Views: 4 Author: Site Editor Publish Time: 2022-12-02 Origin: Site
Fiberglass is a common fiber-reinforced plastic that uses glass fibers.The fibers can be randomly arranged,flattened into a sheet called chopped strand mat, or woven into glass cloth.The plastic matrix can be a thermoset polymer matrix-most commonly based on thermoset polymers such as epoxy,polyester or vinyl ester resins or a thermoplastic.It is cheaper and more flexible than carbon fiber,stronger than many metals,non-magnetic,non-conductive,transparent to electromagnetic radiation,can be molded into complex shapes,and in many cases is chemically inert.Applications include aircraft,boats,automobiles,bathtubs and enclosures,swimming pools,hot tubs,septic tanks,tanks,roofs,pipes,cladding,orthopedic castings,surfboards and enclosures.Other common names for glass fibers are Glass Fiber Reinforced Plastic (GRP),Glass Fiber Reinforced Plastic (GFRP).Since glass fibers themselves are sometimes referred to as "fiberglass,"composites are also known as fiberglass-reinforced plastics (FRP).In this document, by convention,"glass fiber" refers to the complete fiber-reinforced composite, not just the glass fibers within it.Carbon Fiber Reinforced Polymer is a similar composite material where the reinforcement is carbon fiber.
Unlike glass fibers used for insulation, in order for the final structure to be strong,the surface of the fibers must be almost completely free of defects,as this allows the fibers to achieve gigapascal tensile strengths.If a bulk glass were defect-free,it would be as strong as fiberglass;however,it is often impractical to produce and maintain bulk material in a defect-free state outside of laboratory conditions.
The process of making fiberglass is called pultrusion.The glass fiber manufacturing process suitable for reinforcement materials is to gradually melt minerals such as quartz sand, limestone,kaolin,fluorite,colemanite,and dolomite in a large furnace until a liquid is formed.Then extruded through a sleeve (spinneret), the orifice is a bundle of very small holes (typically 5-25 microns in diameter for E-glass and 9 microns for S-glass).These filaments are then sized (coated) with a chemical solution.Individual filaments are now bundled in large numbers to provide roving.The diameter of the filament and the number of filaments in the roving determine its weight, usually expressed in one of two measurement systems:
Yield, or yards per pound (yards of fiber in one pound of material; therefore lower numbers mean heavier rovings).Examples of standard yields are 225 yields, 450 yields, 675 yields.
Tex,or grams per kilometer (1 kilometer of roving weighs in grams, reversed from production; therefore a lower number means lighter roving). Examples of standard tex are 750tex,1100tex,2200tex.
These rovings are then used directly in composites applications such as pultrusion,filament winding (tubing), gun roving (automatic guns cut glass into shorter lengths and place them in a resin jet that is sprayed onto the mold surface ),or in an intermediate step, fabrics such as chopped strand mat (CSM) (made from randomly oriented fibers of small cut lengths all bonded together),woven,knitted or unidirectional fabrics.
Chopped strand mat
Chopped Strand Mat or CSM is a glass fiber reinforced material. It consists of randomly placed glass fibers held together by adhesives.It is usually processed using the hand lay-up technique, where sheets of material are placed on a mold and brushed with resin.Because the binder dissolves in the resin,the material easily takes on different shapes when wet.Once the resin has cured,the hardened product can be removed from the mold and finished.Using chopped strand mat to impart isotropic in-plane material properties to glass fibers.
The most commonly used type of glass fiber in glass fiber is alkali-free glass, that is,aluminoborosilicate glass with an alkali metal oxide content of less than 1% w/w,which is mainly used in FRP.Other types of glass used are A glass (soda lime glass with little or no boron oxide),E-CR glass (electrical/chemical resistant; aluminum with alkali metal oxide content less than 1% w/w Lime-silicate,with high acid resistance), C-glass (soda lime glass with high boron oxide content,used for short glass fibers and insulation),D-glass (borosilicate glass, derived from low dielectric constant name),R-glass (silicate glass without aluminum with high mechanical requirements of MgO and CaO as reinforcement) and S-glass (aluminosilicate glass with high MgO content but without CaO but high tensile strength Glass).Pure silica (silicon dioxide) can be used as glass fiber when cooled as fused silica to form glass with no true melting point,but has the disadvantage of having to work at very high temperatures.To lower the necessary operating temperature,other materials are introduced as "fluxing agents" (ie,ingredients that lower the melting point).Ordinary A glass (the "A" stands for "soda lime") or soda lime glass, which is crushed and ready to be remelted,is known as cullet,and it was the first type of glass used in fiberglass. E-glass ("E" derived from the original electrical application) is alkali-free and was the first glass formulation for continuous filament formation.It now accounts for the majority of the world's glass fiber production and is the world's largest consumer of the boron mineral.It is susceptible to chloride ion attack and is not suitable for marine applications.S-glass is used when tensile strength (high modulus) is important (“S” stands for “stiff”) and is therefore an important building and aircraft epoxy composite (known as R-glass in Europe," "R" stands for "reinforced"").C glass ("C" stands for "chemical resistance") and T glass ("T" stands for "thermal insulator"a North American variant of C glass) resists chemical attack;both Often found in insulation grade blown fiberglass media.
1.Polyester resin (unreinforced)
2.Polyester and chopped strand laminated 30% E-glass
3.Polyester and woven roving laminated to 45% E-glass
4.Polyester and satin laminated 55% E-glass
5.Polyester and continuous roving laminated to 70% E-glass
6.Alkali-free glass epoxy composite material
7.S-glass epoxy composites.