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Condensation polymers

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. Nylon experiment. POLYAMIDES - NYLON-6,6.

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Condensation polymers

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  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 Reagentshexanedioic acid hexane-1,6-diamine HOOC(CH2)4COOH H2N(CH2)6NH2 Mechanismaddition-elimination Eliminatedwater Equationn HOOC(CH2)4COOH + n H2N(CH2)6NH2 ——> -[NH(CH2)6NHOC(CH2)4CO] n- + n H2O Repeatunit—[-NH(CH2)6NHOC(CH2)4CO-]n— ProductNylon-6,6 two repeating units, each with 6 carbon atoms

  5. PEPTIDES Reagentsamino acids EquationH2NCCH2COOH + H2NC(CH3)COOH ——> H2NCCH2CONHHC(CH3)COOH + H2O 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 joined dipeptide 3 amino acids joined tripeptide many amino acids joined polypeptide a dipeptide

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

  7. Terylene

  8. POLYESTERS - TERYLENE Reagentsterephthalic acidHOOC-C6H4-COOH ethane-1,2-diolHOCH2CH2OH Reactionesterification Eliminatedwater Equationn HOCH2CH2OH + n HOOC-C6H4-COOH ——> -[OCH2CH2OOC(C6H4)CO] n- + n H2O

  9. POLYESTERS - TERYLENE Reagentsterephthalic acidHOOC-C6H4-COOH ethane-1,2-diolHOCH2CH2OH Reactionesterification Eliminatedwater Equationn HOCH2CH2OH + n HOOC-C6H4-COOH ——> -[OCH2CH2OOC(C6H4)CO] n- + n H2O Repeatunit— [-OCH2CH2OOC(C6H4)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) Reagent 2-hydroxypropanoic acid (lactic acid) CH3CH(OH)COOH CARBOXYLIC ACID END ALCOHOL END

  11. POLYESTERS – POLY(LACTIC ACID) Reagent 2-hydroxypropanoic acid (lactic acid) CH3CH(OH)COOH Reactionesterification Eliminatedwater Equationn CH3CH(OH)COOH —> −[-OCH(CH3)CO-]n − + n H2O Productpoly(lactic acid) Repeatunit— [-OCH(CH3)CO-] — CARBOXYLIC ACID END ALCOHOL END

  12. POLYESTERS – POLY(LACTIC ACID) Reagent 2-hydroxypropanoic acid (lactic acid) CH3CH(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) Uses waste sacks and packaging disposable eating utensils internal stitches CARBOXYLIC ACID END ALCOHOL END

  13. POLYAMIDES – KEVLAR Reagents benzene-1,4-diamine benzene-1,4-dicarboxylic acid Repeatunit Propertiescontains an amide link Uses body armour

  14. POLYAMIDES - NYLON-6,6 Reagentshexanedioic acid hexane-1,6-diamine HOOC(CH2)4COOH H2N(CH2)6NH2 Mechanismaddition-elimination Eliminatedwater Equationn HOOC(CH2)4COOH + n H2N(CH2)6NH2 ——> -[NH(CH2)6NHOC(CH2)4CO] n- + n H2O

  15. Hydrolysis of polyester

  16. 4.9 Exercise 2

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