Core/Clad Phosphate Glass Fibres Containing Iron and/or Titanium

Abstract

Phosphate glasses are novel amorphous biomaterials due to their fully resorbable characteristics, with controllable degradation profiles. In this study, phosphate glasses containing titanium and/or iron were identified to exhibit sufficiently matched thermal properties (glass transition temperature, thermal expansion coefficient and viscosity) which enabled successful co-extrusion of glass billets to form a core/clad preform. The cladding composition for the core/clad preforms were also reversed. Fe clad and Ti clad fibres were successfully drawn with an average diameter of between 30~50 µm. The average cladding annular thickness was estimated to be less than 2 µm. Annealed core/clad fibres were degraded in PBS for a period of 27 days. The strength of the Fe clad fibres appeared to increase from 303 ± 73 MPa to 386 ± 45 MPa after nearly 2 weeks in the dissolution medium (phosphate buffered solution) before decreasing by day 27. The strength of the Ti clad fibres revealed an increase from 236 ± 53 MPa to 295 ± 61 MPa when compared at week 3. The tensile modulus measured for both core/clad fibres ranged between 51 GPa to 60 GPa. During the dissolution study, Fe clad fibres showed a peeling mechanism compared to the Ti clad fibres.

Changes in the mechanical properties of bioactive borophosphate fiber when immersed in aqueous solutions

“…Because the mechanical properties of the fibers remain constant for short immersion in the SBF solution (Figure3C,D), the reactive CaP layer is suspected not to bond to the surface of the fiber, but rather to pill‐off. Similar results were reported for bulk glasses with composition 50P 2 O 5 ‐(40‐x)CaO‐xSrO‐10Na 2 O 49 and with fibers within the metaphosphate composition 50 . However, for long immersion in SBF, the CaP layer is expected to bond to the surface of the fiber leading to a decrease in the mechanical properties of the fibers.…”

“…However, different mechanical properties of the immersed fibers were measured depending on their geometries and designs; smaller increase in the mechanical properties of the (250 µm) fibers as compared to the (125 µm) fibers and faster increase in the mechanical properties of the CC fibers compared to that of the SC fibers were measured after immersion in both solutions. It is well known that the fiber strength is controlled by submicroscopic damage at the surface of the fibers 50‐52 . The fibers with large diameter have large surface area and therefore are more likely to possess a defect with critical size that will govern the overall fibers' mechanical properties 9,53 .…”

The glass formation and crystallization studies on iron phosphate–silicate glasses

“…Extensive research conducted on amorphous phosphate solids indicated their interesting fundamental properties. Various phosphate glasses with appropriate chemical composition were considered to be applicable in laser devices [1][2][3][4], as highly toxic, radioactive waste storage [5][6][7] and hermetic seals [5,8], in electrochemical devices [9], for biomedical usage [10][11][12][13], [8]. Nevertheless, their practical use is limited because of poor chemical durability and difficulties in obtaining glassy material resulted from the tendency to crystallization exhibited during processing [8].…”

Correlation between glass transition effect and structural changes in multicomponent iron phosphate-silicate glasses

“…Iron phosphate glasses present outstanding properties enabling them to be used in various applications [1][2][3][4][5][6][7][8][9][10][11][12][13]. As an example, the great storage capacity of high wastes manifested by traditional iron phosphate glasses characterized by molar composition 60P 2 O 5 -40Fe 2 O 3 may be mentioned [14].…”