Vinyl Monomers

Definition

Vinyl monomers are unsaturated organic compounds containing a vinyl group, which is a carbon-carbon double bond attached to two hydrogen atoms. These monomers are the building blocks for the formation of chain-growth polymers through radical addition reactions.

5 Must Know Facts For Your Next Test

1. Vinyl monomers can undergo radical addition reactions to form long polymer chains, a process known as chain-growth polymerization.
2. The presence of the carbon-carbon double bond in vinyl monomers allows for the initiation of radical polymerization through the addition of free radical species.
3. Vinyl monomers commonly used in chain-growth polymerization include ethylene, propylene, styrene, and vinyl chloride.
4. The propagation step in radical polymerization of vinyl monomers involves the successive addition of monomers to the growing polymer chain.
5. Chain-growth polymers formed from vinyl monomers typically have a high degree of polymerization, resulting in long, linear macromolecules.

Review Questions

• Explain the role of the carbon-carbon double bond in vinyl monomers during radical polymerization.
  • The carbon-carbon double bond in vinyl monomers is essential for the initiation of radical polymerization. The presence of this reactive double bond allows for the addition of free radical species, which can then propagate the polymer chain growth through the successive addition of more vinyl monomers. The double bond provides the necessary site for the radical reaction to occur, enabling the formation of long, chain-growth polymers.
• Describe the key steps involved in the radical polymerization of vinyl monomers to form chain-growth polymers.
  • The radical polymerization of vinyl monomers to form chain-growth polymers typically involves three main steps: initiation, propagation, and termination. In the initiation step, a free radical species reacts with the carbon-carbon double bond of a vinyl monomer, creating a new radical-containing species. During the propagation step, this radical-containing species then adds successive vinyl monomers to the growing polymer chain. The termination step occurs when two radical-containing species combine, or when a radical species reacts with a non-radical species, resulting in the cessation of the chain-growth polymerization process.
• Analyze the relationship between the structure of vinyl monomers and the properties of the resulting chain-growth polymers.
  • The structure of vinyl monomers, particularly the presence of the carbon-carbon double bond, directly influences the properties of the chain-growth polymers formed. The unsaturated nature of the vinyl group allows for the initiation and propagation of radical polymerization, leading to the formation of long, linear macromolecules. The specific substituents attached to the vinyl group, such as the type and number of carbon atoms, can also affect the physical and chemical properties of the resulting polymers, including their thermal stability, mechanical strength, and chemical resistance. Understanding the relationship between vinyl monomer structure and polymer properties is crucial for designing and engineering materials with desired characteristics for various applications.

Related terms

Radical Polymerization: A type of chain-growth polymerization mechanism where free radical intermediates propagate the polymer chain growth.

Chain-Growth Polymers: Polymers formed by the successive addition of monomers to a growing polymer chain, resulting in a high degree of polymerization.

Ethylene: The simplest vinyl monomer, consisting of two carbon atoms connected by a double bond and four hydrogen atoms.