Dissertations / Theses on the topic 'Hydroxyapatite Mechanical properties'
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Basar, Burcin. "Structural, Mechanical, And Biocompatibility Investigations Of Yttrium And Fluoride Doped Nano Hydroxyapatite." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610331/index.pdf.
Full textПогорєлов, Максим Володимирович, Максим Владимирович Погорелов, Maksym Volodymyrovych Pohorielov, Віталій Зіновійович Сікора, Виталий Зиновьевич Сикора, Vitalii Zinoviiovych Sikora, O. V. Kalinkevich, S. N. Danilchenko, and V. N. Deyneka. "Bone mechanical properties with chitosan-hydroxyapatite composite implants: a rat model." Thesis, Видавництво СумДУ, 2012. http://essuir.sumdu.edu.ua/handle/123456789/27502.
Full textWong, Siu Ming. "Relationships between microstructure and mechanical properties of PLA/HA system /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?BIEN%202004%20WONG.
Full textKim, Hyunbin. "Synthesis and control of microstructure, mechanical properties, and bioactivity in biphasic and preferentially oriented calcium phosphate bioceramics." Birmingham, Ala. : University of Alabama at Birmingham, 2007. http://www.mhsl.uab.edu/dt/2007p/kim.pdf.
Full textTowler, Mark Robert. "Processing characterisation and mechanical properties of hydroxyapatite-zirconia composites for skeletal implants." Thesis, Queen Mary, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285169.
Full textTyagi, Parul. "Study of nano-mechanical properties of 3D scaffolds prepared from polycaprolactone and hydroxyapatite." Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2007m/tyagi.pdf.
Full textGill, Puneet Kamal S. "Assessment of Biodegradable Magnesium Alloys for Enhanced Mechanical and Biocompatible Properties." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/714.
Full textVakifahmetoglu, Cekdar. "Production And Properties Of Glass Bonded Apatite-wollastonite Bioceramics." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12605852/index.pdf.
Full textHAP) and pseudowollastonite was sintered in the presence of a liquid phase. Three distinct fluxing agents, magnesium flux (MCAS), sodium feldspar and sodium frit (NCAS), were prepared to act as additives for generating the liquid phase during sintering. Among those, the use of sodium frit resulted in the expected bimodal microstructural assembly. During the sintering studies, it was discovered that the apatite component of the ceramic was prone to compositional modifications by reaction with the liquid phase. This interaction resulted in a formation of siliconized HAP which crystallized in the form of rod-like grains. Meanwhile wollastonite grains tended to exhibit faceted equiaxed morphology and bonded to rod-like apatite grains with the help of a glassy phase. The results showed significant enhancement in the mechanical properties of apatite-wollastonite composites compared to phase pure hydroxyapatite. For example, the sample with 47.5 wt% Si-HAP2 + 47.5 wt% W + 5 wt% NCASfrit had the highest value of flexural strength, 83.6 MPa, which was almost twice that of hydroxyapatite, 46.3 MPa. The results for other properties such as compressive strength, hardness and fracture toughness also demonstrated the benefit of apatite-wollastonite composite approach.
Parakala, Padmaja. "Synthesis and characterisation of bulk and thin films of hydroxyapatite." Thesis, Queensland University of Technology, 2002.
Find full textUswatta, Suren Perera. "Injectable Particles for Craniofacial Bone Regeneration." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1481305175641452.
Full textCasas, Luna Mariano. "Struktura a vlastnosti kompozitů na bázi hydroxyapatitu a hořčíku, připravovaných metodou proudem asistované slinovací infiltrace." Doctoral thesis, Vysoké učení technické v Brně. CEITEC VUT, 2020. http://www.nusl.cz/ntk/nusl-432909.
Full textKopuletá, Ema. "Struktura a vlastnosti nanokompozitních sítí kolagen/HAP." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-233390.
Full textOliveira, Fernando Perotta de. "INFLUÊNCIA DO PROCESSAMENTO NA OBTENÇÃO DE BIOCERÂMICAS À BASE DE HIDROXIAPATITA." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2008. http://tede2.uepg.br/jspui/handle/prefix/2067.
Full textCalcium phosphate ceramics have been intensely investigated as bone implant material, amongst them hydroxyapatite (HAP) outstands, which has been widely used in medicine and dentistry for presenting excellent biocompatibility. Due to its chemical similarity to the bone mineral phase, it establishes chemical liaisons with the host tissue, helps in the bone growth and allows cell proliferation. However, its use is limited for presenting poor mechanical resistance. Alternatives to overcome such limitations consist of changing the synthesis route or the composite material preparation. Recently, the hydroxyapatite synthesis in the presence of collagen has been explored, however due to problems related to cost, availability and commercial origin; the collagen was substituted by commercial gelatin in this experiment. Four processing routes, involving the precipitation method were evaluated: hydroxyapatite, with, and without gelatin, powder drying process in oven and through liofilization. X-ray fluorescence results indicate that the Ca/P molar ratio of obtained materials is lower than 1,67; IR analyses suggest the formation of calcium deficient carbonated apatite from the samples without thermal treatment and for the ones thermally treated up to 700ºC. DRX analysis confirms the biphasic ceramic formation, in the presence of β-TCP as a secondary phase, after sintering at 1200ºC. The ratio between TCP/HAP phases of samples thermally treated at 1200ºC increased with the decrease of precursor powder Ca/P molar ratio. Results of diffractograms refinement through the Rietveld Method indicated that samples synthesized in the presence of gelatin presented the lowest β-TCP percentage after sintering at 1200ºC. Particle size distribution analysis indicated that the gelatin presence led to formation of clusters of smaller average diameter. It is believed that its presence be related to changes in the nucleation process and grain growth. For mechanical evaluation, samples were prepared through uniaxial pressing followed by cold isostatic with 200MPa compaction pressure and sintered at 1200ºC for two hours in oxidant atmosphere. It was observed that the presence of gelatin enhanced densification and resulted in higher hardness for the compacts. The facture surface microstructure revealed lower porosity for samples synthesized in the presence of gelatin compared to conventional samples and for the liofilized samples compared to the ones dried in oven. Regarding resistance to bending, values obtained are comparable to the cortical bone, being the highest value obtained from the conventional liofilized hydroxyapatite sample.
Cerâmicas de fosfato de cálcio têm sido intensamente investigadas como material para implantes ósseos. Dentre elas destaca-se principalmente a hidroxiapatita (HAP), amplamente usada nas áreas médica e odontológica por apresentar excelente biocompatibilidade. Devido à similaridade química com a fase mineral do osso, estabelece ligações químicas com o tecido hospedeiro, favorece o crescimento ósseo e permite a proliferação de células. Entretanto, sua utilização é limitada, por apresentar baixa resistência mecânica. As alternativas para superar tal limitação consistem em modificar as rotas de síntese ou a preparação de materiais compósitos. Recentemente, a síntese de hidroxiapatita em presença de colágeno tem se destacado, porém, devido a problemas associados ao custo, disponibilidade e procedência comercial, substituiu-se neste trabalho o colágeno por gelatina comercial. Quatro rotas de processamento envolvendo o método de precipitação foram avaliadas: hidroxiapatita com, e sem gelatina, processo de secagem do pó em estufa e por liofilização. Os resultados de fluorescência de raios X indicam que a razão molar Ca/P dos materiais obtidos é menor que 1,67; as análises de IV sugerem a formação de uma apatita carbonatada deficiente em cálcio para as amostras sem tratamento térmico e para aquelas tratadas termicamente até 700ºC. A análise de DRX confirma a formação de cerâmica bifásica, com presença de β-TCP como fase secundária, após sinterização a 1200ºC. A razão entre as fases TCP/HAP das amostras após tratamento térmico a 1200ºC aumentou com a diminuição da razão molar Ca/P do pó precursor. Os resultados do refinamento dos difratogramas pelo método de Rietveld indicaram que as amostras sintetizadas em presença de gelatina apresentaram após sinterização a 1200ºC os menores percentuais de β-TCP. A análise de distribuição de tamanho de partícula indicou que a presença da gelatina induziu a formação de aglomerados de menor diâmetro médio. Acredita-se que sua presença esteja relacionada a mudanças nos processos de nucleação e crescimento dos grãos. Para avaliação mecânica, foram preparados corpos de prova por prensagem uniaxial seguida de isostática a frio com pressão de compactação de 200 MPa e sinterizados a 1200ºC por 2h em atmosfera oxidante. Verificou-se que a presença de gelatina auxiliou a densificação e resultou em maior dureza para os compactos. A microestrutura da superfície de fratura revelou menor porosidade para as amostras sintetizadas na presença de gelatina em comparação à amostra convencional e para as amostras liofilizadas comparadas àquelas com secagem em estufa. No que se refere aos valores de resistência à flexão, os valores obtidos são comparáveis aos do osso cortical, sendo o maior valor obtido para a amostra de hidroxiapatita convencional liofilizada.
Jaramillo, Isaza Sebastián. "Characterization of the mechanical and morphological properties of cortical bones by nanoindentation and Atomic Force Microscopy." Thesis, Compiègne, 2014. http://www.theses.fr/2014COMP2150/document.
Full textBone is a dynamical, anisotropic, hierarchical, inhomogeneous and time-dependent biological material. At the micro and nano scales, their mechanical and structural characterizations are still being a challenging topic. Nanoindentation and Atomic Force Microscopy are used to assess the mechanical and morphological characteristics of cortical bones. Time-dependent, elastic and plastic mechanical properties were computed using the nanoindentation method proposed by (Mazeran et al., 2012). Experiments were performed on different species of bones for different conditions. Wistar rat femoral cortical bone was used to assess the evolution of the mechanical properties in a life span model (from growth to senescence). The variation of the mechanical properties with age was evidenced and their correlation with physico-chemical properties was established. Then, prediction equations were proposed to describe these behaviours. From these equations, it is possible to estimate an apparent maturation age for each mechanical property. Our findings suggest maturation age is earlier and growth rate are higher for elastic properties than for time-dependent mechanical properties. Time-dependent mechanical behaviour of Human femoral cortical bones were assessed considering its heterogeneity. Haversian systems with different apparent mineral content were identified by means of their apparent grey levels obtained from ESEM images. Results prove the mechanical heterogeneity of the Haversian systems and highlight the influence of the time-dependent mechanical properties in the anisotropic behaviour of bone. Bovine femoral cortical bone was used to quantify the mechanical and morphological effects of the demineralization process. Bone seems to have a quasi-isotropic mechanical behaviour after mineral loss. AFM images of the remaining organic components show that collagen fibrils are oriented in a possible privileged direction. According to our knowledge, few investigations have been performed simultaneously on mechanical, morphological and physico-chemical properties of bone. All these results provide a better understanding of the interactions of the collagen-mineral matrix, bone remodelling and their influence especially in the time-dependent mechanical response. Data reported in this work could be useful to develop and to improve multi-scale bone models and multi-scale constitutive laws for cortical bone
Hamandi, Farah Mohammed Ridha Abdulateef. "Hierarchical Structure, Properties and Bone Mechanics at Macro, Micro, and Nano Levels." Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1607294294076853.
Full textDespang, Florian. "Hydroxylapatit-Verbundwerkstoffe und -Biokeramiken mit parallel orientierten Porenkanälen für das Tissue Engineering von Knochen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-116658.
Full textÅkerlund, Elin. "Development of polymer based composite filaments for 3D printing." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388554.
Full textHuang, Yu-Rung, and 黃于容. "The Mechanical Properties of Hydroxyapatite / Au wires Composites." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/74566192489528879977.
Full text國立臺灣大學
材料科學與工程學研究所
93
Hydroxyapatite (HA) is the bio-compatible material for surgical implants, at present, due to the major mineral constituents of it are similar to animals frames. Although the technique to synthesize HA has been developed for a long period, synthetic HA is still limited by its poor mechanical properties. In the present study, we have prepared two HA matrixes with different particle size and doping gold wire as the toughened phase in hydroxyapatite((Ca10(PO4)6(OH)2, HA) matrix which was synthesized by solid-state synthesis to form ceramic composite reinforcement and to expect the possible strategies to improve the toughness of HA are proposed. Solid-state synthesis was used to prepare the hydroxyapatute, and get two different size HA powder by ball milling and attrition mill methods. The different vatio of Au wire then add entered in two kinds of HA matrix that with different particle size. These composites undergo sintering at 1300℃.The relative density of these composites after sintering have obviously improved because the smaller particle size, and furthermore there are catalyst reaction by Au wire that better the densification and mechanical properties of composites. The flexural strength was determined by using the 4-point bending technique. The strength of HA/Au wire composites does not increase when a small amount of Au wire is added. It illustrated that the Au wire would not influence flexural strength. Thus it could be known, the strength variation of HA/Au wire composites corresponds closely to their density variation. The fracture toughness was determined by using the single-edge-notched beam method. The different results were obtained as that for strength. The toughness of HA/Au wire composites has superior increased by doping trace Au wire. The toughness data shows that the increase of toughness is related to density and the doped of Au ductility material.
Huang, Ruei-shang, and 黃瑞祥. "Mechanical Properties of Ion-Exchange Hydroxyapatite Ceramics and Its Powder Preparation." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/35219891551961138720.
Full text義守大學
材料科學與工程學系
90
Abstract Two types of starting powders were used in this study, commercial and coprecipitated forms. As to coprecipitation powder, the correlation between its morphology and pH was observed in this study. Anion F- has a smaller ionic size than OH-. When these two ions were subjected to mutual ion-exchanges in the oral environments. The mechanical properties of natural teeth were expected to be affected. For further understanding the effect of mutual ion-exchanges for these two ions, sintered HA (hydroxyapatite) ceramics were used in vitro to study their mechanical properties. For ion-exchange practices, polished or further annealed specimens were ion-exchanged in the 2wt﹪NaF aqueous solution at 105℃ or further double ion-exchanged a water solution at 100℃ for different periods of time. A four-point bending method was used to measure the flexural strength of these tested specimens. The relationships between sintering temperature and mechanical properties were summarized as follows. 1. As to the effect of sintering temperature, flexural strength of these sintered specimens increased with the increasing sintering temperature. But a reverse phenomenon was found in the mechanical reliability. For example, flexural strength is 45MPa for samples sintered at T=1350℃ and 31MPa at T=1180℃. 2. HA specimens sintered at 1300℃, had a lower porosity, and its flexural strength was found not significantly affected by the various surface treatments. However, mechanical reliability of these specimens was affected by the surface roughness. 3. Even though HA ceramics sintered at 1200℃ had a higher porosity, its flexural strength was still not significantly increasing after a single, or double ion-exchange. However, mechanical reliability was about 30﹪ increasing for samples with a double ion-exchange. This was because the maximum compressive stress was located at sub-surface. The correlations among powder morphology and pH value (after 7 days) were summarized as follows. The major phase was HA when its precursor solution’s pH=3,7,&10, and b-TCP for pH=4 and 5. Therefore, with an increasing pH value, powders with HA crystal form (plate) were predominated over b-TCP (needle like).
Yang, Ming. "A characterisation of the thermal curing- and mechanical properties of polymethylmethacrylate / hydroxyapatite composites." Thesis, 2013. http://hdl.handle.net/10321/924.
Full textAim The aim of this study was to investigate the changes in exothermic polymerisation characteristics and a range of mechanical properties in PMMA/HA composites (of varying HA concentrations) against a control sample of pure PMMA. Methods Specimens of pure PMMA, and 5, 10, 15, 20 and 25 percent HA composites were made according to the specification of appropriate testing standards using the flask and packing method. Exothermic polymerisation testing was conducted on respective samples using an internal j-type thermocouple temperature sensor. The rate of temperature change and maximum temperature in relation to time were recorded. Mechanical tests included tests of flexural strength and modulus, compressive strength and modulus, tensile strength and modulus and shear strength. All specimens were kept in a controlled environment prior to testing, which was performed on a LIoyd® LR30K universal testing machine, and recorded in computer-generated logs. Results Exothermic polymerisation testing revealed a decrease in mean maximum temperature values with increasing HA content. The mean exothermic temperatures of all six groups were above 100 ̊C, with small relative temperature reductions as the HA percentage increased. The results of mechanical testing revealed that there was a significant reduction in flexural strength in the range between pure PMMA and 15 percent HA and no statistical difference in flexural modulus. There was a notable trend toward a decrease in compressive strength as HA percentage increased, achieving statistical significance at 20 and 25 percent HA, with no statistical difference in compressive modulus between samples. The tensile strength test results no significant difference between pure PMMA and composites containing up to 15 percent HA. A significant difference was noted between the 20 percent- and 25 percent HA composites and those of lower HA concentration with an increased failure risk as HA concentration was increased above 10 percent. There was a tensile modulus peak at 15 percent HA, and a significant difference between 15 percent HA composites and pure PMMA and the 10 percent HA composite. Shear strength was noted to decrease with HA percentage, with significant reduced strength between the 15 percent HA composite and pure PMMA, as well as between the 20 and 25 percent HA composites and composites of less than 10 percent HA. Conclusions The study revealed that the addition of HA to pure PMMA negatively affects the mechanical strength measured in compression, bending or shear. Tensile, compression and flexural moduli showed a gentle increase with the addition of increasing amounts of HA. The peak values were noted at 15 percent for tensile modulus and 25 percent for compressive and flexural moduli. It was recommended that the best compromise across all properties (mechanical and thermal) should be based upon the context of composite use. It was further recommended that PMMA/HA composite materials with 10 – 15 percent HA be investigated further, with due cognisance of the limitations of the present study. The researcher recommended replication of the study using a larger sample size, more refined methodology and the incorporation of additional tests, including shear modulus testing, impact resistance, bioactivity and composite degradation.
LU, CHIH-TE, and 呂致德. "Effect of low hydroxyapatite content and heat treatment on mechanical properties and in vitro degradation of biodegradable MgZnY alloy." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/54237578009160366724.
Full text國立臺灣科技大學
機械工程系
104
Abstract In this study, a Mg-based metal matrix composite was produced by casting a mixture of Mg97Zn1Y2 and 0.2 wt% of hydroxyapatite, followed by homogenization at 500℃ for 10 hours. The microstructure, mechanical properties and in vitro degradation of the material were investigated. The results show that MgZnY alloy consisting of α-Mg and Mg12YZn phase. After adding the hydroxyapatite, Vickers microhardness is slightly increased but the tensile mechanical properties are decreased; however, better corrosion resistance properties are observed after the addition of the hydroxyapatite. The corrosion mode changes from the original localized pitting corrosion mode to a more desirable uniform corrosion. The long-time corrosion rate decreases from 2.93 mm/year to 1.11 mm/year. The tensile mechanical properties of materials after homogenization are better than those after casting. The ultimate tensile strength increases from 170 MPa to 175 MPa and elongation increases from 9% to 15%. However, due to the expansion of the LPSO phase into theα-Mg region, the Galvanic corrosion becomes more severe. As a result, the corrosion properties show a downward trend.
Ravikumar, K. "Development of Multifunctional Biomaterials and Probing the Electric Field Stimulated Cell Functionality on Conducting Substrates : Experimental and Theoretical Studies." Thesis, 2015. http://hdl.handle.net/2005/3197.
Full textDespang, Florian. "Hydroxylapatit-Verbundwerkstoffe und -Biokeramiken mit parallel orientierten Porenkanälen für das Tissue Engineering von Knochen." Doctoral thesis, 2012. https://tud.qucosa.de/id/qucosa%3A26966.
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