Polymers in everyday things

Many people think of polymers simply as plastics used for packaging, in household objects and for making fibres, but this is just the tip of the iceberg.

Areas in which polymers are important include:

1. Kitchen applications and food
2. Medical products for wound care, dentistry and in contact lenses
3. Sportswear and sporting materials
4. Protective equipment for work and leisure activities
5. Home and personal care products.

Further information on some of the uses of polymers in these areas is given below. Polymers are produced by addition reactions or condensation reactions.

The Polymers in everyday things activity set consists of three student worksheets:

• Polymers in everyday things – contact lenses
• Polymers in everyday things – dentistry
• Polymers in everyday things – mountaineering.

Each worksheet provides background information and a series of questions that guide students to relate the properties of materials to their uses in particular contexts. Students also compare the advantages and disadvantages of some synthetic materials with those of naturally occurring ones.

Notes on using the activities

The format of the activities is quite flexible and they can be used as a teaching aid when a teacher is present or as material for part of a cover lesson when a specialist teacher is not available. Students can use knowledge from previous lessons, reference books and internet searches (if web access is available) to help them answer the questions.

To get the most out of Polymers in everyday things – mountaineering, internet access is advisable.

Each activity requires students to read the information provided on the worksheet and answer some associated questions. A number of suggested questions have been provided which teachers may use or adapt to suit the needs of their students.

Once this written exercise has been completed, it is advisable to organise a follow-up class or group discussion about the information on the worksheet and students’ answers to the questions.

This will help ensure students have fully understood the material and will allow them to express their opinions about what they had read. You may also wish to set students the task of further investigating some aspect of the topic using reference books and/or the internet. The information they gather could be used to produce a poster or presentation, for example.

Polymers and food

Polymers are used very widely in the production, distribution, packaging and preparation of food. Some examples of such uses are listed below.

Farming:

• Sheeting to protect crops
• Encapsulation of seeds (gels and nutrients)
• Protective clothing for farm workers.

In the kitchen:

• Storage (sealable containers, cling film, vacuum packing machines)
• Food preparation (plastic cutting boards, microwave-safe transparent containers, flexible utensils, cook-in-the-bag techniques).

In food

• Swelling of starch – perfect chips, roast potatoes, risotto.
• Denaturation of protein and connective tissue – cooking meat at low temperature.
• Thickening of soup using starch, gelatine (a heteropolymer of amino acids) or insulin (a non-digestible polysaccharide).

Polymers in medical products

Contact lenses

The material used in contact lenses was originally made by bulk free radical polymerisation, which was carried out very slowly to minimise stress. The polymer rods were then cut into buttons, which were shaped on a lathe to give the correct optical shape. Nowadays, cast moulding with UV initiation is the preferred technique.

Polymers in sport

Sporting equipment often consists of many different types of polymer and can usefully be broken down into clothing and footwear, protective equipment, and games or event equipment.

• Trainers (athletic footwear)
• Protective equipment
• Polymers in games or event equipment
• Golf balls
• Carbon fibre in sport

Polymers are a part of everyday life and examples can be found almost anywhere. Many people think of polymers simply as plastics used for packaging, in household objects and for making fibres, but this is just the tip of the iceberg. Polymers are used in all sorts of applications you might not have thought much about before.