POLYMERS A guide for GCSE students KNOCKHARDY PUBLISHING

POLYMERS A guide for GCSE students KNOCKHARDY PUBLISHING 2010 SPECIFICATIONS

POLYMERS INTRODUCTION This Powerpoint show is one of several produced to help students understand selected GCSE Chemistry topics. It is based on the requirements of the AQA specification but is suitable for other examination boards. Individual students may use the material at home for revision purposes and it can also prove useful for classroom teaching with an interactive white board. Accompanying notes on this, and the full range of AS and A 2 Chemistry topics, are available from the KNOCKHARDY WEBSITE at. . . www. knockhardy. org. uk All diagrams, photographs and any animations in this Powerpoint are original and created by Jonathan Hopton. Permission must be obtained for their use in any work that is distributed for financial gain.

POLYMERS CONTENTS • What is polymerisation? • Types of polymerisation • Addition polymerisation of ethene • Other polymerisation examples • Sources of monomers • Disposal of polymers • Questions For more detailed information on fractional distillation, cracking and the properties of hydrocarbons such as alkanes and alkenes, see the appropriate Powerpoint on the Knockhardy GCSE site. www. knockhardy. org. uk/gcse. htm

WHAT IS POLYMERISATION?

POLYMERISATION A process in which small molecules called monomers join together into large molecules consisting of repeating units.

POLYMERISATION A process in which small molecules called monomers join together into large molecules consisting of repeating units. There are two basic types

POLYMERISATION 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 examples poly(ethene), polystyrene, pvc, ptfe

POLYMERISATION 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 examples CONDENSATION poly(ethene), polystyrene, pvc, ptfe monomers join up the with expulsion of small molecules not all the original atoms are present in the polymer examples nylon, polyesters, pva

POLYMERISATION 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 examples CONDENSATION poly(ethene), polystyrene, pvc, ptfe monomers join up the with expulsion of small molecules not all the original atoms are present in the polymer examples nylon, polyesters, pva ALKENES UNDERGO ADDITION POLYMERISATION

POLYMERISATION • during polymerisation, alkenes undergo an addition reaction • all the atoms in the original alkenes are used to form the polymer • long hydrocarbon chains are formed

POLYMERISATION • during polymerisation, alkenes undergo an addition reaction • all the atoms in the original alkenes are used to form the polymer • long hydrocarbon chains are formed • the diagram shows… the original monomer and the repeating unit in the polymer ethene MONOMER poly(ethene) POLYMER

POLYMERISATION • during polymerisation, alkenes undergo an addition reaction • all the atoms in the original alkenes are used to form the polymer • long hydrocarbon chains are formed • the diagram shows… the original monomer and the repeating unit in the polymer n represents a large number ethene MONOMER poly(ethene) POLYMER the number of repeating units is the same as the number of original molecules

POLYMERISATION The animation shows the monomers turning into the polymer

OTHER POLYMERISATION REACTIONS ETHENE PROPENE CHLOROETHENE POLY(ETHENE) POLY(PROPENE) POLY(CHLOROETHENE) POLYVINYLCHLORIDE TETRAFLUOROETHENE PVC POLY(TETRAFLUOROETHENE) PTFE “Teflon”

SOURCES OF MONOMERS

SOURCES OF MONOMERS FROM CRUDE OIL

SOURCES OF MONOMERS FROM CRUDE OIL IS FRACTIONALLY DISTILLED HEAVIER HYDROCARBON FRACTIONS ARE LESS USEFUL

SOURCES OF MONOMERS FROM CRUDE OIL IS FRACTIONALLY DISTILLED HEAVIER HYDROCARBON FRACTIONS ARE LESS USEFUL THEIR MOLECULES ARE BROKEN DOWN INTO SMALLER ONES THIS PROCESS IS KNOWN AS CRACKING

SOURCES OF MONOMERS FROM CRUDE OIL IS FRACTIONALLY DISTILLED HEAVIER HYDROCARBON FRACTIONS ARE LESS USEFUL THEIR MOLECULES ARE BROKEN DOWN INTO SMALLER ONES THIS PROCESS IS KNOWN AS CRACKING ETHENE (an alkene)

SOURCES OF MONOMERS FROM CRUDE OIL IS FRACTIONALLY DISTILLED HEAVIER HYDROCARBON FRACTIONS ARE LESS USEFUL THEIR MOLECULES ARE BROKEN DOWN INTO SMALLER ONES THIS PROCESS IS KNOWN AS CRACKING ETHENE (an alkene) ALKENES ARE AN IMPORTANT PRODUCT OF CRACKING ETHENE (C 2 H 4) IS THE MOST IMPORTANT ALKENE

PROBLEMS WITH POLYMERS

PROBLEMS WITH POLYMERS Although polymers derived from alkenes are invaluable to modern society, their disposal creates widespread problems.

PROBLEMS WITH POLYMERS Although polymers derived from alkenes are invaluable to modern society, their disposal creates widespread problems. • they are unreactive to most chemicals • they are unreactive to bacteria (non-biodegradable) • if they are just discarded they add to the landfill problem

PROBLEMS WITH POLYMERS Although polymers derived from alkenes are invaluable to modern society, their disposal creates widespread problems. • they are unreactive to most chemicals • they are unreactive to bacteria (non-biodegradable) • if they are just discarded they add to the landfill problem OPTIONS

PROBLEMS WITH POLYMERS Although polymers derived from alkenes are invaluable to modern society, their disposal creates widespread problems. • they are unreactive to most chemicals • they are unreactive to bacteria (non-biodegradable) • if they are just discarded they add to the landfill problem OPTIONS recycling high cost of collection and re-processing incinerate saves on landfill sites and produces energy produces toxic fumes Plastic bags are being made from polymers and cornstarch so that they break down more easily but…

POLYMERISATION OF ALKENES QUESTIONS

POLYMERISATION OF ALKENES CAN YOU SPOT THE ORIGINAL ALKENE MONOMER?

For more detailed information on FRACTIONAL DISTILLATION AND CRACKING, please see the appropriate Powerpoint on the Knockhardy GCSE site. www. knockhardy. org. uk/gcse. htm