Chemistry_Grade_10-12 (1).pdf

But in many cases these natural organic polymers

Info icon This preview shows pages 205–208. Sign up to view the full content.

View Full Document Right Arrow Icon
from rubber trees. But in many cases, these natural organic polymers didn’t have the characteristics that were needed for them to be used in specific ways. Natural rubber for example, is sensitive to temperature and becomes sticky and smelly in hot weather and brittle in cold weather. In 1834 two inventors, Friedrich Ludersdorf of Germany and Nathaniel Hayward of the US, independently discovered that adding sulfur to raw rubber helped to stop the material from becoming sticky. After this, Charles Goodyear discovered that heating this modified rubber made it more resistant to abrasion, more elastic and much less sensitive to temperature. What these inventors had done was to improve the properties of a natural polymer so that it could be used in new ways. An important use of rubber now is in vehicle tyres, where these properties of rubber are critically important. Interesting Fact erest Fact The first true plastic (i.e. one that was not based on any material found in nature) was Bakelite , a cheap, strong and durable plastic. Some of these plastics are still used for example in electronic circuit boards, where their properties of insulation and heat resistance are very important. 191
Image of page 205

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
10.5 CHAPTER 10. ORGANIC MACROMOLECULES - GRADE 12 10.5.1 The uses of plastics There is such a variety of different plastics available, each having their own specific properties and uses. The following are just a few examples. Polystyrene Polystyrene (figure 15.2) is a common plastic that is used in model kits, disposable eating utensils and a variety of other products. In the polystyrene polymer, the monomer is styrene , a liquid hydrocarbon that is manufactured from petroleum. CH CH 2 polymerisation CH CH 2 CH CH 2 CH CH 2 etc Figure 10.7: The polymerisation of a styrene monomer to form a polystyrene polymer Polyvinylchloride (PVC) Polyvinyl chloride (PVC) (figure 10.8) is used in plumbing, gutters, electronic equipment, wires and food packaging. The side chains of PVC contain chlorine atoms, which give it its particular characteristics. C C H H Cl H n Figure 10.8: Polyvinyl chloride Interesting Fact erest Fact Many vinyl products have other chemicals added to them to give them par- ticular properties. Some of these chemicals, called additives, can leach out of the vinyl products. In PVC, plasticizers are used to make PVC more flexible. Because many baby toys are made from PVC, there is concern that some of these products may leach into the mouths of the babies that are chewing on them. In the USA, most companies have stopped making PVC toys. There are also concerns that some of the plasticizers added to PVC may cause a number of health conditions including cancer. Synthetic rubber Another plastic that was critical to the World War 2 effort was synthetic rubber , which was produced in a variety of forms. Not only were worldwide natural rubber supplies limited, 192
Image of page 206
CHAPTER 10. ORGANIC MACROMOLECULES - GRADE 12 10.5 but most rubber-producing areas were under Japanese control. Rubber was needed for tyres and parts of war machinery. After the war, synthetic rubber also played an important
Image of page 207

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 208
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern