18 Questions
What is the primary reason for the reduction in density of a polymer?
Presence of substituents or branches in the polymer chains
What is the main characteristic of thermoplastic polymers?
They have both ordered crystalline regions and amorphous noncrystalline regions
What is the primary function of cross-linking in thermosetting polymers?
To provide rigidity to the polymer by forming covalent bonds
What is the characteristic of elastomers that allows them to return to their original state when the stretching force is released?
Presence of cross-linking between polymer chains
How do the crystalline regions in a polymer affect its physical properties?
They make the polymer more dense, harder, and more resistant to heat
What is the primary difference between thermoplastic and thermosetting polymers?
Thermoplastic polymers can be remelted, while thermosetting polymers cannot
What type of polymerization is associated with the chain-growth process?
Addition polymerization
What is the characteristic feature of a branched polymer?
It has short branches connected to the main chain
What type of forces hold individual polymer chains together?
Van der Waals forces
What is the term for regions of a polymer where chains are highly ordered with respect to one another?
Crystallites
What is the characteristic feature of the step-growth process?
Chains have at least two growth points
What type of polymerization is associated with the step-growth process?
Condensation polymerization
What is the primary method used to prepare addition polymers?
Linking monomers through an addition reaction.
What do the brackets in a polymer formula represent?
The repeating unit of the polymer.
What is a characteristic feature of condensation polymers?
They are formed by removing a small molecule, such as water or an alcohol.
What is the term for the process of linking monomers to form a polymer?
Polymerization.
What is the primary focus of materials science, as it relates to polymers?
Creating new materials with improved properties.
What is the term for polymers synthesized by cells?
Biopolymers.
Learn about the structure of polymers, including crystalline and amorphous regions, and how it affects their properties such as density, hardness, and heat resistance. Understand how polymer chains are classified based on their properties.
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