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Some Basic Chemistry: Single and Double Bonds

H. –. –. –. C. C. H. C. H. CH 4. –. H. H. H. –. –. C. C. –. –. –. H. C. C. H. C 2 H 6. –. –. H. H. H. H. –. –. –. C. C. C. C. –. C 2 H 4. –. –. H. H. Some Basic Chemistry: Single and Double Bonds. Some Basic Chemistry: Functional Groups. CH 2 =CH 2.

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Some Basic Chemistry: Single and Double Bonds

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  1. H – – – C C H C H CH4 – H H H – – C C – – – H C C H C2H6 – – H H H H – – – C C C C – C2H4 – – H H Some Basic Chemistry: Single and Double Bonds

  2. Some Basic Chemistry: Functional Groups CH2=CH2 Ethylene O O = = + R–OH R–C–OH R–C–O–R Alcohol Carboxylic Acid Ester O O = = R–NH2 + R–C–OH R–C–NH–R Amine Carboxylic Acid Amide Functional groups - small groups of atoms held together in specific arrangement by covalent bonds Responsible for principal chemical properties of molecule

  3. O Ester linkage O Ethyl Acetate Some Basic Chemistry: Condensation Reactions Ethyl Alcohol or Ethanol reversible reaction CH3 - C - OH + CH3 - CH2 - OH CH3 - C - O - CH2 - CH3 + H2O Acetic Acid

  4. Now…to make a Polymer These molecules are monofunctional: + To make linear chains need bifunctional molecules: Except, reaction goes step-wise

  5. Polyester - step 1 O O O O Monomers HO - C - (CH2)n - C - OH + HO - (CH2)m - OH HO - C - (CH2)n - C - O - (CH2)m - OH + H2O Dimer

  6. O O HO - C - (CH2)n - C - O - (CH2)m - OH + HO - C - (CH2)n - C - OH O O O O Trimer - H2O HO - C - (CH2)n - C - O - (CH2)m - O - C - (CH2)n - C - OH O O M3 + M2 M5 M1 + M1 M2 M2 + M1 M3 M2 + M2 M4 M3 + M1 M4 M5 + M1 M6 M4 + M1 M5 Etc. Polyester Reacting diacid & dialcohol give polyester

  7. H2N - (CH2)6 - NH2 + HO - C - (CH2)4 - C - OH Hexamethylene Diamine Adipic Acid O O O O H2N - (CH2)6 - N - C - (CH2)4 - C - OH + H2O Amide Group H Nylons

  8. Nylon 6,6 O O - N - (CH2)6 - N - C - (CH2)4 - C - n 6 6 H H “I am making the announcement of a brand new chemical textile fiber ---derivable from coal, air and water -- and characterized by extreme toughness and strength --” Charles Stine V.P. for research, Du Pont, 1938

  9. Nylon “I am making the announcement of a brand new chemical textile fiber ---derivable from coal, air and water -- and characterized by extreme toughness and strength --” Charles Stine V.P. for research, Du Pont, 1938

  10. Nylon May 15 1940 - “Nylon Day” Four million pairs go on sale throughout US Supply exhausted in 4 days.

  11. Nylon Parachute WWII

  12. Post WWII stocking sale, San Francisco.

  13. O = C = N - (CH2)6 - N = C = O + HO - (CH2)2 - OH O Hexamethylene Diisocyanate Ethylene Glycol O = C = N - (CH2)6 - N - C - O - (CH2)2 - OH Urethane Linkage H Polyurethanes Reaction does not involve splitting out of a small molecule usw.

  14. Branched - short branches Linear & branched polymers ex: polyethylene Linear

  15. CH2 - CH2 ~~~CH2 - CH CH2 H .CH2 Formation of short chain branches in polyethylene CH2 - CH2 ~~~CH2 - CH CH2 . CH2H CH2 = CH2 C4H9 - ~~~CH2 - CH - CH2 - CH2. C4H9 - ~~~CH2 - CH - CH2 - CH2- CH2 - CH2. CH2 = CH2 Linear & branched polymers ex: polyethylene

  16. Low density polyethylene (LDPE) (short branches)

  17. Other types of branching short long star Branching suppresses or prevents chain movement & "crystallization" in polymers

  18. Branching Another way to make chains branch * * Use multifunctional (f>2) monomers * OH + CH O 2 OH OH OH CH CH CH 2 2 2 OH CH CH CH 2 2 2 OH OH OH CH 2 OH

  19. The phenol + formaldehyde rxn

  20. Network formation Further reaction under heat & pressure builds up densely cross-linked network. This is Bakelite, a thermosettingpolymer. Once reaction is complete, material cannot be reheated and/or reformed Bakelite

  21. Bakelite - Material of a Thousand Uses Bakelite telephone Clear Bakelite items Phenolic resin/celluloidclock Bakelite radio Bakelite microphone Bakelite camera

  22. Crosslinking Take linear polymer chains & link using covalent bonds

  23. - CH2 CH2 - CH2 CH2 - CH2 CH2 - - - - - - - C = C C = C C = C - - - - - - CH3 H CH3 H CH3 H Crosslinking Ex: rxn of natural rubber or poly(isoprene) with sulfur - interconnects the chains by reacting with the double bonds (vulcanization)

  24. Crosslinking

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