Introduction of Ionic Liquids as Highly Efficient Plasticizers and Flame Retardants of Cellulose Triacetate Films

As a promising biodegradable polymer, cellulose triacetate (CTA) was synthesized and plasticized with ionic liquids to produce flexible biocomposite films multi-end-use. Initially, CTA polymer was synthesized from industrial waste cotton using a heterogeneous pathway. Subsequently, four ionic liquids, namely 3- hexyl-1-methyl imidazolium acetate [C6MIM][Ac], 3-hexyl-1-methyl imidazolium hexafluorophosphate [C6MIM][PF6], N-hexyl N,N,N-triethylammonium acetate [N-2226][Ac] and N-hexyl N,N,N-triethylammonium hexafluorophosphate [N-2226][PF6] were synthesized and used as plasticizer materials of CTA film. Indeed, the films were prepared at room temperature using the solution-casting method, and the effects of ionic liquids on their morphological, mechanical, and thermal properties were evaluated. Morphological results indicated that the prepared films had smooth surfaces and high transparency. The addition of ionic liquids significantly reduced the crystallinity of CTA film and made it ductile. The Mechanical and thermal results showed that the ionic liquid anion has a significant effect on the properties of the film. CTA films plasticized with ionic liquids based on [PF6](-) were more flexible than the others, with an elongation of 18.22% instead of 1.97%. The climate ageing test, on the other hand, confirmed that the used ILs could indeed maintain the plasticized state during aging with a better stability of the hydrophobic IL in the polymer matrix compared to the hydrophilic IL. There are self-extinguishing with a final residue of about 97 wt%, allowing CTA films to be used for thermal insulation and fire protection, as well as packaging applications.

Automated summary

In this study, cellulose triacetate (CTA), a promising biodegradable polymer, was synthesized and plasticized with ionic liquids to produce flexible biocomposite films. The addition of ionic liquids significantly improved the mechanical properties and thermal stability of the films, making them ideal materials for thermal insulation, fire protection, and packaging applications.