Effect of palm stearin as single based binder on properties of ceramic injection molded of hydroxyapatite for scaffold applications / Siti Norazlini Abd Aziz

Palm stearin (PSr) or known as vegetable fat has been introduced in injection moulding processes which has great potential as an alternative binder in a binder system.This study presents the processing of Hydroxyapatite (Caio(P04)6(OH)2) mixed with 100 vol.% of single based binder palm stearin (PSr)...

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Main Author:	Abd Aziz, Siti Norazlini
Format:	Thesis
Language:	English
Published:	2017
Subjects:	Biomaterials
Online Access:	https://ir.uitm.edu.my/id/eprint/67517/1/67517.pdf
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spelling	my-uitm-ir.675172023-03-06T08:55:06Z Effect of palm stearin as single based binder on properties of ceramic injection molded of hydroxyapatite for scaffold applications / Siti Norazlini Abd Aziz 2017 Abd Aziz, Siti Norazlini Biomaterials Ceramic technology. Pottery Palm stearin (PSr) or known as vegetable fat has been introduced in injection moulding processes which has great potential as an alternative binder in a binder system.This study presents the processing of Hydroxyapatite (Caio(P04)6(OH)2) mixed with 100 vol.% of single based binder palm stearin (PSr) using CIM. The main objective of the research was to determine the optimum formulation of powder-binder mixture via mixing torque and rheological analysis. The process generally started with the selected commercial HAp powder and the binder in correct proportions. From the CPVP test, the critical loading was 70.64%, thus the formulation was formulated below 2-5 vol.% critical loadings. Four different volume fractions of the powder were investigated: 62, 64, 66, and 68 vol.%. During the rheological test, the feedstock containing the mixture and the binder exhibited pseudoplastic properties, which was lower than 200 Pa.s with function of shear rate.The injection moulding process was successfully carried out in the injection temperature range of 65°C to 70°C which corresponded to 300 kPa to 400 kPa injection pressure being applied and followed the ASTM CI424-10. Compared to other previous research, the temperature used was slightly higher than 130°C due to the absence of a backbone binder. The moulded dumbell shape was completely debound and sintered in one complete cycle using a single furnace with the presence of wieking media to remove the PSr binder. Next, the sample was subsequently sintered at three different temperatures of 900°C, 1000°C and 1100°C to allow diffusion of the particles. Besides that, the DSC result showed the melting point of the PSr binder was at 62°C, thus the mixing temperature was applied slightly higher at 70°C which allowed for homogenous mixing. The shrinkage result showed that higher formulation (68 vol.%) resulted in - lower shrinkage properties; higher sintering temperature contributed to higher shrinkage properties. This was due to the higher powder loading which meant smaller compact volume shrinkage and easier dimension tolerance control,which is very important for complex injection molded parts. Next, the pore size of the as-sintered sample was measured using a micrometric instrument. The porosity result obtained showed that higher volume fraction of the powder loading resulted in higher porosity; 62 vol.% resulted in about 38% porosity and 68 vol.% resulted in about 41% porosity respectively. The porous structure shown in SEM images was highly interconnected; thus it promoted better bone tissue ingrowth for implant application. The XRD result obtained showed the TCP formation was at 1100°C thus decreasing the compressive strength of HAp. 2017 Thesis https://ir.uitm.edu.my/id/eprint/67517/ https://ir.uitm.edu.my/id/eprint/67517/1/67517.pdf text en public masters Universiti Teknologi MARA (UiTM) Faculty of Mechanical Engineering Abu Bakar, Mimi Azlina
institution	Universiti Teknologi MARA
collection	UiTM Institutional Repository
language	English
advisor	Abu Bakar, Mimi Azlina
topic	Biomaterials Biomaterials
spellingShingle	Biomaterials Biomaterials Abd Aziz, Siti Norazlini Effect of palm stearin as single based binder on properties of ceramic injection molded of hydroxyapatite for scaffold applications / Siti Norazlini Abd Aziz
description	Palm stearin (PSr) or known as vegetable fat has been introduced in injection moulding processes which has great potential as an alternative binder in a binder system.This study presents the processing of Hydroxyapatite (Caio(P04)6(OH)2) mixed with 100 vol.% of single based binder palm stearin (PSr) using CIM. The main objective of the research was to determine the optimum formulation of powder-binder mixture via mixing torque and rheological analysis. The process generally started with the selected commercial HAp powder and the binder in correct proportions. From the CPVP test, the critical loading was 70.64%, thus the formulation was formulated below 2-5 vol.% critical loadings. Four different volume fractions of the powder were investigated: 62, 64, 66, and 68 vol.%. During the rheological test, the feedstock containing the mixture and the binder exhibited pseudoplastic properties, which was lower than 200 Pa.s with function of shear rate.The injection moulding process was successfully carried out in the injection temperature range of 65°C to 70°C which corresponded to 300 kPa to 400 kPa injection pressure being applied and followed the ASTM CI424-10. Compared to other previous research, the temperature used was slightly higher than 130°C due to the absence of a backbone binder. The moulded dumbell shape was completely debound and sintered in one complete cycle using a single furnace with the presence of wieking media to remove the PSr binder. Next, the sample was subsequently sintered at three different temperatures of 900°C, 1000°C and 1100°C to allow diffusion of the particles. Besides that, the DSC result showed the melting point of the PSr binder was at 62°C, thus the mixing temperature was applied slightly higher at 70°C which allowed for homogenous mixing. The shrinkage result showed that higher formulation (68 vol.%) resulted in - lower shrinkage properties; higher sintering temperature contributed to higher shrinkage properties. This was due to the higher powder loading which meant smaller compact volume shrinkage and easier dimension tolerance control,which is very important for complex injection molded parts. Next, the pore size of the as-sintered sample was measured using a micrometric instrument. The porosity result obtained showed that higher volume fraction of the powder loading resulted in higher porosity; 62 vol.% resulted in about 38% porosity and 68 vol.% resulted in about 41% porosity respectively. The porous structure shown in SEM images was highly interconnected; thus it promoted better bone tissue ingrowth for implant application. The XRD result obtained showed the TCP formation was at 1100°C thus decreasing the compressive strength of HAp.
format	Thesis
qualification_level	Master's degree
author	Abd Aziz, Siti Norazlini
author_facet	Abd Aziz, Siti Norazlini
author_sort	Abd Aziz, Siti Norazlini
title	Effect of palm stearin as single based binder on properties of ceramic injection molded of hydroxyapatite for scaffold applications / Siti Norazlini Abd Aziz
title_short	Effect of palm stearin as single based binder on properties of ceramic injection molded of hydroxyapatite for scaffold applications / Siti Norazlini Abd Aziz
title_full	Effect of palm stearin as single based binder on properties of ceramic injection molded of hydroxyapatite for scaffold applications / Siti Norazlini Abd Aziz
title_fullStr	Effect of palm stearin as single based binder on properties of ceramic injection molded of hydroxyapatite for scaffold applications / Siti Norazlini Abd Aziz
title_full_unstemmed	Effect of palm stearin as single based binder on properties of ceramic injection molded of hydroxyapatite for scaffold applications / Siti Norazlini Abd Aziz
title_sort	effect of palm stearin as single based binder on properties of ceramic injection molded of hydroxyapatite for scaffold applications / siti norazlini abd aziz
granting_institution	Universiti Teknologi MARA (UiTM)
granting_department	Faculty of Mechanical Engineering
publishDate	2017
url	https://ir.uitm.edu.my/id/eprint/67517/1/67517.pdf
_version_	1783735694556921856

Effect of palm stearin as single based binder on properties of ceramic injection molded of hydroxyapatite for scaffold applications / Siti Norazlini Abd Aziz

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