Facile Strategy to Fabricate the Flame Retardant Polyamide 66 Fabric Modified with an Inorganic-Organic Hybrid Structure

Superhydrophobic, Highly Conductive, and Trilayered Fabric with Connected Carbon Nanotubes for Energy-Efficient Electrical Heating

Current electrically heated fabrics provide heat in cold climates, suffer from abundant wasted radiant heat energy to the external environment, and are prone to damage by water. Thus, constructing energy-efficient and superhydrophobic conductive fabrics is in high demand. Therefore, we propose an effective and facile methodology to prepare a superhydrophobic, highly conductive, and trilayered fabric with a connected carbon nanotube (CNT) layer and a titanium dioxide (TiO2) nanoparticle heat-reflecting layer. We construct polyamide/fluorinated polyurethane (PA/FPU) nanofibrous membranes via first electrospinning, then performing blade-coating with the polyurethane (PU) solution with CNTs, and finally fabricating FPU/TiO2 nanoparticles via electrospraying. This strategy causes CNTs to be connected to form a conductive layer and enables TiO2 nanoparticles to be bound together to form a porous, heat-reflecting layer. As a consequence, the as-prepared membranes demonstrate high conductivity with an electrical conductivity of 63 S/m, exhibit rapid electric-heating capacity, and exhibit energy-efficient asymmetrical heating behavior, i.e., the heating temperature of the PA/FPU nanofibrous layer reaches more than 83 °C within 90 s at 24 V, while the heating temperature of the FPU/TiO2 layer only reaches 53 °C, as well as prominent superhydrophobicity with a water contact angle of 156°, indicating promising utility for the next generation of electrical heating textiles.

Improving the hygroscopicity and flame retardancy of polyamide 6 fabrics by surface coating with β-FeOOH and sulfamic acid

The combustion of polyamide 6 (PA6) fabrics releases toxic smoke, which will pollute the environment and threaten human life and health. Herein, a novel eco-friendly flame-retardant coating was constructed and applied to PA6 fabrics. Needle-like β-FeOOH with a high surface area was firstly constructed onto the surface of PA6 fabrics by the hydrolysis of Fe³⁺, sulfamic acid (SA) was then introduced by a facile dipping and nipping method. The growth of β-FeOOH also endowed the PA6 fabrics with certain hydrophilicity and moisture permeability, resulting in improved comfortability. The limiting oxygen index (LOI) of the prepared PA6/Fe/6SA sample was increased to 27.2% from 18.5% of control PA6 sample, and the damaged length was reduced to only 6.0 cm from 12.0 cm of control PA6 sample. Meanwhile, the melt dripping was also eliminated. The heat release rate and total heat release values of the PA6/Fe/6SA sample were decreased to 318.5 kW/m² and 17.0 MJ/m², respectively, compared with those of control PA6 (494.7 kW/m² and 21.4 MJ/m²). The analysis results indicated that nonflammable gases diluted flammable gases. The observation of char residues demonstrated that the stable char layer was formed, which effectively inhibited the transfer of heat and oxygen. The organic solvent-free coating does not contain any conventional halogens/phosphorus elements, which provides a useful methodology to produce environmentally friendly flame-retardant fabrics.

Bio-based phytic acid@polyurushiol‑titanium complex coated cotton fabrics with durable flame retardancy for oil-water separation

Bio-based hydrophobic coating modified cotton fabrics with durable flame retardancy are of high interest in the application of oil-water separation for not only avoiding the use of hazardous substances but also improving the fire safety during use. Herein, phytic acid@Polyurushiol‑titanium complex coated cotton fabric was developed using the facile dip-coating method involving the sequential immersion in the solution of poly(ethyleneimine), phytic acid, titanium oxide, and urushiol. The underlying coating accommodated abundance of phytic acid, which imparted excellent flame retardancy to cotton fabric, and the top coating composed of the polyurushiol‑titanium complex endowed cotton fabric with high hydrophobicity that the water contact angle (WCA) was up to 149.8°. The hydrophobicity also guaranteed effective protection of the underlying phytic acid against chemical solvents and abrasion. Besides, the hydrophobic coating allowed cotton fabric for good self-cleaning and effective oil-water separation. Therefore, the preparation of phytic acid@polyurushiol‑titanium complex coated cotton fabric offers a promising approach to construct durable biomass-coated cellulose-based fabric with multifunctionality.

Synergistic Effects of Diatoms on Intumescent Flame Retardant High Impact Polystyrene System

In this work, aiming to improve the flame retardancy performance of high impact polystyrene (HIPS), HIPS compounds were synthesized with the addition of intumescent flame retardant (IFR: mass ratio of APP and PER was 3:1) and diatoms into HIPS matrix by melt blending method. It was found the IFR/diatoms system exhibited high flame retardant efficiency and catalytic carbonization effect to HIPS matrix in the burning process. The LOI value of HIPS-2 compound with the addition of 28 wt% IFR and 2 wt% diatoms was increased to 29.0% and passed V-0 rating. The value of PHRR for HIPS-2 compound is about 460.58 kW/m² compared with 937.22 kW/m² of pure HIPS and the value of THR for HIPS-2 compound is about 32.9 MJ/m² compared with 62.7 MJ/m² of pure HIPS, suggesting that the addition of IFR/diatoms system can decrease the values of PHRR and THR, which shows the synergistic effect between IFR and diatoms on reducing heat release. The 21.9% reduction in Av-EHC and 41.4% reduction in TSP seen on introducing an IFR/diatoms system indicates effective smoke suppression, which potentially would significantly reduce the death rate in real fire accidents. The TG-IR results indicated that the IFR/diatoms flame retardant system functioned in the gas phase to suppress the flame. The SEM images showed the char residue produced was more compact and continuous, which suggests that the IFR/diatoms flame retardant system exhibits barrier and catalytic effects to block heat transferring and promote char forming. The tensile strength and impact strength of HIPS-2 compound were 22.95 MPa and 2.63 KJ/m², respectively. The tensile strength and impact strength were increased by 34.13% and 19.55% compared with that of pure HIPS.