Transcript Polymers_NEW

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?
What is a
single unit
of a
polymer
called?
Can you
name some
examples?
Polymers
Can you
define a
polymer?
Where do
polymers
come
from?
LO1:To be able to list and state uses of commonly used polymers
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 Video
Draw and fill in this simple chart as we watch a
short video on polymers
Name of Polymer
Name of Monomer
Uses of Polymer
LO1:To be able to list and state uses of commonly used polymers
Natural vs. Synthetic Polymer Quiz
NATURAL
SYNTHETIC
LATEX
Gloves, Condoms, Balloons
POLYESTER
Clothing, Seat Belts, Blankets
WOOL
Carpert and Clothing
NYLON
Clothing, Fishing Lines
SILK
Clothing, upholstery and parachutes
TEFLON
Cable insulator, non stick pans
LO2:To be able to recall and describe the conditions required for the production of LDPE,
HDPE, thermosetting and thermosoftening polymers
Polymer Research Activity
• Use the exercise books to complete the table
EXTENSION
Polymer Exam Question
LO2:To be able to recall and describe the conditions required for the production of LDPE,
HDPE, thermosetting and thermosoftening polymers
Peer Mark
LDPE
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 heated
Formation
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.
LO3:To be able to explain how the properties of polymers arise
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
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
CHALLENGE : To be able to apply your understanding of intermolecular forces to
thermosetting and thermosoftening polymers
Prediction Challenge
Based on your understanding of intermolecular
forces and the structure of polymers, DRAW
what you think thermosoftening and
thermosetting polymers look like
2 minutes
CHALLENGE : To be able to apply your understanding of intermolecular forces to
thermosetting and thermosoftening polymers
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.
Plenary
• The polymer chains in a thermosoftening
tangled
polymer form
a web. The polymer
softens at relatively low temperatures. Other
covalent
polymers have strong
bonds
cross links
between their chains
which form
.
thermosetting
We call these
polymers.
Covalent
Thermosetting
Tangled
Cross Links