All about plastics
- Created by: Manyah
- Created on: 25-04-20 13:58
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- Plastics
- What is a plastic?
- A plastic is an material that can be shaped or molded into any form
- What are they made from?
- Plastics are mainly made of oil
- Oil is a carbon-rich raw material, and plastics are large carbon-containing compounds
- Plastics are mainly made of oil
- Can it react chemically?
- Most plastic is chemically inert and therefore will not react with any other substances
- This means that you can store alcohol, water, soap, acid or gasoline in a plastic container without it dissolving the container itself
- How was plastic discovered?
- First discovery
- Second discovery
- In 1846, Charles Schonbein, a Swiss chemist, accidentally discovered another polymer when he spilled nitric acid-sulfuric acid on some cotton
- The resultant polymer, nitrocellulose, could burst into a smokeless flame and was used in the military as an alternative to gunpowder
- In 1870, chemist John Hyatt reacted nitrocellulose with camphor to make celluloid, a plastic polymer
- This was first used in photographic film, billiard balls, dental plates and ping pong balls
- In 1870, chemist John Hyatt reacted nitrocellulose with camphor to make celluloid, a plastic polymer
- The resultant polymer, nitrocellulose, could burst into a smokeless flame and was used in the military as an alternative to gunpowder
- In 1846, Charles Schonbein, a Swiss chemist, accidentally discovered another polymer when he spilled nitric acid-sulfuric acid on some cotton
- Third discovery
- In 1909, chemist Leo Bakeland synthesized Bakelite, the first truly synthetic polymer from a mixture of phenol and formaldehyde
- Bakelite can be molded when hot and solidified into a hard plastic that can be used for handles, phones auto-parts, furniture and jewelry
- The invention of Bakelite led to a whole class of plastics with similar properties, known as Phenolic resins
- Bakelite can be molded when hot and solidified into a hard plastic that can be used for handles, phones auto-parts, furniture and jewelry
- In 1909, chemist Leo Bakeland synthesized Bakelite, the first truly synthetic polymer from a mixture of phenol and formaldehyde
- Fourth discovery
- In the 1930's, a DuPont chemist names Wallace Carruthers invented a plastic polymer made from the condensation of adipic acid and some diaminohexane monomers that could be drawn out into strong fibers like silk
- This plastic became known as nylon
- In the 1930's, a DuPont chemist names Wallace Carruthers invented a plastic polymer made from the condensation of adipic acid and some diaminohexane monomers that could be drawn out into strong fibers like silk
- Plastics can be separated into 2 major categories
- Thermoplastics
- Less rigid than thermosets, thermoplastics can soften upon heating and return to their original form
- They are easily molded and extruded into films, fibers and packaging
- Examples of these plastics include: polyethylene, polypropylene, polyvinyl chloride
- They are easily molded and extruded into films, fibers and packaging
- Less rigid than thermosets, thermoplastics can soften upon heating and return to their original form
- Thermoset or Thermosetting plastics
- Once cooled and hardened, these plastics retain their shapes and cannot return to their original form. They are hard and durable
- Thermosets can be used for auto parts, aircraft parts and tires
- Examples of these plastics include: polyurethane, polyesters, epoxy resins and phenolic resins
- Thermosets can be used for auto parts, aircraft parts and tires
- Once cooled and hardened, these plastics retain their shapes and cannot return to their original form. They are hard and durable
- Thermoplastics
- How are plastics made?
- 1. Prepare raw materials and monomers
- 2. Carry out polymerization reactions
- 3. Process the polymers into final polymer resins
- 4. Produce finished products
- 3. Process the polymers into final polymer resins
- 2. Carry out polymerization reactions
- 1. Prepare raw materials and monomers
- Processes used to create products out of plastic
- Extrusion
- Pellets are heated and mechanically mixed in a long chamber, forced through a small opening and cooled with air or water
- This is used to make plastic films
- Pellets are heated and mechanically mixed in a long chamber, forced through a small opening and cooled with air or water
- Injection Molding
- The resin pellets are heated and mechanically mixed in a chamber and then forced under high pressure into a cooled mold
- This process is used for containers like butter and yogurt tubs
- The resin pellets are heated and mechanically mixed in a chamber and then forced under high pressure into a cooled mold
- Blow molding
- This technique is used in conjunction with extrusion or injection molding. The resin pellets are heated and compressed into a liquid tube
- The resin goes into the chilled mold , and compressed air gets into the tube, which expands the resins against the edges of the mold
- This process is used to make hollowed items and bottles
- The resin goes into the chilled mold , and compressed air gets into the tube, which expands the resins against the edges of the mold
- This technique is used in conjunction with extrusion or injection molding. The resin pellets are heated and compressed into a liquid tube
- Rotational molding
- The resin pellets are heated and cooled in a mold that can be rotated in 3 dimensions. The rotation evenly distributes the plastic along the walls of the mold
- This technique is used to create long, hollow plastic items such as toys, furniture and sports equipment
- The resin pellets are heated and cooled in a mold that can be rotated in 3 dimensions. The rotation evenly distributes the plastic along the walls of the mold
- Extrusion
- Bioplastics
- Naturally occurring polymers such as starches, cellulose, soy protein, vegetable oil, triglycerides, and bacterial polyesters, can be extracted from crops and bacterias
- Furthermore, plants and microorganisms can produce substances like lactic acid, which can be polymerized into bioplastics
- Fermentation
- Bacteria or other microorganisms mass-produce the bio-polymers in bioreactors /fermentation tanks
- The bio-polymers are extracted from the bioreactors and chemically processed into plastics
- Bacteria or other microorganisms mass-produce the bio-polymers in bioreactors /fermentation tanks
- Bioplastics have the advantage of being produced from renewable resources rather than non-renewable resources
- Furthermore, bioplastics are biodegradable - they can break down in the environment, which means its a very important industry
- Naturally occurring polymers such as starches, cellulose, soy protein, vegetable oil, triglycerides, and bacterial polyesters, can be extracted from crops and bacterias
- Recycling
- Once collected, plastics go through a variety of steps
- Inspection to weed out contaminants and inappropriate types of plastics
- Shredding and washing
- Separation based on density
- Drying
- Melting
- Draining through fine screens to remove more contaminants
- Cooling and shedding into pellets
- Selling back to plastic companies
- Cooling and shedding into pellets
- Draining through fine screens to remove more contaminants
- Melting
- Drying
- Separation based on density
- Shredding and washing
- What is a plastic?
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