Polymers and their Properties

C2: Chapter 2

Learning Objectives• To be able to list and state uses of commonly used

polymers

• To be able to recall and describe the conditions required for the production of LDPE, HDPE, thermosetting and thermosoftening polymers

• To be able to explain how the properties of polymers arise

• CHALLENGE : To be able to apply your understanding of intermolecular forces to thermosetting and thermosoftening polymers

Starter Activity What do you remember from year 10?

Polymers

What is a single unit

of a polymer called?

Where do polymers

come from?

Can you define a

polymer?

Can you name some examples?

5 minutes

Polymers• Polymers are made of

monomer units

• Monomers undergo a polymerisation reaction and make polymers

• A polymer is a substance made from large molecules made up of many repeating units (monomers).

LO1:To be able to list and state uses of commonly used polymers

Polymer Party VideoDraw and fill in this simple chart as we watch a

short video on polymers

LO1:To be able to list and state uses of commonly used polymers

Name of Polymer Name of Monomer Uses of Polymer

Natural vs. Synthetic Polymer QuizNATURAL SYNTHETIC

LO1:To be able to list and state uses of commonly used polymers

WOOLCarpert and Clothing

LATEXGloves, Condoms, Balloons

POLYESTERClothing, Seat Belts, Blankets

NYLONClothing, Fishing Lines

SILKClothing, upholstery and parachutes

TEFLONCable insulator, non stick pans

Polymer Research Activity• Use the exercise books to complete the table

15 minutes15 minutes

EXTENSIONPolymer Exam Question

LO2:To be able to recall and describe the conditions required for the production of LDPE, HDPE, thermosetting and thermosoftening polymers

Peer MarkLDPE HDPE Thermosoftening Thermosetting

Structure Low density branched chains which prevent tight packing

High density straight chains which allow for

tight packing

Long straight chains that are all tangled

Rigid structure with fixed chains

Bonding and Forces

Weak intermolecular

forces

Strong intermolecular

forces

Weak intermolecular forces that are

easily broken with heat

Strong covalent bonds linking

chains together (cross links) don’t

break when heatedFormation High pressure

(and trace oxygen)Low pressure

(and catalyst at 50oC)

N/A N/A

Properties Weak structure with low melting

points

Strong structure with high melting

point

Soften when heated and can be remoulded

Do not soften when heated, just burn.

LO2:To be able to recall and describe the conditions required for the production of LDPE, HDPE, thermosetting and thermosoftening polymers

Key Question

How do the properties of polymers arise?What do the properties depend on?

Discuss with the person next to you

HINT: LOOK AT YOUR TABLE, think about our lesson on alloys!

LO3:To be able to explain how the properties of polymers arise

2 minutes2 minutes

Polymer Properties

• The properties of a polymer depend on:– The monomers used to make it– The conditions under which the polymer is made– The strength of the forces between molecules

LO3:To be able to explain how the properties of polymers arise

Prediction Challenge

Based on your understanding of intermolecular forces and the structure of polymers, DRAW

what you think thermosoftening and thermosetting polymers look like

CHALLENGE : To be able to apply your understanding of intermolecular forces to thermosetting and thermosoftening polymers

2 minutes

Thermosoftening vs. Thermosetting

• Thermosoftening• Polymer chains are easy to

separate• Forces broken when heated • When polymer cools forces

pull the molecules back together

• Thermosetting• Chains fixed together by

strong covalent bonds• Bonds stop the chains

separating• When heated strongly the

polymer will burn/char.

CHALLENGE : To be able to apply your understanding of intermolecular forces to thermosetting and thermosoftening polymers

Plenary• The polymer chains in a thermosoftening

polymer form a web. The polymer softens at relatively low temperatures. Other polymers have strong bonds between their chains which form

. We call these polymers.

Covalent Thermosetting Tangled Cross Links

tangled

covalent

cross links

thermosetting

5 minutes