/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 56 Give two examples of everyday it... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 10: Problem 56

Give two examples of everyday items that are thermosetting plastics. What are the properties of thermosetting plastics when heated and cooled?

Short Answer

Expert verified
Examples: melamine plates and Bakelite insulators. Properties: rigid, heat-resistant, do not melt when reheated.

Step by step solution

01

Understanding Thermosetting Plastics

Thermosetting plastics are polymers that irreversibly cure, typically through a chemical reaction induced by heat. Once set, they don't melt or reshape on reheating, unlike thermoplastics.
02

Example 1 - Dishware Plate

One common everyday item made from thermosetting plastic is a melamine dishware plate. Melamine, a type of thermosetting plastic, is used to make lightweight, durable, and heat-resistant plates.
03

Example 2 - Electrical Insulator

Bakelite, another thermosetting plastic, is often used for electrical insulators. It is used in electrical appliances due to its good insulating properties and heat resistance.
04

Properties When Heated

Thermosetting plastics remain firm and solid when heated; instead of melting, they may char or burn if heated significantly beyond their temperature limits.
05

Properties When Cooled

Once thermosetting plastics have cured, cooling won't alter their shape or return them to a malleable state. They maintain their strength and structure.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Melamine
Melamine is a well-known example of a thermosetting plastic. It is widely recognized for its application in creating dishware, like plates and bowls. The reason melamine is preferred for this purpose lies in its unique properties:
  • **Durability**: Melamine is tough and can withstand drops and impact, making it suitable for daily use.
  • **Heat Resistance**: It can resist a fair amount of heat without deforming, which is perfect for serving hot food.
  • **Lightweight**: Unlike ceramic or glass, melamine is light, making it easy to handle and store.
  • **Stain Resistance**: Melamine is less likely to absorb stains, keeping dishware looking clean and fresh.
Melamine鈥檚 thermosetting nature means that after it鈥檚 set, it remains in its solid form. It won鈥檛 reset or melt with heat, offering consistency and longevity to the products made from it.
Bakelite
Bakelite is an early form of thermosetting plastic, discovered in 1907 by Leo Baekeland. It's聽famous for its use as an electrical insulator. Here's why Bakelite is highly valued for this purpose:
  • **High Electrical Insulation**: Bakelite doesn't conduct electricity, making it ideal for electrical appliances and components like switches and sockets.
  • **Thermally Stable**: It can withstand high levels of heat without melting, making it safe for use in electrical applications.
  • **Chemical Resistance**: Bakelite is resistant to many chemicals and solvents, adding to its durability.
Moreover, Bakelite's thermosetting properties prevent it from changing shape once it's molded. This technology paved the way for a wide array of electrical applications and other uses, making Bakelite revolutionary in its time.
Chemical Reaction
The defining feature of thermosetting plastics is the chemical reaction they undergo during their curing process. Unlike thermoplastics, which melt and reshape upon heating, thermosetting plastics like melamine and Bakelite are irreversibly set through a specific chemical mechanism:
  • **Cross-linking**: During curing, bonds form between the polymer chains. This process is known as cross-linking, and it creates a rigid three-dimensional structure.
  • **Heat Activation**: Typically, heat triggers the chemical reaction that results in curing. Once cured, the structure becomes rigid and permanent.
  • **Irreversible Process**: After the reaction, the material's new form is stable and does not change with further heating. Unlike thermoplastics, they won't melt back into a liquid state.
Understanding these chemical reactions emphasizes why thermosetting plastics are chosen for applications requiring robust mechanical and thermal properties, as they won't easily deform or degrade when exposed to heat.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Silicones are Si-containing polymers used in waterproof caulking. They do not contain carbon-to-carbon bonds. (a) Silly Putty is a polymer made from the monomer dimethylsilanol, \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{Si}(\mathrm{OH})_{2}\). Write the structure of four units of this polymer. (b) Identify the type of polymerization that occurs.

Do polar compounds appear earlier or later on a chromatogram when a nonpolar stationary phase is used? Explain your answer.

Locate the grid for Question \(115 .\) Each of its nine lettered boxes contains an item that can be used to fill in the blanks that follow. Items may be used more than once and there may be more than one correct item for a blank. Place the letter(s) of the correct selection(s) on the appropriate line. (a) A triglyceride (b) Final oxidation product of a primary alcohol (c) Condensation polymerization monomer (d) Segment of an addition polymer molecule (e) Initial oxidation product of a primary alcohol (f) Contains an amide bond (g) Addition polymerization monomer

In his 1989 essay "The End of Nature," William McKibben states that "... a clean burning automobile engine will emit \(5.5 \mathrm{lb}\) of carbon in the form of carbon dioxide for every gallon of gasoline it consumes." Assume that the gasoline is \(\mathrm{C}_{8} \mathrm{H}_{18}\) and its density is \(0.703 \mathrm{~g} / \mathrm{mL}\) (a) Write a balanced equation for the complete combustion of gasoline. (b) Is McKibben's assertion correct? Support your answer with calculations.

Explain how the octane number of a gasoline is determined.
See all solutions

Recommended explanations on Chemistry Textbooks

The Earths Atmosphere

Read Explanation

Chemical Analysis

Read Explanation

Making Measurements

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Inorganic Chemistry

Read Explanation

Organic Chemistry

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.