Effect of heat-treatment on the bioactivity and mechanical properties of a poly(ε-caprolactone)/silica hybrid containing calcium salt

The effect of heat-treatment temperature on the bioactivity and mechanical properties of a poly(epsilon-caprolactone) (PCL)/silica hybrid was investigated. The hybrid was prepared through a sol-gel method with triethoxysilane end-capped PCL and tetraethyl orthosilicate (TEOS). After gellation, the hybrid was dried at 60 degreesC for 2 days, and then heat-treated at 100, 150, and 200 degreesC for 24 hours, respectively. Their bioactivities and mechanical properties were evaluated using simulated body fluid (SBF) and tensile test, respectively. All the spcimens produced apatite layers within one week in the SBF and there was no noticeable differences among the hybrids except for the occurrence of some surface cracks at the hybrid heat-treated at 200 degreesC. As increasing heat-treatment temperatures, tensile strength and Young's modulus showed maximum values at 150 degreesC and then decreased. This phenomenon was explained in terms of remained content of PCL phase and its molecular weight distribution in the hybrid after the heat-treatment.