AMPHIPHILIC POLYMER-ASSISTED SYNTHESIS OF HYDROXYAPATITE PARTICLES AND THEIR INFLUENCE ON THE RHEOLOGICAL AND MECHANICAL PROPERTIES OF THERMOSENSITIVE HYDROGELS

Abstract

Polymeric composite materials hold promise for versatile advanced applications. Of utmost importance for these applications is incorporating inorganic particles within polymer matrices which lead to multifunctional polymeric composites with desired functions. Specifically, thermosensitive polymeric hydrogels incorporating particle fillers have elicited widespread interest because of promising applications in drug delivery, tissue engineering, and medical devices. Although these materials are frequently discussed in many research fields, there are no decisive conclusions reported in literature, showing how the particle filler affects the rheological and mechanical behaviors of the resulting hydrogels. In this research, hydroxyapatite (HAp) bioceramics with definable morphologies were synthesized in order to reveal their effects on the resulting properties of HAp/polymer composite hydrogels. HAp particles with spherical, sheet-like and rod-like shapes were prepared with assistance by adding amphiphilic surfactant, poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) in synthesis. Thermosensitive composite hydrogels with controllable rheological and mechanical properties were thus developed by incorporating HAp particles into poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PEG-PLGA) hydrogel. Experimental results revealed that the rheological and mechanical properties of the resultant HAp/PEG-PLGA composite hydrogel not only influenced by the added HAp particle amount, but also by the particle morphology and interactions between particles and hydrogels. The findings from this research provide a critical guideline for designing thermosensitive composite hydrogels with required rheological and mechanical properties.