Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/101270
Type: Artigo de periódico
Title: Relationship Between Pore Structure And 1h-nmr Relaxation Times In Tio2/poly(dimethylsiloxane) And Caco3/poly(dimethylsiloxane) Composite Powders
Author: Vichi F.M.
Galembeck F.
Halstead T.K.
Williams M.A.K.
Abstract: Titanium(IV) oxide/polydimethylsiloxane (PDMS) and calcium carbonate/PDMS composite powders were obtained by adsorption of the polymer from a chloroform solution onto the inorganic particles followed by a thermal treatment. The composites were characterized by 1H-NMR relaxation and porosimetry. The composites present shorter spin-lattice (T1) and spin-spin (T2) proton relaxation times than silica-reinforced PDMS, and the activation energies for the motions that cause spin-lattice relaxation are 5.8, 4.9, and 0.72 kJ mol-1 for TiO2/PDMS, CaCO3/PDMS, and neat PDMS, respectively, revealing the greater rigidity of the polymer chains within the composite. Spin-spin relaxation (T2) measurements of the composites showed a major component with a shorter T2 and a minor component with a longer T2. The intensity ratio of these two components is very close to the ratio between the amount of polymer that remains between the particles and that penetrating the particle pores as measured by Hg intrusion porosimetry. The shorter T2 component was thus assigned to polymer interspersed among the particles, while the longer T2 component was assigned to polymer within the particle pores.
Editor: John Wiley and Sons Inc., New York, NY, United States
Rights: fechado
Identifier DOI: 
Address: http://www.scopus.com/inward/record.url?eid=2-s2.0-0033469372&partnerID=40&md5=84641cb0e0b1973e8a0fb68202ccdf86
Date Issue: 1999
Appears in Collections:Unicamp - Artigos e Outros Documentos

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