2 What makes synthetic polymers so useful? Synthetic polymers are so useful. Synthetic polymers are plastics. They are useful, because they can be recycled, they are cheap, they are light and strong. Plastics' versatility allow it to be used in everything; car parts, doll parts, soft drink bottles, refrigerators . Plastics help make your life easier and better.
3 Many synthetic polymers are not biodegradable. What does this mean? Biodegradable means- (of a substance or object) capable of being decomposed by bacteria or other living organisms.One advantage of polymers is that they are unreactive, so they are suitable for storing food safely. Unfortunately, this property makes it difficult to dispose of polymers. They are normally buried in landfill sites or incinerated.Most polymers, including poly(ethene) and poly(propene), are not biodegradable. This means microorganisms cannot break them down, so they may last for many years in rubbish dumps.However, it is possible to include chemicals that cause the polymer to break down more quickly. Carrier bags and refuse bags made from degradable polymers are already available.
4 Describe the problems caused by the disposal by incineration and in landfill sites… Waste polymers are disposed of in landfill sites. This uses up valuable land, and suitable sites often fill up quickly.IncinerationPolymers release a lot of heat energy when they burn. This energy can be used to heat homes or generate electricity. But there are problems with incineration. Carbon dioxide is produced, which adds to global warming. Toxic gases are also produced, unless the polymers are incinerated at high temperatures.
5 Many polymers can be recycled, explain the challenges of recycling polymers… Many polymers can be recycled. This reduces disposal problems and the amount of crude oil used. But first the different polymers must be separated from each other. This can be difficult and expensive.
6 Explain why scientists are developing ways of making some polymers biodegradable… Scientists are developing ways of making polymers biodegradable, due to the amount of room they take up at landfill sites. Landfill sites are already filling up at a very fast rate and with items that don’t biodegrade, it’s filling up even faster. If they do make some polymers biodegradable that will be mean the majority of them will either be recycled or they will biodegrade.New types of polymersChemists are developing new types of polymers. Most polymers, including polyethene and polypropene, are not biodegradable. This means microorganisms cannot break them down, so they may last for many years in rubbish dumps. However, it is possible to include chemicals that cause the polymer to break down more quickly. Carrier bags and refuse bags made from degradable polymers are already available.Some polymers are water-soluble, which means they dissolve in water. These polymers are often used to wrap products such as dishwasher tablets and pouches containing detergent for washing machines.
7 Describe the benefits and drawbacks of making disposable bags from corn-starch… Advantages 1.Comes from corn, which is a renewable resource 2.Does not contain toxins 3.Producing this kind of plastic creates much less greenhouse gas emissions than conventional plastic production (a reduction of 68 percent) 4.Corn starch plastic can be composted in facilities for industrial composting 5.65 percent less energy is needed to produce corn-based plastic than to produce conventional plastic 6.PLA plastic is competitive with conventional plastic in terms of cost, since petroleum prices are only going up 7.PLA is more safe, since there is no danger of explosions in its production (as is the case with using petroleum)Disadvantages 1.Although PLA is compostable, there are very few facilities where this can actually be done (in the USA only about 113 sites for this exist) 2.Most likely consumers will not compost corn starch plastics properly, and just put them in regular recycling. This could contaminate the recycling stream 3.Composting PLA in large quantities could undermine conventional composting, since the polymer contained in corn-based plastic makes regular compost more acidic. 4.Since there is a lack of adequate infrastructure to compost PLA, most of it will probably still go into landfills. 5.MRFs – Material Recovery Facilities – are responsible for paying for sorting and disposing of PLA 6.Because PLA is derived from corn, there are moral issues with it being used for packaging, since there are people in the world dying of hunger 7.PLA is mostly produced from genetically modified corn