Addition polymers  Draw the repeating unit of addition polymers from monomer structures and vice versa,

General A process in which small molecules called monomers join together into large molecules consisting of repeating units. There are two basic types ADDITION all the atoms in the monomer are used to form the polymer CONDENSATION monomers join up the with expulsion of small molecules not all the original atoms are present in the polymer POLYMERISATION

all the atoms in the monomer are used to form the polymer occurs with alkenes mechanism can be free radical or ionic ADDITION POLYMERISATION

Role-play

POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are used to form the polymer long hydrocarbon chains are formed ADDITION POLYMERISATION

POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are used to form the polymer long hydrocarbon chains are formed ADDITION POLYMERISATION The equation shows the original monomer and the repeating unit in the polymer ethene poly(ethene) MONOMER POLYMER n represents a large number

POLYMERISATION OF ALKENES ADDITION POLYMERISATION The equation shows the original monomer and the repeating unit in the polymer ethene poly(ethene) MONOMER POLYMER n represents a large number

Is it biodegradable? Why

Discuss: o Benefits of recycling. o Disadvantages of recycling.

POLYMERISATION OF ALKENES ETHENE EXAMPLES OF ADDITION POLYMERISATION PROPENE TETRAFLUOROETHENE CHLOROETHENE POLY(ETHENE) POLY(PROPENE) POLY(CHLOROETHENE) POLYVINYLCHLORIDE PVC POLY(TETRAFLUOROETHENE) PTFE “Teflon”

POLYMERISATION OF ALKENES SPOTTING THE MONOMER

POLYMERISATION OF ALKENES SPOTTING THE MONOMER

POLYMERISATION OF PROPENE - ANIMATION AN EXAMPLE OF ADDITION POLYMERISATION

9.1 Exercise 1 Exercise 2

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

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

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

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

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

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

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

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

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

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

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

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

HYDROLYSIS OF PEPTIDES Hydrolysis + H 2 O ——> HOOCCH 2 NH 2 + HOOCCH(CH 3 )NH 2 The acid and amine groups remain as they are Hydrolysis is much quicker if acidic or alkaline conditions are used. However, there is a slight variation in products.

HYDROLYSIS OF PEPTIDES Hydrolysis + H 2 O ——> HOOCCH 2 NH 2 + HOOCCH(CH 3 )NH 2 The acid and amine groups remain as they are Acid hydrolysis + 2HC l ——> HOOCCH 2 NH 3 + C l ¯ + HOOCCH(CH 3 )NH 3 + C l ¯ The acid groups remain as they are and the amine groups are protonated

HYDROLYSIS OF PEPTIDES Hydrolysis + H 2 O ——> HOOCCH 2 NH 2 + HOOCCH(CH 3 )NH 2 The acid and amine groups remain as they are Acid hydrolysis + 2HC l ——> HOOCCH 2 NH 3 + C l ¯ + HOOCCH(CH 3 )NH 3 + C l ¯ The acid groups remain as they are and the amine groups are protonated Base (alkaline) hydrolysis + 2NaOH ——> Na+ ¯OOCCH 2 NH 2 + Na+ ¯OOCCH(CH 3 )NH 2 The acid groups become sodium salts and the amine groups remain as they are

HYDROLYSIS OF PEPTIDES Hydrolysis + H 2 O ——> HOOCCH 2 NH 2 + HOOCCH(CH 3 )NH 2 The acid and amine groups remain as they are Acid hydrolysis + 2HC l ——> HOOCCH 2 NH 3 + C l ¯ + HOOCCH(CH 3 )NH 3 + C l ¯ The acid groups remain as they are and the amine groups are protonated Base (alkaline) hydrolysis + 2NaOH ——> Na+ ¯OOCCH 2 NH 2 + Na+ ¯OOCCH(CH 3 )NH 2 The acid groups become sodium salts and the amine groups remain as they are

PROTEINS polypeptides with large relative molecular masses (>10000) chains can be lined up with each other the C=O and N-H bonds are polar due to a difference in electronegativity hydrogen bonding exists between chains dotted lines represent hydrogen bonding

THE CHEMISTRY OF POLYMERS THE END © 2009 JONATHAN HOPTON & KNOCKHARDY PUBLISHING