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Questions and Answers
Which of the following is classified as a natural polymer?
Which of the following is classified as a natural polymer?
What type of polymer is created through addition polymerization?
What type of polymer is created through addition polymerization?
Which of the following polymers has applications in making flexible pipes and toys?
Which of the following polymers has applications in making flexible pipes and toys?
Which polymer is known for its strength and is often used for making bottles and plastic bags?
Which polymer is known for its strength and is often used for making bottles and plastic bags?
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What characteristic distinguishes semi-synthetic polymers from natural and synthetic polymers?
What characteristic distinguishes semi-synthetic polymers from natural and synthetic polymers?
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Which type of polymer is often used for making inner insulation in coaxial cables?
Which type of polymer is often used for making inner insulation in coaxial cables?
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Which of the following is NOT a characteristic of thermosetting plastics?
Which of the following is NOT a characteristic of thermosetting plastics?
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Which of the following materials is classified as a thermoplastic?
Which of the following materials is classified as a thermoplastic?
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Which polymer is primarily used in the construction of non-stick surfaces on cookware?
Which polymer is primarily used in the construction of non-stick surfaces on cookware?
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What type of polymer is composed of two or more different monomer subunits?
What type of polymer is composed of two or more different monomer subunits?
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Which additive is primarily used to give color to plastics?
Which additive is primarily used to give color to plastics?
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Which statement about vulcanized rubber is true?
Which statement about vulcanized rubber is true?
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What are petrochemicals primarily derived from?
What are petrochemicals primarily derived from?
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Which of these materials is considered a thermoplastic?
Which of these materials is considered a thermoplastic?
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What is a primary function of stabilizers in plastics?
What is a primary function of stabilizers in plastics?
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Which of the following statements about thermoplastics is incorrect?
Which of the following statements about thermoplastics is incorrect?
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Which type of polymer is formed through the loss of small molecules during its formation?
Which type of polymer is formed through the loss of small molecules during its formation?
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What distinguishes thermosetting plastics from thermoplastics?
What distinguishes thermosetting plastics from thermoplastics?
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Which of the following is an example of a natural polymer?
Which of the following is an example of a natural polymer?
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Which factor primarily influences the classification of polymers as fibers?
Which factor primarily influences the classification of polymers as fibers?
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What is a key characteristic of elastomers?
What is a key characteristic of elastomers?
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Which of the following polymers does NOT fall under the thermoplastic category?
Which of the following polymers does NOT fall under the thermoplastic category?
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How do condensation polymers differ from addition polymers in their structure?
How do condensation polymers differ from addition polymers in their structure?
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Which of the following is a synthetic polymer used widely in various applications?
Which of the following is a synthetic polymer used widely in various applications?
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Study Notes
Examples of Common Polymers
- Low-density polyethylene (LDPE) is used for squeeze bottles, toys, flexible pipes, and insulation covers for electric wires.
- High-density polyethylene (HDPE) is used for bottles, pipes, inner insulation of coax cable, plastic bags, and other applications.
- Polypropylene (PP) is used for auto parts, industrial fibers, food containers, bag liners, dishware, and textile/food wrapping.
- Polystyrene (PS) is used for petri dishes, CD cases, and plastic cutlery.
- Polytetrafluoroethylene (PTFE) is used for low friction bearings, non-stick pans, inner insulation of coax cables, and coatings against chemical attack.
- Polyvinyl chloride (PVC) is used for pipes, fencing, lawn chairs, handbags, curtains, non-food bottles, raincoats, toys, vinyl flooring, and electrical installation insulations.
- Styrene Butadiene Rubber (SBR) is used as an adhesive and bonding agent.
Classification of Polymers
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Based on Origin of Source:
- Natural polymers: Found in nature, e.g., cellulose, rubber, proteins.
- Semi-synthetic polymers: Modified natural polymers, e.g., rayon, cellophane.
- Synthetic polymers: Man-made polymers, e.g., polyethylene, nylon.
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Based on Structure:
- Linear polymers: Long, straight chains.
- Branched chain polymers: Have side chains attached.
- Cross-linked polymers: Chains connected by chemical bonds.
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Based on Molecular Forces:
- Elastomers: Highly elastic, can stretch and return to original shape, e.g., rubber.
- Fibers: Long, thin strands with high tensile strength, e.g., cotton, nylon.
- Thermoplastics: Soften on heating and solidify on cooling, recyclable, e.g., polyethylene, nylon.
- Thermosets: Harden irreversibly on heating, strong and durable, not recyclable, e.g., Bakelite, epoxy resins.
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Based on Mode of Polymerization:
- Addition polymerization: Monomers add to form polymer without releasing small molecules, e.g., polyethylene, PVC.
- Condensation polymerization: Monomers react, releasing small molecules like water, e.g., nylon, polyester.
Mechanism of Addition Polymerization
- In this process, monomers add together without losing small molecules.
- The polymer formed is an exact multiple of the monomer unit.
- Examples: Polyethylene, PVC, polypropylene.
Classification of Polymers Based on Mode of Polymerization
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Condensation Polymers:
- Monomers react with loss of small molecules like water or HCl.
- The polymer is not an exact multiple of the monomer unit.
- Examples: Nylon, PET, Bakelite, Melamine-formaldehyde resin.
Classification of Polymers Based on Molecular Forces
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Elastomers:
- High elasticity, tensile strength, flexibility, and resilience.
- Return to original shape after deformation.
- Examples: Natural rubber, polyurethanes, polybutadiene, silicone.
Classification of Polymers Based on Molecular Forces
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Fibers:
- Long, thin strands with high tensile strength, flexibility.
- Used in packaging, textiles, and non-woven fabrics.
- Examples: Natural fibers - cotton, wool, silk. Synthetic fibers - polyester, nylon, acrylic.
Classification of Polymers Based on Molecular Forces
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Thermoplastics:
- Soften on heating and solidify on cooling.
- Held together by weak intermolecular forces.
- Can be reshaped and recycled.
- Examples: Polyethylene, nylon, polyvinyl chloride.
Classification of Polymers Based on Molecular Forces
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Thermosets:
- Harden irreversibly on heating.
- Molecules form a rigid, cross-linked network.
- Strong, durable, and resistant to heat.
- Not recyclable.
- Examples: Vulcanized rubber, Bakelite, polyurethane, epoxy resin, vinyl ester resin.
Difference Between Thermoplastics & Thermosetting Plastics
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Thermoplastics:
- Formed by addition polymerization.
- Linear polymer chains.
- Soften on heating, stiffen on cooling.
- Can be remolded.
- Usually soft, weak, less brittle.
- Recyclable.
- Soluble in some solvents.
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Thermosetting Plastics:
- Formed by condensation polymerization.
- Three-dimensional network structure with strong covalent bonds.
- Do not soften on heating.
- Cannot be remolded.
- Typically hard, strong, more brittle.
- Not recyclable.
- Insoluble in most solvents.
Copolymers
- Homopolymers: Synthesized from a single type of monomer.
- Copolymers: Composed of two or more different monomer subunits linked together.
Plastic Additives
- Pigment: Adds color.
- Stabilizer: Prevents degradation (breakdown).
- Lubricant: Makes molding easier.
- Filler: Adds strength.
- Plasticizer: Increases flexibility.
Videos
- Learn about the history and discovery of vulcanized rubber, nylon, and Bakelite.
Petrochemicals
- Derived from natural gas liquids and oil refinery streams.
- Used to make plastics, fibers, and other synthetic materials.
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Description
This quiz explores various common polymers, detailing their applications and classifications. You'll learn about materials like LDPE, HDPE, and PVC, including where they are commonly found. Test your knowledge on the properties and uses of these important substances.
