13.4Q) Elastomers

Covalent bonding is chemical bonding from...?

• ...the attraction of positive metal ions and delocalized electrons.

• ...sharing of electron pairs between atoms.

• ...the transfer of electrons between atoms.

• ...the attraction between electronegative atoms and lone pairs.

Tags

NGSS.HS-PS1-1

Covalent bonding gets stronger if...

• ...there are more delocalized electrons.

• ...there are more shared electrons.

• ...the size of the atoms get bigger.

• ...the mass of the atoms get bigger.

Covalent bonds require...

• ...high energy to break.

• ...moderate energy to break.

• ...low energy to break.

Tags

NGSS.HS-PS1-4

Van der Waals forces for small molecules require...

• ...high energy to break.

• ...moderate energy to break.

• ...low energy to break.

Van der Waals forces for very large molecules require...

• ...high energy to break.

• ...moderate energy to break.

• ...low energy to break.

Which mechanical properties have high values in most elastomers?

• Viscoelasticity

• Malleability

• Density gradient

• Grain Structure

• Tear resistance

Tags

NGSS.HS-PS2-6

Match the words to the categories

Groups:

(a) Macroscopic

,

(b) Microscopic

,

(c) Atomic/Molecular

,

(d) Subatomic

• Morphology

• Non-metal elements

• Amorphous regions

• Entropy

• Crystallinity

• Reptation

• Covalent Bonds

• Cross-linking

• Viscoelasticity

• Interchain interaction

• Hybridization

• Polymer chains

Match the following

• Polymer chains

• The chemical bonds that connect the polymer chains in elastomers, providing stability and memory of the relaxed state

• Cross-linking

• The mixing of atomic orbitals in carbon atoms, resulting in different bonding configurations (sp, sp2, sp3) that influence the properties of carbon-based materials

• Entropy

• The measure of the disorder or randomness in the polymer chain arrangement, which drives the elastomer to return to its relaxed, amorphous state when stress is removed

• Hybridization

• The long, intertwined molecular chains that make up the structure of elastomers, which can align and deform under stress

Tags

NGSS.HS-PS2-6

Match the following

• Reptation

• The disordered, irregular structure of the polymer chains in elastomers, which enables the material to exhibit high extensibility and flexibility

• Morphology

• The process by which individual polymer chains move within a virtual tube formed by the entanglement of neighboring chains, which can explain the viscoelastic behavior of elastomers

• Viscoelasticity

• 
  Arrangement and ordering of polymer chains.

• Crystallinity

• The complex, time-dependent elastic response of elastomers, which exhibits hysteresis in the stress-strain curve when the load is removed

• Amorphous regions

• The ordered, three-dimensional arrangement of polymer chains in semi-crystalline elastomers, which can coexist with amorphous regions and impact the mechanical, thermal, and other properties