High Performance Fibers

Glass

• When people speak of glass, they ordinarily mean a transparent, shiny substance that breaks rather easily. They may think of the glass in windows and the glass used in eyeglasses as being the same material. Actually, they are not. There are many kinds of glass.

Types of glass• A glass• Soda lime silicate glasses used where the strength, durability, and good

electrical resistivity of E Glass are not required.• C glass• Calcium borosilicate glasses used for their chemical stability in corrosive acid

environments• E glass• Alumina-calcium-borosilicate glasses with a maximum alkali content of 2 wt.%

used as general purpose fibers where strength and high electrical resistivity are required.

S glass• Magnesium aluminosilicate glasses used for textile substrates or reinforcement

in composite structural applications which require high strength, modulus, and stability under extreme temperature and corrosive environments

Types of glass

High Performance Fibers

E Glass

Back Ground

• E-Glass or electrical grade glass was originally developed for stand off insulators for electrical wiring. It was later found to have excellent fibre forming capabilities and is now used almost exclusively as the reinforcing phase in the material commonly known as fiberglass.

Fibre Manufacturing

• Glass fibres are generally produced using melt spinning techniques. These involve melting the glass composition into a platinum crown which has small holes for the molten glass to flow.

• Continuous fibres can be drawn out through the holes and wound onto spindles, while short fibres may be produced by spinning the crown, which forces molten glass out through the holes centrifugally. Fibres are cut to length using mechanical means or air jets.

Fibre Manufacturing

• Fibre dimension and to some extent properties can be controlled by the process variables such as melt temperature (hence viscosity) and drawing/spinning rate.

• The temperature window that can be used to produce a melt of suitable viscosity is quite large, making this composition suitable for fibre forming.

Fibre Manufacturing

• As fibres are being produced, they are normally treated with sizing and coupling agents. These reduce the effects of fibre-fibre abrasion.

• Other treatments may also be used to promote wetting and adherence of the matrix material to the fibre.

Batch mixing and melting

• The glass melting process begins with the weighing and blending of selected raw materials.

• In modern fiberglass plants, this process is highly automated, with computerized weighing units and enclosed material transport systems.

• The individual components are weighed and delivered to a blending station where the batch ingredients are thoroughly mixed before being transported to the furnace.

Batch mixing and melting

• Batch is delivered into the furnace section for melting at about 1400°C, removal of gaseous inclusions, and homogenization.

• Then, the molten glass flows into the refiner section, where the temperature of the glass is lowered to about 1260°C.

• The molten glass next goes to the forehearth section located directly above the fiber-forming stations.

Fiberizing and Sizing

• The conversion of molten glass in the forehearth into continuous glass fibers is basically an attenuation process

• Bushing: the molten glass flows to numerous heat resistance platinium trays which have thousands of small precisely tubular openings called bushings

• The fibers are drawn down and cooled rapidly as they exit the bushing.

sizing

• A sizing is then applied to the surface of the fibers by passing them over an applicator that continually rotates through the sizing bath to maintain a thin film through which the glass filaments pass.

• The components of the sizing impart strand integrity, lubricity, resin compatibility, and adhesion properties to the final product, thus tailoring the fiber properties to the specific end-use requirements

Composition

• E-Glass is a low alkali glass with a typical nominal composition

• SiO2 54wt%

• Al2O3 14wt%• CaO+MgO 22wt% • B2O3 10wt%

• Na2O+K2O less then 2wt%. • Some other materials may also be present at

impurity levels.

Properties

• Low cost.• High production rate.• Non flammable.• Resistant to heat.• Good chemical resistance.• Able to maintain strength properties over a

wide range of conditions.• Good electrical insulation

Properties

ApplicationsComposite Materials

• The use of E-Glass as the reinforcement material in polymer matrix composites is extremely common.

• Optimal strength properties are gained when straight, continuous fibres are aligned parallel in a single direction.

• To promote strength in other directions, laminate structures can be constructed, with continuous fibres aligned in other directions.

• Such structures are used in storage tanks. • Random direction matts and woven fabrics are also

commonly used for the production of composite panels.

High Performance Fibers

S Glass

S Glass

• S-glass materials are high strength glass fibers made from magnesium alumina silicate system which meets the needs of military and other applications where high strength and high performance is required.

Compared to E-Glass, S-glass has the following features and benefits

• 30 to 40% better tensile strength.• 16 to 20% higher modulus of elasticity.• 100 to 150 degrees Celsius better temperature

endurance. • higher fatigue resistance.• Excellent impact resistance because of the

high elongation to breakage.• High ageing and corrosion resistance.• Weight saving at the same performance

Applications

• Aerospace, • Marine • Arms industries due to its high tensile strength

and higher modulus of elasticity when compared to e-glass.