m (J.M.Pearce moved page PET drying protocol:MOST to PET preparation protocol:MOST: author wants it)
(Conversion to Drying + Shredding+ Cleaning)
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'''THIS METHOD IS CURRENTLY  A WORK IN PROGRESS'''
'''THIS METHOD IS CURRENTLY  A WORK IN PROGRESS'''


Here is outlined the method to dry shredded PET in a convection oven at the MOST lab at Michigan Technological University. PET needs to be dried prior to extrusion in a [[Recyclebot]] as otherwise it will undergo rapid hyrdolyzation at high temperatures, and reduce the molecular mass. For more information please see the [[PET Extrusion]] literature review.
Here is outlined the method to shred, clean and dry PET at the MOST lab at Michigan Technological University. For more information on PET mechanisms please see the [[PET Extrusion]] literature review.


==Equipment==
==Shredding and Cleaning==
Any PET bottles or containers which are to be to be recycled need to be ground up into smaller pieces first. This is to speed up the drying process, and also, to fit the plastic into the RecycleBot hopper.
 
===Shredding and Cleaning: Equipment===
*Shredder
*Oil-based cleaner to remove glue, see step 2. (NO WD40)
*Scissors or shears
 
===Shredding and Cleaning: Procedure===
# Peal any labels and/or different colored plastics off of the bottle.
# Remove any glue from the wrappings off using your cleaner. MOST used => TESTING IN PROGRESS.
# Rinse out your container, and dry, to remove any leftover beverages.
# Cut apart bottles and containers to fit into your shredder
# Shred the PET chunks. MOST has used a "Chipper Joe", green woodchipper and a disk shredder, from Staples.
# Collect the chunks and store somewhere cool and dry until the drying step, just as a preventative measure to moisture buidup
 
==Drying==
PET needs to be dried prior to extrusion in a [[Recyclebot]] as otherwise it will undergo rapid hyrdolyzation at high temperatures, and reduce the molecular mass.
 
===Drying: Equipment===
*Convection Drying Oven (Any oven will generally work, ovens at home run off the same convection principles of heating and moving air. If using a home oven, be careful of temperatures, and be aware that there could potentially be burning plastic inside of it, if proper precautions are not taken)
*Convection Drying Oven (Any oven will generally work, ovens at home run off the same convection principles of heating and moving air. If using a home oven, be careful of temperatures, and be aware that there could potentially be burning plastic inside of it, if proper precautions are not taken)
*Shredded PET
*Shredded PET
*Drying tray (Any metal tray to hold the PET shreds)
*Drying tray (Any metal tray to hold the PET shreds)


==Procedure==
===Drying: Procedure===
# Turn on the oven
# Turn on the oven
# Evenly distribute the shredded PET in the drying tray. This exposes more surface area to enhance evaporation speed.
# Evenly distribute the shredded PET in the drying tray. This exposes more surface area to enhance evaporation speed.

Revision as of 20:15, 21 October 2014

THIS METHOD IS CURRENTLY A WORK IN PROGRESS

Here is outlined the method to shred, clean and dry PET at the MOST lab at Michigan Technological University. For more information on PET mechanisms please see the PET Extrusion literature review.

Shredding and Cleaning

Any PET bottles or containers which are to be to be recycled need to be ground up into smaller pieces first. This is to speed up the drying process, and also, to fit the plastic into the RecycleBot hopper.

Shredding and Cleaning: Equipment

  • Shredder
  • Oil-based cleaner to remove glue, see step 2. (NO WD40)
  • Scissors or shears

Shredding and Cleaning: Procedure

  1. Peal any labels and/or different colored plastics off of the bottle.
  2. Remove any glue from the wrappings off using your cleaner. MOST used => TESTING IN PROGRESS.
  3. Rinse out your container, and dry, to remove any leftover beverages.
  4. Cut apart bottles and containers to fit into your shredder
  5. Shred the PET chunks. MOST has used a "Chipper Joe", green woodchipper and a disk shredder, from Staples.
  6. Collect the chunks and store somewhere cool and dry until the drying step, just as a preventative measure to moisture buidup

Drying

PET needs to be dried prior to extrusion in a Recyclebot as otherwise it will undergo rapid hyrdolyzation at high temperatures, and reduce the molecular mass.

Drying: Equipment

  • Convection Drying Oven (Any oven will generally work, ovens at home run off the same convection principles of heating and moving air. If using a home oven, be careful of temperatures, and be aware that there could potentially be burning plastic inside of it, if proper precautions are not taken)
  • Shredded PET
  • Drying tray (Any metal tray to hold the PET shreds)

Drying: Procedure

  1. Turn on the oven
  2. Evenly distribute the shredded PET in the drying tray. This exposes more surface area to enhance evaporation speed.
  3. Open the oven by firmly opening the door. It may take a quick jerk, but be careful not to topple it.
  4. Place the tray inide the oven.
  5. Close the oven door, firmly.
  6. Set the temperature on your oven to a value as shown by the table below. This table is a work in progress, please feel free to contribute and check!
  7. Wait for an amount of time also shown in the table above.
  8. Switch off the oven then carefully open the door after letting it cool for a few minutes.
  9. Quickly place the PET in an airtight container, such as inside two (2) layers of plastic bags that are twisted and tied shut. As long as the PET is not allowed to reabsorb water from the air, any arrangement will work.
  10. Store PET in a cool dry place until it is to be used. One excellent method is to place the dry PET inside a bag, which also has dessicant. This further dries the plastic, and will remove any moisture that may have accrued whilst handling it.

Temperature and Time Table

Important temperatures to be mindful of: 260°C is the melting point at 70-80°C is the glass transition temperature. Because "wet" plastic is being dried, it will likely begin to degrade far below the melting point. For a plastic, the melting point will not signfy much, as the plastic molecules will break apart before the overall material ever reaches that temperature.

1 Hour 2 Hours 3 Hours 4 Hours 5 Hours 6 Hours
82°C

Slightly above Tg

No Change No change
100°C
125°C
150°C
175°C
200°C
225°C
250°C
275°C
300°C
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