Incorporation of Cellulose Nanocrystals into a Cottonseed Oil-Based Network Polymer: Effect on Mechanical Properties

Abstract

The detrimental issues surrounding the accumulation of traditional plastic waste are well known. A myriad of research has been conducted in the past few decades related to the synthesis of polymers using plant oils as starting monomers to obtain polymers from renewable sources. These polymers can be biodegradable and, therefore, can decrease further plastic waste accumulation. Although many studies have been conducted on the polymerization of soybean oil (SBO), comparatively few studies have been conducted on the polymerization of cottonseed oil (CSO). CSO is an excellent candidate for a plant-based polymer due to the abundance, renewability, and potential biodegradability of the synthesized polymers. We have synthesized cottonseed oil network polymer (CNP) from epoxidized cottonseed oil (ECSO) using maleic anhydride (MAL) as a crosslinker. Further, cellulose nanocrystals (CNCs) have been successfully incorporated into CNPs to produce a nanocomposite. Neither solvent exchange of the aqueous CNCs nor surface compatibilization was required before mixing with the ECSO and subsequently with maleic anhydride (MAL). FTIR confirmed the presence of CNCs in the polymer matrix, and the effects of CNCs on the mechanical properties were investigated. CNCs alter the mechanical properties of the crosslinked polymer, with an increase in stiffness/modulus correlating with an increasing CNC content. The polymer's thermal properties, as investigated by thermodynamic analysis and differential scanning calorimetry, have not undergone significant changes for the CNC concentrations considered here. Overall, this study demonstrates that CNC can be successfully incorporated into a network polymer derived from CSO, resulting in altered mechanical properties and demonstrating the possibility of tailoring them for various applications.