Ekachai Hoonnivathana

Characterization of Apatite from Human Teeth via XRD, FT-IR and TGA Techniques

Human teeth (HT) are natural composites which consist of nanohydroxyapatite (HAp) arranged in lamellae and bound to collagen. In present study, prepared HT powders with different ages were characterized by X-Ray Diffraction (XRD), Fourier transform infrared (FT-IR) and thermogravimetric anlysis (TGA) techniques. HT at age ranges of 1-10, 11-20, 21-30, 31-40, 41-50 and 51-60 years old were selected for tests. To prepare samples, human teeth were washed in boiling water for 1 h and left in 1 M KOH solution for 6 h to remove any organic material. After HT samples were cleaned with ultrasonic in ethanol, they were then finely grounded using agate mortar. The results from XRD indicate that the major diffraction peaks of all samples with different ages were very closely identified to that of stoichiometric HAp. All HT powders were found to be nanocrystalline structure. Furthermore, it was found that the decrease in HAp crystallinity seem to increase with higher age of 31-40 years old. To investigate chemical structure confirmed by FT-IR, All HT powders showed the band positions and function groups, which are similar to that of HAp. group found in chemical structure indicates the structure of carbonated apatite. TGA results were found that the increase of weight loss seem to increase with higher age.

Effect of Fish Scales Gelatin and Mixing Ratio on Chemical and Mechanical Characteristics of Gelatin/Chitosan Films

The objective of this work was to compare the chemical properties and mechanical properties (strength and elongation) of gelatin/chitosan (G/Ch) films. The effect of several fish scales such as white perch, java barb, red tilapia and nile tilapia scales and mixing ratios of G/Ch composite was investigated. Several fish scales were cleaned and treated with 1.0 M NaOH and 0.8 M acetic acid at room temperature for 120 min to remove fat. Gelatins were extracted from fish scales using the distilled water at 70°C for 120 min. Chitosan solution was prepared with 1% (w/v) chitosan in 1% (v/v) acetic acid, stirred at room temperature. After that, the G/Ch films were prepared by mixing the fish scale gelatins and chitosan with different ratios and then dried at 70°C. The results showed that the FT-IR of G/Ch films revealed the function groups of both gelatin and chitosan. The gelatin films showed peaks amide A (3219-3315 cm-1), alkane (2930-2958 cm1, 1400 -1479 cm-1and 675-1000 cm-1), amide I (1630-1655 cm-1), amide II (1520-1560 cm-1), amide III (1220-1335 cm-1), and ether (1020-1035 cm-1). The chitosan films showed peaks amide II (1559 cm-1), alkane (1404 cm-1) and ether (1022 cm-1). The tensile strength results of G/Ch films increased and elongation of G/Ch films decreased with increasing the amount of chitosan.

Synthesis of Nanocrystalline β-Tricalcium Phosphate from Chicken Eggshells by Precipitation Method

Nanocrystalline β-TCP was successfully synthesized by simple precipitation method using calcium nitrate obtained eggshell as the calcium source, ammonium phosphate as the phosphate source and ammonia solution as agents for pH adjustment via our synthesis condition. Also, the effect of calcination temperature in range of 200-1200°C on phase transformation was investigated. The synthesized powders were characterized by X-Ray Diffraction (XRD), Rietveld refinements and Fourier transform infrared (FT-IR) techniques. The results indicate that β-TCP was observed at the calcination temperature of 700 °C and above. Furthermore, their crystallinity and crystalline size increase with increasing temperature. The a/c ratio of lattice parameter at temperature of 700-1200°C is similar to the standard phase of β-TCP. The chemical structure confirmed via FT-IR showed the band positions and functional groups, which are similar to that of stoichiometric β-TCP. Finally, eggshells are the potential material for synthesizing nanostructured BCP and may be possible in a low-cost production.

Studying the Effect of ZrO2 Addition on Hydroxyapatite via Ball Milling Technique

The bio-composited ceramic stabilized zirconia-hydroxyapatite had been formed by ball milling method. The hydroxyapatite was synthesized from chicken eggshell via chemical precipitation. And it was mixed with stabilized zirconia powder together. All of the samples had been investigated by XRD, FTIR and UTM tester. The XRD and FTIR result showed that the stabilized zirconia-hydroxyapatite sample powder after ball mill was found only hydroxyapatite and zirconia phase without addition of other phase. High crystallinity of hydroxyapatite can be found after heat treatment and calcium zirconium oxide was formed around 1300 °C. In addition, the compressive strength increased with increasing the zirconia content shown by UTM tester.

Characterization of Chitin Extracted from Waste Sources via XRD, FTIR, and TGA Techniques

This work presents the chitin preparation from waste sources, the chitin powders were successfully extracted from shrimp shell, crab shell and squid pen. To prepare chitin powders, all raw materials were washed and grounded using agate mortar, which the particle size of powder is 212–250 μm. Then, the powdered materials were immersed into solution of chloroform and methanol (with 2:1 ratio) at room temperature for removing fat. The deprotienation and decarbonation, the samples were immersed in 50 wt% of NaOH solution for 24 h and in 4 wt% of HCl for 1 h, respectively. The XRD, FT-IR and TGA techniques were used to indicate the different characteristic between α-chitin and β-chitin prepare.

Performance Study of Humidity Adsorbent Prepared from Waste Shells

CaO samples prepared from calcining the powdered waste shells at 1300°C for 4 h were tested the efficiency of humidity adsorption. The samples were characterized via X-ray diffraction (XRD) and Fourier transform infrared analysis (FT–IR) to identify the characteristic of CaO after humidity adsorption test. The results indicate that duck eggshells are highest capable of humidity adsorption while hydration rate of chicken eggshells is rather equal to that of cockle shells, and lowest hydration rate was found with sample prepared from Mussel shells. Therefore, we can conclude that the waste shells are suitable to be use as humidity adsorbent for commercial in the future

Synthesis and Phase Transformation of Calcium Phosphate Prepared from Chicken Eggshells and Ammonium Phosphate

Material that shows hydroxyapatite and β-tricalcium phosphate phases is called biphasic calcium phosphate (BCP). In present work, biphasic calcium phosphate was prepared and characterized for future applications on the utilization of bioactivity of HAp and resorbability of β-TCP properties. It was simply synthesized by precipitation method using eggshell as the calcium source (Ca) in the form of calcium nitrate and ammonium phosphate as the phosphate source (P) to obtain biphasic calcium phosphate. The prepared BCP powders and crystal structure were characterized by X-ray diffraction (XRD), Rietveld refinements and Fourier transform infrared (FT–IR) techniques. The results indicate that BCP was observed at the calcining temperature of 800 oC and above. Furthermore, the crystallinity of BCP increases with increasing temperature from 800 - 1200 oC. The phase fraction of β-TCP is enhanced with pH of a solution from 8.6-10.6 and decrease with the temperature range of 800 - 1200 oC. The formation of BCP arises from its non-stoichiometric composition of materials such as variation of synthesis parameters.

Synthesis of Coil-Like Shape CNTs by Thermal CVD Method

The coil-like shape carbon nanotubes (CNTs) were synthesized on stainless steel substrates using acetylene gas (C2H2) at 750oC under pressure of 4110−× bar by thermal chemical vapor deposition (CVD) method. The formation of catalytic nanoparticles used hydrogen (H2) as the environment gas. The scanning electron microscope (SEM) image shown the average coil diameter of CNTs is 0.8µm and 0.1 nm for the average coil pitch of CNTs. The Raman spectrum shown the defect of CNTs and indicate that the carbon samples were tubes.

Structural and Optical Study of Nano-Structured CdS-CBD Thin Films on CdTe Substrates Grown by Various Temperatures Deposited

Cadmium sulphide (CdS) thin films have been deposited by chemical bath deposition method (CBD) on CdTe substrates. The temperature of the deposition was varied from 40 oC to 70oC under stirring, pH of complexing agent about 10-11.5 and doping by CdCl2. The morphology was composed of small columnar crystals, characterized by SEM. The crystallographic structure contains a mixture of hexagonal and cubic structures were study by TEM. The energy gap values 2.395 eV were found calculated by reflectance spectra using UV-VIS spectrometer. This study showed the correlation of deposition temperature, grain size, energy gap and observed some properties of CdS nanocrystal in the films.