01647naa a2200157 a 450000100080000000500110000800800410001910000170006024500470007726000090012452011260013365000130125965300110127270000220128377301840130510288892005-03-23       2003    bl ---       0--  u    #d1 aFERREIRA, M.  aNanoindentation studies of natural rubber.  c2003  aIn recent years, the importance of natural rubber has increased due to the need for environrnentally friendly materiais and improved properties relative to synthetic materiais. In this context, Embrapa Agricultural Instrumentation, in collaboration with Agronomic Institute of Campinas, has initiated a research program to study the mechanical, chemical, and physical properties and to assess the quality of the natural rubber in São Paulo State, which is the largest rubber producer in Brazil. As one component of this program, the technique of nanoindentation has been employed to characterize the compressive normal load versus displacement properties of natural rubber in nrn thick films yielding information on nanomechanical properties such as viscoelasticity and energy of dissipation. The nanoindentation force curves show forces near to 50 nrn and displacements up to 500 nrn and reveal a huge amount of mechanical hysteresis indicating viscoelastic deformation. This novel technique has great potential to yield insights into the molecular origins of macroscopic mechanical properties and material performance.  aBorracha  aFilmes1 aMATTOSO, L. H. C.  tIn: ENCONTRO DA SOCIEDADE BRASILEIRA DE PESQUISA EM MATERIAIS, SBPMAT, 2., out. 2003., Rio de Janeiro, RJ. Programa e Livro de resumos... Rio de Janeiro: SBPMat, 2003. Ref. A-P10.