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picture1_Bulk Polymerization Example 91910 | Bulk Polymerization Of Styrene


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File: Bulk Polymerization Example 91910 | Bulk Polymerization Of Styrene
bulk polymerization of styrene ingredients 1 4gm styrene l 2 35mg aibn s 3 toluene l to dissolve the polystyrene 30ml 4 propanol l to precipitate the polystyrene 100ml 5 ...

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                   Bulk polymerization of Styrene 
         
        Ingredients: 
         1.  4gm Styrene (l) 
         2.  35mg AIBN (s) 
         3.  Toluene (l) (to dissolve the polystyrene) ~30ml 
         4.  Propanol (l) ( to precipitate the polystyrene ) ~ 100ml 
         5.  Hot plate and a water bath 
         
        Procedure: 
         1.  Place water in the bath and heat to ~80°C (You need enough water in bath to 
           submerge the contents of the test tube in hot water) 
         2.  Add 4gm of styrene in a test tube. 
         3.  Add 35 mg (excess) of AIBN to the beaker. Stir to dissolve the AIBN in styrene 
           with a glass rod. AIBN is used to initiate the styrene on heating above 60 C. (The 
           excess AIBN reacts with the stabilizer BHT which is a free radical scavenger 
           present in styrene.  You can also distill the styrene to remove BHT for a cleaner 
           reaction.) 
         4.  Place the test tube in the hot water bath for about 20-25 mins.  
         5.  You will notice the solution getting thicker indicating the formation of 
           polystyrene. 
         6.  Remove the beaker from the bath and dip the beaker in cold water for a few 
           minutes (to quench). It will be ideal to use ice for quenching, but cold water from 
           tap works. 
         7.  The quenching process will either solidify or really thicken the polystyrene. 
         8.  Add toluene to the test tube and transfer to a beaker to add the remaining toluene 
           to a total of 30 ml to dissolve the polystyrene. Stir well.  Toluene is a good 
           solvent for the monomer and polymer. 
         9.  Once the polystyrene is dissolved, add excess propanol while stirring.  Propanol is 
           a non-solvent for styrene but has some miscibility with monomer and toluene.  
           You will immediately notice the white precipitate of polystyrene. Continue 
           stirring at this time. 
         10. After stirring let the contents in the beaker settle down for a couple of minutes 
           and add more propanol. You will see the polystyrene (white chunk) form in the 
           beaker. Decant the toluene/propanol solution and wash the polystyrene precipitate 
           with toluene a few more times.  The polystyrene can be removed and dried on 
           filter paper. 
          
         Precautions: 
         1.  Styrene vapors are potentially carcinogenic (still under debate, check Wiki page 
           of Styrene). You may cover the beaker while heating to reduce the release of 
           styrene vapors.  For small amounts this procedure can be conducted with no hood 
           as long as the room is relatively well ventilated. 
         2.  AIBN should be handled with gloves and avoid contact with AIBN, dust or  
           vapors. 
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...Bulk polymerization of styrene ingredients gm l mg aibn s toluene to dissolve the polystyrene ml propanol precipitate hot plate and a water bath procedure place in heat c you need enough submerge contents test tube add excess beaker stir with glass rod is used initiate on heating above reacts stabilizer bht which free radical scavenger present can also distill remove for cleaner reaction about mins will notice solution getting thicker indicating formation from dip cold few minutes quench it be ideal use ice quenching but tap works process either solidify or really thicken transfer remaining total well good solvent monomer polymer once dissolved while stirring non has some miscibility immediately white continue at this time after let settle down couple more see chunk form decant wash times removed dried filter paper precautions vapors are potentially carcinogenic still under debate check wiki page may cover reduce release small amounts conducted no hood as long room relatively ventilate...

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