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Microwave dielectric analysis on porous hydroxyapatite/starch composites with various ratio of hydroxyapatite to starch

2020-07-09 , You B.C. , Cheng Ee Meng , Shahriman Abu Bakar , Nashrul Fazli Mohd Nasir , Eng Swee Kheng , Mohd Shukry Abdul Majid , Mohd Ridzuan Mohd Jamir , Khor Shing Fhan

This study aims to investigate the dielectric response of the porous hydroxyapatite/starch composites by varying the starch proportion in determining the feasibility of the microwave sample characterization technique in bone tissue engineering. The porous hydroxyapatite/starch composites were fabricated by using natural starch (gelatinization and retrogradation) through the solvent casting and particulate leaching technique. The dielectric constant (ϵ′) and loss factor (ϵ″) of the complex permittivity of the porous hydroxyapatite/starch composites were measured in the Ku band frequency of 12.4-18.0 GHz. ϵ′ and ϵ″ of the porous composites increase with frequency. The highly porous composite that due to higher starch proportion exhibit higher ϵ′ and ϵ″, resulting in the significant dielectric responses.

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The Effect of the Amylose/Amylopectin Contents of Starch on Porosity and Dielectric Properties of the Porous Hydroxyapatite/Starch Composites

2020-07-09 , Chong You B. , Cheng Ee Meng , Abu Bakar S. , Nashrul Fazli Mohd Nasir , Eng Swee Kheng , Mohd Shukry Abdul Majid , Mohd Ridzuan Mohd Jamir , Khor Shing Fhan

This study aims to determine the effect of the amylose/amylopectin contents of starch on the porosity and dielectric properties of porous hydroxyapatite/starch composites. The porous hydroxyapatite/starch composites were prepared by utilizing the starches (rice, corn and potato starch) via gelatinization and retrogradation process. The complex permittivity of the porous hydroxyapatite/starch composites were evaluated in the frequency range of 12.4-18.0 GHz. The porous composites were exhibited the higher average porosity by using the starch with higher amylopectin content. The highly porous hydroxyapatite/starch composites with higher amylopectin content show the significant fluctuation peaks (at 13.8 and 16.6 GHz) and the higher imaginary part of the complex permittivity (ϵ′′) at higher frequency in the dielectric spectrum, respectively. The real (ϵ′) and imaginary part (ϵ′′) of the complex permittivity of the porous composites could be enhanced by increasing the average porosity and the amylopectin contents.