Introduction Activity 1: Changing Polymer Pellets Activity 2: Hunting for Polymer Products Activity 3: Comparing the Viscosity of Liquids Activity 4: Testing the Strength of Different Polymer Films Activity 5:Measuring Strength of Different polymer Films Design Project: Designing a Humidity Sensor Polymer Product: Design a new product

1. YOUNG SCIENTIST CENTER
POLYMERS
BY: ENG. ABDALFTAH ALI
abdftah1994@gmail.com

2. OUTLINE
Introduction
Activity 1: Changing Polymer Pellets
Activity 2: Hunting for Polymer Products
Activity 3: Comparing the Viscosity of Liquids
Activity 4: Testing the Strength of Different Polymer Films
Activity 5:Measuring Strength of Different polymer Films
Design Project: Designing a Humidity Sensor
Polymer Product: Design a new product

5. What is a polymer?
what are the main
types?
Examples and practical
applications!!
02

14. ACTIVITY (1): Changing Polymer
Pellets

15. 13
Do you know that our world is facing
a scarcity of fresh water?
A lot of people do not have access to
clear water.
Do we know that there the water that
falls on land evaporates or runs off?
Runs off can cause soil erosion and
carry away nutrients from the soil,
making the soil less fertile.
Many cities have low limits on using
water, especially for gardens in the
morning hours and evening. Why?
Do we need to conserve water?
Reservoirs??

17. Changing Polymer Pellets:
Objective:
Compare and test the appearance and mass of polymer pellets
before and after soaking them in plain water.
PREDICTIONS:
What will happen to the pellets when they are plain in water?
What causes this change?
Why does this happen?

19. Materials:
➢ 1 g polyacrylamide pellets(soil
moist)
➢ Three 150 ml beakers
➢ 10 ml graduated cylinder
➢ 10 ml water
➢ 10 ml saturated salt water.
What do we
need??

20. Procedure, Data and observation
1
Steps
2
Steps
3
Steps
4
Steps
Prepare two 0.5g samples
of polymer pellets,
Each one is separated in
the beaker!
Add 10 ml of plain water
to each beaker and
mixture it for 10 minutes
Remove the sample and
put them dry with a paper
towel. Measure and but it
back again
For comparison, add 10 ml
of plain water and
saturated salt water to
two samples and mixture
them for 10 minutes.

22. Interpretation of data
How did the pellets change
when they were initially
placed in plain water?
How the addition of
pellets to soil could
provide plants with a
supply of water?
Why do pain water and
salt water have different
effects?
How did salt water affect
the pellets?
1- swelled within minutes because absorbed water
2- slat water caused the swollen pellets to release some of the absorbed water
and shrink significantly.
3- salt water has a lower concentration of water molecules.
4- pellets act as reservoirs, storing and releasing when needed!

23. THE RESULT
• The polymer pellets swell and increase in mass when
immersed in plain water, indicating that they absorbed
water.
• When the swollen polymer pellets are re-immersed in
plain water, they continue to absorb water and increase
in mass.
• When the swollen polymer pellets are immersed in salt
water, they shrink and decrease in mass indicating that
the pellets released the absorbed water.

24. Why do the polymer
pellets in the activity
absorb water?
Why does salt affect their
absorption of water?
Let’s read more here

25. Activity(2): Hunting for polymer products
we have learned that there are two types of polymer whether
natural or synthetic.
Polymers are found in most of the products we use every
day.!
Polymers around us!!!
let’s categorize and label products in our lecture room on
polymer types.
Let’s look at our day!!
Objective: compile a
list of products made
of polymer and
describe the uses of
polymer products!

26. Activity (2): Hunting for
polymer products
Time for reading(introduction)
!!!!
“The man who never reads lives
only one” George R.R. Martin
Quick
summary!!

28. Activity 2
• Could you Describe the differences or similarities
between natural and synthetic polymers?
• Strength, texture, opaqueness, and density!!!
• Why do you think different polymers have different
properties?
• Might the properties of polymer determine the way in
which it is used?
• What might be the advantages of making each product
from synthetic polymers and the disadvantages?
• What new questions do you have about the polymers .
• why do you want to know about them?

29. Time for reading!!
Polymers properties and differences!

31. Activity(3):
Comparing The
Viscosity Of Liquids

32. • In activity 2, we discovered there are different
properties of the polymer, today we will focus
on one of them, the viscosity.
• What does viscous mean??
• The more viscosity a liquid is, the longer the
liquid takes to flow and the longer.
• It depends on the strength of the intermolecular
forces between the particles that make up the
liquid.
• Generally, liquids with higher viscosities flow
more slowly than those with lower viscosities.
Introduction

33. • There are different methods for measuring viscosity, such as using a
viscometer.
• The most common method is probably the use of a viscometer.
• If we drop a marble into a glass of water, honey which one will move
quicker?

35. Objective: compare the viscosity of three liquids that have similar
chemical structures but different molecular structures
Let’s think about the activity before: how can you tell
whether one liquid is more viscous than another?
Why do liquids vary in viscosity?
How does the viscosity of polymers affect the ways in
which they can be used?
• Coatings, paints, and varnishes.
• The molecular weights of the liquids are measured
by atomic mass units.
• An atomic mass unit is equal to 1.66*10(-24).gram.
• The following chart will show the name of liquids,
chemical structures, and molecular weights.
• Which liquid do you think is the most viscous?
The least vicious?
Materials:
Sealed vial of methanol, ethylene glycol, and glycerol.
Stopwatch.
Name of
liquid
Chemical
structure
Molecular
weight
methanol CH3OH 32
Ethylene
glycol
OHCH2CH2OH 62
glycerol OHCH2CH(OH)
CH2OH
92

36. Procedure, Data and observation
1
Steps
2
Steps
3
Steps
Examine the liquid in
each vial
Turn over one of the
vials. Record how long
takes for the air bubble
to, Record your
observation.
Repeat step 2 for each
of the other two vials.

38. Interpretation of the data.
• What is the order of viscosity of the three liquids?
• How does the viscosity of the liquids relate to the
molecular weight of the liquids?
• What prediction would you make about the viscosity
of the liquids with similar chemical reactions and
different inn molecular weights?
• Molecular weights of the liquids increase so does the
viscosity of the liquid.

40. The Result:
➢ The air bubble will move the fastest through the methanol and
the slowest through the glycerol.
➢ Why most of the polymers are solid and why does polymer
molecular weight affect the viscosity of polymer solutions?
➢ Let’s answer all those questions after reading the last part.

41. Introduction:
ACTIVITY(4):
TESTING THE
STRENGTH OF
DIFFERENT
POLYMER FILMS
❖ As the material is stretched, its molecules or atoms change
position slightly.
❖ When the material is released, the particles return to their normal
position.
❖ Tensile strength is the amount of stretching that a material can
withstand before it deforms permanently ( the particles do not
return to their normal position ) or ruptures.
❖ polymer films are made by dissolving a polymer in a solvent and
then casting the polymer solution into a flat surface.
❖ Another way of making polymer films is by a process called
extrusion.
❖ In this process a solid polymer passed through a long tube where
it’s heated and melted.

43. Objective: cast polymer films that vary in molecular weight of the polymer. Also, test and compare the hardness
stretchability, and tensile strength of the films.
Why knowing the strength of polymer is important?
What is the relationship between the stretchability of a polymer film and its strength?
How does molecular affect the strength of polymer films?
What properties of polymer films make them useful in products?
Materials:
• 6 glass micro slides
• Wax pencil.
• 3 pipettes with bulbs.
• Centimeter ruler.
• 3 large coins
• Single-edge razor blade.
• Paper clip.
• polyvinyl with the molecular weights:
• 100000 amu
• 170000 amu
• 260000 amu

44. What polymer film do you predict will be the hard one and which one will be most stretchable?
Do we remember activity (3) that we used, where it was the most viscosity polymer solution?

45. procedures
dispense the solution from
the pipette as evenly as
possible onto the unlabeled
side of one of the slides.
repeat steps 2 and 3 to
make a second polymer
film.
using a pipette draw the
appropriate polyvinyl
acetate solution to the mark
you labeled
label two micro slides with
the molecular weight of one
of the polyvinyl acetate
solutions.

46. Procedures
repeat the above steps to
make the other films.
peel off one of the films
made and test the hardness
by scratching on the paper
clip.
repeat steps 1-4 for each of
the other two polyvinyl
acetate solutions.

47. Rank the three films
according to their
hardness, and
according to how
easily they could be
stretched?
The film made of
polyvinyl acetate
260000 is the hardest
and most difficult to
stretch. And 100000 is
the softest and easiest to
stretch
How does your
observation
compare with your
predictions?

50. 1- Clamp a ring to a ring stand.
2- attach two paper clips to a weight
3- fold the film lengthwise into thirds.
4- insert a spatula through the two wire loops of one of the binder clips
attached to the film.
5-Hang the weight and hook the paper clips through one of the wire
loops of the two clips.
6- remove the weight and record the appearance of the film.
7- Test the strength of the other two films.
PROCEDURES

52. THE RESULT
The film made of poly ( vinyl acetate ) M.W. 100,000 stretches the
most when a weight is hung from the film and, therefore, is the
weakest of the three films. The film made of poly ( vinyl acetate )
M.W. 260,000 stretches the least and, therefore, is the strongest of
the three films.

53. • Compare the predictions with the result.
• What is the relationship between the tensile strength of a polymer film and the
molecular weight of the polymer?
• How did the molecular weight of the polymer influence the behavior of the films
after the weight was removed from the films?
• Compare your predictions with the results of the activity. Were you surprised by
any of your results? Explain.
• What new questions do you have about the strength of polymer films or about
polymer films in general?
• Write down three or more questions you have. Give a reason for asking each
question.

54. Time for reading now!!
Let’s understand more about the concept
Last part!

55. Activity(5):
Measuring water
absorption by
different polymer
films
Objective: This activity will explore
factors that affect water absorption by
polymer films.

56. Introduction:
• How can measure the amount of water a film has
absorbed?
• What affects a film’s ability to absorb water?
• How might a polymer film’s ability to absorb
water influence how it is used in the design of a
product?
• The structures of the polymers and their
molecular weights are shown below. Which of
the films will absorb the most water? The least?
Will any of the films not absorb any water? If so,
which one ( s )? Record your predictions and
your reasons for making them.

57. ▪ Safety glasses, gloves, and apron
▪ Masking tape
▪ wax pencil
▪ 5 small watch glasses centimeter ruler
▪ 5 pipettes with bulbs
▪ Balance 3 beakers of water
▪ paper towels
▪ plastic wrap
▪ polymer solutions :
▪ poly ( vinyl acetate ) M.W. 100,000 ▷ m.W.
170,000 > m.W. 260,000
▪ Poly ( vinyl alcohol ) m.W. 2,000
▪ polystyrene (m.W. 190,000 )
▪ Clock or watch with second-counting
capability
MATERIALS:

61. Interpretations of the Data
Rank the five films according to
the total amount of water each
film absorbed.
What was the effect of monomer
type on water absorption by the
polymer films?
What is happening at the molecular
level when a polymer film absorbs
water?
How did the absorption rates of
the three poly ( vinyl acetate )
films vary with molecular
weight?
01
02
03
03

62. Summary of Experimental Results
• The polystyrene film absorbs virtually no water.
• The poly ( vinyl alcohol ) film absorbs so much water that
it eventually dissolves in the water.
• The poly ( vinyl acetate ) films absorb water, but not so
much that they dissolve in the water.
• The three poly ( vinyl acetate ) films, which differ in the
molecular weight of the polymer, absorb water at different
rates.
• The lower the molecular weight of the poly ( vinyl acetate
), the faster the water is absorbed.

63. Design project(1): Designing a Humidity Sensor!
❖ Students construct a set of prototype humidity sensors in the
form of polymer films. The films are embedded with cobalt(11)
chloride, which changes color as the surrounding humidity
changes.
❖ To meet specific criteria, students make several choices
regarding the design of their prototypes.
❖ Students test and evaluate their prototypes and redesign them
again to make them more effective.

64. Introduction
What do you know about humidity sensors?
It’s a device that detects the moisture and level of
surrounding air.
Using what we learned about polymer in the activities
design a nonelectric sensor.

65. Design challenge
Your goal is to design a humidity sensor made the design
of a polymer film that changes color as the challenge
moisture level in its environment changes.
Since a humidity sensor depends on many factors, polymer
type being just one of them, numerous prototypes are
possible.
Think about these questions on your work you prototypes:
Which of the polymers will absorb and release water
easily and reversibly?
How thin should the films be? How many indicators
should be used?
What kinds of tests need to be performed to show whether
the sensor is effective or not?
Why do you think we use polyvinyl acetate?

66. humidity's in the sensor are 0%-room about 50%, and humidity at
100%.
At 100% humidity, the cobalt chloride should be completely
hydrated and appear pink, and the sensor should transmit the
lightest.
In 0 % humidity, the cobalt ( II ) should be anhydrous and appear
blue, and the sensor should transmit the least light.
In 50 % humidity ( room humidity ), the cobalt ( II ) should be
partly hydrated and appear purple, and the sensor should transmit
about half as much light as at 100% humidity.

67. Based on following criteria
The responses of the sensor must be
reversible when moved from a dry
environment to a humid environment and
back to a dry environment
The sensor must be transparent in order for
the light to be able to pass through the
sensor in a spectrophotometer.
The sensor must be a thin polymer film
made of one of these three polymers: poly (
vinyl acetate ) M.W. 100,000; poly ( vinyl
acetate ) M.W. 260,000; or poly ( vinyl
alcohol ) M.W. 2,000.
Cobalt ( II ) chloride, which is blue when
dry and pink when wet, must be used as the
indicator in the sensor.
The sensor must give a visual response to changes in
humidity within 10 minutes when placed in dry, 100 %
humidity, and room-humidity environments.
The sensor must be durable: it should not
crack, chip, or peel off its support.

68. Procedure for constructing prototypes
▪ You can record the steps you will follow to make the prototype. Materials you need and any problems

69. Procedure for testing the prototypes:
• Remember each type must be tested in three environments, dry, room, and 100% humidity.

70. INTERPRETATIONS OF DATA
After taking all the criteria which prototype you performed the best? The worst?
Are there any factors you did consider when you
Made your prediction? Explain.

71. PRESENT YOUR PROTOTYPE AND THE RESULTS OF YOUR TESTS
• Show your prototype to your classmate and explain how you interpret it.
• The classmate should evaluate your prototypes.
• Based on what you learned redesign your prototype again.
• Prepare your final report.

72. Designing a new polymer product
Project Objectives:
➢ apply concepts they learned about polymers
from doing previous activities in the module.
➢ design, construct, test, evaluate, and
redesign prototypes of a new polymer
product.

73. Introduction
The main ideas in the article.
Summary of the previous activity's concepts.

74. Your goal is to design a new polymer product. It may be an
improvement of an old idea, or it may be entirely new.
Whatever the product is, it must serve a practical purpose.

75. Proposals Prototype
• Do you remember activity 2, and all the products
we have seen?
• Any of those products may need improvement!
• The previous criteria will be taken into our
consideration

76. Use all the Design-Log Sheets 1-9