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
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.