Characters: Host, Expert, 3 Audience Members, 1 producer
Host enters to a cheering audience. We see “APPLAUSE” sign held up by producer.
Host: A very good evening and welcome to THE SCIENCE SHOW. This week, we’ll be talking about plastics! Do you guys like plastics?
Host: Have you ever felt like a plastic bag?
Host: That’s very strange. Without further ado, let’s bring out our expert of the day, Pauly Mer.
Expert walks out and takes a seat.
Host: Welcome to our show. Mr Pauly Mer, lemme ask you, what are polymers?
Expert: Polymers are typically macromolecules, which are derived from petrochemicals. They consist of repeating monomer units, which are strung together to form the larger macromolecule.
Host: Wow. So informative. Anyway, why are some plastics hard, while others are soft. Some are flexible, others rigid?
Expert: Plastics vary in their melting points, elasticity, rigidity, tensile strength and crystallinity, among many other physical and chemical properties. For example, plastics, in general, are lightweight, although their weights vary significantly from each other.
Host: That’s fantastic. Let’s take a question from the audience. (Randomly points at audience)
Audience 1 walks up to microphone.
A1: OH MY GOSH! I’m so happy to finally meet you! Ok, calm down, calm down. I wanted to ask: What’s your least favourite polymer?
Expert: Well, I really hate High Density Polyethylenes, or HDPEs.
A1: OH MY GOSH! Me too!
Host: Ok, that’s enough, audience member! Go sit down. Ok HDPEs are made up of compact polyethylene macromolecules. Let’s take a look at what that looks like.
Cut to Ethylene Macromolecule.
Host: Look at that nasty little thing. So, how are HDPEs formed?
Expert: (Cut to Ethylene Production video and http://www.chemistryland.com/PolymerPlanet/Polymers/EthyleneChainReactionLrg.gif ) Petroleum is cracked to produce ethylene gas. The ethylene gas molecules are then linked together to form polymers and produce polyethylene. This process is called addition polymerisation, and is conducted under low pressure, with an aluminium-based catalyst.
Host: Now it’s time for another audience question. You! (points to audience)
A2: Um, I was, um, wondering… what makes HDPE so useful?
Expert: [with keywords and host getting bored/ producer asking to speed up/ A2 sleeping/ A1 still being a fan] Well, I hate to say this but HDPE is pretty useful. It has a high density. Because of the absence of branches, the long, linear macromolecules are able to be packed closely to each other. It also has a relatively High Melting Point. Since the macromolecules are packed close together and the intermolecular forces of attraction are much stronger. These stronger forces also give HDPE a higher relative strength. HDPE is rather rigid, due to its regular, close packing, giving it a high tensile strength. HDPE is also chemically inert due to its existence as a stable compound, and since it’s a large macromolecule.
Due to its properties, HDPE plastics are used to make a variety of durable products, including:
- Ballistic plates
- Fuel tanks
- Water pipes
- Hard hats
- Folding chairs and tables
- Lunchboxes (Show Buzz Lightyear lunchbox)
Host: Oh, you’re done? Ok great! Well, since you took so long to answer his question, we only have time for one final audience question. You! (points to audience)
A3: Hey, expert, what’s your problem? What’s wrong with HDPE? I love HDPE, okay? In fact, my favourite Buzz Lightyear lunch box is made of HDPE. (Show same Buzz Lightyear lunchbox) What is wrong with HDPE?
Expert: Well, HDPE isn’t biodegradable. In fact, it takes 1000 years for a HDPE plastic bag to dissolve in the environment. The micro-organisms that are responsible for decomposition aren’t able to recognize how to break down a carbon-carbon bond.
A3: Then, why can’t we just manufacture plastics out of peptide bonds?
Expert: Well, it’s simply because peptide bonds have a very short shelf life. So if your lunchbox was made with peptide bonds, you’ll probably only have it for 2 days.
Cut to producer indicating that it’s time to wrap up.
Host: Ok, that’s all the time we have for you, folks! Have a great night and remember to keep recycling.