| Summary: | 碩士 === 龍華科技大學 === 工程技術研究所 === 97 === In earlier day’s implantating metal screws in bone injury tissues is required. To remove the implanted metal we have to perform an operation again after surgery. Patients in accordance with the restoration of long time will result in harm due to the metal implants. Patients with osteoporotic bone can’t use metal materials for implantation with bone tissue for the use of reinforcement. To address the out comings of biomedical ceramic and biodegradable plastic materials instead of metal implants, production of complex bone screws which enhances the reinforcement of the function of the bone tissue and need not to be removed from a patient. It is not only for economic benefits but also to eliminate the second surgery in patients with injury.
In this study, biomedical ceramic and biodegradable plastic complex bone screw is used for implants instead of metal, presently homogeneous mixing is done with complex to gain mechanical property relation. The role of injection molding technique for biomedical complex to make the bone screw, which reinforces the bone operation.
Biomedical ceramic and biodegradable plastic complex materials were prepared from the base of hydroxyapatite (HAP) and polylactic acid (PLA) to produce an alternative composite bone screw instead of metal screw. In accordance with M.Wang literature in the study we focussed to increase the proportion of reinforcement of composite material. The composition of hydroxyapatite were 10wt%, 20wt%, 40wt%, required amount of PLA substrate was mixed with the HAP compositions and insertion of the mixed solution into the mold results in manufacturing the composites by optimizing the parameters for various test. In accordance with ASTM standard, test piece has been successfully prepared by using injection molding with tensile and impact test. At the same time using injection molding technology with hydroxyapatite and polylactic acid, composites of bone screw implantation has been successfully prepared.
Composites of micro-structure and the feedstock of the Scanning Electron Microscopy (SEM) with the universal testing machine provide good results in the assessment. We have investigated the mechanical properties through material degradation experiment and found that tensile strength for 20wt% of HAP is the best performance of complex materials whose tensile strength was about 70.09MPa. The data from Young's modulus for 20wt% of HAP provides to be the best performance of complex materials, whose Young's modulus was about 539MPa. 20wt% of HAP have an impact strength with good performance of complex materials, and the impact strength was found to be 2.79kgf.cm/cm. 10wt% of HAP ‘s flexural strength restoration material is found to be best and the bending strength was130MPa.
Degradation of complex material for the test results provides no significant weight loss and the experiment caused by absorption of water, compared with the Young’s modulus of the complex material to 20wt% of HAP’ s Young’s modulus was reported as the best complex material. Bending strength of bone screws to 10wt% HAP gives the best flexural strength composites .
In summary,40wt% with complex material of high hardness and wear properties plays an important in the mechanical properties of the other declined, but our goal is to fill the bone defect within the required holes to high levels of complex material more suitable for the production of bone screws.
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