|Budget Amount *help
¥1,700,000 (Direct Cost : ¥1,700,000)
Fiscal Year 1995 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1994 : ¥1,000,000 (Direct Cost : ¥1,000,000)
X-ray Diffraction method was utilized to investigate the mechanism of stress transfer, stress concentration, and resulting reinforcement effect in polymer composite. Fracture mechanism based on the debonding at the interface between fiber and matrix, the effect of adhesion on the reinforcement have been also investigated. First, the stress was applied to the high-performance polyethylene fiber uni- directionally reinforced epoxy composite in the direction perpendicular to the fiber direction. The applied stress was found to be transmitted to the incorporated fiber, which could be easily detected as the diffraction peak shift of the equatorial x-ray diffraction peak. The stress transmitted to the fiber can be estimated by multiplying the crystal strain by the elastic modulus of the crystalline regions of polyethylene. By using this "X-ray Diffraction Technique" , the stress on tghe incorporated fiber, that is, the reinforced effect in polymer composite can be determined in situ and non-destructively. When the fiber was treated with chromic acid, the applied stress became well trasmitted to the fiber, which indicated that the adhesion between the fiber and matrix plays an important role for the reinforcement in the perpendicular direction. Further, the fracture mode was found to be changed by the surface treatment of the fiber. The mechanical property was found to be expressed by using the role of mixture in the direction of fiber axis, which was also clarified by utilizing the x-ray diffraction. Same kinds of experiments were also performed for carbon fiber reinforced composite, and poly (p-phenylene benzobisoxazole) reinforced composites. This technique will be also applied to investigate the effect of moisture, time, temperature.