Natural rubber rheological characterization of rubber tree (Hevea ssp.)new clones recommended for plantation in São Paulo State, Brazil

• Grant number: 08/05568-7
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: October 01, 2009
• End date: November 30, 2010
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Luiz Henrique Capparelli Mattoso
• Grantee: Cybele Lotti
• Host Institution: Embrapa Instrumentação Agropecuária. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA). Ministério da Agricultura, Pecuária e Abastecimento (Brasil). São Carlos , SP, Brazil

Abstract

The raw natural rubber can show great differences in its physical and mechanical properties depending on the presented morphology, which varies with the clone origin, the environmental conditions, the latex processing, to mention a few. Due to its high molecular weight and wide molecular weight distribution, 93-98% of the natural rubber chains are estimated to have branches.Traditionally, the natural rubber rheological behavior has been characterized by Mooney viscosity and Wallace plasticity, in order to classify and to measure the quality and processability of different natural rubber grades in a rapid and practical way. Nevertheless, these methods are not as much as necessary to differentiate and characterize natural rubber clones efficiently. Nowadays, there is a huge tendency of tire industry to the use of the dynamic rheological properties for clone characterization and quality control.The dynamic rheological properties, like G' (storage modulus) and G'' (loss modulus), the steady state properties, like the shear viscosity and the die swell, the creep behavior, Jso, the elongational flow properties, like melt strength and elongational viscosity, are all influenced, in a major or minor degree, by the molecular characteristics, like molecular weight, molecular weight distribution and branching degree.The objective of this project is the dynamic and permanent rheological characterization, under shear and elongational flow, of IAC300 clones series, which are being evaluated in the Fapesp project number 05/45608-3, by Dr. Rogerio Manoel Biagi Moreno. The aim is to obtain molecular characteristics and processability information still not available for these IAC300 clones series. This project will provide important scientific and technological contributions, in cooperation with the IAC genetic improvement program, on the definition of the clones recommended for plantation in the State of Sao Paulo, Brazil. Further, it will be proposed new clones characterization criteria for the Brazilian rubber industry, contributing to the improvement of rubber quality, with reference to its molecular structure and processability. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

LOTTI, CYBELE; MORENO, ROGERIO M. B.; GONCALVES, PAULO DE S.; BHATTACHARYA, SATINATH; MATTOSO, LUIZ H. C.. Extensional rheology of raw natural rubber from new clones of Hevea brasiliensis. POLYMER ENGINEERING AND SCIENCE, v. 52, n. 1, p. 139-148, JAN 2012. (08/05568-7)