Fiber to waterproof, why be afraid of water? ,

the tensile strength of the fiber, mainly depends on the fiber surface damage. If applying for optical fiber of the stretching tension, a certain intensity, the stress will focus on lesions, lead to crack expanding until the fracture. The surface of fiber damage over time will gradually expand the fiber fracture. The main factors include: stress in the fiber damage expand, water, temperature and so on. Aquarium glass, glass and fiber glass are afraid of water, the difference is the glass, the glass is very thick, the thickness is 3 mm, 5 mm, lOmm, even with O. 05 mm crack lines also does not affect the strength of the glass, and also to the naked eye can not see. And the fiber glass is different, fiber glass diameter only O. 125 mm, as thick as a human hair, if you have O. 05 mm crack, optical fiber diameter was left with O. 075 mm, so fiber is extremely easy to broken fiber. This is why the aquarium glass, glass is not afraid of water, fear of water and fiber glass. The need of an optical fiber waterproof. Fiber optic cable after need to protect optical fiber has two requirements: less fiber mechanical and optical fiber to be waterproof. Plastic protection layer, the outermost layers of the cable metal sheath is inside, then there is the water expansion of water-resistant, ointment and optical fiber cable core stick together. Optical fiber has four waterproof barrier, namely: plastic sheath, metallic sheath, water-resistant, ointment. Optical fiber why so afraid of water, the home of the glass, glass, why not afraid of water instead of waterproof, is why the glass is so different? And from the Angle of physical fiber reason is afraid of water: fiber glass ( Si04) Silicon oxygen tetrahedron mutual connection, as shown in figure 1. In a Si - O— Si a network, the oxygen in the form of oxygen atoms in bridge. But in water environment, the glass surface moisture adsorption, hydrolysis reaction slowly, then lead to the original network a Si a 0 a Si si-o bond rupture, in a bridge into the bridge oxygen as shown in figure 2, the result of glass cracks, and the crack growth. In actual use conditions, therefore, should pay attention to do a good job, the waterproof of the fiber not dip fiber in water.