chemistry

Polymer matrix composite

Polymer matrix composite is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Polymer matrix composite rather than just read about it. In short: In materials science, a polymer matrix composite (PMC) is a composite material composed of a variety of short or continuous fibers bound together by a matrix of organic polymers. PMCs are designed to transfer loads between fibers of a matrix.

Key takeaways

Polymer matrix composite belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Polymer matrix composite to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Polymer matrix composite from memory before moving on to harder problems.

Reference excerpt

In materials science, a polymer matrix composite (PMC) is a composite material composed of a variety of short or continuous fibers bound together by a matrix of organic polymers. PMCs are designed to transfer loads between fibers of a matrix. Some of the advantages with PMCs include their light weight, high resistance to abrasion and corrosion, and high stiffness and strength along the direction of their reinforcements.

Matrix materials The function of the matrix in PMCs is to bond the fibers together and transfer loads between them. PMCs matrices are typically either thermosets or thermoplastics. Thermosets are by far the predominant type in use today. Thermosets are subdivided into several resin systems including epoxies, phenolics, polyurethanes, and polyimides. Of these, epoxy systems currently dominate the advanced composite industry.

Thermosets Thermoset resins require addition of a curing agent or hardener and impregnation onto a reinforcing material, followed by a curing step to produce a cured or finished part. Once cured, the part cannot be changed or reformed, except for finishing. Some of the more common thermosets include epoxy, polyurethanes, phenolic and amino resins, bismaleimides (BMI, polyimides), polyamides. Of these, epoxies are the most commonly used in the industry. Epoxy resins have been in use in U.S. industry for over 40 years. Epoxy compounds are also referred to as glycidyl compounds. The epoxy molecule can also be expanded or cross-linked with other molecules to form a wide variety of resin products, each with distinct performance characteristics. These resins range from low-viscosity liquids to high-molecular weight solids. Typically they are high-viscosity liquids. The second of the essential ingredients of an advanced composite system is the curing agent or hardener. These compounds are very important because they control the reaction rate and determine the performance characteristics of the finished part. Since these compounds act as catalysts for the reaction, they must contain active sites on their molecules. Some of the most commonly used curing agents in the advanced composite industry are the aromatic amines. Two of the most common are methylene-dianiline (MDA) and sulfonyldianiline (DDS). SiC–SiC matrix composites are a high-temperature ceramic matrix processed from preceramic polymers (polymeric SiC precursors) to infiltrate a fibrous preform to create a SiC matrix. Several other types of curing agents are also used in the advanced composite industry. These include aliphatic and cycloaliphatic amines, polyaminoamides, amides, and anhydrides. Again, the choice of curing agent depends on the cure and performance characteristics desired for the finished part. Polyurethanes are another group of resins used in advanced composite processes. These compounds are formed by reacting the polyol component with an isocyanate compound, typically toluene diisocyanate (TDI); methylene diisocyanate (MDI) and hexamethylene diisocyanate (HDI) are also widely used. Phenolic and amino resins are another group of PMC resins. The bismaleimides and polyamides are relative newcomers to the advanced composite industry and have not been studied to the extent of the other resins.

Thermoplastics Thermoplastics currently represent a relatively small part of the PMC industry. They are typically supplied as nonreactive solids (no chemical reaction occurs during processing) and require only heat and pressure to form the finished part. Unlike the thermosets, the thermoplastics can usually be reheated and reformed into another shape, if desired.

Dispersed materials

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Polymer matrix composite

Start with the simplest possible case. Write down what Polymer matrix composite claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Polymer matrix composite before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Polymer matrix composite ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Polymer matrix composite

In research: Polymer matrix composite appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Polymer matrix composite in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Polymer matrix composite is common in secondary-school and first-year university syllabi. It links to neighbouring topics Composite materials, Fibre-reinforced polymers, so understanding it makes those chapters shorter.
In everyday life: Look for Polymer matrix composite outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Polymer matrix composite in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Polymer matrix composite means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Polymer matrix composite out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Polymer matrix composite in simple terms?

Why does Polymer matrix composite matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Polymer matrix composite?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Polymer matrix composite.