We will be pleased to add to this glossary if there is the need. Please contact modip@aub.ac.uk with suggested additions.
Glossary entries are cross-referenced in bold.
Acid
Any water-soluble substance giving solutions of low pH, such as sulphuric acid.
Alkali
Any water-soluble substance giving solutions of high pH, such as sodium hydroxide.
Aromatic
A type of organic compound containing atoms arranged in a stable ring system.A simple example is benzene, the molecule of which is a ring of six carbon atoms each with one hydrogen atom attached.
Aqueous
In or containing water, e.g. an aqueous solution is one in which the substance is dissolved in water.
Atom
The smallest subunit of matter. Subatomic particles, electrons, protons and neutrons, are the building blocks of atoms and they give rise to 118 varieties.These are known as elements e.g. oxygen, carbon, iron, etc.
Carbohydrate
An organic compound where the hydrogen and oxygen atoms are in the ratio 2:1 respectively (i.e. H2O). Examples are cellulose, starch, and sugars such as sucrose, glucose and fructose.
Cellulose
An insoluble substance which is the main constituent of plant cell walls and of vegetable fibres such as cotton. It is a polysaccharide consisting of chains of glucose molecules, end to end.
Copolymer
A polymer comprising subunits of different types joined together. Copolymerisation is the process for making copolymers.
Dechlorination
The process of treating a substance to remove all or some of the chlorine atoms.
Diol
An organic compound containing two hydroxyl groups per molecule (not
attached to an aromatic ring).
Dispersion
Very small particles (in this context polymer particles) dispersed in water, sometimes called an emulsion or a latex, usually manufactured via polymerisation of a dispersion of monomer in water (emulsion polymerisation).
Grafted
In the context of polymers, this means joined with a strong chemical bond.
Hydroxyl group
A hydrogen atom bonded to an oxygen atom. Hydroxyl groups typify alcohols
or phenols.
Hydrolysis
Any decomposition reaction which is caused by water. Acids or alkalis are usually involved and hasten such a reaction. For example the acetate groups of poly(vinyl acetate) can be removed by 'hydrolysis' with water and sodium hydroxide to form poly(vinyl alcohol) and sodium acetate.
Macroglycol
A diol of much increased molecular chain length.
Membrane
A very thin film, usually composed of a polymer. Gore-Tex membrane is a porous film of polytetrafluoroethylene approximately 0.01mm thick.
Molecule
A group of atoms of fixed number and position constituting the smallest unit defining a substance. For a more detailed explanation see the section Simple polymer chemistry.
Molecular weight
The weight of all the atoms in a molecule relative to one hydrogen atom.
Monomer
A substance which is the subunit of a polymer.
Organic
In general, adjective describing compounds, the molecules of which contain carbon atoms. Organic chemistry is the branch of chemistry dealing with such compounds. There are exceptions though, such as calcium carbonate and carbon dioxide. Inorganic chemistry describes compounds without carbon.
pH
A measure of the acidity or alkalinity of an aqueous solution on a scale of 0 - 14. A pH of 7 is neutral. A solution with a pH of 2 would be a strongly acid solution. A solution with a pH of 12 would be a strongly alkaline solution.
Plasticiser
A substance added to a polymer to make it more flexible. Most commercial polymers are sufficiently flexible by their nature, but some, notably PVC, can be either plasticised or unplasticised (e.g. uPVC for window frames isunplasticised).
Polymer
A substance comprising multiple repeating groups of atoms (molecules). Fibres are polymers in which the molecules are arranged in long chains.
Polymerise
To carry out the process of joining up groups of atoms (molecules) into polymers. The molecules can be the same or different. In the latter case the process is copolymerisation.
Polysaccharide
A carbohydrate (e.g., starch or cellulose) consisting of a number of sugar molecules (e.g., glucose) bonded together.
Proteins
Proteins are naturally occurring polymers serving many functions in all life forms. They are composed of numerous amino acids of different structures.The protein in milk is called casein, that in corn, zein and that in silk, sericin.
Pyrolysis
The process of heating until decomposition occurs.
Reaction (chemical)
Changing of a substance at the molecular level. Hydrolysis and polymerisation are examples of chemical reactions.
Semi-synthetic
Describes products which are man-made using naturally occurring starting materials.
Synthetic
Describes products which are completely man-made (synthesised).