INFORM November/December 2025

inform November/December 2025, Vol. 36 (10) • 23

observed that the T onset was similar for all derivatives. The maximal viscosity increases as well as the speed of absorption of the plasticizer by the PVC particles with a higher amount of cardol in the plastisol. The difference in speed can be explained by the fact that cardol has two ester groups, which can interact with PVC chains, whereas cardanol derivatives have only one. This may also be true for ELO and ESBO, which have more polar groups due to a higher number of epoxy groups. However, such dif ferences between the two can be observed and may be due to varying epoxy rates. Thus, plastisol plasticized with cardol derivatives exhibit comparable behavior to ELO reference, highlighting their poten tial use as plasticizers, better than A-C2, which shows poor behavior, in accordance with the literature. Also, it has to be noted the observation of two peaks in maximum viscosity for ESBO and A-C2 derivatives and mixtures. Indeed, the gelation process results in a significant increase in both modulus and viscosity, reaching a plateau or maximum. Toward the end of gelation, further temperature increase leads to a decrease in viscosity, likely due to thermal expansion and the melting pro cess. Then a shoulder is observed and may be interpreted as a decrease in gelation velocity. This may be attributed to certain resin parts absorbing the plasticizer at slower rates than others. On the rheological traces, a bell-shaped curve is observed for all samples, indicating viscoelastic behavior. This profile indicates a transition between solid and liquid states within the material. The gelation temperature (Tgelation) of the plastisol corresponds to the intersection of both modulus lines, denot ing significant changes in the properties of the material. The gelation temperatures for the industrial biobased plasticizers ESBO and ELO were at 69 °C and 78 °C, respectively, compared to Tonset around 66 °C and Tendset around 115 °C. The gelation temperature for plastisol containing CNSL mixtures increased with the amount of cardol, ranging from 48 °C to 53 °C. Plastisol containing pure B-C2 has a slightly higher gelation temperature (59 °C). The B-C2 compound exhibits a lower gelation temperature compared to industrial biobased plasticizers and may be beneficial. Indeed, plastisol with lower gelation temperatures may offer improved flexibility and processability, as they can be processed at lower temperatures and may require less energy input during manufacturing. However, it should be reminded that other additives are usually used in the formulation, and the overall performance requirements and compatibility of the B-C2 compound with other additives in the formulation have to be ensured. The lower temperature gelation of B-C2 is due to its molecular configuration, as molecules with certain functional groups, like ester groups, can interact with polymer chains, forming intermolecular bonds or networks at lower tempera tures. These interactions increase viscosity and lead to gelation at lower temperatures compared to other plasticizers. In sum mary, the ability of a molecule to induce gelation at lower tem peratures depends on its interaction and binding with polymer chains, which stabilize the gel structure at lower temperatures.

To summarize, B-C2, compared to A-C2, increases the max imal viscosity and accelerates the speed of plasticizer absorp tion by PVC particles, thereby enhancing plasticizing efficiency and mimicking the behavior of ELO. Additionally, it distinguishes itself by its gelation temperature, which resembles that of phthalates while remaining lower than that of bio-sourced alter natives like ESBO and ELO. This characteristic confers a signifi cant advantage upon B-C2 in various industrial applications. Its moderate gelation temperature makes it suitable for manufac turing processes requiring relatively lower temperatures, high lighting the promising application of CNSL derivatives containing B-C2 derivatives as biobased plasticizer for PVC. This work depicts a simple method for producing diverse plasticized PVC films, characterized by favorable mechanical properties and adequate thermal stability, with esters syn thesized from bio-sourced, non-edible, CNSL. The research involved synthesizing various esters from different CNSL con taining naturally varying amounts of cardanol–cardol mixtures. This approach aims to investigate the potential use of this nat ural mixture as plasticizers, prioritizing it over the utilization of pure cardanol or cardol due to the time-consuming, energy-in tensive, and costly processes required for their separation. The findings reveal significant potential for the applica tion of acetylated technical CNSL (A_B 80_20 C2) as a bio based alternative to phthalate plasticizers in various flexible PVC products. These findings could streamline the process and reduce the cost associated with separating cardanol from car dol. The study demonstrates that CNSL as a mixture exhibits interesting properties compared to cardanol alone. Moreover, in comparison to phthalates and other com mercial biobased plasticizers, acetylated technical CNSL emerges as a promising alternative. Plastisols derived from it display a lower gelation temperature (48 °C) compared to ELO (78 °C). PVC films plasticized with technical CNSL-C2 exhibit superior mechanical properties with 449 percent elongation and 14 MPa tensile strength, surpassing DEHP at 259 percent and 38 MPa, respectively. The thermal stability was main tained isothermally at 200 °C without any weight loss for up to 10 min and presents acceptable leaching behavior. Moreover, technical acetylated CNSL offers UV blocking capabilities up to 375 nm, exceeding DEHP (300 nm), making it suitable for food packaging films. The author Adélaïde Gartili and co-authors Vincent Lapinte, and Sylvain Caillol perform research at the Université de Montpellier, France. Benoit Briou works at Orpia Innovation, Montpellier, France. For questions contact Sylvain Caillol at sylvain.caillol@enscm.fr. This article contains excerpts from an open access research paper published in the Journal of the American Oil Chemists’ Society titled, “Valorization of CNSL as a Sustainable Solution for PVC Plasticization: A Comprehensive Study of Cardanol–Cardol Mixture.” To read the full paper, including missing citations, sections, and figures visit https://doi.org/10.1002/aocs.12955.