Fabrication and characterization of novel ternary nanocomposites for load bearing orthopedic implants

Abstract

The mechanical aspects of the load-bearing orthopedic implants are equally important to the biological aspects. The metallic implants have inherent problems and need to replace with polymer-based implants. The present work is an attempt to improve the elastic modulus (E), hardness (H), fracture resistance (E/H), storage modulus (E ), and wettability simultaneously by reinforcing the PEEK matrix with nano-hydroxyapatite (nHA), MWCNTs fillers, and nHA-MWCNTs hybrid fillers. The binary nanocomposites and ternary hybrid nanocomposites of nHA (25, 30, and 35 wt.%), MWCNTs (0,1,3,5, and 7 wt.%), and PEEK were fabricated by Ball Mixing and Compression Molding process. The process parameters were optimized using Taguchi Method. In case of PEEK/nHA binary nanocomposites, the E, H and E were increased newlinewith increasing content of nHA. These properties were also improved with increasing content of MWCNTs up to 5 wt.% of MWCNTs, in case of PEEK/(0-7%)MWCNTs binary nanocomposites and PEEK/nHA-(0-7%)MWCNTs ternary hybrid nanocomposites. However, the mechanical properties were reduced beyond 5 wt.% reinforcement of MWCNTs, most probably due to the enlargement of distance between polymer chains and agglomeration of MWCNTs. The E of PEEK/30%nHA-5%MWCNTs nanocomposite was observed to be 7.67 GPa, which falls within the range of E of the human cortical bone. The water contact angle of the surface of PEEK/nHA nanocomposites was decreased with increasing content of nHA due to increasing content of oxygen on the surface. While in case of PEEK/nHA-(0-7%)MWCNTs hybrid nanocomposites, the contact angle was increased with increasing content of MWCNTs due to presence of hydrophobic carbon atoms with sp2 hybridization. newline newline