Name: polymer structures and uses
Uploaded: 2020-11-23T11:47:33.000Z
Duration: 2 min 34 s
Channel: JoVE

A polymer is a chain of small molecules, called monomers, that are held together by covalent bonds. Organisms can synthesize biological polymers, or scientists can synthesize polymers in the laboratory.
Natural polymers include DNA, the genetic material found in all living organisms, and proteins, polysaccharides, and lipids, the building blocks of life.
Plastics are some of the most common synthetic polymers and include nylon, polyethylene, and teflon.
The process of monomers linking to each other to form a larger molecule is known as polymerization. Monomers polymerize by two distinct reaction mechanisms, condensation and addition.
Condensation polymerization is when two monomers with a reactive hydrogen atom and hydroxyl group, respectively, link to each other, with the release of water as a by-product. Most natural polymers are formed through condensation reactions.
In addition polymerization, monomers with carbon-carbon double bonds are added to each other to form a polymer without the generation of any by-product through the release of atoms. &#160;&#160;&#160;&#160;&#160;&#160;
Polymers that are made up of the same type of monomers are known as homopolymers, and those made up of different types of monomers are known as heteropolymers. Cellulose, the most abundant natural polymer, is a homopolymer of glucose, whereas agarose, a polymer of marine origin, is a heteropolymer of galactose and 3,6-anhydro-L-galactopyranose.
Polymers have various structures depending on their type of monomers. Linear polymers are long chains of monomers. For example, cellulose is a linear polymer held together by beta 1,4-glycosidic bonds.&#160;
Branched polymers have chains splitting off of the main chain, such as amylopectin, a component of starch that branches out after 24 to 30 monomers through alpha 1,6-glycosidic bonds.
Crosslinked polymers have two or more chains held together at several points like a ladder, such as a synthetically constructed silicon ladder polymer, or form a complex network of interlinked chains&#8212;like the gel formed by pectins in jellies and jams.

polymers

Polymers

The word polymer is derived from the Greek words &#8220;poly&#8221; which means &#8220;many&#8221; and &#8220;mer&#8221; which means &#8220;parts&#8221;. Polymers are long chains of molecules composed of repeating units of smaller molecules, known as monomers. They either occur naturally, such as DNA and proteins, or can be constructed synthetically, like plastics. They have varied structural characteristics, such as linear chains, branched chains, or complex networks, that contribute to the properties that they exhibit. Additionally, functional groups that may be present on a polymer further define their properties. The individual units of a polymer are held together by stable covalent bonds that occur through either addition or condensation polymerization.
Addition Polymerization
Additional polymerization occurs when the monomers that participate in the reaction have double bonds. This reaction requires the presence of an external molecule that has an unpaired valence electron to initiate the reaction. This unpaired electron is highly reactive and forms a bond with one of the double bonds in a monomer, which leads to the monomer having an unpaired valence electron. This unpaired valence electron then associates with another monomer with double bonds leading to a chain reaction where the molecule keeps adding other monomers with double bonds to it. This results in the formation of a chain of monomers, with the one added most recently having an unpaired valence electron. This addition reaction continues until two chains with unpaired electrons react with each other to form a bond. This eliminates any unpaired valence electrons, resulting in the termination of the reaction.
Condensation Polymerization
Condensation polymerization, also known as step-growth polymerization, requires a catalyst, such as an acid or an enzyme, and the monomers must have at least two reactive functional groups, such as amines or carboxylic acids. Functional groups on monomers react with each other to form linkages such as ester or amide linkages and are accompanied by the loss of a small molecule, such as water. Condensation polymerization is a slower reaction compared to addition polymerization and, in many cases, requires the presence of heat.
This text is adapted from <a href="https://openstax.org/books/chemistry-2e/pages/Hydrocarbons">Openstax, Chemistry 2e, Chapter 20.1: Hydrocarbons</a>.

The word polymer is derived from the Greek words &#8220;poly&#8221; which means &#8220;many&#8221; and &#8220;mer&#8221; which means &#8220;parts&#8221;. ...

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Molecular Biology

Unit 1

Biochemistry of the Cell

KEY TERMS AND CONCEPTS

polymer structures and uses

Polymers are large molecules built from repeating smaller units called monomers. Their long-chain structure gives them many different properties and makes them useful in everyday materials.

Polymers can form in two main ways. In addition polymerization, monomers join together without losing any atoms. In condensation polymerization, monomers link while a small molecule is released. These two pathways help explain how many common plastics and related materials are made.

The structure of a polymer affects how it behaves. Some polymers are flexible, while others are more rigid. Some are used in packaging, clothing, and medical materials. Understanding polymer structure helps explain why these materials can have such different uses.

Polymer Structures and Uses

the periodic table and organismal elements

the-periodic-table-and-organismal-elements

Element Groups in Living Things

Living things are built from elements found on the periodic table. This page focuses on the elements that make up organisms and how they are grouped in biology. These organismal elements are usually divided into major, minor, and trace categories. Major elements make up most of the mass of living matter. Minor elements are needed in smaller amounts. Trace elements are present in very small amounts but still play important roles. The periodic table helps show where these elements fit and how...

functional groups

Functional Groups in Organic Molecules

Functional groups are the parts of organic molecules that give them specific chemical behavior. They help determine how a compound reacts and what properties it has. In organic chemistry, these groups are used to classify molecules in a clear way. Hydrocarbons are one common class of organic compounds. They contain only carbon and hydrogen. Alcohols, aldehydes, and ketones are other classes that are identified by their functional groups. These groups make each class behave differently from the...

Polymers are large molecules built from repeating smaller units called monomers. Their long-chain structure gives them many different properties and makes them useful in everyday materials. Polymers can form in two main ways. In addition polymerization, monomers join together without losing any atoms. In condensation polymerization, monomers link while a small molecule is released. These two pathways help explain how many common plastics and related materials are made. The structure of a...

what are lipids?

Lipids in Cells: Fats and Membranes

Lipids are a group of biomolecules found in living things. They are known for their role in energy storage and in building cell membranes. This makes them important in many parts of biology. Fats are one common type of lipid. Other lipids include phospholipids and steroids. Each group has a different structure and a different job in the body. Phospholipids are especially important because they help form cell membranes. Steroids also belong to the lipid group, and they have their own distinct...

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intermolecular forces

Forces Between Molecules

Forces between molecules help explain why matter behaves the way it does. These intermolecular attractions act between separate molecules, not within a single molecule. They are often much weaker than the bonds that hold atoms together inside a molecule, but they still affect many properties of liquids and solids. Several common types of intermolecular forces are covered in this topic. These include dipole-dipole forces, hydrogen bonding, ion-dipole forces, and van der Waals forces. Van der...

noncovalent attractions in biomolecules

How Biomolecules Hold Their Shape

Biomolecules hold their shape through noncovalent attractions. These interactions occur within and between molecules and help control the structure and stability of complexes. They are different from covalent bonds because they do not involve sharing electrons. Four main noncovalent interactions are important in biology: hydrogen bonds, van der Waals forces, ionic bonds, and hydrophobic interactions. Hydrogen bonds form when a hydrogen atom is covalently bonded to a strongly electronegative...

pH Scale and Acid-Base Balance

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ATP Hydrolysis and Energy Release

ATP hydrolysis is a key chemical reaction in cells that releases energy. ATP, or adenosine triphosphate, is the molecule cells use to store and transfer energy for many processes. During hydrolysis, water breaks the bond in ATP’s terminal phosphate group. This reaction converts ATP into ADP, or adenosine diphosphate, and inorganic phosphate. The released energy can then be used to drive cellular work. High school biology students often see ATP hydrolysis as part of energy transfer in living...

key terms and concepts

Learn how polymers are built from monomers, how addition and condensation polymerization work, and why polymer structure affects everyday materials.

Polymer Structures and Uses | JoVE K12

molecular biology

JoVE Core Molecular Biology showcases the molecular processes of the cell through clear and concise animated video lessons. Additionally, in scientist-in-action videos, these concepts' application is demonstrated through real experiments in modern laboratories.

Polymer Structures and Uses

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