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In this study, novel durable flame-retardant lyocell fibres were designed by the addition of phosphorylated cellulose and physical blending of montmorillonite (MTT) within the fibres. The influences of phosphorylation and MTT blending on the flame retardancy of lyocell fibres were investigated. Additionally, the synergistic effects of the two flame retardant methods were also discussed. Furthermore, phosphorylated cellulose and MTT-filled lyocell fibres were prepared, and their flame retardancy was measured. Phosphorylation (limiting oxygen index (LOI) > 28%) was found to improve the flame retardancy of the lyocell fibres; nevertheless, excessive phosphorylation decreased the crystallinity of the cellulose and decreased the mechanical strength of the fibres. Montmorillonite was added to the lyocell fibres to achieve durable flame retardancy, whereas the LOI was less than 24%. Interestingly, lyocell fibres with LOIs greater than 28% and strengths greater than 2.0 cN/dtex could be obtained from the phosphorylated cellulose with MTT filling. The thermogravimetric (TG) and TG-infrared (TG-IR) experimental results showed that MTT played a role in the condensed-phase flame retardancy, while phosphorylated cellulose played a role in the gas-phase and condensed-phase flame retardancy. The Raman test results showed that the combination of MTT and phosphorylated cellulose enhanced the graphitization degree of the residue char. In our study, a novel flame-retardant method for the preparation of lyocell fibres with permanent flame retardancy and high tensile strength was developed; moreover, our results contribute to the development of industrial-grade fabrication of new flame-retardant fibre materials. [ABSTRACT FROM AUTHOR]

In order to explore the performance advantages and application areas of Lyocell filament nonwovens, the performance differences between Lyocell filament nonwoven materials (homemade) and commercially available cellulosic nonwoven materials were comparatively analyzed, Lyocell filament nonwovens were compared with Lyocell staple fiber, viscose staple fiber and copper ammonia filament from the aspects of micro-morphology, crystallinity, water absorption, air permeability, softness and strength. The results show that the crystallinity and strength of Lyocell nonwoven materials are better than that off varicose and copper-ammonia nonwoven materials due to the direct spinning into a web process, and the fibre breakage of Lyocell filament nonwoven materials is less, the inter-fibre entanglement is better, and the rate of chip-out is lower than that of viscose staple fibre and Lyocell staple fibre nonwoven materials due to the direct spinning into a net process. [ABSTRACT FROM AUTHOR]

In this paper, the hydrolysis process of Dichlorohydroxytriazine (NHDT) under alkaline conditions are studied. A qualitative and quantitative method for the determination of HNDT and its hydrolysis products are established, which further clarified the hydrolysis mechanism of NHDT. Under alkaline conditions, the hydrolysis products are mainly compound 4, compound 6 and chloride (Cl−). The hydrolysis rate of NHDT at different NaOH concentration and temperature is studied. This research can be used to guide the high efficiency preparation of low fibrillation Lyocell fiber. According to the quantitative detection of wet abrasion numbers and the qualitative analysis of the fiber by SEM after slapping, it is concluded that the low fibrillation Lyocell fiber is less prone to fibrillation under the combined action of wet state and mechanical force. Due to hydrolysis of the unreacted second chlorine resulting in harmful products on the low fibrillation Lyocell fiber, the fibrillation propensity increased with the increase of storage time. The mechanical properties of low fibrillation Lyocell fiber prepared under different fiber states are studied. The tensile breaking strength of low fibrillation Lyocell fiber prepared in the form of sequentially arranged fiber bundles are better, which is closely related to the fiber surface. [ABSTRACT FROM AUTHOR]

A biomass vitamin B6-based flame retardant, ammonium salt of pyridoxine phosphoric ester acid (ASPPEA) was synthesized and used for modification of lyocell fibers. FTIR, XPS and EDX analyses indicated that lyocell fibers had been successfully grafted with ASPPEA. The ASPPEA improved the char-forming ability, as evidenced by the increase of the char residue (51 wt%) of ASPPEA-treated lyocell fibers. The limiting oxygen index (LOI) value of ASPPEA-treated lyocell fabrics increased up to 48.3%. After 450 min washing, the LOI value remained 30.8%, thus demonstrating the flame retardant durability. The total heat release of ASPPEA-treated lyocell fabrics decreased by 82.5%. During the pyrolysis, the ASPPEA decomposed to produce acidic substances which promoted the dehydration and char formation of lyocell fibers, thus blocked the exchange of heat and flammable gas. This research proposes a novel application of vitamin B6 to impart lyocell fibers with flame retardancy. [ABSTRACT FROM AUTHOR]

Functional materials such as fireproof fabrics or fibers usually destroy mechanical strength due to the introduction of flame retardant. In this work, ionic liquid 1,3-dimethyl imidazolium methyl phosphite, one solvent and modifier, was employed to fabricate phosphorylated cellulose. As a cellulose-based derivative, phosphorylated cellulose displayed good compatibility and dispersity in cellulose spinning which was proved by the uniform cellulose spinning dope and compact fiber structure. Owing to the special and similar structure, phosphorylated cellulose interaction with cellulose unit was conducive to enhancing mechanical strength of lyocell fiber. The flame retardant lyocell fibers (FRLF) with phosphorus content (<1 at %) exhibited excellent flame retardancy. The value of peak of heat release rate (PHRR) declined by 50.9 % compared with pure lyocell fibers (LF), as micro-combustion calorimetry measurement estimated. Meanwhile, the breaking strength of FRLF increased by 6.44 % compared with that of LF. In brief, this work balanced the flame retardancy and mechanical properties of lyocell fibers via one-step synthesizing fire retardant cellulose-based filler based on the structural similarity between matrix and flame retardant. [Display omitted] • Ionic liquid as green modifier was used to modify cellulose powder by one-step. • Fire retardant cellulose-based filler was successfully synthesized. • Phosphorylated cellulose, fire retardant filler, was introduced to lyocell fibers. • Flame retardancy and mechanical strength of lyocell fibers achieved a balance. [ABSTRACT FROM AUTHOR]