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FIBER PROPERTIES

Your guide to structural fibres

Fiber selection, a key component in our reinforcements

 

Factors governing properties of a composite structure

 

Basic mechanical properties of the fiber itself

Weave, i.e. the alignment of the fiber in the composite, the position, the fiber diameter, shape and coverage of the fibers which will influence the percentage of fiber in the composite.

Treatment and finish of the fiber surface (sizing) which influences the bonding of the fiber with the resin

Properties of the resin used, the percentage used in the laminate, the degree of bonding and the interaction with the fiber itself

Positioning of the fibers in relationship with the main load paths or the other sollicitations

 

Glass

Glass fiber is the most common composite reinforcement.

Fabric made of glass fibers is characterized by

  • High tensile strength
  • Dimensional stability
  • High heat and fire resistance
  • Resistance to many chemical compounds
  • Has electrical properties that make it useful in electronic components

 

Fibers made from glass are manufactured in different varieties for specific uses, including low dielectric, corrosion-resistant and high-strength varieties.
For specific applications please contact us.

Some common types of glass fibers.

 

E-Glass

Originally known as Electical glass

The most economical and commonly used fiber in the reinforced polymer composite industry.

Variety of sizes (finish) depending on the resin system process application.

Good overall strength properties

E-CR Glass

Corrosion Resistant

An E-glass with higher acid corrodion resistance.

Used where strength, electrical conductivity and acid corrosion resistance is needed.

S2®-Glass or HT Glass

Named ”S” for strength or HT for high tenacity

Used where high strength, high temperature resistance, and corrosive resistance are needed.

Density g/m³2.52.542.49
Tensile strengthGoodSimilar et E-glass40-50% Higher than E-glass
Compression strengthGoodSimilar to E-glass40-50% Higher than E-glass
Rigidity  10% Superior to E-glass
Heat resistanceGoodSlightly superior to E-glassSignificantly superior to E-glass (10-30%)

® Registered trademark AGY Holdings Corp.

 

Carbon

Carbon is a widely used fiber in high-performance applications, offering an astonishing range of properties.

 

Carbon fiber has a wide range of strength and stiffness. Carbon fiber is grouped into categories based on its modulus of elasticity and/or it’s strength— from regular to ultra-high modulus, from regular to ultra-high strength. Carbon provides exceptionally high properties in both tension and compression.

There are two principal types of carbon fibers:

 

PAN-based ((PAN: Polyacrylonitrile)

  • The most widely used reinforcement in high-performance applications
  • Characterized by a high tensile strength and high elastic modulus
  • Extensively applied for structural material composites in aerospace, industrial fields, military, civil engineering and competition sporting and recreational goods
  • There are multiple grade of PAN Based carbon, “standard high tenacity” as well high strength and High modulus

 

Pitch-based carbon fiber

  • More expensive and less commonly used than PAN-based carbon
  • Characterized by a lower tensile strength but a broader modulus range than the PAN based
  • Low to negative coefficient of thermal expansion (CET), making this carbon useful in highly specialized applications that require thermal management, such as high-performance braking systems and aerospace electronic instrument housings

PAN “standard HT” Carbon fiber as it compares to E-Glass

  Carbon fibre
Density g/cm³1.8
Strength and rigidity70-140% greater than glass
ModulusAs much as 400-500% higher than glass

 

Aramids

Aramid fibers have one of the highest strength to weight ratio compared to other commercially available fibers. Aramid fiber properties depend on the manufacturing process and can vary quite a lot depending on the intended end use.

 

There are two families of Aramids:

 

Para-aramids

  • Used in composites and protection weaves, tires, fiber optics
  • Better know by it’s trade names Kevlar® from Dupont Protection Technologies, Twaron® by Teijin Aramid BV and Heracron® by Kolon Industries
  • Available in both low- and high-modulus. (Kevlar® 29 and 49 respectively)
  • Characterized by it’s high tensile strength and modulus as well as the high-tensile-strength to weight ratio

 

Meta-aramids

  • Known as Nomex® from Dupont Protection Technologies, Teijinconex® by Teijin Limited
  • Has a lower modulus and tensile strength than the para-aramids, but excels thermally and chemically, withstanding temperatures
  • Ideally suited for use for thermal protection, e.g. in personal protective equipment or industrial filters
 Para-aramid
Density g/cm³1.44
Strength and rigidity70-140% greater than glass in tension
ModulusAs much as 200% higher than glass

Basalt

Basalt is a volcanic (igneous) rock that is quarried, crushed and melted, then extruded as fibers. Basalt has a chemical composition similar to glass, but what truly distinguishes it from glass is it’s high-melting point, allowing it to be exposed to high temperatures for extended periods of time.

 

It has the same coefficient of thermal expansion (CET) as concrete and is less susceptible to degradation in an alkaline environment, making it a new contender in infrastructure applications.

It’s heat-resistance and anti-corrosive properties also make it an ideal candidate for high-grade filtration systems.

 

It’s tensile strength and modulus have been demonstrated to be close to that of S2®-Glass, but as basalt fibers are less complex and time-consuming to produce, the cost is a lot less, putting the price of basalt  much closer to E-Glass than S2®-Glass.

 

® Registered trademark AGY Holdings Corp.

 

Comparison table to come

Natural fibers

Natural fibers are enjoying increased use because of their very low weight, excellent insulation properties, and their “green” attributes:

  • Energy efficiency
    expending up to 90% less energy in their production vs synthetic fibers
  • Sustainability
    biodegradable when disposed of and renewable via farming
  • Carbon dioxide neutrality
    When incinerated, natural fibers give off no more carbon dioxide than was originally consumed during lifetime of the fibers

 

Flax fibers are increasingly being used in composite structures, and hemp is positioned  to follow.

 

Characteristics of flax fibers

  • At a density of 1.4 gr/cm3, it has the lowest density of structural fibers
  • Distinguished by dampening properties that are far superior to glass and carbon making it ideal for acoustic and vibration/shock absorption applications i.e. transportation, sporting equipment
  • Similar specific tensile strength compared to E-Glass
  • Slightly superior specific modulus rating compared to E-Glass.
  • More appropriate for use in monolithic structures versus sandwich structures

 

 

Ongoing innovations in the harvesting and processing continues to improve performance and reduce costs of the bio-fibers, making them more and more commercially viable and better able to compete with synthetic-fiber products in terms of price and performance.

Innegra™ high-modulus polypropylene

At a density of 0.84, Innegra is the lightest fiber commercially available. It’s high flexibility and ductility makes it virtually ”unbreakable”. It is commonly used in combination with other fibres (primarily glass, basalt, carbon) to expand the performance of existing materials by reducing brittleness, damage tolerance and puncture resistance. Remains white when laminated.

It is a good economical candidate for increased thickness with a fairly low weight and improved toughness.

It is also a good candidate for low dielectric constant

 

Innegra™ is a trademark of Innegra Technologies, LLC

 

Polyester

A light, economical fiber that is stiffer than Innegra™ and can improve resistance to perforation.

 

  • Like Innegra™, polyester is light with a density of 1.3 g/cm3
  • Available in different colors
  • Average adhesion to resin
  • Performs poorly against compression

 

It is a good economical candidate for increased thickness with a fairly low weight and improved toughness.

 

Hybrids

When the properties required by a specific application seem to be at odds with one another,

a hybrid weave may provide the answer — by allowing you to benefit from the combined properties of the different structural fibers used in it’s fabrication.

 

Creating real-world solutions by deriving the full benefits of the individual fibres and their synergistic responses comes from our deep understanding and experience in structural composites, materials and weaves.

 

 

Aramid/Glass

 

Provides a lower density, thicker skin for the same weight and greater stiffness than glass alone which can translate into weight saving and puncture /impact improvement compare to 100% glass.

 

 

Carbon/Innegra™

 

Marrying the stiffness and relative brittleness of carbon to the high-ductility and pliability of polypropylene, the different fiber properties complement each other for exceptional impact and perforation resistance —  providing better material integrity as compare to traditional composites rupture mode (does not fully break, ductile mode of rupture)

 

Basalt/ Innegra™ and Glass/ Innegra™

 

Providing a semi-ductile performance, these hybrids are some of the best reinforcements against severe impact—It’s maximum energy absorption offers protection from catastrophic ruptures (does not fully break, ductile mode of rupture) while at the same time providing an acceptable tensile strength and static stiffness.

Innegra™ is a trademark of Innegra Technologies, LLC

 

Thermoplastics comingle

For over 30 years, Texonic (formerly known as JB Martin) has been at the vanguard in weaving commingled thermoplastic and reinforcing fibers. Once woven, the fabric is suitable for use in various molding processes. It is by heating the material above the melting point of the matrix that the fabric is converted into composites.

 

Thermoplastic composites have an increased impact resistance to comparable thermoset composites. In some instances, the difference is significantly higher impact resistance.

PEEK — Polyetheretherketone

PEI — Polyetherimide

PPS — Polyphenylene Sulfide

High stiffness, high temperature resistance

PA -12 — Polyamide

Good mechanical properties, requiring lower molding temperatures

PP-Polypropylene

For lightweight, highly ductile performance for applications requiring low stiffness yet high-impact resistance i.e. transportation, sport and leisure products, luggage, high performance packaging.

Both Compofil™-PP by Jushi USA and TWINTEX® (previously produced by Vetrotex) have made this a cost-effective choice.

Comparison Charts

Basic mechanical properties
of commonly used structural fibers

 Tensile strength (KSI)Specific strengthTensile rigidity (MSI)Specific rigidityElongation at break % A%Density
E-Glass42016510.54.134.42.54
S-2 Glass66526712.44.985.22.49
Basalt60022712.34.6632.64

Aramid: High Modulus

(Dupont ™ Kevlar® 49)

4353021812.52.41.44
Carbon HS* T30051228433.418.561.51.8
Carbon HS TR30S64035633.418.561.91.8
Carbon HS T70071139533.418.562.11.8
Polyester3752681712.143.51.4

* Carbon fibres are grouped according to the modulus band in which they fall. These bands are commonly referred to as: high strength (HS), intermediate modulus (IM), high modulus (HM) and ultra high modulus (UHM).

 

Notes:

These calculations were done to establish comparisons among the fibers alone and not as they interact with resin. These values are tensile properties. (compression or shear performance would show a totally different classification)