Poster presented at the 8th Conference of Yugoslav Materials Research Society – YUCOMAT 2006, Herceg Novi, Crna Gora, 4-8. septembar 2006

Ignjatović, Nenad

Jevtić, Marija

Mitrić, Miodrag

Uskoković, Dragan

English

Serbian Academy of Science and Arts Digital Archive (DAIS)

SONOCHEMICAL SYNTHESIS OF HYDROXYAPATITE USING HOMOGENIOUS PRECIPITATION AGENT- UREAM. Jevtić1a, M. Mitrić2b, N. Ignjatović1c, D. Uskoković1d1Institute of Technical Sciences of the Serbian Academy of Sciences and Arts, Belgrade, Serbia2The Vinča Institute of Nuclear Sciences, Laboratory for Theoretical and Condensed Matter Physics, Belgrade, SerbiaIntroductionSynthetic hydroxyapatite- HAp is biomaterial with excellent biocompatibility, bioactivity and similarity to live bond. Its mechanical properties allow using this biomaterial for medical and dental applications [1-4].Ultrasonic irradiation is a novel precipitation method for nanocrystalline HAp preparation [5]. The chemical effects of ultrasound derive primarily from acoustic cavitations (the formation, growth and collapse of bubbles) [6] . Synthesis of HAp nanoparticles in ultrason ic precipitation and influence of temperature, [Ca2+], Ca/P ratio and ultrasonic power on its morphology and crystalline has been recently reported by Li-yun, Chuan-bo Zhang and Jian-feng Huang Cao [5,7].In this work we analyzed ability for HAp sinthesing using homogeni ous precipitation method in the field of ultrasonic irradiation. We researched ability of using urea for precipitation agent. We defined basic syntheti c parameters: temperature, concentration, power of ultrasound field, time and dynamics of ultrasound field effect.  Materials and methodsResults and disscusionConclusionReferencesIn the first step, Ca(NO3 )2 and NH4 H2 PO4 were dissolved in distilled water, by stirring on stirrer, to make homogeneous solutions with Ca/P ratio at 2 and [Ca2+] at 0.02M. Solutions were pounded into reaction vessel and heated at 88°C.Next, different volumes of 12% urea were added to regulate pH value and to allow homogeneous precipitation (Table 1). Parameters of ultrasonic liquid processor were set (Table 2). The sonic horn, made of Ti, was dipped into solution  and ultrasonic irradiating started.  Precipitates were aged for 15 h,separated from the mother liquid and washed with distilled water by centrifugal processing method. Sludges were dried in dryer for 5h at 80ºC.Table 1:  Parameters of ultrasonic liquid processorT(˚C) t (min) amp.(%)60-80 2 8080-90 3 8080-90 3 8082-90 3 8080-90 3 85Table 2: Volume of 12% urea in different  samplessample urea (ml)1 1002 153 104 85 66 501234567891025 50 75 85 0 10 20 30 40 50 60 7001002005 ml of urea2θ (°)0 10 20 30 40 50 60 7001002003004006 ml of urea0 10 20 30 40 50 60 700501001502008ml of ureaIntenzitet0 10 20 30 40 50 60 70010020030010 ml of urea4000 3000 2000 1000020406080100TransmissionWavenumber (cm-1)H2 OPO43-PO43-OH-H2 OOH-CO2 airHAp content (%)Urea (ml)Figure 2: IR spectra of HAp monophase Graph 1: Relationship between urea andHAp content Figure 1: XRD spectra of samplesFigure 1 shows XRD of powders synthesized with different amount of precipitation agent. Samples A, B and C consist two phases- HAp and OCP (octa calcium phosphate). OCP is intermediate for HAp synthesis. Sample D is monophase HAp which indicate that reaction is finished. Graph 1 shows increasing of HAp content with increasing of urea amount i.e. concentration of OH- ions according figure 1. Figure 2 represents IR spectrum of sample D. The characteristic bands of HAp are exhibited:632.42 cm-1, 601. 88 cm-1 and 563.88 cm-1 for PO43- bending, 961.76 cm-1, 1108.1 cm-1 and 1032.5 cm-1 for PO43- stretching, 3568.8 cm-1 and 632.43 cm-1 for OH- vibrations. The broad band at 2500-3600 cm-1 and band at 1642.5 cm-1 are reflection of absorbed and associated water in HAp powder.  Bands at 874.93 cm-1 and 1455.1 cm-1 are vibrations of CO32- group which presence is normal concerned with organic precipitation agent. The band at 2359.2 is air CO2 vibration. There are no bands in IR spectrum or peaks in XRD patterns belong to urea or any urea composition. That indicates that urea is totally decomposed.ABCDIn this work we synthesized Hap using sonochemical method. As starting components we used Ca(NO3 )2 , NH4 H2 PO4 ( Ca/P ratio was 2) and homogeneous agent was urea ( NH2 CONH2 ). With following parameters: T= (80-90)˚C, P= 600W, E= 400 kJ and ratio Ca:P:Urea = 2:1:9 we obtained HAp and OCP mixture. With increasing of urea content, HAp percentage increased, too. In the final product we obtained HAp monophase. Optimal parameters were: T= (80-90)˚C, P= 640W, E= 500 kJ and ratio Ca:P:Urea = 2:1:10. Homogeneous precipitation method in the field of ultrasonic irradiation is very effective for monophase HAp synthesis. [1] X. Y. Pang, X. Bao, Cancer Letters, 107 (1996) 11-18[2] K. J. L. Burg, S. Porter, J. F. Kellam, Biomaterials, 21 (2000) 2347-2359[3] A. K. Dash, G.C. Cudworth, Journ. Pharmacol. Toxicol. Methods, 40 (1998) 1-12[4] W. Suchanek, M. Joshimura, Journ. Mater. Res., 13 (1998) 94-117[5] L. Cao, C. Zhang, J. Huang, Ceramics International, 31 (2005) 1041-1044[6] K. S. Suslick, G. J. Price, Annu. Rev. Mater. Sci., 29 (1999) 295-326[7] L. Cao, C. Zhang, J. Huang, Materials Letters, 59 (2005) 1902-1906

Sonochemical Synthesis of Hydroxyapatite Using Homogeneous Precipitation Agent- Urea

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Sonochemical Synthesis of Hydroxyapatite Using Homogeneous Precipitation Agent- Urea

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