THERMAL-BEHAVIOR OF METHYL P-HYDROXYBENZOATE IN CONTROLLED-PORE GLASSSOLID DISPERSION

Citation
E. Yonemochi et al., THERMAL-BEHAVIOR OF METHYL P-HYDROXYBENZOATE IN CONTROLLED-PORE GLASSSOLID DISPERSION, Journal of colloid and interface science, 173(1), 1995, pp. 186-191
Citations number
14
Categorie Soggetti
Chemistry Physical
ISSN journal
00219797
Volume
173
Issue
1
Year of publication
1995
Pages
186 - 191
Database
ISI
SICI code
0021-9797(1995)173:1<186:TOMPIC>2.0.ZU;2-H
Abstract
Physicochemical properties of methyl p-hydroxybenzoate (MPHB) in a mix ture with controlled-pore glass of 120 Angstrom (CPG120) were investig ated by differential scanning calorimetry (DSC), powder X-ray diffract ion measurement, and IR spectroscopy. In the DSC thermogram of a mixtu re of 40% MPHB and 60% CPG120, a broad endothermic peak(108-112 degree s C) and a sharp endothermic peak due to the fusion of MPHB were obser ved. In the following DSC run, the temperature of the endothermic peak (108-112 degrees C) was shifted to a lower temperature( 80-100 degree s C). The effects of grinding and atmospheric gas pressure on the DSC thermograms were also studied, Increase of the grinding time caused a decrease in the DSC peak area of fusion, and the adsorption of MPHB in to the CPG pores was enhanced with grinding. The peak at 108-112 degre es C moved to higher temperatures in the condition of increased gas pr essure. In the second DSC run, the temperature of the endothermic peak depended upon the pore size of the mixed CPG, These results indicated that MPHB in the mixture adsorbed into the pores of the CPG during th e first DSC run and that the adsorbed and crystallized MPHB fused in t he pores in the second run. (C) 1995 Academic Press, Inc.