Kinetics of anhydride formation in xerogels of poly(acrylic acid).
The aim of this work was to study the cross-linkage of xerogels made of Carbopol of different molecular weight (polymers deriving from polyacrylic acid), and the influence exerted by different percentages of beta-cyclodextrin upon the cross-linkage percentage. Xerogels were obtained by high-pressure compression and cross-linking was studied by measuring the weight loss of different formulations over a temperature range of 70 to 190 degrees C. Kinetics of anhydride formation were found to follow a second-order mechanism with an activation energy of approximately 25 kcal mol-1.
Blanco-Fuente
H
H
Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Santiago de Compostela, Spain.
Anguiano-Igea
S
S
Otero-Espinar
F J
FJ
Blanco-Méndez
J
J
D000180:Acrylic Resins / Q000737:chemistry*; D000812:Anhydrides / Q000138:chemical synthesis; D002152:Calorimetry, Differential Scanning; D003432:Cross-Linking Reagents / Q000737:chemistry; D003505:Cyclodextrins / Q000032:analysis / Q000737:chemistry; D004337:Drug Carriers / Q000138:chemical synthesis*; D005782:Gels / Q000138:chemical synthesis*; D007700:Kinetics; D008433:Mathematics; D008970:Molecular Weight; D011145:Polyvinyls / Q000138:chemical synthesis*; D047392:beta-Cyclodextrins
D000180:Acrylic Resins; D000812:Anhydrides; D003432:Cross-Linking Reagents; D003505:Cyclodextrins; D004337:Drug Carriers; D005782:Gels; D011145:Polyvinyls; D047392:beta-Cyclodextrins; C006912:carboxypolymethylene; C006903:carbopol 940; C031215:betadex