Dissertation
Dissertation > Medicine, health > Basic Medical > Medical science in general > Biomedical Engineering > Apparatus, equipment

Absorbable internal fixation device fabrication and research

Author LiMingYue
Tutor LiuChangSheng
School East China University of Science and Technology
Course Biomedical Engineering
Keywords Internal fixation devices Polylactic acid Nano-hydroxyapatite Mechanical Properties Finite Element Analysis
CLC R318.6
Type Master's thesis
Year 2012
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Clinically for the treatment of fractures and bone defects of internal fixation device for metal materials, metal materials, but there exist many problems, especially the need to remove the two operation, brings pain to the patient. The degradable polymer material instead of metal material represents the development direction of internal fixation devices. But the aseptic inflammation, generated after implantation of mechanical strength is not ideal, as well as internal fixation device processing difficulty has become a bottleneck problem impeding its clinical application. In view of the above problems, this paper choose the PLLA / nano hydroxyapatite (PLLA/nHAP) composite material as internal fixation materials, preparation of nano hydroxyapatite with medium reactor scale system (nHAP), and by surface grafting and surface modification in two ways, respectively prepared PLLA grafted nano hydroxyapatite (PLLA-g-nHAP) compatibilizer and silylation hydroxyapatite M-nHAP, and characterization. After modification, the dispersion of nHAP and PLLA composite interface compatibility is improved. Mechanical testing showed that the silane coupling agent, surface modification, the mechanical properties of the composites are greatly improved, the highest flexural strength can reach 128.43MPa, the maximum bending modulus can reach 3.61GPa. PLLA processing temperature is close to the decomposition temperature, the conventional processing method is very easy to cause the decrease of molecular weight, influence the use performance. Hybrid and injection of two processing methods used in this study, design and processing equipment, preparation of bone screws internal fixation. In order to solve the shape of complex products are difficult to determine the mechanical properties of the problem, this paper attempts to analyze the use of bone screws using finite element analysis method. Through the establishment of model, to predict PLLA/M-nHAP in shear stress of 150N (20w%) composite materials for the preparation of bone screw fixation in the human body is available.

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