Hoi-Yan Cheung

Study on the Mechanical Properties of Different Silkworm Silk Fibers

Mechanical properties of Bombyx mori, twisted B. mori, and Tussah silk fibers were investigated. Their ultimate tensile strength, elongation at break, and Young’s modulus were examined by performing a uniaxial tensile test on a single fiber. Scanning electron microscopy was used to observe the morphology of two different types of silk fiber, and to measure their apparent diameters from which the cross-sectional area of the silk fiber for stress-strain analysis can be determined. Based on experimental results obtained, it was found that Tussah silk fiber has a relatively high extensibility as compared to B. mori silk fiber and other natural fibers. Weibull analysis was also used to quantify tensile strength reproducibility of the silk fiber. Both single and twisted B. mori silk fibers have a better reproducibility of tensile properties than Tussah silk fiber.

Thermal Properties of Silk/Poly(Lactic Acid) Bio-Composite

Due to the fast development on bio-technologies, it is now possible for doctors to use patients’ cells to repair orthopedic defects. In order to support the three-dimensional tissue formation, implants made by biocompatible and bioresorbable polymers and composite materials, for providing temporary support of damaged body and cell structures have been developed. The major concern in developing implants for different surgical and orthopedic operations is the selection of suitable biomaterials. Potential materials that have been proven with experimental data on their validity for biomedical applications are metal, ceramics, polymers and the combinations of these materials (composites). For metallic materials and ceramics, they have contributed to lists of medical applications, particularly in orthopedic tissue replacements. However, there are three major limitations, they are (i) not biodegradable except biodegradable bio-ceramics, (ii) poor processability, and (iii) necessity of second surgical operation induces extra pain for the patients. Therefore, biocompatible and biodegradable polymers have shown a tremendous promise in providing more viable alternatives for tissue engineering applications.