华东师大二附中校本课chemistryaroundus

1、Chemistry Around UsPlasticsPlastics are used for thousands of different objectsPlastics are used for thousands of different objects The most common types of plasticsThe most common types of plasticsPolythene (PE) 聚乙烯The most common types of plasticsPolypropene (PP) 聚丙烯The most common types of plasti

2、csPolyvinyl chloride (PVC) 聚氯乙烯The most common types of plasticsPolystyrene (PS) 聚苯乙烯The most common types of plasticspolyterafluoroethene (PTFE) or teflon 聚四氟乙烯The most common types of plasticsNylon 尼龙The most common types of plasticsUrea-methanal 脲甲醛The most common types of plasticsPerspex 有机玻璃The

3、 most common types of plasticsMalamine 三聚氰酰胺1. The classification of plasticsTwo simple tests for classification:The first test - heating a sample of the plastics in boiling water or in the oil.The second test - heating a sample of the plastics strongly.Two simple tests for classificationTest 1Test

4、2The wall socket chars and cracks when heated stronglyPlastics can be classified into two main types according to their thermal behaviorThermoplastics (热塑性塑料)Examples: polythene (PE) 聚乙烯 polypropene (PP) 聚丙烯 polyvinyl chloride (PVC) 聚氯乙烯 polystyrene (PS) 聚苯乙烯 perspex 有机玻璃 nylon 尼龙 Thermosetting plas

5、tics （热固性塑料） Examples: urea-methanal 脲甲醛 melamine 三聚氰酰胺- They are flexible. They soften and melt on heating and re-harden on cooling.- They are hard and rigid. They do not soften or melt but decompose on strong heating.bakelite 电木2. The formation of plasticsnmonomerpolymerethenepolyethenevinyl chlor

6、idepolyvinyl chloriden2. The formation of plasticsPolymer （聚合物）- very long molecules（分子）Monomer （单体）- smaller moleculesPolymerization （聚合反应）- the joining-up processPolymerization can be classified into two main typesAddition polymerization(加聚反应)Condensation polymerization（缩聚反应）2. The formation of pl

7、asticsMost of plastics are made by addition polymerization （加聚反应）加聚反应） of Alkenes and Substituted Alkenes ( (烯烃烯烃) ) ( (取代烯烃取代烯烃) ) Polythene (PE) 聚乙烯Polyvinyl chloride (PVC) 聚氯乙烯Polypropene (PP) 聚丙烯Polystyrene (PS) 聚苯乙烯Polyterafluoroethene (PTFE) 聚四氟乙烯Perspex有机玻璃2. The formation of plasticsSome of

8、thermoplastics and all of thermosetting plastics are made by condensation polymerization （缩聚反应）Nylon 尼龙Urea-methanal 脲甲醛Making nylon in the laboratory2. The formation of plastics2. The formation of plasticsLaboratory preparation of urea-methanal3. Some useful properties of Plasticseasily shaped reac

9、tivewaterproofgood insulatorseasily colored lighthardly shapedunreactivegood conductorshardly coloredheavyflexible strongtoughSome useful properties of PlasticsPlastics are easily shapedSome useful properties of PlasticsPlastics are unreactiveSome useful properties of PlasticsPlastics are flexiblePl

10、astics are good insulatorsSome useful properties of PlasticsPlastics are easily coloredSome useful properties of PlasticsSome useful properties of PlasticsPlastics are lightSome useful properties of PlasticsPlastics are waterproofSome useful properties of PlasticsPlastics are quite strongSome useful

11、 properties of PlasticsPlastics are toughThis is not the useful property of plastics!Comparing plastic water pipe with metal water pipe just as strongmore resistant to corrosioneasier to make, bend or cutcheaperPlastic water pipeMetal water pipe4. Problems with Plastics4. Problems with PlasticsWays

12、of waste disposalBy incinerationIncinerating plastics as a methods of disposal is not only wasteful but dangerous!Air pollutionWays of waste disposalBy landfillsWaste of land and spaceMost of plastics are non-biodegradable （不可生物降解） The disposal of waste into landfill takes up a lot of space and land

13、Plastic wastes are disposed into the seaDeath of many sea animalsThe plastic wastes not only pollute the sea, but kill many sea animals such as sea birds and fishes.A sea bird gets tangled in plastic objectsLarge amount of plastic wastes disposed to the sea.Large amount of plastic wastes are thrown

14、awayWaste of petroleumAll plastics are made from petroleum.It would be worth saving if it is possibleWhat is the problem with plastics?Disposal of plastic wasteWhat should we do?Reusing plasticsEmpty margarine box can be used to hold stationerySoft drink bottle can beused to fill water Plastic bag c

15、an beused repeatedlyRecycled plasticCollection points like this one can help to recycle plasticsRecycling plasticsLabels like this help to identify the plastic for recycling Different rubbish bins for collection different types of plasticsProducing more environmentally friendly productsBiodegradable

16、 plasticPhotodegradable plasticReplacing plastics with some other materialsReducing the use of plasticsThe edible cling wrap has been produced 据报道，可食用保鲜膜在美问世。Improving incinerating plastic waste to produce electricity据报道，浦东新建的垃圾焚烧发电厂为缓解每年夏季的用电高峰出了力。Ways of recycling1. They can be used as raw materia

17、ls to make cheap building materials.2. They can be softened by heat and passed through rollers to make plastic sheets.3. Specific plastics can be recycled for reuse either as the plastic article itself or as a source of that plastic.4. The plastic can be used as a raw material to produce more monome

18、rs.Ways of recyclingBlack rubbish bagsProblems with recycling The recycling of plastics from ordinary domestic waste is very difficult.Plastic waste is a mixture of many different chemical compounds.There is an increasing tendency to use a mixture of plastics in the same article.65% polythene and po

19、lypropene15% polystyrene10% PVC5% PET5% other plastics and mixtures of plasticsProblems with recyclingThis video tape is made of at least three different plastics.How recycling is carried outBy handworkersconsumerThe success of the operation relies on:1. Manufacturers 2. The public and consumers3. G

20、overnment expensiveManufacturers just use one single type of plastic to make plastic products.The articles need to be clearly labeled to show the name of this plastic.Recycling code PET (Polyethylene terephthalate) 聚对苯二甲酸乙二酯Recycling codeHDPE (high density polythene) 高密度聚乙烯Recycling codePVC (Polyvinyl chloride) 聚氯乙烯Recycling codeLDPE (low density polythene) 低密度聚乙烯Recycling codePP (Polypropene) 聚丙烯Recycling codePS (polystyrene) 聚苯乙烯The public need to be educated on the common sense of recycling.Consumers should be encouraged to purchase plastic products properly coded with the