Affiliations: School of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham, UK
Note: [] Address for correspondence: Dr. Aziza Mahomed, School of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK. Tel.: +44 121 414 7229; Fax: +44 121 414 3958; E-mail: [email protected]
Abstract: Four samples of four medical grade silicones were swollen in six “good” liquids (i.e. those with a good swelling ability, in which silicones swell appreciably) at 25°C, until they reached constant mass (i.e. equilibrium). The volume fraction, ϕ, of the silicone in the swollen sample was calculated for each grade of silicone. Using a combination of the six ϕ values obtained in this study and four of those obtained in a previous study, for each silicone grade, ϕ was plotted against δl, the liquid solubility parameter for the ten liquids used. Using a curve fitting technique a second-order polynomial was plotted through the data points; the minimum in this polynomial provided a value for δp (the polymer solubility parameter). Furthermore, the results showed that the δp values obtained in this study (using ten liquids) were slightly but significantly greater (p<0.05) than those obtained in a previous study (using four liquids), for grade C6-165 only. Similarly, the χ and υ values obtained in the two studies were only significantly different (p<0.05) from each other, for grade C6-165.
