Читать книгу Encyclopedia of Glass Science, Technology, History, and Culture - Группа авторов - Страница 138

With its derivatives such as ECR glass, E‐glass continues to dominate global commercial sales of glass fibers for reinforcement applications. The unique combination of mechanical properties, weight savings, and durability combined with a wide array of available form factors in the form of fiber diameter, strand size, resin compatibility as delivered by sizing chemistry, continuous or chopped forms, and cost‐effectiveness make E‐glass fibers by far the best value for designing and manufacturing high‐performance composites on a large scale. In parallel with ongoing improvements in E‐glass performance, technology developments associated with high‐performance fibers, i.e. re‐engineered or derivatives of S‐glass, R‐glass, and D‐glass will continue to be key focus areas in the future. These technologies serve to expand the growth of glass‐fiber reinforcements in transportation, aerospace, both traditional and renewable energy, and safety and security markets. These added technology options in glass fiber address light weight, high strength and high modulus [4, 6], improved durability, and improved electrical performance such as low signal loss and high‐speed communication in the PWB industry [5].

In developing new glass fibers, a fundamental understanding of glass network structures and glass properties for both performance and processing are critical. In boron‐containing glasses such as E‐ and D‐glass, speciation of boron in the network, i.e. BO₄ ↔ BO₃ + NBO (non‐bridging oxygen), is affected by both melting temperature and glass composition [8]; in turn, melt viscosity and glass dielectric property are affected. Besides the speciation of silicate network affected by modifying oxides [9], all commercial silicate glass fibers contain alkaline earth oxides and alumina; an in‐depth understanding of composition effect (particularly high field strength metal oxides, MO_x) on speciation of aluminum, i.e. MO_x + AlO_y ↔ MO_{x − 1} + AlO_{y + 1} (x = 7, 8 and y = 4, 5, 6) [9–11], can assist in glass design for achieving better glass mechanical properties and facilitating melting and fiber‐forming processes.