This study is focused on the role of nano hydroxyapatite particles on the mechanical properties o... more This study is focused on the role of nano hydroxyapatite particles on the mechanical properties of PMMA/ HA nanocomposites. In order to achieve a proper and homogeneous distribution of HA particles in the polymer matrix, mixer milling process was applied. Wear, compression and three-point bending tests were conducted. It was observed that wear rate decreased by increasing in HA content in both atmosphere and artificial saliva. The results of compression tests showed that the addition of 2.5 percent HA to PMMA promoted ultimate compressive strength, yield strength and modulus while caused to decrease elongation at break. Also it was elucidated that addition of HA more than 2.5 wt% caused a decrease in both ultimate compressive strength and compression yield strength and an increase in elongation at break. The results of three-point bending tests on the PMMA cements containing 2.5 percent HA demonstrated the maximum bending strength value and modulus among all the HA containing formulations. However there was no direct proportionality between the results of bending tests and the HA content and the addition of HA to PMMA (up to 10 wt%) did not change the bending properties significantly.
Journal of the Mechanical Behavior of Biomedical Materials, 2016
Metacarpophalangeal joint implants have been usually made of silicone rubber. In the current stud... more Metacarpophalangeal joint implants have been usually made of silicone rubber. In the current study, silica nano particles and polypropylene fibers were added to silicone rubber to improve silicone properties. The effect of the addition of silica nano particles and polypropylene fibers on the tensile behavior of the resultant composites were investigated. Composite samples with different content of PP fibers and Silica nano particles (i. e. 0, 1 and 2wt%) as well as the hybrid composite of silicone rubber with 1wt% SiO2 and 1wt% PP fiber were prepared. Tensile tests were done at constant cross head speed. To study the body fluid effect on the mechanical properties of silicone rubber composites, samples soaked in simulated body fluid (SBF) at 37°C were also tested. The morphology of the samples were studied by scanning electron microscope. Results of analysis revealed that an increase in PP fibers and silica nano particles content to 2wt%, increases the tensile strength of silicone rubber of about 75% and 42% respectively. It was found out that the strength of the samples decreases after being soaked in simulated body fluid, though composites with PP fibers as the reinforcement showed less property degradation.
Iranian Journal of Science and Technology: Transactions of Mechanical Engineering
Aluminum foams are a novel branch of advanced materials with superior properties. Sandwich struct... more Aluminum foams are a novel branch of advanced materials with superior properties. Sandwich structures with aluminum foam core are good energy absorbers. In this paper, mechanical properties and energy absorption of aluminum foam sandwich panels subjected to quasi-static perforation tests with conical-nosed indenter were investigated experimentally. For this purpose sandwich panels consisted of two aluminum face-sheets and a closed cell aluminum foam core were fabricated. Quasi-static perforation tests on fully fixed sandwich panels were carried out by a universal testing machine at a cross head speed of 0.02 mm/s. Force-displacement curves were recorded and peak piercing force and absorbed energy of sandwich panels was calculated accordingly. Effects of foam core density (0.5, 0.6 and 0.7 g/cm3) and thickness of face-sheets (0.6, 1 and 2 mm) and foam core (10, 20 and 30 mm) on the mechanical properties and energy absorption of samples were discussed. The results showed that increasi...
نانولوله هاي كربني با داشتن دانسيته كم، نسبت سطح به حجم بالا و ويژگي هاي الكتريكي، مكانيكي و حرار... more نانولوله هاي كربني با داشتن دانسيته كم، نسبت سطح به حجم بالا و ويژگي هاي الكتريكي، مكانيكي و حرارتي منحصربفرد مورد توجه بسياري از محققين قرار گرفتهاند. با اين وجود نانولولههاي كربني منفرد يكديگر را با نيروي 0/5eVجذب ميكنند. اين ويژگي سبب كاهش پراكندگي اين مواد در حلالهاي آبي و زمينههاي پليمري ميشود. در اين تحقيق، به منظور جلوگيري از تجمع نانولوله كربني در سيال و ايجاد سطحي آبدوست براي آنها، فرايند اسيد شويي نانولوله هاي كربني با اسيد نيتريكغليظ ( 65 %) و با استفاده از حمام آلتراسون و همزن مغناطيسي انجام شد. سپس پايداري نانولولههاي كربني خام و اسيد شوييشده در آب مورد بررسي قرار گرقت. آناليز ساختاري و ميكروسكوپي نانولوله كربني خام و اسيد شويي شده با استفاده از پراش اشعه ايكسXRD)و ميكروسكوپ الكتروني عبوريTEM) مورد ارزيابي قرار گرفت. بررسي كيفي گروههاي عاملي بر سطح نانولولههاي كربني خام و اسيد شويي با استفاده از طيف سنجي مادون قرمز فوريهFTIR) انجام گرفت . همچنين براي بررسي پايداري نانولوله كربني خام و اسيد شويي شده در آب مقطر از پتانسيل زتا استفاده شد
Encyclopedia of Biomedical Polymers and Polymeric Biomaterials, 2016
ABSTRACT Motivated by diverse requirements of biomedical applications, a lot of research on devel... more ABSTRACT Motivated by diverse requirements of biomedical applications, a lot of research on developing shape memory polymer composites and blends has been conducted. By preparing these materials, the properties of shape memory polymers (SMPs) could be tailored to the requirements of biomedical applications. Besides, SMP composites and blends can exhibit novel properties and substantially broaden the applicability of SMPs in the biomedical field. The research on SMP composites and blends has been focused on the improvement of properties of SMPs, addition of new functions besides shape memory effect, realization of athermal stimulus methods, and creation of novel SMPs. In this article, a detailed review of these studies is provided.
Solution combustion synthesis (SCS) is a well-known method for production of different metal oxid... more Solution combustion synthesis (SCS) is a well-known method for production of different metal oxides and composite materials such as metal matrix composites. To the best of our knowledge, producing of metal matrix composite needs an extra reduction step after combustion synthesis. In the current research, the authors introduced a novel method to eliminate the reduction step and showed that Cu matrix composite could be produced just in one-step. For this purpose, Cu(NO3)2·3H2O and Al (NO3)3·9H2O were used as oxidizers and urea as fuel, and one-step combustion synthesis was performed in the presence of graphite. The structure and morphology of the products were studied by XRD, SEM and TEM techniques, respectively. XRD patterns proved that the presence of graphite could prevent formation of copper oxides. SEM and TEM micrographs showed that Cu matrix reinforced with nano-sized alumina could be achieved in one-step through SCS method.► The heat released from reaction can produce Cu–Al2O3 nanocomposite with high purity. ► In the presence of graphite, the combustion temperature has decreased. ► Graphite adding helps to produce the nanocomposite just in one-step.
ABSTRACT In this research, we successfully synthesized Zinc oxide nano-particles via hydrothermal... more ABSTRACT In this research, we successfully synthesized Zinc oxide nano-particles via hydrothermal method at low temperature using Zn(CH3COO)2.2H2O and KOH as starting materials in alcoholic media. The solution was prepared in a particular process at 65 °C. After several washing and centrifuging, the final product was characterized with x-ray diffraction (XRD) and transition electron microscopy (TEM). XRD result confirmed ZnO with Hexagonal wurtzite structure with a crystallite size of 23.08 nm. The TEM images proved ZnO nano-sized particles with mean particle size of 25.47 nm.
This study is focused on the role of nano hydroxyapatite particles on the mechanical properties o... more This study is focused on the role of nano hydroxyapatite particles on the mechanical properties of PMMA/ HA nanocomposites. In order to achieve a proper and homogeneous distribution of HA particles in the polymer matrix, mixer milling process was applied. Wear, compression and three-point bending tests were conducted. It was observed that wear rate decreased by increasing in HA content in both atmosphere and artificial saliva. The results of compression tests showed that the addition of 2.5 percent HA to PMMA promoted ultimate compressive strength, yield strength and modulus while caused to decrease elongation at break. Also it was elucidated that addition of HA more than 2.5 wt% caused a decrease in both ultimate compressive strength and compression yield strength and an increase in elongation at break. The results of three-point bending tests on the PMMA cements containing 2.5 percent HA demonstrated the maximum bending strength value and modulus among all the HA containing formulations. However there was no direct proportionality between the results of bending tests and the HA content and the addition of HA to PMMA (up to 10 wt%) did not change the bending properties significantly.
Journal of the Mechanical Behavior of Biomedical Materials, 2016
Metacarpophalangeal joint implants have been usually made of silicone rubber. In the current stud... more Metacarpophalangeal joint implants have been usually made of silicone rubber. In the current study, silica nano particles and polypropylene fibers were added to silicone rubber to improve silicone properties. The effect of the addition of silica nano particles and polypropylene fibers on the tensile behavior of the resultant composites were investigated. Composite samples with different content of PP fibers and Silica nano particles (i. e. 0, 1 and 2wt%) as well as the hybrid composite of silicone rubber with 1wt% SiO2 and 1wt% PP fiber were prepared. Tensile tests were done at constant cross head speed. To study the body fluid effect on the mechanical properties of silicone rubber composites, samples soaked in simulated body fluid (SBF) at 37°C were also tested. The morphology of the samples were studied by scanning electron microscope. Results of analysis revealed that an increase in PP fibers and silica nano particles content to 2wt%, increases the tensile strength of silicone rubber of about 75% and 42% respectively. It was found out that the strength of the samples decreases after being soaked in simulated body fluid, though composites with PP fibers as the reinforcement showed less property degradation.
Iranian Journal of Science and Technology: Transactions of Mechanical Engineering
Aluminum foams are a novel branch of advanced materials with superior properties. Sandwich struct... more Aluminum foams are a novel branch of advanced materials with superior properties. Sandwich structures with aluminum foam core are good energy absorbers. In this paper, mechanical properties and energy absorption of aluminum foam sandwich panels subjected to quasi-static perforation tests with conical-nosed indenter were investigated experimentally. For this purpose sandwich panels consisted of two aluminum face-sheets and a closed cell aluminum foam core were fabricated. Quasi-static perforation tests on fully fixed sandwich panels were carried out by a universal testing machine at a cross head speed of 0.02 mm/s. Force-displacement curves were recorded and peak piercing force and absorbed energy of sandwich panels was calculated accordingly. Effects of foam core density (0.5, 0.6 and 0.7 g/cm3) and thickness of face-sheets (0.6, 1 and 2 mm) and foam core (10, 20 and 30 mm) on the mechanical properties and energy absorption of samples were discussed. The results showed that increasi...
نانولوله هاي كربني با داشتن دانسيته كم، نسبت سطح به حجم بالا و ويژگي هاي الكتريكي، مكانيكي و حرار... more نانولوله هاي كربني با داشتن دانسيته كم، نسبت سطح به حجم بالا و ويژگي هاي الكتريكي، مكانيكي و حرارتي منحصربفرد مورد توجه بسياري از محققين قرار گرفتهاند. با اين وجود نانولولههاي كربني منفرد يكديگر را با نيروي 0/5eVجذب ميكنند. اين ويژگي سبب كاهش پراكندگي اين مواد در حلالهاي آبي و زمينههاي پليمري ميشود. در اين تحقيق، به منظور جلوگيري از تجمع نانولوله كربني در سيال و ايجاد سطحي آبدوست براي آنها، فرايند اسيد شويي نانولوله هاي كربني با اسيد نيتريكغليظ ( 65 %) و با استفاده از حمام آلتراسون و همزن مغناطيسي انجام شد. سپس پايداري نانولولههاي كربني خام و اسيد شوييشده در آب مورد بررسي قرار گرقت. آناليز ساختاري و ميكروسكوپي نانولوله كربني خام و اسيد شويي شده با استفاده از پراش اشعه ايكسXRD)و ميكروسكوپ الكتروني عبوريTEM) مورد ارزيابي قرار گرفت. بررسي كيفي گروههاي عاملي بر سطح نانولولههاي كربني خام و اسيد شويي با استفاده از طيف سنجي مادون قرمز فوريهFTIR) انجام گرفت . همچنين براي بررسي پايداري نانولوله كربني خام و اسيد شويي شده در آب مقطر از پتانسيل زتا استفاده شد
Encyclopedia of Biomedical Polymers and Polymeric Biomaterials, 2016
ABSTRACT Motivated by diverse requirements of biomedical applications, a lot of research on devel... more ABSTRACT Motivated by diverse requirements of biomedical applications, a lot of research on developing shape memory polymer composites and blends has been conducted. By preparing these materials, the properties of shape memory polymers (SMPs) could be tailored to the requirements of biomedical applications. Besides, SMP composites and blends can exhibit novel properties and substantially broaden the applicability of SMPs in the biomedical field. The research on SMP composites and blends has been focused on the improvement of properties of SMPs, addition of new functions besides shape memory effect, realization of athermal stimulus methods, and creation of novel SMPs. In this article, a detailed review of these studies is provided.
Solution combustion synthesis (SCS) is a well-known method for production of different metal oxid... more Solution combustion synthesis (SCS) is a well-known method for production of different metal oxides and composite materials such as metal matrix composites. To the best of our knowledge, producing of metal matrix composite needs an extra reduction step after combustion synthesis. In the current research, the authors introduced a novel method to eliminate the reduction step and showed that Cu matrix composite could be produced just in one-step. For this purpose, Cu(NO3)2·3H2O and Al (NO3)3·9H2O were used as oxidizers and urea as fuel, and one-step combustion synthesis was performed in the presence of graphite. The structure and morphology of the products were studied by XRD, SEM and TEM techniques, respectively. XRD patterns proved that the presence of graphite could prevent formation of copper oxides. SEM and TEM micrographs showed that Cu matrix reinforced with nano-sized alumina could be achieved in one-step through SCS method.► The heat released from reaction can produce Cu–Al2O3 nanocomposite with high purity. ► In the presence of graphite, the combustion temperature has decreased. ► Graphite adding helps to produce the nanocomposite just in one-step.
ABSTRACT In this research, we successfully synthesized Zinc oxide nano-particles via hydrothermal... more ABSTRACT In this research, we successfully synthesized Zinc oxide nano-particles via hydrothermal method at low temperature using Zn(CH3COO)2.2H2O and KOH as starting materials in alcoholic media. The solution was prepared in a particular process at 65 °C. After several washing and centrifuging, the final product was characterized with x-ray diffraction (XRD) and transition electron microscopy (TEM). XRD result confirmed ZnO with Hexagonal wurtzite structure with a crystallite size of 23.08 nm. The TEM images proved ZnO nano-sized particles with mean particle size of 25.47 nm.
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