Chemical Composition of CNSL

CNSL is a mixture of four components: all are substituted phenols - anacardic acid, cardanol, cardol and 2-methyl cardol. The first two are monohydric phenols whereas the other two are dihydric phenols. In the nut, CNSL occurs mainly as anacardic acid(~90%) and cardol around slightly lower than 10%. During the hot-oil bath process for extraction of CNSL, anacardic acid gets decarboxylated to cardanol. So in the technical grade CNSL, the main components will be cardanol and cardol and of course, some polymerised CNSL.

CNSL can be extracted by the expeller method but the oil has to be heated after extraction to convert anacardic acid to cardanol. The expelled and heated CNSL will have less amount of polymerised CNSL. However, if there is a requirement for pure monomers, the best source will be solvent extracted CNSL. Each component again is a mixture of four structurally related monomers, the difference being only in the degree ofunsaturation. Thus, cardanol is a mixture of a four components: saturated (~5%), monoene (~49%), diene(l6.8%) and triene (29.3%). (This makes the chemistry of addition polymerisation essentially complex). Thus, CNSL contains a total of 16 components, which makes it a complicated system.

Advantages of CNSL based Polymers

• Improved Flexibility and reduced brittleness.
• Solubility in Organic Solvents.
• Improved Processability.
• Low Fade Characteristics for Friction.
• Resistance to 'Cold Wear'.
• Good Electrical Resistance.
• Better Water Repellence.
• Improved alkali and acid resistance.
• Compatibility with other polymers
• Antimicrobial Property.
• Termite and Insect Resistance.
• Structural Features for Transformation into High Performance Polymers.