Is Fiberglass Conductive? And Other Common Questions About FRP
by Tencom Ltd.
Pultruded fiberglass has earned its place as one of the most versatile construction materials in the world. Its low cost and unique blend of advantages allows it to successfully replace traditional materials like wood, aluminum, and steel.
In fact, fiberglass outperforms many such substances in terms of strength, weight, and other important properties.
Despite its ubiquitous presence in the modern world, however, pultruded fiberglass still remains something of a mystery to many people.
If you would like to get your facts straight on fiberglass, and what it can do for you, keep reading.
This article provides clear answers to some of the most frequent questions asked about pultruded fiberglass.
What Is Pultruded Fiberglass?
Pultruded fiberglass — hereafter referred to simply as fiberglass — is a unique structural material combining fiber reinforcements and thermosetting resins.
Pultrusion refers to the process by which fiberglass is made. This process involves either drawing the fibers through a special resin bath, or injecting the fibers with resin.
Once the fiber has been wetted, machines shape it to the specified dimensions and then pull it into a preheated steel die.
The heat causes the resin to cure as it is pulled through the die. In this manner, fiberglass can be pultruded according to virtually any specification or shape, including sheets, rods, poles, angles, bars, and channels.
The only real limitation is that the pultruded fiberglass must has a constant cross-section.
Is Pultruded Fiberglass the same as Fiberglass Composite?
A frequent source of confusion about fiberglass has to do with the various naming conventions used.
Aside from "fiberglass" and "pultruded fiberglass," manufacturers may also use any of the following terms:
- Fiberglass Composite
- Glass-Reinforced Plastic (GRP)
- Fiber-Reinforced Plastic (FRP)
The good news is that all of these names refer to virtually the same thing: a composite constructed using two materials: fiber and resin.
The fiber provides reinforcement, while the resin provides the body — technically speaking, the matrix — necessary to give the product shape.
The main distinction to be aware of when it comes to fiberglass is the production method.
While most fiberglass structural components are manufactured by means of the pultrusion process discussed above, fiberglass may also be manufactured by means of compression molding, resin transfer molding, open-mold sprayup, and casting.
For this reason, pultrusion-based manufacturers often make a point of referring to their product specifically as pultruded fiberglass, in order to avoid confusion with fiberglass produced by other methods.
What Is Resin Made Of?
Resin is the ingredient most likely to vary from one type of fiberglass to another. Historically, three main types of resin have been used in fiberglass pultrusion:
- Vinyl Ester
Polyester remains the most widely utilized resin. While it does not excel in any one category, it offers a great overall blend of properties, being relatively low cost, easy to process, quick to cure, and relatively strong.
Vinyl ester is somewhat more costly than polyester, but results in a more durable fiberglass.
For the most part, vinyl ester has a molecular structure much like that of polyester. The difference is that vinyl esters contain fewer ester groups.
This gives the fiberglass a significantly greater degree of resistance to water and chemical corrosion.
Epoxy-based fiberglass demonstrates even greater durability, strength, and chemical resistance. In addition, epoxy increases the fiberglass' resistance to high temperatures.
That said, epoxy has more complex processing needs, and also tends to carry a higher material cost.
Finally, many pultruded fiberglass manufacturers have begun using polyurethane resin in recent years.
While polyurethane does present certain challenges from an equipment standpoint, its performance characteristics are second to none.
Polyurethane has been shown to outperform other resin types in terms of strength, toughness, and resistance to heat, ultraviolet light, and environmental factors.
Is Fiberglass Conductive?
Conductivity may refer to two different things: thermal conductivity and electrical conductivity.
Virtually all materials display some degree of thermal conductivity — in other words, allowing heat to move through them. That said, fiberglass tends to have a relatively low thermal conductivity, especially compared to metal.
Electrical conductivity is defined as the ability of a material to transmit electrical charge. Metals such as steel, copper, and aluminum all exhibit different degrees of electrical conductivity.
Fiberglass, by contrast, is generally categorized as being a non-conductive material, one that can even be successfully used as an electrical insulator.
Fiberglass thus holds a distinct advantage over metals in cases where conductivity must be strictly prohibited.
However, in certain situations conductivity may be a desirable trait. In those cases, manufacturers can often integrate additional composite materials to give the fiberglass a degree of conductivity.
For instance, aluminum fibers be introduced along with the glass fibers when pultruding the fiberglass.
Does Fiberglass Block Electromagnetic Waves?
As the modern world comes increasingly to rely on wireless communications technology, traditional building materials must be re-evaluated in terms of their effect on electromagnetic signals.
Common materials such as concrete, steel, and aluminum all exhibit significant inhibiting effects when it comes to electromagnetic waves.
Basically, any material that is either magnetic or electrically conductive will block or distort a significant amount of the wireless signals it encounters. Fortunately, fiberglass is neither magnetic nor electrically conductive.
As a result, fiberglass is for the most part transparent to radio waves, cellular frequencies, and other forms of electromagnetic signals.
For this reason, fiberglass has gained a significant amount of traction within the telecommunications industry.
In particular, fiberglass has become a material of choice when it comes to erecting cell tower screens. Likewise, fiberglass makes a great choice as a protective covering for antennas and other telecommunications equipment.
Pultruded fiberglass offers a wealth of benefits that make it one of the strongest, most durable, and most cost-effective building materials currently available.
If the idea of structural fiberglass is still new to you, don't worry. Savvy manufacturers know just how to design the custom fiberglass to meet virtually any need.
To learn more about the different types of fiberglass products they can manufacture for you, please do not hesitate to reach out to the industry leaders at Tencom Ltd.