Questions and Answers
What type of polymerization involves the linear growth of molecules and the shifting of free radicals?
Which factor is NOT typically associated with polymerization reactions?
What is the primary characteristic of the ring opening mechanism in polymerization?
Which method of termination in radical polymerization involves the direct coupling of two radicals?
Signup and view all the answers
What type of material is an example of a polymer formed via ring-opening polymerization?
Signup and view all the answers
What key aspect is affected by the thermal behavior of polymers during polymerization?
Signup and view all the answers
What major disadvantage is associated with residual monomer in polymerization processes?
Signup and view all the answers
During which stage of polymerization would shrinkage primarily occur?
Signup and view all the answers
What is the term for a polymer composed of a single type of monomer?
Signup and view all the answers
Which of the following best describes an oligomer?
Signup and view all the answers
In terms of spatial configuration, what does a branched polymer refer to?
Signup and view all the answers
What type of polymer consists of more than one type of monomer?
Signup and view all the answers
Which of the following is a natural polymer?
Signup and view all the answers
What is the primary bond type in intermolecular forces within polymers?
Signup and view all the answers
Which of the following is not a characteristic of the polymerization reaction?
Signup and view all the answers
What is the result of a polymer that is classified based on its origin?
Signup and view all the answers
Which characteristic is true for thermoplasts?
Signup and view all the answers
What differentiates addition polymerization from condensation polymerization?
Signup and view all the answers
Which type of polymerization is typically slower and produces shorter polymer chains?
Signup and view all the answers
Which of the following polymers is associated with condensation polymerization in clinical applications?
Signup and view all the answers
What is the main reason condensation polymerization results in small molecular weight products?
Signup and view all the answers
Which statement is true regarding thermosets?
Signup and view all the answers
What initiates the activation and initiation in addition polymerization?
Signup and view all the answers
Which of the following properties is NOT typically associated with thermoplasts?
Signup and view all the answers
Study Notes
Free Radical Polymerization
- Involves radical compounds with an unpaired electron, initiated using light or chemical means.
- Initiation requires a radical generator like benzoyl peroxide to form free radicals.
Propagation
- Characterized by linear growth of molecules through the addition of free radicals to the end of the growing chain.
Termination Mechanisms
- Direct Coupling: Two free radicals combine to terminate the reaction.
- Hydrogen Atom Transfer: Involves the transfer of hydrogen atoms between radicals, leading to new bond formation.
Factors Influencing Polymerization
- Heat generation occurs during polymerization.
- Shrinkage and the presence of residual monomer can affect the final product.
Ring Opening Mechanism
- Utilizes terminal reactive groups within cyclic monomers.
- Examples: Polyether rubber impression material and low shrinkage composites (Siloranes).
Types of Polymers
- Thermoplasts: Physical reactions, soft, can be remelted and reformed. Sensitive to heat. Example: Acrylic resin.
- Thermosets: Chemical reactions, cannot be remelted, degrades upon heating, high mechanical properties.
Polymer Preparation Reactions
-
Condensation Polymerization:
- Involves stepwise reactions with multiple monomer species.
- Produces low molecular weight due to by-product elimination.
- Slower with shorter polymer chains. Relevant in polysulfide rubber impression materials.
-
Addition Polymerization:
- Faster reaction without by-products.
- Results in high molecular weight polymers.
Polymer Structure
- Polymers are long-chain organic molecules made of repeated units called monomers.
- Monomer: Smallest repeating unit (single).
- Oligomer: Short polymer composed of 10 monomers.
Bonding Types in Polymers
- Intramolecular bonds (primary bonds) are covalent.
- Intermolecular bonds (secondary bonds) connect individual polymer chains.
Polymerization Reaction
- Process by which monomer units chemically link to form high molecular weight polymers.
- Homopolymers: Comprised of one type of monomer.
- Copolymer: Made from more than one type of monomer.
Classification of Polymers
-
By origin:
- Natural: Proteins, polysaccharides, DNA, RNA.
- Synthetic: Bakelite, nylon, PMMA, polyvinyl chloride.
-
By spatial configuration:
- Linear, branched, and cross-linked structures.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the fascinating world of chemical reactions involving free radicals and initiators. This quiz will test your understanding of how these chemical groups with unpaired electrons interact under the influence of light and other factors. Get ready to dive into the complexities of radical compounds!
