Kim, Jongho You, Nam-Ho Ku, Bon-Cheol 2024-01-19T16:03:46Z 2024-01-19T16:03:46Z 2021-09-02 2020-11-07 1759-9954 https://pubs.kist.re.kr/handle/201004/117853 Polyacrylonitrile (PAN) is utilized as a precursor for the production of high-performance flame retarding fibers and is also widely used for clothing fibers. Herein, we report the flame retarding properties of catechol-containing PAN copolymers. The comonomer, dihydroxy styrene (DHS), was prepared from bio-derived caffeic acid (CA), which is a key intermediate in the biosynthesis of lignin. P(AN-co-DHS) and P(AN-co-CA) were synthesized by free radical polymerization. The effect of the comonomer structure on the stabilization of PAN copolymers was studied by differential scanning calorimetry, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The catechol and acid groups of P(AN-co-DHS) and P(AN-co-CA) are effective at lowering the activation energy (E-a) for cyclization of the AN through an ionic mechanism. In CA copolymers, the acid-protected poly(acrylonitrile-co-methyl caffeate) (P(AN-co-MCA)) was found to be the most efficient in terms of E-a, the extent of reaction, and char fraction. The microscale combustion calorimetric analysis after thermal treatment (300 degrees C, 3 min) showed that the limiting oxygen index and heat release capacity of the P(AN-co-MCA(3)) fiber were approximately 45% with V-0 of UL rating (superior to Nomex (R)) and 63 J g(-1) K-1, respectively. This research demonstrates a simple, sustainable methodology for the production of environmentally friendly and high-performance flame retardants. English ROYAL SOC CHEMISTRY STABILIZATION REACTIONS FIBERS ANTIOXIDANT FLAMMABILITY DEGRADATION FABRICATION RESISTANCE MECHANISM POLYMERS CATECHOL Highly efficient halogen-free flame retardants of thermally-oxidized polyacrylonitrile copolymers containing bio-derived caffeic acid derivatives Article 10.1039/d0py00854k 1 POLYMER CHEMISTRY, v.11, no.41, pp.6658 - 6669 POLYMER CHEMISTRY 11 41 6658 6669 scie scopus 000583959300010 2-s2.0-85095121770 Polymer Science Polymer Science Article STABILIZATION REACTIONS FIBERS ANTIOXIDANT FLAMMABILITY DEGRADATION FABRICATION RESISTANCE MECHANISM POLYMERS CATECHOL halogen-free flame retardants caffeic acid polyacrylonitrile