Preparation of phosphorus‐containing and nitrogen‐containing durable flame retardant polyacrylonitrile fabric via surface chemical modification

Abstract

Summary Ultraviolet‐induced photografting polymerization combined with surface modification was developed to prepare durable flame retardant polyacrylonitrile (PAN) fabric. First, acrylic acid (AA) was grafted onto PAN fabric (PAN‐g‐PAA) through ultraviolet‐induced photograft polymerization. Then, PAN‐g‐PAA was modified sequentially by acylation, ammonization, and phosphorylation to obtain acylated PAN‐g‐PAA, ammoniated Cl‐PAN‐g‐PAA, and fire retardant PAN fabric, respectively. The influence of grafting time, concentration of acrylic acid, and initiator on the grafting percentage was studied in detail. Fourier transform infrared spectrometer, X‐ray diffraction, and scanning electron microscopy confirm the successful grafting of AA. The thermal properties of the fabrics were investigated by thermogravimetric analysis and differential scanning calorimetry. Thermal analysis indicates that FR‐PAN has good thermal stability at higher temperature and the char residue is about 41 wt% at 800°C. The limiting oxygen index value of the fire retardant fabrics can achieve 28.1 vol% and is still 27.3 vol% after 20 cycles washing, showing good durability.

Advanced Flame‐Retardant Methods for Polymeric Materials

“…Meanwhile, UV curing technology has been used in the construction of durable coatings, due to the promotion of stable covalent bonds between the coating and the substrates (fabrics, woods, etc.). [ 210 ] As shown in Figure 6b, the monomers or oligomers should have both P−N flame‐retardant groups and unsaturated bonds, which can be further chemically crosslinked with the active groups (−OH, −NH 2 , etc.) of the substrates under the action of the initiator and UV.…”

Fabrication of Chitosan-Based Intumescent Flame Retardant Coating for Improving Flame Retardancy of Polyacrylonitrile Fabric

“…As for the PAN-g-GMA-g-CS sample, the appeared absorption peaks at around 1066 cm −1 and 3391 cm −1 attributing to the C-N and N-H, which indicate that CS was successfully grafted onto the PAN-g-GMA fabric. As for the spectra of FR-PAN, the bands at 1047 cm −1 and 974 cm −1 attributed to the characteristic peaks of P=O and P-O-C groups confirm the phosphorylation of PAN-g-GMA-g-CS sample [7,8,9,10]. Meanwhile, a wide peak appeared at around 3327 cm −1 ascribing to N-H group owing to the presence of NH 4+ in the flame-retardant PAN fabric, as shown in Scheme 1.…”

“…In our previous work, we used UV-induced photo-grafting technology to impart PAN fabric flame retardancy. For example, acrylic acid (AA) was UV-grafted onto PAN fabric followed by chemical modification to obtain fire-retardant PAN fabric [7]. The LOI value of the treated fabric after 20 cycles of washing was 27.3%, thus showing good flame-retardant durability.…”

High-performance polyacrylonitrile-based pre-oxidized fibers fabricated through strategy with chemical pretreatment, layer-by-layer assembly, and stabilization techniques

“…The LOI value of the fire-retardant fabrics could reach up to 28.1%. 20 Zhang et al modified PAN fabrics with hydroxylamine hydrochloride (HA) to prepare amidoxime PAN fabrics (A-PAN) followed by phosphorylation with phosphoric acid (PA) to obtain flame-retardant PAN fabrics (P-A-PAN). The fabricated P-A-PAN demonstrated excellent thermal stability and high LOI value of 34.1%.…”