INFORM November/December 2025

BIOPLASTICS

inform November/December 2025, Vol. 36 (10) • 19

Cashew nut liquid as a PVC plasticizer

Adélaïde Gartili and co-authors

In the plastics market, PVC stands out as one of the most widely used thermoplas tics. Recognized for its exceptional per formance and cost-effectiveness, PVC has numerous applications in the production of a wide range of products, from rigid to flex ible items. The intrinsic hardness and brit tleness of PVC arise from the polarity of the C-Cl bond and robust dipole–dipole interac tions, constraining polymer chain mobility. Consequently, various plasticizers have been employed to enhance the stretchability and processability of PVC. Because of their remarkable efficiency and afford ability, phthalate esters, notably diethylhexyl phthalate (DEHP), are the most used plasticizers. However, exter nal plasticizers can leach with age and time. Due to their suspected endocrine disruptor effect in humans and their reproductive toxicity, phthalates are now restricted if not prohibited. Moreover, the unsustainable production of phthalates from crude oil does not align with the plastics industry’s growing demand for bio-based, renewable plas ticizers derived from sustainable feedstocks.

• PVC requires plasticizers to improve flexibility, but conventional phthalate-based options pose toxicity and environmental concerns. • Cashew nutshell liquid (CNSL), a non-edible byproduct of cashew processing, contains cardanol and cardol, which show strong potential as sustainable, bio-based PVC plasticizers. • Researchers tested CNSL-derived esters, showing that acetylated CNSL mixtures (cardanol–cardol) enhance mechanical strength, flexibility, and thermal stability of PVC films, while maintaining lower gelation temperatures than current bio-based alternatives. • The results indicate that acetylated CNSL mixtures are viable candidates for flexible PVC applications such as packaging, overcoming a distillation step that once limited the commercialization of these bio-based plasticizers.