1. Polymer Chemistry (Part 1) OER Created & Presented Dr. Rajdip Deyby
Dr. Rajdip Dey
Techno India Salt Lake
Kolkata

2. Polymers Content: Introduction: What are they? Types of Polymers
Uses and Applications of Polymers
Summary

3. Polymers - What are they?
Polymers are a special kind of macromolecule
The word polymer comes from the Greek words “poly,” meaning “many”, and “meres,” meaning “parts” or “repeating units”
A Polymer consists of a large chain of repeating molecules (monomers) that are attached in an end to end fashion

4. Sources of Polymers Oil (carbon) Sustainable sources (biopolymers)
4% of crude oil is used for plastics
Sustainable sources (biopolymers)
Wheat & corn
Carrot
Recycling
Difficult: all recycled items must be of the same polymer
Mixed plastics can be used for low level products such as road surfacing, wood replacement

5. Description of Polymers
Imagine a string of beads
Each bead is identical (for example, red sphere)
Represents the “mer”
The string can contain 100’s of beads
Represents the “poly” characteristic
The string in between the beads represents the chemical bond between monomers

6. Length of Polymers Polymer chains are HUGE!
Polymers typically consist of between 20,000 and 40,000 individual monomers
If each bead on the string of beads were one inch apart, one polymer molecule could be as long as 10 football fields!!!
This chain length is what gives the polymer most of its desirable characteristics

7. Description of Polymers
Polymer chains are flexible, and usually “clump” together into a smaller shape
This enables the individual chains to interact and become entangled
This helps to give a polymer its strength and flexibility

8. Types of Polymers There are two main types of polymers Natural
(cotton, silk, wood, leather…)
Synthetic
(plastics, nylon, latex…)

9. Synthetic Polymers There are two basic types of synthetic polymers
Thermoplastics (plastics, Styrofoam)
These can be softened by heating and hardened by cooling - easily recycled
Can easily be cast into various shapes
Thermosets (epoxy’s, adhesives)
These harden after being heated
Can easily be cast into different shapes
Cannot be reformed

10. Thermosetting Plastics
15% of plastic production
Polyurethane
Carpet underlay
bed foam
Urea formaldehyde (UF)
Mains plugs/sockets/light switches
Phenol Formaldehyde (PF)
Tradename: Bakelite
Epoxy Resin
Tradename: Araldite
Used as coatings & adhesives or to form composites eg. Carbon fibre
Can cause health problems
Melamine formaldhyde
Work top laminates
Office furniture
Thermosetting Plastics

11. Types of Polymers - Copolymers
Most polymer chains are made up of one type of monomer (for example, red beads)
However, some polymers are made up of different types of monomers (for example, blue and red beads) - these are called copolymers

12. Copolymers There are four main types of copolymers
The different monomers can be arranged either in an alternating or random fashion
Alternating
...-red-blue-red-blue-red-blue-red-blue-red-…
Random
…-blue-red-red-blue-red-blue-blue-red-blue-…

13. Copolymers There are also block copolymers and graft co-polymers Block
…-R-R-R-R-R-R-B-B-B-B-B-B-R-R-R-R-R-R-…
Graft
…-R-R-R-R-R-R-R-R-R-R-R-R-R-R-R-R-R-… |
B-B-B-B-B-B-B-B-B-…

14. Polymers - Pros and Cons
A polymer has many very advantageous properties. Polymers are:
Lightweight
Strong and durable
Cheap
Easy to manufacture
Unfortunately, polymers do not easily biodegrade and end up producing large amounts of waste

15. Uses of Polymers
Polymers are incorporated into nearly every aspect of daily life
Entertainment
Sports
Clothes
Hobbies/Toys
Household products
Automotive

16. Carbon Based Polymers PolyPropylene (PP) Poly Vinyl Chloride (PVC)
Tupperware (lunch boxes)
Poly Vinyl Chloride (PVC)
Window frames
PolyStyrene (PS)
Packaging
Yoghurt pots / vending machine cups

17. Carbon Based Polymers Acrylic Paint Point of sale displays Baths
Car lights
HDPE (High Density PE)
Bottles (biggest application)
milk bottles (largest bottle sector)
LDPE (low Density PE)
Supermarket carrier bags
Packaging film (eg. cling film)
Washing up liquid bottles
PET (PE Terephthalate)
fizzy drinks bottles
Carbonation makes HDPE unsuitable
Space blankets
ABS (Acrylonitrile Butadiene Styrene)
Car batteries
Calculators / mobile phones
Safety helmets

18. Material Properties: ABS
Amorphous
Good resistance against medium temperatures (< 1000C)
Hard
tough
antistatic.
good resistance against chemicals.
Poor resistance to UV-light
Can be painted
Min temp: -250C
Max Temp: 800C
Glass Temp: 1100C

19. Material Properties: PET
Very light
AKA: Polyester
Can stand high tensile stress
Often used for magnetic tape
hard, stiff, strong
dimensionally stable
absorbs very little water
good chemical resistance except to alkalis
Medium resistance to UV
most commonly recycled plastic
drinks bottles are made from PET
Semi-crystaline
Must be rapid cooled to make it amorphous & transparent
Can degrade & become discoloured during heat treatment
Adds an unwanted flavour to food (can be compensated for at addition cost)
Min Temp: C
Max Temp: C
Glass transition temperature: 82oC.
Melting point: oC.

20. Polymer Chemistry A polymer chain is built on a Carbon backbone
A monomer unit consists of a small carbon chain attached to a specific type of functional group
The functional group is what gives each polymer chain its individual characteristics

21. Polymer Chemistry
As previously stated, polymer chains interact with one another, becoming entangled
Polymer chains also form cross-links with adjacent chains, which allows the polymer to hold its shape and gives added strength

22. Summary
Polymers are made up of large chains of repeating units, called monomers
Individual chains interact to form a stronger overall substance through entanglements and cross-links
Polymers are incorporated into almost every aspect of daily life
Polymers are lightweight, strong, and inexpensive