Real-time dissolution measurement of sized and unsized calcium phosphate glass fibers

The objective of this study was to develop an efficient "real time" measure ment system able to directly measure, with microgram resolution, the dissol ution rate of absorbable glass fibers, and utilize the system to evaluate t he effectiveness of silane-based sizing as a means to delay the fiber disso lution process. The absorbable glass fiber used was calcium phosphate (CaP) , with tetramethoxysilane selected as the sizing agent, E-glass fiber was u sed as a relatively nondegrading control. Both the unsized-CaP and sized-Ca P degraded linearly at both the 37 degrees C and 60 degrees C test temperat ure levels used. No significant decrease in weight-loss rate was recorded w hen the CaP fiber tows were pretreated, using conventional application meth ods, with the tetramethoxysilane sizing for either temperature condition. T he unsized-CaP and sized-CaP weight loss rates were each significantly high er at 60 than at 37 degrees C (both p < 0.02), as expected from dissolution kinetics, Zn terms of actual weight loss rate measured using our system fo r phosphate glass fiber, the unsized-CaP fiber we studied dissolved at a ra te of 10.90 x 10(-09) and 41.20 x 10(-09) g/min-cm(2) at 37 degrees C and 6 0 degrees C, respectively, Considering performance validation of the develo ped system, the slope of the weight loss vs. time plot for the tested E-gla ss fiber was not significantly different compared to a slope equal to zero for both test temperatures. (C) 1999 John Wiley & Sons, Inc.