Novel and eco-friendly flame-retardant cotton fabrics with lignosulfonate and chitosan through LbL: Flame retardancy, smoke suppression and flame-retardant mechanism

• Published in: Polymer degradation and stability Vol. 181; p. 109302
• Main Authors: Li, Ping, Liu, Chang, Xu, Ying-Jun, Jiang, Zhi-Ming, Liu, Yun, Zhu, Ping
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.11.2020; Elsevier BV
• Subjects: Bio-based materials; Biological materials; Chitosan; Cotton fabrics; Cotton fibers; Enthalpy; Fabrics; Flame retardancy; Flame retardants; Flammability; heat; Heat conductivity; Heat release rate; Heat transfer; Intumescent flame-retardant system; Lignosulfonate; Lignosulfonates; oxygen; pollution; polymers; Residues; Scanning electron microscopy; Smoke; Studies; Thermal degradation; Thermogravimetric analysis; thermogravimetry; Flame retardancy; Intumescent flame-retardant system; Cotton fabrics; Lignosulfonate; Bio-based materials
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2020.109302

Bio-based materials have been noticed for the continuous environmental pollution and resource shortage. In this paper, lignosulfonate (LS) and chitosan (CS) were selected to be flame-retardants. In the vertical flame test (VFT), LS/cotton-17.1 wt%, CS/LS/cotton-17.0 wt%, and CS/LS/cotton-25.2 wt% obtained lower afterflame times than that of uncoated cotton fabrics, while LS/cotton-17.1 wt% had serious afterglow time of 70 s. However, the afterglow time of CS/LS/cotton-25.2 wt% was 11 s, which decreased owing to the increased amount of CS. LS/cotton-17.1 wt%, CS/LS/cotton-17.0 wt%, and CS/LS/cotton-25.2 wt% presented limiting oxygen index values of 24.7%, 25.0%, and 26.0%, respectively. The scanning electron microscope images of char residues after the VFT showed that CS and LS formed an intumescent flame-retardant system, and cotton fibers remained intact structure. Meanwhile, the results of thermogravimetric analysis suggested that flame-retardant cotton fabrics can generate stable char residues. In N2 atmosphere, CS/LS/cotton-25.2 wt% generated 27.1% stable char residues. Moreover, the addition of CS/LS decreased the heat release rate and total heat release values and this system performed well in smoke suppression. The flame-retardant mechanism of the system might belong to gas-phased because more non-combustible products were generated in the thermal degradation process. •Lignosulfonate and chitosan were chosen to act as flame retardant.•CS/LS can form effective intumescent flame-retardant system.•The addition of CS can reduce the afterglow time of LS/cotton.•CS/LS/cotton presents well smoke suppression performance.