CHARACTERIZATION OF THE PHYSICOCHEMICAL AND MECHANICAL PROPERTIES OF A VINYL MALEIC ANHYDRIDE COPOLYMER AND ITS ACID/SALT DERIVATIVES FOR USE AS ORAL BIOADHESIVE MATERIALS
Abstract
The physicochemical and mechanical properties of a poly (methyl vinyl ether/maleic anhydride) copolymer, and its free diacid and salt derivatives were studied. Potentiometric titration, continuous pH-monitoring, infrared spectroscopy, and differential scanning calorimetry (DSC) were employed as methods to determine the chemical compositions of the anhydride/acid PVM/MA copolymer material and/or mixtures of the anhydride, the free diacid, and monobasic salt, and the dibasic salt of the PVM/MA copolymer salt products. In vitro adhesional analyses of the powder and cream forms of the various PVM/MA anhydride/acid/salt compositions were conducted using an Instron stress-strain analyzer and a specially constructed testing appliance. The Instron tester was interfaced with a PDP-11/70 mini-computer system, to facilitate the determination of measurements of the maximum adhesional force, the total adhesional energy, the maximum compressional force, Young's modulus, and various adhesional or compressional strength versus time profiles. These properties were related to the potential values of the polymer products as oral bioadhesive materials in denture stabilization applications. The effects of the polymer product composition, sample preparation, test environment and other factors, on the recorded adhesional properties of the systems were determined. The mechanical/adhesional analyses of various commercial denture adhesives were also undertaken, and the properties of these materials were compared to the experimental polymer products. A continuous pH-monitoring device was developed to continuously record the apparent pH values of the PVM/MA starting copolymer material on dissolution. The observed apparent pH values during dissolution were found to correlate with the free diacid concentrations of the samples analyzed. Dissolution mechanisms were proposed for the dissolution process of the PVM/MA anhydride copolymer, in which three distinct rate periods were observed. The compositions of PVM/MA copolymer mixtures of unknown anhydride/acid/salt contents could also be approximated by evaluating the characteristic pH-time dissolution profiles. Quantitative Infrared analyses were developed to evaluate the acid/anhydride and various salt forms. Infrared analyses were conducted in the solid state with an extrinsic internal standard, in the solid state with an intrinsic internal standard, and in solution in an appropriate organic solvent. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of school.) UMI
Degree
Ph.D.
Subject Area
Pharmaceuticals
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