C1bL3 Uses of Polymers

Key Words

 

Bio degradable - material that can be broken down using micro-organisms.

Cross- linkages - Chemical bonds that form between adjacent polymer chains.

Kevlar - trade name for a poly-para-aramid fibre made by Dupont.  It can stop a bullet..

Polymer chains - very long chain molecules made up of many repeating sub-units that form a plastic material.

Polyurethane - A light polymer that is often used as a foam to fill cavities.

PVA - a polymer that is suspended in water and can act as a glue.

Teflon - poly-tetra-fluoro-ethene (PTFE) a very slippery polymer.

Viscosity - a gooey liquid is viscous.

Test Yourself

Homework
Chemistry GCSE
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Grade E

Teflon ® (PTFE) is a very slippery polymer, consisting of many tetra-fluoro-ethene monomers.  It is used for:

  • Non-stick pans;
  • Bearings.

Polyurethane is a very tough and light material.

Grade C

Some polymer chains can be joined together by bonds called cross-linkages, or bridges.  In complex polymers like proteins the cross-linking is essential for their function.

Polyvinyl alcohol (PVA) makes a white emulsion in water.  If sodium borate (borax), Na2B4O7, is added, it makes cross-links between the chains of PVA, resulting in a gooey slime.  The viscosity is determined by temperature and concentration of the borax.

 

Some other uses for polymers:

  • Packaging;
  • Dental prosthetics (false teeth to you);
  • Waterproofing;
  • Wound dressings.

There are lots of others, too.

 

Grade A

Some polymers can be designed to regain their shape if they have been deformed.  These are shape-memory polymers.  The deformation can be removed by heating with a hair dryer.

Biodegradable materials can be broken down by  micro-organisms in the environment.  Many polymers are not biodegradable, and can last for many years in land-fill..  Others are, and will break down.  Also internal stitches used in operations are carried out with a biodegradable thread.