1. Condensation polymers L.O.:  Understand how condensation polymers may be formed.  know the linkage of the repeating units of polyesters (e.g.Terylene) and polyamides (e.g. nylon 6,6 and Kevlar).  Explain why polyester and polyamides are biodegradable.

2. Nylon experiment

3. POLYAMIDES - NYLON-6,6 Propertiescontains a peptide (or amide) link can be broken down by hydrolysis the C-N bond breaks behave as amides biodegradable can be spun into fibres for strength Usesfibres and ropes

4. POLYAMIDES - NYLON-6,6 Reagents hexanedioic acidhexane-1,6-diamine HOOC(CH 2 ) 4 COOH H 2 N(CH 2 ) 6 NH 2 Mechanismaddition-elimination Eliminatedwater Equation n HOOC(CH 2 ) 4 COOH + n H 2 N(CH 2 ) 6 NH 2 ——> -[NH(CH 2 ) 6 NHOC(CH 2 ) 4 CO] n - + n H 2 O Repeat unit—[-NH(CH 2 ) 6 NHOC(CH 2 ) 4 CO-] n — ProductNylon-6,6two repeating units, each with 6 carbon atoms

5. PEPTIDES Reagentsamino acids Equation H 2 NCCH 2 COOH + H 2 NC(CH 3 )COOH ——> H 2 NCCH 2 CONHHC(CH 3 )COOH + H 2 O Productpeptide (the above shows the formation of a dipeptide) Eliminatedwater Mechanismaddition-elimination Amino acids join together via an amide or peptide link 2 amino acids joineddipeptide 3 amino acids joinedtripeptide many amino acids joinedpolypeptide a dipeptide

6. CONDENSATION POLYMERS monomers join up the with expulsion of small molecules not all the original atoms are present in the polymer Examplespolyamides(nylon)(kevlar) polyesters(terylene) (polylactic acid) peptides starch Synthesis reactions between diprotic carboxylic acids and diols diprotic carboxylic acids and diamines amino acids ESTER LINKAMIDE LINK

7. Terylene

8. POLYESTERS - TERYLENE Reagentsterephthalic acidHOOC-C 6 H 4 -COOH ethane-1,2-diolHOCH 2 CH 2 OH Reactionesterification Eliminatedwater Equation n HOCH 2 CH 2 OH + n HOOC-C 6 H 4 -COOH ——> -[OCH 2 CH 2 OOC(C 6 H 4 )CO] n - + n H 2 O

9. POLYESTERS - TERYLENE Reagentsterephthalic acidHOOC-C 6 H 4 -COOH ethane-1,2-diolHOCH 2 CH 2 OH Reactionesterification Eliminatedwater Equation n HOCH 2 CH 2 OH + n HOOC-C 6 H 4 -COOH ——> -[OCH 2 CH 2 OOC(C 6 H 4 )CO] n - + n H 2 O Repeat unit— [-OCH 2 CH 2 OOC(C 6 H 4 )CO-] n — Productpoly(ethylene terephthalate)‘Terylene’, ‘Dacron’ Propertiescontains an ester link can be broken down by hydrolysis the C-O bond breaks behaves as an ester biodegradable Usesfabricsan ester link

10. POLYESTERS – POLY(LACTIC ACID) Reagent2-hydroxypropanoic acid (lactic acid)CH 3 CH(OH)COOH CARBOXYLIC ACID END ALCOHOL END

11. POLYESTERS – POLY(LACTIC ACID) Reagent2-hydroxypropanoic acid (lactic acid)CH 3 CH(OH)COOH Reactionesterification Eliminatedwater Equation n CH 3 CH(OH)COOH —> −[-OCH(CH 3 )CO-] n − + n H 2 O Productpoly(lactic acid) Repeat unit— [-OCH(CH 3 )CO-] — CARBOXYLIC ACID END ALCOHOL END

12. POLYESTERS – POLY(LACTIC ACID) Reagent2-hydroxypropanoic acid (lactic acid)CH 3 CH(OH)COOH Productpoly(lactic acid) Propertiescontains an ester link can be broken down by hydrolysis the C-O bond breaks behaves as an ester (hydrolysed at the ester link) biodegradable photobiodegradable (C=O absorbs radiation) Useswaste sacks and packaging disposable eating utensils internal stitches CARBOXYLIC ACID END ALCOHOL END

13. POLYAMIDES – KEVLAR Reagentsbenzene-1,4-diamine benzene-1,4-dicarboxylic acid Repeat unit Propertiescontains an amide link Usesbody armour

14. POLYAMIDES - NYLON-6,6 Reagents hexanedioic acidhexane-1,6-diamine HOOC(CH 2 ) 4 COOH H 2 N(CH 2 ) 6 NH 2 Mechanismaddition-elimination Eliminatedwater Equation n HOOC(CH 2 ) 4 COOH + n H 2 N(CH 2 ) 6 NH 2 ——> -[NH(CH 2 ) 6 NHOC(CH 2 ) 4 CO] n - + n H 2 O

15. Hydrolysis of polyester

16. 4.9 Exercise 2