Using Plastics Noadswood Science, 2011 Using Plastics To be able to explain the properties and uses of plastics Tuesday, February 09, 2016 Polymers What are polymers Polymers are huge molecules which are made up of lots of smaller molecules (monomers) which have been joined together Properties Different polymers can be made by using different monomers these polymers can have very different properties Polymers have properties that depend on the chemicals they are made from, and the conditions in which they are made Modern polymers have many uses, including: - Waterproof coatings Fillings for teeth Dressings for cuts Hydrogels for making soft contact lenses and disposable nappy liners Shape memory polymers for shrink-wrap packaging Polymer Branches Polymer molecules can have branches coming off them, which change their properties, e.g. LDPE and HDPE LDPE low-density poly(ethene) HDPE high-density poly(ethene) Branches on polymerManyFew Relative strengthWeakStrong Maximum useable temperature ( o C) 85 o C120 o C Polymer Problems One of the useful properties of polymers is that they are unreactive, so they are suitable for storing food and chemicals safely, but this property makes it difficult to dispose of polymers Most polymers, including poly(ethene) and poly(propene) are not biodegradable meaning that micro-organisms 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 such degradable polymers are already available Polymer Problems Polymers can be burnt or incinerated they release a lot of heat energy when they burn and this can be used to heat homes or to generate electricity There are problems with incineration as carbon dioxide is produced, which adds to global warming Toxic gases are produced unless the polymers are incinerated at high temperatures Polymer Problems Many polymers can be recycled reducing the disposal problems and the amount of crude oil used It is crucial different polymers are separated from each other first, and this can be difficult and expensive to do Modern Plastic Bags Many polymers can be recycled reducing the disposal problems and the amount of crude oil used Some modern plastic bags are now being made from biodegradable polymers such as cornstarch which will increasingly provide useful replacements for the main polymers currently used Research Using the laptops complete a search for common polymers include what their properties are and how they are used What new polymers are currently being developed, and what benefits do these have? Produce an A4 poster / PowerPoint / movie containing all the information you have collated You may also wish to identify how each of the polymers can be disposed of