber latex (RVNRL) in the presence of n-butyl acrylate (n-Ba) as sensitizer was carried out. The RVNRL films were investigated with respect to their thermal properties and morphology. The films presented two T{sub g} values obtained by DSC which were identified as due to linear and crosslinked domains. The thermal stability of the material was similar to that of linear material rubber. The morphology showed smooth regular surface characteristic of homogeneous phase domains. (author)

Responses of rubber leaf phenology to climatic variations in Southwest China

Science.gov (United States)

Zhai, De-Li; Yu, Haiying; Chen, Si-Chong; Ranjitkar, Sailesh; Xu, Jianchu

2017-11-01

The phenology of rubber trees (Hevea brasiliensis) could be influenced by meteorological factors and exhibits significant changes under different geoclimates. In the sub-optimal environment in Xishuangbanna, rubber trees undergo lengthy periods of defoliation and refoliation. The timing of refoliation from budburst to leaf aging could be affected by powdery mildew disease (Oidium heveae), which negatively impacts seed and latex production. Rubber trees are most susceptible to powdery mildew disease at the copper and leaf changing stages. Understanding and predicting leaf phenology of rubber trees are helpful to develop effective means of controlling the disease. This research investigated the effect of several meteorological factors on different leaf phenological stages in a sub-optimal environment for rubber cultivation in Jinghong, Yunnan in Southwest China. Partial least square regression was used to quantify the relationship between meteorological factors and recorded rubber phenologies from 2003 to 2011. Minimum temperature in December was found to be the critical factor for the leaf phenology development of rubber trees. Comparing the delayed effects of minimum temperature, the maximum temperature, diurnal temperature range, and sunshine hours were found to advancing leaf phenologies. A comparatively lower minimum temperature in December would facilitate the advancing of leaf phenologies of rubber trees. Higher levels of precipitation in February delayed the light green and the entire process of leaf aging. Delayed leaf phenology was found to be related to severe rubber powdery mildew disease. These results were used to build predictive models that could be applied to early warning systems of rubber powdery mildew disease.

The role of proteins on the thermal oxidative aging of radiation vulcanized natural rubber latex

International Nuclear Information System (INIS)

Abad, L.V.; Rosa, A. de la; Keizo Makuuchi; Fumio Yoshii

1996-01-01

The effect of Hevea latex proteins on the aging properties of radiation vulcanized natural rubber latex (RVNRL) was investigated. Unpurified RVNRL films exhibited better aging properties than the purified RVNRL films. A sharp decrease in tensile strength was observed after aging when RVNRL films were leached in 1% NH sub 4 OH. However, when these films were soaked in ethanol prior to leaching, the aging properties approximated those of the unleached samples. Kjeldahl and FT-IR analyses of the leached and unleached RVNRL films indicated a higher protein content for both the unleached and ethanol-soaked films than for leached films. Electrophoretic analysis of the proteins present in the NH, extracts of leached RVNRL films showed a high concentration of hevein. This protein was not found in the ATH, extracts of ethanol soaked films. Hevein was shown to improve the aging properties of RVNRL

Temporal stability of growth and yield among Hevea genotypes introduced to a non-traditional rubber growing region of peninsular India

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K.K. Vinod

2013-12-01

Full Text Available Extensive cultivation of Hevea brasiliensis in India now focus on non-traditional regions for rubber cultivation. As a prelude for selection of genotypes for commercial cultivation, many introduced genotypes are being tested in genotype adaptation experiments in these regions. Present study, reports for the first time, growth and yield adaptation of 28 genotypes in a non-traditional rubber growing region of peninsular India viz., the coastal Karnataka region. Agroclimate of this region was found favoring growth and establishment of all the genotypes evaluated. However, not all the genotypes grew and yielded well. Only four genotypes, RRII 203, KRS 25, PB 260 and PB 235 showed good growth and yield. On grouping, the genotypes fell into categories of moderate high yielders, moderate low yielders and low yielders. The most popular variety of the traditional region, RRII 105 did not perform well in this region. Biological stability in growth and yield of RRII 203 and PB 260 was identified as stable and these genotypes were the best adapted. KRS 25 and PB 235 had unstable yielding pattern. The best identified genotypes can be considered for extensive culture as single clone plantations or as major constituent of clone blends as well as parents in future breeding programmes. Other moderate stable yielders may be used for clone blending in smaller proportions and may be subjected to yield improvement.

Temporal stability of growth and yield among Hevea genotypes introduced to a non-traditional rubber growing region of peninsular India

Directory of Open Access Journals (Sweden)

K.K. Vinod

2010-09-01

Full Text Available Extensive cultivation of Hevea brasiliensis in India now focus onnon-traditional regions for rubber cultivation. As a prelude for selection of genotypes for commercial cultivation, many introduced genotypes are being tested in genotype adaptation experiments in these regions. Present study,reports for the first time, growth and yield adaptation of 28 genotypes in a non-traditional rubber growing region of peninsular India viz., the coastal Karnataka region. Agroclimate of this region was found favoring growth andestablishment of all the genotypes evaluated. However, not all the genotypes grew and yielded well. Only four genotypes, RRII 203, KRS 25, PB 260 and PB 235 showed good growth and yield. On grouping, the genotypes fell into categories of moderate high yielders, moderate low yielders and low yielders. The most popular variety of the traditional region, RRII 105 did not perform well in this region. Biological stability in growth and yield of RRII 203 and PB 260 was identified as stable and these genotypes were the best adapted. KRS 25 and PB 235 had unstable yielding pattern. The best identifiedgenotypes can be considered for extensive culture as single clone plantations or as major constituent of clone blends as well as parents in future breeding programmes. Other moderate stable yielders may be used for clone blending in smaller proportions and may be subjected to yield improvement.

Karakteristik Pembakaran Biobriket Kulit dan Cangkang Karet (Hevea Brasiliensis dengan Perekat Glyserin

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I Wayan Wawan Mariki

2017-05-01

Full Text Available Some studies have been done on utilizing biomass from agriculture such as the leather and shell of rubber (Hevea brasiliensis were not used optimally in Indonesia as an alternative energy which developed by making biobriquet to achieved the higher energy that could be used in the combustion process. In this study, the biobriquet was made of the leather and the shell of rubber by comparisson of the leather and shell were: 0%: 91%; 45.5%: 45.5%; 55%: 36%; 64%: 27%; 91%: 0%.Glyserin 9% for each percentage of biobriquet was used as adhesive material and the drying temperature of 110 C. This study aims to investigate the characteristics of biobriquet combustion which made of the leather and shell of rubber. The results shows that the biobriquet combustion process which made of 64% rubber leather and 27% rubber shell has a calorific value of 5313,923 Kal/gr. In 20 seconds of initial ignition, the combustion process shows the improvement such as increased concentrations of the flammable leather, bluish red fire.

Biobased products from rubber, jatropha and sunflower oil

NARCIS (Netherlands)

Bin Abu Ghazali, Yusuf

2015-01-01

In dit proefschrift wordt onderzoek beschreven naar het identificeren van interessante producten uit de zaden van de rubber boom (Hevea brasiliensis). Deze zaden worden momenteel niet gebruikt en in vele rubberplantages gezien als afval. De zaden bestaan uit een harde schil (39 wt%) en een kern (61

Effect of Recycled Rubber Particles and Silica on Tensile and Tear Properties of Natural Rubber Composites

Directory of Open Access Journals (Sweden)

Velu CHANDRAN

2016-05-01

Full Text Available Application of scrap rubber and worn out tires in natural rubber compounds has been studied. The scrap rubber can, however, be recycled and compounded with natural rubber and thus can be generated as a rubber composite. In this work, recycled rubber particles (RRP were prepared using pulverization process. Then, RRP was blended with natural rubber and silica compounds, and it was synthesized by two- roll mill and hydraulic press at specified operating conditions. The samples ranging from 0 to 40 phr of RRP loaded with silica were used as constant filler. The mechanical properties and morphological analysis were carried out. The results showed that tensile strength and elongation at break gradually decreased with increasing RRP loading in natural rubber and silica compounds. Tensile modulus went down at 10 phr of RRP and then showed an increasing trend. Hardness increased up to 30 phr of RRP and tear strength increased up to 20 phr of RRP. A comparative study was also carried out with virgin natural rubber vulcanizates. The incorporation of RRP and silica up to 20 phr in natural rubber did not lower the performance of rubber articles. Morphological studies revealed that better filler dispersion, interfacial adhesion, and cross link density could increase the tensile and tear strengths.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.7330

No significant transfer of N and P from Pueraria Phaseoloides to Hevea Brasiliensis via Hyphal links of Arbuscular Mycorrhiza

DEFF Research Database (Denmark)

Ikram, A.; Jensen, E.S.; Jakobsen, I.

1994-01-01

The possible role of arbuscular mycorrhizal fungi in the transfer of nitrogen and phosphorus from Pueraria phaseoloides (donor) to Hevea brasiliensis (receiver) was examined. P. phaseoloides is used as a cover crop in rubber tree (H. brasiliensis) plantations. Roots of donor and receiver plants...

KETERSEDIAAN TEPUNGSARI DALAM MENOPANG PERKEMBANGAN ANAKAN LEBAH MADU Apis mellifera DI AREAL RANDU (Ceiba pentandra DAN KARET (Hevea brasilliensis

Directory of Open Access Journals (Sweden)

Sri Minarti

2012-04-01

� ABSTRACT This research aims to learn about the potency of honeybee Apis mellifera based on the intensity of working in gathering pollen, skill to gather pollen into the nest and form a brood during the pasturing in the silk-cotton tree (Ceiba pentandra plant and rubber tree (Hevea brasilliensis plant area. The subjects that are used are 7 (seven colonies of honeybee Apis mellifera with the queen at the age of 3 months, that each of them supports by 9 active frames. The observation does during the silk-cotton flower and rubber flower season during 4 months totally. During the research, the whole of colonies do not get the supplement food in everything form, so that they rely on natural food from the main plant source even the other plant around the pasturing area. Parameter that is observed includes: the amount of the pollen porter worker, the capacious of pollen nest and the capacious of brood. Data that is taken from the result of the research is analysed by T test non-form a pair to distinguish the entire variable that is measured. To know the closeness level of the connection between the amount of the pollen porter worker bee toward the capacious of pollen nest and the capacious of brood, it is used a simple regression analysis (Sudjana, 1994. The result of the analysis shows that the top activity of the pollen  worker bee in the kapuk tree area occurred at 07.00 – 07.30 (97,64 ± 19,96 bees, while in the rubber tree area occurred at 09.00 – 09.30 (267,12 ± 113,76 bees, the capacious of pollen bunch in the rubber tree area (64,7152  ±  28,1153 cm² noticeable smaller than the kapuk  tree area (275,1080  ±  91,95 cm², while the capacious of brood each of them is  1527.78 ± 575,57 cm² and  1765.79± 384,84 cm2.   Keywords : Honey bee, tepungsari, brrod, kapuk tree (Ceiba pentandra and rubber tree (Hevea brasiliensis

SUPPLY-CHAIN OF NATURAL RUBBER IN INDONESIA

Directory of Open Access Journals (Sweden)

Bustanul Arifin

2011-08-01

Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 st1\\:*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} The study examines the supply chain of natural rubber production in Indonesia and assessing the transmission of prices to rubber growers and provides recommendations for a suitable scheme that would help to ensure high production standards and a sustainable return for natural rubber production.  The frameworks to examine the performance of supply chain of rubber marketing rely mostly on the efficiency level of marketing system of natural rubbers, including the value chain principles in marketing margin, and revealed price transmission from consumers to growers. The results show that the roles of subdistrict middlemen are extremely crucial in moving up the slabs from the village level to urban areas, where trader-brokers are expecting the slabs to be forwarded directly to crumb-rubber factories.  Changes in world price, hence the profits being accumulated by traders and rubber factories, are not transmitted properly to rubber farmers and/or sharetappers. Information asymmetry, the access over price information, and immediate response of rubber growers to the change in world price could explain this non-cointegration in price data between growers and exporters.  In the near future, the policy reforms in supply chain of natural rubber marketing in Indonesia should carefully address these issues in a more comprehensive manner.  Finally, in order to contribute to the positive environmental and social benefits, the major challenge for natural rubber

PIGMENTOS FOTOSSINTÉTICOS EM CLONES DE SERINGUEIRA SOB ATAQUE DE OÍDIO

Directory of Open Access Journals (Sweden)

Gisely Cristina Gonzalez

2013-01-01

Full Text Available The rubber tree [Hevea brasiliensis (Willd. ex Adr. Of Juss. Muell. Arg.] can be affected by the occurrence of the fungus Oidium heveae, which causes one of the most important diseases of rubber trees, powdery mildew. This work meet changes in photosynthetic pigments, an indicator of oxidative stress, in seedlings of three Hevea brasiliensis clones, RRIM 600, GT1 and PR255, under infection in Oidium heveae. The experiment was conducted in an open environment under natural photoperiod conditions and at the beginning of the trial, the rubber plants that would be inoculated were sprayed with an aqueous suspension containing Oidium heveae at a concentration of 16 x 104 conidia mL-1. On the day of inoculation and after 48, 96, 144 and 192 h leaf samples were collected for the determination of photosynthetic pigments. Degradation in photosynthetic pigments in the period of infection was observed in rubber tree clones studied; thus, there is oxidative stress in clones of rubber trees. No promising genetic material for genetic improvement work stress tolerance by Oidium heveae was identified.

Early growth of promising rubber tree clones of Hevea brasiliensis (Willd. ex A. Juss. Müll. Arg. in an agroforestry system in Caquetá, Colombia

Directory of Open Access Journals (Sweden)

Armando Sterling Cuéllar

2015-07-01

Full Text Available This study aimed to evaluate the early growth of three rubber tree clones (Hevea brasiliensis (FX 4098, FDR 5788, and control IAN 873 in four planting systems with cupuasu (Theobroma grandiflorum and banana trees (Musa AAB at two localities in Caquetá (Colombian Amazonia. A completely randomized block design with three replications and split-plot arrangement, analyzed with a general linear mixed model, was used at each locality. Total height (AT, trunk circumference (CT, canopy area (AC and leaf area index (IAF were evaluated one and two years after establishment of rubber trees. Trunk circumference was the variable most correlated with different growth indices (r ≥ 0.94. Four growth indices were strongly influenced by temporal and clonal variation and by planting system (p < 0.01. The only significant differences between the two localities were for AC (p < 0.05. System x clone interaction was significant for IAF (p < 0.01. After two years, the highest growth indices were observed in rubber tree clone FX 4098 (AT = 4.43 m; CT = 13.00 cm, AC = 4.62 m2; LAI = 1.37, and in two of the three agroforestry systems (AT ≥ 4.08 m, CT ≥ 11.43 cm, AC ≥ 4.01 m2; IAF ≥ 1.54 compared with the control system (monoculture.

Enzymic and structural studies on processed proteins from the vacuolar (lutoid-body) fraction of latex of Hevea brasiliensis

NARCIS (Netherlands)

Subroto, T; de Vries, H; Schuringa, JJ; Soedjanaatmadja, UMS; Hofsteenge, J; Jekel, PA; Beintema, JJ

2001-01-01

The lutoid-body (bottom) fraction of latex from the rubber tree (Hevea brasiliensis) contains a limited number of major proteins. These are the chitin-binding protein hevein, its precursor and C-terminal fragment of the precursor, a basic chitinase/lysozyme, and a beta-1,3-glucanase. The content and

Below-ground interspecific competition for water in a rubber agroforestry system may enhance water utilization in plants.

Science.gov (United States)

Wu, Junen; Liu, Wenjie; Chen, Chunfeng

2016-01-19

Rubber-based (Hevea brasiliensis) agroforestry systems are regarded as the best way to improve the sustainability of rubber monocultures, but few reports have examined water use in such systems. Accordingly, we tested whether interplanting facilitates water utilization of rubber trees using stable isotope (δD, δ(18)O, and δ(13)C) methods and by measuring soil water content (SWC), shoot potential, and leaf C and N concentrations in a Hevea-Flemingia agroforestry system in Xishuangbanna, southwestern China. We detected a big difference in the utilization of different soil layer water between both species in this agroforestry system, as evidenced by the opposite seasonal fluctuations in both δD and δ(18)O in stem water. However, similar predawn shoot potential of rubber trees at both sites demonstrating that the interplanted species did not affect the water requirements of rubber trees greatly. Rubber trees with higher δ(13)C and more stable physiological indexes in this agroforestry system showed higher water use efficiency (WUE) and tolerance ability, and the SWC results suggested this agroforestry is conductive to water conservation. Our results clearly indicated that intercropping legume plants with rubber trees can benefit rubber trees own higher N supply, increase their WUE and better utilize soil water of each soil layer.

Ultraviolet curing of acrylated liquid natural rubber for surface coating application

OpenAIRE

Kannikar Kwanming; Pairote Klinpituksa; Wae-asae Waehamad

2009-01-01

Ultraviolet curable acrylated liquid natural rubber was prepared by grafting of photosensitive molecule onto liquid natural rubber for surface coating application. The liquid natural rubber (LNR) was firstly obtained by degradation of natural rubber latex with hydrogen peroxide and cobalt acetylacetonate at 65oC for 72 hrs. The preparation of acrylated natural rubber was carried out by the reaction of acrylic acid and epoxidized liquid natural rubber (ELNR) prior obtained from LNR with formic...

Functionalization of Liquid Natural Rubber via Oxidative Degradation of Natural Rubber

Directory of Open Access Journals (Sweden)

Suhawati Ibrahim

2014-12-01

Full Text Available Natural rubber (NR is a high molecular weight natural polymer and can be degraded to liquid natural rubber (LNR leaving certain functional groups at the end of chains. In this study, LNR samples prepared via oxidative degradation using H2O2 and NaNO2 as reagents were found to have different end groups depending on the pH of the reaction medium. In an acidic medium, LNR with hydroxyl terminal groups was formed as the degradation reaction was initiated by hydroxyl radicals produced from decomposition of peroxynitrite acid. In contrast, a redox reaction took place in an alkaline medium to yield LNR with carbonyl terminal groups. The mechanisms of reaction are discussed and proposed to explain the formation of different end groups when reaction carried out in acidic and alkaline media. Chain degradation in an acidic medium seems to be more effective than in an alkaline medium, and thus yields LNR with lower Mn.

Fabrication of shape memory natural rubber using palmitic acid

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Jeff Sze-Hua Wee

2017-10-01

Full Text Available This paper investigates the practicability of fabricating a shape memory natural rubber with the use of palmitic acid as the swelling agent. Strips of natural rubber samples were swollen in molten palmitic acid at 75 °C. Equilibrium swelling of natural rubber with palmitic acid was found to occur at approximately 50 min of swelling time. Under cooling effect, the palmitic acid crystallized to form a percolated crystalline platelet network. These networks allow fabricated shape memory natural rubber (SMNR to deform and recover its shape at a temperature above the melting point of palmitic acid. Under controlled uniaxial stress, the natural rubber sample with 0 parts per hundred rubber (phr carbon black loading exhibits fixity and recovery of 80 ± 10%. Motivation of this research is primarily on practicability of palmitic acid to be used as a swelling agent for shape memory properties. Results show that palmitic acid is a relatively good swelling agent to induce shape memory properties into natural rubber.

Thermal properties of hydrogenated liquid natural rubber

Science.gov (United States)

Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

2015-09-01

Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion.

Thermal properties of hydrogenated liquid natural rubber

International Nuclear Information System (INIS)

Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

2015-01-01

Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion

Thermal properties of hydrogenated liquid natural rubber

Energy Technology Data Exchange (ETDEWEB)

Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

2015-09-25

Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion.

Performance Study of the Natural Rubber Composite with Clay Minerals

International Nuclear Information System (INIS)

Nyo Nyo Myint; Tin Tin Aye; Kyaw Myo Naing; Nyunt Wynn

2008-03-01

The preparation, characterization and some applications of natural rubber clay composite have been studied. This study investigated the possibility of natural rubber latex to replace some part of natural clays. In formulation of rubber clay composite from natural rubber latex and various clay minerals, three main steps were involved (i) preparation of latex cream (ii) prevulcanization of latex cream (iii) mixing vulcanized latex compound, with other ingredients. In each step, several parameters have been carefully investigated to optimize the performance of natural rubber clay composite production. The composite products were of better quality and can be considered to be more cost effective.

Carboxy terminated rubber based on natural rubber grafted with acid anhydrides and its adhesion properties

International Nuclear Information System (INIS)

Klinpituksa, P; Kongkalai, P; Kaesaman, A

2014-01-01

The chemical modification of natural rubber by grafting of various polar functional molecules is an essential method, improving the versatility of rubber in applications. This research investigated the preparation of natural rubber-graft-citraconic anhydride (NR-g-CCA), natural rubber-graft-itaconic anhydride (NR-g-ICA), and natural rubber-graft-maleic anhydride (NR-g-MA), with the anhydrides grafted to natural rubber in toluene using benzoyl peroxide as an initiator. Variations of monomer content, initiator content, temperature and reaction time of the grafting copolymerization were investigated. The maximum degrees of grafting were 1.06% for NR-g-CCA, 4.66% for NR-g-ICA, and 5.03% for NR-g-MA, reached using 10 phr citraconic anhydride, 10 phr of itaconic anhydride, or 8 phr of maleic anhydride, 3 phr benzoyl peroxide, at 85, 80 and 80°C for 2, 2 and 3 hrs, respectively. Solvent-based wood adhesives were formulated from these copolymers with various contents of wood resin in the range 10-40 phr. The maximal 289 N/in cleavage peel and 245.7 KPa shear strength for NR-g-MA (5.03% grafting) were obtained at 40 phr wood resin

Study on wood vinegars for use as coagulating and antifungal agents on the production of natural rubber sheets

Energy Technology Data Exchange (ETDEWEB)

Baimark, Yodthong; Niamsa, Noi [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahasarakham University, Mahasarakham 44150 (Thailand)

2009-06-15

Coagulating and antifungal properties of wood vinegars in the preparation process of Hevea brasiliensis natural rubber (NR) sheets were investigated and compared with those of formic and acetic acids. The wood vinegars produced from biomasses such as inner coconut shell, bamboo and Eucalyptus woods were evaluated. It was found that plasticity retention index, Mooney viscosity and mechanical properties of NR coagulated by wood vinegars were similar to those using acetic acid and better than using formic acid. The antifungal efficiency of coagulants determined from a fungi growth area on NR sheet surfaces was found in the following order: coconut shell wood vinegar > bamboo wood vinegar {approx} Eucalyptus wood vinegar > acetic acid {approx} formic acid. The antifungal efficiency of the wood vinegars was strongly depended upon their phenolic compound contents and confirmed through the inhibitory growth of the main fungi, Penicillium griseofulvum, on potato dextrose agar. (author)

Preparation of vinyl acetate grafted natural rubber by irradiation method

Energy Technology Data Exchange (ETDEWEB)

Porntrairat, A.; Pattamaprom, C. [Center of Excellence on Natural Rubber Technology, Department of Chemical Engineering, Faculty of Engineering, Thammasat University, Pathumthani 12120 (Thailand)

2016-03-09

Improvement in properties of natural rubber could be done by several methods. In this research, gamma radiation technique, which is simple, accurate, easy to control and clean, was applied to enhance the properties of natural rubber (NR) in latex state. The purpose of this research is to study the appropriate condition for preparing grafted natural rubber latex by using irradiation method. Vinyl acetate monomers (VAc) were grafted onto natural rubber latex (NR-g-PVAc) at 0-10 kGys by gamma radiation from Cobalt-60 source at room temperature. Physical properties of grafted natural rubber such as chloroform number, swelling ratio and gel content were measured. The VAc content of NR-g-PVAc was investigated by titration and visualized by FTIR spectroscopy. The FTIR spectra of NR-g-PVAc prepared at 0-10 kGys showed characteristic peaks of the vinyl acetate confirming that VAc could be grafted onto natural rubber molecular chains effectively under appropriate irradiation conditions. From the result, radiation grafting was found to be a useful technique for grafting of vinyl acetate onto natural rubber.

How do rubber (Hevea brasiliensis) plantations behave under seasonal water stress in northeastern Thailand and central Cambodia?

Energy Technology Data Exchange (ETDEWEB)

Kumagai, Tomo' omi [Nagoya Univ., Nagoya (Japan); Mudd, Ryan G. [Univ. of Hawaii, Honolulu, HI (United States); Giambelluca, Thomas W. [Univ. of Hawaii, Honolulu, HI (United States); Kobayashi, Nakako [Nagoya Univ., Nagoya (Japan); Miyazawa, Yoshiyuki [Kyushu Univ. Fukuoka (Japan); Lim, Tiva Khan [Cambodian Rubber Research Institute, Phnom Penh (Cambodia); Liu, Wen [Univ. of Hawaii, Honolulu, HI (United States); Huang, Maoyi [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fox, Jefferson M. [East-West Center, Honolulu, HI (United States); Ziegler, Alan D. [National Univ. of Singapore (Singapore); Yin, Song [Cambodian Rubber Research Institute, Phnom Penh (Cambodia); Mak, Sophea Veasna [Cambodian Rubber Research Institute, Phnom Penh (Cambodia); Kasemsap, Poonpipope [Kasetsart Univ., Bangkok (Thailand)

2015-11-01

Plantation rubber (Hevea brasiliensis Müll. Arg.) is a viable economic resource for Southeast Asian countries. Consequently, rubber plantations are rapidly expanding into both climatically optimal and sub-optimal environments throughout mainland Southeast Asia, potentially changing the partitioning of water, energy, and carbon at multiple scales, compared with the traditional land covers they are replacing. Delineating the characteristics of biosphere-atmosphere exchange in rubber plantations is therefore important to understanding the impacts of such land use change on environmental processes. We have conducted eddy flux measurements in two rubber plantation sites: (1) Som Sanuk (SS), located northern Thailand; and (2) Cambodian Rubber Research Institute (CRRI), central Cambodia. Both sites have a distinct dry season. Measurements were made over a 3-year period. We used combination of actual evapotranspiration (E_T) flux measurements and an inversed version of a simple 2-layer E_T model for estimating the mean canopy stomatal conductances (g_s), which is among the most effective measures for describing water and energy exchanges and tree water use characteristics. A main novelty in this analysis is that the rubber canopy conductance can be extracted from total surface conductance (including the canopy and the vegetation floor effects) and hence environmental and biological controls on rubber tree gs are explicitly compared at each site in different seasons and years. It is demonstrated how each studied rubber plantation copes with each strong seasonal drought via tree water use strategies. Potential tree water use deficit (precipitation (P) – potential evaporation (E_{T_POT})) for each season (i.e., December-February: DJF, March-May: MAM, June-August: JJA, and September-November: SON) revealed in which season and how the water use should be controlled. We found that in seasons when actual tree water use deficit (P �

A comparative study of natural rubber modified with ground tire rubber of truck

OpenAIRE

Binti Haridan, Ili Liyana

2016-01-01

The recycling of waste rubber has considerable significance in term of environmental protection and energy conservation. Considering that most of the relevant literature is concerned with tire recycling, the aim of this work was to develop and characterize the elastomeric samples of natural rubber (NR) composites filled with ground tire rubber of truck (GTR) devulcanized by microwave (DGTR). The tire rubber was ground under ambient conditions and subjected to microwave exposure for 3, 5 and ...

Forecasting Natural Rubber Price In Malaysia Using Arima

Science.gov (United States)

Zahari, Fatin Z.; Khalid, Kamil; Roslan, Rozaini; Sufahani, Suliadi; Mohamad, Mahathir; Saifullah Rusiman, Mohd; Ali, Maselan

2018-04-01

This paper contains introduction, materials and methods, results and discussions, conclusions and references. Based on the title mentioned, high volatility of the price of natural rubber nowadays will give the significant risk to the producers, traders, consumers, and others parties involved in the production of natural rubber. To help them in making decisions, forecasting is needed to predict the price of natural rubber. The main objective of the research is to forecast the upcoming price of natural rubber by using the reliable statistical method. The data are gathered from Malaysia Rubber Board which the data are from January 2000 until December 2015. In this research, average monthly price of Standard Malaysia Rubber 20 (SMR20) will be forecast by using Box-Jenkins approach. Time series plot is used to determine the pattern of the data. The data have trend pattern which indicates the data is non-stationary data and the data need to be transformed. By using the Box-Jenkins method, the best fit model for the time series data is ARIMA (1, 1, 0) which this model satisfy all the criteria needed. Hence, ARIMA (1, 1, 0) is the best fitted model and the model will be used to forecast the average monthly price of Standard Malaysia Rubber 20 (SMR20) for twelve months ahead.

Effect of Graphite on the Properties of Natural Rubber

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Auda jabber Braihi

2016-09-01

Full Text Available Natural rubber-graphite composites (0, 1, 2, 3, 4 pphr graphite were prepared on a laboratory two-roll mill. Swelling measurements were used to evaluate the impacts of graphite on the properties of natural rubber. Swelling results showed that the volume fraction of natural rubber in the swollen gel, the interaction parameter, and the cross-link density decreased by increasing graphite loadings, while the average molecular weight of natural rubber between cross-links increased. Vulcanization results showed that only scorch time parameter increased with increasing graphite loadings, while other parameters (Max. torque, Min. torque, cure rate and cure rate index decreased. Both thermal and AC conductivities increased.

Preparation of sulfonic acid-containing rubbers from natural rubber vulcanizates

Science.gov (United States)

Poonsawat, Worapong; Poompradub, Sirilux; Ngamcharussrivichai, Chawalit

2014-06-01

In this work, a series of sulfonic acid-containing rubbers were prepared by aqueous phase oxidation of natural rubber vulcanizates in the presence of hydrogen peroxide (H2O2) and formic acid (HCOOH). The starting vulcanizates were neatly prepared via an efficient vulcanization (EV) system by varying mass ratio of N-cyclohexyl-2-benzothiazole sulfonamide (CBS), as an accelerator, to sulfur. The oxidation conditions were controlled at the molar ratio of H2O2: HCOOH = 1:1, the concentration of H2O2 = 15 wt.%, the temperature = 50 °C, and the reaction time = 3 h. The rubber materials before and after the oxidation were characterized for their physicochemical properties by using Fourier transform infrared spectroscopy, bomb calorimetry, acid-base titration and swelling measurements. The results indicated the presence of sulfonic acid group in the oxidized rubbers, generated by the oxidative cleaves of sulfide crosslinks in the rubber vulcanizates. The oxidation decreased the sulfur content of the rubber in which the level of sulfur loss was determined by the CBS/sulfur ratio. Moreover, the acidity of the oxidized products was correlated with the amount of sulfur remaining.

Radiation-induced deterioration of natural rubber and isoprene rubber vulcanizates

International Nuclear Information System (INIS)

Kohjiya, Shinzo; Matsumura, Yasushige; Yamashita, Shinzo; Matsuyama, Tomochika; Yamaoka, Hitoshi.

1984-01-01

Natural rubber (NR) and isoprene rubber (IR) were cured by sulfur and accelerator to give rubber vulcanizates. Both vulcanizates were subject to solvent extraction to purify them, followed by the γ-ray irradiation in air at room temperature. The deterioration by γ-ray (0-20 Mrad) was investigated by the changes of tensile properties, hardness, swelling, and ATR-IR spectra. The tensile strength decreased much by a few Mrad irradiation, which is elucidated due to the difficulty of stretch-induced crystallization of polyisoprene after the irradiation. Modulus at 50 % elongation, network-chain density, and hardness did not show significant variation with the γ-ray dose. These irradiation results suggest both degradation and crosslinking occur comparably in the rubber vulcanizates and the regularity of polyisoprene chains may be somewhat randomized to prevent them from crystallizing on stretching. (author)

Degradation of blending vulcanized natural rubber and nitril rubber (NR/NBR) by dimethyl ether through variation of elastomer ratio

Science.gov (United States)

Saputra, A. H.; Juneva, S.; Sari, T. I.; Cifriadi, A.

2018-04-01

Dimethyl ether can cause degradation of the rubber material seal in some applications. In order to use of natural rubber in industry, research about a blending of natural rubber (NR) and nitrile rubber (NBR) to produce rubber to meet the standard seal material application were conducted. This study will observe the degradation mechanisms that occur in the blending natural rubber and nitrile rubber (NR/NBR) by dimethyl ether. Nitrile rubber types used in this study is medium quality nitrile rubber with 33% of acrylonitrile content (NBR33). The observed parameters are percent change in mass, mechanical properties and surface morphology. This study is limited to see the effect of variation vulcanized blending ratio (NR/NBR33) against to swelling. The increase of nitrile rubber (NBR33) ratio of blending rubber vulcanized can reduce the tensile strength and elongation. The best elastomer variation was obtained after comparing with the standard feasibility material of seal is rubber vulcanized blending (NR/NBR33) with ratio 40:60 NR: NBR.

The Effect of Rubber Mixing Process on The Curing Characteristics of Natural Rubber

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Abu Hasan

2013-04-01

Full Text Available This research is aimed at studying the relationship between rubber mixing processes and curing characteristics of natural rubber. The curing characteristic analysis was carried out through a natural rubber formula having been masticated and mixed, followed by curing. As many as four mastication methods were finely applied; each respected four sequences of rubber mixing process. In the first method, rubber was masticated for 5 minutes and then rubber chemicals and carbon black N 330 were  simultaneously added. In the second and the third methods, rubber was masticated for 1 minute and then carbon blacks and rubber chemicals were also simultaneously added but using different type of fillers. In the fourth method, rubber was masticated for 3 minutes and then rubber chemicals and carbon black were subsequently added. The additions of rubber chemicals and carbon blacks to the masticated rubber were distinguished by the sequence and time allocated for each mixing process. The carbon blacks were added in two stages by which 10 phr was added first and the remaining 40 phr was added later along with oil. In another method, ratios of the carbon blacks addition (as done in the first  and the second stages were 20:30, 30:20, and 40:10. The examination results showed that rubber mixing process gave an impact on the changes of curing characteristics. They were much affected by the method of carbon black addition. The mixing temperature also had an effect on both curing time and curing rate in which the higher the mixing temperature, the lower the curing time and curing rate. Vulcanization temperature also affected the curing time and curing rate in which the higher the vulcanization temperature, the lower the curing time and the higher the curing rate. Lastly, particle size of carbon black also gave an impact on the curing time and curing rate in which the smaller the particle size, the lower the curing time and the higher the curing rate.

Growth trends, genotype-environment interaction and genetic gains in six-year-old rubber tree clones (Hevea in São Paulo State, Brazil

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Gonçalves Paulo de Souza

1998-01-01

Full Text Available Budwood from seven different clones of rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss. Müell. Arg.] was planted in replicated trials in four different test sites in the plateau region of the state of São Paulo, Brazil. The clones represented a range of imported germplasm, whereas the locations were selected to represent a range of rubber growing areas. Girths were measured for six years consecutively, before the initiation of tapping for latex. Total number of latex vessel rings (lvr and bark thickness (bt were measured at six years. The largest average for all characters was observed in Matão. Overall means for girth, total number of latex vessel rings and bark thickness at six years were 35.26 cm, 11.30 units and 4.83 mm, respectively. Both the test sites and clones showed statistically significant differences in girth, lvr and bt values. There were significant clone x site interactions. Girth at one year was not a reliable predictor of future field performance. Broad sense heritability for girth was 0.16, and for lvr and bt it was 0.28 and 0.40, respectively, at six years. Repeatability was quite high, from 0.52 to 0.75 for all characters in all years. When two clones out of seven were selected, expected genetic gain in girth was about 2.0%; for lvr and bt it was 7.0% and 14.6%, respectively.

Natural Rubber Modification For Upper Layer Of Rubberized Asphalt Paving Block AS Shock Absorber

OpenAIRE

Nasruddin, Nasruddin

2017-01-01

The research of rubber compounding modification for upper layer of rubberized asphalt paving block as shock absorber using natural rubber, styrene butadiene rubber (SBR) as synthetic rubber, fly ash as filler and also vegetable oil as plasticizer has been conducted. The research design was varying the filler Si-69, fly ash and palm oil. The five formulas A, B, C, D, and E designed by varying the amount of Si-69 (48.5; 50.75; 53.00; 55.25; and 57.50) phr; coal fly ash (4.75, 7.00, 9.25, 11.50 ...

Physico-mecha-nical properties of rubber seed shell carbon – filled natural rubber compounds

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L.O. Ekebafe

2010-07-01

Full Text Available Samples of rubber seed shells were carbonized at varying temperatures (100, 200, 300, 400, 500, 600, 700 and 800 °C for three hours each and sieved through a 150 μm screen. The portion of the rubber seed shell carbon that passed through the screen was characterized in terms of loss on ignition, surface area, moisture content, pH, bulk density, and metal content and used in compounding natural rubber. The characterization shows that the pH, conductivity, loss on ignition and the surface area increases with the increases of the heating temperature, unlike the bulk density which decreases. The compound mixes were cured using the efficient vulcanization system. Cure characteristics of compounds and physico-mechanical properties of the vulcanisates were measured as a function of filler loading along with that of N330 carbon-black filled natural rubbers. The results showed that the cure times, scorch times and the torque gradually increased, with increasing the filler content for rubber seed shell carbon-filled natural rubber, with the filler obtained at carbonizing temperature of 600 °C tending to show optimum cure indices. The physicomechanical properties of the vulcanisates increase with filler loading. The reinforcing potential of the carbonized rubber seed shell carbon was found to increase markedly for the filler obtained at the temperature range of 500-600 °C and then decreases with further increase in temperature.

Competitiveness and Exports Sustainability of the Indonesian Natural Rubber

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Rumbiati Kamaludin

2018-03-01

Full Text Available This paper examines Indonesian competitiveness in export of natural rubber commodities by employing set of revealed comparative advantage (RCA and Export competitive index (ECI with respect to global trade. The market structure that is formed on natural rubber commodities is calculated using Herfindahl Index and Concentration Ratio analysis tools shows the oligopoly-shaped market structure. Calculation of comparative advantage with RCA analysis shows that the four countries exporting natural rubber, namely Thailand, Indonesia, Malaysia and Vietnam each have a comparative advantage. Where Indonesia has a better comparative advantage than Thailand in the period 2011 to 2015. This result is different from the calculations made on competitive advantage (ECI in which Indonesia's natural rubber commodities are not more competitive than Thailand

Synthesis and characterization of silver nanoparticles in natural rubber

International Nuclear Information System (INIS)

Abu Bakar, N.H.H.; Ismail, J.; Abu Bakar, M.

2007-01-01

Silver nanoparticles are formed in natural rubber matrix via photo reduction of film cast from natural rubber latex (NRL) containing silver salt. The resulting NR-Ag nanocomposite is characterized using TEM, XRD and UV spectroscopic techniques. The nanoparticles, diameter ranging between 4 and 10 nm, are dispersed within distinct interfaces which correspond to the inter-particle boundaries of the NRL particles that form the matrix. The average width of the interfaces is 8 nm. X-ray diffraction (XRD) analysis confirms the nanoparticles as metallic silver of the face-centered cubic type. UV-vis absorption spectra show peaks characteristic of the surface plasmon resonance of nano-sized silver. A comparison with the results of formation of silver, obtained under similar reduction condition, in a series of matrices namely de-proteinized natural rubber latex (DNRL), NRL containing sodium dodecyl sulfate (SDS), aqueous solutions of bovain serum albumin and SDS, suggests that the protein in natural rubber is responsible for the formation of stable silver nanoparticles in the natural rubber (NR) matrix

Gas exchange in young Hevea brasiliensis (Willd. Ex A. Juss. Müll. Arg. (Euphorbiaceae plants in Antioquia (Colombia

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Oscar de Jesús Cordoba Gaona

2018-01-01

Full Text Available The aim of this study was to determine the behavior of Hevea brasiliensis from a study of photosynthetic performance in the environmental conditions of the rubber regions in northeast and lower Cauca of the department of Antioquia (Colombia as a baseline for future studies of clonal performance between different environments. Photosynthetic parameters were recorded by an infrared gas analysis, and for each of the photosynthetic parameters was estimated the area under the curve (AUC from 7 Hevea genotypes (clones. The maximum value of photosynthetic rates was reached at 8 hours in San Roque (10.97 µmol [CO2] m-2s-1 and 9 hours in Caucasia (7.84 µmol [CO2] m-2s-1. The maximum transpiration rates was 3.55 mmol [H2O] m-2s-1, in San Roque, and 5.16 mmol [H2O] m-2s-1 in Caucasia, while the maximum stomatal conductance was 0.18 mol [H2O] m-2s-1 y 0.16 mol [H2O] m-2s-1 in San Roque, and Caucasia respectively. The Caucasia-based rubber plants had higher cumulative net assimilation rates 271,934 µmol [CO2] m-2day-1, being higher than San Roque 226,287 µmol [CO2] m-2day-1. The mean carbon accumulation was obtained in San Roque (697,638 µmol [CO2] µmol photon-1day1. Hevea brasiliensis showed greater environmental adaptation with respect to gas exchange and the use of light energy in San Roque.

Performance of new Hevea clones from IAC 400 series Perfomance de novos clones de Hevea da série IAC 400

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Paulo de Souza Gonçalves

2007-06-01

Full Text Available The Hevea breeding program of Instituto Agronômico de Campinas (IAC has completed clonal evaluation on the following series: IAC 100, IAC 200 and IAC 300. The performance of 22 clones of Hevea brasiliensis (Willd. ex Adr. de Juss. Muell.-Arg., evolved at IAC, over a period of eleven years was evaluated in the Western Central part of the São Paulo State, Brazil. Among these 22 new clones, six were intraspecific hybrid clones (IAC 400, IAC 404, IAC 405, IAC 406, IAC 410, IAC 412 and the remaining are primary those resulted from selected ortets within half-sib progenies. An old popular clone RRIM 600, of Malaysian origin, was used as the control. The trial was laid out in a randomized block design with three replications. Yield performance over a period of four years, mean girth at the 11th year, girth increment before tapping and on tapping, thermal property of natural rubber produced, bark thickness, number of latex vessel rows in seven year virgin bark, percentage incidence of tapping panel dryness, wind damage and diseases like leaf and panel anthracnose have been observed. Sixty one percent of the clones were superior in relation to the control for yield. The clone IAC 400 recorded the highest yield (97.40 g tree-1 tap-1 over four years of tapping, followed by IAC 411 (78.87 tree-1 tap-1, whereas the control clone RRIM 600 recorded 50.86 g tree-1 tap-1. All selected clones were vigorous in growth. Girth increment of these clones was average to above average. Except for IAC 423, other clones had thick virgin bark at opening ranging from 4.84 mm for IAC 401 to 6.38 mm for IAC 416. The natural rubbers from IAC clones have shown good thermal stability up to 300ºC and no differences in the thermal behavior among rubber from clones of the IAC series and the clone RRIM 600 were found in inert atmosphere.O programa de melhoramento de Hevea do Instituto Agronômico de Campinas (IAC completou a avaliação dos clones da série IAC 100, IAC 200 e IAC

Ultraviolet curing of acrylated liquid natural rubber for surface coating application

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Kannikar Kwanming

2009-01-01

Full Text Available Ultraviolet curable acrylated liquid natural rubber was prepared by grafting of photosensitive molecule onto liquid natural rubber for surface coating application. The liquid natural rubber (LNR was firstly obtained by degradation of natural rubber latex with hydrogen peroxide and cobalt acetylacetonate at 65oC for 72 hrs. The preparation of acrylated natural rubber was carried out by the reaction of acrylic acid and epoxidized liquid natural rubber (ELNR prior obtained from LNR with formic acid and hydrogen peroxide in the ratio of 2:1 by weight in toluene at 80oC for 6, 9, 12, 18, and 24 hrs. It was found that the percentage of acrylate grafted onto liquid natural rubber depended on the reaction time. Surface coating was performed by using acrylated liquid natural rubber and 1,6-hexanediol diacrylate (HDDA or tripropylene glycol diacrylate (TPGDA as a crosslinker and Irgarcure 184 or Irgarcure 651 as a photoinitiator under UV exposure for 30, 60, and 90 seconds. The hardness test of cured products was investigated using the Pencil hardness test at pencil level of 2B to 6H. It was found that the highest hardness of surface coating was at pencil level of 4H for the product using TPGDA and Irgacure 651 in the ratio of 80:10 parts per hundred of rubber (phr. The cured products were able to resist to 2% H2SO4 and distilled water for more than 24 hrs.

Comparative Proteomics of Rubber Latex Revealed Multiple Protein Species of REF/SRPP Family Respond Diversely to Ethylene Stimulation among Different Rubber Tree Clones

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Zheng Tong

2017-05-01

Full Text Available Rubber elongation factor (REF and small rubber particle protein (SRPP are two key factors for natural rubber biosynthesis. To further understand the roles of these proteins in rubber formation, six different genes for latex abundant REF or SRPP proteins, including REF138,175,258 and SRPP117,204,243, were characterized from Hevea brasiliensis Reyan (RY 7-33-97. Sequence analysis showed that REFs have a variable and long N-terminal, whereas SRPPs have a variable and long C-terminal beyond the REF domain, and REF258 has a β subunit of ATPase in its N-terminal. Through two-dimensional electrophoresis (2-DE, each REF/SRPP protein was separated into multiple protein spots on 2-DE gels, indicating they have multiple protein species. The abundance of REF/SRPP proteins was compared between ethylene and control treatments or among rubber tree clones with different levels of latex productivity by analyzing 2-DE gels. The total abundance of each REF/SRPP protein decreased or changed a little upon ethylene stimulation, whereas the abundance of multiple protein species of the same REF/SRPP changed diversely. Among the three rubber tree clones, the abundance of the protein species also differed significantly. Especially, two protein species of REF175 or REF258 were ethylene-responsive only in the high latex productivity clone RY 8-79 instead of in RY 7-33-97 and PR 107. Some individual protein species were positively related to ethylene stimulation and latex productivity. These results suggested that the specific protein species could be more important than others for rubber production and post-translational modifications might play important roles in rubber biosynthesis.

Radiation vulcanization of natural rubber latex sensitized with commercial gases

International Nuclear Information System (INIS)

Chirinos, H.; Lugao, A.

2002-01-01

The industrial activities using natural rubber latex are fully compatible with rural areas in Amazon and other places in Brazil, as well as in other tropical countries. However the classical sulfur vulcanization presents many occupational problems for the workers in rural areas. Radiation vulcanization of natural rubber latex is a much more friendly process as sulfur compounds are not needed for crosslinking, although chemicals as acrylate monomers, particularly multifunctional acrylates are still used as sensitizers for radiation processes. Two commercial gases, acetylene and butadiene, were selected as sensitizers for the radiation vulcanization of natural rubber latex instead of acrylates. These gases accelerate the crosslinking rates of the cure process and lower the radiation dose required to achieve vulcanization of natural rubber latex and improve the mechanical properties to reduce the tackiness of rubber goods. (author)

Radiation vulcanization of natural rubber latex sensitized with commercial gases

Energy Technology Data Exchange (ETDEWEB)

Chirinos, H.; Lugao, A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

2002-07-01

The industrial activities using natural rubber latex are fully compatible with rural areas in Amazon and other places in Brazil, as well as in other tropical countries. However the classical sulfur vulcanization presents many occupational problems for the workers in rural areas. Radiation vulcanization of natural rubber latex is a much more friendly process as sulfur compounds are not needed for crosslinking, although chemicals as acrylate monomers, particularly multifunctional acrylates are still used as sensitizers for radiation processes. Two commercial gases, acetylene and butadiene, were selected as sensitizers for the radiation vulcanization of natural rubber latex instead of acrylates. These gases accelerate the crosslinking rates of the cure process and lower the radiation dose required to achieve vulcanization of natural rubber latex and improve the mechanical properties to reduce the tackiness of rubber goods. (author)

Caracterização mecânica e térmica da borracha natural formulada e vulcanizada dos clones: GT 1, IAN 873, PB 235 e RRIM 600 Mechanical and thermal characterization of compounds of natural rubber of the clones: GT 1, IAN 873, PB 235 and RRIM 600

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Ana C. Dall'Antonia

2009-01-01

Full Text Available Neste trabalho estudou-se o desempenho mecânico e térmico de compostos de borracha natural (Hevea brasiliensis de 4 diferentes clones (GT 1, IAN 873, PB 235 e RRIM 600 cultivados no Estado de São Paulo, assim como de uma mistura destes clones e de uma borracha comercial, GEB-1. Estas borrachas foram formuladas e vulcanizadas com tempos de 5, 7 e 9 minutos. A caracterização foi realizada por calorimetria exploratória diferencial, termogravimetria, ensaios de resistência à tração, análise dinâmico-mecânica, medidas de dureza Shore A, microscopia eletrônica de varredura e espectroscopia na região do infravermelho. Os resultados permitiram concluir que o tempo de vulcanização e o tipo de clone não influenciaram na temperatura de transição vítrea (Tg dos compostos. Os valores de Tg obtidos por DMA foram de cerca de -62 °C, e os resultados ensaios de dureza apresentaram valores próximos de 60 para todos os compostos estudados. Os ensaios de resistência à tração mostraram que o melhor desempenho mecânico foi obtido pelo clone RRIM 600. De acordo com os resultados obtidos neste trabalho, todos os clones atingiram as propriedades reportadas na literatura, podendo ser utilizados, em princípio, nas indústrias de artefatos de borracha separadamente ou na forma de mistura.The objective of this work was to study the mechanical and thermal performance of natural rubber (Hevea brasiliensis compounds of different types of clones (GT 1, IAN 873, PB 235 and RRIM 600, as well as a mixture made from these clones and a commercial rubber GEB-1. These rubbers were formulated and prepared in a two-roll mill and vulcanized at different times (5, 7 and 9 minutes. The evaluation of the mechanical and thermal performance of different natural rubber compounds was carried out by differential scanning calorimetry (DSC, thermogravimetry analysis (TGA, mechanical properties (tensile and hardness tests, dynamic mechanic thermal analysis (DMTA

Sugarcane bagasse ash: new filler to natural rubber composite

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Renivaldo José dos Santos

2014-12-01

Full Text Available Waste recycling has been the subject of numerous scientific researches regarding the environmental care. This paper reports the redirecting of sugarcane bagasse ash (SBA as new filler to natural rubber (NR/SBA. The NR/SBA composites were prepared using an opened cylinder mixer to incorporate the vulcanization agents and different proportions of residue (SBA. The ash contains about 70-90% of inorganic compounds, with silica (SiO2 being the main compound. The SBA incorporation improved the mechanical properties of the vulcanized rubber. Based on these results, a new use is proposed for the agro-industry organic waste to be implemented in the rubber vulcanization process, aimed at improving the rubber physical properties as well as decreasing the prices of natural rubber composites.

Preparation of Natural Rubber (NR) Based Nano-Sized Materials Using Sol-Gel Technique

International Nuclear Information System (INIS)

Dahlan Mohd; Mahathir Mohamed

2011-01-01

The objectives of this project are to prepare nano-sized natural rubber-based hybrid coating material by sol-gel technique; to explore the possibility of producing ENR-Si (epoxidized natural rubber-silica) cramer with toughening effects; and to use it in radiation curing of surface coating. Since early 1960s Malaysia has introduced various forms of value-added natural rubber such as Standard Malaysian Rubber (SMR), methylmethacrylate-grafted natural rubber (MG rubber), followed by liquid natural rubber and epoxidized natural rubber (ENR). Products such as liquid epoxidized natural rubber acrylate (LENRA) and thermoplastic natural rubber (TPNR) are still on-going research projects in Nuclear Malaysia. The former has strong possibility to be used as radiation-sensitive comparabilities in TPNR blends, besides its original purpose for example in radiation curing of surface coating. But earlier findings indicated that, to make it (as for surface coating) more effective, reinforcement system is needed to be introduced. Strong candidate is silica by sol-gel technique, since common reinforcement filler for example carbon black has drawbacks in this particular case. This technique was introduced in late 1960s to produce metal oxides such as silica and titanium oxides in solution. (author)

Liberação de componentes do extrato de Casearia sylvestris Swartz empregando membranas de látex natural como suporte

OpenAIRE

Trecco, Alberto [UNESP; Borges, Felipe Azevedo [UNESP; Perri, Elaíse G. [UNESP; Santos, André Gonzaga dos [UNESP; Chin, Chung Man [UNESP; Herculano, Rondinelli Donizetti [UNESP

2014-01-01

Natural Rubber Latex (NRL) membrane, made from latex extracted from the rubber tree Hevea brasiliensis, has shown great potential for use in the biomedicine and biomaterials area. Thanks to its biocompatibility and low rejection rate, it has been used for implants and grafts, acting as a stimulant of angiogenesis and cell adhesion and as a barrier against infectious agents. Besides these applications, the membranes are used as model release systems, to assess the release behavior of drugs and...

SNP identification from RNA sequencing and linkage map construction of rubber tree for anchoring the draft genome.

Science.gov (United States)

Shearman, Jeremy R; Sangsrakru, Duangjai; Jomchai, Nukoon; Ruang-Areerate, Panthita; Sonthirod, Chutima; Naktang, Chaiwat; Theerawattanasuk, Kanikar; Tragoonrung, Somvong; Tangphatsornruang, Sithichoke

2015-01-01

Hevea brasiliensis, or rubber tree, is an important crop species that accounts for the majority of natural latex production. The rubber tree nuclear genome consists of 18 chromosomes and is roughly 2.15 Gb. The current rubber tree reference genome assembly consists of 1,150,326 scaffolds ranging from 200 to 531,465 bp and totalling 1.1 Gb. Only 143 scaffolds, totalling 7.6 Mb, have been placed into linkage groups. We have performed RNA-seq on 6 varieties of rubber tree to identify SNPs and InDels and used this information to perform target sequence enrichment and high throughput sequencing to genotype a set of SNPs in 149 rubber tree offspring from a cross between RRIM 600 and RRII 105 rubber tree varieties. We used this information to generate a linkage map allowing for the anchoring of 24,424 contigs from 3,009 scaffolds, totalling 115 Mb or 10.4% of the published sequence, into 18 linkage groups. Each linkage group contains between 319 and 1367 SNPs, or 60 to 194 non-redundant marker positions, and ranges from 156 to 336 cM in length. This linkage map includes 20,143 of the 69,300 predicted genes from rubber tree and will be useful for mapping studies and improving the reference genome assembly.

Shear modulus and damping ratio of natural rubber containing carbon nanotubes

Science.gov (United States)

Ismail, R.; Ibrahim, A.; Rusop, M.; Adnan, A.

2018-05-01

This paper presents the results of an investigation into the potential application of Natural rubber (NR) containing Carbon Nanotubes (CNTs) by measuring its shear modulus and damping ratio. Four different types of rubber specimens which fabricated with different MWCNT loadings: 0 wt% (pure natural rubber), 1 wt%, 3 wt%, and 5 wt%. It is observed that the shear modulus and damping ratio of CNTs filled rubber composites are remarkably higher than that of raw rubber indicating the inherent reinforcing potential of CNTs.

Long rotation swidden systems maintain higher carbon stocks than rubber plantations

DEFF Research Database (Denmark)

Bruun, Thilde Bech; Berry, Nicholas; De Neergaard, Andreas

2018-01-01

in fallows were 1.5 ± 0.12 Mg C ha−1 yr−1 and 1.9 ± 0.14 Mg C ha−1 yr−1 in rubber plantations. When comparing time-averaged carbon stocks of swidden systems to rubber plantations with 30 year rotation periods, the stocks of swidden systems with rotation times of 5 and 10 years were 19% and 13% lower......Conversion of shifting cultivation to rubber (Hevea brasiliensis) plantations is one of the dominant land use changes in montane mainland areas of Southeast Asia, with the area of rubber expected to quadruple by 2050. However, the impacts of this transition on total ecosystem carbon stocks...... are poorly quantified. We undertook a chronosequence study to quantify changes in ecosystem carbon stocks following conversion from swidden agriculture to rubber plantations in Northern Laos. We measured above-ground biomass stocks and collected volume specific soil samples across rubber plantations...

Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

Science.gov (United States)

Xu, Tiwen; Jia, Zhixin; Luo, Yuanfang; Jia, Demin; Peng, Zheng

2015-02-01

The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress-strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

The role of linked phospholipids in the rubber-filler interaction in carbon nanotube (CNT) filler natural rubber (NR) composites

NARCIS (Netherlands)

Le, H.H.; Abhijeet, S.; Ilish, S.; Klehm, J.; Henning, S.; Beiner, M.; Sarkawi, S.S.; Dierkes, Wilma K.; Das, A.; Fischer, D.; Stöckelhuber, K.-W.; Wiessner, S.; Khatiwada, S.P.; Adhikari, R.; Pham, T.; Heinrich, G.; Radusch, H.-J.

2014-01-01

The aim of the present work is to evidence the role of the linked phospholipids of natural rubber (NR) in the rubber-carbon nanotube (CNT) interactions in rubber composites. Three rubbers namely NR, deproteinized NR (DPNR) and a synthetic rubber isoprene (IR) were used as matrix for CNTs. The

A review of the Mycrocylus ulei Ascomycetes fungus, causative agent of South American rubber-leaf blight Revisión sobre el hongo Microcyclus ulei, agente causal del mal suramericano de la hoja del caucho

Directory of Open Access Journals (Sweden)

Ancízar Aristizábar Fabio

2006-12-01

Full Text Available The Microcyclus ulei Ascomycetes fungus is the causal agent of south-American leaf blight (SALB, this being one of the most important diseases affecting the natural rubber tree (Hevea brasiliensis in Latina-America and has been responsible for numerous economic losses. This fungus has presented high physiological variability, suggesting its great adaptability. HCN tolerance has been described as being one of the mechanisms associated with its virulence. Resistant Hevea clones have been obtained by genetic improvement; however, the mechanisms associated with this are still not well known. Greater knowledge of this pathogen will lead to developing new control strategies and better understanding of the mechanisms associated with host resistance. Key words: Microcyclus ulei, SALB, Hevea brasiliensis.El hongo ascomycete Microcyclus ulei es el agente causal del SALB que es una de las enfermedades más importan­tes del árbol de caucho natural (Hevea brasiliensis en América Latina y ha sido responsable de numerosas pérdidas económicas. Este hongo ha presentado alta variabilidad fisiológica y se sugiere su alta adaptabilidad, dentro de los mecanismos asociados a su virulencia se ha descrito la tolerancia al HCN. Se han obtenido clones de Hevea resistentes mediante mejoramiento genético, sin embargo, aun no son bien conocidos los mecanismos asociados a ésta. Un mayor conocimiento de este patógeno permitirá el desarrollo de nuevas estrategias de control así como el mayor entendimiento de los mecanismos asociados a resistencia del hospedero. Palabras clave: Microcyclus ulei, SALB, Hevea brasiliensis.

Polymer Electrolyte Prepared from Highly Deproteinized Natural Rubber Having Epoxy Group

Science.gov (United States)

Klinklai, W.; Kawahara, S.; Isono, Y.; Mizumo, T.; Yoshizawa, M.; Ohno, H.

Deproteinized natural rubber having epoxy group (EDPNR) was applied to transport Li+ as a solid polymer electrolyte. The deproteinized natural rubber, incubated with proteolytic enzyme and surfactant, was subjected to epoxidation followed by oxidative depolymerization in latex stage. The resulting rubber was proved to be a liquid deproteinized natural rubber (LEDPNR) having polar epoxy groups, low Tg, low Mn and well-defined terminal units. Ionic conductivity of LEDPNR mixed with alkali metal salts was investigated through impedance analysis to clarify an effect of proteins present in the rubber. The ionic conductivity of the resulting LEDPNR depended on the kind of salts, their concentrations and temperature. The ionic conductivity of LEDPNR/lithium bis(trifluoromethan sulfonyl)imide (LiTFSI) was higher than that of LEDPNR/ lithium perchlorate (LiClO4). The difference in the ionic conductivity was attributed to the solubility of the salts as results of both high-resolution solid-state 13C-NMR spectroscopy and measurements of spin-lattice relaxation time. The conductivity of LEDPNR/LiTFSI was also dependent upon concentrations of LiTFSI and it reached the highest value at 20 wt%, which was different from the monotonic increase in the Li+ conductivity of liquid epoxidized natural rubber prepared from untreated natural rubber.

The water-food nexus of natural rubber production

Science.gov (United States)

Chiarelli, D. D.; Rosa, L.; Rulli, M. C.; D'Odorico, P.

2017-12-01

The increasing global demand for natural rubber (100% increase in the last 15 years) is for most part met by Malaysia and Indonesia, and - to a lesser extent - other countries in south-east Asia and Africa. The consequent expansion of rubber plantation has often occurred at the expenses of agricultural land for staple food, particularly in southeast Asia, where most of the land suitable for agriculture is already harvested for food crops or other uses. Here we investigate the extent to which the ongoing increase in rubber production is competing with the food system and affecting the livelihoods of rural communities in the areas of production and their appropriation of natural resources, such as water. We also investigate to what extent the expansion of rubber plantations is taking place through large scale land acquisitions (LSLAs) and evaluate the impacts on rural communities. Our results show how rubber production has strong environmental, social and economic impacts. Despite their ability to bring employment and increase the average income of economically disadvantaged areas, rubber plantations may threaten the local water and food security and induce a loss of rural livelihoods, particularly when the new plantations result from LSLAs that displace semi-subsistence forms of production thereby forcing the local populations to depend on global markets.

Development of radiation-curable resin based on natural rubber

Energy Technology Data Exchange (ETDEWEB)

Mohd, Dahlan; Harun, Abdul Ghani [Nuclear Energy Unit, Bangi, Selangor (Malaysia)

1994-12-31

A new radiation curable resin based on natural rubber has been developed. The resin was based on the reaction between low molecular weight epoxidised natural rubber and acrylic acid. When formulated with reactive monomers and photoinitiator, it solidified upon irradiation with UV light. The resin may find applications in coating for cellulosic-based substrates and pressure-sensitive adhesive.

Development of radiation-curable resin based on natural rubber

International Nuclear Information System (INIS)

Dahlan Mohd; Abdul Ghani Harun

1993-01-01

A new radiation curable resin based on natural rubber has been developed. The resin was based on the reaction between low molecular weight epoxidised natural rubber and acrylic acid. When formulated with reactive monomers and photoinitiator, it solidified upon irradiation with UV light. The resin may find applications in coating for cellulosic-based substrates and pressure-sensitive adhesive

Preparation and Characterisation of Crosslinked Natural Rubber (SMR CV 60 and Epoxidised Natural Rubber (ENR-50 Blends

Directory of Open Access Journals (Sweden)

M. SASITARAN

2018-04-01

Full Text Available In this sudy, the influenceof di(tert-butylperoxyisopropylbenzene (DTBPIB on the properties of natural rubber (NR blend with epoxidized natural rubber (ENR was determined. Fourier transform infrared spectroscopy with attenuated total refletance analysis and gel content confired crosslinking occurred in the rubber blends in the presence of peroxide DTBPIB percentage. Studies including tensile properties, dynamic mechanical properties, thermogravimetric analysis (TGA and water absorptivity showed the changes in properties of the crosslinked NR/ENR blends. Tensile properties analysis disclosed the improvements in the modulus at 300% elongation and tensile stength with increasing NR ratios. Dynamic mechanical analysis revealed the blends to be incompatible and immiscible, with ENR showing a more viscous behaviour compared to the polymer blends. Thermal properties improved by blending NR with ENR as the onset temperature of NR/ENR: 50/50 was higher than pure NR by approximately 10oC and ENR by approximately 2oC. Water absorptivity experiment revealed a two-fold reduction in the presence of crosslinking for all blend ratios.

Silane grafted natural rubber and its compatibilization effect on silica-reinforced rubber tire compounds

NARCIS (Netherlands)

Sengloyluan, K.; Sahakaro, K.; Dierkes, W. K.; Noordermeer, J. W.M.

2017-01-01

Natural Rubber (NR) grafted with 3-octanoylthio-1-propyltriethoxysilane (NXT) was prepared by melt mixing using 1,1′-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane as initiator at 140 °C with NXT contents of 10 and 20 parts per hundred rubber [phr] and initiator 0.1 phr. The silane grafted on NR

Swelling behaviour of isora/natural rubber composites in oils used

Indian Academy of Sciences (India)

Natural rubber/isora fibre composites were cured at various temperatures. The solvent swelling characteristics of natural rubber composites containing both untreated and alkali treated fibres were investigated in aromatic and aliphatic solvents like toluene, and -hexane. The diffusion experiments were conducted by the ...

Preparation and properties of natural nanocomposites based on natural rubber and naturally occurring halloysite nanotubes

International Nuclear Information System (INIS)

Rooj, Sandip; Das, Amit; Thakur, Varun; Mahaling, R.N.; Bhowmick, Anil K.; Heinrich, Gert

2010-01-01

A 'green' composite based on natural halloysite nanotubes (HNTs) and natural rubber (NR) was prepared by mechanical mixing. A silane coupling agent, bis (triethoxysilylpropyl)-tetrasulphide, was utilized to enhance the properties of these composites. It was observed that the reinforcing activity of HNTs was superior to commercial silica coupled with the same amount of silane coupling agent. Moreover the on-set thermal degradation decomposition temperature was improved by ∼64 o C with the addition of 10 parts HNTs per hundred of rubber. Transmission electron microscopic images confirmed the good dispersion of the HNTs in the rubber matrix, whereas X-ray diffraction studies showed a little change in interlayer spacing between the two silicate layers of HNTs.

Preparation of irradiated natural rubber latex-styrene copolymer for electrical gloves

International Nuclear Information System (INIS)

Made Sumarti Kardha

2010-01-01

Research on irradiated natural rubber latex-styrene copolymer to prepare electrical glove have been done. Vulcanization of natural rubber latex (NRL) was done by mixing 2 phr (per hundred of rubber) of normal butyl acrylate (n-BA) emulsion then irradiated with ã-ray "6"0Co at the dose of 30 kGy producing irradiated natural rubber latex (INRL). Natural rubber latex-styrene copolymers (SC) were prepared by mixing NRL and styrene monomer at styrene concentrations of 50 phr, 75 phr, 100 phr, 500 phr and irradiated at the doses of 15 kGy, 30 kGy and 45 kGy, then characterized their latex and film properties to obtain optimum SC of SC50. This optimum SC, SC50 then mixed with IRNL at the weight ratio of 0/100, 30/70, 50/50, 70/30 and 100/0, to produce irradiated natural rubber latex-styrene copolymer. The properties of copolymer rubber films made by dipping process i.e., % conversion, total solid content, latex viscosity, tensile strength, modulus 300 %, elongation at break, electrical resistance and dielectric constant were then characterized. Characterization result showed that (INRL-SC50) with 50/50 ratio irradiated at the dose of 30 kGy, have % conversion of 80.93 %, electrical resistivity of 1.73 x 10"1"4 Ohm cm and dielectric constant of 2.76 which fulfill the requirement as material for electrical gloves. (author)

Survey of the rubber tree genome reveals a high number of cysteine protease-encoding genes homologous to Arabidopsis SAG12.

Science.gov (United States)

Zou, Zhi; Liu, Jianting; Yang, Lifu; Xie, Guishui

2017-01-01

Arabidopsis thaliana SAG12, a senescence-specific gene encoding a cysteine protease, is widely used as a molecular marker for the study of leaf senescence. To date, its potential orthologues have been isolated from several plant species such as Brassica napus and Nicotiana tabacum. However, little information is available in rubber tree (Hevea brasiliensis), a rubber-producing plant of the Euphorbiaceae family. This study presents the identification of SAG12-like genes from the rubber tree genome. Results showed that an unexpected high number of 17 rubber orthologues with a single intron were found, contrasting the single copy with two introns in Arabidopsis. The gene expansion was also observed in another two Euphorbiaceae plants, castor bean (Ricinus communis) and physic nut (Jatropha curcas), both of which contain 8 orthologues. In accordance with no occurrence of recent whole-genome duplication (WGD) events, most duplicates in castor and physic nut were resulted from tandem duplications. In contrast, the duplicated HbSAG12H genes were derived from tandem duplications as well as the recent WGD. Expression analysis showed that most HbSAG12H genes were lowly expressed in examined tissues except for root and male flower. Furthermore, HbSAG12H1 exhibits a strictly senescence-associated expression pattern in rubber tree leaves, and thus can be used as a marker gene for the study of senescence mechanism in Hevea.

Effect of concentrated epoxidised natural rubber and silica masterbatch for tyre application

Energy Technology Data Exchange (ETDEWEB)

Azira, A. A., E-mail: azira@lgm.gov.my; Kamal, M. M., E-mail: mazlina@lgm.gov.my [High Value Added Rubber Products and Nanostructured Materials, Stesen Penyelidikan RRIM, LGM 47000 Sungai Buloh, Selangor (Malaysia); Verasamy, D., E-mail: devaraj@lgm.gov.my [Environmental Technology & Sustainability, Technology & Engineering Division, Malaysian Rubber Board, Stesen Penyelidikan RRIM, LGM 47000 Sungai Buloh, Selangor (Malaysia)

2016-07-06

The availability of concentrated epoxidised natural rubber (ENR-LC) has provided a better opportunity for using epoxidised natural rubber (ENR) with silica to reinforce natural rubber for tyre application. ENR-LC mixed directly with silica to rubber by high speed stirrer without using any coupling agent. Some rubber compounds were prepared by mixing a large amount of precipitated amorphous white silica with natural rubber. The silica was prepared in aqueous dispersion and the filler was perfectly dispersed in the ENR-LC. The performance of the composites was evaluated in this work for the viability of ENR-LC/Si in tyre compounding. Compounding was carried out on a two roll mill, where the additives and curing agents was later mixed. Characterization of these composites was performed by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) for dispersion as well as mechanical testing. C-ENR/Si showed efficient as primary reinforcing filler in ENR with regard to modulus and tensile strength, resulting on an increase in the stiffness of the rubbers compared to ENR latex. Overall improvement in the mechanical properties for the ENR-LC over the control crosslinked rubber sample was probably due to synergisms of silica reinforcement and crosslinking of the polymeric matrix phase.

Effect of concentrated epoxidised natural rubber and silica masterbatch for tyre application

International Nuclear Information System (INIS)

Azira, A. A.; Kamal, M. M.; Verasamy, D.

2016-01-01

The availability of concentrated epoxidised natural rubber (ENR-LC) has provided a better opportunity for using epoxidised natural rubber (ENR) with silica to reinforce natural rubber for tyre application. ENR-LC mixed directly with silica to rubber by high speed stirrer without using any coupling agent. Some rubber compounds were prepared by mixing a large amount of precipitated amorphous white silica with natural rubber. The silica was prepared in aqueous dispersion and the filler was perfectly dispersed in the ENR-LC. The performance of the composites was evaluated in this work for the viability of ENR-LC/Si in tyre compounding. Compounding was carried out on a two roll mill, where the additives and curing agents was later mixed. Characterization of these composites was performed by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) for dispersion as well as mechanical testing. C-ENR/Si showed efficient as primary reinforcing filler in ENR with regard to modulus and tensile strength, resulting on an increase in the stiffness of the rubbers compared to ENR latex. Overall improvement in the mechanical properties for the ENR-LC over the control crosslinked rubber sample was probably due to synergisms of silica reinforcement and crosslinking of the polymeric matrix phase.

Protecting tropical forests from the rapid expansion of rubber using carbon payments.

Science.gov (United States)

Warren-Thomas, Eleanor M; Edwards, David P; Bebber, Daniel P; Chhang, Phourin; Diment, Alex N; Evans, Tom D; Lambrick, Frances H; Maxwell, James F; Nut, Menghor; O'Kelly, Hannah J; Theilade, Ida; Dolman, Paul M

2018-03-02

Expansion of Hevea brasiliensis rubber plantations is a resurgent driver of deforestation, carbon emissions, and biodiversity loss in Southeast Asia. Southeast Asian rubber extent is massive, equivalent to 67% of oil palm, with rapid further expansion predicted. Results-based carbon finance could dis-incentivise forest conversion to rubber, but efficacy will be limited unless payments match, or at least approach, the costs of avoided deforestation. These include opportunity costs (timber and rubber profits), plus carbon finance scheme setup (transaction) and implementation costs. Using comprehensive Cambodian forest data, exploring scenarios of selective logging and conversion, and assuming land-use choice is based on net present value, we find that carbon prices of $30-$51 per tCO 2 are needed to break even against costs, higher than those currently paid on carbon markets or through carbon funds. To defend forests from rubber, either carbon prices must be increased, or other strategies are needed, such as corporate zero-deforestation pledges, and governmental regulation and enforcement of forest protection.

Verification of Interactions between Silica and Epoxidized Squalene as a Model for Epoxidized Natural Rubber

NARCIS (Netherlands)

Kaewsakul, Wisut; Sahakaro, Kannika; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

2014-01-01

Unmodified squalene (Sq) and epoxidised squalene (ESq), as models for natural rubber and epoxidised natural rubber, were mixed with silica in a reactor at 140 – 145ºC, which corresponds to the optimal mixing dump temperature of silica-filled natural rubber or epoxidised natural rubber compounds. The

Application of gamma irradiation for incorporation of rubber powder in the formulations of EPDM and natural rubber

International Nuclear Information System (INIS)

Kiyan, Ludmila Y.P.; Parra, Duclerc Fernandes; Lugao, Ademar Benevolo

2013-01-01

The objective of this work was to study the behavior of the recycling of rubber burrs in form of powder, of the rubber industry from EPDM rubber powder and natural rubber with SBR. The rubber powder was irradiated and reused in rubber artifacts formulations for classical vulcanization. The processed material was irradiated using a 60 Co source in doses of 50, 100, 150 and 200 kGy and a dose rate of 5 kGy s-1 at room temperature. The radiation created devulcanization active sites for subsequent integration of the material (rubber powder) in formulations of commercial use. The processes were compared and their products characterized by analytical methods of the physical properties such as strength and elongation. Satisfactory results were found, noting a major spin-off of EPDM chain demonstrated by increased elongation

Reinforcement of natural rubber/high density polyethylene blends with electron beam irradiated liquid natural rubber-coated rice husk

Energy Technology Data Exchange (ETDEWEB)

Chong, E.L.; Ahmad, Ishak [Polymer Research Center (PORCE), School of Chemical Science and Food Technology, Universiti Kebangsaan Malaysia 4, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia); Dahlan, H.M. [Radiation Processing Technology Division, Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang, Selangor Darul Ehsan (Malaysia); Abdullah, Ibrahim, E-mail: dia@ukm.m [Polymer Research Center (PORCE), School of Chemical Science and Food Technology, Universiti Kebangsaan Malaysia 4, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia)

2010-08-15

Coating of rice husk (RH) surface with liquid natural rubber (LNR) and exposure to electron beam irradiation in air were studied. FTIR analysis on the LNR-coated RH (RHR) exposed to electron beam (EB) showed a decrease in the double bonds and an increase in hydroxyl and hydrogen bonded carbonyl groups arising from the chemical interaction between the active groups on RH surface with LNR. The scanning electron micrograph showed that the LNR formed a coating on the RH particles which transformed to a fine and clear fibrous layer at 20 kGy irradiation. The LNR film appeared as patches at 50 kGy irradiation due to degradation of rubber. Composites of natural rubber (NR)/high density polyethylene (HDPE)/RHR showed an optimum at 20-30 kGy dosage with the maximum stress, tensile modulus and impact strength of 6.5, 79 and 13.2 kJ/m{sup 2}, respectively. The interfacial interaction between the modified RH and TPNR matrix had improved on exposure of RHR to e-beam at 20-30 kGy dosage.

Morpho-Molecular Characterization of Two Ampelomyces spp. (Pleosporales) Strains Mycoparasites of Powdery Mildew of Hevea brasiliensis.

Science.gov (United States)

Liyanage, Kapila K; Khan, Sehroon; Brooks, Siraprapa; Mortimer, Peter E; Karunarathna, Samantha C; Xu, Jianchu; Hyde, Kevin D

2018-01-01

Powdery mildew disease of rubber affects immature green leaves, buds, inflorescences, and other immature tissues of rubber trees, resulting in up to 45% losses in rubber latex yield worldwide. The disease is often controlled by dusting the diseased plants with powdered sulfur, which can have long-term negative effects on the environment. Therefore, it is necessary to search for alternative and environmentally friendly control methods for this disease. This study aimed to identify mycoparasites associated with rubber powdery mildew species, and characterize them on the basis of morpho-molecular characteristics and phylogenetic analyses of ITS rDNA regions. We observed that the Ampelomyces fungus parasitizes rubber powdery mildew, and eventually destroys it. Furthermore, on the basis of phylogenetic analyses and morphological characteristics we confirmed that the Ampelomyces mycoparasite isolated from rubber powdery mildew is closely related to other mycohost taxa in the Erysiphe genus. A total of 73 (71 retrieved from GenBank and two obtained from fresh collections of rubber powdery mildew fungi) Ampelomyces spp. were analyzed using ITS rDNA sequences and 153 polymorphic sites were identified through haplotypic analyses. A total of 28 haplotypes (H1-H28) were identified to have a complex network of mutation events. The results from phylogenetic tree constructed on the basis of maximum likelihood analyses, and the haplotype network tree revealed similar relationships of clustering pattern. This work presents the first report on morpho-molecular characterization of Ampelomyces species that are mycoparasites of powdery mildew of Hevea brasiliensis .

Optimization of oil yield from Hevea brasiliensis seeds through ultrasonic-assisted solvent extraction via response surface methodology

Directory of Open Access Journals (Sweden)

Val Irvin F. Mabayo

2018-01-01

Full Text Available The demand for oil has been increasing vastly over time, and the source of this has slowly been diminishing. The use of non-food feedstock is seen as a promising alternative source for the production of bio-based fuel. In this study, rubber (Hevea brasiliensis seeds were utilized as biomass in bio-oil production considering that these are non-edible and considered wastes in rubber tree plantations. In the oil extraction process, the rubber seed kernels were oven dried at 100 °C for 24 h, powdered and then dried further at 105 °C for 4 h. After characterization, optimization study was done using Design Expert 7.0 software through central composite design of the response surface methodology. Ultrasonication technology was employed in the oil extraction process which significantly reduced the reaction time needed for extraction to 15 min compared the conventional extraction method of at least 8 h. An optimum rubber seed oil (RSO yield of 30.3 ± 0.3% was obtained using 15 g biomass, 5:1 n-hexane to biomass (mL g−1 ratio, 50 μm resonance amplitude and 60 ± 5 °C temperature at 15 min reaction time. The oil yield at optimum condition was found to have 0.89 g mL−1 density at room temperature, 26.7 cSt kinematic viscosity at 40 °C and high heating value of 39.2 MJ kg−1. The Fourier Transform Infrared Radiation spectroscopy analysis of the RSO, at optimum condition, showed the presence of carboxylic acid and ester carbonyl functional groups which are good indicators as a potential source of biodiesel. Keywords: Hevea brasiliensis, Oil extraction, Optimization, Response surface methodology, Rubber seed oil, Ultrasonic-assisted solvent extraction

Studies on Hydrogenation of Liquid Natural Rubber Using Diimide

Directory of Open Access Journals (Sweden)

Nur Hanis Adila Azhar

2015-01-01

Full Text Available Liquid natural rubber (LNR is a depolymerized natural rubber (NR which consists of shorter polymeric chains and lower molecular weight (Mw90% was achieved by manipulating the reaction parameters such as sources of diimide, TSH concentration, solvent, and reaction time. The optimum condition was 3 : 1 weight ratio of TSH/LNR in o-xylene at 130°C in 4-hour reaction period.

Microwave pre-heating of natural rubber using a rectangular wave guide (MODE: TE10

Directory of Open Access Journals (Sweden)

Doo-ngam, N.

2007-11-01

Full Text Available This paper presents an application of microwave radiation for pre-heating of natural rubbercompounding with various sulphur contents. The natural rubber-compounding was pre-heated by microwave radiation using a rectangular wave guide system (MODE: TE10 operating at frequency of 2.45 GHz in which the power can vary from 0 to 1500 W. In the present work, the influence of power input, sample thickness, and sulphur content were examined after applying microwave radiation to the rubber samples. Results are discussed regarding the thermal properties, 3-D network, dielectric properties and chemical structures. From the result, firstly, it was found that microwave radiation can be applied to pre-heating natural rubber-compounding before the vulcanization process. Secondly, microwave radiation was very useful for pre-heating natural rubber-compounding that has a thickness greater than 5mm. Thirdly, crosslinking in natural rubber-compounding may occurs after pre-heating by microwave radiation though Fourier Transform Infrared Spectroscopy(FTIR. Finally, there a little effect of sulphur content on temperature profiles after applying microwave radiation to the natural rubber-compounding. Moreover, natural rubber-compounding without carbon black showed a lower heat absorption compared with natural rubbercompounding filled carbon black. This is due to the difference in dielectric loss factor. This preliminary result will be useful information in terms of microwave radiation for pre-heating natural rubber-compounding and rubber processing in industry.

Variation of Soil Bacterial Communities in a Chronosequence of Rubber Tree (Hevea brasiliensis Plantations

Directory of Open Access Journals (Sweden)

Yu-Jie Zhou

2017-05-01

Full Text Available Regarding rubber tree plantations, researchers lack a basic understanding of soil microbial communities; specifically, little is known about whether or not soil microbial variation is correlated with succession in these plantations. In this paper, we used high-throughput sequencing of the 16S rRNA gene to investigate the diversity and composition of the soil bacterial communities in a chronosequence of rubber tree plantations that were 5, 10, 13, 18, 25, and 30 years old. We determined that: (1 Soil bacterial diversity and composition show changes over the succession stages of rubber tree plantations. The diversity of soil bacteria were highest in 10, 13, and 18 year-old rubber tree plantations, followed by 30 year-old rubber tree plantations, whereas 5 and 25 year-old rubber tree plantations had the lowest values for diversity. A total of 438,870 16S rDNA sequences were detected in 18 soil samples from six rubber tree plantations, found in 28 phyla, 66 classes, 139 orders, 245 families, 355 genera, and 645 species, with 1.01% sequences from unclassified bacteria. The dominant phyla were Acidobacteria, Proteobacteria, Chloroflexi, Actinobacteria, and Verrucomicrobia (relative abundance large than 3%. There were differences in soil bacterial communities among different succession stages of rubber tree plantation. (2 Soil bacteria diversity and composition in the different stages was closely related to pH, vegetation, soil nutrient, and altitude, of which pH, and vegetation were the main drivers.

Resistance of treated rubber wood ( Hevea brasiliensis ) to termite ...

African Journals Online (AJOL)

Spent rubber trees from a 25 year old plantation were cut, sawn and treated with Copper Chromium Arsenate (CCA) and Cashew Nut Shell Liquid (CNSL). Two sets of wood samples were treated with CCA and CNSL respectively while the third set was not treated to serve as control. The three sets were exposed to termite ...

Rheological behavior of raw natural rubber coagulated by microorganisms

Directory of Open Access Journals (Sweden)

Zhifen Wang

2014-01-01

Full Text Available Tests of the strain sweep, frequency sweep and stress relaxation for raw natural rubber coagulated by microorganisms (NR-m and raw natural rubber coagulated by acid (NR-a were carried out with the use of a rubber process analyzer (RPA. The results showed that the storage torque, complex viscosity of NR-m were higher than those of NR-a while the loss factor was lower. The effect of temperature on viscosity of raw NR was studied following the Arrhenious-Frenkel-Eyring model. The viscous flow behavior of NR-m was poorer than those of NR-a. Furthermore, stress relaxation measurements of raw NR showed a longer period of relaxation for NR-m.

WET AND DRY SEASON ECOSYSTEM LEVEL FLUXES OF ISOPRENE AND MONOTERPENES FROM A SOUTHEAST ASIAN SECONDARY FOREST AND RUBBER TREE PLANTATION

Science.gov (United States)

Canopy scale fluxes of isoprene and monoterpenes were investigated in both wet and dry seasons above a rubber tree (Hevea brasiliensis)/secondary tropical forest in the Yunnan province of southwestern China. Drought conditions were unusually high during the dry season experiment....

Synthesis, characterization and degradation behavior of admicelled polyacrylate-natural rubber

International Nuclear Information System (INIS)

Pongpilaipruet, Angkana; Magaraphan, Rathanawan

2015-01-01

In order to improve weatherability of the cured natural rubber, the novel introduction of good ozone resistant polymers such as polyacrylates (poly(methyl acrylate) (PMA) or poly(methyl methacrylate) (PMMA)) into natural rubber (NR) by admicellar polymerization was investigated in this work. The admicellar polymerization to synthesize polyacrylate layer over the surface of NR latex particles was performed with varying monomer type (PMA and PMMA) and content (50 and 100 mM). The admicelled PMMA showed higher molecular weight than PMA. Fourier transform infrared spectra of the admicellar synthesized natural rubbers exhibited characteristic peaks of those polyacrylates. Micrographs from transmission electron and field emission scanning electron microscopes (FE-SEM) revealed the coatings of PMA and PMMA over the rubber particles, suggesting a core-shell structure. Thermogravimetric analysis revealed that the admicelled rubbers not only showed an improvement in heat stability but also a single decomposition temperature. After vulcanization, FE-SEM results showed the cured admicelled rubbers had phase transformation from core-shell to phase separation (aggregate domains of polyacrylate-rich phase) with smooth interface. This agreed well to their one glass transition temperature (∼−48 °C) which indicated good miscibility between NR and each polyacrylate. The cracks generated after exposure to ozone found in the admicelled rubbers were smaller than those in NR, suggesting better ozone resistance was achieved. Increasing monomer concentration led to less cracks or much better ozone resistance. Furthermore, changes in mechanical properties after ozone exposure of the admicelled PMA-NR were less than those of the admicelled PMMA-NR (having the same shell content) and the NR, respectively. - Highlights: • We use admicellar technique to add polyacrylates to NR in form of core-shell rubber. • This core-shell structure was physically formed as seen by the phase

Synthesis, characterization and degradation behavior of admicelled polyacrylate-natural rubber

Energy Technology Data Exchange (ETDEWEB)

Pongpilaipruet, Angkana; Magaraphan, Rathanawan, E-mail: rathanawan.k@chula.ac.th

2015-06-15

In order to improve weatherability of the cured natural rubber, the novel introduction of good ozone resistant polymers such as polyacrylates (poly(methyl acrylate) (PMA) or poly(methyl methacrylate) (PMMA)) into natural rubber (NR) by admicellar polymerization was investigated in this work. The admicellar polymerization to synthesize polyacrylate layer over the surface of NR latex particles was performed with varying monomer type (PMA and PMMA) and content (50 and 100 mM). The admicelled PMMA showed higher molecular weight than PMA. Fourier transform infrared spectra of the admicellar synthesized natural rubbers exhibited characteristic peaks of those polyacrylates. Micrographs from transmission electron and field emission scanning electron microscopes (FE-SEM) revealed the coatings of PMA and PMMA over the rubber particles, suggesting a core-shell structure. Thermogravimetric analysis revealed that the admicelled rubbers not only showed an improvement in heat stability but also a single decomposition temperature. After vulcanization, FE-SEM results showed the cured admicelled rubbers had phase transformation from core-shell to phase separation (aggregate domains of polyacrylate-rich phase) with smooth interface. This agreed well to their one glass transition temperature (∼−48 °C) which indicated good miscibility between NR and each polyacrylate. The cracks generated after exposure to ozone found in the admicelled rubbers were smaller than those in NR, suggesting better ozone resistance was achieved. Increasing monomer concentration led to less cracks or much better ozone resistance. Furthermore, changes in mechanical properties after ozone exposure of the admicelled PMA-NR were less than those of the admicelled PMMA-NR (having the same shell content) and the NR, respectively. - Highlights: • We use admicellar technique to add polyacrylates to NR in form of core-shell rubber. • This core-shell structure was physically formed as seen by the phase

The SWEET gene family in Hevea brasiliensis - its evolution and expression compared with four other plant species.

Science.gov (United States)

Sui, Jin-Lei; Xiao, Xiao-Hu; Qi, Ji-Yan; Fang, Yong-Jun; Tang, Chao-Rong

2017-12-01

SWEET proteins play an indispensable role as a sugar efflux transporter in plant development and stress responses. The SWEET genes have previously been characterized in several plants. Here, we present a comprehensive analysis of this gene family in the rubber tree, Hevea brasiliensis . There are 36 members of the SWEET gene family in this species, making it one of the largest families in plant genomes sequenced so far. Structure and phylogeny analyses of these genes in Hevea and in other species demonstrated broad evolutionary conservation. RNA-seq analyses revealed that SWEET2, 16, and 17 might represent the main evolutionary direction of SWEET genes in plants. Our results in Hevea suggested the involvement of HbSWEET1a , 2e , 2f , and 3b in phloem loading, HbSWEET10a and 16b in laticifer sugar transport , and HbSWEET9a in nectary-specific sugar transport. Parallel studies of RNA-seq analyses extended to three other plant species ( Manihot esculenta , Populus trichocarpa , and Arabidopsis thaliana ) produced findings which implicated MeSWEET10a, 3a, and 15b in M. esculenta storage root development, and the involvement of PtSWEET16b and PtSWEET16d in P. trichocarpa xylem development. RT-qPCR results further revealed that HbSWEET10a, 16b, and 1a play important roles in phloem sugar transport. The results from this study provide a foundation not only for further investigation into the functionality of the SWEET gene family in Hevea, especially in its sugar transport for latex production, but also for related studies of this gene family in the plant kingdom.

Progress in radiation vulcanization of natural rubber latex

International Nuclear Information System (INIS)

Makuuchi, Keizo

2000-01-01

Vulcanization dose defined as the radiation dose at which cross-linked natural rubber in latex has the maximum tensile strength can be reduced by adding carbon tetrachloride as a reaction accelerator. The radiation vulcanization of natural rubber latex was selected as one of regional projects of IAEA in 1989 and a pilot plant was built in Jakarta. The products from it were evaluated during 1983-1985, followed by IAEA decision to support the continued R and D study at Takasaki, JAERI. Various factors to improve the properties of the products have been studied. Several advantages of the process over conventional method, such as absence of N-nitrosoamines, low cytotoxicity, decomposability in the environment, transparency and softness, were confirmed. The technology has been transferred toward commercial application in Thailand, and pilot plants being set up in Indonesia, India, Malaysia and Thailand. Moreover, the process was found to be effective in reducing protein remaining in natural rubber latex products and the initial investment and irradiation cost was found to be greatly reduced by employing low energy electron accelerator. This paper reviews such progress. (S. Ohno)

Thermal analysis and microstructure of hexaperrite based magnet composite with natural rubber matrix

International Nuclear Information System (INIS)

Sudirman; Ridwan; Jamilah; Trijono, Waluyo

2000-01-01

Thermal and microstructure analyse of hexa ferrite based on composite magnets with natural rubber matrix have been done to investigate their performance. Such magnets play an important role in the toy and house-hold industries because of their suitable magnetic properties, low cost, lightness and flexibility. The composite magnets were synthesized by blending the ferrite powder and natural rubber at composition 30%-70% rubber volume. The microstructure and thermal behaviour of the composite were examined by using SEM and OTA/TGA. The result show that the natural rubber swelling is optimally at 181,17 o C, which is the recommended top condition for blending. The performance magnet composite is limited by the change of natural rubber properties which decompose at temperature around 400 o C. In the decomposition process, the natural rubber molecule trapped in a composite system based on BaM is more difficult are more compared to the composite system based on SrM because the BaM system particle microstructure and its distribution more homogeneous

Radiation vulcanization of Philippine natural rubber latex

International Nuclear Information System (INIS)

Dela Rosa, Alumanda M.; Abad, Lucille V.; Sta, Lorna P.; Ana-Relleve; Tranquilan-Aranilla, Charito O.; Pascual, Cristina L.

1996-01-01

The response of Philippine natural rubber latex to radiation vulcanization and the stability of the irradiated natural rubber latex (INRL) upon storage and aging were investigated. Commercially available high ammonia (HA) concentrated lattices obtained from various rubber plantations in Mindanao Island were treated with 5 phr of n-butyl acrylate (nBA), and gamma-irradiated at the PNRI sup 60 Co irradiation facility at dose rate of 2.57 KGy/hr. Unirradiated cast latex films gave different green strength which varied from 2 - 11 MPa. Cast films from INRL exhibited maximum tensile strengths of 25 - 32 MPa at a radiation dose of 15 kGy. Higher tensile strengths were obtained from cast films with low Mg and high nitrogen contents. Thermal analysis using thermogravimetry (TG) revealed one major decomposition product at 374 degree C - 377 degree C. Its rate of decomposition decreased to a minimum at 15 kGy, then increased as radiation dose increased. This trend correlated well with the tensile strength measurements. The stability of the INRL upon storage and aging is an essential parameter to the rubber latex industry. For storage studies, INRL was stored for various periods of time. It was found that the pH and total solids content of the stored INRL did not change significantly after 12 months of storage; the MST values remained at above 100 seconds, and the viscosity decreased with time. The cast films exhibited a decline in tensile strength, modulus 300% and crosslinking density upon storage. While there were observed changes in the physical properties of the IRNL during the storage period, the data indicate that these properties were within values acceptable to the latex industry. Tests on the aging properties of INRL film were undertaken. It was shown that among the chemical antioxidants presently used by the latex industry. TNPP demonstrated the highest antioxidant property, followed by Antage DAHQ and Vulcanox BKF. Our data indicate that the natural rubber latex

Soil Carbon Stocks Decrease following Conversion of Secondary Forests to Rubber (Hevea brasiliensis) Plantations

Science.gov (United States)

de Blécourt, Marleen; Brumme, Rainer; Xu, Jianchu; Corre, Marife D.; Veldkamp, Edzo

2013-01-01

Forest-to-rubber plantation conversion is an important land-use change in the tropical region, for which the impacts on soil carbon stocks have hardly been studied. In montane mainland southeast Asia, monoculture rubber plantations cover 1.5 million ha and the conversion from secondary forests to rubber plantations is predicted to cause a fourfold expansion by 2050. Our study, conducted in southern Yunnan province, China, aimed to quantify the changes in soil carbon stocks following the conversion from secondary forests to rubber plantations. We sampled 11 rubber plantations ranging in age from 5 to 46 years and seven secondary forest plots using a space-for-time substitution approach. We found that forest-to-rubber plantation conversion resulted in losses of soil carbon stocks by an average of 37.4±4.7 (SE) Mg C ha−1 in the entire 1.2-m depth over a time period of 46 years, which was equal to 19.3±2.7% of the initial soil carbon stocks in the secondary forests. This decline in soil carbon stocks was much larger than differences between published aboveground carbon stocks of rubber plantations and secondary forests, which range from a loss of 18 Mg C ha−1 to an increase of 8 Mg C ha−1. In the topsoil, carbon stocks declined exponentially with years since deforestation and reached a steady state at around 20 years. Although the IPCC tier 1 method assumes that soil carbon changes from forest-to-rubber plantation conversions are zero, our findings show that they need to be included to avoid errors in estimating overall ecosystem carbon fluxes. PMID:23894456

Particle reinforced composites from acrylamide modified blend of styrene-butadiene and natural rubber

Science.gov (United States)

Blends of styrene-butadiene rubber and natural rubber that provide balanced properties were modified with acrylamide and reinforced with soy protein particles. The rubber composites show improved mechanical properties. Both modified rubber and composites showed a faster curing rate. The crosslinking...

Design of Self-Healing Supramolecular Rubbers by Introducing Ionic Cross-Links into Natural Rubber via a Controlled Vulcanization.

Science.gov (United States)

Xu, Chuanhui; Cao, Liming; Lin, Baofeng; Liang, Xingquan; Chen, Yukun

2016-07-13

Introducing ionic associations is one of the most effective approaches to realize a self-healing behavior for rubbers. However, most of commercial rubbers are nonpolar rubbers without now available functional groups to be converted into ionic groups. In this paper, our strategy was based on a controlled peroxide-induced vulcanization to generate massive ionic cross-links via polymerization of zinc dimethacrylate (ZDMA) in natural rubber (NR) and exploited it as a potential self-healable material. We controlled vulcanization process to retard the formation of covalent cross-link network, and successfully generated a reversible supramolecular network mainly constructed by ionic cross-links. Without the restriction of covalent cross-linkings, the NR chains in ionic supramolecular network had good flexibility and mobility. The nature that the ionic cross-links was easily reconstructed and rearranged facilitating the self-healing behavior, thereby enabling a fully cut sample to rejoin and retain to its original properties after a suitable self-healing process at ambient temperature. This study thus demonstrates a feasible approach to impart an ionic association induced self-healing function to commercial rubbers without ionic functional groups.

Hermaphroditism in the rubber tree Hevea brasiliensis (Willd. ex Adr. de Juss. Muell. Arg. - II

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Silvia Marina Cuco

1998-12-01

Full Text Available Flowers of three Hevea brasiliensis clones, RRIM 527, RRIM 600 and GT 1, were analyzed under stereomicroscope and scanning electron microscope, aiming to observe hermaphroditism rates. Results showed 71.49% hermaphrodite flowers, 29.83% of which exhibited incompletely developed, residual anthers. The scanning electron microscope analysis did not detect differences in anther epidermis of male and bisexual flowers of RRIM 600 and RRIM 527. In GT 1 clone (sterile male, the anther epidermis was already weak at the beginning of floral development and completely wrinkled at the end of maturation. Consequently, the anthers were empty by this stage.Flores de três clones de Hevea brasiliensis, RRIM 527, RRIM 600 e GT 1, foram analisadas, sob lupa e microscopia eletrônica de varredura, a fim de se observar as taxas de ocorrência de hermafroditismo. Os resultados mostraram um total de 71,49% de flores hermafroditas, sendo que destas 29,83% apresentaram anteras residuais, não completamente desenvolvidas. As análises ao microscópio de varredura não mostraram diferença ao nível de epiderme de anteras em flores masculinas e hermafroditas de RRIM 527 e RRIM 600. No clone GT 1 (macho estéril a epiderme das anteras mostrou-se frouxa já no início do desenvolvimento floral e completamente enrugada ao final da maturação, demonstrando que as anteras estão vazias neste estádio.

Radiation processing of natural rubber and its applications

International Nuclear Information System (INIS)

Dahlan Hj. Mohd

2007-01-01

Research in natural rubber (NR) is still offering good and exciting opportunities especially in making NR into superior products and as a source for new chemicals by modification of its structure. As in the case of liquid epoxidised natural rubber acrylic (LENRA), it has been shown that it has the ability to induce the interfacial interaction between NR and polyolefin i.e. High-density polyethylene (HDPE) as demonstrated by Transmission Electron Microscopy (TEM) and small angle neutron scattering (SANS) techniques. For NR/HDPE blend, without deuteration technique, SANS was also to induce some scattering data leading to fruitful information on the interfacial interaction between the blend compositions. (author)

Electron beam cross-linking of natural rubber/linear-low density polyethylene blends

International Nuclear Information System (INIS)

Ahmad, A.; Mohd, D. H.; Abdullah, I.

2005-01-01

Effects of electron beam irradiation on the mechanical properties and morphological structure of natural rubber/linear-low density polyethylene blend was investigated The natural rubber/linear-low density polyethylene blend was prepared by melt blending in a Haake internal mixer at 140 d ig C , rotor speed of 50 rpm, and in 15 min Liquid natural rubber was incorporated into the blend as a compatibilizer Samples in the form of 1 mm sheets were exposed to 50-300 kGy of electron beam irradiation and analyzed for swelling index and gel content, tensile strength, and surface morphology. The result Indicated that gel content and mechanical properties of the samples increased with radiation dosage. The honey-comb structure of the surface morphology in low dosage irradiated samples slowly transformed into a continuous matrix on increasing radiation dose The variation of mechanical and physical properties was due to Increase in cross-linking density in the rubber and plastic phases and rubber-plastic Interaction on irradiation

Natural rubber/nitrile butadiene rubber/hindered phenol composites with high-damping properties

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Xiuying Zhao

2015-10-01

Full Text Available New natural rubber (NR/nitrile butadiene rubber (NBR/hindered phenol (AO-80 composites with high-damping properties were prepared in this study. The morphological, structural, and mechanical properties were characterized by atomic force microscopy (AFM, polarized Fourier transform infrared spectrometer (FTIR, dynamic mechanical thermal analyzer (DMTA, and a tensile tester. Each composite consisted of two phases: the NR phase and the NBR/AO-80 phase. There was partial compatibility between the NR phase and the NBR/AO-80 phase, and the NR/NBR/AO-80 (50/50/20 composite exhibited a co-continuous morphology. Strain-induced crystallization occurred in the NR phase at strains higher than 200%, and strain-induced orientation appeared in the NBR/AO-80 phase with the increase of strain from 100% to 500%. The composites had a special stress–strain behavior and mechanical properties because of the simultaneous strain-induced orientation and strain-induced crystallization. In the working temperature range of a seismic isolation bearing, the composites (especially the NR/NBR/AO-80 (50/50/20 composite presented a high loss factor, high area of loss peak (TA, and high hysteresis energy. Therefore, the NR/NBR/AO-80 rubber composites are expected to have important application as a high-performance damping material for rubber bearing.

Decomposition of the Rubber Tree Hevea brasiliensis Litter at Two Depths Descomposición del Mantillo del Árbol del Caucho Hevea brasiliensis en Dos Profundidades

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Thiago Claudino Gréggio

2008-06-01

Full Text Available The decomposition of soil litter contributes to maintaining agricultural sustainability, since the nutrients released by microbial activity are determinants of the net productivity of the agroecosystem. The decomposition of rubber tree (Hevea brasiliensis [Willd. ex A. Juss.] Müll. Arg. leaves located on the surface and buried in at 10 cm depth in Forest and Savannah (Cerradão soils (Oxisols was studied, with emphasis on the production of CO2 and the monthly variation of the remaining amounts of litter mass, soluble substances, cellulose and lignin. To evaluate CO2 production, H. brasiliensis leaves were incubated for 30 days in soils from the 0-2 cm and 10-12 cm layers. CO2 production increased in the 0-2 cm layer in comparison to the 10-12 cm layer. Litter mass and soluble substance loss was of 62 and 72% at the end of nine months of incubation, and of 38 and 65%, respectively, in the first three months, being greater in the deeper (71-74% than in surface layer (48-55%. Forest soil stimulated more litter mass loss and cellulose decomposition (only in the surface layer than Savannah soil. The cellulose (25% content decreased and lignin (30% increased in the initial months of incubation, however, at the end of the period of this study the same content (29% was found.La descomposición del mantillo del suelo contribuye a mantener la sostenibilidad agrícola, puesto que los nutrientes liberados por la actividad microbiana son determinantes para la productividad del ecosistema. La descomposición de hojas del árbol del caucho (Hevea brasiliensis [Willd. ex A. Juss.] Müll. Arg. colocadas en la superficie y enterradas en la profundidad de 10 cm en los suelos de Bosque y Cerradão (Oxisols se estudió con énfasis en la producción de CO2 y la variación mensual de las cantidades remanentes de masa foliar (MF, substancias solubles (SS, celulosa y lignina. Para evaluar la producción de CO2, se incubaron hojas del H. brasiliensis por 30 días en

Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

Energy Technology Data Exchange (ETDEWEB)

Xu, Tiwen [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Jia, Zhixin, E-mail: zxjia@scut.edu.cn [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Luo, Yuanfang; Jia, Demin [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Peng, Zheng [Agricultural Product Processing Research Institute, Chinese Academy of Tropical Agriculture Sciences, Zhanjiang 524001 (China)

2015-02-15

Highlights: • Substantiate the ring open reaction between Si-OH of silica and epoxy groups of ENR. • ENR can act as a bridge between NR and silica to enhance the interfacial interaction. • As a modifier, ENR gets the potential to be used in the tread of green tire for improving the wet skid resistance apparently. - Abstract: The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress–strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

Silica Based Superhydrophobic Nanocoatings for Natural Rubber Surfaces

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Veromee Kalpana Wimalasiri

2017-01-01

Full Text Available Silica based nonfluorinated superhydrophobic coatings for natural rubber surfaces have been developed. The coating was synthesized using nanosilica dispersion and a polychloroprene type binder as a compatibilizer. This nanocoating of silica was applied on to the surface of finished natural rubber gloves, by spray coating or dipped coating methods. The nanocoating demonstrates a water contact angle of more than 150° and sliding angle of 7°. The morphological features of the coating have been studied using scanning electron microscopy and atomic force microscopy while Fourier transform infrared spectroscopy was used to understand the nature of surface functional groups. Both imaging techniques provided evidence for the presence of nanosized particles in the coating. Coated gloves demonstrated comparable mechanical properties and significantly better alcohol resistivity when compared to those of the uncoated gloves.

Development of rubber-enriched dandelion varieties by metabolic engineering of the inulin pathway.

Science.gov (United States)

Stolze, Anna; Wanke, Alan; van Deenen, Nicole; Geyer, Roland; Prüfer, Dirk; Schulze Gronover, Christian

2017-06-01

Natural rubber (NR) is an important raw material for a large number of industrial products. The primary source of NR is the rubber tree Hevea brasiliensis, but increased worldwide demand means that alternative sustainable sources are urgently required. The Russian dandelion (Taraxacum koksaghyz Rodin) is such an alternative because large amounts of NR are produced in its root system. However, rubber biosynthesis must be improved to develop T. koksaghyz into a commercially feasible crop. In addition to NR, T. koksaghyz also produces large amounts of the reserve carbohydrate inulin, which is stored in parenchymal root cell vacuoles near the phloem, adjacent to apoplastically separated laticifers. In contrast to NR, which accumulates throughout the year even during dormancy, inulin is synthesized during the summer and is degraded from the autumn onwards when root tissues undergo a sink-to-source transition. We carried out a comprehensive analysis of inulin and NR metabolism in T. koksaghyz and its close relative T. brevicorniculatum and functionally characterized the key enzyme fructan 1-exohydrolase (1-FEH), which catalyses the degradation of inulin to fructose and sucrose. The constitutive overexpression of Tk1-FEH almost doubled the rubber content in the roots of two dandelion species without any trade-offs in terms of plant fitness. To our knowledge, this is the first study showing that energy supplied by the reserve carbohydrate inulin can be used to promote the synthesis of NR in dandelions, providing a basis for the breeding of rubber-enriched varieties for industrial rubber production. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Analysis of Gel Permeation Chromatography From Irradiation Copolymer Grafting of Methylmethacrylate on to Natural Rubber

International Nuclear Information System (INIS)

Hendrana, Sunit; Purwanto, Indratmoko Hari; Karyaningsih, Ipit; Utama, MargaHerwinarni

2004-01-01

Grafting of methyl methacrylate (MMA) onto natural rubber was carried out by γ-irradiation using 60 Co source at dose rate 1 KGy/h and total dose of 5 KGy. Gel permeation chromatography (GPC) was used to analyse the grafting. The GPC's chromatogram, molecular weight and molecular weight distribution data indicate that grafting of MMA onto natural rubber and homo polymerization of MMA are the reaction mostly occurs. Meanwhile, the presence of natural rubber radical with a chain end natural rubber radical affect the PMMA homopolymer occurred

Antifungal property of chili, shallot and garlic extracts against pathogenic fungi, Phomopsis spp., isolated from infected leaves of para rubber (Hevea brasiliensis Muell. Arg.

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Patcharawan Sittisart

2017-12-01

Full Text Available The aim of this study was to evaluate the antifungal property of extracts of chili, shallot and garlic (local varieties in Sisaket, Thailand against pathogenic fungi, Phomopsis spp., which were isolated from infected leaves of para rubber (Hevea brasiliensis Muell. Arg.. Seven isolates of Phomopsis spp. namely Phomopsis sp. SSK1.1, SSK1.2, SSK3.1, SSK4.1, SSK5.1, SSK5.2 and SSK7.1 were identified on the basis of morphological characteristics. Fresh plants were extracted with water to obtain crude extracts and their antifungal properties were tested on potato dextrose agar (PDA media. The study demonstrated that increasing the concentrations (20%, 40%, 60% or 80% of the chili extract exhibited a dependent increase in the inhibitory level on mycelial growth of Phomopsis spp. SSK3.1, SSK4.1 and SSK5.2. The inhibitory level on mycelial growth of shallot extract also increased in a dose-dependent manner in all isolates of Phomopsis. The garlic extract had significant inhibition on the growth of all isolates with complete inhibition at 80% concentration. The highest levels of percentage inhibition of mycelial growth were with garlic extract followed by shallot and chili extracts, respectively. The study also showed that these plant extracts contained some polyphenols (apigenin, gallic acid, catechin, quercetin, kaempferol and tannic acid which are well-known compounds possessing antifungal activity. Therefore, it is possible that the antifungal properties of these plant extracts were partly due to these polyphenols or unknown active compounds which could not be analyzed in this study. Collectively, these results suggest that local varieties of both shallot and garlic possess strong antifungal properties. Keywords: Chili, Garlic, Para rubber, Phomopsis, Shallot

Cloning and characterization of HbMT2a, a metallothionein gene from Hevea brasiliensis Muell. Arg differently responds to abiotic stress and heavy metals

Energy Technology Data Exchange (ETDEWEB)

Li, Yan; Chen, Yue Yi; Yang, Shu Guang; Tian, Wei Min, E-mail: wmtian9110@126.com

2015-05-22

Metallothioneins (MTs) are of low molecular mass, cysteine-rich proteins. They play an important role in the detoxification of heavy metals and homeostasis of intracellular metal ions, and protecting against intracellular oxidative damages. In this study a full-length cDNA of type 2 plant metallothioneins, HbMT2a, was isolated from 25 mM Polyethyleneglycol (PEG) stressed leaves of Hevea brasiliensis by RACE. The HbMT2a was 372 bp in length and had a 237 bp open reading frame (ORF) encoding for a protein of 78 amino acid residues with molecular mass of 7.772 kDa. The expression of HbMT2a in the detached leaves of rubber tree clone RY7-33-97 was up-regulated by Me-JA, ABA, PEG, H{sub 2}O{sub 2}, Cu{sup 2+} and Zn{sup 2+}, but down-regulated by water. The role of HbMT2a protein in protecting against metal toxicity was demonstrated in vitro. PET-28a-HbMT2-beared Escherichia coli. Differential expression of HbMT2a upon treatment with 10 °C was observed in the detached leaves of rubber tree clone 93-114 which is cold-resistant and Reken501 which is cold-sensitive. The expression patterns of HbMT2a in the two rubber tree clones may be ascribed to a change in the level of endogenous H{sub 2}O{sub 2}. - Highlights: • Cloning an HbMT2a gene from rubber tree. • Analyzing expression patterns of HbMT2a upon abiotic stress and heavy metal stress. • Finding different expression patterns of HbMT2a among two Hevea germplasm. • The expressed protein of HbMT2a enhances copper and zinc tolerance in Escherichia coli.

Analysis of Aqueous Extractable Protein in Radiation Pre vulcanized Natural Rubber Latex (RVNRL) And Sulphur Pre vulcanized Natural Rubber Latex (SVNRL)

International Nuclear Information System (INIS)

Sofian Ibrahim; Mohd Noor Wadi Mat Lazim; Syuhada Ramli; Keong, C.C.; Khairul Hisyam Mohd Yusof; Muhammad Saiful Omar; Najib Mohd Zakey; Hafizuddin Maseri; Noor Hasni Mohd Ali

2015-01-01

The use of radiation do not only produces Radiation Pre vulcanized Natural Rubber Latex (RVNRL) that can be used for the production of nitrosamines free products, moreover, RVNRL also able to exclude type IV allergy that caused by high protein content in the products. Leaching water from production of finger coat from RVNRL and Sulphur Pre vulcanized Natural rubber Latex (SVNRL) has been collected. Extractable protein content from water samples measured according to the test protocol ASTM D5712-2010. Water from leaching process of finger coat made from RVNRL showed a higher protein content than SVNRL. This explains why RVNRL based products contain very low protein content and thus reduce the risk of Type IV allergy. (author)

Study on grafting of different types of acrylic monomers onto natural rubber by γ-rays

International Nuclear Information System (INIS)

Dafader, N.C.; Haque, M.E.; Akhtar, F.; Ahmad, M.U.

2006-01-01

A comparative study of various acrylic monomers for grafting onto natural rubber was done. The stability of natural rubber latex (NRL) against coagulum with monomer, mechanical properties of grafted rubbers and percent of grafting were investigated. The NRL with monomers, methylacrylate (MA), ethylacrylate (EA) and n-butylacrylate (n-BA), is unstable but it is stable with methyl methacrylate (MMA), n-butyl methacrylate (BMA) and cyclohexyl methacrylate (CHMA). The mechanical properties and degree of grafting attained a maximum at a total radiation dose of 4 kGy. The values of tensile properties of MMA and CHMA grafted rubbers are almost similar, and higher than those of BMA grafted rubbers. On the other hand, the degree of grafting for CHMA is higher than those of MMA and BMA grafted rubbers. The infrared (IR) spectra of monomer grafted natural rubber were also studied

The influence of temperature and reaction time in the degradation of natural rubber latex

International Nuclear Information System (INIS)

Siti Zaleha Isa; Rosiyah Yahya; Aziz Hassan; Mohd Tahir

2007-01-01

Liquid natural rubber (LNR /LENR) should be considered as a new material instead of a new type of rubber though they have the same configuration as the rubber used. In this work, thermal degradation of natural rubber latex was carried out to obtain LNR/LENR by varying the reaction time at different temperatures. The degraded polymers were characterized structurally using FTIR and NMR spectroscopies and the average molecular weights were determined by membrane-osmometry and viscometry. (author)

Reinforcing Natural Rubber with Cellulose Nanofibrils Extracted from Bleached Eucalyptus Kraft Pulp

Science.gov (United States)

Chunmei Zhang; Tianliang Zhai; Ronald Sabo; Craig Clemons; Yi Dan; Lih-Sheng Turng

2014-01-01

Reinforced natural rubber (NR) nanocomposites were prepared by solution mixing, casting, and evaporation of pre-vulcanized natural rubber latex and an aqueous suspension of cellulose nanofibrils (CNFs) extracted from bleached eucalyptus kraft pulp. Scanning electron microscopy (SEM) images showed that there were no micro-scaled aggregates observed in the nanocomposites...

Involvement of Ethylene in the Latex Metabolism and Tapping Panel Dryness of Hevea brasiliensis

Science.gov (United States)

Putranto, Riza-Arief; Herlinawati, Eva; Rio, Maryannick; Leclercq, Julie; Piyatrakul, Piyanuch; Gohet, Eric; Sanier, Christine; Oktavia, Fetrina; Pirrello, Julien; Kuswanhadi; Montoro, Pascal

2015-01-01

Ethephon, an ethylene releaser, is used to stimulate latex production in Hevea brasiliensis. Ethylene induces many functions in latex cells including the production of reactive oxygen species (ROS). The accumulation of ROS is responsible for the coagulation of rubber particles in latex cells, resulting in the partial or complete stoppage of latex flow. This study set out to assess biochemical and histological changes as well as changes in gene expression in latex and phloem tissues from trees grown under various harvesting systems. The Tapping Panel Dryness (TPD) susceptibility of Hevea clones was found to be related to some biochemical parameters, such as low sucrose and high inorganic phosphorus contents. A high tapping frequency and ethephon stimulation induced early TPD occurrence in a high latex metabolism clone and late occurrence in a low latex metabolism clone. TPD-affected trees had smaller number of laticifer vessels compared to healthy trees, suggesting a modification of cambial activity. The differential transcript abundance was observed for twenty-seven candidate genes related to TPD occurrence in latex and phloem tissues for ROS-scavenging, ethylene biosynthesis and signalling genes. The predicted function for some Ethylene Response Factor genes suggested that these candidate genes should play an important role in regulating susceptibility to TPD. PMID:26247941

Development of SBR-Nano clay Composites with Epoxidized Natural Rubber as Compatibilizer

International Nuclear Information System (INIS)

Rajasekar, R.; Das, Ch.K.; Gert Heinrich, G.; Das, A.

2009-01-01

The significant factor that determines the improvement of properties in rubber by the incorporation of nano clay is its distribution in the rubber matrix. The simple mixing of nonpolar rubber and organically modified nano clay will not contribute for the good dispersion of nano filler in the rubbery matrix. Hence a polar rubber like epoxidized natural rubber (ENR) can be used as a compatibilizer in order to obtain a better dispersion of the nano clay in the matrix polymer. Epoxidized natural rubber and organically modified nano clay composites (EC) were prepared by solution mixing. The nano clay employed in this study is Cloisite 20A. The obtained nano composites were incorporated in styrene butadiene-rubber (SBR) compounds with sulphur as a curing agent. The morphology observed through X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) shows that the nano clay is highly intercalated in ENR, and further incorporation of EC in SBR matrix leads to partial exfoliation of the nano clay. Dynamic mechanical thermal analysis showed an increase in storage modulus and lesser damping characteristics for the compounds containing EC loading in SBR matrix. In addition, these compounds showed improvement in the mechanical properties.

Rubber particle proteins, HbREF and HbSRPP, show different interactions with model membranes.

Science.gov (United States)

Berthelot, Karine; Lecomte, Sophie; Estevez, Yannick; Zhendre, Vanessa; Henry, Sarah; Thévenot, Julie; Dufourc, Erick J; Alves, Isabel D; Peruch, Frédéric

2014-01-01

The biomembrane surrounding rubber particles from the hevea latex is well known for its content of numerous allergen proteins. HbREF (Hevb1) and HbSRPP (Hevb3) are major components, linked on rubber particles, and they have been shown to be involved in rubber synthesis or quality (mass regulation), but their exact function is still to be determined. In this study we highlighted the different modes of interactions of both recombinant proteins with various membrane models (lipid monolayers, liposomes or supported bilayers, and multilamellar vesicles) to mimic the latex particle membrane. We combined various biophysical methods (polarization-modulation-infrared reflection-adsorption spectroscopy (PM-IRRAS)/ellipsometry, attenuated-total reflectance Fourier-transform infrared (ATR-FTIR), solid-state nuclear magnetic resonance (NMR), plasmon waveguide resonance (PWR), fluorescence spectroscopy) to elucidate their interactions. Small rubber particle protein (SRPP) shows less affinity than rubber elongation factor (REF) for the membranes but displays a kind of "covering" effect on the lipid headgroups without disturbing the membrane integrity. Its structure is conserved in the presence of lipids. Contrarily, REF demonstrates higher membrane affinity with changes in its aggregation properties, the amyloid nature of REF, which we previously reported, is not favored in the presence of lipids. REF binds and inserts into membranes. The membrane integrity is highly perturbed, and we suspect that REF is even able to remove lipids from the membrane leading to the formation of mixed micelles. These two homologous proteins show affinity to all membrane models tested but neatly differ in their interacting features. This could imply differential roles on the surface of rubber particles. © 2013.

Analysis of Physical Properties and Mineralogical of Pyrolysis Tires Rubber Ash Compared Natural Sand in Concrete material

Science.gov (United States)

Syamir Senin, Mohamad; Shahidan, Shahiron; Syazani Leman, Alif; Izzati Raihan Ramzi Hannan, Nurul

2016-11-01

Waste tires pose significant health and environmental concerns if not recycled or discarded properly. At the same time, natural sand is becoming scarcer and costlier due to its non-availability. Waste tires as fine aggregate can be an economical and sustainable alternative to the natural sand. Recent years, the interest on recycling waste tires into civil engineering applications by the researchers has increased. In this research, the chemical and physical properties of the tires rubber ash and the natural sand have been analysed. The densities of the rubber ash are lower than the natural sand. Rubber ash had finer particle size compared to the natural sand. Almost all chemical in the natural sand had in rubber ash with the additional sulphur trioxide and zinc oxide in the rubber ash, made the rubber ash better than natural sand. Rubber ash seems to be a suitable material to use in concrete as sand replacement.

Radiation vulcanization of Philippine natural rubber latex

International Nuclear Information System (INIS)

Dela Rosa, A.M.; Abad, L.V.; Sta.Ana-Relleve, L.P.; Tranquilan-Aranilla, C.O.; Pascual, C.L.

1996-01-01

The response of Philippine natural rubber latex to irradiation vulcanization and the stability of the irradiated natural rubber latex (INRL) upon storage and aging were investigated. Commercially available high ammonia (HA) concentrated latices obtained from various rubber plantations in Mindanao island were treated with 5 phr of n-butyl acrylate (nBA), and gamma-irradiated at the PNRI 60 Co irradiation facility at a dose rate of 2.57 kGy/hr. Unirradiated cast latex films gave different green strengths which varied from 2-11 MPa. Cast films from INRL exhibited maximum tensile strengths were obtained from cast films with low Mg and high nitrogen contents. Thermal analysis using thermogravimetry (TG) revealed one major decomposition product at 374 o -377 o C. Its rate of decomposition decreased to a minimum at 15 kGy, then increased as radiation dose was increased. This trend correlated well with the tensile strength measurements. The stability of the INRL upon storage and aging is an essential parameter to the rubbe latex industry. For storage studies, INRL was stored for various periods of time. It was found that the pH and total solids content of the stored INRL did not change significantly after 12 months of storage; the MST values remained at above 1000 seconds, and the viscosity decreased with time. The cast films exhibited a decline in tensile strength, modulus 300% , and crosslinking density upon storage. While there were observed changes in the physical properties of the INRL during the storage period, the data indicate that these properties were within values acceptable to the latex industry. Tests on the aging properties of INRL films were undertaken. It was shown that among the chemical antioxidants presently used by the latex industry, TNPP demonstrated the highest antioxidant property, followed by Antage DAHQ and Vulcanox BKF. Our data indicate that the natural rubber latex produced and processed in the Philippines is suited for radiation vulcanization

Prediction of direct and indirect genetic gains and genotypic correlations in rubber tree progenies

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Cecília Khusala Verardi

2011-09-01

Full Text Available The objective of this work was to estimate the genetic parameters, genotypic and phenotypic correlations, and direct and indirect genetic gains among and within rubber tree (Hevea brasiliensis progenies. The experiment was set up at the Municipality of Jaú, SP, Brazil. A randomized complete block design was used, with 22 treatments (progenies, 6 replicates, and 10 plants per plot at a spacing of 3x3 m. Three‑year‑old progenies were assessed for girth, rubber yield, and bark thickness by direct and indirect gains and genotypic correlations. The number of latex vessel rings showed the best correlations, correlating positively and significantly with girth and bark thickness. Selection gains among progenies were greater than within progeny for all the variables analyzed. Total gains obtained were high, especially for girth increase and rubber yield, which were 93.38 and 105.95%, respectively. Young progeny selection can maximize the expected genetic gains, reducing the rubber tree selection cycle.

NMR relaxation times of natural rubber latex

International Nuclear Information System (INIS)

Harun, S.; Aziz, H.; Basir, Z.

1994-01-01

NMR relaxation times T sub 1 and T sub 2 of natural rubber latex have been measured at 25 degree C on a pulsed NMR spectrometer. The work focuses on the variation of the relaxation times with the amount of water content from 0% to 50%. The water content was adjusted by centrifuging and removing a certain amount of water from the sample. The data were analysed using a biexponential fitting procedure which yields simultaneously either T sub 1a and T sub 1b or T sub 2a and T sub 2b. The amount of solid was compared with the known amount of dry rubber content

Effect of gamma radiation dose and sensitizer on the physical properties of irradiated natural rubber latex

International Nuclear Information System (INIS)

Komgrit, R.; Thawat, C.; B, Tripob; Wirach, T.

2009-07-01

Full text: The vulcanization of natural rubber latex can be induced by gamma radiation, which enhances cross-linking within the rubber matrix. The purpose of this research is to investigate the effect of gamma radiation dose and sensitizers on the physical properties of irradiated natural rubber. Three sensitizers n-butyl acrylate (n-B A), tetrachloroethylene (C 2 Cl 4 ) and trichloromethane (CHCl 3 ) were mixed with natural rubber latex before irradiation with gamma ray dose varied from 14 to 22 kGy. Results showed that the mixture of three sensitizers with specific ratios effectively induced the cross-linking of natural rubber latex. The cross-linking ratio and improved physical properties increased with increasing gamma dose. Therefore, the mixture ratios of n-B A, C 2 Cl 4 and CHCl 3 have shown to be a critical parameter in the vulcanization of natural rubber latex by gamma radiation

Rubber trees demonstrate a clear retranslocation under seasonal drought and cold stresses

Directory of Open Access Journals (Sweden)

Yuwu Li

2016-12-01

Full Text Available Having been introduced to the northern edge of Asian tropics, the rubber tree (Hevea brasiliensis has become deciduous in this climate with seasonal drought and cold stresses. To determine its internal nutrient strategy during leaf senescence and deciduous periods, we investigated mature leaf and senescent leaf nutrients, water-soluble soil nutrients and characteristics of soil microbiota in nine different ages of monoculture rubber plantations. Rubber trees demonstrate complicated retranslocation of N, P and K during foliar turnover. Approximately 50.26% of leaf nutrients and 21.47% of soil nutrients were redistributed to the rubber tree body during the leaf senescence and withering stages. However, no significant changes in the structure- or function-related properties of soil microbes were detected. These nutrient retranslocation strategy may be important stress responses. In the nutrient retranslocation process, soil plays a dual role as nutrient supplier and nutrient bank. Soil received the nutrients from abscissed leaves, and also supplied nutrients to trees in the non-growth stage. Nutrient absorption and accumulation began before the leaves started to wither and fall.

Qualidade fisiológica de sementes de seringueira (Hevea brasiliensis Muell. Arg., tratadas com benlate durante o armazenamento Physiological quality of rubber tree seed treated with benomyl during storage

Directory of Open Access Journals (Sweden)

R.D. Vieira

1995-04-01

Full Text Available A ocorrência de um período relativamente frio e seco, imediatamente após o período de coleta de sementes de seringueira - Hevea brasiliensis Muell. Arg. (março-abril, levou à realização do presente trabalho com o objetivo de encontrar condições adequadas de preservação da qualidade fisiológica das sementes. Assim, estudou-se a qualidade fisiológica de sementes, tratadas com Benlate (0,1%, e armazenadas em sacos de polietileno transparente, por períodos de 0 a 5 meses, sob condições ambientais de laboratório. Para a avaliação da qualidade fisiológica das sementes, determinou-se a germinação e o vigor através do índice de velocidade de emergência (IVE e do comprimento da parte aérea das plântulas (CPA, em 1987 e 1988. A germinação e o IVE foram obtidos sob duas condições ambientais diferentes, ambiente do laboratório e em germinador a 30°C. O tratamento fungicida utilizado não exerceu efeito significativo na preservação das sementes. A germinação, o IVE e o CPA reduziram-se com o prolongamento do armazenamento. Os valores da germinação foram baixo desde o início dos trabalhos, o que pode ser atribuído ao teor de água inicial, que estava abaixo de 30%. O teste de germinação de sementes dessa espécie pode ser feito utilizando-se areia como substrato, a 30°C e com a contagem final aos 20 dias após a instalação do teste.After rubber tree (Hevea brasiliensis Muell. Arg. seeds reach the physiological maturity, there is a relatively dry and cold period in the State of São Paulo, which led to the present work, in order to evaluate environmental conditions that maintain physiological seed quality. The physiological quality of rubber tree seeds, treated with benomyl (0,1% and stored in plastic bags, was studied up to 5 months, during 87/88. The seed bags were kept under laboratory conditions during the whole storage period. To evaluate physiological seed quality, germination and vigor (germination speed

Electron linear accelerator system for natural rubber vulcanization

Science.gov (United States)

Rimjaem, S.; Kongmon, E.; Rhodes, M. W.; Saisut, J.; Thongbai, C.

2017-09-01

Development of an electron accelerator system, beam diagnostic instruments, an irradiation apparatus and electron beam processing methodology for natural rubber vulcanization is underway at the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The project is carried out with the aims to improve the qualities of natural rubber products. The system consists of a DC thermionic electron gun, 5-cell standing-wave radio-frequency (RF) linear accelerator (linac) with side-coupling cavities and an electron beam irradiation apparatus. This system is used to produce electron beams with an adjustable energy between 0.5 and 4 MeV and a pulse current of 10-100 mA at a pulse repetition rate of 20-400 Hz. An average absorbed dose between 160 and 640 Gy is expected to be archived for 4 MeV electron beam when the accelerator is operated at 400 Hz. The research activities focus firstly on assembling of the accelerator system, study on accelerator properties and electron beam dynamic simulations. The resonant frequency of the RF linac in π/2 operating mode is 2996.82 MHz for the operating temperature of 35 °C. The beam dynamic simulations were conducted by using the code ASTRA. Simulation results suggest that electron beams with an average energy of 4.002 MeV can be obtained when the linac accelerating gradient is 41.7 MV/m. The rms transverse beam size and normalized rms transverse emittance at the linac exit are 0.91 mm and 10.48 π mm·mrad, respectively. This information can then be used as the input data for Monte Carlo simulations to estimate the electron beam penetration depth and dose distribution in the natural rubber latex. The study results from this research will be used to define optimal conditions for natural rubber vulcanization with different electron beam energies and doses. This is very useful for development of future practical industrial accelerator units.

A comparative investigation on strain induced crystallization for graphene and carbon nanotubes filled natural rubber composites

Directory of Open Access Journals (Sweden)

D. H. Fu

2015-07-01

Full Text Available Natural rubber containing graphene and carbon nanotubes (CNTs composites were prepared by ultrasonicallyassisted latex mixing. Natural rubber filled by both graphene and CNTs show significant enhanced tensile strength, while graphene exhibits a better reinforcing effect than CNTs. Strain-induced crystallization in natural rubber composites during stretching was determined by synchrotron wide-angle X-ray diffraction. With the addition of CNTs or graphene, the crystallization for natural rubber occurs at a lower strain compared to unfilled natural rubber, and the strain amplification effects were observed. The incorporation of graphene results in a faster strain-induced crystallization rate and a higher crystallinity compared to CNTs. The entanglement-bound rubber tube model was used to analyze the chain network structure and determine the network parameters of composites. The results show that the addition of graphene or CNTs has an influence on the molecular network structure and improves the contribution of entanglement to the conformational constraint, while graphene has a more marked effect than CNTs.

Selection and genetic gains for juvenile traits in progenies of Hevea in São Paulo State, Brazil

Directory of Open Access Journals (Sweden)

Paulo de Souza Gonçalves

2004-01-01

Full Text Available Five yield traits were investigated in three-year-old progenies from open-pollinated rubber trees [Hevea brasiliensis (Willd. ex Adr. de Juss Muell.-Arg.]. Twenty progenies were evaluated in a randomized, complete block design replicated three times using 10 plants per linear plot at the North Central Experimental Station in Pindorama, São Paulo State, Brazil. The characters evaluated included the average yield of rubber, growth vigor, bark thickness, total number of latex vessel rings and latex vessel size. Highly significant (p were 37%, 35%, 69%, 10% and 16%, respectively. Significant positive genotypic and phenotypic correlations were found between the yield of rubber and growth vigor (r g = 0.73, r p = 0.70, bark thickness (r g = 0.70**, r p = 0.75** and the total number of latex vessel rings (r g = 0.64, r p = 0.80. There was no relationship between yield and latex vessel size, growth vigor or total number of latex vessel rings. Based on these data, selecting the best two out of 20 progenies would result in a genetic gain of 12.3% and 6.8% for yield of rubber and growth vigor, respectively. The two best individual ortets within each progeny would result in a genetic gain of 27.7% and 9.1%, with a total gain of 40% and 16% for these two traits, respectively.

Permeation Behavior and Physical Properties of Natural Rubber Nanocomposites

National Research Council Canada - National Science Library

Zukas, Walter; Sennett, Michael; Welsh, Elizabeth; Rodriguez, Axel; Ziegler, David; Touchet, Paul

2004-01-01

.... A study was carried out to examine the effects of varying nanoparticle morphology and composition on the mechanical and barrier properties of polymer nanocomposites made with natural rubber (NR...

Natural rubber/high density polyethylene/ground rubber composites vulcanized by gamma irradiation

International Nuclear Information System (INIS)

Shaltout, N.A.; Abou zeid, M.M.; Khalil, A.M.; El Miligy, A.A.

2010-01-01

Natural rubber (NR) was blended mechanically with 50 phr high density polyethylene (HDPE). the mechanical, physical and thermal properties of NR/HDPE blend and its composites with different contents of ground tire rubber (GTR) before and after exposure to gamma irradiation to various doses up to 250 kGy were studied. Also, the change in structure morphology of irradiated NR/HDPE blend as well as NR/HDPE/GTR composites was examined by scanning electron microscope (SEM). The results showed that the substitution of a part of virgin NR with GTR decreases the mechanical and physical properties but not to the extent of deterioration . However, it was found that the mechanical and physical properties were improved after gamma irradiation . Composite of NR/GTR/HDPE (75/25/50) showed good properties. Scanning electron microscope showed homogeneity between the irradiated composites ingredients.

Identification, Functional Study, and Promoter Analysis of HbMFT1, a Homolog of MFT from Rubber Tree (Hevea brasiliensis

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Zhenghong Bi

2016-03-01

Full Text Available A homolog of MOTHER OF FT AND TFL1 (MFT was isolated from Hevea brasiliensis and its biological function was investigated. Protein multiple sequence alignment and phylogenetic analysis revealed that HbMFT1 conserved critical amino acid residues to distinguish MFT, FLOWERING LOCUS T (FT and TERMINAL FLOWER1 (TFL1-like proteins and showed a closer genetic relationship to the MFT-like group. The accumulation of HbMFT1 was generally detected in various tissues except pericarps, with the highest expression in embryos and relatively higher expression in roots and stems of seedlings, flowering inflorescences, and male and female flowers. HbMFT1 putative promoter analysis showed that tissue-specific, environmental change responsive and hormone-signaling responsive elements were generally present. HbMFT1 was strongly induced under a short-day condition at 28 °C, with the highest expression after the onset of a day. Overexpression of HbMFT1 inhibited seed germination, seedling growth, and flowering in transgenic Arabidopsis. The qRT-PCR further confirmed that APETALA1 (AP1 and FRUITFULL (FUL were drastically down-regulated in 35S::HbMFT1 plants. A histochemical β-glucuronidase (GUS assay showed that HbMFT1::GUS activity was mainly detected in stamens and mature seeds coinciding with its original expression and notably induced in rosette leaves and seedlings of transgenic Arabidopsis by exogenous abscisic acid (ABA due to the presence of ABA cis-elements in HbMFT1 promoter. These results suggested that HbMFT1 was mainly involved in maintenance of seed maturation and stamen development, but negatively controlled germination, growth and development of seedlings and flowering. In addition, the HbMFT1 promoter can be utilized in controlling transgene expression in stamens and seeds of rubber tree or other plant species.

Master curves for the sulphur assisted crosslinking reaction of natural rubber in the presence of nano- and nano-structured sp2 carbon allotropes

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S. Musto

2017-06-01

Full Text Available In this paper, master curves are reported for the crosslinking of a diene rubber with a sulphur based system in the presence of either nano- or nano-structured carbon allotropes, such as carbon nanotubes (CNT, a nanosized graphite with high surface area (HSAG and carbon black (CB. Poly(1,4-cis-isoprene from Hevea Brasiliensis was the diene rubber and crosslinking was performed in temperatures ranging from 151 to 180 °C, with carbon allotropes below and above their percolation threshold. Such carbon allotropes were characterized by different aspect ratio, surface area and pH. However, in the crosslinking reaction, they revealed common behaviour. In fact, the specific interfacial area could be used to correlate crosslinking parameters, such as induction time (ts1 and activation energy (Ea calculated by applying the autocatalytic model. Monotonous decrease of ts1 and increase of Ea were observed, with points lying on master curves, regardless of the nature of the carbon allotropes. Remarkable differences were however observed in the structure of the crosslinking network: when the carbon allotrope was above the percolation threshold much larger crosslinking density was obtained in the presence of CNT whereas composites based on HSAG became soluble in hydrocarbon solvent, after the reaction with a thiol. Proposed explanation of these results is based on the reactivity of carbon allotropes with sulphur and sulphur based compounds, demonstrated through the reaction of 1-dodecanethiol and sulphur with CNT and HSAG and with a model substrate such as anthracene.

Vulcanization Kinetics of Natural Rubber Based On Free Sulfur Determination

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Abu Hasan

2013-05-01

Full Text Available The determination of free sulfur in the rubber vulcanizates provided significant representation of vulcanization reaction. In this research, the effects of vulcanization temperature, the mixing method of carbon black into rubber, the ingredients mixing sequence and the type of carbon black were studied on masticated and milled natural rubber in which the reaction was observed by un-reacted sulfur determination. The results showed that higher vulcanization temperature provided faster vulcanization reaction and greater reaction rate constant. Similarly, the mixing sequence of ingredient and carbon black into rubber influenced the rate of vulcanization reaction. The subsequent ingredients mixing sequence, in this case, resulted in higher vulcanization rate compared to that of the simultaneous one. However, the mixing method of carbon black into rubber brought small effect on the rate of vulcanization reaction. The type of carbon black applied was observed to influence the reaction rate of vulcanization. Smaller particle sizes of carbon black gave larger reaction rate constant. In this case, the type of carbon black N 330 gave faster vulcanization rate than that of N 660.

Modification of (DGEBA epoxy resin with maleated depolymerised natural rubber

Directory of Open Access Journals (Sweden)

2008-04-01

Full Text Available In this work, diglycidyl ether of bisphenol A (DEGBA type epoxy resin has been modified with maleated depolymerised natural rubber (MDPR. MDPR was prepared by grafting maleic anhydride onto depolymerised natural rubber. MDPR has been characterized by Fourier transform infrared (FT-IR spectroscopy and nuclear magnetic resonance spectroscopy. MDPR was blended with epoxy resin at three different ratios (97/3, 98/2 and 99/1, by keeping the epoxy resin component as the major phase and maleated depolymerised natural rubber component as the minor phase. The reaction between the two blend components took place between the acid/anhydride group in the MDPR and the epoxide group of the epoxy resin. The proposed reaction schemes were supported by the FT-IR spectrum of the uncured Epoxy/MDPR blends. The neat epoxy resin and Epoxy/MDPR blends were cured by methylene dianiline (DDM at 100°C for three hours. Thermal, morphological and mechanical properties of the neat epoxy and the blends were investigated. Free volume studies of the cured, neat epoxy and Epoxy/MDPR blends were correlated with the morphological and mechanical properties of the same systems using Positron Annihilation Lifetime Studies.

Gamma irradiator design concepts for radiation vulcanisation of natural rubber latex

International Nuclear Information System (INIS)

Aggarwal, K.S.; Muralidharan, P.; Apte, M.G.; Kalurkar, A.R.; Shah, B.M.

1990-01-01

Radiation vulcanisation of natural rubber latex (NRL) is a new and yet unproven technology and one which involves undefined problems of consumer acceptance and high degree of radiation risk. Therefore, the designer should take care that the initial capital cost of the plant is as low as possible to keep the unit processing cost low during the initial lean period of the product requirement by the market. Three irradiators to process natural rubber latex have been designed as per capacity requirement of the user. Their salient features are described. (author). 2 tabs., 24 figs

Molecular Diffusion of Toluene through CaCO3-Filled Natural Rubber Composites

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Hedayatollah Sadeghi Ghari

2012-12-01

Full Text Available The transport properties of liquids and gases through polymeric materialsplay a very important role in some areas of industrial applications. In thisstudy, natural rubber (NR/CaCO3 composites were prepared by melt mixingmethod. By equilibrium swelling test, the transport process of toluene in the prepared natural rubber composites was investigated. The diffusion and transport of toluene through calcium carbonate-filled natural rubber composites have been studied in the temperature range 25–45°C. The diffusion of toluene through these composites was studied with special reference to the effect of filler concentration and temperature.The transport coefficients such as diffusion, permeation and sorption coefficients were estimated from the swelling data. To find out the mechanism of diffusion in prepared composites, the results of swelling studies were applied to an empirical equation. In these composites, diffusion is approximately based on Fickian diffusion mechanism and by increases in temperature; diffusion mechanism is more close to Fickian mechanism. Increase of filler content in composite would result in decreased ultimateswelling and slower diffusion rate of solvent. The diffusion rate, diffusion coefficient and the permeability increased by temperature. The study of the diffusion of toluene through filled natural rubber indicated that the concentration of filler plays an important role in the diffusion, sorption and permeation coefficients. Also interfacial interactions in NR composites were checked by dynamic-mechanical analysis. The microstructure and dispersion of calcium carbonate particles in natural rubber matrix were studiedby field emission scanning electron microscopy (FE-SEM. In general, the results of swelling tests, dynamic-mechanical analysis and FE-SEM images show that the optimized value of filler in NR composites is equal to 10 phr calcium carbonate.

Effect of gamma irradiation on the properties of natural rubber/styrene butadiene rubber blends

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A.B. Moustafa

2016-09-01

Full Text Available Blends of natural rubber (NR with styrene butadiene rubber (SBR with varying ratios have been prepared. Vulcanization of the prepared blends has been induced by irradiation of gamma rays with varying doses up to 250 kGy. Mechanical properties, namely tensile strength, tensile modulus at 100% elongation, elongation at break have been followed up as a function of irradiation dose as well as blend composition. Physical properties, namely gel fraction and swelling number have been followed up using benzene as a solvent. Thermal measurements namely thermogravimetric analysis were carried out. The results indicated that the addition of NR has improved the properties of NR / SBR blends. Also NR/SBR blend is thermally stable than NR alone.

Natural membranes of Hevea brasiliensis latex as delivery system for Casearia sylvestris leaf components

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Flávio A. Carvalho

Full Text Available ABSTRACT Natural latex from Hevea brasiliensis (Wild. ex A.Juss Müll.Arg., Euphorbiaceae, showed angiogenic action and Casearia sylvestris Sw., Salicaceae, leaf derivatives presented anti-inflammatory and wound healing activities. Therefore, an association of these effects was interesting for wound healing applications. The aims of this study were the development of membranes of natural latex incorporated with C. sylvestris leaf derivatives (ethanolic extract, diterpene concentrated fraction and casearin J, their chemical and physical characterization, and the evaluation of in vitro skin permeation and retention of C. sylvestris bioactive secondary metabolites (diterpenes and phenolic compounds. The membranes were developed mixing hydroethanolic solutions of C. sylvestris derivatives with latex and drying them in a desiccator. They were characterized by infrared spectroscopy, scanning electron microscopy, water vapor permeability and mechanical resistance assays, demonstrating that all membranes were permeable, resistant and homogeneous in surfaces. The permeation and retention assays demonstrated dermal penetration of phenolic compounds for ethanolic extract membrane and of casearin-like clerodane diterpenes for all membranes, indicating that these membranes have great potential for therapeutical application as a topical system for C. sylvestris components releasing.

Shape memory alloy wire-based smart natural rubber bearing

International Nuclear Information System (INIS)

Hedayati Dezfuli, F; Shahria Alam, M

2013-01-01

In this study, two types of smart elastomeric bearings are presented using shape memory alloy (SMA) wires. Due to the unique characteristics of SMAs, such as the superelastic effect and the recentering capability, the residual deformation in SMA-based natural rubber bearings (SMA-NRBs) is significantly reduced whereas the energy dissipation capacity is increased. Two different configurations of SMA wires incorporated in elastomeric bearings are considered. The effect of several parameters, including the shear strain amplitude, the type of SMA, the aspect ratio of the base isolator, the thickness of SMA wire, and the amount of pre-strain in the wires on the performance of SMA-NRBs is investigated. Rubber bearings are composed of natural rubber layers bonded to steel shims as reinforcement. Results show that ferrous SMA wire, FeNiCuAlTaB, with 13.5% superelastic strain and a very low austenite finish temperature (−62 °C), is the best candidate to be used in SMA-NRBs subjected to high shear strain amplitudes. In terms of the lateral flexibility and wire strain level, the smart rubber bearing with a cross configuration of SMA wires is more efficient. Moreover, the cross configuration can be implemented in high-aspect-ratio elastomeric bearings since the strain induced in the wire does not exceed the superelastic range. When cross SMA wires with 2% pre-strain are used in a smart NRB, the dissipated energy is increased by 74% and the residual deformation is decreased by 15%. (paper)

Development of natural rubber membranes for separation of methyl tert-butyl ether and methanol

International Nuclear Information System (INIS)

Nur Azrini Ramlee; Ghazali Mohd Nawawi; Khairul Zaman Dahlan

2010-01-01

As a new commercial process, membrane separation raises significant expectations in the process plant of the future and therefore this research was being initiated to develop and characterize pervaporation membrane based on natural rubber (NR). Natural Rubber SMR-L grade which was supplied by Malaysia Rubber Research Institute (MRRI) was used for the development of the membranes via interpenetrating polymer network (IPN) techniques. Polystyrene (PS) was used to modify the natural rubber to further improve their mechanical and chemical properties. The membranes were prepared with various blend ratios of natural rubber, polystyrene and divinyl benzene as cross linker with constant 1 % of dicumyl peroxide as the initiator. The developed membranes were then characterized to study the functional group presence, membranes morphology, crosslink density, tear strength, adsorption of the membranes and pervaporation separation of Methyl-Tert-Butyl-Ether (MTBE) and Methanol. Pervaporation process was conducted by using varies of MTBE concentration 10, 30, 50 and 70 wt % and at differ operation temperature, 25 degree Celsius and 55 degree Celsius. Separation performance of IPN NR/ PS membranes were based on the presented permeation flux and separation factor. Examination through Fourier Transform Infrared Spectroscopy (FTIR), determined crosslink density and tear strength, 6 series of IPN NR/ PS membranes were successfully developed using natural rubber. Observation from Scanning Electron Microscopy (SEM) showed that the membranes were dense and appropriated for the pervaporation process application. From the pervaporation of MTBE and Methanol, IPN NR/ PS membranes of series D4N30 shown low permeation flux of MTBE but high separation factor while D2N70 membranes was vice versa for both temperature of 25 degree Celsius and 55 degree Celsius. (author)

Extractable proteins from field radiation vulcanized natural rubber latex

Energy Technology Data Exchange (ETDEWEB)

Parra, Duclerc F. [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil)]. E-mail: dfparra@ipen.br; Pinto Martins, Carlos Felipe [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil); Collantes, Hugo D.C. [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil); Lugao, Ademar B. [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil)

2005-07-01

The type I allergy associated with the use of natural rubber latex (NRL) products is caused by the NRL proteins leached by the sweat or other body fluids. Makuuchi's group proposed for the first time the proteins removal by the addition of water-soluble polymers (WSP) on radiation vulcanization of natural rubber latex (RVNRL) that is a promising process under development in many countries. In this study, Brazilian field natural rubber was irradiated with a {sup 60}Co gamma source to reduce the content of WSP in the final product. WSP was used as additive to improve the extraction of protein. After irradiation the RVNRL was centrifuged to extract the WSP and proteins. The analytical methodology for protein content was based on the modified Lowry method according to ASTM D5712. Protein determination was carried out in serum of latex and in the extracts of the gloves. The concentration of extractable water-soluble proteins in serum of irradiated field NRL (NRL1), not irradiated one (NRL2); of twice centrifuged sample with polymer additive NRL (NRL3) and of the glove manufactured (NRLG) are compared with commercial glove (CG). The irradiation process increases the extractable water-soluble proteins, EP, as reported in the literature. In this study the use of polymeric additive on the bi-centrifugation process to remove protein was successful and the EP of the glove obtained in NRL3 was at around 40% of the commercial glove.

De groei van jonge Hevea-oculaties = The growth of young Hevea buddings

NARCIS (Netherlands)

Ostendorf, F.W.

1933-01-01

Results were presented of studies on the initial growth of Hevea buddings, at the Proefstation West-Java, Buitenzorg (now Bogor). The time elapsing between cutting off the stock above the union and sprouting of the implanted bud was a clonal character; so also was the angle between the young sprout

Thermal, Morphological and Physic-Mechanical Properties of Natural Rubber - CaCO3 Composites Using Jatropha Oil as Softener.

Directory of Open Access Journals (Sweden)

Nasruddin

2018-01-01

Full Text Available The urgency of green technology in rubber compounding has become a critical issue recently. In this research, the effect of using renewable resources in rubber compounding has been studied. Commercial Calcium Carbonate, Silica and Jatropha Oil were used in natural rubber composite. The research was designed by varying the types of commercial filler namely CaCO3 (47-51 phr, silica (47-51 phr and Jatropha Oil (4-6 phr in natural rubber composites (SIR-20. The formulas were intentionally designed for rubber tips vulcanizates. The samples were characterized by the determination of physic-mechanical, thermal (TGA and morphological (SEM properties. From the measured results, there is no significant effect on the tensile strength, specific gravity, and hardness on the loading of commercial CaCO3 and Silica in natural rubber composites using Jatropha Oil. However, a slight difference in elongation at break and abrasion resistance could be detected. Compared to the commercial rubber tips, the rubber tips produced in this research have higher tensile strength, elongation at break and abrasion resistance. Due to the usage of commercial CaCO3 and Silica, the SEM micrographs show rough surface because of the agglomeration. The thermogram shows clearly the compositional analysis of the rubber tips vulcanizates consist of Jatropha Oil and natural rubber, CaCO3, ash and other filler residues such as Silica.

Liberação de componentes do extrato de Casearia sylvestris Swartz empregando membranas de látex natural como suporte

OpenAIRE

Alberto Trecco; Felipe Azevedo Borges; Elaise G. Pierri; André Gonzaga dos Santos; Chung Man Chin; Rondinelli Donizetti Herculano

2014-01-01

A membrana de látex natural (NRL – Natural Rubber Latex), manipulada a partir do látex extraído da seringueira Hevea brasiliensis, tem apresentado grande potencial de aplicação no campo da biomedicina e dos biomateriais. Graças a sua biocompatibilidade e baixa taxa de rejeição, ela tem sido utilizada para próteses e enxertos, atuando como estimulante da angiogênese, adesão celular e barreira física a agentes infecciosos. Além dessas aplicações, as membranas são utiliza...

Alternative secondary accelerator for silica-filled natural rubber formulations

NARCIS (Netherlands)

Kaewsakul, Wisut; Sahakaro, Kannika; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

2013-01-01

Dithiophosphate (DTP) displays a good efficiency towards improved overall properties of silica-reinforced natural rubber compounds, when it is used as secondary accelerator in a sulfenamide primary accelerated sulfur vulcanization system. Comparing DTP with diphenylguanidine (DPG), DTP is more

Radiation vulcanization of natural rubber latex

International Nuclear Information System (INIS)

Wan Manshol bin Wan Zin; Norjanah binti Mohid

1994-01-01

This paper describes the experimental techniques and the results of radiation vulcanization of natural rubber latex carried out on several high ammonia latices available in the country. The efficiency of various sensitisers and stabilisers used were evaluated in terms of the gamma radiation dose required to produce the maximum tensile strengths. The extent of crosslinking of RVNRL sample films were estimated by equilibrium swelling ratio measurements. The stability of pre-irradiated and post-irradiated samples were monitored using viscosity measurements as the parameter

Additive free thermoplastic vulcanizates based on natural rubber

Energy Technology Data Exchange (ETDEWEB)

Mondal, Manas, E-mail: mondal@ipfdd.de [Leibniz-Institut für Polymerforschung Dresden e.V., Institut für Polymerwerkstoffe, Hohe Straße 6, 01069 Dresden (Germany); Technische Universität Dresden, Institut für Werkstoffwissenschaft, 01069 Dresden (Germany); Gohs, Uwe, E-mail: gohs@ipfdd.de [Leibniz-Institut für Polymerforschung Dresden e.V., Institut für Polymerwerkstoffe, Hohe Straße 6, 01069 Dresden (Germany); Wagenknecht, Udo [Leibniz-Institut für Polymerforschung Dresden e.V., Institut für Polymerwerkstoffe, Hohe Straße 6, 01069 Dresden (Germany); Heinrich, Gert [Leibniz-Institut für Polymerforschung Dresden e.V., Institut für Polymerwerkstoffe, Hohe Straße 6, 01069 Dresden (Germany); Technische Universität Dresden, Institut für Werkstoffwissenschaft, 01069 Dresden (Germany)

2013-12-16

Electron induced reactive processing (EIReP) is an eco-friendly and sustainable reactive processing method based on the use of high energy electrons. It was used to cross-link the elastomeric domain phase during melt mixing in order to prepare natural rubber (NR) and polypropylene (PP) based thermoplastic vulcanizates (TPVs). The electron treatment with various values of absorbed dose showed a prominent effect on mechanical, rheological, and morphological characteristics of the PP/NR TPVs. SEM and TEM studies confirmed that these TPVs can exists across the co-continuous or discrete phase morphology. The maximum set of mechanical properties (tensile strength of 15 MPa and elongation at break of more than 500%) were obtained at an absorbed dose of 100 kGy for a 50/50 blend ratio of NR and PP without addition of any compatibilizer or chemicals. At higher values of absorbed dose the degradation of polypropylene showed a negative impact on the properties of the TPVs. Depending on the morphology and the evaluation of mechanical properties a structure–property co-relationship is drawn on the basis of common phenomenological understanding of the TPVs. - Highlights: • Dynamic vulcanization of 50:50 PP/NR blend by high energy electron beam. • PP/NR TPVs show rubber like behavior with melt processability. • High tensile strength of 15 MPa and large extensibility beyond 500%. • Complete phase inversed morphology from NR to PP matrix. • Vulcanized natural rubber particle size of 1–3 μm.

ENHANCEMENT OF RESISTANCE TO OXIDATIVE DEGRADATION OF NATURAL RUBBER THROUGH LATEX DEGRADATION

Institute of Scientific and Technical Information of China (English)

无

1998-01-01

A fully characterised natural rubber latex was subjected to mechanical degradation by stirring at intervals. The resistance to oxidative degradation of the different samples were studied by measuring the Plasticity retention indices (PRI).The results show that there is an enhancement of the PRI from 57% for the undegraded rubber to 79% for the one-hour degraded sample. Further degradation resulted in decrease of PRI as time of degradation increased. Therefore, the one-hour degraded sample is a special rubber with high oxidation resistance which is of great importance in engineering.

Radiation response of Philippine natural rubber latex

International Nuclear Information System (INIS)

Dela Rosa, A.M.; Abad, L.V.; Ana-Relleve, L.S.; Tranquilan-Aranilla, C.; Pascual, C.L.

1998-01-01

Our earlier work has shown that the natural rubber latex (NRL) produced and processed in the Philippines is suited for radiation vulcanization. The cast films from NRL with 50% TSC exhibited maximum tensile strengths of 25-32 MPa at 15 kGy, which is the vulcanization dose or Dv. In the manufacture of dipped NRL products, certain specifications such as %TSC, protein content and tensile properties, must be met to ensure an acceptable product. For radiation vulcanization of natural rubber latex (RVNRL) to be accepted as an alternative process, it must also meet the requirements. Thus, this paper presents additional data on the radiation response of local NRL at different total solids contents (TSC), leachable proteins from NRL films as a function of dose, and the thermal activities of irradiated natural rubber latex (INRL). Different formulations of NRL showed varying tolerances to nBA. Data showed that as %TSC increases, the maximum concentration of nBA that can be added without affecting the stability of the latex decreases. The Dv increases as the %TSC increases and the nBA content decreases. This difference in response may be attributed to a lower concentration of nBA in formulations with higher %TSC. These data indicate that the parameters in the radiation treatment will be dictated by the intended applications of INRL. The thermogravimetric data showed greater stability of INRL to thermal oxidation relative to the unirradiated NRL, which correlates directly with the tensile properties of the INRL. A radiation dose of 10 kGy increased the amount of proteins leached from cast latex films. The amount of extractable proteins did not increase significantly at higher doses. The SDS PAGE analysis of the extractable proteins from unirradiated latex film showed distinct bands. An additional band at 60 Kda appeared at 10 kGy. All these bands became diffuse at higher doses, indicating the radiolysis of the proteins

Mechanical property test of natural rubber bearing for the evaluation of uncertainty value of seismic isolation devices

International Nuclear Information System (INIS)

Kim, Min Kyu; Kim, Jung Han; Choi, In Kil

2012-01-01

Seismic safety of NPP is one of the most important issues in a nuclear field after great east Japan earthquake in 2011. For the improvement of seismic safety of nuclear power plant, seismic isolation is the easiest solution for increasing the seismic safety. Otherwise, the application of seismic isolation devices for nuclear power plants doesn't make the seismic risk of NPP increases always. The rubber bearing have many uncertainties of material properties and large displacement should absorb according to the application of isolation devices. In this study, for the evaluation of uncertainty of the material properties of rubber bearing, material tests for rubber and mechanical properties test for natural rubber bearing were performed. For the evaluation of effect of hardness of rubber, 4 kinds of rubber hardness for material property tests and 2 kinds of rubber hardness for mechanical property test were considered. As a result, the variation of material properties is higher than that of mechanical properties of natural rubber bearings

Irradiation grafting of natural rubber latex with maleic anhydride and its compatibilization of poly(lactic acid)/natural rubber blends

Science.gov (United States)

Pongsathit, Siriwan; Pattamaprom, Cattaleeya

2018-03-01

Maleic anhydride (MA) is an interesting monomer to be grafted onto natural rubber(NR) due to its potential as a compatibilizer of hydrophobic rubbers and polymers with higher polarity. So far, radiation grafting of MA onto NR in latex state has not been reported. In this study, the grafting of NR with MA in latex state was investigated by exposing the latex to cobalt-60 gamma irradiation at a fixed MA content of 9% and a varied absorbed doses from 2 to 10 kGy. The FTIR spectrometer, 1H NMR spectrometer and gel content analysis have confirmed successful grafting of MA onto NR after irradiation. The grafted NRs were then used to increase the compatibility and the impact property of PLA/NR blends. It was found that the highest impact strength of the blends was achieved when the grafting was carried out at the absorbed dose of 4 kGy.

Hydrogenation of liquid natural rubber via diimide reduction in hydrazine hydrate/hydrogen peroxide system

International Nuclear Information System (INIS)

Yusof, Muhammad Jefri Mohd; Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

2015-01-01

Liquid natural rubber (LNR) with molecular weight of lower than 10 5 and shorter polymeric chain than natural rubber was prepared. LNR was then hydrogenated via diimide reduction by oxidation of hydrazine hydrate with hydrogen peroxide. The unsaturated units of the rubber were converted into saturated hydrocarbon to strengthen the backbone of the polymer so it was able to resist thermal degradation. The results indicated that hydrogenation degree of the product (HLNR) could be extended to 91.2% conversion under appropriate conditions. The hydrogenated LNR (HLNR) was characterized using Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The physical characteristics of HLNR were analyzed with Termogravimetric Analysis (TGA)

Hydrogenation of liquid natural rubber via diimide reduction in hydrazine hydrate/hydrogen peroxide system

Science.gov (United States)

Yusof, Muhammad Jefri Mohd; Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

2015-09-01

Liquid natural rubber (LNR) with molecular weight of lower than 105 and shorter polymeric chain than natural rubber was prepared. LNR was then hydrogenated via diimide reduction by oxidation of hydrazine hydrate with hydrogen peroxide. The unsaturated units of the rubber were converted into saturated hydrocarbon to strengthen the backbone of the polymer so it was able to resist thermal degradation. The results indicated that hydrogenation degree of the product (HLNR) could be extended to 91.2% conversion under appropriate conditions. The hydrogenated LNR (HLNR) was characterized using Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The physical characteristics of HLNR were analyzed with Termogravimetric Analysis (TGA).

Hydrogenation of liquid natural rubber via diimide reduction in hydrazine hydrate/hydrogen peroxide system

Energy Technology Data Exchange (ETDEWEB)

Yusof, Muhammad Jefri Mohd; Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

2015-09-25

Liquid natural rubber (LNR) with molecular weight of lower than 10{sup 5} and shorter polymeric chain than natural rubber was prepared. LNR was then hydrogenated via diimide reduction by oxidation of hydrazine hydrate with hydrogen peroxide. The unsaturated units of the rubber were converted into saturated hydrocarbon to strengthen the backbone of the polymer so it was able to resist thermal degradation. The results indicated that hydrogenation degree of the product (HLNR) could be extended to 91.2% conversion under appropriate conditions. The hydrogenated LNR (HLNR) was characterized using Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The physical characteristics of HLNR were analyzed with Termogravimetric Analysis (TGA)

Nanocomposites of natural rubber and polyaniline-modified cellulose nanofibrils

Science.gov (United States)

Cellulose nanofibrils (CNF) were isolated from cotton microfibrils (CM) by acid hydrolysis and coated with polyaniline (PANI) by in situ polymerization of aniline onto CNF in the presence of hydrochloride acid and ammonium peroxydisulfate to produce CNF/PANI. Nanocomposites of natural rubber (NR) re...

Radiation degradation of methyl methacrylate grafted natural rubber

International Nuclear Information System (INIS)

Perera, M.C.S.

1998-01-01

M G rubber is a mixture consisting of the graft copolymer and two home polymers. Natural rubber is known to undergo crosslinking during exposure to high energy radiation where as poly methyl methacrylate is a polymer where high energy radiation causes chain scission. It is interesting to determine how this partially miscible blend of scission and crosslinking polymers will behave under high energy radiation. Dynamic Mechanical Analysis (DMA) was used to study the variations in the glass transition regions during high energy treatment of the polymers. Another techniques that is available to obtain motional information and miscibility of blends is Nuclear Magnetic Resonance Spectroscopy (NMR).The present study is aimed at understanding the changes in the molecular structure of rubber when exposed to high energy radiation. The changes in the dynamic mechanical properties in the glass transition region and solid state NMR were made used of for this investigation. The data obtained from the DMA results were analysed to calculate the radiation chemical yields. The local dynamics were investigated with measurement of carbon relaxation times and molecular structure was studied with focus on the level of intermolecular mixing by proton relaxation times

Thermal-kinetic study of natural rubber latex films vulcanized by using gamma radiation; Estudo termo-cinetico de filmes de latex de borracha natural de Hevea brasiliensis vulcanizada por radiacao gama

Energy Technology Data Exchange (ETDEWEB)

Leal, Ana Paula Pinho Rodrigues; Barros, Glaucione Gomes de [Brasilia Univ., DF (Brazil). Inst. de Quimica; Guedes, Selma M.L. [Instituto de Pesquisa em Energia Nuclear, Sao Paulo, SP (Brazil)

1999-07-01

Vulcanization of natural rubber latex by ionization radiation produces the crosslink in disperse latex particles. Advantages over conventional process of vulcanization are: the absence of carcinogenic nitrosamines, low cytotoxicity and better degradation at room conditions, due to mainly to the absence of sulfur, zinc oxide and dithiocarbamates. Thermogravimetric analysis (TG) is the measurement of the weight change of a material as a function of temperature and time. TG data different heat speed provide an alternative model of the kinetics of degradation of polymeric materials. The kinetic studies of this material showed a single degradation process at least for 76,5% of mass loss. The activation energy was 49 Kcal/mol. For higher mass loss (85%) the degradation was characterized by associate mechanism. (author)

Tear energy and strain-induced crystallization of natural rubber/styrene-butadiene rubber blend

International Nuclear Information System (INIS)

Noguchi, F; Akabori, K; Yamamoto, Y; Kawahara, S; Kawazura, T

2009-01-01

Strain-induced crystallization of natural rubber (NR), dispersed in styrene-butadiene rubber (SBR), was investigated in relation to dimensional feature of a dispersoid and crosslink density of NR by measuring tear energy (G) of crosslinked NR/SBR blends. The crosslinked NR/SBR blends in ratios of 1/9 and 3/7 by weight were prepared by mixing masticated NR and SBR with an internal mixer at a rotor speed of 30 rpm, followed by crosslinking with dicumyl peroxide on a hot press at 444 K for 60 min. The G, measured in wide-ranges of temperature and tear rate, was superposed into a master curve with a Williams-Landel-Ferry shift factor. The G of the NR/SBR(3/7) blend abruptly decreased to a level comparable to that of SBR at about melting temperature of NR crystals formed on straining. The temperature, at which the dramatic decrease in the G occurred, was associated with the dimensional feature of the NR dispersoid and the crosslink density.

Genetic parameters and estimated genetic gains in young rubber tree progenies

Directory of Open Access Journals (Sweden)

Cecília Khusala Verardi

2013-04-01

Full Text Available The objective of this work was to assess the genetic parameters and to estimate genetic gains in young rubber tree progenies. The experiments were carried out during three years, in a randomized block design, with six replicates and ten plants per plot, in three representative Hevea crop regions of the state of São Paulo, Brazil. Twenty-two progenies were evaluated, from three to five years old, for rubber yield and annual girth growth. Genetic gain was estimated with the multi-effect index (MEI. Selection by progenies means provided greater estimated genetic gain than selection based on individuals, since heritability values of progeny means were greater than the ones of individual heritability, for both evaluated variables, in all the assessment years. The selection of the three best progenies for rubber yield provided a selection gain of 1.28 g per plant. The genetic gains estimated with MEI using data from early assessments (from 3 to 5-year-old were generally high for annual girth growth and rubber yield. The high genetic gains for annual girth growth in the first year of assessment indicate that progenies can be selected at the beginning of the breeding program. Population effective size was consistent with the three progenies selected, showing that they were not related and that the population genetic variability is ensured. Early selection with the genetic gains estimated by MEI can be made on rubber tree progenies.

Assessment of six tapping systems for four Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg.,clones in the Colombian High Plains

International Nuclear Information System (INIS)

Quesada Mendez, Isaac; Aristizabal Gutierrez, Fabio Ancizar; Chaves Cordoba, Bernardo

2009-01-01

The rubber yield of four Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg. clones was evaluated on the Colombian high plains in the Meta department: IAN 873 and RRIM 600 (third year of tapping being done) and PB 260 and GT 1 (first year of tapping). Six tapping systems were used, including a combination of different tapping frequencies (d/4 and d/5), Ethephon concentrations (0%, 2.5%, 3.3% and 5%) and a number of applications per year (4 to 8) were also used depending on the clone. The production figures for one commercial year were obtained from assays, using a completely random- block design (having four repetitions) independently defined for each clone: having on average 4446 g rubber/tree of produce per year for the RRIM 600 clone within a system 1/2S, d/4, 6d/7, 10m/12, ET 2.5%, Pa 7/y; 2696 g rubber/tree for the PB 260 clone with 1/2S, d/4, 6d/7, 10m/12, ET 2.5%, Pa 5/y; 3822 g rubber/tree for the IAN 873 clone, 1/2S, d/4, 6d/7, 10m/12, ET 3.3%, Pa 8/y, and 3472 g rubber/ tree for the GT 1 clone, 1/2S, d/4, 6d/7, 10m/12, ET 2.5%, Pa 5/y. The highest produce was obtained with a four-day tapping frequency.

Temperature dependence of the elastocaloric effect in natural rubber

Energy Technology Data Exchange (ETDEWEB)

Xie, Zhongjian, E-mail: zhongjian.xie521@gmail.com; Sebald, Gael; Guyomar, Daniel

2017-07-12

The temperature dependence of the elastocaloric (eC) effect in natural rubber (NR) has been studied. This material exhibits a large eC effect over a broad temperature range from 0 °C to 49 °C. The maximum adiabatic temperature change (ΔT) occurred at 10 °C and the behavior could be predicted by the temperature dependence of the strain-induced crystallization (SIC) and the temperature-induced crystallization (TIC). The eC performance of NR was then compared with that of shape memory alloys (SMAs). This study contributes to the SIC research of NR and also broadens the application of elastomers. - Highlights: • A large elastocaloric effect over a broad temperature range was found in natural rubber (NR). • The caloric performance of NR was compared with that of shape memory alloys. • The temperature dependence of the elastocaloric effect in NR can be prediced by the theory of strain-induced crystallization.

Application of gamma irradiation for incorporation of rubber powder in the formulations of EPDM and natural rubber; Aplicacao da radiacao gama para incorporacao do po de borracha em formulacoes de borracha natural e EPDM

Energy Technology Data Exchange (ETDEWEB)

Kiyan, Ludmila Y.P.; Parra, Duclerc Fernandes; Lugao, Ademar Benevolo, E-mail: ludmilapozzo@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP/CQMA), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente

2013-07-01

The objective of this work was to study the behavior of the recycling of rubber burrs in form of powder, of the rubber industry from EPDM rubber powder and natural rubber with SBR. The rubber powder was irradiated and reused in rubber artifacts formulations for classical vulcanization. The processed material was irradiated using a {sup 60}Co source in doses of 50, 100, 150 and 200 kGy and a dose rate of 5 kGy s-1 at room temperature. The radiation created devulcanization active sites for subsequent integration of the material (rubber powder) in formulations of commercial use. The processes were compared and their products characterized by analytical methods of the physical properties such as strength and elongation. Satisfactory results were found, noting a major spin-off of EPDM chain demonstrated by increased elongation.

Wood Sawdust/Natural Rubber Ecocomposites Cross-Linked by Electron Beam Irradiation

Directory of Open Access Journals (Sweden)

Elena Manaila

2016-06-01

Full Text Available The obtaining and characterization of some polymeric eco-composites based on wood sawdust and natural rubber is presented. The natural rubber was cross-linked using the electron beam irradiation. The irradiation doses were of 75, 150, 300 and 600 kGy and the concentrations of wood sawdust were of 10 and 20 phr, respectively. As a result of wood sawdust adding, the physical and mechanical properties such as hardness, modulus at 100% elongation and tensile strength, showed significant improvements. The presence of wood sawdust fibers has a reinforcing effect on natural rubber, similar or better than of mineral fillers. An increase in the irradiation dose leads to the increasing of cross-link density, which is reflected in the improvement of hardness, modulus at 100% elongation and tensile strength of blends. The cross-linking rates, appreciated using the Flory-Rehner equation, have increased with the amount of wood sawdust in blends and with the irradiation dose. Even if the gel fraction values have varied irregularly with the amount of wood sawdust and irradiation dose it was over 90% for all blends, except for the samples without wood sawdust irradiated with 75 kGy. The water uptake increased with increasing of fiber content and decreased with the irradiation dose.

Structural and Magnetic Properties of Type-M Barium Ferrite - Thermoplastic Natural Rubber Nano composites

International Nuclear Information System (INIS)

Nurhidayaty Mokhtar

2012-01-01

Structural and magnetic properties of type-M barium ferrite (BaFe 12 O 19 ) nanoparticles (∼ 20 nm) embedded in non-magnetic thermoplastic natural rubber (TPNR) matrices were investigated. The TPNR matrices were prepared from high density polyethylene (HDPE) and natural rubber (NR) in the weight ratios of 80:20 and 60:40, respectively, with 10 wt % of NR in the form of liquid natural rubber (LNR) which act as a comparabilities. BaFe 12 O 19 - filled nano composites with 2 - 12 wt % BaFe 12 O 19 ferrite were prepared using a melt- blending technique. Magnetic hysteresis was measured using a vibrating sample magnetometer (VSM) in a maximum field of 10 kOe at room temperature (25 degree Celsius). The saturation magnetisation (MS), remanence (MR) and coercivity (Hc) were derived from the hysteresis loops. The results show that the structural and magnetic properties of nano composites depend on both the ferrite content and the composition of the natural rubber or plastic in the nano composites. All the nano composites exhibit an exchange bias-like phenomenon resulting from the exchange coupling of spins at the interface between the core ferrimagnetic region and the disordered surface region of the nanoparticles. (author)

Structural and physico-mechanical properties of natural rubber/GTR composites devulcanized by microwaves: influence of GTR source and irradiation time

OpenAIRE

Colom Fajula, Xavier; Marin-Genesca, Marc; Mujal Rosas, Ramón María; Formela, Krzysztof; Cañavate Ávila, Francisco Javier

2018-01-01

Ground tire rubber from car and truck was modified using microwave irradiation at variable time. The irradiated ground tire rubber was used as filler in composites based on natural rubber. The composites, with high content of ground tire rubber, were prepared using an internal batch mixer and subsequently cross-linked at 160¿. The influence of the ground tire rubber source (car/truck) and irradiation time on structure, physico-mechanical behaviour, thermal properties and morphology of natural...

Application of radiation vulcanized natural rubber latex in Indonesia

International Nuclear Information System (INIS)

Soebianto, Y.S.; Wiwik Sofiarti; Razzak, M.T.

1996-01-01

The center has carried out R and D of Radiation Vulcanization Natural Rubber Latex (RVNRL) technology and introduced it to the industries since the inauguration and operation of the latex pilot plant in 1983. After years of experiences and the environmental consideration, n-butylacrylate (n-BA) has replaced CCI, as the sensitizer. Until now the introduction program shows that radiation vulcanized latex is more suitable for home industries than large industries. The obstacle of the program is the marketing of the dipped products. In spite of these problems, the introduction of this technology to the people in some undeveloped area of Java has supported the national program to improve their living standard. The problems of nitrosamine and protein allergic have turn up RVNRL to be the substitute of sulfur vulcanized latex in the future. The cooperation with a national condom manufacturer (PT Mitra Banjaran) has applied RVNRL for condom production in the large scale. Soft condoms with less probability of pinhole are obtained, but the technical problem is stickiness after pilling. Supply to a baby teat and a rubber thread manufacturer offers great advantages by not using any chemicals. In spite of the advantages, the problem of latex viscosity for dipping and the low modulus of elasticity of the threads arise. Through those input CAIR-BATAN is conducting the research and development in improving the crosslinking among the rubber particles that are supposed to be the reason of the stickiness and low modulus of elasticity. This effort is expected to be able to broaden the application of RVNRL, and it will be achieved only by the involvement of rubber chemist, rubber technologist, and radiation chemist

Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

Energy Technology Data Exchange (ETDEWEB)

Karim, Ahmad Fikri Abdul, E-mail: a.fikri-89@yahoo.com; Ariff, Zulkifli Mohamad [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Ismail, Hanafi [Cluster for Polymer Composites (CPC), Science and Engineering Research Centre, Engineering Campus, Universiti Sains Malaysia,14300 Nibong Tebal, Pulau Pinang (Malaysia)

2015-07-22

This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM)

Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

International Nuclear Information System (INIS)

Karim, Ahmad Fikri Abdul; Ariff, Zulkifli Mohamad; Ismail, Hanafi

2015-01-01

This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM)

Assembly and Analysis of Differential Transcriptome Responses of Hevea brasiliensis on Interaction with Microcyclus ulei.

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Uriel Alonso Hurtado Páez

Full Text Available Natural rubber (Hevea brasiliensis is a tropical tree used commercially for the production of latex, from which 40,000 products are generated. The fungus Microcyclus ulei infects this tree, causing South American leaf blight (SALB disease. This disease causes developmental delays and significant crop losses, thereby decreasing the production of latex. Currently several groups are working on obtaining clones of rubber tree with durable resistance to SALB through the use of extensive molecular biology techniques. In this study, we used a secondary clone that was resistant to M. ulei isolate GCL012. This clone, FX 3864 was obtained by crossing between clones PB 86 and B 38 (H. brasiliensis x H. brasiliensis. RNA-Seq high-throughput sequencing technology was used to analyze the differential expression of the FX 3864 clone transcriptome at 0 and 48 h post infection (hpi with the M. ulei isolate GCL012. A total of 158,134,220 reads were assembled using the de novo assembly strategy to generate 90,775 contigs with an N50 of 1672. Using a reference-based assembly, 76,278 contigs were generated with an N50 of 1324. We identified 86 differentially expressed genes associated with the defense response of FX 3864 to GCL012. Seven putative genes members of the AP2/ERF ethylene (ET-dependent superfamily were found to be down-regulated. An increase in salicylic acid (SA was associated with the up-regulation of three genes involved in cell wall synthesis and remodeling, as well as in the down-regulation of the putative gene CPR5. The defense response of FX 3864 against the GCL012 isolate was associated with the antagonistic SA, ET and jasmonic acid (JA pathways. These responses are characteristic of plant resistance to biotrophic pathogens.

Pilot Scale Production of Irradiated Natural Rubber Latex and its Dipping Products

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M. Utama

2005-07-01

Full Text Available One hundred and fifty kg natural rubber latex (NRL before and after concentration were added with 3 phr (part hundred ratio of rubber normal butyl acrylate, then the mixture were irradiated at 25 kGy by gamma rays of 60Co in pilot scale. The irradiated natural rubber latex (INRL were then being to use for producing rubber products such as condom, surgical gloves, and spygmomanometer in factory scale. The quality of INRL and rubber products such as : total solid content (TSC, dry rubber content (DRC, KOH, VFA and MST number, tensile strength, modulus, elongation at break, extractable protein content, and response against Type I allergy etc. were evaluated. The economic aspect for producing INRL by means of Gamma Irradiator (GI and Electron Beam Machine (EBM such as payback period (PP, net present value (NPV and internal rate return (IRR were calculated. The results showed that the latex properties of INRL such as DRC, TSC, KOH, VFA, and MST number are not only found to the requirement of the ISO 2004 standard but also the latex has low protein, lipid, and carbohydrate content. The physical and mechanical properties (tensile strength, modulus, and elongation at break of rubber dipping products such as condom, gloves, and sphygmomanometer are not only found to the requirement of ISO 4074, ISO 10282, and ANSI/AAMI SP-1994 standards, but also the allergic response tested clinical latex-sensitive protein allergen by ELISA test on gloves, and by SPT test on condom are found to be negative. It indicates that production of INRL or PVNRL or RVNRL by EBM 250 keV/10 mA, was more cheap than by using gamma γ irradiator 200 kCi, or sulfur vulcanization. The value of PBP (payback period was 2,1 years, NPV (net present value was 4,250 US $, PI (profitability index 1,06 and IRR (internal rate of returns was 25,0%.

Blends of natural rubber and polyurethane lattices studied by solid-state NMR

International Nuclear Information System (INIS)

Ricardo, Nagila M.P.S.; Franca, Francisco C.F. de; Price, Colin; Heatley, Frank

2001-01-01

Molecular mixing in films formed from a mixture of a polyurethane and natural rubber lattices has been studied using 1 H and 13 C solid-state NMR. The techniques employed include 1 H relaxation measurements, and 13 C cross-polarisation and direct excitation methods. The spectra of the blends were essentially a weighted superposition of the spectra of the individual components, indicating that the polyurethane and rubber remained phase-separated in large domains. (author)

SYSTEMES DE RECOLTE DU LATEX ADAPTES A LA SAIGNEE ...

African Journals Online (AJOL)

AISA

des arbres. Il s'agira de définir l'influence de ..... CIRAD-Cultures pérennes, éd.,. Montpellier, France .... Indian. Journal of Natural Rubber Research,. 15(1) : 66 - 71. Obouayeba S. 2005.Contribution à la ... Academy Hevea Malaysia, Malaysian.

Swelling behaviour of isora/natural rubber composites in oils used in ...

Indian Academy of Sciences (India)

Unknown

Department of Polymer Science and Rubber Technology, Cochin University of Science and Technology,. Kochi 682 022 ... natural resources have prompted the composite industry to .... provided information on the interface strength, degree of.

About the cure kinetics in natural rubber/styrene Butadiene rubber blends at 433 K

International Nuclear Information System (INIS)

Mansilla, M.A.; Marzocca, A.J.

2012-01-01

Vulcanized blends of elastomers are employed in several goods mainly to improve physical properties and reduce costs. One of the most used blends of this kind is that composed by natural rubber (NR) and styrene butadiene rubber (SBR). The cure kinetic of these blends depends mainly on the compound formulation and the cure temperature and time. The preparation method of the blends can influence the mechanical properties of the vulcanized compounds. In this work the cure kinetic at 433 K of NR/SBR blends vulcanized with the system sulfur/TBBS (N-t-butyl-2-benzothiazole sulfenamide) is analyzed in samples prepared by mechanical mixing and solution blending. The two methods produce elastomer domains of NR and SBR, which present different microstructure due to the cure level attained during vulcanization. The cure kinetics is studied by means of rheometer tests and the model proposed by Kamal and Sourour. The analysis of the cure rate is presented and is related to the structure obtained during the vulcanization process.

About the cure kinetics in natural rubber/styrene Butadiene rubber blends at 433 K

Energy Technology Data Exchange (ETDEWEB)

Mansilla, M.A., E-mail: mmansilla@df.uba.ar [Laboratorio de Polimeros y Materiales Compuestos, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 1, C1428EGA Buenos Aires (Argentina); Marzocca, A.J. [Laboratorio de Polimeros y Materiales Compuestos, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 1, C1428EGA Buenos Aires (Argentina)

2012-08-15

Vulcanized blends of elastomers are employed in several goods mainly to improve physical properties and reduce costs. One of the most used blends of this kind is that composed by natural rubber (NR) and styrene butadiene rubber (SBR). The cure kinetic of these blends depends mainly on the compound formulation and the cure temperature and time. The preparation method of the blends can influence the mechanical properties of the vulcanized compounds. In this work the cure kinetic at 433 K of NR/SBR blends vulcanized with the system sulfur/TBBS (N-t-butyl-2-benzothiazole sulfenamide) is analyzed in samples prepared by mechanical mixing and solution blending. The two methods produce elastomer domains of NR and SBR, which present different microstructure due to the cure level attained during vulcanization. The cure kinetics is studied by means of rheometer tests and the model proposed by Kamal and Sourour. The analysis of the cure rate is presented and is related to the structure obtained during the vulcanization process.

Effect of cellulose nanocrystals from corn cob with dispersion agent polyvinyl pyrrolidone in natural rubber latex film after aging treatment

Science.gov (United States)

Harahap, H.; Ridha, M.; Halimatuddahliana; Taslim; Iriany

2018-02-01

This study about the resistance of natural rubber latex films using nanocrystals cellulose filler from corn cob waste by aging treatment. Corn cob used as organic filler composed of cellulose, hemicellulose, and lignin. Each component has a potential for reuse, such as cellulose. Cellulose from corn cob has potential application as a filler prepared by hydrolysis process using a strong acid. The producing of natural rubber latex films through coagulant dowsing process. This research started with the pre-vulcanization process of natural rubber latex at 70 °C and followed by process of vulcanization at 110 °C for 20 minutes. Natural rubber latex films that have been produced continued with the aging treatment at 70 °C for 168 hours. The mechanical properties of natural rubber latex films after aging treatment are the tensile strength, elongation at break, M100 and M300 have performed.

Host Plant and Leaf-Age Preference of Luprops tristis (Coleoptera: Tenebrionidae: Lagriinae: Lupropini: A Home Invading Nuisance Pest in Rubber Plantation Belts

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Sabu K. Thomas

2012-01-01

Full Text Available Massive seasonal invasion by the litter-dwelling beetle Luprops tristis, into residential buildings prior to monsoon rains, and their prolonged state of dormancy render them a very serious nuisance pest in rubber plantations in the Western Ghats in southern India. Feeding preferences of L. tristis towards leaf litter of seven trees co-occurring in rubber plantations, cashew (Anacardium occidentale, mango (Mangifera indica, jackfruit (Artocarpus heterophyllus, wild jack (Artocarpus hirsutus, cocoa (Theobroma cacao, cassia (Cassia fistula, sapota (Manilkara zapota and rubber (Hevea brasiliensis were analyzed with no-choice and multiple-choice leaf disc tests. Results showed that L. tristis is a generalist feeder with a defined pattern of preference, with the leaf litter of rubber being the most preferred followed by those of jackfruit and cocoa. Tender leaves were preferred over mature leaves except for cocoa and sapota. Equal preference towards tender and mature cocoa leaves, presence of patches of cocoa plantations and the scarce distribution of other host plants in rubber plantation belts leads to the proposal that in the absence of tender and mature rubber leaves, cocoa becomes the major host plant of L. tristis.

Genetic Determinism of Sensitivity to Corynespora cassiicola Exudates in Rubber Tree (Hevea brasiliensis).

Science.gov (United States)

Tran, Dinh Minh; Clément-Demange, André; Déon, Marine; Garcia, Dominique; Le Guen, Vincent; Clément-Vidal, Anne; Soumahoro, Mouman; Masson, Aurélien; Label, Philippe; Le, Mau Tuy; Pujade-Renaud, Valérie

2016-01-01

An indirect phenotyping method was developed in order to estimate the susceptibility of rubber tree clonal varieties to Corynespora Leaf Fall (CLF) disease caused by the ascomycete Corynespora cassiicola. This method consists in quantifying the impact of fungal exudates on detached leaves by measuring the induced electrolyte leakage (EL%). The tested exudates were either crude culture filtrates from diverse C. cassiicola isolates or the purified cassiicolin (Cas1), a small secreted effector protein produced by the aggressive isolate CCP. The test was found to be quantitative, with the EL% response proportional to toxin concentration. For eight clones tested with two aggressive isolates, the EL% response to the filtrates positively correlated to the response induced by conidial inoculation. The toxicity test applied to 18 clones using 13 toxinic treatments evidenced an important variability among clones and treatments, with a significant additional clone x treatment interaction effect. A genetic linkage map was built using 306 microsatellite markers, from the F1 population of the PB260 x RRIM600 family. Phenotyping of the population for sensitivity to the purified Cas1 effector and to culture filtrates from seven C. cassiicola isolates revealed a polygenic determinism, with six QTL detected on five chromosomes and percentages of explained phenotypic variance varying from 11 to 17%. Two common QTL were identified for the CCP filtrate and the purified cassiicolin, suggesting that Cas1 may be the main effector of CCP filtrate toxicity. The CCP filtrate clearly contrasted with all other filtrates. The toxicity test based on Electrolyte Leakage Measurement offers the opportunity to assess the sensitivity of rubber genotypes to C. cassiicola exudates or purified effectors for genetic investigations and early selection, without risk of spreading the fungus in plantations. However, the power of this test for predicting field susceptibility of rubber clones to CLF will have

Developments in rubber technology 2 synthetic rubbers

CERN Document Server

Lee, K

1981-01-01

This book is intended for those people who have a knowledge or understanding of rubber materials and processes but who wish to update their knowledge. It should be read in conjunction with Developments in Rubber Technology-l as that volume discussed developments in natural rubber and selected special purpose synthetic rubbers as well as additives. The authors have been selected for their expertise in each particular field and we, as editors, would like to express our appreciation to the individual authors and also to their companies. Such a book would be impossible to produce without such active cooperation as we have received. Volumes 1 and 2 of Developments in Rubber Technology cover rubbers which are processed and vulcanised in the traditional manner. It is appreciated that the omission of non-vulcanised rubber materials (the so­ called thermoplastic elastomers) will be unwelcome to many readers but it is intended, because of the size of the subject, to cover these materials in a subsequent volume. A.W. K...

Microstructure, molecular weight and thermal behavior of natural rubber (NR) from mangabeira (Hancornia speciosa)

International Nuclear Information System (INIS)

Santos, Expedito Flavio dos; Feitosa, Judith P.A.; Ricardo, Nagila M.P.S.

2001-01-01

The natural rubber (NR) from Hancornia speciosa contains characteristics that turns it a good alternative in elastomers supply. The NMR and IR spectra showed that the rubber of mangabeira is composed fundamentally by poly(1,4-cis-isoprene). The rubber molecular weight obtained by GPC and viscometry was 2,0x10 6 and 1,3x10 6 g/mol, respectively, in good agreement with the values determined for seringueira and manicoba NR. The glass transition temperature obtained by DSC (Tg = - 65 deg C) showed the mangabeira rubber is ideal to be utilized in regions of cold climate without compromising its mechanical properties. The rubber has also good thermal stability up to 213 deg C, as indicated by TG curves. This results indicated that the mangabeira NR can be effectively used in vulcanized articles or to be added to asphalt. (author)

Cercosporiose progression in the agroforestry consortium coffee-rubber trees

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Humberto Godoy Androcioli

2015-12-01

Full Text Available Cercospora coffeicola is one of the primary diseases that affect coffee plants. Studies indicate that shaded coffee plants reduce the incidence of this disease and that the management of trees and coffee plants arrangement influence in the dissemination of cercospora. The objective of this study was to evaluate the incidence and severity of C. coffeicola at different distances from double rows of rubber trees (Hevea brasiliensis muell. arg. at two different sunlight exposures (north and south. This study was conducted in Londrina, Parana, between 2008 and 2010, with adult plants of the IAPAR 59 cultivar (Coffea arabica L. grown at a spacing of 2.5 m x 1.0 m. The distances between the double rows of rubber trees were 13, 16 and 22 m, compared to plants grown under full sun. The disease incidence was assessed monthly by using a non-destructive method. This analysis was conducted on coffee leaves from the third and fourth pairs of two plagiotropic branches, on eight plants per plot, with five replications. These data were used to calculate the area under the curve for the incidence of the brown eye spot. The highest disease incidence occurred in the coffee plants grown under full sun, whereas lowest disease occurred on plants located at up to two meters away from double rows of rubber trees. The incidence of Cercospora leaf spot increased with the distance from the double rows of rubber trees. The results demonstrate that the mapping of cercospora incidence in shaded coffee plants is essential to determinate the best spacing and plants arrangement.

Hardness and swelling behaviour of epoxidized natural rubber/recycled acrylonitrile-butadiene rubber (ENR 50/NBRr) blends

Science.gov (United States)

Ahmad, Hazwani Syaza; Ismail, Hanafi; Rashid, Azura A.

2017-07-01

This recent work is to investigate the hardness and swelling behaviour of epoxidized natural rubber/recycled acrylonitrile-butadiene rubber (ENR 50/NBRr) blends. ENR 50/NBRr blends were prepared by two-roll mills with five different loading of NBRr from 5 to 35 phr. Results indicated that the hardness of ENR 50/NBRr blends increased as recycled NBR increased due to the improvement in crosslink density of the blends. Increasing NBRr content gives ENR 50/NBRr blends better resistance towards swelling. Higher degree of crosslinking will increase the swelling resistance and reduce the penetration of toluene into the blends. The presence of polar group in ENR 50 and NBRr give better hardness properties and swelling behaviour of the ENR 50/NBRr blends compared to the NR/NBRr blends.

Use of epoxidized natural rubber as a compatibilizer in silica-filled natural rubber tire tread compounds ; Verwendung von epoxydiertem Naturkautschuk als Verträglichkeitsvermittler in Zusammensetzungen aus kieselsäuregefülltem Naturkautschuk für Reifenlaufflächen

NARCIS (Netherlands)

Sengloyluan, K.; Sahakaro, Kannika; Noordermeer, Jacobus W.M.

2012-01-01

Silica-reinforced natural rubber (NR) tire tread compounds with epoxidized natural rubber (ENR) as a compatibilizer are investigated. ENR contents of 2.5-15.0 phr, with epoxide levels of 10, 38 and 51 mol%, are used. The addition of ENRs, especially ENR-38 and ENR-51, as compatibilizers decreases

Carbon Stocks across a Fifty Year Chronosequence of Rubber Plantations in Tropical China

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Chenggang Liu

2017-06-01

Full Text Available Transition from forest to rubber (Hevea brasiliensis Muell. Arg. plantation has occurred in tropical China for decades. Rubber has been planted on 1 million ha to provide raw materials to the rubber industry. The role of various-aged rubber plantations in carbon (C sequestration remains unclear. The biomass C accumulation including latex C and C distribution in soil of five different-aged stands (7, 13, 19, 25 and 47 years old were examined. The total biomass C stock (TBC and total net primary productivity (NPPtotal, whether with or without latex C, had a close quadratic relationship with stand age. Regardless of stand age, around 68% of the C was stored in aboveground biomass, and NPPlatex contributed to approximately 18% of C sequestration. Soil organic carbon stock in the 100-cm depth remained relatively stable, but it lost about 16.8 Mg ha−1 with stand age. The total ecosystem C stock (TEC across stands averaged 159.6, 174.4, 229.6, 238.1 and 291.9 Mg ha−1, respectively, of which more than 45% was stored in the soil. However, biomass would become the major C sink rather than soil over a maximal rubber life expectancy. Regression analysis showed that TEC for rubber plantation at 22 years is comparable to a baseline of 230.4 Mg ha−1 for tropical forest in China, and would reach the maximum value at around 54 years. Therefore, rubber plantation can be considered as alternative land use without affecting net forest ecosystem C storage. In addition to the potential C gains, a full set of ecosystem and economic properties have to be quantified in order to assess the trade-offs associated with forest-to-rubber transition.

Rubber seed oil: A potential renewable source of biodiesel for sustainable development in sub-Saharan Africa

International Nuclear Information System (INIS)

Onoji, Samuel E.; Iyuke, Sunny E.; Igbafe, Anselm I.; Nkazi, Diakanua B.

2016-01-01

Highlights: • Sub-Saharan Africa countries have about 251 million rubber trees with the capacity to produce over 16 kilo ton of biodiesel. • Rubber seed oil has wider industrial applications and its biodiesel properties compete favorably with other non-edible oils. • Rubber seed oil is a sustainable and affordable source of biodiesel for sub-Saharan Africa development. • Plantain peels that are in abundance in sub-Saharan Africa is a source of base catalyst for the transesterification of rubber seed oil. • This is no regulatory framework and bioenergy policy in sub-Saharan Africa on the use of waste rubber seeds. - Abstract: The global energy demand is currently met by the use of non-renewable fossil fuels. The challenges of non-availability of these fuels in the future, instability in prices of crude oil and its negative environmental impacts, stimulated researchers in the global community in search of renewable energies for replacement of fossil fuels in future. Biodiesel has been identified as a good complement and plausible replacement of fossil diesel because of the overwhelming characteristic properties similar to fossil diesel in addition to its good lubricity, biodegradability, non-toxicity and eco-friendliness when used in diesel engines. The production of biodiesel from edible vegetable oils competes with food consumption and consequently high cost of food and biodiesel. Studies have shown that rubber seed contains 35–45 wt.% oil which portrays a better competitor to other non-edible oil bearing plants in biodiesel production. Biodiesel produced from non-edible rubber seed oil (RSO) is an attractive option for the sustainable development of sub-Saharan Africa (SSA) countries that depend heavily on fossil diesel. The application of abundant plantain (Musa paradisiacal) peels considered as waste in SSA countries as heterogeneous base catalyst in RSO biodiesel production will further reduce the cost of biodiesel. Rubber trees (Hevea brasiliensis

Degradation of non-vulcanized natural rubber - renewable resource for fine chemicals used in polymer synthesis

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Alexander Fainleib

2013-01-01

Full Text Available In the current scenario, there is growing interest in the products of degradation of rubber (natural and synthetic for specific applications in different industry sectors, whose benefits in replacing conventionally used products are mainly related to sustainability. Since the degradation products of rubber can be used in different areas, several research groups may have the interest aroused by these products, but are not familiar with the aspects related to the chemical behavior of rubber. This review aims to bring together the key information in the published literature on the degradation of natural rubber, emphasizing metatheses reactions, oxidative damage and splitting of the double bond, in order to serve as a reference source for researchers from different fields interested in obtaining such kind of products. The structures and properties as well as additional chemical transformations resulting in oligomers of isoprene, functionalised oligomers and polymers based on both are also described.

Natural rubber, a potential alternative source for the synthesis of renewable fuels via Hydrous Pyrolysis

Science.gov (United States)

Ahmad, N.; Dayana, S. A. S.; Abnisa, F.; Mohd, W. A. W. D.

2018-03-01

Natural rubber is a humid agricultural harvest, which mostly contains hydrocarbon cis-1, 4-Poly isoprene. Through depolymerisation technology, the natural rubber can be changed into liquid product, and then it can be subsequently utilized as a fuel or chemical feedstock. This article aims to provide an outlook on the natural rubber and its sources, which are available globally. Numerous depolymerisation processes, which include pyrolysis, gasification, chemical degradation, catalytic cracking and hydrogenation, were introduced in this paper, while the focus of discussion was emphasized on the hydrous pyrolysis process. Many studies have shown that the use of hydrous pyrolysis able to improve the depolymerisation process, e.g. the raw material can be feed without drying, the process can be carried out at lower temperature, only the water is used as the reaction medium, and it is easy to separate the water from oil product. The effect of operating parameters such as temperature, water to rubber mass ratio, reaction time and type of gases on the product yield and composition were reviewed in this paper. In addition, this paper also highlighted the eco-friendly and economic viability of the hydrous pyrolysis process.

New Green Polymeric Composites Based on Hemp and Natural Rubber Processed by Electron Beam Irradiation

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Maria-Daniela Stelescu

2014-01-01

Full Text Available A new polymeric composite based on natural rubber reinforced with hemp has been processed by electron beam irradiation and characterized by several methods. The mechanical characteristics: gel fraction, crosslink density, water uptake, swelling parameters, and FTIR of natural rubber/hemp fiber composites have been investigated as a function of the hemp content and absorbed dose. Physical and mechanical properties present a significant improvement as a result of adding hemp fibres in blends. Our experiments showed that the hemp fibers have a reinforcing effect on natural rubber similar to mineral fillers (chalk, carbon black, silica. The crosslinking rates of samples, measured using the Flory-Rehner equation, increase as a result of the amount of hemp in blends and the electron beam irradiation dose increasing. The swelling parameters of samples significantly depend on the amount of hemp in blends, because the latter have hydrophilic characteristics.

Safety Evaluation Test on Human for Radiation Pre vulcanised Natural Rubber Latex (RVNRL)

International Nuclear Information System (INIS)

Pairu Ibrahim; Wan Manshol Wan Zain; Chai, Chee Keong; Sofian Ibrahim; Saadiah Sulaiman; Sharifah Ismail

2010-01-01

This paper discussed about clinical test conducted to determine safety evaluations on human for latex examination gloves and latex films made from Radiation Vulcanized Natural Rubber Latex (RVNRL). Two types of test were being adopted which are i) Modified Draize-95 test and ii) Patch Test on Sensitized Individuals. Modified Draize-95 test was conducted on 200 non-sensitized human subjects and Patch Test on Sensitized Individuals was conducted on 25 individuals who are allergic to the defined major chemical sensitizer presents in natural rubber product. It was found that Modified Draize-95 test has prove that there is no clinical evidence on the presence of residual chemical additives at the level that may induce Type IV allergy in the un sensitized general user population in the RVNRL gloves. Meanwhile Patch Test on Sensitized Individuals has proved that the patch test conducted using the test article on 25 individuals who are allergic to the defined major chemical sensitizers present in natural rubber products, thiuram, carbamates or thiazoles produced a negative response, meeting the pre requirement for the claim of reduced reaction-inducing potential. (author)

The Effect of Novel Binary Accelerator System on Properties of Vulcanized Natural Rubber

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Moez Kamoun

2009-01-01

Full Text Available The mechanical properties, curing characteristics, and swelling behaviour of vulcanized natural rubber with a novel binary accelerator system are investigated. Results indicate that the mechanical properties were improved. Crosslinking density of vulcanized natural rubber was measured by equilibrium swelling method. As a result, the new binary accelerator was found to be able to improve both cure rate and crosslinking density. Using the numerical analysis of test interaction between binary accelerator and operational modelling of vulcanization-factors experiments, it can be concluded that the interaction (Cystine, N-cyclohexyl-2-benzothiazyl sulfenamide was significant and the optimum value of binary accelerator was suggested, respectively, at levels 0 and +1.

Evaluation of different drought stress periods on Hevea brasiliensis ...

African Journals Online (AJOL)

As global demand for natural rubber increases, a major challenge for cultivation of rubber plants is their inability to withstand unfavorable environmental conditions in the context of global climate change. Drought remains one of the most biologically demanding and ecologically limiting factors among all environmental ...

Study on preparation of new antioxidants for radiation vulcanized natural rubber latex product. Antioxidant from keratin

International Nuclear Information System (INIS)

Nguyen Quoc Hien; Nguyen Van Toan; Vo Tan Thien; Le Hai

2000-01-01

The thermo-oxidative aging resistance of radiation vulcanization of natural rubber latex (RVNRL) products should be adequately by using suitable antioxidants or new kind of effective antioxidant. This work presents the results of preparation of natural antioxidant from hair keratin. Characteristics and effectiveness of resultant antioxidant are also presented. The results obtained indicates that antioxidant made from hair keratin is safe and effective for rubber products from RVNRL. (author)

Preparation and evaluation of some investigated natural and acrylonitrile rubber vulcanizations for physiotherapeutic purposes

International Nuclear Information System (INIS)

Helaly, F.M; El-Sawy, S.M.

2005-01-01

A trial was made to design and prepare rubber article that can be used to reactivate, strengthen and reinforce the hand muscles and fingers which had suffered from trouble movement.The investigated rubber article was prepared from natural and acrylonitrile rubber formulations. These formulations were processed in the form of compounds which contain significant quantities of fillers as Hisil, CaCO 3 and TiO 2 .The rheological characteristics and physicochemical properties of the vulcanizations were determined according to standard tests. It was found that it is possible to prepare the designated rubber article for the desired purpose. The test results show that the prepared rubber article has a good chemical resistant against acid, alkali, and salt. Also it possesses high resistance to deterioration and deformation. The prepared article has an ability to retain its elastic property after the action of compressive forces at 70 degree C for 24 hours.This was conformed with applied commercial hand exercise therapeutic article

Maillard Reaction in Natural Rubber Latex: Characterization and Physical Properties of Solid Natural Rubber

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S. Montha

2016-01-01

Full Text Available Maillard reaction in Natural Rubber (NR latex was investigated by treating fresh NR latex with glutaraldehyde (C5H8O2 in amounts of 0, 50, 100, and 200 mmol/kg of latex. Protein cross-linking in fresh NR latex and solid NR was confirmed by using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE and attenuated total reflection infrared (ATR-IR spectroscopy, respectively. It was found that degree of protein cross-linking in NR increased with increasing C5H8O2 concentration. Physical properties of untreated and treated NR substances in terms of gel content, initial Wallace plasticity (P0, plasticity retention index (PRI, Mooney viscosity, and tensile strength were carefully explored. Results clearly showed that the Maillard cross-linking of proteins had remarkable effect on bulk NR properties, that is, solvent resistance, hardness, resistance to oxidation, rheological behavior, and resistance to stretching out.

Use of a modified natural-rubber phantom for radiotherapy dosimetry measurements

International Nuclear Information System (INIS)

Bradley, D.A.; Ng, K.-H.; Aziz, Y.B.

1988-01-01

The utility of a phantom material, based on SMR(L) [Standard Malaysian Rubber] grade natural rubber and a formulation used for the proprietary rubber phantom-material, Temex, has been examined for the 1-MeV photon-energy range using γ radiation from a 60 Co source. Measurement has also been performed with 60-keV photons using the radionuclide 241 Am. At photon-therapy energy levels the measured response, when compared with tabulated central-axis percentage depth doses for defined measuring conditions, produces everywhere (in the range 1-19 cm depth) better than 2% deviation. The favourable measured response characteristics combined with the ease of processing and casting the phantom material provide the basis for useful radiotherapy machine calibration and anthropomorphic dosimetry measurements. The measured mass-attenuation coefficient, at 60 keV, of 0.204 cm 2 g -1 (± 3%) is in close agreement with tabulated values for water (0.2055 cm 2 g -1 ). (author)

Properties of natural rubber composites with structurally different clay intercalable surfactants

Czech Academy of Sciences Publication Activity Database

Sedničková, M.; Jochec-Mošková, D.; Janigová, I.; Kronek, J.; Jankovič, L.; Šlouf, Miroslav; Chodák, I.

2017-01-01

Roč. 24, č. 7 (2017), s. 1-13, č. článku 105. ISSN 1022-9760 Institutional support: RVO:61389013 Keywords : composite * natural rubber * clay Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.615, year: 2016

Study on Pollen Quality and Quantity as Protein Source of Honeybee Apis mellifera In Rubber Plantation Area (Hevea brasiliensis

Directory of Open Access Journals (Sweden)

Sri Minarti

2009-08-01

The conclusion of this research is during migratory beekeeping in the area of rubber plantation, bees get pollen low amounts of protein and amino acid levels below the requirement. Keywords : Pollen, Protein, Amino Acids, Honey Bee, Rubber

Silane grafted natural rubber and its compatibilization effect on silica-reinforced rubber tire compounds

Directory of Open Access Journals (Sweden)

K. Sengloyluan

2017-12-01

Full Text Available Natural Rubber (NR grafted with 3-octanoylthio-1-propyltriethoxysilane (NXT was prepared by melt mixing using 1,1′-di(tert-butylperoxy-3,3,5-trimethylcyclohexane as initiator at 140 °C with NXT contents of 10 and 20 parts per hundred rubber [phr] and initiator 0.1 phr. The silane grafted on NR molecules was confirmed by Fourier transform infrared (FTIR, proton nuclear magnetic resonance (1H-NMR and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDX. Based on 1H-NMR, the use of 10 and 20 phr (parts per hundred resin of silane resulted in grafted NXT onto NR of 0.66 and 1.32 mol%, respectively, or a grafting efficiency of approx. 38%. The use of NXT-grafted NR as compatibilizer in silica-filled NR compounds, to give a total amount of NXT in both grafted and non-grafted forms in the range of 0.8–6.1 wt% relative to the silica, decreases the Mooney viscosity and Payne effect of the compounds, improves filler-rubber interaction, and significantly increases the tensile properties of the silica-filled NR-compounds compared to the non-compatibilized one. At the same silane-content, the use of silane-grafted NR gives slightly better properties than the straight use of the same silane. With sulfur compensation, the use of NXT-grafted-NR with about 6 wt% NXT relative to the silica gives technical properties that reach the levels obtained for straight use of bis-(3-triethoxysilyl-propyltetrasulfide (TESPT at 8.6 wt% relative to the silica.

Effect of Antioxidants on Radiation Vulcanization Natural Rubber Latex (RVNRL) Film

International Nuclear Information System (INIS)

Syuhada Ramli; Sofian Ibrahim; Muhammad Saiful Omar

2015-01-01

This paper presents the results on the effects of different antioxidants used in Radiation Vulcanization Natural Rubber Latex (RVNRL)) films between 0 to 10 weeks monitoring. Antioxidants used for the RVNRL formulation were Aquanox LP, Irganox and Wingstay L. Color difference evaluation by using Chroma Meter CR-400 found that RVNRL film with Irganox was the most stained yellowish after 8 weeks monitoring. Tensile strength for RVNRL with Aquanox found achieved the optimum strength between 25.4 to 27.13 mPa. The scanner electron microscopic (SEM) indicated more Aquanox molecules to penetrate and interact with the rubber molecule, thus becoming more effective inhibitor against its oxidative ageing. (author)

Physical-biopolymer characterization of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) blended with natural rubber latex

Energy Technology Data Exchange (ETDEWEB)

Kuntanoo, K., E-mail: thip-kk@hotmail.com [Graduate School of Khon Kaen University, Khon Kaen, 40002 Thailand (Thailand); Promkotra, S., E-mail: sarunya@kku.ac.th [Department of Geotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002 Thailand (Thailand); Kaewkannetra, P., E-mail: paknar@kku.ac.th [Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002 Thailand (Thailand)

2015-03-30

A biopolymer of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) is blended with bio-based materials, natural rubber latex, to improve their microstructures. The various ratios between PHBV and natural rubber latex are examined to develop their mechanical properties. In general, physical properties of PHBV are hard, brittle and low flexible while natural rubber (NR) is presented itself as high elastic materials. Concentrations of the PHBV solution are constituted at 1%, 2% and 3% (w/v). The mixtures of their PHBV solutions to natural rubber latex are produced the blended films in three different ratios of 4:6, 5:5 and 6:4, respectively. They are characterized by appearance analyses which are the scanning electron microscope (SEM), universal testing machine (UTM) and differential scanning calorimetry (DSC). The SEM photomicrographs of the blended films and the controlled PHBV can provide the void distribution in the range of 12-14% and 19-21%, respectively. For mechanical properties of the blended films, the various elastic moduli of 1%, 2% and 3% (w/v) PHBV are the average of 773, 956 and 1,007 kPa, respectively. The tensile strengths of the blends increase with the increased concentrations of PHBV, similarly trend to the elastic modulus. The crystallization and melting behavior of unmixed PHBV and the blends are determined by DSC. Melting transition temperatures (T{sub m}) of the unmixed PHBV are stated two melting peak at 154°C and 173°C. Besides, the melting peaks of the blends alter in the range of 152-156°C and 168-171°C, respectively. According to morphology of the blends, the void distribution decreases twice compared to the unmixed PHBV. The results of mechanical properties and thermal analysis indicate that the blended PHBV can be developed their properties by more resilient and wide range of temperature than usual.

Rubber compounding and processing

CSIR Research Space (South Africa)

John, MJ

2014-06-01

Full Text Available This chapter presents an overview on the compounding and processing techniques of natural rubber compounds. The introductory portion deals with different types of rubbers and principles of rubber compounding. The primary and secondary fillers used...

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African Journals Online (AJOL)

Dr Osondu

2011-10-05

Oct 5, 2011 ... plantation is increasing in the rainforest zone of south southern Nigeria; however, the build-up of soil organic matter following ... matter in the soil during the course of forest regeneration from degraded abandoned rubber plantation. (Hevea brasiliensis). ..... microbial respiration. Nature 382:445-448.

Proteins and amino acids as biobased polymer modifiers

Science.gov (United States)

Natural rubber (NR) is a critical agricultural material vital to industry, medicine, and defense, yet global supply is largely limited to latex from Hevea brasiliensis cultivated in tropical regions. Guayule (Parthenium argentatum), a woody desert shrub indigenous to the U.S. and Mexico, is under de...

Dynamics of root and leaf decomposition in chronosequence of rubber plantation (Hevea brasilensis) in SW China

International Nuclear Information System (INIS)

Moazzam, N.S.; Yiping, Z.; Liqing, S.; Moazzam, N.S.

2018-01-01

This study highlighted the dynamics of stand parameters as well as root and leaf litter decomposition in the chronosequence (49, 32, 24 and 12 years old plantations established in the year 1965, 1982, 1990 and 2002) of the rubber plantation in Xishuangbanna SW China. Litter trappers were installed on the study site to collect the leaf litter and litter bag experiment was carried out to investigate the rate of root and leaf litter decomposition. The study revealed significant variation of stand characteristics during the decomposition process. The monthly litter fall and root biomass (all categories; kg m-3) showed positive correlation with stand characteristics and age. Remaining leaf litter mass % in the litter bags reduced with the passage of time and was significantly different in the chronosequence. The highest root decomposition rate (55%) was shown by fine roots and minimum (32%) by coarse roots during the study period. The investigations on elemental composition of the leaf and root provides basic important information for rate of nutrient cycle along with decomposition rate in rubber plantation and result are quite helpful for simulating the below ground carbon stock of rubber plantation in SW China. (author)

Properties and Characterization of Kenaf-Filled Natural Rubber Latex Foam

Directory of Open Access Journals (Sweden)

Ahmad Fikri Abdul Karim

2015-12-01

Full Text Available Kenaf powder was incorporated with natural rubber latex (NRL compound and foamed to make natural rubber latex foam (NRLF by using a well known technique called the Dunlop method. Different loadings of kenaf powder were added to NRL compound and was foamed to make NRLF. The mechanical properties, density, compression, thermal, and micro-structural characterization of control NRLF and kenaf incorporated NRLF were studied. Increasing content of kenaf reduced the tensile strength, elongation at break, and compressive strength of a NRLF. Modulus at 100% elongation and density of the NRLF increased with an increase in filler loading. Higher kenaf loading indicated higher elasticity of kenaf-filled NRLF, but the recovery percentage of kenaf-filled NRLF decreased with increasing kenaf loading. From thermogravimetric analysis (TGA result, an increase in the amount of kenaf loading from 1 to 7 phr increased the thermal stability of kenaf-filled NRLF. Morphological and micro-structural characterization performed by using scanning electron microscopy (SEM showed that kenaf powder filled up the micro-sized pores in the open cell structure of kenaf-filled NRLF.

PROPERTIES TYRE TREAD RUBBERS DEPENDING ON PARTICULARITY OF RUBBER COMPOUND

Directory of Open Access Journals (Sweden)

Z. S. Shashok

2014-01-01

Full Text Available Summary. The results of studies of the elastomeric compositions based on natural rubber containing curatives different ratio "curing agent : vulcanization accelerator" listed in this article. Influence of the composition of the vulcanizing group on stress-strain and elastic- deformation properties of tire tread rubber was installed. It has been shown that a significant effect on thermo-oxidative aging of vulcanizates was the composition of the vulcanizing group. Results of studies resistance tread rubber to exposure to elevated temperatures were presented . Vulcanizates differing type and density by varying the cross-linking ratio of "curing agent : vulcanization accelerator" were obtained . Research results in the formation of rubber resistance and crack growth at different temperatures were presented. Revealed that the best education and resistance to tear propagation under normal conditions characterized by rubber ratio "curing agent : vulcanization accelerator" equal to 1.5:1. It has been established that a dynamic endurance study rubbers depends largely on the nature and concentration of the cross-linking cross-links and movable promote increase efficiency due to the grid and reduce the sulfidity rearrangement. During loading mode alternating deformations at elevated temperatures lability of polysulfide bonds negatively affects the performance of rubber, and the decisive role of providing strength and thermal cross-linking. It is shown that the performance of the spatial grid rubbers allow indirectly judge the dynamic vulcanizates endurance and predict performance rubbers at elevated temperatures under conditions of repeated cyclic deformation. Revealed that the vulcanizing system containing sulfur and vulcanization accelerator TBBS 1:2, promotes the formation of the optimal structure of vulcanized rubber , which provides the best resistance to repeated cyclic deformations in the operating temperatures of the tire.

Viscoelastic and thermal properties of woven sisal fabric reinforced natural rubber biocomposites

CSIR Research Space (South Africa)

John, MJ

2009-01-01

Full Text Available This study explores the dynamic mechanical behavior of woven sisal fabric reinforced natural rubber composites. The influence of chemical modification on the viscoelastic properties has also been determined. Moreover, the effect of frequency...

High concentrations of natural rubber latex allergens in gloves used ...

African Journals Online (AJOL)

Introduction. Gloves made of natural rubber latex (NRL) are commonly used by healthcare workers because of their good qualities. However, allergic reactions to latex allergens are still commonly reported. Objective. To measure the concentrations of Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 allergens in gloves used by a ...

The effect of proteins on the aging properties of radiation vulcanized natural rubber latex

International Nuclear Information System (INIS)

Abad, L.V.

1993-01-01

The effect of natural rubber latex (NRL) proteins on the aging properties of NRL films was investigated. SDS-PAGE electrophoresis of the rubber proteins in NRL (Sri-Lanka) indicated a total of 18 proteins. A sharp decrease in tensile strength was observed after aging when NRL films were leached in 1% NH 4 OH. However, when these films were soaked in ethanol prior to leaching, the aging properties approximated those of the unleashed samples. Electrophoretic analysis of the proteins present in the NH 3 extracts of leached RVNRL films showed a high concentration of the protein herein. This protein was not found in the NH 3 extracts of ethanol soaked films. NRL proteins were shown to decelerate the aging process of Radiation Vulcanized Natural Rubber Latex (RVNRL) films. Among the proteins, herein exhibited good anti-aging properties. The hydrolyzates from NR proteins also enhanced considerably the aging properties of RVNRL. (auth.). 8 refs.; 40 figs.; 30 tabs

Observation of immobile regions in natural rubber at ambient temperature by solid-state C-13 CP/MAS NMR spectroscopy

DEFF Research Database (Denmark)

Larsen, F.H.; Rasmussen, T.; Pedersen, Walther Batsberg

1999-01-01

Employing C-13 CP/MAS NMR spectroscopy, the existence of immobile regions in natural rubber (cis-1,4-polyisoprene) corresponding to a few percent of the monomer units has been detected at ambient temperature. For synthetic rubbers no immobile regions have been detected at all. Applying different...... physical and chemical treatments to natural rubber it is shown that mastication, gamma-irradiation, and increasing the temperature, slightly above the ambient, reduce the amount of immobile regions. (C) 1999 Elsevier Science Ltd. All rights reserved....

Properties of rubber blends based on natural rubber loaded with different fillers and cured by gamma radiation

International Nuclear Information System (INIS)

Mohamed, R.M.

2011-01-01

In this investigation system styrene butadiene rubber (1502 type) and natural rubber were blended in different ratios namely, NR/SBR (0/100), NR/SBR (25/75), NR/SBR (50/50), NR/SBR (75/25) and NR/SBR (100/0). All the samples were subjected to gamma irradiation dose up to 250 kGy. The improvement in the mechanical properties, physico-mechanical properties and thermal properties was followed as a function of irradiation dose and blend ratio. The SBR /NR (50/50) blend with reasonable properties were filled with 40 p hr of Hisil (highly fined silicon), HAF carbon black (high abrasion furnace), TiO 2 titanium dioxide and clay; the reinforcing ability of these fillers was found to follow the order: Hisil > HAF carbon black > Clay > TiO 2 The effect of different kinds of enhancing agents (coagent) namely: N, N- methylene di acrylamide (MDA), trimethylol propane tri methacrylate (TMPTMA) and tetramethylol - methane tetraacrylate (TMMT) on the properties of the obtained composites as a function of irradiation dose was studied. The data obtained showed that the enhancement character of the co agents follow the order: TMMT >TMPTMA > MDA >unenhanced composites. This investigation showed also the effect of gamma irradiation on improving the above mentioned properties in the presence of filler and co agents. Moreover, radiation dose at 100 kGy is sufficient enough for obtained the desired properties. The obtaining composites can be used in many industrial applications such as radio controlled model race car tires to footwear applications; the SBR component adds the toughness while the natural rubber provides superior resilience and energy return when used in footwear.

Styrene grafted natural rubber reinforced by in situ silica generated via sol–gel technique

Energy Technology Data Exchange (ETDEWEB)

Sittiphan, Torpong [Program of Petrochemistry and Polymer Sciences, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Prasassarakich, Pattarapan [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Poompradub, Sirilux, E-mail: sirilux.p@chula.ac.th [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand)

2014-02-15

Highlights: • Sol–gel reaction by NR latex was the absence of use of organic solvent and base catalyst. • Well dispersed in situ formed silica particles in the rubber matrix were obtained. • In situ silica was better to improve mechanical properties of rubber vulcanizates. -- Abstract: The filling of styrene graft natural rubber (ST-GNR) with in situ formed silica was performed using the sol–gel reaction via the latex solution method. The mechanical properties of ST-GNR/NR vulcanizate were improved when using the in situ formed silica to levels higher than those obtained with the commercial ex situ formed silica filled ST-GNR/NR vulcanizates at a comparable silica content of 12 parts by weight per hundred parts of rubber. Transmission electron microscopy analysis revealed that the in situ silica particles were small (∼40 nm diameter) and well dispersed, while the commercial silica particles were larger (∼60 nm diameter) and markedly agglomerated in the rubbery matrix. The mechanical properties of the composites prepared via both the solid rubber and latex solution methods were comparable.

Properties of Natural Rubber-Based Composites Containing Fullerene

Directory of Open Access Journals (Sweden)

Omar A. Al-Hartomy

2012-01-01

Full Text Available In this study the influence of fullerenes in concentrations from 0.5 to 1.5 phr on both the vulcanization characteristics of the compounds and physicomechanical, dynamic, and dielectric properties and thermal aging resistance of nanocomposites on the basis of natural rubber has been investigated. The effect of the filler dispersion in the elastomeric matrix has been also investigated. Neat fullerene and the composites comprising it have been studied and characterized by scanning electron microscopy (SEM and transmission electron microscopy (TEM.

Mechanism of n-butyl acrylate sensitization action in radiation vulcanization of natural rubber latex

International Nuclear Information System (INIS)

Sabharwal, S.; Chaudhari, C.V.; Bhardwaj, Y.K.; Majali, A.B.; Das, T.N.

1996-01-01

In order to understand the role of n-butyl acrylate (nBA) in radiation vulcanization of natural rubber latex, pulse radiolysis technique has been utilized to study the reactions of the transient species produced by reaction of OH . , e- aq and H . atoms with nBA in aqueous solutions. The results show that transients produced by reaction of e- aq with nBA alone are capable of propagating the polymerization reaction and enhance the vulcanization process. These results have been further confirmed by studying the effect of electron scavengers on the vulcanization behaviour of natural rubber latex in presence of nBA. (author). 3 refs., 3 figs

Properties of organo-clay/natural rubber nanocomposites: effects of organophilic modifiers

Czech Academy of Sciences Publication Activity Database

Hrachová, J.; Komadel, P.; Jochec-Mošková, D.; Krajči, J.; Janigová, I.; Šlouf, Miroslav; Chodák, I.

2013-01-01

Roč. 127, č. 5 (2013), s. 3447-3455 ISSN 0021-8995 R&D Projects: GA ČR GAP205/10/0348 Institutional research plan: CEZ:AV0Z40500505 Keywords : nanocomposite s * natural rubber * morphology Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.640, year: 2013

Radiation vulcanised natural rubber latex (RVNRL) market and challenges

International Nuclear Information System (INIS)

Wan Manshol Wan Zin; Najib Mohamad Zakey; Chai Chee Keong

2000-01-01

RVNRL has the required properties and proven useful for the manufacturing of examination gloves, balloons and finger cots at industrial scale. To date only RVNRL finger cots are available in the market. Problems and challenges for the market of other products are identified. Further success in the on going research activities will be the reference for more applications of RVNRL in the relevant industry to produce natural rubber latex products of more competitive values

The Effect of Minarex B Oil and Gamma Irradiation on the Mechanical Properties of Vulcanized Natural Rubber-LDPE Mixture for Shoe Sole

International Nuclear Information System (INIS)

Sudradjat Iskandar; Isni Marliyanti

2004-01-01

To obtain the optimum concentration of minarex B oil and gamma irradiation dose on natural rubber compound for shoe sole, study on the effect of minarex B oil and gamma radiation on the mechanical properties of vulcanized natural rubber-LDPE mixture has been done. Natural rubber was masticated and mixed with additive and filler using two-roll machine, at 120 o C of forward roll and 100 o C of backward roll, with rotation speed of 18 rpm. The additives added with irganox 1076, paraffin wax, stearic acid, and minarex B oil, while fillers used were polyethylene (LDPE) and calcium carbonate. Minarex B oil mixed was vary such as 5, 10 and 20 phr (part per hundred of rubber). The amount of filler and other additives mixed was not varied. The natural rubber film was obtained by pressing the mixture using hot and cold press machine at 135 o C and room temperature for about 3 minutes. The film then irradiated with gamma rays from cobalt-60 source, at the doses of 150, 300, and 500 kGy. The results show that the mechanical properties of natural rubber vulcanized decreases by increasing minarex B oil, and increases by increasing of irradiation dose. The concentration optimum of minarex B oil in the natural rubber compound for shoe sole and irradiation dose about 5 phr and 300 kGy were agree with SII 0944-84. (author)

Thermal, mechanical, and moisture absorption properties of egg white protein bioplastics with natural rubber and glycerol.

Science.gov (United States)

Jones, Alexander; Zeller, Mark Ashton; Sharma, Suraj

2013-07-03

Petroleum-based plastics have many drawbacks: the large amount of energy required to produce the plastic, the waste generated as a result of plastic production, and the accumulation of waste due to slow degradation rate. It is because of these negative attributes of conventional plastic use that attention is being focused on environmentally friendly plastics from alternative sources. Albumin protein provides one possible source of raw material, with inherent antimicrobial properties that may make it suitable for medical applications. We conducted this study to investigate the various bioplastic properties of the albumin with the use of three plasticizers - water, glycerol, and natural rubber latex. Based on results, 75:25 albumin-water, 75:25 albumin-glycerol, and 80:20 albumin-natural rubber were the best blending ratios for each plasticizer for a subsequent time study to determine water stability, with the 80:20 albumin-natural rubber blend ratio having possessed the best thermal, tensile, and viscoelastic properties overall.

STUDIES ON NATURAL WEATHERING OF RATTAN POWDER-FILLED NATURAL RUBBER COMPOSITES

Directory of Open Access Journals (Sweden)

Komethi Muniandy,

2012-07-01

Full Text Available This article investigates the effect of natural weathering on mechanical and morphological properties of rattan powder-filled natural rubber (NR composites as a function of filler loading and silane coupling agent. The rattan powder samples in the range of 0 to 30 phr were compounded with NR using a laboratory size two-roll mill. The natural weathering test was carried out for six months. The degradation of the samples was evaluated by performing a tensile test, a Fourier transform infrared spectroscopy (FTIR, and a scanning electron microscopy (SEM test. The results indicated that after natural weathering, an increase in stress at 100% elongation (M100 can be seen for samples without the silane coupling agent, whilst M100 was reduced for samples with silane coupling agent. A drastic reduction in tensile strength and elongation at break were observed for all samples due to the photo-oxidation process that occurred during the degradation of the samples. The extent of degradation on the samples’ surfaces and the presence of oxygenated products were confirmed by SEM and FTIR studies, respectively.

Exploiting epoxidized natural rubber latex (ENRL) as a starting raw material for latex-based products

Science.gov (United States)

Siti Nor Qamarina, M.; Fatimah Rubaizah, M. R.; Nurul Suhaira, A.; Norhanifah, M. Y.

2017-12-01

Epoxidized natural rubber latex (ENRL) is a chemically modified natural rubber latex produced from epoxidation process that involves usage of organic peracids. Conversion of the ENRL into dry rubber products has been known to exhibit many beneficial properties, however limited published works were found on diversifiying the ENRL latex-based products applications. In this preliminary work, different source of raw materials and neutralization systems were investigated. The objective was to explore possibilities in producing distinctive ENRL. Findings have demonstrated that different source of raw materials and neutralization systems influenced the typical ENRL specifications, stability behavior and particle size distribution. Morphological observations performed on these ENRL systems appeared to agree with the ENRL characteristics achieved. Since experimenting these two main factors resulted in encouraging ENRL findings, detailed work shall be further scrutinized to search for an optimum condition in producing marketable ENRL specifically for latex-based products applications.

Trialed production of low protein irradiated natural rubber latex in factory scale by gamma irradiation technique

International Nuclear Information System (INIS)

Utama, Marga; Herwinarni, S.; Halik, H.M.; Siswanto; Suharyanto; Syamsu, Y.; Handoko, B.

2006-01-01

Four tons fresh field natural rubber latex (FNRL) with total solid content 30% were added with 2 phr (part hundred ratio of rubber) normal butyl acrylate (nBA) then irradiated by gamma rays at 25 kGy. The irradiated FNRL was centrifuged, then the properties of irradiated centrifuged natural rubber latex (INRL) and its film were measured before and after storage for 5 months. It is found that the INRL is stable latex during storage in 5 months, with lowest protein, and free nitrosamine content. The tensile strength of INRL film was 24-27 MPa, and modulus 600% was 1,5-2,0 MPa, elongation at break was 900%, and hardness was 27-29 Shore A, while the extractable protein content less than 100 μg/g. (author)

Effect of rootstock on the scion of Hevea brasiliensis through metabolic analysis of latex samples by 1H NMR

Directory of Open Access Journals (Sweden)

Eduardo Sanches Pereira do Nascimento

2011-01-01

Full Text Available In this study, the effect of rootstock on grafting through metabolomic analysis of latex (Hevea brasiliensis samples was verified by 1H nuclear magnetic resonance (NMR and multivariate data analysis. Sixteen metabolites present in the latex cytosol were characterized by NMR. PCA analysis showed that the latex samples of the RR and GR groups can be differentiated. The GR group samples present a metabolic profile similar to the RR group samples, while the RG group is in an intermediate position between RR and GG groups. Sucrose and formate contributed greatly to the separation obtained by PCA, presenting a good correlation between the results. 1H NMR was an efficient technique to differentiate latex samples from different types of rootstocks and grafting and in the future could be used to predict rubber production by latex analysis.

Development of a BR-UASB-DHS system for natural rubber processing wastewater treatment.

Science.gov (United States)

Watari, Takahiro; Thanh, Nguyen Thi; Tsuruoka, Natsumi; Tanikawa, Daisuke; Kuroda, Kyohei; Huong, Nguyen Lan; Tan, Nguyen Minh; Hai, Huynh Trung; Hatamoto, Masashi; Syutsubo, Kazuaki; Fukuda, Masao; Yamaguchi, Takashi

2015-11-21

Natural rubber processing wastewater contains high concentrations of organic compounds, nitrogen, and other contaminants. In this study, a treatment system composed of a baffled reactor (BR), an upflow anaerobic sludge blanket (UASB) reactor, and a downflow hanging sponge (DHS) reactor was used to treat natural rubber processing wastewater in Vietnam. The BR showed good total suspended solids removal of 47.6%, as well as acidification of wastewater. The UASB reactor achieved a high chemical oxygen demand (COD) removal efficiency of 92.7% ± 2.3% and energy recovery in the form of methane with an organic loading rate of 12.2 ± 6.6 kg-COD·m -3 ·day -1 . The DHS reactor showed a high performance in residual organic matter removal from UASB effluent. In total, the system achieved high-level total COD removal of 98.6% ± 1.2% and total suspended solids removal of 98.0% ± 1.4%. Massive parallel 16S rRNA gene sequencing of the retained sludge in the UASB reactor showed the predominant microbial phyla to be Bacteroidetes, Firmicutes, Proteobacteria, WWE1, and Euryarchaeota. Uncultured bacteria belonging to the phylum Bacteroidetes and Phylum WWE1 were predominant in the UASB reactor. This microbial assemblage utilizes the organic compounds contained in natural rubber processing wastewater. In addition, the methane-producing archaea Methanosaeta sp. and Methanolinea sp. were detected.

Effects of Thermal and Humidity Aging on the Interfacial Adhesion of Polyketone Fiber Reinforced Natural Rubber Composites

OpenAIRE

Lee, Han Ki; Kim, Dae Sik; Won, Jong Sung; Jin, Da Young; Lee, Hyun Jae; Lee, Seung Goo

2016-01-01

Polyketone fiber is considered as a reinforcement of the mechanical rubber goods (MRG) such as tires, automobile hoses, and belts because of its high strength and modulus. In order to apply it to those purposes, the high adhesion of fiber/rubber interface and good sustainability to aging conditions are very important. In this study, polyketone fiber reinforced natural rubber composites were prepared and they were subjected to thermal and humidity aging, to assess the changes of the interfacia...

Proceedings of the international symposium on radiation vulcanization of natural rubber latex

International Nuclear Information System (INIS)

Machi, Sueo

1990-01-01

The First International Symposium on Radiation Vulcanization of Natural Rubber Latex (RVNRL) was held from 26 to 28 July 1989 at Tokyo and Takasaki. In these proceedings, thirty six papers presented at the Symposium are compiled. Main topics are commercial application of RVNRL, characterization of NR latex and vulcanization, properties of radiation vulcanized NR latex, development of sensitizers, mechanism of RVNRL, RVNRL with electron beams, and new Co-60 irradiator for RVNRL. Absence of nitrosamines and low cytotoxicity of radiation vulcanized NR latex are recognized as the remarkable advantages of RVNRL. The radiation vulcanization process for the production of protective rubber gloves for radioactive contamination was presented as the first commercial success in RVNRL. It was reported that various kinds of rubber articles for medical uses have being developed in West Germany. A sensitizer system consisting of n-butyl acrylate and t-butyl hydroperoxide was found to reduce the vulcanization dose to 8 kGy. (author)

Trial production of low protein irradiated natural rubber latex by low energy electron beam in pilot scale

International Nuclear Information System (INIS)

Utama, Marga; Yoshii, F.; Kume, T.

2006-01-01

Three importance factors for producing low protein by low energy electron beam (250 keV/10 mA) irradiation in pilot scale (20 liters per bath) with 1,9-nonediol diacrylate (NDA) namely: maturation time of natural rubber latex before irradiation, treatment of irradiated natural rubber latex (INRL) before and after centrifugation, and standard irradiation method has been carried out. The results showed that the optimum irradiation time for producing INRL with 5 phr (part hundred ratio of rubber) of NDA as sensitize agent, and with the rotation speed of agitation 210 rpm (rotation per minutes) was between 20-30 minutes. By using this condition tensile strength of the INRL film was 26 MPa. The maturation of natural rubber latex before irradiation is the key for driving the quality of INRL. Water extractable protein content of INRL after leaching in 1% ammonia solution for 30 minutes at room temperature was around 47 μ/g, and after adding with 1 phr of PVA (poly vinyl alcohol) or 0.1 phr CMC (carboxy methyl cellulose) the water extractable protein content decrease less than 6 μ/g. (author)

Sustainable shape memory polymers based on epoxidized natural rubber cured by zinc ferulate via oxa-Michael reaction

Directory of Open Access Journals (Sweden)

Xuhui Zhang

2015-10-01

Full Text Available Although various shape memory polymers (SMPs or diverse applications have been widely reported, the SMPs based on rubbers have been rarely realized due to the low triggering temperature of rubbers. In another aspect, the SMPs based on sustainable substances are highly desired for the growing shortage in fossil resources. In the present study, we accordingly developed the sustainable SMPs with tunable triggering temperature, based on natural rubber (NR and ferulic acid (FA as the raw materials. Specifically, the SMPs are based on a crosslinked network of epoxidized natural rubber (ENR crosslinked by in situ formed zinc ferulate (ZDF via oxa-Michael reaction. The excellent shape memory effect (SME is found in these SMPs, as evidenced by the high fixity/recovery ratio and the tunable triggering temperature. With the incorporation of natural halloysite nanotubes (HNTs, the stress and recovery rate of the SMPs are found to be tunable, which widens the application of this kind of SMPs. The combination of adoption of sustainable raw materials, and the excellent and tunable SME makes these SMPs potentially useful in many applications, such as various actuators and heat-shrinkable package materials.

Rubber molds for investment casting

International Nuclear Information System (INIS)

Sibtain, S.N.

2011-01-01

The main objective of the project is to investigate different types of molding rubbers used for investment casting. The level of shape complexity which can be achieved by using these rubber molds is also studied. It was almost impossible to make complex shapes molds using metal molds, in that cases rubber molds are very important because they arc flexible and give accurate and precise part dimensions. Turbine blades are hi-tech components with air-foil geometries that have close dimensional tolerances. They are made of super-alloys and manufactured by investment casting. The final blade profile depends upon the dimensional accuracy in each of the processing steps. In the present work experimental study for the production of high quality low cost castings of turbine blades using rubber molds and injected wax patterns is presented. Natural Rubber molds and wax patterns from these molds were made. Different types of molding rubbers were studied including natural rubber, silicone rubber and liquid silicone rubber. It was found that by using rubber molds we can make most complex shape with very less finishing required. The shrinkage was 12% as compared to original master pattern. Rubber molds were made using laboratory hot press. Three layers of rubber above and below the master pattern. After that vulcanization was done by giving temperature and pressure. (author)

African Journal of Biotechnology - Vol 8, No 25 (2009)

African Journals Online (AJOL)

An overview of the potentials of natural rubber (Hevea brasiliensis) engineering for the production of valuable proteins · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD ... A review of the use of prebiotic in aquaculture for fish and shrimp · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD ...

Effect of seasonal collection on callus Induction, proliferation and ...

African Journals Online (AJOL)

Hevea brasiliensis that is grown in Thailand and Southeast Asia is a very valuable source of natural rubber. However, few studies have been conducted to evaluate the effects of seasonal effect on plantlet regenera-tion through somatic embryogenesis from anther culture. Thus, this study discussed the effect of season on ...

Premilinary studies for optimiziing a protocol for obtaining embryogenic calluses in two rubber (Hevea brasiliensis Mull. Arg clones from different geographical origins Estudios preliminares en la estandarización de un protocolo para la obtención de callos embriogénicos en dos clones de caucho (Hevea brasiliensis Müll. Arg. de diferentes orígenes geográficos

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Medina S. Marisol

2006-07-01

Full Text Available The influence of growth regulators on obtaining friable rubber (Hevea brasiliensis Müll. Arg. calluses with no plant regeneration as investigated. Two clones having different geographical origin were used in all trails carried out in this study: FX 3864 (South-American and PB 254 (Asian. Young leaves and eight- to ten-week-old seed integument from both clones were used as explants in several experiments; they were initially cultured in MH medium (Carron, et ál., 1989, modified MH medium (Montoro, et ál., 1993, 2000 and modified MS medium (Carron, et at,. 1992, no positive response being obtained by days 25 or 50. However, other trials were carried out with the integument in modified MS medium (1962, 0.67 mg/L BAP and 0.66 mg/L 2-4 D being added as medium for initiating embryogenesis, the formation of white, friable calluses being observed by day 25 in the two selected clones. These calluses were sub-cultured in MS supplemented with 0.35 mg/L BAP and 0.2 mg/L 2-4 D as callogenesis expression medium, embryogenic expression being observed in both clones by day 50. Equally friable white calluses were obtained from young leaves in the two clones in MS medium supplemented with 1.0 mg/L BAP, 1.0 mg/L ANA but without IBA and kinetin by day 25. Calluses sub-cultured in the same medium supplemented with 0.5 mg/L BAP and 0.5 mg/L ANA began to show increased friability after 50 days. culture. This work is a partial report of a macro-project for optimising a protocol for rubber (Hevea brasiliensis  multiplication by somatic embryogenesis.Se investigó la influencia de los reguladores de crecimiento para la obtención de callos friables en caucho (Hevea brasiliensis Müll. Arg. sin llegar a obtenerse regeneración de plántulas. En todos los ensayos realizados en este estudio, se utilizaron dos clones de diferentes orígenes geográficos: el FX 3864 (suramericano y el PB 254 (asiático. Para los diferentes tratamientos se utilizaron como explantes hojas j

Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

Energy Technology Data Exchange (ETDEWEB)

Nazir, Khuzaimah; Aziz, Ahmad Fairoz [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Adam, Nurul Ilham [Faculty of Applied Sciences, Universiti Teknologi MARA, KampusTapah, 35400 Tapah Road, Tapah, Perak (Malaysia); Yahya, Muhd Zu Azhan [Faculty of Defence Sciences and Technology, Universiti Pertahanan Nasional Malaysia, Kem Sungai Besi, 57000 Kuala Lumpur (Malaysia); Ali, Ab Malik Marwan [Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

2015-08-28

Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance ({sup 1}HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in {sup 1}HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF{sub 3}SO{sub 3} show the highest conductivity. The complexation between EMG30 and LiCF{sub 3}SO{sub 3} were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR)

Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

International Nuclear Information System (INIS)

Nazir, Khuzaimah; Aziz, Ahmad Fairoz; Adam, Nurul Ilham; Yahya, Muhd Zu Azhan; Ali, Ab Malik Marwan

2015-01-01

Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance ( 1 HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in 1 HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF 3 SO 3 show the highest conductivity. The complexation between EMG30 and LiCF 3 SO 3 were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR)

Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

Science.gov (United States)

Nazir, Khuzaimah; Aziz, Ahmad Fairoz; Adam, Nurul Ilham; Yahya, Muhd Zu Azhan; Ali, Ab Malik Marwan

2015-08-01

Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance (1HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in 1HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF3SO3 show the highest conductivity. The complexation between EMG30 and LiCF3SO3 were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR).

The comparison of properties and cost of material use of natural rubber and sand in manufacturing cement mortar for construction sub-base layer

Science.gov (United States)

Rahman, R.; Nemmang, M. S.; Hazurina, Nor; Shahidan, S.; Khairul Tajuddin Jemain, Raden; Abdullah, M. E.; Hassan, M. F.

2017-11-01

The main issue related to this research was to examine the feasibility of natural rubber SMR 20 in the manufacturing of cement mortar for sub-base layer construction. Subbase layers have certain functions that need to be fulfilled in order to assure strong and adequate permeability of pavement performance. In a pavement structure, sub-base is below the base and serves as the foundation for the overall pavement structure, transmitting traffic loads to the sub-grade and providing drainage. Based on this research, the natural rubber, SMR 20 was with the percentages of 0%, 5%, 10% and 15% to mix with sand in the manufacture of the cement mortar. This research describes some of the properties and cost of the materials for the natural rubber and sand in cement mortar manufacturing by laboratory testing. Effects of the natural rubber replacement on mechanical properties of mortar were investigated by laboratory testing such as compressive strength test and density. This study obtained the 5% of natural rubber replaced in sand can achieved the strength of normal mortar after 7 days and 28 days. The strength of cement mortar depends on the density of cement mortar. According to the cost of both materials, sand shows the lower cost in material for the cement mortar manufacturing than the uses of natural rubber. Thus, the convectional cement mortar which used sand need lower cost than the modified rubber cement mortar and the most economical to apply in industrial. As conclusion, the percentage of 5% natural rubber in the cement mortar would have the same with normal cement mortar in terms of the strength. However, in terms of the cost of the construction, it will increase higher than cost of normal cement mortar production. So that, this modified cement mortar is not economical for the road sub-base construction.

Effects of radio sensitizers in the vulcanization of natural rubber latex induced by gamma radiation

International Nuclear Information System (INIS)

Souza, A. de; Canavel, V.; Araujo, S.C. de; Guedes, S.M.L.

1992-01-01

The effect of C Cl 4 and n-butyl acrylate as a sensitizer for radiation vulcanization of 60% DRC natural rubber latex with gamma rays, was studied relating tensile strength of vulcanized latex. The vulcanization dose is 200 kGy for natural rubber latex and it decreases to 40 kGy and to 9 kGy in the presence of C Cl 4 / potassium laureate and n-butyl acrylate / t-butyl hydroperoxide, respectively. The H 2 O 2 as a co-sensitizer does not change the efficiency of the combination of these sensitizers. The IV spectra show the formation of C=O after the irradiation as consequence of oxidation reactions. (author)

Effect of carbon black composition with sludge palm oil on the curing characteristic and mechanical properties of natural rubber/styrene butadiene rubber compound

Science.gov (United States)

Mohamed, R.; Nurazzi, N. Mohd; Huzaifah, M.

2017-07-01

This study was conducted to investigate the possibility of utilizing sludge palm oil (SPO) as processing oil, with various amount of carbon black as its reinforcing filler, and its effects on the curing characteristics and mechanical properties of natural rubber/styrene butadiene rubber (NR/SBR) compound. Rubber compound with fixed 15 pphr of SPO loading, and different carbon black loading from 20 to 50 pphr, was prepared using two roll mills. The cure characteristics and mechanical tests that have been conducted are the scorch and cure time analysis, tensile strength and tear strength. Scorch time (ts5) and cure time (t90) of the compound increases with the increasing carbon black loading. The mechanical properties of NR/SBR compound viz. the tensile strength, modulus at 300% strain and tear strength were also improved by the increasing carbon black loading.

Rubber mixing process and its relationship with bound rubber and crosslink density

Science.gov (United States)

Hasan, A.; Rochmadi; Sulistyo, H.; Honggokusumo, S.

2017-06-01

This research studied the relationship between bound rubber and crosslink density based on rubber mixing process. Bound rubber was obtained after natural rubber was masticated and mixed with rubber chemicals and filler while crosslink density was collected after rubber compound was vulcanized. Four methods are used and each method refers to four ways of incorporating carbon black during mixing. The first method, after rubber was masticated for 5 minutes, the addition of rubber chemicals and filler was done simultaneously. Rubber was masticated for 1 minute and continued mixing of rubber chemicals and filler where mixing was different from first method. This was the second method. The third method was the same as the second method but the filler used N 660 while in the second method N 330. The last method is not the same as the first and second, the rubber is only masticated for 3 minutes and then mixed with filler and followed by rubber chemicals sequentially. The results showed that bound rubber and crosslink density were influenced by mixing and mastication process. Bound rubber dropped and crosslink density was relatively stable in the first three mixing methods for increasing carbon black at the beginning of the mixing process. Bound rubber and crosslink density stated opposite results in the fourth mixing method. The higher the bound rubber the lower the crosslink density. Without regard to mixing methods, there is a non-linear relationship between bound rubber formation and crosslink density determination

Glyoxalase I expression pattern in Hevea brasiliensis seedlings ...

African Journals Online (AJOL)

sunny t

2016-03-16

Mar 16, 2016 ... developing tolerance to drought stress in Hevea brasiliensis. In the present study, a partial .... First strand cDNA was synthesized from total RNA by reverse transcription with oligo (dT) ..... Genetic engineering of the glyoxalase ...

Dinâmica populacional do parasitoide de ovos erythmelus tingitiphagus (hymenoptera: mymaridae em clone de seringueira, em Itiquira, MT Population dynamic of egg parasitoid erythmelus tingitiphagus (hymenoptera: mymaridae in rubber tree clone in Itiquira, Mato Grosso State, Brazil

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Rodrigo Souza Santos

2013-04-01

Full Text Available O percevejo-de-renda Leptopharsa heveae Drake & Poor (Hemiptera: Tingidae é uma das mais importantes pragas da heveicultura no Brasil, principalmente nas regiões Sudeste e Centro-Oeste. Devido ao seu hábito sugador, na face abaxial das folhas, esta praga leva à senescência precoce das mesmas e a reduções na produção de látex em até 30%. Dentre os inimigos naturais de L. heveae está o parasitoide de ovos Erythmelus tingitiphagus (Soares (Hymenoptera: Mymaridae, regulando suas populações em condições naturais. O objetivo deste estudo foi verificar a dinâmica populacional deste parasitoide, bem como correlacioná-la com os fatores meteorológicos temperatura e pluviosidade, em plantio comercial de seringueira do clone PB 217, em Itiquira, MT. Semanalmente foram coletadas quatro folhas maduras por árvore, no terço inferior da copa de 40 árvores, totalizando 160 folhas por amostragem, no período de agosto de 2006 a janeiro de 2007. Houve correlação positiva entre a dinâmica populacional e os fatores meteorológicos, sendo o pico populacional do parasitoide observado no mês de novembro e declinando até janeiro na área estudada.The lace bug Leptopharsa heveae Drake & Poor (Hemiptera: Tingidae is one of the most import heveiculture pests in Brazil, mainly in the southeast and central-west regions. Due to its sucking habit on the abaxial surface, this pest causes precocious senescence in leaves, and leads to the reduction in latex production in up to 30% of them. Among the natural enemies of L. heveae is the egg parasitoid Erythmelus tingitiphagus (Soares (Hymenoptera: Mymaridae, regulating populations of L. heveae in natural conditions. The objective of this work was to verify the population dynamics of this parasitoid, as well as to correlate it with meteorological factors such as temperature and rainfall, in a commercial plantation of rubber trees of the PB 217 clone, in Itiquira, in the Mato Grosso state, Brazil. Four

Extractable proteins from electron beam (EB) irradiated natural rubber (NR) latex

International Nuclear Information System (INIS)

Feroza Akhtar; Fumio Yoshii; Keizo Makuuchi

1996-01-01

The protein assay of natural rubber latex (NRL) vulcanized by low energy electron beam (EB, 300 keV, 30 mA) has been carried out using Bicinchoninic acid (BCA) reagent. Extractable protein in irradiated latex film was determined by measuring the absorption of colored solution at 562 nm using UV spectrometer. The effect of various radiation doses on the extractable protein content of NRL was investigated. It was ,found that the quantities of extractable protein increases with radiation dose. When compared with ,gamma-ray irradiated samples the same trend was observed. Electron beam irradiated latex films are leached in 1% (ammonia water for various lengths of time. From the results it was established that within 2 hours of leaching in ammonia water most of the extractable protein (96%) were removed from rubber film

Dicer-like Proteins Regulate the Growth, Conidiation, and Pathogenicity of Colletotrichum gloeosporioides from Hevea brasiliensis

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Qiannan Wang

2018-01-01

Full Text Available Colletotrichum gloeosporioides from Hevea brasiliensis is the hemibiotrophic fungi which could cause anthracnose in rubber trees. Dicer like proteins (DCL were the core enzymes for generation of small RNAs. In the present study, the knocking-out mutants of two dicer like proteins encoding genes of C. gloeosporioides were constructed; and functions of two proteins were investigated. The results showed that DCL play important roles in regulating the growth, conidiation and pathogenicity of C. gloeosporioides; and there is a functional redundancy between DCL1 and DCL2. Microscopy analysis and DAB staining revealed that loss of penetration ability into the host cells, instead of the decreased growth rate, was the main cause for the impaired pathogenicity of the ΔDcl1ΔDcl2 double mutant. Proteomics analysis suggested that DCL proteins affected the expression of functional proteins to regulating multiple biological processes of C. gloeosporioides. These data lead to a better understanding of the functions of DCL proteins in regulating the development and pathogenesis of C. gloeosporioides.

In situ reactive compatibilization of natural rubber/acrylic-bentonite composites via peroxide-induced vulcanization

International Nuclear Information System (INIS)

Fu, Lihua; Lei, Zhiwen; Xu, Chuanhui; Chen, Yukun

2016-01-01

To achieve good interfacial interaction between fillers and rubber matrix is always a hot topic in rubber reinforcing industry. In this paper, acid activated bentonite (Bt) was alkalified to be alkaline calcium-bentonite (ACBt), then acrylic acid (AA) was employed to modify ACBt to obtain acrylic-bentonite (ABt). The results of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) illustrated that acrylate groups were chemically boned onto the surface of Bt and the layer spacing of Bt was increased. During peroxide-induced vulcanization, in situ compatibilization of ABt was realized via the reaction between the unsaturated bonds of acrylate groups on the surface of Bt and the natural rubber (NR) chains. This resulted in an enhanced cross-linked network which contributed to the improved mechanical properties of NR/ABt composites. - Highlights: • Acrylate groups were chemically boned onto the surface of bentonite. • In situ compatibilization was realized via the reaction of acrylate group and NR. • ABt particles participated in forming the NR crosslink network. • A potential reinforcing material options for “white” rubber products.

In situ reactive compatibilization of natural rubber/acrylic-bentonite composites via peroxide-induced vulcanization

Energy Technology Data Exchange (ETDEWEB)

Fu, Lihua; Lei, Zhiwen [Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Xu, Chuanhui, E-mail: xuhuiyee@gxu.edu.cn [Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Chen, Yukun, E-mail: cyk@scut.edu.cn [The Key Laboratory of Polymer Processing Engineering, Ministry of Education, China(South China University of Technology), Guangzhou, 510640 (China)

2016-02-15

To achieve good interfacial interaction between fillers and rubber matrix is always a hot topic in rubber reinforcing industry. In this paper, acid activated bentonite (Bt) was alkalified to be alkaline calcium-bentonite (ACBt), then acrylic acid (AA) was employed to modify ACBt to obtain acrylic-bentonite (ABt). The results of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) illustrated that acrylate groups were chemically boned onto the surface of Bt and the layer spacing of Bt was increased. During peroxide-induced vulcanization, in situ compatibilization of ABt was realized via the reaction between the unsaturated bonds of acrylate groups on the surface of Bt and the natural rubber (NR) chains. This resulted in an enhanced cross-linked network which contributed to the improved mechanical properties of NR/ABt composites. - Highlights: • Acrylate groups were chemically boned onto the surface of bentonite. • In situ compatibilization was realized via the reaction of acrylate group and NR. • ABt particles participated in forming the NR crosslink network. • A potential reinforcing material options for “white” rubber products.

Cream concentrated latex for foam rubber products

Science.gov (United States)

Suksup, R.; Imkaew, C.; Smitthipong, W.

2017-12-01

Fresh natural latex (around 40% rubber and 60% water) can be transformed to concentrated natural latex (around 60% rubber and 40% water) in order to realise economical transportation and easier latex product’s preparation. The concentrated natural latex is an extremely valuable material. It can be applied for many types of products, for example, foam rubber as pillow and mattress, elastic band, etc. Industrially, the concentrated natural latex can be prepared by centrifugation which requires an enormous expensive machine. From the eco-friendly products point of view, most of rubber entrepreneurs in the world try to develop a green rubber product. So, the main objective of this study is to prepare the cream concentrated latex without any sophisticated machine. Thus, we work on a simple, cheap and green method that does not use any expensive machine but uses water-based chemical as sodium alginate to prepare the cream concentrated latex. The optimal amount of sodium alginate in the latex was studied. The main characteristics of the cream concentrated latex were tested by various technics, such as alkalinity, total solid content (TSC), dry rubber content (DRC), etc. We found that there are no significant differences of results between fresh natural latex and cream concentrated latex, except for the TSC and DRC. The TSC and DRC of cream latex are higher than those of fresh natural latex. Finally, we propose a model of natural rubber particle and sodium alginate to form the cream concentrated latex.

Self-Healing Natural Rubber with Tailorable Mechanical Properties Based on Ionic Supramolecular Hybrid Network.

Science.gov (United States)

Xu, Chuanhui; Cao, Liming; Huang, Xunhui; Chen, Yukun; Lin, Baofeng; Fu, Lihua

2017-08-30

In most cases, the strength of self-healing supramolecular rubber based on noncovalent bonds is in the order of KPa, which is a challenge for their further applications. Incorporation of conventional fillers can effectively enhance the strength of rubbers, but usually accompanied by a sacrifice of self-healing capability due to that the filler system is independent of the reversible supramolecular network. In the present work, in situ reaction of methacrylic acid (MAA) and excess zinc oxide (ZnO) was realized in natural rubber (NR). Ionic cross-links in NR matrix were obtained by limiting the covalent cross-linking of NR molecules and allowing the in situ polymerization of MAA/ZnO. Because of the natural affinity between Zn 2+ ion-rich domains and ZnO, the residual nano ZnO participated in formation of a reversible ionic supramolecular hybrid network, thus having little obstructions on the reconstruction of ionic cross-links. Meanwhile, the well dispersed residual ZnO could tailor the mechanical properties of NR by changing the MAA/ZnO molar ratios. The present study thus provides a simple method to fabricate a new self-healing NR with tailorable mechanical properties that may have more potential applications.

Water absorption and mechanical properties of water-swellable natural rubber

Directory of Open Access Journals (Sweden)

Diew Saijun

2009-11-01

Full Text Available Water-swellable rubber (WSR was prepared by blending superabsorbent polymer (SAP of crosslinked poly(acrylamide-co-sodium acrylate with natural rubber in latex condition. The crosslinked poly(acrylamide-co-sodium acrylate was first prepared by inverse suspension polymerization from acrylamide and sodium acrylate monomers with potassiumpersulfate initiator and N,N-methylenebisacrylamide crosslinker. The reaction was carried out at 60oC for 40 mins. Water absorption properties, such as the degree of water absorption, water absorption rate, degree of weight loss, and mechanicalproperties of WSR were then investigated. It was found that the degree of water absorption, water absorption rate, and thedegree of weight loss increased, while tensile strength and elongation at break decreased with increasing quantity of SAP inthe blends. However, the degree of water absorption, degree of weight loss, and elongation at break decreased, but tensilestrength increased with increasing quantity of the N-tert-butyl-2-benzothiazyl sulphenamide (TBBS accelerator used in thecompounds formulation.

Flutuação populacional e sintomas de dano por ácaros (Acari em seringueira no Estado do Mato Grosso, Brasil Population fluctuation and mite (Acari damage symptoms in rubber trees in the State of Mato Grosso, Brazil

Directory of Open Access Journals (Sweden)

Noeli Juarez Ferla

2008-04-01

Full Text Available Apesar da grande importância da cultura da seringueira (Hevea brasiliensis Muell. Arg. para o Brasil, pouco se conhece sobre a flutuação populacional dos ácaros nessa cultura. O objetivo deste trabalho foi estudar a flutuação populacional de ácaros na seringueira no Estado do Mato Grosso, bem como observar a evolução dos sintomas de ataque de tais pragas nessa planta. O estudo foi conduzido em campos de seringueira de Itiquira e Pontes e Lacerda, Estado do Mato Grosso, com seis clones: FX 3864, RRIM 600, IAN 873, IAN 713, PB 260 e PR 255, cujas coletas foram realizadas de agosto de 1998 a julho de 2000. Na safra de 1998/1999, a amostragem foi de 150 folhas de cada um dos estratos basal, mediano e apical, em 10 plantas ao acaso. A metodologia de coleta na safra de 1999/2000 foi alterada devido aos resultados da parcial anterior de cinco folhas do estrato mediano de cada uma das 15 plantas ao acaso. Calacarus heveae Feres foi a espécie mais freqüente em Itiquira e Phyllocoptruta serigueirae Feres em Pontes e Lacerda. A queda prematura das folhas foi observada apenas em Itiquira.Despite the importance of rubber trees (Hevea brasiliensis Muell. Arg. to Brazil, little is known about mite population fluctuation on this crop. The aim of this work was to study the fluctuation of the mite population on rubber trees in the state of Mato Grosso and to observe the evolution of the symptoms caused by their attack. This study was conducted in rubber tree fields at Itiquira and Pontes e Lacerda in the state of Mato Grosso with six clones: FX 3864, RRIM 600, IAN 873, IAN 713, PB 260 and PR 255. Samplings were conducted between August 1998 and July 2000. The 1998/1999 samples consisted of 150 leaves of each of the basal, median and apical strata of 10 plants, randomly taken. The 1999/2000 sampling methodology was changed due the results for the previous partial for five leaves of the median stratum of each of 15 plants randomly taken. Calacarus heveae

Study of the effect of ionizing radiation on the structure of natural rubber latex by positron annihilation technique

International Nuclear Information System (INIS)

Lopez Saldana, I.R.

1993-01-01

At the present research, were studied the changes in natural rubber latex structure, due to electron beam by a 3 MeV, 25 m A Dynamitron electron accelerator. The natural rubber latex was irradiated at 30, 40 and 50 kGy/s dose rate, over a total dose range from 150 to 250 kGy, for each dose rate used. From natural rubber latex irradiated films were prepared by casting with 0.7 mm. thickness. In the main part, the study was made by positron annihilation lifetime (PAL), this technique is unique in the determination of free-volume properties due to the fact that positronium atom (Ps) is found to be preferentially localized in the free-volume region of polymeric materials. The positron lifetime measurements were performing using a gamma-gamma coincidence system. These results were analyzed by PATFIT-88 program computer into three components, the long-lived component for orthopositronium (o-Ps) with parameters lifetime (τ 3 ) and formation intensity (I 3 ), were plotted and analyzed for each dose rate and total dose used. Besides with τ 3 were calculated the mean free-volume size based on the spherical model for the free-volume bubble, found that the free-volume decrease slightly with the total dose due to the crosslinking of natural rubber latex. Besides was studied the effect of dose rate on tensile strength, the tensile strength is increased with the total dose although there was not a clear effect due to the dose rate. Also the films were subjected to aging in order to determined the thermal stability of natural rubber latex irradiated, the results show that the films have good stability. Besides was used the infrared spectroscopy to determine the changes due to the crosslinking by variations in the characteristically absorption bands for cis 1,4-polyisoprene. (Author)

Análise econométrica da demanda brasileira de importação de borracha natural, de 1964 a 2005 Econometric analysis of Brazilian import demand for natural rubber during 1964-2005

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Naisy Silva Soares

2008-12-01

Full Text Available Este trabalho teve por objetivos especificar e estimar a demanda brasileira de importação de borracha natural, no período de 1964 a 2005. As variáveis explicativas do modelo de demanda de importação foram: preço de importação da borracha natural, PIB per capita, taxa de câmbio, taxa de juros, quantidade de borracha natural produzida internamente e tendência. As estimativas obtidas utilizando o modelo de ajustamento parcial confirmaram que as variáveis explicativas afetam, significativamente, a demanda brasileira de importação de borracha natural. Os resultados apontaram que a demanda brasileira de importação de borracha natural é inelástica com relação ao preço de importação e à renda; é pouco sensível a variações no preço de importação, à taxa de câmbio, à renda e à taxa de juros, mas é sensível às variações na quantidade de borracha natural produzida internamente, no curto e longo prazos; e a borracha natural é um bem normal.This work aimed to specify and estimate the Brazilian import demand for natural rubber from 1964 to 2005. The variables applied to explain import demand were: natural rubber import price, GNP per capita, exchange nominal rate (R$/US$, "overnight" interest rate, natural rubber domestic production and trend. The estimates showed that the variables significantly affected the Brazilian import demand for natural rubber. The results indicated that the Brazilian import demand for natural rubber is inelastic in relation to import price and income; little sensitive to variations in import price, exchange nominal rate (R$/US$, income and "overnight" interest rate but it is sensitive to domestic rubber production variations , in the short and long runs; and that natural rubber is a regular commodity.

Whole-transcriptome survey of the putative ATP-binding cassette (ABC) transporter family genes in the latex-producing laticifers of Hevea brasiliensis.

Science.gov (United States)

Zhiyi, Nie; Guijuan, Kang; Yu, Li; Longjun, Dai; Rizhong, Zeng

2015-01-01

The ATP-binding cassette (ABC) proteins or transporters constitute a large protein family in plants and are involved in many different cellular functions and processes, including solute transportation, channel regulation and molecular switches, etc. Through transcriptome sequencing, a transcriptome-wide survey and expression analysis of the ABC protein genes were carried out using the laticiferous latex from Hevea brasiliensis (rubber tree). A total of 46 putative ABC family proteins were identified in the H. brasiliensis latex. These consisted of 12 'full-size', 21 'half-size' and 13 other putative ABC proteins, and all of them showed strong conservation with their Arabidopsis thaliana counterparts. This study indicated that all eight plant ABC protein paralog subfamilies were identified in the H. brasiliensis latex, of which ABCB, ABCG and ABCI were the most abundant. Real-time quantitative reverse transcription-polymerase chain reaction assays demonstrated that gene expression of several latex ABC proteins was regulated by ethylene, jasmonic acid or bark tapping (a wound stress) stimulation, and that HbABCB15, HbABCB19, HbABCD1 and HbABCG21 responded most significantly of all to the abiotic stresses. The identification and expression analysis of the latex ABC family proteins could facilitate further investigation into their physiological involvement in latex metabolism and rubber biosynthesis by H. brasiliensis.

Graft Copolymerization of Methyl Methacrylate Monomer onto Starch and Natural Rubber Latex Initiated by Gamma Irradiation

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S. Iskandar

2011-04-01

Full Text Available To obtain the degradable plastic, the graft copolymerization of methyl methacrylate onto starch and natural rubber latex was conducted by a simultaneous irradiation technique. Gamma-ray from cobalt-60 source was used as the initiator. The grafted copolymer of starch-polymethyl methacrylate and the grafted copolymer of natural rubber-polymethyl methacrylate were mixed in the blender, and dried it in the oven. The dried grafted copolymer mixture was then molded using hydraulic press machine. The effect of irradiation dose, composition of the grafted copolymer mixture, film forming condition and recycle effect was evaluated. The parameters observed were tensile strength, gel fraction and soil burial degradability of grafted copolymer mixture. It was found that the tensile strength of grafted copolymer mixture increased by -ray irradiation. Increasing of the grafted copolymer of natural rubber-polymethyl methacrylate content, the gel fraction and tensile strength of the grafted copolymer mixture increased. The tensile strength of the grafted copolymer mixture was increased from 18 MPa to 23 MPa after recycled (film forming reprocessed 3 times. The grafted copolymer mixture was degraded completely after soil buried for 6 months

The role of natural rubber in seismic isolation - a perspective

International Nuclear Information System (INIS)

Coveney, V.A.

1991-01-01

The ''base-isolation'' technique for protecting buildings against earthquakes is based on the fundamental physics of systems in oscillation. It relies on lowering the natural frequency of the building/support system below that of the major frequencies present in the earthquake. Although simple in concept, many years of development have been required to convert it into a practical, reliable system. Seen fifteen years ago as an eccentric dream, base isolation is today recognized as the only feasible method of protecting some buildings and their contents, and as an attractive option for a widening range of other types. In most practical systems, natural rubber has an essential role. (orig.) [de

Effect of Ingredient Loading on Surface Migration Kinetics of Additives in Vulcanized Natural Rubber Compounds

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Bryan B. Pajarito

2014-12-01

Full Text Available Surface migration kinetics of chemical additives in vulcanized natural rubber compounds were studied as function of ingredient loading. Rubber sheets were compounded according to a 212-8 fractional factorial design of experiment, where ingredients were treated as factors varied at two levels of loading. Amount of migrated additives in surface of rubber sheets was monitored through time at ambient conditions. The maximum amount and estimated rate of additive migration were determined from weight loss kinetic curves. Attenuated total reflection–Fourier transform infrared (ATR-FTIR spectroscopy and optical microscopy were used to characterize the chemical structure and surface morphology of sheet specimens during additive migration. ANOVA results showed that increased loading of reclaimed rubber, CaCO3, and paraffin wax signif icantly decreased the maximum amount of additive migration; by contrast, increased loading of used oil, asphalt, and mercaptobenzothiazole disulphide (MBTS increased the maximum amount. Increased loading of sulfur, diphenylguanidine (DPG, and paraffin wax significantly decreased the additive migration rate; increased loading of used oil, asphalt, and stearic acid elicited an opposite effect. Comparison of ATRFTIR spectra of migrated and cleaned rubber surfaces showed signif icant variation in intensity of specif ic absorbance bands that are also present in infrared spectra of migrating chemicals. Paraffin wax, used oil, stearic acid, MBTS, asphalt, and zinc stearate were identified to bloom and bleed in the rubber sheets. Optical micrographs of migrated rubber surfaces revealed formation of white precipitates due to blooming and of semi-transparent wet patches due to bleeding.

Effects of Thermal and Humidity Aging on the Interfacial Adhesion of Polyketone Fiber Reinforced Natural Rubber Composites

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Han Ki Lee

2016-01-01

Full Text Available Polyketone fiber is considered as a reinforcement of the mechanical rubber goods (MRG such as tires, automobile hoses, and belts because of its high strength and modulus. In order to apply it to those purposes, the high adhesion of fiber/rubber interface and good sustainability to aging conditions are very important. In this study, polyketone fiber reinforced natural rubber composites were prepared and they were subjected to thermal and humidity aging, to assess the changes of the interfacial adhesion and material properties. Also, the effect of adhesive primer treatment, based on the resorcinol formaldehyde resin and latex (RFL, of polyketone fiber for high interfacial adhesion was evaluated. Morphological and property changes of the rubber composites were analyzed by using various instrumental analyses. As a result, the rubber composite was aged largely by thermal aging at high temperature rather than humidity aging condition. Interfacial adhesion of the polyketone/NR composites was improved by the primer treatment and its effect was maintained in aging conditions.

Glyoxalase I expression pattern in Hevea brasiliensis seedlings ...

African Journals Online (AJOL)

Glyoxalase I expression pattern in Hevea brasiliensis seedlings under varied stress conditions. MVP Siraj, A Thulaseedharan, Anu Augustine. Abstract. Drought is one of the most important stress factors which adversely affect plants' growth and productivity. Global climate change may make this situation more serious in the ...

Thermomechanical analysis of Natural Rubber behaviour stressed at room temperature.

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Chrysochoos A.

2010-06-01

Full Text Available Owing to their high molecular mobility, stressed rubber chains can easily change their conformations and get orientated. This phenomena leads to so high reversible draw ratio that this behaviour is called rubber elasticity [1-3]. The analogy with ideal gases leads to an internal energy independent of elongation, the stress being attributed to a so-called configuration entropy. However, this analysis cannot take thermal expansion into account and moreover prohibits predicting standard thermo-elastic effect noticed at small elongations and the thermoelastic inversion effects [4]. This paper aims at : observing and quantifying dissipative and coupling effects associated with deformation energy, generated when Natural Rubber is stretched. re-examine the thermomechanical behaviour model of rubberlike materials, under the generalised standard material concept. From an experimental viewpoint, energy balance is created using infrared and quantitative imaging techniques. Digital Image Correlation (DIC provides in-the-plane displacement fields and, after derivation, strain and strain-rate fields. We have used those techniques to evidence the thermoelastic inversion effect as shown on Figure 1 where different weights have been fixed to warmed specimen and we monitored the sample deformation while it recovers room temperature. But we have also used those techniques to perform energy balance : analysis of the mechanical equilibrium allows estimates of the stress pattern and computation of deformation energy rates under a plane stress hypothesis [5]. Infrared Thermography (IRT gives the surface temperature of the sample. To estimate the distribution of heat sources, image processing with a local heat equation and a minimal set of approximation functions (image filtering was used. The time courses of deformation energy and heat associated with cyclic process are plotted in Figure 2. The time derivatives of both forms of energy are approximately similar. This

Solubility Study of Curatives in Various Rubbers

NARCIS (Netherlands)

Guo, R.; Talma, Auke; Datta, Rabin; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

2008-01-01

The previous works on solubility of curatives in rubbers were mainly carried out in natural rubber. Not too much information available on dissimilar rubbers and this is important because most of the compounds today are blends of dissimilar rubbers. Although solubility can be expected to certain

Epoxidized Natural Rubber/Chitosan Network Binder for Silicon Anode in Lithium-Ion Battery.

Science.gov (United States)

Lee, Sang Ha; Lee, Jeong Hun; Nam, Dong Ho; Cho, Misuk; Kim, Jaehoon; Chanthad, Chalathorn; Lee, Youngkwan

2018-05-16

Polymeric binder is extremely important for Si-based anode in lithium-ion batteries due to large volume variation during charging/discharging process. Here, natural rubber-incorporated chitosan networks were designed as a binder material to obtain both adhesion and elasticity. Chitosan could strongly anchor Si particles through hydrogen bonding, while the natural rubber could stretch reversibly during the volume variation of Si particles, resulting in high cyclic performance. The prepared electrode exhibited the specific capacities of 1350 mAh/g after 1600 cycles at the current density of 8 A/g and 2310 mAh/g after 500 cycles at the current density of 1 A/g. Furthermore, the cycle test with limiting lithiation capacity was conducted to study the optimal binder properties at varying degree of the volume expansion of silicon, and it was found that the elastic property of binder material was strongly required when the large volume expansion of Si occurred.

Synergistic effect of plasma-modified halloysite nanotubes and carbon black in natural rubber-butadiene rubber blend

NARCIS (Netherlands)

Poikelispaa, Minna; Das, Amit; Dierkes, Wilma K.; Vuorinen, Jyrki

2013-01-01

Halloysite nanotubes (HNTs) were investigated concerning their suitability for rubber reinforcement. As they have geometrical similarity with carbon nanotubes, they were expected to impart a significant reinforcement effect on the rubber compounds but the dispersion of the nanofillers is difficult.

Morphological Study on Room-Temperature-Cured PMMA-Grafted Natural Rubber-Toughened Epoxy/Layered Silicate Nanocomposite

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N. Y. Yuhana

2012-01-01

Full Text Available A morphological study was conducted on ternary systems containing epoxy, PMMA-grafted natural rubber, and organic chemically modified montmorillonite (Cloisite 30B. Optical microscopy, transmission electron microscopy (TEM, scanning electron microscopy (SEM, energy dispersive X-ray (EDX, and wide-angle X-ray diffraction (WAXD analysis were used. The following four materials were prepared at room temperature: cured unmodified epoxy, cured toughened epoxy, cured unmodified epoxy/Cloisite 30B nanocomposites, and cured toughened epoxy/Cloisite 30B nanocomposites. Mixing process was performed by mechanical stirring. Poly(etheramine was used as the curing agent. The detailed TEM images revealed co-continuous and dispersed spherical rubber in the epoxy-rubber blend, suggesting a new proposed mechanism of phase separation. High-magnification TEM analysis showed good interactions between rubber and Cloisite 30B in the ternary system. Also, it was found that rubber particles could enhance the separation of silicates layers. Both XRD and TEM analyses confirmed that the intercalation of Cloisite 30B was achieved. No distinct exfoliated silicates were observed by TEM. Aggregates of layered silicates (tactoids were observed by SEM and EDX, in addition to TEM at low magnification. EDX analysis confirmed the presence of organic and inorganic elements in the binary and ternary epoxy systems containing Cloisite 30B.

Estudio Preliminar del Género Hevea en Colombia

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Evans Schultes Richard

1946-04-01

Full Text Available Aunque en el territorio colombiano se han venido explotando los árboles caucheros del género Hevea durante casi medio siglo, solo ha sido en los últimos años cuando los botánicos han podido estudiar científicamente las especies en este país. En el presente artículo me limito a exponer de manera suscinta la identificación específica y la distribución geográfica del género Hevea en Colombia, valiéndome de las identificaciones botánicas preliminares que se han hecho hasta ahora, así como de los datos que he recogido personalmente y las informaciones que me han sido suministradas en fuentes fidedignas. Es de lamentarse la falta de exploración botánica en la hoya del río Inírida y sus afluentes que por ser, junto con el Guaviare, la región situada más al noreste de la zona de extensión del género Hevea, deja una laguna en los conocimientos que actualmente poseemos sobre la distribución geográfica de este género botánico. Igualmente carecemos de datos botánicos respecto de los ríos de menor importancia tales como el Yarí, el Cahuinarí y el Cotuhé, aunque sí los tenemos de las regiones mencionadas, lo mismo de otras vastas extensiones de la Amazonía Colombiana, podremos completar a satisfacción el estudio cuyo esbozo provisional presento en este trabajo.

Rubber

Science.gov (United States)

Graves, D. F.

The word "rubber" immediately brings to mind materials that are highly flexible and will snap back to their original shape after being stretched. In this chapter a variety of materials are discussed that possess this odd characteristics. There will also be a discussion on the mechanism of this "elastic retractive force." Originally, rubber meant the gum collected from a tree growing in Brazil. The term "rubber" was coined for this material by the English chemist Joseph Priestley, who noted that it was effective for removing pencil marks from paper. Today, in addition to Priestley's natural product, many synthetic materials are made that possess these characteristics and many other properties. The common features of these materials are that they are made up of long-chain molecules that are amorphous (not crystalline), and the chains are above their glass transition temperature at room temperature.

Effect of synthesized zinc stearate on the properties of natural rubber vulcanizates in the absence and presence of some fillers

International Nuclear Information System (INIS)

Helaly, F.M.; El Sabbagh, S.H.; El Kinawy, O.S.; El Sawy, S.M.

2011-01-01

Research highlights: → The mechanical properties of NR were enhanced through partial and complete replacement of zinc stearate. → The effect of adding different concentrations of zinc stearate on the physic-mechanical and SEM properties has been investigated. → Zinc stearate was found to play dual role, it reinforces the matrix blow its melting point and higher temperature it plasticizers the system. → Zinc stearate can be used as activator for sulfur vulcanization process of rubber instead of ZnO and stearic acid; in absence and presence of fillers. -- Abstract: Zinc stearate was synthesized by precipitation method through two steps; neutralization of stearic acid by sodium hydroxide then double decomposition using zinc sulphate to precipitate zinc stearate. Mass balances of the two steps were calculated and the physical properties of the prepared zinc stearate were measured and compared to standard. It was characterized and incorporated it into natural rubber in the absence and presence of some filler through mixing process of rubber. The vulcanization process was carried out at 142 o C. The rheological properties of natural rubber mixes were measured using oscillating disc rheometer. The plysico-mechanical properties of the vulcanizates were determined using tensile testing machine. It was found that, partial and complete replacement of synthesized zinc stearate instead of the conventional zinc oxide and stearic acid; enhanced the physico-mechanical properties of natural rubber. The measured reinforcing parameter value α f can be arranged according to the type of filler as follows: HAF>Hisil>CaCO 3 >Ca 3 (PO 4 ) 2 >BaSO 4 >Talc The highest value of α f represents the strength of filler and consequently the reinforcing effect of carbon black (HAF) filler while the lowest value of α f was observed for Talc which show moderate reinforcing effect of Talc. The scanning electron microscope study showed high surface homogenity and good dispersion of zinc

Enhancing the thermal stability of natural rubber/recycled ethylene–propylene–diene rubber blends by means of introducing pre-vulcanised ethylene–propylene–diene rubber and electron beam irradiation

International Nuclear Information System (INIS)

Nabil, H.; Ismail, H.

2014-01-01

Highlights: • New route of processing was introduced to optimise the thermal stability of NR/R-EPDM blends. • Pre-vulcanised EPDM and EB irradiation were introduced into NR/R-EPDM blends. • Thermal stability is obviously enhanced by applying these two techniques. • Applying new route of processing methods is clearly successful to NR/R-EPDM blends. - Abstract: Most rubber materials are subjected to oxidation. The rate of oxidation depends on the type of rubber, processing method, and end-use conditions. The oxidation of rubber can result in the loss of physical properties, such as tensile strength, elongation, and flexibility. Hence, the service life is determined by oxidation stability. Thermal properties are relevant to the potential use of polymeric materials in many consumer oriented applications. Thermo-oxidative ageing and thermogravimetric analysis (TGA) have been proven to be successful techniques in determining the thermal stability of polymers and polymer blends. In this article, preparation of a series of natural rubber/recycled ethylene–propylene–diene rubber (NR/R-EPDM) blends is described. Processing of the blends, by means of introducing pre-vulcanised EPDM and electron beam (EB) irradiation, was carried out. Two thermal analysis methods, namely thermo-oxidative ageing and thermogravimetric analysis, were conducted. The results indicated that pre-vulcanising EPDM for 1.45 min (ts − 2) is sufficient to gain the optimum retained tensile and elongation at break. It was simultaneously observed that the introduction of pre-vulcanised EPDM increased decomposition temperature and activation energy by showing optimum values at a pre-vulcanising time of 3.45 min (ts). In the latter study, the retained properties increased after EB irradiation. The results can be verified by the thermal decomposition temperature and their activation energy. The obtained TG profiles and the calculated kinetic parameters indicated that introducing EB irradiation

Curing kinetics and mechanical behavior of natural rubber reinforced with pretreated carbon nanotubes

International Nuclear Information System (INIS)

Sui, G.; Zhong, W.H.; Yang, X.P.; Yu, Y.H.

2008-01-01

To significantly improve the performance of rubber materials, fundamental studies on rubber nanocomposites are necessary. The curing kinetics and vulcanizate properties of carbon nanotubes (CNTs)/natural rubber (NR) nanocomposites were analyzed in this paper. The pretreatment of CNTs was carried out by acid bath followed by ball milling with HRH bonding systems in experiments. The CNT/NR nanocomposites were prepared through solvent mixing on the basis of pretreatment of CNTs. The surface characteristic of CNTs and physical interaction between CNTs and NR macromolecules were analyzed by Fourier transform infrared spectroscopy (FT-IR). The vulcanization kinetics of CNT/NR nanocomposites were studied contrasting with the neat NR. The quality of the NR vulcanizates was assessed through static and dynamic mechanical property tests and scanning electron microscope (SEM). Curing kinetic parameters of the neat NR and CNT/NR nanocomposites were obtained from experiments; the results indicated that the presence of CNTs affects the curing process of the NR, and additional heating is required to cure CNT/NR nanocomposites due to its higher active energy. The dispersion of pretreated CNTs in the rubber matrix and interfacial adhesion between them were obviously improved. The physical and mechanical properties of the CNT/NR nanocomposites showed considerable increases by incorporation of the pretreated CNTs compared to the neat NR and untreated CNTs-filled NR nanocomposites

Curing kinetics and mechanical behavior of natural rubber reinforced with pretreated carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Sui, G. [Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Department of Mechanical Engineering and Applied Mechanics, North Dakota State University, Fargo, ND 58105 (United States); Zhong, W.H. [Department of Mechanical Engineering and Applied Mechanics, North Dakota State University, Fargo, ND 58105 (United States)], E-mail: Katie.Zhong@ndsu.edu; Yang, X.P.; Yu, Y.H. [Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029 (China)

2008-06-25

To significantly improve the performance of rubber materials, fundamental studies on rubber nanocomposites are necessary. The curing kinetics and vulcanizate properties of carbon nanotubes (CNTs)/natural rubber (NR) nanocomposites were analyzed in this paper. The pretreatment of CNTs was carried out by acid bath followed by ball milling with HRH bonding systems in experiments. The CNT/NR nanocomposites were prepared through solvent mixing on the basis of pretreatment of CNTs. The surface characteristic of CNTs and physical interaction between CNTs and NR macromolecules were analyzed by Fourier transform infrared spectroscopy (FT-IR). The vulcanization kinetics of CNT/NR nanocomposites were studied contrasting with the neat NR. The quality of the NR vulcanizates was assessed through static and dynamic mechanical property tests and scanning electron microscope (SEM). Curing kinetic parameters of the neat NR and CNT/NR nanocomposites were obtained from experiments; the results indicated that the presence of CNTs affects the curing process of the NR, and additional heating is required to cure CNT/NR nanocomposites due to its higher active energy. The dispersion of pretreated CNTs in the rubber matrix and interfacial adhesion between them were obviously improved. The physical and mechanical properties of the CNT/NR nanocomposites showed considerable increases by incorporation of the pretreated CNTs compared to the neat NR and untreated CNTs-filled NR nanocomposites.

Impact of the timing and duration of weed control on the establishment of a rubber tree plantation.

Science.gov (United States)

Guzzo, Caio D; Carvalho, Leonardo B de; Giancotti, Paulo R F; Alves, Pedro L C A; Gonçalves, Elaine C P; Martins, José V F

2014-03-01

Rubber tree production is reduced by weeds that compete for environmental resources; therefore, the timing and duration of weed control influences weed interference. The objectives of this study were to evaluate the growth of rubber tree (Hevea brasiliensis) plants, to determine the critical period for weed control, and to evaluate the growth recovery of rubber trees that coexisted with weeds for different periods of time after planting. Two groups of treatments were established under field conditions in the first year of the investigation: one group contained crescent periods of weed infestation, while the other contained crescent periods of weed control, also including a weed-free check and a total weedy check. In the second year of the investigation, the weeds were totally controlled. Urochloa decumbens was the dominant weed (over 90% groundcover). Crop growth was greatly reduced due to the weed interference. Plant height decreased more rapidly than did any other characteristic. Plant height, leaf dry mass, and leaf area decreased by 99%, 97% and 96%, respectively, and were the most reduced characteristics. Plant height also recovered more rapidly than did any characteristic when the period of weed control was lengthened. However, stem dry mass increased by 750%, making it the most recovered characteristic. The critical period for weed control was between 4 and 9½ months after planting in the first year; however, the rubber trees showed an expressive growth recovery when the weeds were controlled throughout the second year.

Study of tribological properties of natural rubber containing carbon nanotubes and carbon black as hybrid fillers

Science.gov (United States)

Harea, Evghenii; Stoček, Radek; Storozhuk, Liudmyla; Sementsov, Yurii; Kartel, Nikolai

2018-04-01

Dry friction and wear properties of natural rubber (NR), containing multi-walled carbon nanotubes (MWCNT) and carbon black (CB), were investigated. Natural rubber (NR)-based composites containing all common additives and curatives, and a fixed amount (30 phr—parts per 100 rubber by weight) of hybrid fillers (MWCNT x + CB30-x ) were prepared by simple mixing procedure and tested. The main goal was to study the behaviours of composites at different tribological testing conditions, such as friction speed and normal load. It was found that with an increase of concentration of MWCNT from x = 0 phr to x = 5 phr in studied composites, there was a decrease in the coefficient of friction (COF) with no significant change in wear in the framework of each used combination of testing parameters. Generally, higher friction speed at certain normal force led to the increase of COF of all the samples and wear reflected deliberate value fluctuation. Also, it was established that considerable growth of wear and unexpected reducing of friction coefficient ensued from increasing of applied load for every fixed sliding speed.

Radiation prevulcanized natural rubber latex: Cytotoxicity and safety evaluation on animal

Energy Technology Data Exchange (ETDEWEB)

Keong, C C; Zin, W M Wan; Ibrahim, P; Ibrahim, S, E-mail: chai@nuclearmalaysia.gov.my [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

2010-05-15

Radiation prevulcanized natural rubber latex (RVNRL) was claimed to be more user friendly than natural rubber latex prevulcanized by sulphur curing system. The absence of Type IV allergy inducing chemicals in RVNRL make it a suitable material for manufacturing of many kinds of latex products, especially those come into direct contact with users. This paper reveals and discusses the findings of cytotoxicity test and safety evaluation on animal for RVNRL. The test was done on RVNRL films prepared by coagulant dipping method and RVNRL dipped products produced by latex dipped product manufacturers. Cytotocixity test was carried out on mammalian cell culture American Type Culture Collection CCL 81, Vero. Results indicated that no cytotoxic effect from RVNRL films and products was found on the cell culture. Two animal studies, namely dermal sensitization study and primary skin irritation study, were done on gloves made from RVNRL. Albino white guinea pigs were used as test subjects in dermal sensitization study and results showed no sensitization induced by the application of test material in the guinea pigs. Primary skin irritation study was done on New Zealand white rabbits and results showed that the product tested was not corrosive and was not a primary irritant

Radiation prevulcanized natural rubber latex: Cytotoxicity and safety evaluation on animal

International Nuclear Information System (INIS)

Keong, C C; Zin, W M Wan; Ibrahim, P; Ibrahim, S

2010-01-01

Radiation prevulcanized natural rubber latex (RVNRL) was claimed to be more user friendly than natural rubber latex prevulcanized by sulphur curing system. The absence of Type IV allergy inducing chemicals in RVNRL make it a suitable material for manufacturing of many kinds of latex products, especially those come into direct contact with users. This paper reveals and discusses the findings of cytotoxicity test and safety evaluation on animal for RVNRL. The test was done on RVNRL films prepared by coagulant dipping method and RVNRL dipped products produced by latex dipped product manufacturers. Cytotocixity test was carried out on mammalian cell culture American Type Culture Collection CCL 81, Vero. Results indicated that no cytotoxic effect from RVNRL films and products was found on the cell culture. Two animal studies, namely dermal sensitization study and primary skin irritation study, were done on gloves made from RVNRL. Albino white guinea pigs were used as test subjects in dermal sensitization study and results showed no sensitization induced by the application of test material in the guinea pigs. Primary skin irritation study was done on New Zealand white rabbits and results showed that the product tested was not corrosive and was not a primary irritant

Silver nanoparticles delivery system based on natural rubber latex membranes

Energy Technology Data Exchange (ETDEWEB)

Guidelli, Eder Jose, E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo/FFCLRP-DF (Brazil); Kinoshita, Angela [Universidade do Sagrado Coracao (Brazil); Ramos, Ana Paula [Universidade de Sao Paulo/FFCLRP-DQ (Brazil); Baffa, Oswaldo [Universidade de Sao Paulo/FFCLRP-DF (Brazil)

2013-04-15

The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV-Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane ({approx}0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are

Silver nanoparticles delivery system based on natural rubber latex membranes

International Nuclear Information System (INIS)

Guidelli, Éder José; Kinoshita, Angela; Ramos, Ana Paula; Baffa, Oswaldo

2013-01-01

The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV–Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane (∼0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are sterically

Prevalence of Allergy to Natural Rubber Latex and Potential Cross Reacting Food in Operation Room Staff in Shiraz Hospitals -2006

OpenAIRE

H Nabavizade; R Amin

2007-01-01

Introduction & Objective: Allergic reactions to natural rubber latex have increased during past 10 years especially among health care workers and patients with high exposure to latex allergens. Allergic reaction to latex is related to many diseases like occupational asthma. This study was performed to determine the prevalence of allergy to natural rubber latex and potential cross reacting food in operation room staff in Shiraz hospitals. Materials & Methods: In this cross-sectional descr...

Ultraviolet curing of epoxidised palm oil acrylate (Epola) and liquid epoxidised natural rubber acrylate (Lenra) on rubberwood substrates-a preliminary study

International Nuclear Information System (INIS)

Mohd Hilmi bin Mahmood; Dahlan bin Hj Mohd; Abdul Ghani bin Harun; Ahmad Shakri bin Mat Seman; Azizol bin Abdul Kadir

1992-01-01

Palm oil based and natural rubber based formulations were cured by ultraviolet (UV) radiation using rubberwood as a substrate. The appearance properties of the cured films were assessed and subjected to mechanical testing. Both formulations gave good finish films. Mechanical tests show that both films can resist abrasion, heat as well as chemical. Overall results show that natural rubber based formulation is superior than palm oil based

Test trial radiation vulcanization of natural rubber latex in Jakarta Indonesia

International Nuclear Information System (INIS)

Devendra, R.; Kulatunge, S.S.; Chandralal, H.N.K.K.; Kalyani, N.M.V.; Seneviratne, J.; Wellage, S.

1994-01-01

Radiation vulcanization of natural rubber latex (RVNRL) can be used to make large quantities of specially stabilized latex. It is possible to obtain RVNRL films of tensile strength over 25 MPa. The films could be either coagulant dipped or cast. It is very important to determine the correct radiation dose which gives the maximum tensile strength. Cross linking density or prevulcanized relax modulus (PRM) at 100% is a reliable property to control the prevulcanization

Development and Characterization of Polymer Eco-Composites Based on Natural Rubber Reinforced with Natural Fibers.

Science.gov (United States)

Stelescu, Maria-Daniela; Manaila, Elena; Craciun, Gabriela; Chirila, Corina

2017-07-11

Natural rubber composites filled with short natural fibers (flax and sawdust) were prepared by blending procedure and the elastomer cross-linking was carried out using benzoyl peroxide. The microbial degradation of composites was carried out by incubating with Aspergillus niger recognized for the ability to grow and degrade a broad range of substrates. The extent of biodegradation was evaluated by weight loss and cross-linking degree study of composites after 2 months incubation in pure shake culture conditions. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) have proved to be precious and valuable instruments for morphological as well as structural characterization of the composites before and after incubation with Aspergillus niger .

Development and Characterization of Polymer Eco-Composites Based on Natural Rubber Reinforced with Natural Fibers

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Maria-Daniela Stelescu

2017-07-01

Full Text Available Natural rubber composites filled with short natural fibers (flax and sawdust were prepared by blending procedure and the elastomer cross-linking was carried out using benzoyl peroxide. The microbial degradation of composites was carried out by incubating with Aspergillus niger recognized for the ability to grow and degrade a broad range of substrates. The extent of biodegradation was evaluated by weight loss and cross-linking degree study of composites after 2 months incubation in pure shake culture conditions. Scanning electron microscopy (SEM and Fourier transform infrared spectroscopy (FT-IR have proved to be precious and valuable instruments for morphological as well as structural characterization of the composites before and after incubation with Aspergillus niger.

Study on the structure-properties relationship of natural rubber/SiO2 composites modified by a novel multi-functional rubber agent

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S. Y. Yang

2014-06-01

Full Text Available Vulcanization property and structure-properties relationship of natural rubber (NR/silica (SiO2 composites modified by a novel multi-functional rubber agent, N-phenyl- N'-(γ-triethoxysilane-propyl thiourea (STU, are investigated in detail. Results from the infrared spectroscopy (IR and X-ray photoelectron spectroscopy (XPS show that STU can graft to the surface of SiO2 under heating, resulting in a fine-dispersed structure in the rubber matrix without the connectivity of SiO2 particles as revealed by transmission electron microscopy (TEM. This modification effect reduces the block vulcanization effect of SiO2 for NR/SiO2/STU compounds under vulcanization process evidently. The 400% modulus and tensile strength of NR/SiO2/STU composites are much higher than that of NR/SiO2/TU composites, although the crystal index at the stretching ratio of 4 and crosslinking densities of NR/SiO2 composites are almost the same at the same dosage of SiO2. Consequently, a structure-property relationship of NR/SiO2/STU composites is proposed that the silane chain of STU can entangle with NR molecular chains to form an interfacial region, which is in accordance with the experimental observations quite well.

2,2,2-Trifluoroethyl methacrylate-graft-natural rubber: Synthesis and application as compatibilizer in natural rubber/fluoroelastomer blends

Energy Technology Data Exchange (ETDEWEB)

Hinchiranan, N., E-mail: nhn78@hotmail.com [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Wannako, P. [Program in Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Paosawatyanyong, B. [Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Prasassarakich, P. [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand)

2013-05-15

The incompatibility and immiscibility of natural rubber (NR)/fluoroelastomers (FKM) blends were improved by incorporation of a graft copolymer synthesized from the free radical graft copolymerization of 2,2,2-trifluoroethyl methacrylate (TFEM) onto NR initiated by benzoyl peroxide via a melt-mixing process. The grafting properties were investigated as functions of the initiator and monomer concentrations, reaction temperature and time. At the optimal conditions, the obtained graft NR (GNR) purified by Soxhlet extraction contained a maximum grafting efficiency of 1.34% with 49.1% monomer conversion. The structure of the purified GNR was analyzed using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy ({sup 1}H NMR and {sup 19}F NMR). The gross GNR was then applied as the compatibilizer for NR/FKM vulcanizates (20/80 (w/w)) cured by peroxide vulcanization. The addition of GNR at 15 parts per hundred of rubber (phr) gave a vulcanizate with the highest tensile strength (9.93 MPa), some 5.31-fold higher than that of the incompatibilized one (1.87 MPa). This is likely to be due to the higher degree of homogeneity of the constituent phases in the GNR-compatibilized blends, as observed by scanning electron microscopy (SEM). The GNR-compatibilized NR/FKM vulcanizates were also resistant to gasohol E85 (85% (w/w) of ethanol). Highlights: ► 2,2,2-Trifluoroethyl methacrylate could be grafted on NR via melt-mixing process. ► Effect of grafting parameters on grafting efficiency and gel content was observed. ► NR/FKM containing graft NR had higher tensile strength than uncompatibilized ones. ► The compatibilized NR/FKM vulcanizates had higher gasohol-swelling resistance.

Study on grafting of monomer onto natural rubber latex by radiation technique

International Nuclear Information System (INIS)

Nguyen Tan Man; Le Hai; Tran Thi Tam; Le Huu Tu, Pham Thi Sam; Dao Minh Phuong; Ha Thuc Huy

2004-01-01

Radiation vulcanization of natural rubber latex has been extensively developed through programmers assisted by the IAEA and UNDP under RCA in Asia and Pacific Region. R-D has been done in most of the Member States with technical assistance from Japan's Takasaki Radiation Chemistry Establishment. Radiation vulcanized natural rubber latex (RVNRL) has many advantages over the conventional sulfur vulcanized latex, such as absence of nitrosamine and low cytotoxicity. Radiation crosslinking is a room temperature process, itself an important cost advantage, it is easily controlled and desired extend of crosslinking is easily achieved by controlling the dose (irradiation time). Disadvantages of RVNRL to be improved are poor physical properties of film such as low tensile strength and tear strength. The research groups of Japan, Thailand and Indonesia concentrated on the improvement of physical properties of RVNRL using radiation grafted PMMA as additive [2]. F. Sundardi and W. Sofiarti have reported that tensile strength and hardness increased by radiation grafting of styrene onto NR [5]. Ono et al have reported the grafting of MMA onto NR by gamma irradiation at a dose of 5 kGy for producing thermoplastic elastomers [4]. The objective of this project is to report the results of studies of radiation graft-copolymerization of methyl methacrylate (MMA) or styrene (St) onto natural rubber latex in order to improve their physico-mechanical properties and evaluation of grafted material using Small-Angle Neutron Scattering through FNCA Project. The grafting degree of MMA and St onto NR increased with the increase of irradiation dose and monomer concentration. The alteration of grafted products structure was determined by IR method. Tensile strength, Shore A hardness, 100% modulus of grafted products increased with the increase of monomer concentration and irradiation dose while elongation at break decreased. The grafted products were characterized by Transmission Electron

Lead zirconate (PbZrO3 embedded in natural rubber as electroactive elastomer composites

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Anuvat Sirivat

2014-11-01

Full Text Available Perovskite lead zirconate (PbZrO3 was synthesized in an orthorhombic form at a temperature below the Curie temperature, TC. The orthorhombic form is a noncentrosymmetric structure which is capable of spontaneous polarization. Fourier transform infrared (FTIR spectra and X-ray diffraction (XRD patterns confirm the successful synthesis of the lead zirconate; and scanning electron microscopy (SEM micrographs indicate that PbZrO3 particles are moderately dispersed in the natural rubber (NR matrix. Without an electrical field, the particles merely act as a ferroelectric filler, which can absorb and store additional stress. Under an electrical field, particle-induced dipole moments are generated, leading to interparticle interaction and a substantial increase in the storage modulus. At a small amount of lead zirconate particulates present in the natural rubber matrix, at a volume fraction of 0.007306, the electrical conductivity increases dramatically by nearly two orders of magnitude at the electrical frequency of 500 kHz.

Aspectos Técnicos en la Producción de Caucho Hevea

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Uribe Henao Alfonso

1950-09-01

Full Text Available El propósito primordial de este trabajo es el de hacer una exposición de los principales factores o aspectos técnicos que deben tenerse en cuenta en el planeamiento y desarrollo del cultivo de la Hevea, para poder obtener de él en la forma más económica el máximo beneficio. Se ha dacio preferencia a los aspectos técnicos concernientes al Hevea de mayor importancia, sin pretender exponerlos todos. No es pues su objetivo dar a conocer todos aquellos detalles y sistemas aconsejables y necesarios en su explotación que pudieran considerarse como principios elementales, y que más bien vienen a ser prácticas corrientes del cultivo.

Soil Nitrogen-Cycling Responses to Conversion of Lowland Forests to Oil Palm and Rubber Plantations in Sumatra, Indonesia.

Directory of Open Access Journals (Sweden)

Kara Allen

Full Text Available Rapid deforestation in Sumatra, Indonesia is presently occurring due to the expansion of palm oil and rubber production, fueled by an increasing global demand. Our study aimed to assess changes in soil-N cycling rates with conversion of forest to oil palm (Elaeis guineensis and rubber (Hevea brasiliensis plantations. In Jambi Province, Sumatra, Indonesia, we selected two soil landscapes - loam and clay Acrisol soils - each with four land-use types: lowland forest and forest with regenerating rubber (hereafter, "jungle rubber" as reference land uses, and rubber and oil palm as converted land uses. Gross soil-N cycling rates were measured using the 15N pool dilution technique with in-situ incubation of soil cores. In the loam Acrisol soil, where fertility was low, microbial biomass, gross N mineralization and NH4+ immobilization were also low and no significant changes were detected with land-use conversion. The clay Acrisol soil which had higher initial fertility based on the reference land uses (i.e. higher pH, organic C, total N, effective cation exchange capacity (ECEC and base saturation (P≤0.05-0.09 had larger microbial biomass and NH4+ transformation rates (P≤0.05 compared to the loam Acrisol soil. Conversion of forest and jungle rubber to rubber and oil palm in the clay Acrisol soil decreased soil fertility which, in turn, reduced microbial biomass and consequently decreased NH4+ transformation rates (P≤0.05-0.09. This was further attested by the correlation of gross N mineralization and microbial biomass N with ECEC, organic C, total N (R=0.51-0. 76; P≤0.05 and C:N ratio (R=-0.71 - -0.75, P≤0.05. Our findings suggest that the larger the initial soil fertility and N availability, the larger the reductions upon land-use conversion. Because soil N availability was dependent on microbial biomass, management practices in converted oil palm and rubber plantations should focus on enriching microbial biomass.

Heavy metals phytoremediation potential of Hevea brasiliensis in Bentong, Malaysia

Science.gov (United States)

Yusof, Muhammad Jefri Mohd; Latif, Mohd Talip; Yusoff, Siti Fairus Mohd

2018-04-01

Biomonitoring uses living organisms to assess environmental quality and being preferred over conventional methods that use fully or semi-automatic gauges for its lower cost and practicality. Recently, higher plants are widely used for biomonitoring purposes by means of their species identification simplicity, larger availability of biological substantial, and easy to sample. In this study, samples of Hevea brasiliensis (i.e leaves, barks, and latex as well as surrounding soils) from outskirts of Pelangai, Bentong were tested for heavy metals by using inductively coupled plasma optical emission spectroscopy (ICP-OES). Enrichment factor of soils indicated that some metals (B, Ca, Cu, Mn, Pb, Zn, As and Na) were anthropogenic which most likely originated from traffic emissions. In addition, leaves trapped the most heavy metals compared to barks and latex. The accumulation of pollutants in those samples has identified biomonitoring abilities of Hevea brasiliensis.

An overview of the potentials of natural rubber (Hevea brasiliensis ...

African Journals Online (AJOL)

STORAGESEVER

2009-12-29

Dec 29, 2009 ... brasiliensis) engineering for the production of valuable proteins ... years gestation period and economic life of about 25 years. ... reactors) involve processes well entrenched in industry. ... plant (low cost of maintenance, simple clonal propaga- .... such as industrial enzymes or proteins used in personal.

Advances in rubber/halloysite nanotubes nanocomposites.

Science.gov (United States)

Jia, Zhixin; Guo, Baochun; Jia, Demin

2014-02-01

The research advances in rubber/halloysite nanotubes (rubber/HNTs) nanocomposites are reviewed. HNTs are environmentally-friendly natural nanomaterials, which could be used to prepare the rubber-based nanocomposites with high performance and low cost. Unmodified HNTs could be adopted to prepare the rubber/HNTs composites with improved mechanical properties, however, the rubber/HNTs nanocomposites with fine morphology and excellent properties were chiefly prepared with various modifiers by in situ mixing method. A series of rubber/HNTs nanocomposites containing several rubbers (SBR, NR, xSBR, NBR, PU) and different modifiers (ENR, RH, Si69, SA, MAA, ILs) have been investigated. The results showed that all the rubber/HNTs nanocomposites achieved strong interfacial interaction via interfacial covalent bonds, hydrogen bonds or multiple interactions, realized significantly improved dispersion of HNTs at nanoscale and exhibited excellent mechanical performances and other properties.

Reinforcing effect of plasma modified halloysite nanotubes in a carbon black filled natural rubber-butadien rubber matrix

NARCIS (Netherlands)

Poikelispaa, Minna; Das, Amit; Dierkes, Wilma K.; Vuorinen, Jyrki

2011-01-01

Rubber composites are generally produced by the direct incorporation of fillers like carbon black and/or silica into the rubber matrix. The incorporation of different types of nanofillers is the subject of recent research with the aim of preparing composites with special compositions and properties.

In vitro culture method of powdery mildew (Oidium heveae ...

African Journals Online (AJOL)

ELOHO

2012-08-23

Aug 23, 2012 ... A method for culturing powdery mildew (Oidium heveae) from isolated leaves of ... solution; d, Colour phase leaves with nutrient solution in culture dish; e, in vitro ... Plant and fungus materials .... same change trend during whole culture period. ... consistent with the field resistance identification results of.

Multiwall carbon nanotube-filled natural rubber: Electrical and mechanical properties

Directory of Open Access Journals (Sweden)

L. Bokobza

2012-03-01

Full Text Available The influence of multiwall carbon nanotube (MWNTs contents on electrical and mechanical properties of MWNTs-reinforced natural rubber (NR composites is studied. The volume resistivity of the composites decreases with increasing the MWNTs content and the electrical percolation threshold is reached at less than 1 phr of MWNTs (phr = parts of filler by weight per hundred parts of rubber. This is caused by the formation of conductive chains in the composites. Electrical measurements under uniaxial deformation of a composite carried out at a filler loading above the percolation threshold, indicate a gradual disconnection of the conducting network with the bulk deformation. The drop in the storage modulus G' with the shear strain amplitude (Payne effect is also attributed to a breakdown of the filler network. Considerable improvement in the stiffness is obtained upon incorporation of MWNTs in the polymer matrix but the main factor for reinforcement of NR by MWNTs appears to be their high aspect ratio rather than strong interfacial interaction with rubber. The tensile strength and the elongation at break of the composites are reduced with regard to the unfilled sample. This is probably due to the presence of some agglomerates that increase with the nanotube content. This hypothesis is confirmed by a cyclic loading of the composites where it is seen that the deformation at break occurs at a much higher level of strain in the second stretch than in the first one. The overall significant property improvements are the result of a better nanotube dispersion attributed to the combined use of tip sonication and cyclohexane as dispersion aids during composite processing.

Hevea brasiliensis Muell Arg.

African Journals Online (AJOL)

AISA

Sucrose and inorganic phosphorus exhibited best tendencies to predict yield potential of rubber tree clones at old age. .... molybdate d'ammonium (Mo), puis le complexe est lui-même réduit par du sulfate .... Pi : inorganic phosphorus ; Prod : Production ; Sac : Sucrose ; Exs: Dry rubber R-SH : thiols. "0" : without stimulation ;.

Genome-wide identification of Jatropha curcas aquaporin genes and the comparative analysis provides insights into the gene family expansion and evolution in Hevea brasiliensis

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Zhi eZou

2016-03-01

Full Text Available Aquaporins (AQPs are channel-forming integral membrane proteins that transport water and other small solutes across biological membranes. Despite the vital role of AQPs, to date, little is known in physic nut (Jatropha curcas L., Euphorbiaceae, an important non-edible oilseed crop with great potential for the production of biodiesel. In this study, 32 AQP genes were identified from the physic nut genome and the family number is relatively small in comparison to 51 in another Euphorbiaceae plant, rubber tree (Hevea brasiliensis Muell. Arg.. Based on the phylogenetic analysis, the JcAQPs were assigned to five subfamilies, i.e., 9 plasma membrane intrinsic proteins (PIPs, 9 tonoplast intrinsic proteins (TIPs, 8 NOD26-like intrinsic proteins (NIPs, 2 X intrinsic proteins (XIPs and 4 small basic intrinsic proteins (SIPs. Like rubber tree and other plant species, functional prediction based on the aromatic/arginine selectivity filter, Froger’s positions and specificity-determining positions showed a remarkable difference in substrate specificity among subfamilies of JcAQPs. Genome-wide comparative analysis revealed the specific expansion of PIP and TIP subfamilies in rubber tree and the specific gene loss of the XIP subfamily in physic nut. Furthermore, by analyzing deep transcriptome sequencing data, the expression evolution especially the expression divergence of duplicated HbAQP genes was also investigated and discussed. Results obtained from this study not only provide valuable information for future functional analysis and utilization of Jc/HbAQP genes, but also provide a useful reference to survey the gene family expansion and evolution in Euphorbiaceae plants and other plant species.

Antioxidant and sensitizer effect on the stability of natural rubber latex vulcanized by gamma rays

International Nuclear Information System (INIS)

Canavel, V.

1993-01-01

The natural rubber latex was vulcanized by gamma rays and electrons beam, in the presence and absence of sensitizer at room temperature. The sensitizers were the following; n-butyl acrylate (n-BA) / t-butyl hydroperoxide (t-B H) / KOH, C Cl 4 / potassium laurate and n-BA / KOH. The studied antioxidants, Irganox 1520, Vulcanox SP and Vulcanox BKF, were added to the latex after irradiation. Among the studied antioxidants in function of tensile strength (TS) after the aging of rubber plates, the Irganox was the best efficient on the gamma vulcanization in the presence of n-BA/t-B H/KOH, because only 0,20 p hr is enough to obtain the greatest increase of TS, that was 34%, 12 MPa to 16 MPa. The formulating method of latex with the sensitizer constituted the 3,0 p hr of n-BA/ 0,1 p hr of t-B H and 0,2 p hr of KOH, was evaluated respecting the TS of rubber plates. The electrons beam vulcanization produces the greatest reversible perturbance in the colloidal stability of latex after irradiation caused by radiolytic species absorption that promotes the increase of particle size. The antioxidant also contributes to reversible destabilization of gamma irradiated latex, because it is also adsorbed by particles surface. The relation between the latex viscosity and the TS of respective rubber plates is reverse, showing the latex stability affects the quality of rubber goods. (author)

Preparation of highly stabilised natural rubber latex for radiation vulcanisation

International Nuclear Information System (INIS)

Kulatunge, S.S.; Nadarajah, M.; Kalyani, N.M.V.; Chandralal, H.N.K.K.; Devendra, R.

1996-01-01

There is a bright future for radiation vulcanised natural rubber latex (RVNRL) but there are problems in manufacturing it as the centrifuged latex to be used for radiation has to be kept for at least a month or sometimes even three to six months before adding the sensitisers and even then the latex sometimes coagulates on adding the sensitisers. This paper describes a process by which the latex can be stabilised by addition of an anionic soap before centrifuging so that it has a high mechanical stability and hence can be used even within one week of the manufacture of the centrifuged latex

The Effect of Paraffin Wax to Properties of Radiation Vulcanization Natural Rubber Latex (RVNRL)

International Nuclear Information System (INIS)

Mohd Noorwadi Mat Lazim; Sofian Ibrahim; Muhammad Saiful Omar

2015-01-01

Dipping factories often encounter a serious problem with high tackiness of the finish products during storage. The tackiness effect can be lead to rejection of products. This tackiness effect of natural (NR) rubber film originates in the free rubber chain ends at the surface of the film. The tackiness is not depends on the degree of crosslinking (vulcanization), since radiation itself unable to reduce the tackiness effect. The RVNRL requires addition of additive or anti-tack agent into formulation to reduce tackiness effect. In this experiment, paraffin wax manufactured by Emulco Sdn Bhd under the trade name Aquawax 48 was added into RVNRL formulation as anti-tack and the effect of paraffin wax to physical and mechanical properties of RVNRL was study. (author)

Surgical gloves fabrication using natural rubber latex vulcanized with gamma radiation

International Nuclear Information System (INIS)

Collantes, Hugo David Chirinos.

1995-01-01

Surgical gloves were manufactured by immersion coagulant method from vulcanized natural rubber latex by gamma rays at dose of 10 kGy in the air, at room temperature, using the following sensitizer vulcanization An-B 3 phr/KOH 0.2 phr. The influence of the parameter in the thickness of the surgical gloves manufacture, studied through fractional factorial designs technic, can be resumed by empirical linear correlation: y = 0.213 + 0.025 [Ca Cl 2 ] + 0.019 t. (author). 49 refs., 13 figs., 31 tabs

Greenhouse Gas Emissions from Rubber Industry in Thailand

NARCIS (Netherlands)

Jawjit, W.; Kroeze, C.; Rattanapan, S.

2010-01-01

Rubber production has been taking place in Thailand for many decades. Thailand is currently the world's largest natural rubber producer. We present emissions of greenhouse gases associated with the production of fresh latex, and three primary rubber products, including concentrated latex, block

Thermal Characterization of Modified Tacca Leontopetaloides Starch and Natural Rubber Based Thermoplastic Elastomer

International Nuclear Information System (INIS)

Ainatul Mardhiah Mohd Amin; Nur Shahidah Ab Aziz; Nurul Shuhada Mohd Makhtar; Miradatul Najwa Mohd Rodhi; Suhaila Mohd Sauid

2014-01-01

The purpose of this study is to identify the potential of Tacca leontopetaloides starch as bio-based thermoplastic elastomers, TPEs. Starch based polymer had been recognized to have highly potential in replace existing source of conventional elastomeric polymer. The modification process of blending starch with natural rubber, plasticizers, additives, and filler contribute to the enhancement and improvement for the properties of starch in order to produce biopolymers by approaching the properties of TPEs. Thermal properties of starch based thermoplastic was studied to evaluate the decomposition and degradation of the samples by using Thermogravimetric Analysis, TGA while the properties of endothermic reactions of the samples were thermally analyzed via Differential Scanning Calorimetry, DSC. From the analysis, it was found that the thermal properties of samples were revealed by recognizing GM-2 (green materials, GM) has high thermal resistance towards high temperature up to 480.06 degree Celsius with higher amount of residue which is 4.97 mg compared to other samples. This indicates GM-2 comprises of superior combination of ratio between natural rubbers and glycerol (plasticizer) in purpose of approaching the properties of Thermoplastic Elastomers, TPEs. (author)

Soil Nitrogen-Cycling Responses to Conversion of Lowland Forests to Oil Palm and Rubber Plantations in Sumatra, Indonesia

Science.gov (United States)

Tjoa, Aiyen; Veldkamp, Edzo

2015-01-01

Rapid deforestation in Sumatra, Indonesia is presently occurring due to the expansion of palm oil and rubber production, fueled by an increasing global demand. Our study aimed to assess changes in soil-N cycling rates with conversion of forest to oil palm (Elaeis guineensis) and rubber (Hevea brasiliensis) plantations. In Jambi Province, Sumatra, Indonesia, we selected two soil landscapes – loam and clay Acrisol soils – each with four land-use types: lowland forest and forest with regenerating rubber (hereafter, “jungle rubber”) as reference land uses, and rubber and oil palm as converted land uses. Gross soil-N cycling rates were measured using the 15N pool dilution technique with in-situ incubation of soil cores. In the loam Acrisol soil, where fertility was low, microbial biomass, gross N mineralization and NH4 + immobilization were also low and no significant changes were detected with land-use conversion. The clay Acrisol soil which had higher initial fertility based on the reference land uses (i.e. higher pH, organic C, total N, effective cation exchange capacity (ECEC) and base saturation) (P≤0.05–0.09) had larger microbial biomass and NH4 + transformation rates (P≤0.05) compared to the loam Acrisol soil. Conversion of forest and jungle rubber to rubber and oil palm in the clay Acrisol soil decreased soil fertility which, in turn, reduced microbial biomass and consequently decreased NH4 + transformation rates (P≤0.05–0.09). This was further attested by the correlation of gross N mineralization and microbial biomass N with ECEC, organic C, total N (R=0.51–0. 76; P≤0.05) and C:N ratio (R=-0.71 – -0.75, P≤0.05). Our findings suggest that the larger the initial soil fertility and N availability, the larger the reductions upon land-use conversion. Because soil N availability was dependent on microbial biomass, management practices in converted oil palm and rubber plantations should focus on enriching microbial biomass. PMID:26222690

New Insights into the Relationship Between Network Structure and Strain Induced Crystallization in Unvolcanized Natural Rubber by Synchrotron X-ray Diffraction

International Nuclear Information System (INIS)

Toki, S.; Hsiao, B.; Amnuaypornsri, S.; Sakdapipanich, J.

2009-01-01

The relationship between the network structure and strain-induced crystallization in un-vulcanized as well as vulcanized natural rubbers (NR) and synthetic poly-isoprene rubbers (IR) was investigated via synchrotron wide-angle X-ray diffraction (WAXD) technique. It was found that the presence of a naturally occurring network structure formed by natural components in un-vulcanized NR significantly facilitates strain-induced crystallization and enhances modulus and tensile strength. The stress-strain relation in vulcanized NR is due to the combined effect of chemical and naturally occurring networks. The weakness of naturally occurring network against stress and temperature suggests that vulcanized NR has additional relaxation mechanism due to naturally occurring network. The superior mechanical properties in NR compared with IR are mainly due to the existence of naturally occurring network structure.

Preparation of Non-Woven Fiber Mats by Mixture of PVC and Epoxidized Natural Rubber

International Nuclear Information System (INIS)

Muhammad Hariz Othman; Mahathir Mohamed; Dahlan Mohd

2014-01-01

Eletrospun non-woven fibre mats prepared from ENR modified PVC were successfully fabricated at ambient temperature by electro spinning method. Liquid epoxidized natural rubber (LENR) was used because it is easier to handle compared to dried ENR. PVC was mixed with LENR based on 3 different ratios (9:1, 8:2 and 7:3). The effect of ENR on electrospinnibality of PVC was investigated.The morphologies and thermal properties of the electro span fibre mats were characterized and assessed using scanning calorimetry (DSC). The polymer solution concentration 16 aut % formed a diameter of the fibres were mainly affected by the addition of natural rubber and weight ratio of the solution. The diameter of the fibres also decreased with increasing amount of LENR in the solution. Thermal degradation involved two-step degradation with the first degradation representing the dehydro chlorination of PVC to form polyene and followed by the decomposition of LENR and the polyene.Addition of LENR into the sample caused the T g of electro spun fibre mats of PVC/LENR to shift toward lower temperature. (author)

High performance natural rubber composites with a hierarchical reinforcement structure of carbon nanotube modified natural fibers

International Nuclear Information System (INIS)

Tzounis, Lazaros; Debnath, Subhas; Rooj, Sandip; Fischer, Dieter; Mäder, Edith; Das, Amit; Stamm, Manfred; Heinrich, Gert

2014-01-01

A simple and facile method for depositing multiwall carbon nanotubes (MWCNTs) onto the surface of naturally occurring short jute fibers (JFs) is reported. Hierarchical multi-scale structures were formed with CNT-networks uniformly distributed and fully covering the JFs (JF–CNT), as depicted by the scanning electron microscopy (SEM) micrographs. The impact of these hybrid fillers on the mechanical properties of a natural rubber (NR) matrix was systematically investigated. Pristine JFs were cut initially to an average length of 2.0 mm and exposed to an alkali treatment (a-JFs) to remove impurities existing in the raw jute. MWCNTs were treated under mild acidic conditions to generate carboxylic acid moieties. Afterward, MWCNTs were dispersed in an aqueous media and short a-JFs were allowed to react with them. Raman spectroscopy confirmed the chemical interaction between CNTs and JFs. The JF–CNT exposed quite hydrophobic behavior as revealed by the water contact angle measurements, improving the wettability of the non-polar NR. Consequently, the composite interfacial adhesion strength was significantly enhanced while a micro-scale “mechanical interlocking” mechanism was observed from the interphase-section transmission electron microscopy (TEM) images. SEM analysis of the composite fracture surfaces demonstrated the interfacial strength of NR/a-JF and NR/JF–CNT composites, at different fiber loadings. It can be presumed that the CNT-coating effectively compatibillized the composite structure acting as a macromolecular coupling agent. A detailed analysis of stress-strain and dynamic mechanical spectra confirmed the high mechanical performance of the hierarchical composites, consisting mainly of materials arising from natural resources. - Highlights: • Natural rubber (NR) composites reinforced with CNT-modified short jute fibers. • MWCNTs deposited to the surface of jute fibers via non-covalent interactions. • Hierarchical reinforcement structure with

Phenotypic stability and genetic gains in six-year girth growth of Hevea clones

Directory of Open Access Journals (Sweden)

Paulo de Souza Gonçalves

1999-07-01

Full Text Available Rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss. Müell. Arg.] budgrafts of seven clones were evaluated on five contrasting sites in the plateau region of the São Paulo State, Brazil. The objective of this work was to study the phenotypic stability for girth growth. The experimental design was a randomized block design with three replications and seven treatments. Analysis of variance of girth at six-year plant growth indicated a highly significant clone x site interaction. Only linear sites and clone x site components of clone x year interaction were significant, indicating that the performance of clones over sites for this trait could be predicted. The clones GT 1 and PB 235 showed the greatest stability in relation to girth growth, with foreseen responses to change, introduced in the sites. The clones PB 235 and IAN 873 showed significative difference in relation to regression coefficient, representing clones with specific adaptability on favorable and unfavorable sites respectively. The clone GT 1 became the most promissory one in the study of stability and adaptability even showing low girth growth. Expected genetic gains from planting sites, along with estimates of clonal variance and repeatability of clonal means are generally greatest or close to the greatest when selection is done at the same site.

Radiation induced grafting of monomers onto natural rubber : processes and applications

International Nuclear Information System (INIS)

Sunny Sebastian, M.

2001-01-01

Full text: Certain inherent mechanical properties of natural rubber (NR) can be modified by grafting vinyl monomers onto the polymer backbone. This paper described the gamma radiation induced graft copolymerization of methyl methacrylate (MMA), styrene and acrylonitrile (AN) onto NR. The graft copolymers can be crosslinked by sulphur and organic accelerators. The crosslinked graft copolymers show improved modulus and hardness in their films compared to NR. However the tensile strength of the films is reduced by grafting. The methods for preparing the graft copolymers, their properties and applications are briefly described

Mapping Rubber Plantations and Natural Forests in Xishuangbanna (Southwest China Using Multi-Spectral Phenological Metrics from MODIS Time Series

Directory of Open Access Journals (Sweden)

Sebastian van der Linden

2013-05-01

Full Text Available We developed and evaluated a new approach for mapping rubber plantations and natural forests in one of Southeast Asia’s biodiversity hot spots, Xishuangbanna in China. We used a one-year annual time series of Moderate Resolution Imaging Spectroradiometer (MODIS, Enhanced Vegetation Index (EVI and short-wave infrared (SWIR reflectance data to develop phenological metrics. These phenological metrics were used to classify rubber plantations and forests with the Random Forest classification algorithm. We evaluated which key phenological characteristics were important to discriminate rubber plantations and natural forests by estimating the influence of each metric on the classification accuracy. As a benchmark, we compared the best classification with a classification based on the full, fitted time series data. Overall classification accuracies derived from EVI and SWIR time series alone were 64.4% and 67.9%, respectively. Combining the phenological metrics from EVI and SWIR time series improved the accuracy to 73.5%. Using the full, smoothed time series data instead of metrics derived from the time series improved the overall accuracy only slightly (1.3%, indicating that the phenological metrics were sufficient to explain the seasonal changes captured by the MODIS time series. The results demonstrate a promising utility of phenological metrics for mapping and monitoring rubber expansion with MODIS.

Latex production with depolymerizing compounds of actin cytoskeleton in rubber trees Produção de látex estimulada pela aplicação de compostos despolimerizantes de citoesqueleto de actina em seringueiras

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Gao Zheng-Quan

2008-02-01

Full Text Available The objective of this work was to assess stimulated latex flow from rubber trees (Hevea brasiliensis with saturated macrolide (latrunculin A, 1, 5, and 10% potassium iodide in 2% methylcellulose compared with 0.3% ethylene in 2% methylcellulose (check and 2% methylcellulose (blank. Latex output and contents of pure rubber, total solid, sucrose, inorganic phosphorus, thiol, and Mg2+ were measured. The treatments containing 1% KI or saturated macrolide increased latex yields compared to the blank with 2% methylcellulose alone. The 1% KI or saturated macrolide treatments were equal to that of 0.3% ethylene check treatment. However, 5 and 10% KI were harmful to bark of rubber trees, even caused prolonged tapping panel dryness.O objetivo deste trabalho foi avaliar a produção de látex em seringueiras (Hevea brasiliensis estimulada pela aplicação de macrolídeo saturado (latrunculina A, iodeto de potássio a 1, 5 e 10%, e etileno a 0,3%, preparados em solução de metilcelulose a 0,2%. O tratamento testemunha consistiu da aplicação de solução pura de metilcelulose a 2%. Foram medidos a produção de látex e o conteúdo de borracha pura, sólidos totais, sacarose, fósforo inorgânico, tiol e Mg2+. A aplicação de KI a 1% ou de macrolídeo saturado aumentou a produção de látex em comparação com o tratamento testemunha. Os tratamentos com KI a 1% e macrolídeo saturado foram iguais ao tratamento com etileno a 0,3%. No entanto, os tratamentos com KI a 5 e 10% foram prejudiciais à casca da seringueira, causando até mesmo o secamento do painel-de-sangria.

Investigations on the properties of NH4HCO3 filled natural rubber based magnetorheological elastomers (MREs)

Science.gov (United States)

Fan, Lili; Wang, Guoping; Wang, Wenju; Shi, Guanxin; Yang, Fufeng; Rui, Xiaoting

2018-04-01

Various anisotropic magnetorheological elastomers (MREs) were synthesized using the rubber mixing technique. Magnetic and temperature distributions of the experimental equipment and test instruments were analyzed by the ANSYS. NH4HCO3 was filled in the natural rubber matrix to modify properties of MREs. Microstructures and compositions of samples were studied by the scanning electron microscope (SEM), the energy dispersive x-ray spectroscopy (EDAX) analysis and x-ray powder diffraction (XRD). Via vibrating sample magnetometer (VSM) and density functional theory (DFT) method, the magnetic property of carbonyl iron (CI) was illuminated. The shear storage modulus and MR effect of MREs were investigated by the dynamic mechanical analyzer (DMA). It indicated that distributions of magnetic and temperature in the experimental and testing devices were uniform. Before vulcanization, CI particles were uniformly distributed in the matrix, while a CI chain structure was formed and embedded in the matrix after the vulcanization process. Moderate addition of NH4HCO3 accelerated the rubber vulcanization and enhanced the MR effect.

Radiation vulcanization of natural rubber latex with low energy accelerator

Energy Technology Data Exchange (ETDEWEB)

Haque, Emdadul; Makuuchi, Keizo; Ikeda, Kenichi; Yoshii, Fumio; Kume Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Mitomo, Hiroshi [Gunma Univ., Faculty of Engineering, Department of Biological and Chemical Engineering, Kiryu, Gunma (Japan)

2001-03-01

The radiation vulcanization of natural rubber latex (RVNRL) with the recently installed electron beam (EB) pilot plant at Takasaki Radiation Chemistry Research Establishment, Takasaki, Japan has been discussed. The accelerating voltage and beam current of the plant are 250 kV and 10 mA respectively. The plant has a reaction vessel with the capacity of 18 liters latex to irradiate at a time. In order to obtain a suitable setting of experimental for RVNRL under EB of the plant the parameters such as irradiation time, defoamer concentration, volume of latex, beam current etc. are being optimized by varying the individual parameter at a constant set of the other variables. (author)

Exposure to rubber fume and rubber process dust in the general rubber goods, tyre manufacturing and retread industries.

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Dost, A A; Redman, D; Cox, G

2000-08-01

This study assesses the current patterns and levels of exposure to rubber fume and rubber process dust in the British rubber industry and compares and contrasts the data obtained from the general rubber goods (GRG), retread tire (RT) and new tire (NT) sectors. A total of 179 rubber companies were visited and data were obtained from 52 general rubber goods, 29 retread tire and 7 new tire manufacturers. The survey was conducted using a questionnaire and included a walk-through inspection of the workplace to assess the extent of use of control measures and the nature of work practices being employed. The most recent (predominantly 1995-97) exposure monitoring data for rubber fume and rubber process dust were obtained from these companies; no additional sampling was conducted for the purpose of this study. In addition to the assessment of exposure data, evaluation of occupational hygiene reports for the quality of information and advice was also carried out.A comparison of the median exposures for processes showed that the order of exposure to rubber fume (E, in mg m(-3)) is: E(moulding) (0.40) approximately E(extrusion) (0.33)>E(milling) (0.18) for GRG; E(press) (0. 32)>E(extrusion) (0.19)>E(autoclave) (0.10) for RT; and E(press) (0. 22) approximately E(all other) (0.22) for NT. The order of exposure to rubber fume between sectors was E(GRG) (0.40)>E(RT) (0.32)>E(NT) (0.22). Median exposures to rubber process dust in the GRG was E(weighing) (4.2)>E(mixing) (1.2) approximately E(milling) (0.8) approximately E(extrusion) (0.8) and no significant difference (P=0. 31) between GRG and NT sectors. The findings compare well with the study carried out in the Netherlands [Kromhout et al. (1994), Annals of Occupational Hygiene 38(1), 3-22], and it is suggested that the factors governing the significant differences noted between the three sectors relate principally to the production and task functions and also to the extent of controls employed. Evaluation of occupational

Development of magnetorheological elastomers based on Deproteinised natural rubber as smart damping materials

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Ismail, Nik Intan Nik; Kamaruddin, Shamsul

2017-12-01

Magnetorheological elastomers (MREs) are composite materials consist of micron-sized magnetizable particles carbonyl iron particles [CIPs]) embedded in a soft elastomer matrix. MRE technology offers variable stiffness and damping properties under the influence of a magnetic field. Herein, the feasibility of incorporating a new generation specialty rubber, Pureprena as a matrix for MREs was investigated. Pureprena or Deproteinised Natural Rubber (DPNR) is a specialty natural rubber that has good dynamic properties, particularly with respect to damping parameters. DPNR was compounded with 60 wt% of CIPs to fabricate MREs. The performance of the DPNR-based MRE was measured in terms of tensile strength, dynamic properties, and magnetorheological (MR) effect and compared with polyisoprene (IR)-based MRE with the same amount of CIPs. Dynamic Mechanical Analyzer (DMA) showed that the loss factor in the glass transition region of the DPNR-based MRE was higher than that of the IR-based MRE, indicating better damping properties. Further investigation was undertaken using a servo-hydraulic testing machine to characterise the effect of strain amplitude and frequency on the dynamic properties (e.g. damping coefficient) of MREs at zero magnetic fields. The results demonstrate that DPNR-based MREs possess a comparable damping coefficient to that of IR-based MREs. In addition, MR effect, which relates to the ratio between elastic modulus with applied magnetic field (on-state) to the same modulus without applied fields (off-state), was measured using a parallel plate rheometer. As a result, DPNR-based MREs have improved MR effect than that of IR-based MREs. Moreover, variable stiffness is obtained when the magnetic field was increased to 0.8T. Loss factor or tan δ of MREs was found to vary against different magnetic fields. Finally, MREs with varied stiffness and damping were found to have potential as active control devices for smart damping materials.

Multilayer graphene rubber nanocomposites

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Schartel, Bernhard; Frasca, Daniele; Schulze, Dietmar; Wachtendorf, Volker; Krafft, Bernd; Morys, Michael; Böhning, Martin; Rybak, Thomas

2016-05-01

Multilayer Graphene (MLG), a nanoparticle with a specific surface of BET = 250 m2/g and thus made of only approximately 10 graphene sheets, is proposed as a nanofiller for rubbers. When homogenously dispersed, it works at low loadings enabling the replacement of carbon black (CB), increase in efficiency, or reduction in filler concentration. Actually the appropriate preparation yielded nanocomposites in which just 3 phr are sufficient to significantly improve the rheological, curing and mechanical properties of different rubbers, as shown for Chlorine-Isobutylene-Isoprene Rubber (CIIR), Nitrile-Butadiene Rubber (NBR), Natural Rubber (NR), and Styrene-Butadiene Rubber (SBR). A mere 3 phr of MLG tripled the Young's modulus of CIIR, an effect equivalent to 20 phr of carbon black. Similar equivalents are observed for MLG/CB mixtures. MLG reduces gas permeability, increases thermal and electrical conductivities, and retards fire behavior. The later shown by the reduction in heat release rate in the cone calorimeter. The higher the nanofiller concentration is (3 phr, 5 phr, and 10 phr was investigated), the greater the improvement in the properties of the nanocomposites. Moreover, the MLG nanocomposites improve stability of mechanical properties against weathering. An increase in UV-absorption as well as a pronounced radical scavenging are proposed and were proved experimentally. To sum up, MLG is interesting as a multifunctional nanofiller and seems to be quite ready for rubber development.

Adaptive neuro-fuzzy inference system for forecasting rubber milk production

Science.gov (United States)

Rahmat, R. F.; Nurmawan; Sembiring, S.; Syahputra, M. F.; Fadli

2018-02-01

Natural Rubber is classified as the top export commodity in Indonesia. Its high production leads to a significant contribution to Indonesia’s foreign exchange. Before natural rubber ready to be exported to another country, the production of rubber milk becomes the primary concern. In this research, we use adaptive neuro-fuzzy inference system (ANFIS) to do rubber milk production forecasting. The data presented here is taken from PT. Anglo Eastern Plantation (AEP), which has high data variance and range for rubber milk production. Our data will span from January 2009 until December 2015. The best forecasting result is 1,182% in term of Mean Absolute Percentage Error (MAPE).

Energy usage in the rubber industry

Energy Technology Data Exchange (ETDEWEB)

Soederstroem, M.

1980-01-01

The rubber industry has several energy-intensive steps, such as mastication of natural rubber, mixing and extrusion, and vulcanization. Opportunities for energy savings would be available with a continuous mixing process, heat recovery from cooling waters, and abandonment of thermal conduction in vulcanization. 6 figures. (DCK)

Preparation and properties of natural rubber reinforced with polydopamine-coating modified carbon nanotubes

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Y-L. Lu

2017-01-01

Full Text Available Multi-walled carbon nanotubes (MWCNTs were functionalized by polydopamine (PDA-coating and mixed with natural rubber (NR via latex compounding. Compared with pristine MWCNTs, the surface of MWCNT-PDA was covered by an amorphous and nanometer-scale PDA layer which had a large amount of oxygenic and nitric functional groups. So the MWCNT-PDA showed a perfect dispersion in NR matrix. The tensile strength of NR/MWCNT-PDA (5 phr composites is 28.6 MPa, compared with the pure NR, which increased by 42%. For the electrical properties, when the content of MWCNTPDA or MWCNTs is 2 phr, the volume resistivity of NR/MWCNT-PDA composites falls to about 2.7·109 Ω·cm, compared with 3.3·1013 Ω·cm of NR/MWCNT composites. The thermal conductivity of NR composites increased only by 28.2% when 5 phr MWCNT-PDA was added. A model proposed by Nan was used to calculate the thermal conductivity of NR/MWCNT composites, and the calculated values were compared with the experimental values, the results showed that the interface thermal resistance is the main reason why MWCNTs could not significantly increase the thermal conductivity of natural rubber.

Mechanical Enhancement of Sensitivity in Natural Rubber Using Electrolytic Polymerization Aided by a Magnetic Field and MCF for Application in Haptic Sensors.

Science.gov (United States)

Shimada, Kunio; Saga, Norihiko

2016-09-18

Sensors are essential to the fulfillment of every condition of haptic technology, and they need simultaneously to sense shear stress as well as normal force, and temperature. They also must have a strong and simple structure, softness, and large extension. To achieve these conditions simultaneously, we enhanced the sensitivity of sensors utilizing natural rubber (NR)-latex through the application of electrolytic polymerization focused on the isoprene C=C bonds in natural rubbers such as NR-latex, and then applied a magnetic field and magnetic compound fluid (MCF) as magnetically responsive fluid. When an electric field alone was used in the rubber, the effect of electrolytic polymerization was very small compared to the effect in well-known conductive polymer solution such as plastic. The MCF developed by Shimada in 2001 involved magnetite and metal particles, and acts as a filler in NR-latex. By utilizing the magnetic, electric fields and the MCF, we aligned the electrolytically polymerized C=C along the magnetic field line with the magnetic clusters formed by the aggregation of magnetite and metal particles so as to enhance the effect of electrolytic polymerization. We then demonstrated the effectiveness of the new method of rubber vulcanization on the sensitivity of the rubber by experimentally investigating its electric and dynamic characteristics.

Mechanical Enhancement of Sensitivity in Natural Rubber Using Electrolytic Polymerization Aided by a Magnetic Field and MCF for Application in Haptic Sensors

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Kunio Shimada

2016-09-01

Full Text Available Sensors are essential to the fulfillment of every condition of haptic technology, and they need simultaneously to sense shear stress as well as normal force, and temperature. They also must have a strong and simple structure, softness, and large extension. To achieve these conditions simultaneously, we enhanced the sensitivity of sensors utilizing natural rubber (NR-latex through the application of electrolytic polymerization focused on the isoprene C=C bonds in natural rubbers such as NR-latex, and then applied a magnetic field and magnetic compound fluid (MCF as magnetically responsive fluid. When an electric field alone was used in the rubber, the effect of electrolytic polymerization was very small compared to the effect in well-known conductive polymer solution such as plastic. The MCF developed by Shimada in 2001 involved magnetite and metal particles, and acts as a filler in NR-latex. By utilizing the magnetic, electric fields and the MCF, we aligned the electrolytically polymerized C=C along the magnetic field line with the magnetic clusters formed by the aggregation of magnetite and metal particles so as to enhance the effect of electrolytic polymerization. We then demonstrated the effectiveness of the new method of rubber vulcanization on the sensitivity of the rubber by experimentally investigating its electric and dynamic characteristics.

The partial replacement of palm kernel shell by carbon black and halloysite nanotubes as fillers in natural rubber composites

Science.gov (United States)

Daud, Shuhairiah; Ismail, Hanafi; Bakar, Azhar Abu

2017-07-01

The effect of partial replacement of palm kernel shell powder by carbon black (CB) and halloysite nanotube (HNT) on the tensile properties, rubber-filler interaction, thermal properties and morphological studies of natural rubber (NR) composites were investigated. Four different compositions of NR/PKS/CB and NR/PKS/HNT composites i.e 20/0, 15/5, 10/10,5/15 and 0/20 parts per hundred rubber (phr) were prepared on a two roll mill. The results showed that the tensile strength and modulus at 100% elongation (M100) and 300% elongation (M300) were higher for NR/PKS/CB compared to NR/PKS/HNT composites. NR/PKS/CB composites had the lowest elongation at break (Eb). The effect of commercial fillers in NR/PKS composites on tensile properties was confirmed by the rubber-filler interaction and scanning electron microscopy (SEM) study. The thermal stability of PKS filled NR composites with partially replaced by commercial fillers also determined by Thermo gravimetric Analysis (TGA).

Estimating the concentration of gold nanoparticles incorporated on natural rubber membranes using multi-level starlet optimal segmentation

Energy Technology Data Exchange (ETDEWEB)

Siqueira, A. F. de, E-mail: siqueiraaf@gmail.com; Cabrera, F. C., E-mail: flavioccabrera@yahoo.com.br [UNESP – Univ Estadual Paulista, Dep de Física, Química e Biologia (Brazil); Pagamisse, A., E-mail: aylton@fct.unesp.br [UNESP – Univ Estadual Paulista, Dep de Matemática e Computação (Brazil); Job, A. E., E-mail: job@fct.unesp.br [UNESP – Univ Estadual Paulista, Dep de Física, Química e Biologia (Brazil)

2014-12-15

This study consolidates multi-level starlet segmentation (MLSS) and multi-level starlet optimal segmentation (MLSOS) techniques for photomicrograph segmentation, based on starlet wavelet detail levels to separate areas of interest in an input image. Several segmentation levels can be obtained using MLSS; after that, Matthews correlation coefficient is used to choose an optimal segmentation level, giving rise to MLSOS. In this paper, MLSOS is employed to estimate the concentration of gold nanoparticles with diameter around 47  nm, reduced on natural rubber membranes. These samples were used for the construction of SERS/SERRS substrates and in the study of the influence of natural rubber membranes with incorporated gold nanoparticles on the physiology of Leishmania braziliensis. Precision, recall, and accuracy are used to evaluate the segmentation performance, and MLSOS presents an accuracy greater than 88 % for this application.

Epoxidação "in situ" aplicada ao látex de borracha natural "In situ" epoxidation of natural rubber latex

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Cristiane K. Santin

2012-01-01

Full Text Available O comportamento da borracha natural na forma látex frente à reação de epoxidação foi avaliado visando estabelecer as melhores condições reacionais sem a ocorrência de reações laterais, que promovem a coagulação do látex e o desenvolvimento de um aglomerado de borracha. Grupos epóxidos foram gerados através da reação de epoxidação a partir da formação in situ do ácido perfórmico. As amostras foram caracterizadas qualitativamente por espectroscopia de infravermelho (FTIR e o grau de modificação determinado por ressonância magnética nuclear de hidrogênio (1H-RMN. Análises de calorimetria exploratória diferencial (DSC demonstraram que a mobilidade da cadeia polimérica foi influenciada pela presença de grupos epóxidos, com aumento linear na temperatura de transição vítrea (Tg. Os resultados indicaram que a epoxidação do látex de borracha natural, sem a ocorrência de reações laterais, é possível e dependente das condições reacionais.Natural rubber latex was submitted to epoxidation reaction to establish the best reaction conditions without the occurrence of side reactions, which promote coagulation of the latex and development of an agglomerate of rubber. Epoxy groups were produced by in situ epoxidation with formic acid and hydrogen peroxide. The samples were characterized qualitatively by Fourier Transform Infrared (FTIR analysis and the degree of modification determined by Hydrogen Nuclear Magnetic Resonance Spectroscopy (1H-NMR analysis. A linear increase in the glass transition temperature (Tg was observed. The results show that the epoxidation of natural rubber latex is possible and depends on the reaction conditions.

Transcript Profiling of Hevea brasiliensis during Latex Flow

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Jinquan Chao

2017-11-01

Full Text Available Latex exploitation enhances latex regeneration in rubber trees. The latex exploitation-caused latex flow lasts from 10 min to a few hours, which is convenient for exploring the transcript profiling of latex metabolism-related genes at the different stages of latex flow. In the present study, the expression pattern of 62 latex metabolism-related genes involved in water transportation, carbohydrate metabolism, natural rubber biosynthesis, hormone signaling, ROS generation and scavenging, and latex coagulum across three stages of latex flow between rubber tree clones CATAS7-33-97 and CATAS8-79 were comparatively analyzed by quantitative real-time PCR. The two clones show differences in latex regeneration and have a different duration of latex flow. The results showed that the expression levels of 38 genes were significantly higher in CATAS8-79 latex than in CATAS7-33-97 during latex regeneration, while 45 genes had a notably higher expression level in CATAS8-79 latex during latex flow. Together with the activation of the MEP pathway and jasmonate pathway in CATAS8-79 latex, HbPIP1;3, HbPIP1;4, HbSUT3, HbSus3, HbHMGS1-2, HbMK should contribute to the high latex regeneration ability. The up-regulation of ethylene signaling and Hb44KD and the down-regulation of latex coagulation-related genes in CATAS8-79 latex might contribute to its longer latex flow duration. This study provides some cues for revealing the regulation of latex metabolism in rubber trees.

Effect of Modified Natural Rubber on PVC-ENR Electrospun Membrane: Thermal and Morphological Studies

International Nuclear Information System (INIS)

Mahathir Mohamed; Dahlan Mohd; Ratnam, C.T.; Pairu Ibrahim

2016-01-01

Electrospun fibers membrane (EFM) based on modified epoxidized natural rubber (ENR) and polyvinyl chloride (PVC) was successfully prepared by electro spinning technique. Epoxidized natural rubber was firstly prepared in solution by using 5 L flask and exposed to high intensity UV lamp for degradation. The PVC/ ENR mixture solution concentration were about 16 wt% and blended for 5 hours for homogeneity. The PVC/ ENR mixture were electro spun to form fibers membrane. The sample of electro spun fibers membrane were cured by electron beam. The resulting membranes were characterized for thermal and morphological studies. Thermal decomposition behavior of EFM was analyzed by thermogravimetric analysis (TGA). Thermo gram from TGA showed two stages of degradation for all formulation (90:10, 80:20, 70:30 PVC/ ENR) from 240 to 265 degree Celsius and 400 to 410 degree Celsius, respectively. From the DSC thermo gram of PVC/ ENR electro spun fibers showed that the addition of ENR resulted in the shifting of glass transition temperature (Tg) towards lower temperatures. The morphology of electro spun fibers was examined using scanning electron microscopy and it showed a variety of fiber morphologies. (author)

Performance of carbon fiber reinforced rubber composite armour against shaped charge jet penetration

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Yue Lian-yong

2016-01-01

Full Text Available Natural rubber is reinforced with carbon fiber; the protective performances of the carbonfiber reinforced rubber composite armour to shaped charge jet have been studied based on the depth of penetration experiments. The craters on the witness blocks, the nature rubber based composite plates’ deformation and the Scanning Electron Microscopy for the hybrid fiber reinforced rubber plate also is analyzed. The results showed that the composite armour can affect the stability of the jet and made part of the jet fracture. The carbon fiber reinforced rubber composite armour has good defence ablity especially when the nature rubber plate hybrid 15% volume percentage carbonfiber and the obliquity angle is 68°. The hybrid fiber reinforced rubber composite armour can be used as a new kind of light protective armour.

Oxidation Degradation Study And Use Of Phenol And Amina Antioxidant Compounds In Natural Rubber Cyclical

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Arofah Megasari Siregar

2015-08-01

Full Text Available The research was conducted research into the use of commercial antioxidants Irganox 1010 wingstay to inhibit the oxidative degradation of cyclic polymers of natural rubber and polypropylene nanocomposite with commercial montmorillonite PP MMT-Clay. Proces mixing nanocomposit PPMMT using commercial compatibiliser PP-g-MA PB3200 made in an internal mixer at a temperature of 180 C for 10 minutes and 65 rpm rotor speed. Hyndered phenol antioxidant effectiveness was analyzed using Fourier Transform Infra Red FTIR. Analysis of infrared is done by measuring the broad index absorption of the carbonyl group CO at a wavelength of 1700 cm-1 and a broad index uptake hydroxyl group at a wavelength of 3400 cm-1 before and after heated in an oven temperature of 125oC with variations in exposure time. The results indicate the use of antioxidant Irganox 1010 in nanocomposite PP MMT with a stabilizing factor of 5.5. Further commercial antioxidants will be used to restrain the rate of oxidation degradation of the natural rubber products cyclical CNR.

Energy efficiency enhancement of natural rubber smoking process by flow improvement using a CFD technique

International Nuclear Information System (INIS)

Tekasakul, Perapong; Promtong, Machimontorn

2008-01-01

A non-uniform flow and large temperature variation in a natural rubber smoking-room cause an inefficient use of energy. Flow uniformity and temperature variation can be improved by using a computational fluid dynamics (CFD) simulation. The effects of the size, position and number of gas supply ducts and ventilating lids which were at the inlets and the outlets of the smoking-room were investigated. The optimal rubber smoking-room of size 2.6 m x 6.2 m x 3.6 m contains 154 50 mm-diameter hot gas supply ducts, and four 0.25 x 0.25 m and four 0.25 x 0.20 m ventilating lids. The velocity distribution of this model in the rubber-hanging area was rather uniform. The average monitoring temperature of 54 positions was 62.1 deg. C. This model could reduce the temperature variation by a factor of three from the original room model, i.e., from 15 to 5.5 deg. C. In a further study, the heat input of an appropriate room model was finely adjusted to obtain a suitable temperature (60 deg. C) for the smoking process. It was found that an appropriate heat supply at this temperature is 11 kW. At this rate, the temperature variation is 5.3 deg. C. This improved model should help the rubber smoking cooperatives to achieve at least a 31.25% saving in energy

Energy efficiency enhancement of natural rubber smoking process by flow improvement using a CFD technique

Energy Technology Data Exchange (ETDEWEB)

Tekasakul, Perapong [Energy Technology Research Center and Department of Mechanical Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand)], E-mail: perapong.t@psu.ac.th; Promtong, Machimontorn [Division of Mechanical Engineering, School of Engineering and Resources, Walailak University, Nakhon Si Thammarat 80160 (Thailand)

2008-09-15

A non-uniform flow and large temperature variation in a natural rubber smoking-room cause an inefficient use of energy. Flow uniformity and temperature variation can be improved by using a computational fluid dynamics (CFD) simulation. The effects of the size, position and number of gas supply ducts and ventilating lids which were at the inlets and the outlets of the smoking-room were investigated. The optimal rubber smoking-room of size 2.6 m x 6.2 m x 3.6 m contains 154 50 mm-diameter hot gas supply ducts, and four 0.25 x 0.25 m and four 0.25 x 0.20 m ventilating lids. The velocity distribution of this model in the rubber-hanging area was rather uniform. The average monitoring temperature of 54 positions was 62.1 deg. C. This model could reduce the temperature variation by a factor of three from the original room model, i.e., from 15 to 5.5 deg. C. In a further study, the heat input of an appropriate room model was finely adjusted to obtain a suitable temperature (60 deg. C) for the smoking process. It was found that an appropriate heat supply at this temperature is 11 kW. At this rate, the temperature variation is 5.3 deg. C. This improved model should help the rubber smoking cooperatives to achieve at least a 31.25% saving in energy.

Effects of variation of oil and zinc oxide type on the gas barrier and mechanical properties of chlorobutyl rubber/epoxidised natural rubber blends

International Nuclear Information System (INIS)

Li, Lin; Zhang, Jin; Jo, Jae Ok; Datta, Sanjoy; Kim, Jin Kuk

2013-01-01

Highlights: ► A (90:10) blend of CIIR and ENR by weight was used as the base. ► Different process oil and ZnO were used to optimize the gas barrier property. ► The minimum oxygen permeability is obtained using sheet ZnO. - Abstract: In many polymer applications such as inner tire liners and fuel hoses, imparting excellent gas barrier property is of prime importance. Researches in this direction had been done based on a judicious choice of polymer type or a blend thereof and the compounding ingredients. Though butyl rubber has been the polymer of choice because of its excellent gas barrier property, yet researches were targeted to improve the same with further modification in the polymer type and variation in compounding ingredients. In this study, a (90:10) blend of chlorobutyl rubber (CIIR) and Epoxdised Natural Rubber (ENR) by weight was used as the base. Four different types of process oil and three different types of zinc oxide (ZnO) at fixed predetermined concentrations were used to optimize the gas barrier and mechanical properties. In this blend, recycled aromatic oil (RAE) and sheet zinc oxide were effective in imparting the best overall combination of properties. Scanning Electron Microscopic (SEM) studies of ZnO were done to understand the structure property relationship

Forest Conversion to Land of Rubber and Palm Oil Farming and Its Effect on Run Off and Soil Erosion in Batang Pelepat Watershed

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Sunarti

2008-09-01

Full Text Available Forest conversion to some land use happened in all watershed, includes Batang Pelepat watershed. The objectives of this research are to know effect of forest conversion to land of rubber (Hevea brasiliensis and palm oil (Elaeis guinensis Jack farming on run off and soil erosion and different of erosion rate on agro technology of rubber and palm oil farming in Batang Pelepat watershed. The research was carried out during 3 months, begin October to December 2006. Run off and soil erosion measured plot with gutter in the lower of plot. Experimental design for this research is randomized complete block design, with land use type as treatment and slope class as replication or block. Data analyzed statistically by variance analysis (F-test and Duncan New Multiple Range Test on confidence 95% (á = 0.05. The results of this research show that area of forest coverage in Batang Pelepat watershed was decreasing. In 1986 this area still 94.50% of watershed area, but in 1994 area of forest only 78.17% and in 2006 forest area 64.20% of watershed area. Forest conversion was carried out to land of rubber and palm oil farming with some actual agro technologies. Land of monoculture rubber I resulted the highest run off and soil erosion more than the other land use type and showed different of run off and soil erosion on land of secondary forest.

PROPERTIES OF NR AND NR/ENR BASED RUBBER COMPOUNDS REINFORCED WITH CHOPPED AND SIZED CARBON FIBER

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Bağdagül Karaağaç

2016-12-01

Full Text Available High elasticity, mechanical resistance and antivibration characteristics of natural rubber (NR are essential issue in the main area of vehicle tyres and high modulus demanding bearing applications. In this study, especially in bearing applications, where natural rubber modulus properties are limited, natural rubber has been reinforced with chopped and hydrocarbon sized carbon fiber to get improved tensile modulus. Besides, epoxidized natural rubber (ENR, which was produced by chemical modification of natural rubber, blended with NR and the compounds have been reinforced with epoxy sized carbon fiber. NR and NR/ENR based rubber compounds’ rheological, mechanical, and aging properties have been systematically investigated and evaluated.

Effect of maleated natural rubber on tensile strength and compatibility of natural rubber/coconut coir composite

Science.gov (United States)

Ujianto, O.; Noviyanti, R.; Wijaya, R.; Ramadhoni, B.

2017-07-01

Natural rubber (NR)/coconut coir (CF) composites were fabricated using co-rotating twin screw extruder with maleated NR (MNR) used as compatibilizer. The MNR was produced at three level of maleic anhydride (MA), and analyzed qualitative and quantitatively using FTIR and titration technique. Analysis on MNR using FTIR and titration methods showed that MA was grafted on NR chain at different percentage (0.76, 2.23, 4.79%) depended on MA concentration. Tensile strength data showed the best tensile strength was produced at 7 phr of MNR with 1 phr of MA level in MNR resulting 16.4 MPa. The improvement of compatibilized samples were more than 300% compare to uncompatibilized composite attributed to better interfacial bonding. The improvement on tensile strength was significantly influenced by MNR level and amount of MA added to produce MNR, as well as their interaction. The optimum conditions for producing NR-CF composite were predicted at 6.5 phr of MNR level with 1 phr of MA concentration added in MNR production, regardless screw rotation settings. Results from verification experiments confirm that developed model was capable of describing phenomena during composite preparation. Morphology analysis using scanning electron microscopy shows smooth covered fiber in compatibilized samples than that of without MNR. The morphology also showed less voids on compatibilized samples attributed to better interfacial bonding leading to tensile strength improvement.

Down-Regulation of Small Rubber Particle Protein Expression Affects Integrity of Rubber Particles and Rubber Content in Taraxacum brevicorniculatum

Czech Academy of Sciences Publication Activity Database

Hillebrand, A.; Post, J. J.; Wurbs, D.; Wahler, D.; Lenders, D.; Krzyžánek, Vladislav; Pruefer, D.; Gronover, CH. S.

2012-01-01

Roč. 7, č. 7 (2012), e41874:1-9 E-ISSN 1932-6203 Institutional support: RVO:68081731 Keywords : Hevea - Brasiliensis * Parthenium-Argentatum * Elongation-Factor * Silencing Affects * Surface-Structure * Oil Bodies * Latex * Prenyltransferase * Biosynthesis * Stability Subject RIV: CE - Biochemistry Impact factor: 3.730, year: 2012

Anatomical Variation in the Wall Thickness of Wood Fibres of ...

African Journals Online (AJOL)

The wall thickness of wood fibres of rubber (Hevea brasiliensis) grown and tapped for latex in south eastern Nigeria were investigated to determine anatomical variation. The rubber trees which were overmature for tapping and keeping were sampled in hierarchical order of plantations, bud classes, trees, discs, cardinal ...

A smart surface from natural rubber: the mechanism of entropic control at the surface monitored by contact angle measurement

Directory of Open Access Journals (Sweden)

Sureurg Khongtong

2006-03-01

Full Text Available Surface oxidation of crosslinked natural rubber provided a hydrophilic substrate (sticky surface that became more hydrophobic (less sticky when equilibrated against hot water. This unusual temperaturedependent surface reconstruction is interpreted as the result of recoiling of entropic unfavorable uncoiled chains induced when rubber surface was oxidized. Subsequent equilibration of these annealed samples against water at room temperature returned their original hydrophilicity. The degree of this surface reconstruction and its kinetics are also dependent on the amounts of crosslinking of the samples.

Preparation and Properties of Biocomposite Based on Natural Rubber and Bagasse Nanocellulose

Directory of Open Access Journals (Sweden)

Jarnthong Methakarn

2015-01-01

Full Text Available Biocomposite based on natural rubber (NR and bagasse nanocellulose (BNC was prepared in latex state. The mechanical, morphological and thermal properties of NR/BNC biocomposite were investigated. It was found that the addition of 3 wt% of BNC in NR film caused significant increase in modulus at 100% and 300% elongations and improved thermal stability of NR/BNC biocomposite. However, the strength at break and elongation at break of the biocomposite were not enhanced correlating to the morphological result obtained from scanning electron microscope (SEM.

Determination of the Mechanical Properties of Rubber by FT-NIR

OpenAIRE

Pornprasit, Rattapol; Pornprasit, Philaiwan; Boonma, Pruet; Natwichai, Juggapong

2016-01-01

Mechanical tests, for example, tensile and hardness tests, are usually used to evaluate the properties of rubber materials. In this work, mechanical properties of selected rubber materials, that is, natural rubber (NR), styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR), and ethylene propylene diene monomer (EPDM), were evaluated using a near infrared (NIR) spectroscopy technique. Here, NR/NBR and NR/EPDM blends were first prepared. All of the samples were then scanned using a FT-...

A Review on Reinforcement of Natural Rubber by Silica Fillers for Use in Low-Rolling Resistance Tires

NARCIS (Netherlands)

Sarkawi, S.S.; Kaewsakul, Wisut; Sahakaro, Kannika; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

2015-01-01

High dispersion silica has recently become the preferred alternative to carbon black for low rolling resistance tyres. However, the combination of natural rubber with silica and a coupling agent remains a challenge, but also offers a tremendous potential for reduction of energy consumption of

Regulamentação pública e conduta das firmas no sistema agroindustrial da borracha natural entre 1997 e 2000 Regulation and behavior of firms in Brazil's natural rubber agro-industrial system between 1997-2000

Directory of Open Access Journals (Sweden)

Augusto Hauber Gamero

2002-01-01

Full Text Available A necessidade de regulamentação no sistema agroindustrial (SAG da borracha natural no Brasil é evidente. Desde a metade do século, quando o país passou a importar esse produto, vários esforços governamentais vêm sendo definidos, objetivando o desenvolvimento sustentável do setor da produção agrícola nacional de borracha. No ano de 1997, criou-se uma política de subvenção direta à produção. Dada a estrutura desse SAG, associada à conjuntura do mercado internacional e a uma regulamentação falha do governo federal, começaram a surgir indícios de abuso de poder de mercado pela indústria pneumática instalada no país, principal consumidora do produto. Utilizando o arcabouço teórico da organização industrial, neste artigo se procurou levantar evidências nesse sentido.The need for regulation of Brazil’s natural rubber agro-industrial system (SAG is evident. Since the middle of the 20th century, when the country began importing rubber, many governmental efforts have been made to promote the sustainable development of Brazil’s natural rubber productive sector. In 1997, the Brazilian government created a direct subvention policy to assist rubber producers. Given the structure of Brazil’s SAG, the international rubber market, and imperfect regulation by the Federal Government, it would not be unexpected to find signs that Brazil’s largest natural rubber consumer, the domestic tire industry, has begun to abusively exercise its market power. Using the theoretical structure of Industrial Organization, this paper tries to show evidences of this abuse.