POLYMERS Syntheti Thermoplastics PTFE ( Teflon Resistance to chemical degradation Low wear resistance Hydrophobicity Hydrophobic Low friction Does not display typical thermoplastic flow behavior UHMWPE Relatively high wear resistance Subject to oxidatio PET (Dacron) Subject to hydrolysis Low MW contaminants PMMA Polymerization in vivo Low fatigue strength ( for load-bearing appl PSF High strength thermoplast Water absorption (dec strength in water) PEEK High strength( PsF) Unproven C/PSF. C/PEEK Very high strength Unproven Relatively low modulus Elastomers PDMS High flex life Low wear resistance Ease of manufacture Release of low Mw PDms Range of mechanical properties Immunogenicity?POLYMERS Synthetic Thermoplastics PTFE (Teflon) Resistance to chemical degradation Low wear resistance Hydrophobicity Hydrophobic Low friction Does not display typical thermoplastic flow behavior UHMWPE Relatively high wear resistance Subject to oxidation PET (Dacron) PMMA Polymerization in vivo PSF High strength thermoplastic PEEK High strength (> PSF) Low water absorption C/PSF; C/PEEK Very high strength Relatively low modulus Elastomers PDMS High flex life Ease of manufacture Subject to hydrolysis Low MW contaminants Low fatigue strength (for load-bearing applications) Water absorption (dec. strength in water) Unproven Unproven Low wear resistance Release of low MW PDMS Range of mechanical properties Immunogenicity?