Flame retardant cotton fabrics with anti-UV properties based on tea polyphenol-melamine-phenylphosphonic acid

Fabrication of flame-retardant and water-resistant nanopapers through electrostatic complexation of phosphorylated cellulose nanofibers and chitin nanocrystals

Biogenic, sustainable two-dimensional architectures, such as films and nanopapers, have garnered considerable interest because of their low carbon footprint, biodegradability, advanced optical/mechanical characteristics, and diverse potential applications. Here, bio-based nanopapers with tailored characteristics were engineered by the electrostatic complexation of oppositely charged colloidal phosphorylated cellulose nanofibers (P-CNFs) and deacetylated chitin nanocrystals (ChNCs). The electrostatic interaction between anionic P-CNFs and cationic ChNCs enhanced the stretchability and water stability of the nanopapers. Correspondingly, they exhibited a wet tensile strength of 17.7 MPa after 24 h of water immersion. Furthermore, the nanopapers exhibited good thermal stability and excellent self-extinguishing behavior, triggered by both phosphorous and nitrogen. These features make the nanopapers sustainable and promising structures for application in advanced fields, such as optoelectronics.

Facile Construction of Flame-Resistant and Thermal-Insulating Sodium Alginate Aerogel Incorporating N- and P-Elements

In this study, sodium alginate (SA) aerogel cross-linked with Ca2+ was selected as the basic skeleton to construct a lightweight, flame retardant, and thermal insulating composite aerogel via modification with melamine and phytic acid. The resulting aerogel, SA-1.0 MP, achieved a thermal conductivity as low as 0.0379 W/(m·K). Compared to pristine SA aerogel, SA-1.0 MP demonstrated improved fire resistance, evidenced by a substantial increase in the limiting oxygen index (LOI) from 21.5% to 48.8% and a V-0 rating in the UL-94 test. Furthermore, a synergistic mechanism was proposed to explain its remarkable flame-retardant capability.

Low temperature carbonization and synergistic flame retardancy of cotton fabric coated by phosphorus‑nitrogen flame retardants

To solve the problems of flammability and smoldering of cotton fabric, its flame-retardant finishing was executed with biomass wool keratin (WK) and cyclic phosphate ester (CPE) through the soaking and baking process. The synergistic mechanism of WK low-temperature melting and CPE catalytic dehydration prompted the formation of protective carbonization layer on cotton fabric surface, and this protective layer reduced its pyrolysis rate, inhibited the production of combustible materials and improved its flame retardancy. The results of synchronous thermal analysis indicate that the initial decomposition temperature of WK and CPE is lower than that of cotton fabric, and they precede the endothermic degradation before fabric main body. This effectively promotes the low-temperature carbonization of cotton fabric and inhibits its pyrolysis. The initial decomposition temperature of WK/CPE treated fabrics advances by 47.9 °C-97.8 °C, presenting significant low-temperature carbonization trend. Moreover, they form 3.0 %-20.0 % aromatic structural char before the pyrolysis of cotton cellulose due to the low-temperature dehydration and carbonization reactions. The damage length after vertical burning is only 4.0 cm for treated fabric with five layers, its after-flame and smoldering disappear, and its limiting oxygen index value increases to 28.7 %. This research provides an effective idea for the flammability and smoldering problems of cotton fabric.

Aromatic Biobased Polymeric Materials Using Plant Polyphenols as Sustainable Alternative Raw Materials: A Review

In the foreseeable future, the development of petroleum-based polymeric materials may be limited, owing to the gradual consumption of disposable resources and the increasing emphasis on environmental protection policies. Therefore, it is necessary to focus on introducing environmentally friendly renewable biobased materials as a substitute for petroleum-based feed stocks in the preparation of different types of industrially important polymers. Plant polyphenols, a kind of natural aromatic biomolecule, exist widely in some plant species. Benefiting from their special macromolecular structure, high reactivity, and broad abundance, plant polyphenols are potent candidates to replace the dwindling aromatic monomers derived from petroleum-based resources in synthesizing high-quality polymeric materials. In this review, the most related and innovative methods for elaborating novel polymeric materials from plant polyphenols are addressed. After a brief historical overview, the classification, structural characteristics, and reactivity of plant polyphenols are summarized in detail. In addition, some interesting and innovative works concerning the chemical modifications and polymerization techniques of plant polyphenols are also discussed. Importantly, the main chemical pathways to create plant polyphenol-based organic/organic-inorganic polymeric materials as well as their properties and possible applications are systematically described. We believe that this review could offer helpful references for designing multifunctional polyphenolic materials.

Improvement of fire safety for viscose fabrics based on phytic acid modified tea polyphenols complexed iron ions

In this work, a multifunctional finishing agent named as PATFe was prepared from phytic acid (PA), tea polyphenols (TP), and Fe3+. The optimum weight ratio of PA to TP was determined by exploring the effect on flame retardant and tensile properties of viscose fabrics. Then, the effects of different concentrations of iron ions on the flame retardant and tensile properties of viscose fabrics were further investigated, and finally, multifunctional viscose fabrics, PATFe-9, were prepared. The system was investigated to confer the multifunctional effects on the flame retardant, bacteriostatic, and UV-resistant properties of viscose fabrics under the condition of lower weight gains (about 6.0 wt%). The limiting oxygen index of PATFe-9 reached 33.7 % with a weight gain of 6.1 wt%, and PATFe-9 had an inhibition effect against Staphylococcus aureus, and the ultraviolet protection factor value reached 67. It is worth noting that the breaking force retention rate of this system reached 100 %, which greatly improves the scope of use and added value of viscose fabrics.

Effects of novel halogen-free flame-retardant binary additives on thermal stability, degradation kinetics and flame retardancy of cotton cellulose biomacromolecule

The principal component of cotton fibers is the cellulose biological macromolecule. However, its highly flammable nature has significantly constrained its utilization in fields where flame retardancy is essential. Herein, in this work, a highly effective binary composite flame retardant coating (APP/MEL-SWCNHs) with ammonium polyphosphate and modified single-walled carbon nanohorns (MEL-SWCNHs) was chemically attached to cotton fabric. With the add-on of 11.3 %, the treated cotton fabric (APP/MEL-SWCNHs)4 exhibited remarkable flame-retardant and self-extinguishing properties. Its LOI value increased to 23.7 ± 0.1 %, and the damage length was significantly reduced from 30.0 ± 0.1 % cm to 7.9 ± 0.1 % cm compared to the pristine cotton fabric. Despite partial carbonization, (APP/MEL-SWCNHs)4 preserved its original structure. Importantly, in the cone calorimeter test, both the pHRR and THR of (APP/MEL-SWCNHs)4 were drastically decreased by 71.8 % and 35.8 %, respectively. The APP/MEL-SWCNHs coating functioned as a flame retardant by inhibiting the emission of flammable volatiles, releasing non-flammable gases, and encouraging the formation of char layer during combustion. Significantly, thermal degradation kinetic analysis revealed that the third-order kinetic equation (O3) was found to have the strongest correlation with (APP/MEL-SWCNHs)4 in both air and N2 atmospheres. The higher activation energy (E) for (APP/MEL-SWCNHs)4 confirmed that incorporating MEL-SWCNHs improved the thermal stability of the char layer.

"One for two" strategy to construct an organic-inorganic polymer colloid for flame-retardant modification of flax fabric and rigid polyurethane foam

Polymeric materials such as fabric and foam have high flammability which limits their application in the field of fire protection. To this end, an organic-inorganic polymer colloid constructed from carboxymethyl chitosan and ammonium polyphosphate was used to improve the flame retardancy of flax fabric (FF) and rigid polyurethane foam (RPUF) based on a "one for two" strategy. The modification processes of FF and RPUF relied on pad-dry-cure method and UV-curing technology, respectively, and the modified FF and RPUF were severally designated as CMC/APP-FF and RFR-RPUF. Flame retardancy studies showed that CMC/APP-FF and RFR-RPUF exhibited limiting oxygen index values as high as 39.4 % and 42.6 %, respectively, and both achieved self-extinguishing behavior when external ignition source was removed. Thermogravimetric analysis and cone calorimetry test confirmed that CMC/APP-FF and RFR-RPUF had good charring ability and demonstrated reduced peak heat release rate values of 90.1 % and 10.8 %, respectively, distinct from before they were modified. In addition, condensed phase analysis showed that after burning, CMC/APP-FF became an integration char structure, whereas RFR-RPUF turned into a sandwiched char structure. In summary, the "one for two" strategy reported in this work provides a new insight into the economical fabrication of flame-retardant polymeric materials.

Bio-based phytic acid/amino acid complex coating for antimicrobial and flame-retardant cotton fabrics

Here, a novel multifunctional coating containing bio-based phytic acid (PA), L-glutamic acid (L-Glu), and trimesoyl chloride (TMC) is constructed by a simple soaking strategy, giving cotton fabrics excellent flame retardancy, washability, and antibacterial properties. The coating layer on the cotton surface was prepared via the electrostatic and hydrogen bonding between PA and L-Glu, accompanied by the interface polymerization between PA, L-Glu, and TMC. Among them, the limiting oxygen index value of the treated cotton fabrics (C2 and C2-TMC) was as high as 40 %. During the vertical flammability test, both C2 and C2-TMC cotton showed self-extinguished behavior with a short damaged length (≤50 mm). Remarkably, the LOI of C2-TMC sustained a high value (30 %) even after 300 laundering cycles, maintaining its self-extinguishing behavior in the vertical combustion test. Additionally, in the cone calorimetry test, peak heat release rate and total heat release of treated cotton were lower than control cotton. Surprisingly, after 30 or 60 laundering cycles, the C2-TMC cotton exhibited excellent antibacterial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans due to the continuous exposure of PA and L-Glu. Moreover, the coating layer on the cotton surface had little impact on the mechanical properties and feel of the fabric.

Facile Fabrication of Highly Efficient Chitosan-Based Multifunctional Coating for Cotton Fabrics with Excellent Flame-Retardant and Antibacterial Properties

Interest in the development of eco-friendly, sustainable, and convenient bio-based coatings to enhance flame retardancy and antibacterial properties in cotton fabrics is growing. In this work, chitosan was protonated at its amino groups using a method with a high atom economy using an equimolar amount of amino trimethylene phosphonic acid (ATMP), resulting in the fabrication of a single-component chitosan-based multifunctional coating (ATMP-CS), thereby avoiding any additional neutralization or purification steps. Cotton fabrics coated with various loads of ATMP-CS were prepared through a padding-drying-curing process. The morphology, thermal stability, mechanical properties, antibacterial properties, flame-retardant behavior, and flame-retardant mechanism of these fabrics were investigated. The coating exhibited excellent film-forming properties, and it imparted a uniform protective layer onto the surfaces of the cotton fabrics. When the load capacity reached 11.5%, the coated fabrics achieved a limiting oxygen index of 29.7% and successfully passed the VFT test. Moreover, the ATMP-CS coating demonstrated antibacterial rates against Escherichia coli and Staphylococcus aureus reaching 95.1% and 99.9%, respectively. This work presents a straightforward and gentle approach to fabricating colorless, environmentally friendly, and highly efficient fabric coatings that have potential applications in promoting the use of bio-based materials.

Preparation and properties of flame retardant and hydrophobic cotton fabrics based on poly-(dimethylsiloxane-co-diphenylsiloxane, dihydroxy terminated)/ammonia phytate

Applications for cotton fabrics with multifunctional qualities, such as flame retardancy, hydrophobicity, and anti-ultraviolet properties, are increasingly common and growing daily. The primary objective of this study is to investigate the preparation of flame retardant, hydrophobic, and ultraviolet (UV) protection cotton fabrics through the utilization of Poly-dimethylsiloxane-co-diphenylsiloxane, dihydroxy terminated (HTDMS) and ammonia phytate (AP). The flame retardancy, thermal stability, mechanical properties, anti-UV properties, air permeability and the hydrophobicity properties of coated cotton fabrics were evaluated. The results indicated that the HTDMS/AP coating was successfully deposited on the surface of cotton fabrics. The damaged length of Cotton/HTDMS/AP was 4.7 cm, and the limiting oxygen index reached 31.5 %. The thermogravimetric analysis revealed that the char residues in the high-temperature range were increased. Furthermore, cone calorimetry results indicated that after the HTDMS/AP coating, the peak heat release rate, total heat release, and total smoke production values decreased by 88.7 %, 51.2 %, and 98.4 %, respectively. Moreover, the deposition of HTDMS/AP provided cotton fabrics with hydrophobicity with a water contact angle of over 130°, while Cotton/HTDMS/AP maintained their air permeability, and enhanced the breaking force compared with those of Cotton/AP. Such desirable qualities make HTDMS/AP a meaningful coating for producing multifunctional cotton fabrics.

A molecularly engineered fully bio-derived phosphorylated furan-based flame retardant for biomass-based fabrics

With the increasing awareness of environmental protection, the demand for eco-friendly bio-derived flame-retardant for textiles has received increasing attention. In this work, a fully bio-derived phosphorylated furan-based flame retardant (FAP) was synthesized by the Schiff reaction of furan-based compounds (furfural and furfurylamine). To evaluate the application scope and flame retardant efficiency of FAP, cotton fabrics and PLA nonwovens were selected as biomass-based representatives of natural fiber materials and synthetic fiber materials, respectively. Significantly, based on the composition of furan ring, phosphorus and nitrogen containing components of FAP, excellent charring and flame retardant properties of coated cotton fabrics and PLA nonwovens can be expected. TGA results showed that the residual char of C-FAP-3 and P-FAP-3 were 39.7% (increased by 267.6%) and 16.7% (increased by 215.1%), respectively, higher than those of control cotton (10.8%) and PLA nonwoven (5.3%). Cone test results exhibited that the peak heat release rate (PHRR) and total heat release (THR) values of C-FAP-3 were sharply decreased by 69.4% and 37.8%, respectively. P-FAP-3 also displayed a significant reduction in PHRR, implying high flame retardancy of C-FAP-3 and P-FAP-3. Notably, through the weight gains of FAP coating on cotton and PLA as well as the final LOI and VBT results of the flame retardant treated fabrics, it can be preliminarily inferred that control cotton fabrics are more likely to achieve better flame retardant effects than PLA. Additionally, the facile synthetic strategy of fully bio-derived flame retardants is expected to promote the development of green flame retardant strategies for high-performance textiles.

A P/N flame retardant for polyester-cotton fabrics: Flame retardancy, mechanical properties and antibacterial property

A phosphorus‑nitrogen synergistic flame retardant (named POI) was obtained by the chemical reaction between phenylphosphonic acid (PPOA) and polyethyleneimine (PEI), and used to give the flame retardancy of PTCO. The effects of PPOA and POI on various properties of PTCO were investigated. PPOA obviously improved the flame retardancy of PTCO/PPOA, while the breaking force of PTCO/PPOA was greatly reduced. However, the introduction of PEI made the surface of fabrics smoother. PTCO/POI had better flame retardancy than PTCO/PPOA did, and the limiting oxygen index value of PTCO/POI reached to 29.8 %. POI had a good effect on reducing the Rmax of both cotton and polyester components. The phosphoric acid groups in POI can promote the dehydration and carbonization reactions of PTCO, which protects the inner fabrics, and POI can release incombustible gases such as NH3 and N2 during burning, which can dilute the oxygen concentration. The flame-retardant mechanism of PTCO/POI was mainly the condensed phase. At the same time, there were no changes in whiteness and mechanical properties compared with those of PTCO, and it also had antibacterial property. This work provides a simple and effective method to prepare flame-retardant and antibacterial PTCO.

Bio-based alginate and Si-, P- and N-containing compounds cooperate toward flame-retardant modification of polyester fabrics

Imparting flame retardancy to polyester fabrics is still a pressing issue for the textile industry. To this end, a composite coating was developed by phosphite, pentamethyldisiloxane, urea and sodium alginate, and then applied together with calcium chloride to prepare flame-retardant polyester fabrics. The optimized polyester fabrics named PF-HUSC exhibited a rough surface with P, Si, N and Ca element distributions, as observed by scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDX). Flame retardancy evaluations showed that the damaged length of PF-HUSC with a limiting oxygen index (LOI) value of 35.3 ± 0.3 % was reduced from the contrastive 17.6 ± 0.4 cm to 4.6 ± 0.2 cm after vertical burning test. Thermogravimetric (TG) test confirmed that PF-HUSC retained a char residue as high as 35.1 % at 700 °C. Cone calorimetry test displayed that the total heat release (THR) and total smoke production (TSP) values of PF-HUSC were reduced to 3.1 MJ/m2 and 1.1 m2, respectively, as compared to those of pure polyester fabrics. More importantly, PF-HUSC still exhibited higher LOI value than that of pure polyester fabrics after 25 washing cycles. Hence, the coating scheme is considered as a new method to expand the preparation of flame-retardant polyester fabrics.

Flame retardant, heat insulating and hydrophobic chitosan-derived aerogels for the clean-up of hazardous chemicals

Leakage of hazardous chemicals often causes significant casualties, enormous economic losses, and negative social benefits. Presently, fire rescue personnel lack efficient and eco-friendly disposal materials for hazardous chemical leakage accidents. In this study, chitosan (CS) aerogels with excellent flame-retardant performance were prepared via cross-linking by two phosphorus-containing vanillin-based compounds (DV and TV). The as-prepared chitosan aerogels were lightweight and porous. The introduction of DV and TV greatly enhanced the residual char yields of CS at 700 °C and the flame-retardant performance of chitosan aerogels. TCS-5.0 possessed the best flame-retardant performance, indicating that TV was more effective than DV in enhancing the flame-retardant performance of chitosan aerogels. The greatly improved flame-retardant properties could be attributed to TV effectively promoting the residual char formation of chitosan aerogels and reducing the formation of combustible gas phase products. To improve the hydrophobicity of chitosan aerogels, TCS-5.0 was treated with solution immersion to load siloxane molecules on its surface. The water contact angle of HTCS-5.0 was 136.1°. HTCS-5.0 had a high oil absorption multiplicity, absorbing up to 31 times its own weight of chloroform. HTCS-5.0 could continuously absorb organic solvents on the water surface with the assistance of a vacuum pump, indicating that HTCS-5.0 could be used for the clean-up of hazardous chemical leakage accidents.

Durable multifunctional cotton fabric with superior biocidal efficacy and flame retardancy based on an ammonium phosphate N-halamine

Multifunctional textiles have become the mainstreams along with development of textile industry and the increased need of public. But a facile fabrication method with well-balance of multiple functions is still a challenge. In this work, an ammonium salt of tris(methylphosphonate)aminomethane (TAMPU), which can directly react with cellulose molecules and transform to N-halamine antibacterial structure, was easily synthesized and used to achieve multifunctional cotton fabric. As a result, the modified cotton fabric of 15.8 % weight gain exhibited excellent fire resistance with LOI value of 33.8 % and self-extinguishing behavior. Due to the good char-forming capacity of TAMPU, strong heat suppression was achieved and the peak of heat release rate (PHRR) and total heat release (THR) were decreased by 87.6 % and 60.8 %, respectively. Besides, the modified samples presented outstanding bactericidal effects, and all of S. aureus and E. coli could be inactivated within 5 min without dissolution phenomenon. Furthermore, the TAMPU-modified cotton fabric owned good washing durability and LOI value was remained at 29.8 % after 50 washing cycles. This TAMPU multifunctional modification had slight influence on the mechanical property and air permeability of cotton fabric. Thus, this work provides a convenient and friendly way to fabricate multifunctional flame-retardant and antibacterial cotton fabric.

An eco-friendly, highly efficient, and transparent coating derived from guar gum and citric acid for flame retardant treatment of cotton fabrics

A highly efficient, bio-ecofriendly, and transparent flame retardant (FR) for cotton fabric was developed and deposited onto the cellulose skeletal structure of cotton fabric through a one-pot sol-gel process. The flame retardant functional coating is composed of ammonium polyphosphate (APP), guar gum (GG), citric acid (CA), and a negligible amount of catalyst. Cotton fabrics were impregnated with different concentrations of ammonium polyphosphate and guar gum, with citric acid as a crosslinking agent. The overall crosslinking and grafting process was proven by FTIR and XPS. Based on the results, the designed coating exhibits over 90 % transmittance in the visible region. A 15 g/m2 flame-retardant coating induces excellent flame retardant efficiency at ultra-low flame-retardant concentrations of less than 6.25 wt%. Only a 5.25 wt% flame retardant concentration demonstrated condensed phase action, which resulted in 58.5 % and 73.6 % reductions in the pHRR and THR, respectively. Moreover, the limiting oxygen index (LOI) value showed a 74 % increase. The mechanical performance of FR coated cotton fibers was slightly reduced.