Gels of a-zirconium phosphate (a-ZrP) in water have been prepared by exfoliation of crystalline a-ZrP induced by intercalation–deintercalation of propylamine. Although these gels are X-ray amorphous, their Raman spectra indicate that the a-type layers of the starting material remain essentially unaltered. Replacement of gel water with water miscible organic solvents has allowed the formation of a-ZrP gels in a great variety of solvents, such as alkanols, N,N-dimethylformamide (DMF), 1-methyl-2-pyrrolidone (NMP), acetone, tetrahydrofuran (THF) and even chloroform. Particular attention has been devoted to a-ZrP gels in DMF. On the basis of the surface area of the dry gels, the average thickness of the particles of exfoliated a-ZrP has been estimated between 25 and 80 nm for a-ZrP percentages in the starting gels between 2.5 and 10 wt%, respectively, in agreement with SEM images. a-ZrP gels in THF have been used for the preparation of polystyrene/ a-ZrP nanocomposites with filler loadings up to 8 wt%. The presence of exfoliated a-ZrP delays the beginning of thermal decomposition of the polymer by a maximum of 45 uC for 4 wt% filler loading.The state of filler exfoliation has been confirmed by transmission electron microscopy.
Gels of zirconium phosphate in organic solvents and their use for thepreparation of polymeric nanocomposites
BOTTINO, ALDO;PIAGGIO, PAOLO
2005-01-01
Abstract
Gels of a-zirconium phosphate (a-ZrP) in water have been prepared by exfoliation of crystalline a-ZrP induced by intercalation–deintercalation of propylamine. Although these gels are X-ray amorphous, their Raman spectra indicate that the a-type layers of the starting material remain essentially unaltered. Replacement of gel water with water miscible organic solvents has allowed the formation of a-ZrP gels in a great variety of solvents, such as alkanols, N,N-dimethylformamide (DMF), 1-methyl-2-pyrrolidone (NMP), acetone, tetrahydrofuran (THF) and even chloroform. Particular attention has been devoted to a-ZrP gels in DMF. On the basis of the surface area of the dry gels, the average thickness of the particles of exfoliated a-ZrP has been estimated between 25 and 80 nm for a-ZrP percentages in the starting gels between 2.5 and 10 wt%, respectively, in agreement with SEM images. a-ZrP gels in THF have been used for the preparation of polystyrene/ a-ZrP nanocomposites with filler loadings up to 8 wt%. The presence of exfoliated a-ZrP delays the beginning of thermal decomposition of the polymer by a maximum of 45 uC for 4 wt% filler loading.The state of filler exfoliation has been confirmed by transmission electron microscopy.
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