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  • Writer's pictureNed Patton

It's Just String and Glue After All

What exactly are composite materials anyway?

Wikipedia says the following:

A composite is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a material with properties unlike the individual elements.”

So, what – exactly does that mean to someone who is trying to understand what all of the fuss is about? Well, that’s what I’m going to be talking about in this blog.

But first, let’s be more clear about what engineers and composites designers think a composite material is – especially the string and glue kind – fiber reinforced plastics.

Fiber reinforced plastics typically start with a fiber (glass, carbon, Kevlar, etc.) that is laid up in a particular pattern and in a particular way to provide the stiffness and strength for the material. Then this bed of fibers is infused with a liquid plastic (polyester, vinyl ester, epoxy) that will cure and become hard and strong. Then the liquid plastic or resin is cured so that the part becomes one solid piece.

This is the most common form of composites and the one that I will be talking about in this blog.

But first – let’s provide a few examples that everyone knows about and describe why they are composite materials. Some of these are the string and glue type of composite and some are more of what is called the “discontinuously reinforced composite”. The difference will become clear as I provide some examples

· Concrete – a mix of sand, gravel, and cement, where the sand and gravel are the reinforcement and the cement is the glue that binds all of it together. So, this is in the class of discontinuous composites.

· Plywood – a mix of layers of wood bound together with a glue where the orientation of the layers (plies) that make up the plywood are rotated 90 degrees to each other in every other layer. This is a classic string and glue composite that has continuous fibers (wood grain) in alternating orientation layers stuck together with glue

· Oriented Strand Board (OSB) – one of the most common building sheathing materials used today is a discontinuous composite where large flat wood chips are bound together with a glue and heat pressed to make a board.

· Fiberglass – the stuff your boat hull is made out of, or maybe even your bicycle frame, tennis racket, plastic shower stall or bathtub, the list goes on. Some of these are continuous fiber and some are chopped fiber, but they are all composites of glass fiber and a curable liquid plastic like polyester.

Well, that’s about enough for the first post. In future posts I’ll talk about the history of composites, how the Periodic Table of the Elements enables us to make these materials, all about strings, and all about glues. And then I can talk about the business of composites, who bought out who and all of the back room deals and patent disputes, what I see as new and upcoming things, and basically anything anyone is interested in reading about. So please if you have something you want to know, send me a message on LinkedIn and ask. I do really want to start a dialog with interested people about these wonderful materials that have so much possibility to make our lives better.


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