**5. Conclusion**

Resoles and novolacs resins are the major products of reaction of CNSL with formaldehyde. While novolac results from acid-catalyzed reactions, resoles are a product of base-catalyzed

CNSL can be polymerized by different methods. This includes addition polymerization through the side-chain double-bonds using cationic initiators such as diethylsulphate, condensation polymerization through the phenolic rings with aldehydic compound, e.g. formaldehyde, oxidative polymerization, polymerization after chemical modification to produce specialty properties, etc. The most common method is condensation reaction with formaldehyde. The CNSL-based polymers offer advantages such as improved flexibility and reduced brittleness, solubility in organic solvents, improved process ability, compatibility with

CNSL were successfully applied as a thermosetting wood adhesive for wood panels to reduce formaldehyde emission. These renewable phenolic compounds give excellent adhesive performance, good moisture resistance and tend to give a lower formaldehyde emission than

CNSL may be a weak promoter of carcinogenesis but no mutagenic or carcinogenic activity has been reported [64]. Epidemiological studies suggested that CNSL may contribute to oral sub-mucous fibrosis [65]. In addition, its phenolic components exerted several biological activities, including antioxidative properties [66, 67], inhibition of acetyl cholinesterase and

There is no direct evidence regarding the toxicity of CNSL or its major phenolic components. However, the effluent generated during the processing of the cashew nut could be considered potentially harmful to the environment due to its high phenol content. The hazardous effects of phenolic compounds have been extensively studied. According to [70], a concentration above 1 mg/L can affect aquatic life, while [71] recognizes deleterious effects at concentrations

As previously mentioned, data on the chemical composition of the cashew nut industry effluent are scarce, but preliminary analysis showed high phenol content due to the cardol, cardanol and anacardic acid of CNSL. The high toxicity observed for the isolated phe‐

other polymers, high performance and resistance to microbes, insects and termites.

reactions.

18 Advances in Petrochemicals

UF resin [62, 63].

as low as 1 µg/mL.

**4.1. Environmental impact**

membrane perturbation [68, 69].

The report has highlighted various chemicals obtainable from CNSL both directly and indirectly. This inexhaustible listing presents CNSL as a very important, reliable source of raw material for petrochemical industry. It is a good, promising supplement and/or alternate to petroleum, which is currently facing depletion globally.

Varied CNSL compositions with varying modes of extraction are a vantage opportunity with potential for multiple applications.

Though CNSL contains phenolics, its products are highly environmental friendly. However, efficient treatment strategy may be inevitable to reduce environmental impact associated with the production industry.
