the additives in detergent and their respective function

1. Modern detergents used for washing clothes usually contains a few types of
additives to :
                                          a) Increase their cleaning power.

b) Make them attractive and saleable.

2. Only about 20% of the substances in a detergent are cle4ansing agents (sodium
alkyl sulphate or sodium alkylbenzene sulphonate). The other substances are
additives. The examples of addictives and their functions are described as follows:


3. Builders : Sodium tripolyphosphate (Na5P3O10)

a) Sodium tripolyphospathe is usd to soften hard water. In the presence of

sodium tripolyphosphate, Ca2+

ions and Mg2+ ions are removed.

b) Sodium tripolyphosphate increases the pH value of water. In this way,

muddy dirt can be removed.

4. Whitening / bleaching agents : sodium perborate

a) Bleaches (bleaching agents) remove coloured stains by oxidation process.

When coloured stanis are oxidized, the colour will disappear.

b) The whitening (bleaching) agents commonly used in detergent are sodium

perborate (NaH2BO43H2O). Sodium perborate decomposes in hot water to

release oxygen (an oxidising agent) which is responsible for the whitening

(bleaching) action.

c) Unlike chlorine, oxygen does not bleach the colour of dyes are not

damaging to fabrics. When properly used, the perborate bleaches make

fabrics whiter than chlorine bleaches and the colourful dyes of the fabrics

do not fade when dirty stains are removed.

d) Besides sodium perborate, sodium hypochlorite, (NaCIO) can also be used

as bleaches in detergents. The IUPAC name of sodium hypochlorite is

sodium chlorate (I).

e) Sodium hypochlorite releases chlorine that bleaches with dirty stains.

However, high concentrations of chlorine can be quite damaging to fabrics.

These bleaches do not work well on synthetic fabrics (polyster fabrics),

often causing a yellowing rather than the desire whitening. Also chlorine

causes the dyes on fabrics to fade.

5. Biological enzymes : Amylase, lipase, and protease

a) Protein stains such blood, milk, and tomato sauce cannot be removed by

the ordinary detergents because these types of stains are insoluble in

water.

b) Biological enzymes in detergents can break down fat and protein

molecules in food stains. The fatty acids, glycerol and amino acids

produced are soluble in water and are removed during washing.

6. Brighteners

a) Figure below shows the action of brighteners. The brighteners absorb the

invisible ultra-violet and re-radiate it as blue light.

b) Brighteners make fabrics appear whiter and brighter because the blue light

can hide any yellowing on the fabrics. Blue light added to the yellow light
reflected on old fabrics make them look white.

7. Drying agents ; Sodium sulphate and sodium silicate

Anhydrous sodium sulphate and sodium silicate (Na2S2O3) are used as drying
agents to ensure that the detergent in powdered firm is always in a dry condition.

8. Stabilisers

a) The functions of stabilizers is to prevents the formation of foam.
b) In an automatic washing machine, excessive foam can stop the pump
working. So, washing powders for automatic washing machine are made
using detergents that are good at removing and emulsifying grease, but do
not produced foam.

9. Perfumes

Perfumes are added to make clothes smell fresh and clean.