Flame Retardancy Of Composites Research Articles

Flame retardancy, thermal, and mechanical properties of flame retardant PA6/SGF and PPS/PA6/SGF composites

AbstractFlame retardant polyamide 6/short glass fiber (FR PA6/SGF) and polyphenylene sulfide/PA6/SGF (FR PPS/PA6/SGF) composites were prepared by melt extrusion blending using aluminum diethylphosphinate (ADPP) as flame retardant. The thermogravimetric analysis (TGA) indicated that the flame retardant composites showed good thermal degradation with increasing ADPP loading. Flame retardancy mechanisms were studied by analyzing the residue chars. ADPP provided better flame inhibition, promoted formation of carbonaceous char, and improved thermal stability of PA6/SGF. Meanwhile, due to the self‐extinguishing performance of PPS, the flame retardancy of PPS/PA6/SGF was greatly affected by only 3.0 wt% of ADPP. With increasing ADPP content, both storage and loss moduli of FR PA6/SGF and FR PPS/PA6/SGF were increased accompanied with a slight increase of tan δ peak as compared to PA6/SGF and PPS/PA6/SGF, respectively. Besides, notched impact strengths of FR PA6/SGF‐10.0 and FR PPS/PA6/SGF‐10.0 increased by 69% and 5%, while tensile strengths decreased by approximately 5% and 32%, as compared to PA6/SGF and PPS/PA6/SGF, respectively. It demonstrates that ADPP and PPS components are efficient inorganic–organic hybrid flame retardant system. This provides a novel and innovative method for preparing halogen‐free flame retardant reinforced polyamide composites.

Cobalt-doped iron-based Prussian blue analogue cubes anchored to phosphorus‑nitrogen-covered BN surfaces for enhancing the flame retardancy of epoxy coatings

Prussian blue analogue (PBA) is considered to be a very promising inorganic nano-flame retardant material due to its structure enriched with transition metal elements. Here, hexachlorocyclotriphosphazene (HCCP) and p-phenylenediamine (p-PDA) were first loaded onto the boron nitride surface (BN/PCP) via a polymerization reaction to impart richer flame retardant characteristics. Then, Co-Fe-based PBA nanoparticles were homogeneously anchored on the BN/PCP surface to obtain the BN/PCP@PBA hierarchical nano-flame retardant. It is worth mentioning that this novel composite flame retardant effectively combined the superior barrier properties of BN, fire retardancy of N, P elements and the accelerated carbon conversion effect of Co-Fe/PBA. The test results showed that the loading of PCP on the BN surface could effectively improve the thermal insulation performance of EP, while Co-Fe/PBA had good catalytic carbon formation effect at high temperature. Specifically, the backside of the BN/PCP@PBA filled EP sample displayed the lowest temperature during flame attack (164.1 °C) compared to the other specimens, proving its best thermal insulation. The BN/PCP@PBA/EP obtained the maximum expansion height and expansion rate values (27.6 mm and 21.07) in the furnace chamber experiments, which are crucial for its fire resistance. In addition, BN/PCP@PBA/EP retained the highest residual char (32.6 %) and achieved the lowest smoke density rating (36.9 %), demonstrating its high carbon conversion and fume suppression. Carbon residue analysis confirmed that the char layer of BN/PCP@PBA/EP was more complete and the metal oxides were uniformly embedded in the carbon residue skeleton, which ensured good flame protection for the substrate.

Effect of H<sub>3</sub>PO<sub>4</sub> and Phenol Additives on Gel Formation in Silica Fire Retardant Coatings for Building Materials

Increasing the fire resistance of wooden building structures is quite effectively ensured thanks to the development of fire-fighting compositions with aromatic components that contribute to the formation of a carbonized layer on the surface of the material during combustion. It is also known about the mutual positive influence of benzene fragments and phosphate-containing compounds on the fire-resistant characteristics of wood. The paper considers the possibility of complex use of phenol and orthophosphate acid to improve the flame retardant properties of SiO2-based coatings. The effect of modifying additives on the rheological properties of silicic acid sols was determined. Based on the results of IR spectroscopy, the influence of components on the nature of polycondensation in experimental SiO2 sols was evaluated. It is shown that the use of orthophosphate acid as a modifier leads to the initiation of predominantly linear polycondensation in experimental sols. It was established that small additions of phenol practically do not affect the course of polycondensation in experimental sols. Increasing the phenol content to 0.5% showed an effect on gel formation due to the possible addition of phenol to the skeletal silanol groups by the donor-acceptor mechanism, which makes it possible to have a synergistic effect of the complex additive of orthophosphate acid and phenol on the properties of the silica-containing flame retardant composition.

In-suit cemented strategy enables intumescent flame retardant transition from hyper-hydrophilic to hydrophobic and aggregation flame retardant effect simultaneously in polypropylene

To meet the stringent requirements of specific high-end manufacturing applications involving flame retardant polypropylene (PP) materials, it's imperative to overcome the inherent superhydrophilicity of intumescent flame retardants (IFR) while simultaneously further enhancing flame retardant efficiency. In addressing this challenge, novel in-situ cemented MVC-IFR microparticles characterized by a microparticle-aggregation effect and hydrophobic structure were successfully synthesized. The micro-aggregated MVC-IFR particles not only bolstered the hydrophobicity and charring flame retardancy of PP composites compared to conventional IFR but also exhibited superior resistance to water erosion. The water contact angle (WCA) of 3MVC-22IFR reached an impressive 159°, whereas the WCA of IFR stood at 0°. Moreover, when MVC-IFR and IFR were incorporated into PP, 3MVC-22IFR/PP displayed a WCA of 108° which was a hydrophobic composite, while 25IFR/PP exhibited a WCA of 81° which was a hydrophilic composite. Notably, the hydrophobic MVC-IFR showcased greater resistance to water exposure than hydrophilic IFR, thereby maintaining its flame retardant efficacy in practical applications. Furthermore, MVC-IFR microparticles with aggregation of acid, carbon, and gas sources, facilitated the charring reactions of different components, thereby enhancing its charring flame retardant effect in PP. Remarkably, 1MVC-24/PP not only attained a UL 94V-0 rating but also achieved a glow wire flammability index (GWFI) of >960 °C, a glow wire ignition temperature (GWIT) of 850 °C, and an LOI value of 28.7 %. In contrast, 25IFR/PP failed to secure a UL 94 rating and exhibited lower GWIT and LOI values. Crucially, the peak heat release rate and total smoke release of 1MVC-24IFR/PP were markedly reduced by 76 % and 41 %, respectively, compared with those of neat PP. In summary, this study presented a novel design concept and rules for flame retardant morphology, to find a way for the development of polyolefin materials boasting both high hydrophobicity and superior flame retardancy.

Fabrication of a 2D/2D g-C3N4@ZnTDA nanosheets catalyst for highly efficient degradation of 2,4-dibromophenol and improved flame retardancy of polyurethane foam

High charge separation and transfer efficiency are considered as key factors of photocatalysts in wastewater treatment applications. In this work, a high performance photocatalyst g-C3N4@ZnTDA was designed and applied through a facile solvothermal strategy. The microstructural, morphological, physicochemical, and photoelectrochemical properties of g-C3N4@ZnTDA were fully characterized. The photocatalytic activity of g-C3N4@ZnTDA nanoparticles under visible light source in degrading the 2,4-dibromophenol(2,4-dB) contaminants was also successfully studied. Additionally, the g-C3N4@ZnTDA composite demonstrates easy operation and good regeneration ability, making it highly promising for the efficient removal of phenolic pollutants from wastewater. Besides, a novel reutilization method for used catalyst as flame retardant and for PU foams was successfully testified. The MCN-3 as a fire-safety coating could reduce the heat release and improve flame retardancy of PU composites. This work opens a new window for valuable inspiration and structural design of reutilized MOF composites.

MOF-derived strategy for in-situ assembly of nickel phyllosilicate nanoflowers: Enhancing smoke suppression, flame retardancy and mechanical properties of epoxy resins

Epoxy resin (EP) is a highly versatile polymer extensively used in high-end applications, including aerospace components, electronics encapsulation and adhesives. To custom-design flame retardant materials for high-performance epoxy resins, a MOF-derived zeolitic imidazolate framework-8@nickel phyllosilicate (ZIF@Ni-PS) was synthesized through the in-situ assembly of nickel phyllosilicate nanoflowers. The results showed that the smoke suppression, flame retardancy, and mechanical properties of the EP composites containing 5 wt% ZIF@Ni-PS were significantly enhanced. The peak heat release rate (pHRR) and the peak smoke production rate (pSPR) were reduced by 33.2% and 12.7%, respectively. The presence of ZIF@Ni-PS promoted the formation of a dense, high-quality carbon layer that isolated heat and oxygen transfer, effectively reducing heat release during combustion and suppressing smoke generation. Furthermore, the imidazole ring and Zn ions on the surface of ZIF@Ni-PS facilitated the formation of coordination and hydrogen bonds with the epoxy (EP), thereby enhancing the dispersion, compatibility, and mechanical properties of the epoxy resin matrix. This study presents a straightforward preparation method for high-performance EP composites, providing a novel pathway for EP research.

Synergistic inhibition kinetics and mechanisms of polyethylene glycol – citric acid on non-caking coal oxidation at low temperature

ABSTRACT Focused on the insufficient efficacy of conventional flame retardants in mitigating coal spontaneous combustion (CSC), a novel composite flame retardant synthesized from polyethylene glycol (PEG) 2000 and citric acid (CA) is proposed. Through Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) experiments, the inhibitory kinetics and mechanisms were conducted. By enhancing heat absorption rate and enthalpy, with a significant increase by 90 kJ·mol−1 of activation energy, CSC resistance is improved. CA-metal ion interaction raises activation energy to inhibit methyl/methylene oxidation, while PEG disrupts aromatic oxidation by generating H ions upon hydration. This composite retardant offers a promising avenue for CSC mitigation in coal, enhancing coal fire safety.

Enhancing flame retardancy and mechanical strength of glass fiber-reinforced biomass polyamide composites with surface-functionalized black phosphorus

Fiber-reinforced polyamide exhibits exceptional mechanical properties and durability; however, its widespread application is impeded by potential fire hazards. In this study, a hybrid material consisting of black phosphorus (BP) and polyhedral oligomeric silsesquioxane (POSS) was synthesized, denoted as BP-CO-POSS. The fire safety of fiber-reinforced polyamide demonstrated significant enhancement upon the incorporation of aluminum diethyl phosphinate (Alpi) and BP-CO-POSS. This enhancement was evident in various aspects, including the suppression of heat release behaviors, reduction in the emission of toxic gases, and an increase in the UL-94 rating. Notably, with the additional inclusion of 0.5 wt% BP-CO-POSS, a substantial decrease in both heat release rate (31.15 %) and total heat release (37.59 %) was observed when compared to the application of Alpi and BP alone, thus affirming the existence of a synergistic effect. This observation was substantiated through a comprehensive analysis of results obtained from both gas and condensed phases. This study offers a practical methodology for the widespread utilization of phosphorus-rich advanced materials, thereby further enhancing the fire safety of fiber-reinforced polymers.

Enhanced flame retardancy and thermal insulation of epoxy resins composites incorporated with ammonium polyphosphate and ionic liquids loaded CuO-ZnO hollow spheres

Epoxy resin, as a thermosetting polymer material with good performance, has been limited in application due to its high flammability. In this investigation, porous CuO-ZnO hollow spheres (CZHS) were prepared by a hydrothermal method. By incorporation with ionic liquids loaded CuO-ZnO hollow spheres (CZHS@Ils) and ammonium polyphosphate (APP) into epoxy resin (EP) matrix, a new composite flame retardant material, named as EP/7.5APP/1.5CZHS@ILs, was developed for improvement of their thermal insulation and flame retardancy. The thermal conductivity of EP/7.5APP/1.5CZHS@ILs was measured to be 0.0197 W m −1 K −1, which is lesser than that of APP incorporated epoxy resin (EP/APP), demonstrating good thermal insulation capability. The flame retardancy were assessed using the limiting oxygen index (LOI) test, the Vertical flame testing (UL-94) test, and the cone calorimeter (CC) test. The results obtained from LOI test show that the EP/7.5APP/1.5CZHS@ILs has good flame retardancy with a LOI value of up to 28, better than that of pure EP which has a LOI value of 19.2. Moreover, a V-0 level of the EP/7.5APP/1.5CZHS@ILs was observed from the UL-94 test. The peak heat release rate (PHRR) was reduced to 257.9 kW m−2, which is 74.8 % lower than that of the pure EP. Such results are attributed to the synergy effect of CZHS@ILs and APP which offers the epoxy resin excellent flame retardancy. Taking advantages of the excellent thermal insulation, flame retardancy and better mechanical properties, the as-resulted EP/7.5APP/1.5CZHS@ILs may hold great potential for future thermal insulation and flame-retardant applications of energy saving building.

Developing flame retardant, smoke suppression and self-healing polyvinyl alcohol composites by dynamic reversible cross-linked chitosan-based macromolecule

With the increasing threat of white pollution to the public health and ecosystem, functional materials driven by green and sustainable biological macromolecule are attracting considerable attention. Inspired by the double-helix structure of DNA, a P–B–N ternary synergistic chitosan-based macromolecule (PBCS) was constructed to prepare flame retardant, smoke suppression and self-healing polyvinyl alcohol composite (PVA@PBCS) via dynamic reversible interactions. The limiting oxygen index value of PVA@PBCS increased from 19.6 % to 28.7 %, whereas the peak heat release rate and total heat release decreased by 47.04 % and 43.37 %, respectively. Besides, the peak smoke production rate and total smoke production of PVA@PBCS also decreased by 45.31 % and 54.98 %. With the presence of borate ester-based covalent and multiple hydrogen bonds, the tensile strength and elongation at break of PVA@PBCS increased by 19.50 % and 16.85 % compared to the control sample, and the healing efficiency for tensile strength and elongation at break was as high as 93.86 % and 90.57 %, respectively. This work developed an eco-friendly and effective scenario for fabricating flame retardant and smoke suppression PVA materials, stimulating the substantial potential of chitosan-based biomacromolecule and dynamic reversible cross-linked tactics in self-healing field.

Tri-source integrated adenosine triphosphate complexed copper ions anchored to boron nitride surfaces for enhancing flame protection of waterborne epoxy coatings

The abundant C, P, and N elements in the structure of adenosine triphosphate (ATP) can act as carbon, acid, and gas sources, and thus can be used as an efficient intumescent flame retardant. Here, a layer of polydopamine (PDA) with polyhydroxyl groups was firstly loaded on the surface of BN to provide a bridging effect for the surface modification of BN. Then, ATP-Cu was immobilized on the BN surface by complexation of ATP with Cu2+, resulting in an efficient inorganic-organic-metal composite flame retardant (BNP@ATP-Cu). This composite flame retardant effectively combined the high barrier effect of BN, the high swelling property of ATP and the catalytic carbon formation activity of Cu2+. The experimental results revealed that the EP loaded with BNP@ATP-Cu showed the lowest backside temperature (171.2 °C), indicating the highest thermal barrier effect. Moreover, BNP@ATP-Cu/EP exhibited the most significant swelling characteristics (22.7 mm, 17.46) and smoke suppression effect (42.8 %). In contrast, the carbon residue of BNP@ATP-Cu/EP (30.8 %) was significantly higher than that of the other coated samples, which was related to the combined effect of BN and ATP-Cu. The above relevant results fully demonstrated the effectiveness of the composite flame retardants in improving the fire resistance of epoxy coatings.

Flammability and thermal analysis of vertically oriented polyvinyl alcohol/DOPO derivative/MXene composite aerogel

The fabrication of ultralight high-performance flame-retardant composites significantly reduces fire risk for buildings. Flame retardation of porous polyvinyl alcohol (PVA) aerogels with directional arrangement is difficult. Herein, the polyvinyl alcohol/ 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative/two-dimensional (2D) MXene (PVA/DiDOPO/MXene) composite aerogel was prepared by ice template one-way freezing process. PVA-DiDOPO4 composite aerogel with an oriented porous structure reaches the V-1 level at the UL-94 test. Moreover, the peak heat release rate (pHRR) value of PVA-DiDOPO4 reduces to 452.26 (W/g) from 482.88 (W/g) of pure PVA. In addition, PVA/DiDOPO/MXene composite aerogel has improved thermal decomposition properties such as the maximum decomposition temperature (Tmax1) of the PVA-DiDOPO4 sample attains 319.92 °C from pure PVA of 302.90 °C. The design strategy of PVA combined 2D MXene nanosheet and DOPO derivatives construct oriented porous composite aerogel paves the way for the fabrication and customization of ultralight flame-retardant polymer composites, which can be expected to be applied in construction and reduce fire risk.

In situ preparation of MoS2@Fe3O4 by radiation method and its application in flame retardancy, mechanical properties, and friction properties of EVA composites

In recent years, there has been significant interest in using two-dimensional MoS2 to enhance flame retardancy, which has proven challenging. MoS2@Fe3O4 nanosheets were successfully synthesized via a one-step method called radiation reduction to boost MoS2’s flame retardant properties. Incorporating these MoS2@Fe3O4 nanocomposites notably improved the flame retardancy of ethylene vinyl acetate copolymer (EVA). Compared to pure EVA, EVA nanocomposites with 1 part of MoS2@Fe3O4 showed a 17.4% reduction in peak heat release rate, 40.4% decrease in total heat release, and 52.9% reduction in total smoke release, with scaly residue content improving from 0.4% to 12.6%. Additionally, MoS2@Fe3O4 incorporation enhanced the mechanical and friction properties of EVA composites, increasing tensile strength by 25.7% and elongation at break by 10.4% compared to pure EVA. This study presents an effective and simple method for producing modified MoS2 nanosheets that enhance flame retardancy, as well as mechanical and friction properties of EVA composites.

Preparation of halogen-free flame retardant curing agent and its application in epoxy resin

9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-N-Aminoethylpiperazine (DOPO-AEP), a phosphorus and nitrogen intumescent flame retardant curing agent was prepared by using acetonitrile as solvent using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and N-aminoethylpiperazine (AEP) as raw materials. The structure of the flame retardant curing agent DOPO-AEP was analyzed Fourier Transform Infrared Spectrometer (FTIR), Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometry (ESI-MS), and the synthesis method of the target product was determined. In addition, the content of char residue was determined by thermogravimetric analyzer, and its thermal properties were comprehensively explored, and based on the obtained results, the curable epoxy resin was selected to prepare DOPO-AEP/EP flame retardant composites. According to the amount of DOPO-AEP added product, different proportions of DOPO-AEP/EP flame retardant composites were prepared, and the actual impact of flame retardant properties and mechanical properties of epoxy resin in different proportions was explored. When the content of DOPO-AEP is 35%, the limiting oxygen index of DOPO-AEP/EP reaches 29.9, which has a significant increase compared with the limiting oxygen index of pure epoxy resin of 19.8, but compared with the content of DOPO-AEP of 30%, the limiting oxygen index of DOPO-AEP/EP is 28.7, and there is no significant increase change. Comprehensive analysis shows that when the component content of DOPO-AEP is 30%, the flame retardant system has a tensile strength of 29.0 MPa, an impact strength of 4.5Kj/m2 and a flexural strength of 73.9 MPa, and its limiting oxygen index is as high as 28.7, and the comprehensive performance of the system is the best. By testing the surface morphology of the flame retardant composites after combustion by SEM, it was found that a dense char layer was formed on the surface of the epoxy resin cured char residue and foamed obviously, indicating that the flame retardant curing performance of DOPO-AEP was good.

A gradient flame retardant strategy to improve the overall performance of polylactic acid/fiber composites

AbstractTo enhance the flame retardant property of fiber‐reinforced polymer composites without adding more flame retardants, we prepared film stacking composites by maintaining a total flame retardant content of 20% and applying a gradient flame retardant strategy. The gradient composites have been designated as 3113FRPLA/F and 1331FRPLA/F, respectively. 3113FRPLA/F is characterized by an augmented concentration of fire‐resistant additives in the surface layer, while 1331FRPLA/F features a reduced content. 20%FRPLA/F is prepared with a homogeneously distributed flame retardant composition. Results derived from LOI test and cone calorimeter test unequivocally demonstrate that 3113FRPLA/F outperforms both 1331FRPLA/F and 20%FRPLA/F in improving flame retardancy. The LOI value of 3113FRPLA/F is 36.1%, exceeding that of 20%FRPLA/F and there is also a reduction in the pk‐HRR compared with 20%FRPLA/F. It is of interest to note that 3113FRPLA/F exhibits the most effective heat insulation properties while 20%FRPLA/F has the worst, which is reflected by the infrared thermal imaging results. It bears mention that the impact strength and tensile strength of 3113FRPLA/F surpasses that of 20%FRPLA/F. In summary, 3113FRPLA/F, characterized by its increased surface concentration of flame retardants, demonstrates the most superior overall performance.Highlights The characteristics of PLA/fiber composites using a gradient strategy were compared. The LOI value of 3113FRPLA/F is 36.1%, exceeding that of 20%FRPLA/F. 3113FRPLA/F has the best heat insulation effect while 20%FRPLA/F has the worst. The impact strength and tensile strength of 3113FRPLA/F surpasses 20%FRPLA/F. Improving the surface flame retardant concentration increases the overall property.

Effect of synergistic flame retardancy on the flame retardant and smoke suppression properties of bamboo fiber composites

Effect of synergistic flame retardancy on the flame retardant and smoke suppression properties of bamboo fiber composites

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.

A high-temperature-triggered crosslinking reaction to achieve excellent intrinsic flame retardancy of organic phase change composites.

The host-guest composite that integrates a porous scaffold and organic phase change materials (PCMs) features high energy density and customizable function, promising for advanced thermal storage/utilization. However, highly flammable organic PCMs are prone to severe combustion in porous structures, making it challenging for traditional flame-retardant methods to balance fire safety and latent heat. Herein, a high-temperature-triggered crosslinking reaction between the host and guest is designed using a polybenzoxazine-based aerogel (PB-1) and benzoxazine-based PCMs (C-dad). At high temperatures, the ring-opening polymerization (ROP) of C-dad can be initiated by and reacted with the phenolic groups of PB-1 to form a polybenzoxazine copolymer monolith with an improved char yield and intrinsic low flammability and without using the typical flame-retardant components. This enables the obtained composite (PB-1/C-dad) to well balance latent heat (145.3 J g-1), char yield (a char residue of 13.1% at 600 °C), and flame retardancy (a peak heat release rate of 231 W g-1), outperforming the representative flame-retardant modified polymer/organic PCM complexes reported in the literature. This thermal-triggered mechanism allows PB-1/C-dad to be repeatedly and stably used within the working temperature and activates its flame retardancy when exposed to open flames. The proposed host-guest crosslinking strategy is believed to inspire the development of inherently nonflammable phase change composites for safer thermal management.

Novel method for finishing nonwoven fabrics from domestic raw materials with flame retardant and antimicrobial properties

This study aims to obtain a non-woven material with flame retardant and biocidal properties, considering the use of salicylic acid, copper sulfate, and guanidine hydrochloride in a finishing composition, based on preliminary studies. The concentrations of copper sulfate, guanidine hydrochloride, and salicylic acid were varied, respectively, within 1–5 g/L, 5–15 g/L, and 3–7 g/L. The conditions of the finishing process involved the application of the aqueous solutions, by spraying on the surface of the material, followed by drying at 120 °C for 5 min and heat treatment at 180 °C on a thermal press. In the production of nonwovens, treatment with a flame retardant and biocidal composition can be combined with emulsification of a mixture of fibers, or carried out after the formation of the canvas with subsequent heat treatment and calendering. The untreated sample of non-woven material, when tested for flammability with an ignition time of 15 s, burns completely in 40 s. For the sample treated by the proposed method, the self-burning is reduced to zero (DIN 53906). To study the biocidal activity, a microbiological essay was conducted according to ASTM E2149. It was found that the tested sample exhibits fungicidal activity against the tested strains. In addition, tests conducted on the skin-irritating effects of nonwovens treated with the proposed method have shown its safety for human health.

DOPO chemically modified mesoporous silica composites: Preparation, flame retardancy, and thermodynamic properties

AbstractOrganic flame retardant 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) was used to decorate the pores of mesoporous silica (m‐SiO2) nanospheres to prepare a new composite flame retardant (DK‐SiO2). The content of DOPO in DK‐SiO2 is about 17 wt%. Due to the chemical bonding, DK‐SiO2 not only enhances the flame retardant performance, but also effectively avoids adverse effects of DOPO on the glass transition temperature and mechanical properties of epoxy resin (EP). At 9 wt% loading, the limiting oxygen index of the EP increased from 25.7 to 31.2, and successfully passed the UL‐94 V‐0 rating. Besides, DK‐SiO2 can significantly reduce the peak heat release rate, total heat release, and total smoke production of EP, with reductions of 26%, 32%, and 20.8%, respectively. Compared with the simple blended sample, DK‐SiO2 not only has better flame retardant performance but also shows significant advantages in thermodynamic properties. The glass transition temperature, impact, and tensile strength, as well as storage and flexural modulus have been improved. This excellent flame retardant performance is mainly attributed to the gas‐condensed synergistic flame retardant mechanism between DOPO and m‐SiO2. The good thermodynamic performance is due to the excellent dispersion of DK‐SiO2 nanospheres in the EP.