POLYMERS

Maria Clérigues

Juanjo Arbona

Daniela Hurtado

Maria Medina

Aitor Marquez

Daniel Rodriguez

What is a polymer?Polymers are organic macromolecules formed by the

union of monomers in a chemical process called polymerization.

Types of polymersThere are natural and synthetic polymers

Low density polyethylene is

an "addition polymer", formed by repeating units

of ethylene.

LOW-DENSITY POLYETHYLENE:

Properties• Good thermal and chemical resistance.• Good impact resistance.• It can be transparent, depending on its thickness.• It can be processed by the methods used for forming thermoplastics.• It is more flexible than HDPE.• It presents difficulties to print, paint or paste on it.

Applications

• Plastic bags.• Film for greenhouses and other agricultural uses.• Toys.• Household items : cups, plates, cutlery ...• Bottles.• Stretch film to pack pallets.• Cable sheathing.

HIGH-DENSITY POLYETHYLENE

It’s a thermoplastic

polyethylene made by petroleum. It

takes 1.75 kilograms of

petroleum to make one kilogram of

HDPE.

Properties• It has stronger intermolecular forces.• More tensile strength than low-density polyethylene.• It is harder and more opaque than low-density polyethylene.• Can withstand higher temperatures.• HDPE contains the chemical elements carbon and hydrogen.

Applications

• Arena board.• Portable basketball system bases.• Bottle caps.• Breast implants.• Telecom ducts.• Ballistic plates.

POLYPROPYLENE:Is a thermoplastic polymer, partially

crystalline, obtained from the

polymerization of propylene. It belongs

to the group of polyolefin and it is

used in a wide variety of

applications.

•Low density•High softening temperature• High resistance to stress cracking•Great tendency to be oxidized (problem usually solved by the addition of antioxidants)• It has a degree of crystalline intermediate between the high-density polyethylene and low density.

Properties

Applications•Molding of a wide variety of items; toys, bumpers of cars…• Blow molding hollow containers: bottles, fuel tanks…•Thermoformed food containers for applications that require resistance to high temperatures (microwave) or low temperature (frozen).•Fiber production•Extrusion profiles, sheets and tubes•film production•Medical or pharmaceutical applications

POLYETHYLENE TEREPHTHALATE:

"PET" is a type of plastic obtained by a polycondensation reaction between terephthalic acid

and ethylene glycol. Belongs to the so-called synthetic

polyesters.

Properties• High transparency, but can be tinted• High stiffness• High resistance to wear and corrosion.• Good chemical and thermal resistance.• Excellent barrier to CO2, O2 and acceptable moisture barrier.• Recyclable.• It can be in contact with food.• Good electrical insulator

Applications

• Bottles• Rigid cans• Industrial fiber: ropes, fabrics…• Films for food packaging• Films for motors isolation

POLYVINYL CHLORIDE

Known member of the family of

thermoplastics. It is a polymer

derived from two natural raw materials:

sodium chloride and petroleum.

• Very good electrical resistance.• Ductile and tenacious. • High resistance to abrasion.• Stable and inert.• It can last up more than sixty years.• Low cost of installation.

Properties

Applications

• Construction: portable water pipes, windows, doors, electrical conduit and telecommunications, wall papers…• Water bottles• Films : candy, foods…• Jars: food, cosmetics…• Blisters: drugs, sundries…• Parts of electrical appliances• Plugs• Insulation of wires

POLYSTYRENE

.

It is a thermoplastic polymer that is obtained of the

polymerization of the styrene. There are

four types of polystyrene: the PS

crystal, the polystyrene of high

place in the environment, the

expanded polystyrene and the polystyrene

extrudate.

• It presents the lowest thermal conductivity of all the thermoplastics.• It hasn’t got resistance to the temperature.• The polystyrene has very low electrical conductivity.•It can float in the water.

Properties

Applications

• It’s a material very cheap.• It is in use like insulating thermal and acoustic.• It uses as thermal isolation in soils• It is used for the production of disposable packings.

QUESTIONARY ANSWERS

1. Which are the main characteristics of a polymer?•Organic•High molecular weight•Changeable shape

2. We know that an element is organic because it is formed by carbon.

3. Which of those polymers are natural? Which are synthetic?

Natural Natural Natural NaturalSynthetic Synthetic Synthetic Synthetic

4. Write two differences between low-density polyethylene and high-density polyethylene:

•High-density polyethylene is harder than low-density polyethylene•Low-density polyethylene is more flexible than high-density polyethylene

THERE ARE MORE THAN THOSE POSSIBILITIES

5. High-density polyethylene is made by petroleum.

6. Polypropylene is obtained from the polymerization of propylene.

7. Are those affirmations about the propylene true or false?

8. “PET” is a type of plastic obtained by a polycondensation reaction between terephthalic acid and ethylene glycol.

9. Write two applications of polyethylene terephthalate: - Films for food packaging - Films for motors isolation

THERE ARE MORE THAN THOSE POSSIBILITIES

True The polypropylene has low density

False It has worse tendency to be oxidized

True Polypropylene has high resistance to stress cracking

10. Polyvinyl chloride is derived from sodium chloride and petroleum.

11. Write some principal uses of the polyvinyl chloride are: Construction, Films, Jars, Blisters, Plugs…

12. Which are the four types of polystyrene?PS crystal, Polystyrene of high place in the environment, Expanded polystyrene and Polystyrene extrudate.

13. Some properties of polystyrene are… (Choose the correct answers).a) It can float in the waterd) It hasn’t got resistance to high temperatures