PAN-based carbon fibers during the formation of sh

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PAN-based carbon fibers during the formation of sheath-core structure evolution

Pui Yin Brown does not blink blink sector is very difficult to face significant thickening was clearly worried I was obviously the amount of carbonation process was 5.2 sheath core structure Figure 3 shows the evolution of the carbonization process, the fiber optical transverse polishing s tincture analysis of photographs can be seen from the figure, with the temperature increase Zhen,[link widoczny dla zalogowanych], fiber diameter decreases, the optical fiber cross-section reflection intensity of child gradually. Sheath and the core of the early light and dark contrast in the carbonization temperature increased with the carbonation, about 500 ~ C,[link widoczny dla zalogowanych], the core is very easy to embed polishing powder particles, resulting in core is very dark, indicating that the fibrous sheath and the core and then the hardness the difference of the J:. When the carbonization temperature exceeds 500 \. ● 300 ℃ 500 ℃ 700 ℃ 1250 ℃ the process of Figure 3 carbon fiber optical microscope pictures in Figure 4 shows the polarized light, the fiber core vertical A shake is the extinction image with carbonization temperature. To be seen from the figure ijt: j Yi Mountain stupid Zhu beam 19 § 1 ■ grapefruit 2700 ℃ 1250 ℃ carbonization process in Figure 4 POM images of fiber cross-section perpendicular to fiber rotation 45. Out the initial 300 ~ C in the carbonization, the fiber cross-sectional point of no secondary core structure of the rain. This may be because pre-oxidation into carbon fibers, because of its sheath and core have a high orientation structure along the fiber axis, and at very low temperature carbonization impatient some of them still maintain orientation, so in the cross-polarized light It does not come out under the observation of sheath-core structure. But when the carbonization temperature rose to 400 = C, the fiber was immediately shown the \Sheath-core \, the molecular chain orientation along the fiber axis through the reactor cross-linking and cleavage to maintain or enhance the core since I came to fully stabilized material, carbonization,[link widoczny dla zalogowanych], the molecular chain due to thermal movement and cracking occurred unremitting solution oriented strand breaks. resulting in appears under the cross-polarized light due to the formation of different crystalline orientation of sheath-core structure. Once the structure of the management, it remains to carbon terminated. raid 2 shows the polarized light in color (in the front with a polarizer gypsum board) analysis of state, the polished surface of the sheath and the longitudinal fibers Sit color changes. It can be seen from the table,[link widoczny dla zalogowanych], with the Wo temperature increase, \, and the changes mainly occurred in the 700 ℃ like before, 700 ~ C after the possession of color Jifeng consistent. And: woolen rug cents: In the 400 ~ C when the color began to curl, 500 ~ C in former times to the child after the flounder pocket 10 ¨ l ■ t one point off ● 2 phosphating temperature. Aunt Blue light blue sheath 300 {0. , 400I greenish blue analogy i. 0500I yellowish green Pi 1.3700I Green Orange Red 1.1600 1.5900l1. , I25Ol25 was basically the same purple. In addition, as the carbonization temperature, the fiber polishing surface relative intensity of the reflected light upward trend, 500 = C before the upward trend in small, 500 ℃ higher after the rise. As the intensity of reflected light and carbon levels on a large scale stacking,[link widoczny dla zalogowanych], \structure began in the early pre-oxidation, Vladimir will evolve to the carbon fiber fabric. so you can infer fiber pre-oxidation of carbon fiber to control the final structure of the important steps Qiang. (2) early in the carbon fiber of the sheath and garlic on incident. the reflection of light with different intensity of the core is darker than the sheath, indicating that the hardness of the sheath and core have a greater difference. but with the carbon-million books in, this contrast decreases, 700 = C and then gradually eliminate 'lose. from the crystallization of the fiber orientation of view, the orientation of the sheath when the degree of carbonation is maintained or strengthened, while the core is at 400 ~ C when the solution began to approach, different orientation to form the \And has been retained to the carbon fibers. (3) color polarization analysis showed that the carbonization process, \