Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/196291
Type: Artigo de periódico
Title: Formation Of Calcium Crystallites In Dry Natural Rubber Particles.
Author: Rippel, Márcia M
Leite, Carlos A P
Lee, Lay-Theng
Galembeck, Fernando
Abstract: In this paper, the effects of drying and aging of natural rubber particles of Hevea brasiliensis are studied. The evolutions of the particle morphology and of the elemental distribution are investigated using electron-energy-loss spectroscopy imaging in a low-energy transmission electron microscope (ESI-TEM). It is found that when the sample is aged, calcium salt crystallites are formed around the particles. Fusion of these crystallites with time to form larger crystals shows evidence of ion mobility in the dry rubber matrix. Electron diffraction patterns and elemental mapping analysis indicate the crystals to be calcium sulfate. These crystallites are closely associated with membrane materials of the rubber particle and are surprisingly compatible with the hydrocarbon matrix of the rubber particle. It is proposed that polar sites on the membrane materials provide nucleation sites for the crystallization of calcium and sulfate ions from the latex serum.
Subject: Ammonia
Calcium Compounds
Crystallization
Hevea
Microscopy, Atomic Force
Microscopy, Electron, Transmission
Particle Size
Rubber
Sensitivity And Specificity
Spectrometry, Mass, Electrospray Ionization
Rights: fechado
Identifier DOI: 10.1016/j.jcis.2005.03.014
Address: http://www.ncbi.nlm.nih.gov/pubmed/15927612
Date Issue: 2005
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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