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Fast Casters – Initial Prototype April 6 th , 2006. Rene Chen Byron Hsu Kimberly Kam Kelsey Vandermeulen Lisa Witmer. Update. Printed new samples Mechanical Testing Tension Compression SEM Analysis Sintering Prototype. Formulations. Variables: particle size of...
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Fast Casters – Initial PrototypeApril 6th, 2006 Rene Chen Byron Hsu Kimberly Kam Kelsey Vandermeulen Lisa Witmer
Update • Printed new samples • Mechanical Testing • Tension • Compression • SEM Analysis • Sintering • Prototype
Formulations • Variables: particle size of... • Fluka TCP vs. MGH TCP • Sucrose vs. 10x Confectioners Powder Sugar
Formulations PCL: polycaprolactone TCP: tricalcium phosphate
New Sample Dimensions • Dog bones for tension test: 5mm x 5mm x 20 mm • Cylinders for Compression test: 15mm x 15mm
Mechanical Testing - Purpose • Mechanical modulus in the range of hard (10–1,500 MPa) or soft tissues (0.4–350 MPa) needed to prevent new tissue failure due to excessive deformation. • Scaffold mechanical properties theoretical maximum set by bulk material Hollister, Scott. Porous scaffold design for tissue engineering. Nature materials. Vol 4. July 2005
Mechanical Testing • 0.05 mm/s pull rate • data collection at 80Hz • Load cell: 10N for tension 2000N for compression
Mechanical Testing - Results BLUE: TCP (Serdy), sucrose RED: TCP (Fluka), 10x confectioner’s sugar BLACK: TCP (Serdy), 10x confectioner’s sugar
Mechanical Testing - Results BLUE: TCP (Serdy), sucrose RED: TCP (Fluka), 10x confectioner’s sugar BLACK: TCP (Serdy), 10x confectioner’s sugar
SEM Analysis - Results SEM Analysis - Results TCP: Ca5(PO4)3OH
SEM Analysis - Results SEM Analysis - Results Ca5(PO4)3OH + Polymer
SEM Analysis - Results Necking in polymer matrix
Sintering • Purpose: create a stiffer porous structure • Polymer is too soft • Increase TCP concentration • Idea: sinter a TCP + polymer/sugar mixture to create porosity with strength
Sintering Techniques • Densification • Higher temperature • Center approach each other (Shrinkage) • Coarsening • Lower temperature • High Strength + Porosity maintained!
Initial Prototype Formulation • Smaller particles weaker structure • Sintering • Higher volume percent TCP • Experiment with heating times and rates