Polímeros - Brasil Escola

Summary

In this educational chemistry video, the instructor introduces the concept of polymers, explaining them as large molecules formed by the joining of smaller ones. Polymers can be natural or synthetic and come in various types, including addition, condensation, and rearrangement polymers. The video highlights everyday examples like polyethylene, PVC, nylon, and Kevlar, alongside distinctions between thermoplastic and thermoset polymers. The lesson is aimed at providing a fundamental understanding of polymerization processes and material types, with a focus on their relevance in daily life and industrial applications.

Takeaways

• 😀 Polymers are large molecules formed by linking smaller molecules (monomers) together, like a chain of links.
• 😀 The word 'polymer' comes from the Greek words 'poly' (many) and 'meros' (parts), meaning many parts united to form one.
• 😀 Polymers can be either natural (like cotton and silk) or artificial (like polyethylene used in plastics).
• 😀 Addition polymers are formed by adding monomers together without eliminating any by-products, such as polyethylene, PVC, and polypropylene.
• 😀 Condensation or elimination polymers are formed by condensing monomers, releasing a by-product like water. Examples include nylon, PET, and Kevlar.
• 😀 Rearrangement polymers are formed when monomers rearrange during polymerization. Polyurethane, used in foam products, is an example.
• 😀 Polyethylene, PVC, and polypropylene are common examples of addition polymers used in everyday items like bags, pipes, and containers.
• 😀 Nylon, PET, and Kevlar are examples of condensation polymers, used in products like clothing, plastic bottles, and bulletproof vests.
• 😀 Polyurethane is an example of a rearrangement polymer, often used in foam products and protective materials.
• 😀 Thermoplastic polymers can be reshaped when heated, like plastic bags, while thermosetting polymers, such as those in phone casings, become rigid and cannot be reshaped.
• 😀 Polymers play a crucial role in both natural systems (like animal horns and silk) and synthetic materials (like plastics and foam).

Q & A

What are polymers?

Polymers are macromolecules formed by linking many small molecules, known as monomers, together to create a long chain. These chains can vary in size and structure depending on the type of polymer.

What is the meaning of the word 'polymer'?

The word 'polymer' comes from two Greek words: 'poly' meaning many, and 'mer' meaning part. It refers to a substance made up of many repeating smaller units, called monomers.

Can polymers be both natural and artificial?

Yes, polymers can be both natural and artificial. Natural polymers include materials like cotton, silk, and even animal horns and shells, while artificial polymers are synthesized in laboratories, such as polyethylene and PVC.

What are addition polymers, and how are they formed?

Addition polymers are formed by linking monomers together without eliminating any atoms. A common example is polyethylene, where ethylene monomers are added together to form the polymer.

What is the difference between condensation and addition polymers?

Condensation polymers are formed by the joining of monomers with the elimination of small molecules, such as water. In contrast, addition polymers are formed by directly adding monomers together without any elimination of atoms.

What are some examples of condensation polymers?

Examples of condensation polymers include nylon (used in textiles), polyester (PET, used in plastic bottles), and Kevlar (used in protective gear). These polymers are created by eliminating small molecules, typically water, during the reaction.

What is a polymer of rearrangement?

A polymer of rearrangement occurs when monomers react and undergo structural changes as they link together. An example of this type of polymer is polyurethane, which is used in foams and elastomers.

How do thermoplastics differ from thermosetting polymers?

Thermoplastics can be repeatedly melted and reshaped without changing their chemical structure, while thermosetting polymers form a rigid structure once set and cannot be reshaped after curing.

Can thermoplastic polymers be reshaped?

Yes, thermoplastic polymers can be melted and re-molded into different shapes without changing their chemical composition. Examples include plastics used for grocery bags.

What are some everyday examples of addition, condensation, and rearrangement polymers?

Common examples include: Addition polymers - polyethylene (plastic items), PVC (pipes), polypropylene; Condensation polymers - nylon (clothing), PET (plastic bottles), Kevlar (protective gear); Rearrangement polymers - polyurethane (foam products).