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Fiberglass

Fiberglass , (also called fibreglass and glassfibre ), is material made from extremely finefibers of glass .

It is used as a reinforcing agent for manypolymer products; the resulting compositematerial , properly known as fiber-reinforcedpolymer (FRP) or glass-reinforced plastic (GRP), is called "fiberglass" in popular usage.
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Bundle of Fibre glass
http://upload.wikimedia.org/wikipedia/commons/e/e2/Glasfaser_Roving.jpg

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The types of fiberglass most commonly used are mainlyE-glass (alumino-borosilicate glass with less than 1 wt%

alkali oxides, maily used for glass-reinforced plastics), A-glass(alkali-lime glass with little or no boron oxide).

C-glass (alkali-lime glass with high boron oxide content, D-glass (borosilicate glass), R-glass (alumino silicate glasswithout MgO and CaO with high mechanical requirements),and S-glass (alumino silicate glass without CaO but with highMgO content with high tensile strength).
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PropertiesBy trapping air within them, blocks of glass fibermake good thermal insulation , with a thermalconductivity of the order of 0.05 W /(mK).The freshest, thinnest fibers are the strongest becausethe thinner fibers are more ductile.Humidity is an important factor in the tensilestrength. Moisture is easily adsorbed , and can worsenmicroscopic cracks and surface defects.
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In contrast to carbon fiber , glass can undergo moreelongation before it breaks.The viscosity of the molten glass is very important

for manufacturing success.During drawing (pulling of the glass to reduce fibercircumference), the viscosity should be relativelylow.

If it is too high, the fiber will break during drawing.However, if it is too low, the glass will form dropletsrather than drawing out into fiber.
http://en.wikipedia.org/wiki/Carbon_fiberhttp://en.wikipedia.org/wiki/Carbon_fiberhttp://en.wikipedia.org/wiki/Carbon_fiberhttp://en.wikipedia.org/wiki/Carbon_fiber

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Glass-reinforced plasticGlass-reinforced plastic (GRP) is a compositematerial or fiber-reinforced plastic made of a plastic reinforced by fine glass fibers.Uses of regular fiberglass include mats, thermalinsulation , electrical insulation , reinforcement of various materials, tent poles, sound absorption, heat-and corrosion-resistant fabrics, high-strength fabrics,pole vault poles, arrows, bows and crossbows,translucent roofing panels, automobile bodies andboat hulls.
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Mineral wool

Mineral wool , also known as mineral fibres orman-made mineral fibres are fibres made fromnatural or synthetic minerals or metal oxides.

The latter term is generally used to refer solely tosynthetic materials including fibreglass , ceramic fibres and rock or stone wool .Industrial applications of mineral wool includethermal insulation , filtration , soundproofing , andgermination of seedlings .
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ManufactureStone wool is a furnace product of molten rock at atemperature of about 1600 C, through which a streamof air or steam is blown.More advanced production techniques are based onspinning molten rock on high speed spinning wheels somewhat like the process used to prepare cottoncandy .

The final product is a mass of fine, intertwined fiberswith a typical diameter of 6 to 10 micrometers . Mineralwool may contain a binder , often food grade starch ,and an oil to reduce dusting .
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UsageThough the individual fibres conduct heat very well,when pressed into rolls and sheets their ability topartition air makes them excellent heat insulators andsound absorbers .Though not immune to the effects of a sufficientlyhot fire, the fire resistance of fibreglass , stone wooland ceramic fibres makes them common building

materials when passive fire protection is required.
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Mineral wools are unattractive to rodents but willprovide a structure for bacterial growth if allowed tobecome wet.Other uses are in filler in compounds for gaskets,brake pads, in plastics in the automotive industry andas a filtering medium.

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Safety of materialPrecautions need to be taken when handling a fibreproduct as it can be absorbed into the body by

inhalation.It can also irritate the eyes , skin and respiratory tract .Prolonged exposure could lead to long term effects.
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Common insulation applications inan apartment building .
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Fibre-reinforced plastic

Fibre-reinforced plastic (FRP ) (also fibre-reinforced polymer ) are composite materials made of

a polymer matrix reinforced with fibres.The fibers are usually fiberglass , carbon , or aramid ,while the polymer is usually an epoxy , vinylester orpolyester thermosetting plastic .FRPs are commonly used in the aerospace,automotive, marine, and construction industries.
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Fiber reinforced plastics are a category of composite plastics that specifically use fibrousmaterials to mechanically enhance the strength

and elasticity of plastics.The original plastic material without fiberreinforcement is known as the matrix. Thematrix is a tough but relatively weak plasticthat is reinforced by stronger stiffer reinforcingfilaments or fibers.
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The extent that strength and elasticity are enhanced ina fiber reinforced plastic depends on the mechanicalproperties of both the fiber and matrix, their volume

relative to one another, and the fiber length andorientation within the matrix.Reinforcement of the matrix occurs by definitionwhen the FRP material exhibits increased strength orelasticity relative to the strength and elasticity of thematrix alone.

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Process description

FRP involves two distinct processes, the first isthe process whereby the fibrous material ismanufactured and formed, the second is theprocess whereby fibrous materials are bondedwith the matrix during the molding process.

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Wet layupFiber reinforcing fabric is placed in an open mouldand then saturated with a wet [resin] by pouring itover the fabric and working it into the fabric andmould.The mould is then left so that the resin will cure,usually at room temperature, though heat issometimes used to ensure a proper curing process.

Glass fibers are most commonly used for this process,the results are widely known as fiberglass, and is usedto make common products like skis, canoes, and surf boards.

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Advantages and limitationsFRP allows the alignment the glass fibers of thermoplastics to suite specific design programs.Specifying the orientation of reinforcing fibers canincrease the strength and resistance to deformation of the polymer.Glass reinforced polymers are strongest and mostresistive to deforming forces when the polymers

fibers are parallel to the force being exerted, and areweakest when the fibers are perpendicular. Thus thisability is at once both an advantage or a limitationdepending on the context of use.

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Failure modesStructural failure can occur in FRP materials when:Tensile forces stretch the matrix more than the fibers, causingthe material to shear at the interface between matrix and fibers.Tensile forces near the end of the fibers exceed the tolerancesof the matrix, separating the fibers from the matrix.Tensile forces can also exceed the tolerances of the fiberscausing the fibers themselves to fracture leading to material

failure.

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Design considerationsFRP is used in designs that require a measure of strength ormodulus of elasticity that non-reinforced plastics and othermaterial choices are either ill suited for mechanically oreconomically.This means that the primary design consideration for usingFRP is to ensure that the material is used economically and ina manner that takes advantage of its structural enhancementsspecifically.This is however not always the case, the orientation of fibersalso creates a material weakness perpendicular to the fibers.

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Gypsum

Gypsum Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemicalformula CaSO42 H2O
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Uses of Gypsum Gypsum Board primarily used as a finish for walls andceilings; known in construction slang as Drywall Plaster ingredient.A component of Portland cement used to prevent flash settingof concreteA Binder in Fast-Dry tennis court clay.Plaster of Paris (surgical splints; casting moulds; modeling).
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Plasterof Paris

The term plaster can refer to plaster of Paris,lime plaster , or cement plaster .Plaster of Paris is a type of building materialbased on calcium sulphate hydrate , nominallyCaSO4H2O.It is created by heating gypsum to about

150 C.2 CaSO42H2O 2 CaSO40.5H2O + 3 H2O(released as steam).
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Large gypsum deposit at Montmartre in Paris is the source of the name.When the dry plaster powder is mixed with water, it re-forms

into gypsum. Plaster is used as a building material similar to

mortar or cement .Like those materials plaster starts as a dry powder that is

mixed with water to form a paste which liberates heat and thenhardens.Unlike mortar and cement , plaster remains quite soft afterdrying, and can be easily manipulated with metal tools or evensandpaper .These characteristics make plaster suitable for a finishing,rather than a load-bearing material.
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Because Plaster of Paris sets quickly, "retardants" were

used to slow setting time enough to allow workers tomix large working quantities of lime putty plaster.

Use in architecture Plaster may also be used to create complex detailingfor use in room interiors.

These are also often used to simulate wood or stonedetailing found in more substantial buildings.

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