key term - Elastomers

Definition

Elastomers are a class of polymers that exhibit elastic properties, allowing them to stretch and return to their original shape. This unique ability comes from their molecular structure, which consists of long chains that can deform under stress but recover when the stress is removed. Elastomers play a vital role in various applications due to their flexibility and resilience, especially in materials derived from phosphazenes and silicones.

5 Must Know Facts For Your Next Test

1. Elastomers are typically synthesized through processes such as addition polymerization or condensation polymerization, which influences their properties.
2. Silicone elastomers are known for their thermal stability and resistance to environmental factors like moisture and UV radiation.
3. Phosphazene elastomers can have tunable properties by varying the inorganic backbone, leading to applications in seals and gaskets.
4. The unique elastic properties of elastomers make them crucial in everyday items like tires, rubber bands, and medical devices.
5. Elastomers can be tailored for specific applications by adjusting their formulation, including the type of fillers and additives used.

Review Questions

• How do the molecular structures of elastomers contribute to their unique properties?
  • The molecular structure of elastomers consists of long, flexible polymer chains that can stretch under mechanical stress. This arrangement allows the material to deform significantly while maintaining the ability to return to its original shape once the stress is removed. The elasticity results from the interplay between the chain length and the degree of cross-linking within the material, which enhances both flexibility and resilience.
• Compare the characteristics of silicones and phosphazenes as elastomers and discuss their specific applications.
  • Silicones are known for their excellent thermal stability, moisture resistance, and flexibility, making them suitable for applications in medical devices, sealants, and electrical insulation. In contrast, phosphazenes offer tunable properties due to their inorganic backbone, leading to specialized uses in gaskets and seals where chemical resistance is critical. Both types of elastomers leverage their unique molecular structures to meet diverse application requirements.
• Evaluate the impact of cross-linking on the performance of elastomers derived from phosphazenes and silicones in industrial applications.
  • Cross-linking plays a crucial role in enhancing the performance of elastomers by improving their mechanical strength, thermal stability, and resistance to deformation. In phosphazene elastomers, cross-linking can tailor properties such as hardness and elasticity for specific industrial applications like seals or gaskets. For silicone elastomers, cross-linking provides a robust structure that retains flexibility while withstanding extreme temperatures and environmental conditions. Understanding how cross-linking influences these elastomeric materials is essential for optimizing their use in various industries.

Related terms

Polymer: Large molecules made up of repeating structural units (monomers), which can exhibit varied properties based on their composition and structure.

Cross-linking: A process where polymer chains are interconnected through covalent bonds, enhancing the mechanical properties and stability of elastomers.

Thermosetting Plastics: Polymers that undergo a permanent chemical change when heated, forming a rigid structure that cannot be remolded or reshaped.