Cashew nut shell liquid (CNSL) - a versatile monomer for polymer synthesis

Abstract

Cashew nut shell liquid (CNSL) is a by-product of the cashew industry. It is a naturally occurring substituted phenol which can take part in a variety of reactions. It is a cheap and renewable substance and can be employed for the manufacture of a multitude of useful products. It can replace phenol in many applications with equivalent or better results. CNSL by itself is useful for insecticidal, fungicidal, anti-termite, and medicinal applications, and as an additive, in many plastic formulations. Resins derived from CNSL are employed widely in the fields of friction materials, automobiles, surface coatings, adhesives, laminates, rubber compounding, and have several miscellaneous applications. Greater utilization of CNSL as a monomer for indusrial polymer products can be an attractive proposal in view of its low cost, abundant availability, and chemically reactive nature, amongst other attributes. This review gives an accounts of the composition, extraction, reactions, and applications of CNSL based on the available literature.