Natural rubber latex used as drug delivery system in guided bone regeneration (GBR)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Metronidazole release using natural rubber latex as matrix

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Use of scrap tire rubber in place of SBS in modified asphalt as an environmentally correct alternative for Brazil

Reusing scrap tires has become a worldwide challenge, especially due to the great difficulty in finding ecologically and economically feasible ways to dispose of them. This has led to the creation of specific programs and legislation for reusing scrap tires. Research has shown that a certain percentage of scrap tire rubber can be added to asphalt compositions, and this has become a worldwide practice. This paper describes the properties of four asphalt compositions modified with scrap tire rubber (STR) prepared in the laboratory. These properties are then compared with those of asphalt modified with styrene butadiene styrene (SBS), a synthetic polymer and one of the most common modifiers, to verify the feasibility of using scrap tire rubber as a substitute for SBS. The scope of this study does not include an analysis of how STR affects end-of-life asphalt. The main findings indicate that STR is a potential substitute of SBS in paving material, and although it does not meet some of the standard specifications when compared with SBS, these issues can be overcome by proper care during storage and transportation. The substitution of SBS by STR also showed the potential for about 10% in expenditure savings. (C) 2012 Elsevier Ltd. All rights reserved.

Structural characterization of wild rubbers, microstructure of the rubber extracted from ficus elastica by C-13-NMR

Low molecular weight fractions of polyisoprene extracted from Ficus elastica Herb. ex Hornem. were studied by C-13-NMR. The identification of 2-3 trans terminal units at the end of the polymer chain needed the acquisition of more than 17 000 transients. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Study of charge transport in blends of natural rubber and poly(o-methoxyaniline) based on a resistor network statistical model

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A comparative study of the non-isothermal degradation of natural rubber from Mangabeira (Hancornia speciosa Gomes) and Seringueira (Hevea brasiliensis)

Due to the increasing search for alternative sources of natural rubber (NR) whose properties are similar to Hevea brasiliesis, several sources have been studied in the past few years. Among them, Mangabeira (Hancornia speciosa Gomes), which is native to Amazon rainforest and other regions of Brazil, has a potential as another viable rubber source. As a continuation of a series of comparative studies between Hancornia and Hevea (clone RRIM 600) these two species by our research team, their thermal behavior was analyzed by thermogravimetry (TG) using Flynn-Wall-Ozawa's approach in order to obtain kinetic parameters (reaction order, pre-exponential factor and activation energy) of the decomposition process. Results indicated that the thermal behavior of NR from Hancornia was comparable to Hevea with some differences observed as follows: reaction order for Hancornia was higher than for Hevea at the beginning of degradation and very close for temperatures over 350 A degrees C; activation energy and pre-exponential factor had the same trend, i.e., increased with increasing degree of conversion remaining almost constant between 20 and 70% and then increasing for higher degrees, although Hevea was slightly more thermally stable than Hancornia. These major influences in the degradation process in the early stage are attributed to differences in non-rubber constituents present in these two species.

Comparative Study on the Technological Properties of Latex and Natural Rubber from Hancornia speciosa Gomes and Hevea brasiliensis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biological cycle of Lorryia formosa (Acari, Tydeidae) on rubber tree leaves: A case of thelytoky

Lorryia formosa Cooreman has been collected on many different host plants around the world. The biological cycle of this species was studied at 28 degrees C with mites collected from a rubber tree crop. The life table was constructed based on sixty individuals. The average lifetime was 37.43 +/- 20.23 (SE) days, and the r(m) was 0.08. The sex ratio was totally female biased, and unfertilized eggs developed into females. This is the first record of thelytoky in Tydeoidea proved by rearing.

Changes in leaf physiology caused by Calacarus heveae (Acari, Eriophyidae) on rubber tree

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Seasonal suitability of three rubber tree clones to Calacarus heveae (Acari, Eriophyidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biological cycle of Tenuipalpus heveae Baker (Acari, Tenuipalpidae) on leaflets of three rubber tree clones

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

NMR study of styrene-butadiene rubber (SBR) and TiO2 nanocomposites

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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

Fungos são os patógenos mais freqüentemente observados em populações de ácaros, auxiliando o controle destes em diferentes culturas. Vinte e cinco amostras de folhas foram coletadas de cultivos de seringueiras vizinhas a dois fragmentos de vegetação de Cerrado. em cada seringal, 25 plantas foram selecionadas para coletas e sete folhas ao redor da copa foram coletadas até a altura de sete a oito metros do solo. Aproximadamente 250 indivíduos de Calacarus heveae Feres, Phyllocoptruta seringueirae Feres e Tenuipalpus heveae Baker, coletados aleatoriamente, foram montados. Hirsutella thompsonii Fisher foi observado nas três espécies de ácaros e T. heveae foi a espécie mais infectada. Os maiores níveis de infecção ocorreram de novembro a fevereiro (estação chuvosa). Na estação seca, os níveis de infecção ficaram abaixo dos 5%. H. thompsonii tem potencial para ser usado como micoacaricida na estação chuvosa.

Review about mites (Acari) of rubber trees (Hevea spp., Euphorbiaceae) in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nutrient cycling in a RRIM 600 clone rubber plantation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)