Effects of in situ biomineralization on microstructural and mechanical properties of hydroxyapatite/polyethylene composites

Abstract

ABSTRACT:To improve the mechanical properties of hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ; HAP)/High-density polyethylene (HDPE) composites, the process of in situ biomineralization was used, and its effect on the microstructure and mechanical properties of HAP/HDPE composite was investigated by means of Fourier transform infrared spectroscopy, energy dispersive X-ray analysis, scanning electron microscope, Instron testing machine, and Ceast Impact tester at room temperature. Results show that: (1) the HAP/ HDPE composite prepared by in situ biomineralization has the better mechanical properties. The impact strength and the tensile strength reach 712 J/m and 96 MPa, respectively, which were more than three times higher than those of composites prepared by blending directly. (2) The biomineralized HAP crystals grew onto the HDPE with chemical bond and dispersed in HDPE polymer on the level of nanometer dimension, which provided a greater surface area for bonding with the polymer, accordingly enhancing the interfacial bonding strength. On the other hand, the higher interfacial bonding strength will produce interfacial stress from the contraction of matrix, which can strain-induce the crystallization of matrix to form the extended-chain crystal structure in the area surrounding the filler. As a result, the mechanical properties of composite improved greatly.

Injection-molded porous hydroxyapatite/polyamide-66 scaffold for bone repair and investigations on the experimental conditions

“…The extruded strands were quenched immediately after extrusion in a water bath, then palletized. Before injection, all HA=PA66 composite pellets with different HA content (20,30, and 40 wt%), and AC were dried in vacuum oven at 80 C for 12 h. AC was used by weight of 2.5, 4.0, 6.0, and 8.0% (master batch) relative to the HA=PA66 composite, respectively, then these blends were mixed and injection molded into porous scaffolds.…”

“…Injection molding is one of the widely used plastic processing methods for mass production of complex parts, and has been used to fabricate various dense HA/polymer composite as bone‐analogue materials . The combination of HA and polymer may enable the composite to have the advantages of the two components: (1) improved stiffness and bioactivity and (2) improved impact strength and processability.…”

The role of nanocomposites in bone regeneration

“…One approach is to functionalize the ceramic phase, which increases mechanical properties by improving interfacial bonding between the reinforcement and the matrix. 53,54 The Mikos research group has developed an injectable, biodegradable material by cross-linking poly(propylene fumarate) (PPF) with poly(propylene fumarate)-diacrylate (PPF-DA). [55][56][57] This polymer, which degrades via ester hydrolysis into mostly fumaric acid and propylene glycol, shows promise for bone tissue engineering based on its minimal inflammatory and immunologic response, 55,56 but its mechanical properties are below those for human cortical bone.…”

Prediction of mechanical properties of composites of HDPE/HA/EAA

“…Wang and Bonfield (2001) reported an increase in ductility and tensile strength of AA-grafted high-density polyethylene (HDPE) composites filled with HA. Additionally, Huang et al (2006) promoted HA biomineralization in PE when grafted with AA, improving the mechanical properties of the composite as well.…”