Modacrylic

Key takeaways

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

Reference excerpt

A modacrylic is a synthetic copolymer. Modacrylics are soft, strong, resilient and dimensionally stable. They can be easily dyed, show good press and shape retention, and are quick to dry. They have outstanding resistance to chemicals and solvents, are not attacked by moths or mildew, and are nonallergenic. Among their uses are in apparel linings, furlike outerwear, paint-roller covers, scatter rugs, carpets, and work clothing and as hair in wigs. Commercial production of modacrylic fiber began in 1949 by Union Carbide Corporation in the United States. Modacrylic and acrylic fibers are similar in composition and at one time were in the same category. In 1960 the Federal Trade Commission decided to separate the two fibers and establish a category for each. The Federal Trade Commission defines modacrylic fibers as manufactured fibers in which the fiber-forming substance is any long-chain synthetic polymer composed of less than 85%, but at least 35% weight acrylonitrile units except when the polymer qualifies as rubber.

Production Modacrylic fibers are modified acrylic fibers made from acrylonitriles, but larger amounts of other polymers are added to make the copolymers. The modacrylic fibers are produced by polymerizing the components, dissolving the copolymer in acetone, pumping the solution into the column of warm air (dry-spun), and stretching while hot. Modacrylics are creamy or white and are produced in tow and staple form. If looked at in cross section views they have an irregular shape. Modacrylic fibers are also produced in many different lengths, crimp levels, deniers and they can have various shrinkage potentials. Current modacrylic fiber producers include Kaneka Corporation in Japan.

Properties A modacrylic has properties that are similar to an acrylic. However, modacrylics are flame retardant and do not combust. The fibers are difficult to ignite and will self-extinguish. In addition to a modacrylic's flame retardant properties it has a relatively high durability that is comparable to wool. Modacrylic fibers have a moderate resistance to abrasion and a very low tenacity. One of the most interesting properties of Modacrylic fabrics is the arc flash protection, where it has very good values. Modacrylics are poor conductors of heat. The fabrics are soft, warm and resilient but are prone to pilling and matting. Modacrylics display high performance when it comes to appearance retention. The fibers are quite resilient and will not wrinkle. They also have great dimensional stability and high elastic recovery, which gives them the ability to hold their shape.

Care Modacrylics are sensitive to loss of appearance due to improper care; therefore, it is important to know how to care for modacrylics. Modacrylics are resistant to acids, weak alkalis, and organic solvents. These fibers are also resistant to moths, mildew and sunlight. Modacrylic fabrics can be machine washed using warm water and tumble dried on a low setting. Modacrylic pieces can also be dry-cleaned, however, they should not be steamed and should only be tumbled on cold. Some fabrics may also be cleaned using the furrier method (a special non immersion cleaning process). The fibers are heat sensitive and will shrink at 121 °C (250 °F) and will stiffen at temperatures over 149 °C (300 °F).

Uses Modacrylics are used by producers of technically advanced fabrics for comfortable and protective blends often used in personal protective equipment, primarily when environmental resistance or flame retardancy is necessary or required. Modacrylics can combine flame retardancy with a relatively low density, keeping protective gear from being uncomfortably heavy (i.e. shirts and trousers worn by electrical linemen). The combination of flame retardancy and low density is also useful in furnishings, draperies, and outdoor fabrics. Modacrylics are also commonly used in fake fur fabrics, toupées, wigs and fleece-type fabric. By mixing the various forms of fibers one can easily create a realistic synthetic fur. The fabrics can then be sheared or embossed to resemble fur even more closely. The heat-sensitivity of modacrylic also allows wigs and hairpieces to be curled and heat styled without damage. Modacrylics are also used in fleece, knit-pile fabric backings, and nonwoven fabrics. Other uses of modacrylics include paint rollers, industrial fabrics, stuffed toys and filters.

References

Worked examples

Example 1 — a first encounter with Modacrylic

Start with the simplest possible case. Write down what Modacrylic claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Modacrylic 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 Modacrylic 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 Modacrylic

In research: Modacrylic appears in science 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 Modacrylic 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: Modacrylic is common in secondary-school and first-year university syllabi. It links to neighbouring topics Plastics, Synthetic fibers, so understanding it makes those chapters shorter.
In everyday life: Look for Modacrylic 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.

How to study Modacrylic in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Modacrylic 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 Modacrylic out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Modacrylic in simple terms?

A modacrylic is a synthetic copolymer. Modacrylics are soft, strong, resilient and dimensionally stable.

Why does Modacrylic matter?

Because it connects several science 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 Modacrylic?

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 Modacrylic.