Everything You Need To Know To Find The Best is fiberglass natural or synthetic

Composites are common in all industries. These materials consist of two separate components, each with different physical and chemical properties. When you combine these components, you can create a stronger and more advanced material than they would by themselves.

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You can find composites in a wide range of applications, from bridges to household appliances like microwaves. One notable example of a composite is fiberglass. This durable material is known for its malleability and durability, making it a popular choice for many industries and applications.

Read on to learn more about composite materials and fiberglass composites.

What Is a Composite Material?

Composite materials are combinations of two components. The two materials have different chemical and physical properties, creating a stronger material when combined. Both contribute their best attributes to form a specialized product.

Composites improve the qualities of their base materials. In most cases, manufacturers design composites with a specific use in mind. You could fashion a composite with enhanced strength or resistance to electricity.

Due to their durability and cost-efficiency, composites are popular in a wide range of industries. They can consist of both natural and synthetic materials. Here are some common examples of composite materials:

• Engineered wood: Engineered wood is a common material for many construction projects and building materials. This composite consists of real wood and adhesives, with the resulting products becoming more durable than regular wood pieces. You could also add capabilities like water resistance. Products like plywood and particleboard are examples of engineered wood.
• Reinforced concrete: Another notable composite is reinforced concrete, which contains concrete and steel bars. The reinforced steel typically has higher tensile strength, creating a more durable material overall. Reinforced concrete provides advanced strength for buildings and other structures.
• Plastic-coated paper: This composite combines plastic with paper to create a tougher material. For instance, playing cards typically contain this composite.
• Reinforced plastics: These materials feature a polymer matrix and reinforced fibers of glass, carbon or other components. Fiber-reinforced polymers are common in industries like aerospace and construction.

How Are Composites Formed?

You can form composites with a variety of techniques, including:

• Compression molding: In this method, you place a combination of materials into a preheated mold. You close the mold and hold it under pressure until the resin cures.
• Injection molding: This technique is similar to compression molding, but you inject the materials instead.
• Wet lay-up: For this technique, you build your initial component in a mold. Then, you apply additional reinforcement and wet resin layers until you reach the thickness you need for your composite.

Benefits of Composites

Composites are a popular selection for many applications. From electrical equipment to aerospace products or wall panels, you can find composite materials in many aspects of everyday life.

People choose composites over standalone materials for their many benefits, such as:

• Cost-efficiency: Composites provide a more cost-effective manufacturing method than other materials like metals. You mold them precisely, not allowing for any wasted materials or costs. Composites can also have lower costs per volume because they have less weight and overall volume. Using composites can also help you reduce expenses in other ways. For instance, a car featuring composite materials could be more lightweight and lead to better fuel efficiency.
• Versatility: You can combine a wide range of materials to form composites. And you can use composite materials to create specific shapes, products, designs and more. Their versatility makes them an excellent choice for many industries, products and applications.
• Durability: One of composites’ most notable benefits is their durable nature. By combining two features, you can create a stronger material overall. They can maintain their structure even in fatiguing environments, and their strength allows them to withstand heavy loads and harsh conditions. Many composites also require little maintenance, meaning they can maintain a high-quality condition without much additional help.
• Other enhanced capabilities: Composites can also have advanced features that make them even more useful. Many composites have corrosion-resistant properties. Even in harsh weather, the materials resist wear and rust formation, maintaining their strength. Composites could also have electrical insulation, fire resistance or waterproofing.

History of Composites

Manufacturers have used composites for centuries, which shows their useful and valuable nature. Here are some critical moments in the developmental history of composites:

• Ancient times: Composites originated thousands of years ago, when people started using them in daily applications. Many historians credit the first use of composites to the Mesopotamians around B.C., when they created plywood. They glued wood together at specific angles and realized this construction was more durable than a single piece of wood. Egyptians and Mesopotamians also combined straw with other products like pottery. Many builders and artisans used a variety of composites throughout the ancient period.
• Early to mid-s: Once we reached the early s, new chemical advances allowed for the creation of plastic. In , Dr. Leo Bakeland created the first synthetic plastic. This plastic material was reinforced with resin and formaldehyde, making it a notable composite. Then, Hermann Staudinger proved the existence of polymers in . Composite manufacturing developed even further with the production of the Chevrolet Corvette, which featured a composite-based body made up of fiberglass-reinforced plastic.
• Late s to s: The late s and early s also saw more composite developments. Composites became more popular for tools like poles, insulators, vehicles, small appliances and electrical infrastructures. Researchers and scientists are still completing composite research today. The modern age tends to be more interested in environmentally friendly products, so composites that meet these needs will likely grow in popularity.

Each type of composite comes with its own rich history. One example is fiberglass, invented first as a “glass wool” in the early s by Games Slayter. Manufacturing advancements made the material more versatile, and now we see fiberglass in a range of applications today.

What Is Fiberglass Made Of?

Fiberglass is made from a combination of glass fibers and polyester resins — it’s not carbon fiber. The resin reinforces the glass shards, creating a strong and lightweight consistency. During construction, manufacturers flatten the glass fibers into a sheet, weave them into fabric or use another strategy. You can add different resin types to the composite to make it less brittle and tougher. Vinyl ester is a particular example of polyester resin that can enhance corrosion resistance.

In most ways, fiberglass acts like regular glass — it doesn’t absorb moisture or form rust. You can also mold fiberglass into desired shapes and designs. Its malleability makes it a strong choice for a wide range of products, from bathtubs to boats. You can sell fiberglass as a raw material or use it in manufacturing to create other products. Some manufacturers use an additional gel coating to reinforce fiberglass further.

Types of Fiberglass

Fiberglass is available in a variety of thicknesses, strengths and materials. Manufacturers categorize fiberglass into different types based on their properties and glass orientation.

Here are some examples of the major types of fiberglass:

• A-glass: This type of fiberglass is also called alkali glass. It has many similarities to the glass used in windows. A-glass is an ideal option for manufacturers due to its chemical resistance, low cost and durability. It resists chemicals and maintains its structure after exposure, making it an excellent material for many applications. In some areas, manufacturers use A-glass in processing equipment. It’s also common in food containers, like jars and bottles.
• C-glass: C-glass is also referred to as chemical glass. This fiberglass type has the highest resistance against chemical impacts. Its structure gives it maximum protection against corrosion and other harmful chemical reactions. Because of its durability, manufacturers and engineers use C-glass in chemically exposed environments. You can find C-glass in the outer layers of pipes or chemical tanks.
• E-glass: E-glass is also known as electrical glass. It has a lightweight consistency and excels at insulating electricity. E-glass can also resist heat and maintain its strength in a variety of different conditions. These properties make it a strong choice for applications in aerospace, marine and industrial applications.
• S-glass: S-glass is also called structural glass. This glass type has extreme tensile and acidic strength. Due to its high strength levels, manufacturers develop this type for the defense and aerospace industries. However, S-glass is typically produced less often than other types, making it a more expensive option.

In addition to these types, fiberglass is available in different physical forms, including:

• Tape: Fiberglass tape consists of glass fiber yarns. This option has excellent thermal insulation. You can use fiberglass tape in a variety of applications, but many use it as reinforcement material. You could apply fiberglass tape to a hole in drywall or to reinforce seams in a boat.
• Cloth: Fiberglass cloth has a smooth consistency. Manufacturers often use it in heat shielding applications, such as fire curtains.
• Rope: Fiberglass rope is a useful material for many industries. Manufacturers braid glass fiber yarns into a rope structure. It’s used for packing and securing items.

Is Fiberglass a Composite or a Polymer?

Due to its construction, fiberglass is known as a composite material. As mentioned, composites form when two separate materials combine and form a more enhanced product. Fiberglass consists of glass shards and polyester resin, and when these two are molded together, it creates a stronger and improved material.

Fiberglass composites provide more advanced capabilities than just glass or resin alone. For instance, the material becomes more lightweight and has electrical insulation properties.

Overall, fiberglass is an extremely popular composite for many products and applications, from aerospace vehicles to roofing panels.

What Is Fiberglass Used For?

Fiberglass’s many beneficial properties make it a frequent choice in many industries. Its durability, thermal insulation and malleability are ideal for a wide range of applications.

Here are examples of common industries that use fiberglass:

• Manufacturing: You can use fiberglass in many manufacturing applications. It’s often featured in industrial machinery. Fiberglass provides strong insulation for the equipment, conserving its energy. You can also find fiberglass in production areas, like in grating materials, ladders and railings. Its consistency provides slip resistance in wet areas or places where oils are present, which can protect employees in these situations.
• Automotive industry: Fiberglass is also extremely common in the automotive industry. Many structural elements in cars consist of fiberglass, from bumpers and hoods to body kits. It’s also frequently used in belts due to its solid structural composition. Manufacturers often choose fiberglass over other typical materials like aluminum because of its lightweight nature and low cost.
• Pulp and paper: Fiberglass is popular in the pulp and paper industries because of its corrosion resistance. You can use fiberglass materials in pulping areas, where it protects against slips. It’s also common in paper machines and stock preparation areas, which are crucial to paper construction.
• Food and beverage industries: Fiberglass has many uses in the food and beverage industries. It’s an excellent option for food storage, like jars. It resists chemicals and protects food and drinks while not in use. You can also find fiberglass in food processing locations, where it serves as a grating material.
• Fountains and aquariums: Fountains and aquariums often use fiberglass in their designs. Fiberglass withstands chemical processes in water-based environments, such as disinfection. In addition, fiberglass can support rocks in water tanks, allowing water to circulate and filter properly. You can also use fiberglass grating in sprayers, light fixtures and other structural elements in aquariums. The material protects these structures from forming rust.

Benefits of Fiberglass

Countless industries have found uses for fiberglass. Its notoriety is because of benefits like:

• High strength levels: Fiberglass won’t rust, degrade or weaken in harsh conditions. It maintains its integrity in a variety of environments, keeping up its high-performance qualities. In turn, industries of all types can use the composite for long-term applications.
• Customization abilities: The material can easily mold into desired shapes, making it ideal for unique applications. With its malleability, fiberglass helps reduce the need for secondary finishes or extra processing. You can create products that meet individual needs, no matter your industry.
• Sound absorbency: Fiberglass also contains sound absorption properties. You can reduce the noise levels of machinery, lowering the risk of hearing damage.
• Cost-efficiency: Fiberglass is an economical choice for any industry. Its long service life and low maintenance needs reduce the need for replacements. Using fiberglass can also minimize waste production because the materials last for extended periods.

Beef up Your Building With Fiberglass Panels From Stabilit America

Fiberglass is a popular composite material used around the world. Its durability and versatility make it an ideal choice for an endless number of applications.

At Stabilit America, we understand the necessity of high-quality materials. As a leading manufacturer of fiberglass-reinforced plastic panels, we provide durable and long-term solutions for a wide range of industries. Our fiber-reinforced plastic panels serve industrial, commercial and residential applications.

Fiberglass-reinforced panels can transform your facility, adding reinforced protection and an aesthetic appeal. We offer roofing, siding and liner panels to meet a variety of needs. Our materials are high-strength and corrosion-resistant, providing a long-term solution.

Type of plastic reinforced by glass fibre This article is about the type of composite material. For the thermal insulation material sometimes called fibreglass, see glass wool. For the glass fiber itself, also sometimes called fiberglass, see glass fiber.

Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth. The plastic matrix may be a thermoset polymer matrix—most often based on thermosetting polymers such as epoxy, polyester resin, or vinyl ester resin—or a thermoplastic.

Cheaper and more flexible than carbon fiber, it is stronger than many metals by weight, non-magnetic, non-conductive, transparent to electromagnetic radiation, can be molded into complex shapes, and is chemically inert under many circumstances. Applications include aircraft, boats, automobiles, bath tubs and enclosures, swimming pools, hot tubs, septic tanks, water tanks, roofing, pipes, cladding, orthopedic casts, surfboards, and external door skins.

Other common names for fiberglass are glass-reinforced plastic (GRP),[1] glass-fiber reinforced plastic (GFRP)[2] or GFK (from German: Glasfaserverstärkter Kunststoff). Because glass fiber itself is sometimes referred to as "fiberglass", the composite is also called fiberglass-reinforced plastic (FRP). This article uses "fiberglass" to refer to the complete fiber-reinforced composite material, rather than only to the glass fiber within it.

History

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Glass fibers have been produced for centuries, but the earliest patent was awarded to the Prussian inventor Hermann Hammesfahr (–) in the U.S. in .[3][4]

Mass production of glass strands was accidentally discovered in when Games Slayter, a researcher at Owens-Illinois, directed a jet of compressed air at a stream of molten glass and produced fibers. A patent for this method of producing glass wool was first applied for in .[5] Owens joined with the Corning company in and the method was adapted by Owens Corning to produce its patented "Fiberglas" (spelled with one "s") in . Originally, Fiberglas was a glass wool with fibers entrapping a great deal of gas, making it useful as an insulator, especially at high temperatures.

A suitable resin for combining the fiberglass with a plastic to produce a composite material was developed in by DuPont. The first ancestor of modern polyester resins is Cyanamid's resin of . Peroxide curing systems were used by then.[6] With the combination of fiberglass and resin the gas content of the material was replaced by plastic. This reduced the insulation properties to values typical of the plastic, but now for the first time, the composite showed great strength and promise as a structural and building material. Many glass fiber composites continued to be called "fiberglass" (as a generic name) and the name was also used for the low-density glass wool product containing gas instead of plastic.

Ray Greene of Owens Corning is credited with producing the first composite boat in but did not proceed further at the time because of the brittle nature of the plastic used. In the Soviet Union was reported to have constructed a passenger boat of plastic materials, and the United States a fuselage and wings of an aircraft.[7] The first car to have a fiberglass body was a prototype of the Stout Scarab, but the model did not enter production.[8]

Fiber

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Unlike glass fibers used for insulation, for the final structure to be strong, the fiber's surfaces must be almost entirely free of defects, as this permits the fibers to reach gigapascal tensile strengths. If a bulk piece of glass were defect-free, it would be as strong as glass fibers; however, it is generally impractical to produce and maintain bulk material in a defect-free state outside of laboratory conditions.[9]

Production

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The process of manufacturing fiberglass is called pultrusion. The manufacturing process for glass fibers suitable for reinforcement uses large furnaces to gradually melt the silica sand, limestone, kaolin clay, fluorspar, colemanite, dolomite and other minerals until a liquid forms. It is then extruded through bushings (spinneret), which are bundles of very small orifices (typically 5–25 micrometres in diameter for E-Glass, 9 micrometres for S-Glass).[10]

These filaments are then sized (coated) with a chemical solution. The individual filaments are now bundled in large numbers to provide a roving. The diameter of the filaments, and the number of filaments in the roving, determine its weight, typically expressed in one of two measurement systems:

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• yield, or yards per pound (the number of yards of fiber in one pound of material; thus a smaller number means a heavier roving). Examples of standard yields are 225yield, 450yield, 675yield.
• tex, or grams per km (how many grams 1 km of roving weighs, inverted from yield; thus a smaller number means a lighter roving). Examples of standard tex are 750tex, tex, tex.

These rovings are then either used directly in a composite application such as pultrusion, filament winding (pipe), gun roving (where an automated gun chops the glass into short lengths and drops it into a jet of resin, projected onto the surface of a mold), or in an intermediary step, to manufacture fabrics such as chopped strand mat (CSM) (made of randomly oriented small cut lengths of fiber all bonded together), woven fabrics, knit fabrics or unidirectional fabrics.

Chopped strand mat

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Chopped strand mat (CSM) is a form of reinforcement used in fiberglass. It consists of glass fibers laid randomly across each other and held together by a binder. It is typically 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 resin, the material easily conforms to different shapes when wetted out. After the resin cures, the hardened product can be taken from the mold and finished. Using chopped strand mat gives the fiberglass isotropic in-plane material properties.[citation needed]

Sizing

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A coating or primer is applied to the roving to help protect the glass filaments for processing and manipulation and to ensure proper bonding to the resin matrix, thus allowing for the transfer of shear loads from the glass fibers to the thermoset plastic. Without this bonding, the fibers can 'slip' in the matrix causing localized failure.[11]

Properties

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An individual structural glass fiber is both stiff and strong in tension and compression—that is, along its axis. Although it might be assumed that the fiber is weak in compression, it is actually only the long aspect ratio of the fiber which makes it seem so; i.e., because a typical fiber is long and narrow, it buckles easily.[9] On the other hand, the glass fiber is weak in shear—that is, across its axis. Therefore, if a collection of fibers can be arranged permanently in a preferred direction within a material, and if they can be prevented from buckling in compression, the material will be preferentially strong in that direction.

Furthermore, by laying multiple layers of fiber on top of one another, with each layer oriented in various preferred directions, the material's overall stiffness and strength can be efficiently controlled. In fiberglass, it is the plastic matrix which permanently constrains the structural glass fibers to directions chosen by the designer. With chopped strand mat, this directionality is essentially an entire two-dimensional plane; with woven fabrics or unidirectional layers, directionality of stiffness and strength can be more precisely controlled within the plane.

A fiberglass component is typically of a thin "shell" construction, sometimes filled on the inside with structural foam, as in the case of surfboards. The component may be of nearly arbitrary shape, limited only by the complexity and tolerances of the mold used for manufacturing the shell.

The mechanical functionality of materials is heavily reliant on the combined performances of both the resin (AKA matrix) and fibers. For example, in severe temperature conditions (over 180 °C), the resin component of the composite may lose its functionality, partially due to bond deterioration of resin and fiber.[12] However, GFRPs can still show significant residual strength after experiencing high temperatures (200 °C).[13]

One notable feature of fiberglass is that the resins used are subject to contraction during the curing process. For polyester this contraction is often 5–6%; for epoxy, about 2%. Because the fibers do not contract, this differential can create changes in the shape of the part during curing. Distortions can appear hours, days, or weeks after the resin has set. While this distortion can be minimized by symmetric use of the fibers in the design, a certain amount of internal stress is created; and if it becomes too great, cracks form.

Types

[edit] Main article: Glass fiber

The most common types of glass fiber used in fiberglass is E-glass, which is alumino-borosilicate glass with less than 1% w/w alkali oxides, mainly used for glass-reinforced plastics. Other types of glass used are A-glass (Alkali-lime glass with little or no boron oxide), E-CR-glass (Electrical/Chemical Resistance; alumino-lime silicate with less than 1% w/w alkali oxides, with high acid resistance), C-glass (alkali-lime glass with high boron oxide content, used for glass staple fibers and insulation), D-glass (borosilicate glass, named for its low Dielectric constant), R-glass (alumino silicate glass without MgO and CaO with high mechanical requirements as Reinforcement), and S-glass (alumino silicate glass without CaO but with high MgO content with high tensile strength).[14]

Pure silica (silicon dioxide), when cooled as fused quartz into a glass with no true melting point, can be used as a glass fiber for fiberglass but has the drawback that it must be worked at very high temperatures. In order to lower the necessary work temperature, other materials are introduced as "fluxing agents" (i.e., components to lower the melting point). Ordinary A-glass ("A" for "alkali-lime") or soda lime glass, crushed and ready to be remelted, as so-called cullet glass, was the first type of glass used for fiberglass. E-glass ("E" because of initial Electrical application), is alkali-free and was the first glass formulation used for continuous filament formation. It now makes up most of the fiberglass production in the world, and also is the single largest consumer of boron minerals globally. It is susceptible to chloride ion attack and is a poor choice for marine applications. S-glass ("S" for "stiff") is used when tensile strength (high modulus) is important and is thus an important building and aircraft epoxy composite (it is called R-glass, "R" for "reinforcement" in Europe). C-glass ("C" for "chemical resistance") and T-glass ("T" is for "thermal insulator"—a North American variant of C-glass) are resistant to chemical attack; both are often found in insulation-grades of blown fiberglass.[15]

Table of some common fiberglass types

[edit] Material Specific gravity Tensile strength MPa (ksi) Compressive strength MPa (ksi) Polyester resin (Not reinforced)[16] 1.28 55 (7.98) 140 (20.3) Polyester and Chopped Strand Mat Laminate 30% E-glass[16] 1.4 100 (14.5) 150 (21.8) Polyester and Woven Rovings Laminate 45% E-glass[16] 1.6 250 (36.3) 150 (21.8) Polyester and Satin Weave Cloth Laminate 55% E-glass[16] 1.7 300 (43.5) 250 (36.3) Polyester and Continuous Rovings Laminate 70% E-glass[16] 1.9 800 (116) 350 (50.8) E-Glass Epoxy composite[17] 1.99 1,770 (257) S-Glass Epoxy composite[17] 1.95 2,358 (342)

Applications

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Fiberglass is versatile because it is lightweight, strong, weather-resistant, and can have a variety of surface textures.[18]

During World War II, fiberglass was developed as a replacement for the molded plywood used in aircraft radomes (fiberglass being transparent to microwaves). Its first main civilian application was for the building of boats and sports car bodies, where it gained acceptance in the s. Its use has broadened to the automotive and sport equipment sectors. In the production of some products, such as aircraft, carbon fiber is now used instead of fiberglass, which is stronger by volume and weight.

Advanced manufacturing techniques such as pre-pregs and fiber rovings extend fiberglass's applications and the tensile strength possible with fiber-reinforced plastics.

Fiberglass is also used in the telecommunications industry for shrouding antennas, due to its RF permeability and low signal attenuation properties. It may also be used to conceal other equipment where no signal permeability is required, such as equipment cabinets and steel support structures, due to the ease with which it can be molded and painted to blend with existing structures and surfaces. Other uses include sheet-form electrical insulators and structural components commonly found in power-industry products. Because of fiberglass's lightweight and durability, it is often used in protective equipment such as helmets. Many sports use fiberglass protective gear, such as goaltenders' and catchers' masks.[19]

Storage tanks

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Storage tanks can be made of fiberglass with capacities up to about 300 tonnes. Smaller tanks can be made with chopped strand mat cast over a thermoplastic inner tank which acts as a preform during construction. Much more reliable tanks are made using woven mat or filament wound fiber, with the fiber orientation at right angles to the hoop stress imposed in the sidewall by the contents. Such tanks tend to be used for chemical storage because the plastic liner (often polypropylene) is resistant to a wide range of corrosive chemicals. Fiberglass is also used for septic tanks.

House building

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Glass-reinforced plastics are also used to produce house building components such as roofing laminate, door surrounds, over-door canopies, window canopies and dormers, chimneys, coping systems, and heads with keystones and sills. The material's reduced weight and easier handling, compared to wood or metal, allows faster installation. Mass-produced fiberglass brick-effect panels can be used in the construction of composite housing, and can include insulation to reduce heat loss.

Oil and gas artificial lift systems

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In rod pumping applications, fiberglass rods are often used for their high tensile strength to weight ratio. Fiberglass rods provide an advantage over steel rods because they stretch more elastically (lower Young's modulus) than steel for a given weight, meaning more oil can be lifted from the hydrocarbon reservoir to the surface with each stroke, all while reducing the load on the pumping unit.

Fiberglass rods must be kept in tension, however, as they frequently part if placed in even a small amount of compression. The buoyancy of the rods within a fluid amplifies this tendency.

Piping

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GRP and GRE pipe can be used in a variety of above- and below-ground systems, including those for desalination, water treatment, water distribution networks, chemical process plants, water used for firefighting, hot and cold drinking water, wastewater/sewage, municipal waste and liquified petroleum gas.[citation needed]

Boating

[edit] Main article: Boat building § Fiberglass

Fiberglass composite boats have been made since the early s,[20] and many sailing vessels made after were built using the fiberglass lay-up process. As of , boats continue to be made with fiberglass, though more advanced techniques such as vacuum bag moulding are used in the construction process.[21]

Armour

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Though most bullet-resistant armours are made using different textiles, fiberglass composites have been shown to be effective as ballistic armor.[22]

Construction methods

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Filament winding

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Filament winding is a fabrication technique mainly used for manufacturing open (cylinders) or closed-end structures (pressure vessels or tanks). The process involves winding filaments under tension over a male mandrel. The mandrel rotates while a wind eye on a carriage moves horizontally, laying down fibers in the desired pattern. The most common filaments are carbon or glass fiber and are coated with synthetic resin as they are wound. Once the mandrel is completely covered to the desired thickness, the resin is cured; often the mandrel is placed in an oven to achieve this, though sometimes radiant heaters are used with the mandrel still turning in the machine. Once the resin has cured, the mandrel is removed, leaving the hollow final product. For some products such as gas bottles, the 'mandrel' is a permanent part of the finished product forming a liner to prevent gas leakage or as a barrier to protect the composite from the fluid to be stored.

Filament winding is well suited to automation, and there are many applications, such as pipe and small pressure vessels that are wound and cured without any human intervention. The controlled variables for winding are fiber type, resin content, wind angle, tow or bandwidth and thickness of the fiber bundle. The angle at which the fiber has an effect on the properties of the final product. A high angle "hoop" will provide circumferential or "burst" strength, while lower angle patterns (polar or helical) will provide greater longitudinal tensile strength.

Products currently being produced using this technique range from pipes, golf clubs, Reverse Osmosis Membrane Housings, oars, bicycle forks, bicycle rims, power and transmission poles, pressure vessels to missile casings, aircraft fuselages and lamp posts and yacht masts.

Fiberglass hand lay-up operation

[edit] Main article: Lay-up process

A release agent, usually in either wax or liquid form, is applied to the chosen mold to allow the finished product to be cleanly removed from the mold. Resin—typically a 2-part thermoset polyester, vinyl, or epoxy—is mixed with its hardener and applied to the surface. Sheets of fiberglass matting are laid into the mold, then more resin mixture is added using a brush or roller. The material must conform to the mold, and air must not be trapped between the fiberglass and the mold. Additional resin is applied and possibly additional sheets of fiberglass. Hand pressure, vacuum or rollers are used to be sure the resin saturates and fully wets all layers, and that any air pockets are removed. The work must be done quickly before the resin starts to cure unless high-temperature resins are used which will not cure until the part is warmed in an oven.[23] In some cases, the work is covered with plastic sheets and vacuum is drawn on the work to remove air bubbles and press the fiberglass to the shape of the mold.[24]

Fiberglass spray lay-up operation

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The fiberglass spray lay-up process is similar to the hand lay-up process but differs in the application of the fiber and resin to the mold. Spray-up is an open-molding composites fabrication process where resin and reinforcements are sprayed onto a mold. The resin and glass may be applied separately or simultaneously "chopped" in a combined stream from a chopper gun.[25] Workers roll out the spray-up to compact the laminate. Wood, foam or other core material may then be added, and a secondary spray-up layer imbeds the core between the laminates. The part is then cured, cooled, and removed from the reusable mold.

Pultrusion operation

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Pultrusion is a manufacturing method used to make strong, lightweight composite materials. In pultrusion, material is pulled through forming machinery using either a hand-over-hand method or a continuous-roller method (as opposed to extrusion, where the material is pushed through dies). In fiberglass pultrusion, fibers (the glass material) are pulled from spools through a device that coats them with a resin. They are then typically heat-treated and cut to length. Fiberglass produced this way can be made in a variety of shapes and cross-sections, such as W or S cross-sections.

Health hazards

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Exposure

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People can be exposed to fiberglass in the workplace during its fabrication, installation or removal, by breathing it in, by skin contact, or by eye contact. Furthermore, in the manufacturing process of fiberglass, styrene vapors are released while the resins are cured. These are also irritating to mucous membranes and respiratory tract.[26] The general population can get exposed to fibreglass from insulation and building materials or from fibers in the air near manufacturing facilities or when they are near building fires or implosions.[27]: 8  The American Lung Association advises that fiberglass insulation should never be left exposed in an occupied area. Since work practices are not always followed, and fiberglass is often left exposed in basements that later become occupied, people can get exposed.[28] No readily usable biological or clinical indices of exposure exist.[27]: 8 

Symptoms and signs, health effects

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Fiberglass will irritate the eyes, skin, and the respiratory system. Hence, symptoms can include itchy eyes, skin, nose, sore throat, hoarseness, dyspnea (breathing difficulty) and cough.[29] Peak alveolar deposition was observed in rodents and humans for fibers with diameters of 1 to 2 μm.[27]: 13  In animal experiments, adverse lung effects such as lung inflammation and lung fibrosis have occurred,[27]: 14  and increased incidences of mesothelioma, pleural sarcoma, and lung carcinoma had been found with intrapleural or intratracheal instillations in rats.[27]: 12 

As of , in humans only the more biopersistent materials like ceramic fibres, which are used industrially as insulation in high-temperature environments such as blast furnaces, and certain special-purpose glass wools not used as insulating materials remain classified as possible carcinogens (IARC Group 2B). The more commonly used glass fibre wools including insulation glass wool, rock wool and slag wool are considered not classifiable as to carcinogenicity to humans (IARC Group 3).[30] In October , all fiberglass wools commonly used for thermal and acoustical insulation were reclassified by the International Agency for Research on Cancer (IARC) as "not classifiable as to carcinogenicity to humans" (IARC group 3). "Epidemiologic studies published during the 15 years since the previous IARC monographs review of these fibers in provide no evidence of increased risks of lung cancer or mesothelioma (cancer of the lining of the body cavities) from occupational exposures during the manufacture of these materials, and inadequate evidence overall of any cancer risk."[30] In June , the US National Toxicology Program (NTP) removed from its Report on Carcinogens all biosoluble glass wool used in home and building insulation and for non-insulation products.[31] However, NTP still considers fibrous glass dust to be "reasonably anticipated [as] a human carcinogen (Certain Glass Wool Fibers (Inhalable))".[29] Similarly, California's Office of Environmental Health Hazard Assessment (OEHHA) published a November, modification to its Proposition 65 listing to include only "Glass wool fibers (inhalable and biopersistent)."[32] Therefore a cancer warning label for biosoluble fiber glass home and building insulation is no longer required under federal or California law. As of , the North American Insulation Manufacturers Association stated that fiberglass is safe to manufacture, install and use when recommended work practices are followed to reduce temporary mechanical irritation.[33]

As of , the European Union and Germany have classified synthetic glass fibers as possibly or probably carcinogenic, but fibers can be exempt from this classification if they pass specific tests.[30] A health hazard review for the European Commission stated that inhalation of fiberglass at concentrations of 3, 16 and 30 mg/m3 "did not induce fibrosis nor tumours except transient lung inflammation that disappeared after a post-exposure recovery period."[34] Historic reviews of the epidemiology studies had been conducted by Harvard's Medical and Public Health Schools in ,[35] the National Academy of Sciences in ,[36] the Agency for Toxic Substances and Disease Registry ("ATSDR") in ,[37] and the National Toxicology Program in .[38] which reached the same conclusion as IARC that there is no evidence of increased risk from occupational exposure to glass wool fibers.

Pathophysiology

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Genetic and toxic effects are exerted through production of reactive oxygen species, which can damage DNA, and cause chromosomal aberrations, nuclear abnormalities, mutations, gene amplification in proto-oncogenes, and cell transformation in mammalian cells. There is also indirect, inflammation-driven genotoxicity through reactive oxygen species by inflammatory cells. The longer and thinner as well as the more durable (biopersistent) fibers were, the more potent they were in damage.[27]: 14 

Regulation, exposure limits

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In the US, fine mineral fiber emissions have been regulated by the EPA, but respirable fibers (“particulates not otherwise regulated”) are regulated by Occupational Safety and Health Administration (OSHA); OSHA has set the legal limit (permissible exposure limit) for fiberglass exposure in the workplace as 15 mg/m3 total and 5 mg/m3 in respiratory exposure over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 3 fibers/cm3 (less than 3.5 micrometers in diameter and greater than 10 micrometers in length) as a time-weighted average over an 8-hour workday, and a 5 mg/m3 total limit.[39]

As of , the Hazardous Substances Ordinance in Germany dictates a maximum occupational exposure limit of 86 mg/m3. In certain concentrations, a potentially explosive mixture may occur. Further manufacture of GRP components (grinding, cutting, sawing) creates fine dust and chips containing glass filaments, as well as tacky dust,[definition needed] in quantities high enough to affect health and the functionality of machines and equipment. The installation of effective extraction and filtration equipment is required to ensure safety and efficiency.[26]

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See also

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• Bulk moulding compound
• Fiberglass sheet laminating
• G-10 (material)
• Glass fiber reinforced concrete
• Hobas
• Ignace Dubus-Bonnel
• Sheet moulding compound
• Carbon-fiber-reinforced polymers reinforcement with carbon fibers.

References

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