chemistry

Solution polymerization

Solution polymerization 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 Solution polymerization rather than just read about it. In short: Solution polymerization is a method of industrial polymerization. In this procedure, a monomer is dissolved in a non-reactive solvent that contains a catalyst or initiator.

Key takeaways

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

Reference excerpt

Solution polymerization is a method of industrial polymerization. In this procedure, a monomer is dissolved in a non-reactive solvent that contains a catalyst or initiator. The reaction results in a polymer which is also soluble in the chosen solvent. Heat released by the reaction is absorbed by the solvent, reducing the reaction rate. Moreover, the viscosity of the reaction mixture is reduced, preventing autoacceleration at high monomer concentrations. A decrease in viscosity of the reaction mixture by dilution also aids heat transfer, one of the major issues connected with polymer production, since most polymerizations are exothermic reactions. Once the desired conversion is reached, excess solvent must be removed to obtain the pure polymer. Accordingly, solution polymerization is primarily used in applications where the presence of a solvent is desired anyway, as is the case for varnish and adhesives. Another application of polymer solutions includes the manufacture of fibers by wet or dry spinning or plastic films. Disadvantages of solution polymerization are decrease of monomer and initiator concentration leading to reduction of reaction rate, lower volume utilization of reactor, additional cost of the process related to solvent recycling, toxicity and other environmental impacts of most of organic solvents. One of the major disadvantages of the solution polymerization technique is that however inert the selected solvent may be, chain transfer to the solvent cannot be completely ruled out and, hence, it is difficult to get very high molecular weight product. From common solvents, especially chlorinated hydrocarbons are susceptible to chain transfer in radical polymerization. Intensity of chain transfer for different compounds may be quantified by use of chain transfer constants and the decrease of degree of polymerization may be calculated using Mayo equation.

Industrially important polymers produced by solution polymerization

Sources: Polyacrylonitrile (PAN) is manufactured by radical polymerization in dimethylformamide (DMF), dimethyl sulfoxide (DMSO), organic carbonates, sulfuric acid, nitric acid or water solutions of inorganic salts and converted to fibers. Polyacrylic acid (PAA) and polyacrylamide are obtained by radical polymerization in water solution and used as thickeners, adhesives or flocculants. Acrylate and methacrylate homo- and copolymers are made by radical polymerization in toluene-acetone for coating applications. Polyethylene (HDPE, LLDPE) - some grades are made by coordination polymerization in high boiling hydrocarbone solvents (above PE solution temperature). The advantage of this process is very high propagation rate allowing fast changes of product grades. High cis polybutadiene (BR) is manufactured by coordination polymerization in hydrocarbons. Solution styrene-butadiene rubber (sSBR) is produced by anionic polymerization in hydrocarbons leading to rubber with better properties for making tires than emulsion polymerization type. Polyvinyl acetate used further for polyvinyl alcohol is manufactured by radical polymerization in methanol solution. Liquid polybutadienes are made by anionic or radical polymerization in hydrocarbon solutions. Butyl rubber (IIR) by low temperature cationic copolymerization of isobutylene with isoprene in ethylene or methylchloride solution. Aromatic polyamides (e.g. Kevlar and Nomex) are made by polycondensation in N-methyl-pyrrolidone and calcium chloride solution. This process is one of two used in the production of sodium polyacrylate, a superabsorbent polymer used in disposable diapers.

See also Dispersion polymerization Emulsion dispersion Superabsorbent polymer

References

Foundations of Materials Science and Engineering, fourth edition, William F. Smith & Javad Hashem Encyclopedia of Polymer Science and Technology, J.Wiley Sons, Interscience, Publ., New York, 4th edition, 1999-2012

Worked examples

Example 1 — a first encounter with Solution polymerization

Start with the simplest possible case. Write down what Solution polymerization 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 Solution polymerization 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 Solution polymerization 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 Solution polymerization

In research: Solution polymerization 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 Solution polymerization 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: Solution polymerization is common in secondary-school and first-year university syllabi. It links to neighbouring topics Polymerization reactions, so understanding it makes those chapters shorter.
In everyday life: Look for Solution polymerization 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 Solution polymerization in 20 minutes

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

Frequently asked questions

What is Solution polymerization in simple terms?

Solution polymerization is a method of industrial polymerization. In this procedure, a monomer is dissolved in a non-reactive solvent that contains a catalyst or initiator.

Why does Solution polymerization 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 Solution polymerization?

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 Solution polymerization.