Properties This article has property data, click to view

S-Glass Fibre

Topics Covered


Fibre Manufacture


Key Properties


Composite Materials


E-Glass has been used extensively in polymer matrix composites, commonly termed “fibreglass”. These materials exhibit good mechanical properties, however, these have not been sufficient in some instances. Consequently, the E-glass composition has been modified to produce more desirable properties. A higher stiffness material resulting from this is S-Glass.

Fibre Manufacture

Glass fibres are generally produced using melt spinning techniques. These involve melting the glass composition into a platinum crown which has small holes for the molten glass to flow. Continuous fibres can be drawn out through the holes and wound onto spindles, while short fibres may be produced by spinning the crown, which forces molten glass out through the holes centrifugally. Fibres are cut to length using mechanical means or air jets.

Fibre dimension and to some extent properties can be controlled by the process variables such as melt temperature (hence viscosity) and drawing/spinning rate. It should be noted that S-glass is more difficult to process compared to E-glass.

As fibres are being produced, they are normally treated with sizing and coupling agents. These reduce the effects of fibre-fibre abrasion which can significantly degrade the mechanical strength of the individual fibres. Other treatments may also be used to promote wetting and adherence of the matrix material to the fibre.


S-Glass has a typical nominal composition of SiO2 65wt%, Al2O3 25wt%, MgO 10wt%. Some other materials may also be present at impurity levels.

Key Properties

Properties that have made E-glass so popular in fibreglass and other glass fibre reinforced composite include:

         High production rates

         Improved mechanical properties compared to E-glass

         High strength, (see table 1)

         High stiffness

         Relatively low density


         Resistant to heat

         Good chemical resistance

         Relatively insensitive to moisture

         Able to maintain strength properties over a wide range of conditions

Table 1. Comparison of typical properties for some common fibres.


Density (g/cm3)

Tensile Strength (MPa)

Young modulus (GPa)









Alumina (Saffil)








Kevlar 29




Kevlar 49




The advantageous properties of S-glass generally outweigh the disadvantages which include:

         Significantly higher cost compared to E-glass

         Self abrasiveness if not treated appropriately leading to reduced strength

         Relatively low fatigue resistance

         Higher density compared to carbon fibres and organic fibres.


Composite Materials

S-Glass is generally used for polymer matrix composites that require improved mechanical properties compared to E-glass based composites. This is often the case when the material is operated under more extreme conditions.


Primary author:


Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Your comment type
Azthena logo powered by Azthena AI

Your AI Assistant finding answers from trusted AZoM content

Azthena logo with the word Azthena

Your AI Powered Scientific Assistant

Hi, I'm Azthena, you can trust me to find commercial scientific answers from

A few things you need to know before we start. Please read and accept to continue.

  • Use of “Azthena” is subject to the terms and conditions of use as set out by OpenAI.
  • Content provided on any AZoNetwork sites are subject to the site Terms & Conditions and Privacy Policy.
  • Large Language Models can make mistakes. Consider checking important information.

Great. Ask your question.

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.