POLYMER

Question 1

Polymers

Answer 1

High molecular weight compounds formed by the repeated union of simple molecules called monomers.

Question 2

Origin of the word Polymer

Answer 2

Derived from Greek words “poly” (many) - “mer” (unit or part).

Question 3

Definition of Polymer

Answer 3

A macromolecule made up of repeating structural units linked by covalent bonds.

Question 4

Process of Polymerization

Answer 4

The formation of polymers from monomers through chemical reactions.

Question 5

Natural Polymers

Answer 5

Found in plants and animals - e.g. rubber - silk - cellulose - and proteins.

Question 6

Synthetic Polymers

Answer 6

Man-made polymers created through chemical reactions - usually derived from fossil fuels.

Question 7

Semi-Synthetic Polymers

Answer 7

Chemically modified natural polymers - e.g. cellulose acetate - vulcanized rubber.

Question 8

Elastomers

Answer 8

Rubber-like polymers with weak intermolecular forces - e.g. Natural Rubber (polyisoprene) - Styrene-Butadiene Rubber (SBR) - Nitrile Rubber (NBR).

Question 9

Fibers

Answer 9

Strong - thread-like polymers used in textiles and construction - e.g. Nylon - Polyester.

Question 10

Liquid Resins

Answer 10

Low-viscosity polymers used in coatings and adhesives.

Question 11

Plastics

Answer 11

Synthetic polymers that can be molded into different shapes.

Question 12

Thermoplastics

Answer 12

Soften when heated and harden when cooled; process is reversible.

Question 13

Thermosetting Plastics

Answer 13

Undergo irreversible chemical changes when heated - forming a rigid structure.

Question 14

Definition of Thermoplastics

Answer 14

Polymers that soften when heated and harden when cooled (fully reversible process).

Question 15

Intermolecular Forces in Thermoplastics

Answer 15

Moderate forces like van der Waals interactions and some hydrogen bonding.

Question 16

Advantages of Thermoplastics

Answer 16

Versatile - durable - impact-resistant - recyclable - easy to reshape - chemically resistant - good electrical insulation.

Question 17

Common Thermoplastics

Answer 17

Polyethylene (PE) - Polypropylene (PP) - Polyvinyl Chloride (PVC) - Polystyrene (PS) - Polytetrafluoroethylene (PTFE).

Question 18

Resin Identification Code

Answer 18

A number system developed by the Society of the Plastics Industry (SPI) to classify plastic types.

Question 19

Polyethylene Terephthalate (PET or PETE)

Answer 19

Formed by polymerizing ethylene glycol and terephthalic acid.

Question 20

Uses of PET

Answer 20

Used in packaging - textiles - and plastic bottles.

Question 21

Properties of PET

Answer 21

Strong - stiff - lightweight - resistant to chemicals and moisture.

Question 22

High-Density Polyethylene (HDPE)

Answer 22

A petroleum-based thermoplastic that resists chemicals and has high durability.

Question 23

Uses of HDPE

Answer 23

Plastic bottles - pipes - containers - and outdoor furniture.

Question 24

Polyvinyl Chloride (PVC)

Answer 24

One of the most widely used synthetic polymers.

Question 25

Uses of PVC

Answer 25

Pipes - flooring - medical tubing - window frames.

Question 26

Properties of PVC

Answer 26

Durable - resistant to chemicals - flame-retardant.

Question 27

Low-Density Polyethylene (LDPE)

Answer 27

A flexible and corrosion-resistant polymer.

Question 28

Uses of LDPE

Answer 28

Plastic bags - squeeze bottles - food packaging.

Question 29

Limitations of LDPE

Answer 29

Not suited for applications requiring structural strength or heat resistance.

Question 30

Polypropylene (PP)

Answer 30

A polyolefin slightly harder than polyethylene.

Question 31

Uses of PP

Answer 31

Food containers - car parts - textiles - ropes - medical applications.

Question 32

Properties of PP

Answer 32

Heat-resistant - flexible - chemical-resistant - lightweight.

Question 33

Polystyrene (PS)

Answer 33

A widely used plastic known for affordability and insulation properties.

Question 34

Uses of PS

Answer 34

Disposable cups - insulation - food containers - electrical insulation.

Question 35

Definition of Thermosets

Answer 35

Polymers that undergo irreversible chemical changes when heated or cured with catalysts.

Question 36

Cross-Linking in Thermosets

Answer 36

Prevents molecular movement after curing - making them heat-resistant.

Question 37

Examples of Thermosets

Answer 37

Phenolics (PF) - Amino Plastics (UF and MF) - Polyester Thermosets (TS) - Epoxies (EP) - Polyimides (PI).

Question 38

Phenolics (PF)

Answer 38

Machinable thermoset plastics with strong physical and chemical properties.

Question 39

Uses of Phenolics

Answer 39

Electrical insulation - automotive parts - construction materials.

Question 40

Properties of Phenolics

Answer 40

Thermally stable - electrically insulating - chemical-resistant.

Question 41

Amino Plastics (UF and MF)

Answer 41

Made from aldehydes and amino compounds.

Question 42

Uses of Urea-Formaldehyde (UF)

Answer 42

Adhesives - coatings - plywood laminates.

Question 43

Uses of Melamine-Formaldehyde (MF)

Answer 43

Heat-resistant materials like countertops - tableware - and electrical components.

Question 44

Polyester Thermosets (TS)

Answer 44

Low-cost materials with high strength-to-weight ratio.

Question 45

Uses of Polyester Thermosets

Answer 45

Automotive parts - HVAC components - electrical applications.

Question 46

Polyimides (PI)

Answer 46

High-performance plastics resistant to heat and chemicals.

Question 47

Uses of Polyimides

Answer 47

Electronics - medical tubing - adhesives - gears - valve seats.

Question 48

Properties of Polyimides

Answer 48

Low creep - high tensile strength - flame-resistant.

Question 49

Epoxies (EP)

Answer 49

A widely used thermoset resin with strong adhesion and mechanical properties.

Question 50

Uses of Epoxies

Answer 50

Coatings - adhesives - composites - electrical applications.

Question 51

Properties of Epoxies

Answer 51

Resistant to moisture - heat - and chemicals.