Limiting Oxygen Index Test Research Articles

Development of eco-friendly flame-retardant polyurethane using sustainable additives

Polyurethane (PU) stands as a pivotal polymer extensively employed in architecture, particularly for insulation in residential and industrial buildings, but the inherent flammability of PU poses a significant drawback, leading to the generation of hazardous fumes and gases; this demerit limits PU applications in various fields. Therefore, the development of environmentally friendly flame-retardant PU is of great significance practically. In this research, some attempts have been made to synthesize PU modified with three different flame-retardants separately: Lipids (soybean, oil, jojoba), Eggshells (CaCO3), and Lignin phosphate prepared from rice straw as sourced sustainably. The results of the Limit Oxygen Index (LOI) test for the raw sample without the addition of inhibitors showed 18.5%, while the sample with flame retardants was 23.5%, it has better thermal stability and the UL-94 grade advanced to “V0″. This study showed excellent promise as green additives for enhancing the mechanical, thermal and flame retardancy performance of these 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.

The Effect of Di-Ammonium Phosphate (DAP) towards Flammability Properties of Polyester-Cotton Military Fabrics

Polyester-cotton fabric is one of the most common materials used in military fabrics. The study of the suitable fabric material is critical because military personnel must prepare themselves from inevitable events such as heat exposure. Therefore, the purpose of this study was to examine the flammability features of various cotton compositions in polyester-cotton military textiles with and without the presence of Di-ammonium Phosphate (DAP). We performed a full flammability test, including a cone calorimeter test and a limited oxygen index (LOI) test on three distinct types of polyester-cotton textiles treated with 10% di-ammonium phosphate (DAP). The result shows that, the higher the percentage of cotton, the lower the fire-retardant properties. Besides that, this study also found that the di-ammonium phosphate (DAP) improves the flammable properties of the military fabric.

Synthesis and analysis of a novel phospho-nitrile flame retardant for cotton fabric

Phospho-nitrile flame retardant is a kind of phosphorus and nitrogen flame retardants with the characteristics of non-toxic, environmental protection and high efficiency, which deserves to be researched in depth. In this study, dopamine (DA) is grafted onto hexachlorocyclotriphosphonitrile (HCCP) to synthesize novel phospho-nitrile flame retardants (hexadopamine cyclotriphosphonitrile, HDCCP) by acylation reaction. The structures of HDCCP are characterized by Fourier transform infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR) and Gaussian. The pyrolysis process of HDCCP is characterized by thermal gravity analyzer (TGA), and the results demonstrate that the HDCCP has good thermal stability properties. The optimal preparation process is determined by orthogonal test and vertical combustion test (VBT). Eventually, crystallinity analysis (XRD), scanning electron microscope observation (SEM), limiting oxygen index test (LOI) and TGA are applied to investigate the flame-retardant properties of cotton fabrics with different mass concentration of the HDCCP. The results indicate that the flame retardant containing 6 wt% HDCCP not only exhibits the optimal flame retardancy, but also maintains excellent mechanical property.

Coumarin-DPPO a new bio-based phosphorus additive for poly(lactic acid): Processing and flame retardant application

This study addresses very important aspects of the sustainable development of new flame retardant materials: (i) the preparation of a novel flame retardant (FR) additive from bio-resource, (ii) its use as FR additive in poly(lactic acid) (PLA) based composites and, (iii) the in vitro toxicity assessment of the FR. The synthesis of this bio-based FR additive was achieved through a phospha-Michael addition of diphenylphosphine oxide (DPPO) and the naturally occurring compound coumarin, yielding 4-(diphenylphosphoryl)chroman-2-one (CU-DPPO). The flame-retarded CU-DPPO PLA composites were prepared either via conventional melt blending of commercially available PLA or through reactive extrusion (REX) of L-lactide. Characterization of the composites was performed through nuclear magnetic resonance (NMR), size exclusion chromatography (SEC) and thermogravimetric analysis (TGA). TGA analysis of the FR-PLA composites showed an increase in thermal stability, confirming the beneficial effect of the CU-DPPO additive. Direct insertion probe mass spectrometry (DIP-MS) analysis was used to gain insight on the mechanism of action of the FR additive, suggesting gas-phase activity. Rheological measurements exhibited the thermo-oxidative stabilizing effect in the modified PLA. The flame retardancy of the melt-blended PLA composites with CU-DPPO was investigated by limited oxygen index (LOI), cone calorimetry and vertical burning tests (UL 94 and BKZ-VB). Samples containing 10 wt.% of CU-DPPO showed improved fire performance with a limiting oxygen index (LOI) of 29%, passing Swiss vertical burning test (BKZ-VB) and obtaining a V-0 rating in the UL 94 test. Moreover, a preliminary toxicity assessment of the CU-DPPO, carried out using an established in vitro platform, showing no adverse effects on cell viability.

Processing Method and Performance Evaluation of Flame-Retardant Corrugated Sandwich Panel.

In this study, in order to expand the engineering application range of thermoplastic corrugated sheets, flame-retardant thermoplastic corrugated sheets were prepared by the thermoplastic molding method. Based on our previous research results, we prepared flame-retardant prepreg tapes with the flame retardant addition accounting for 15%, 20%, and 25% of the resin matrix. Then, we prepared flame-retardant thermoplastic corrugated sandwich panels with corresponding flame retardant addition amounts. The limiting oxygen index test, vertical combustion test, cone calorimetry test, and mechanical property test were carried out on each group of samples and control group samples. The results showed that when the flame retardant was added at 25%, the flame retardant level could reach the V0 level. Compared with the control group, the flexural strength and flexural modulus decreased by 2.6%, 14.1%, and 19.9% and 7.3%, 16.1%, and 21.9%, respectively. When the amount of flame retardant was 15%, 20%, and 25%, respectively, the total heat release decreased by 16.3%, 23.5%, and 34.1%, and the maximum heat release rate decreased by 12.5%, 32.4%, and 37.4%, respectively.

Novel multifunctional nanocomposites containing graphitic carbon nitride/silanized Nb2O5 nanofillers for the protection of steel surfaces in the automobile industry

The inorganic nanofiller niobium pentoxide (Nb2O5) was altered with [3-(2-aminoethylamino)propyl]trimethoxysilane (AEPS) and the resulting AEPS/Nb2O5 was encased with graphitic carbon nitride (GCN) in pure epoxy resin (EP). The protection performance of mild steel coated with epoxy in the presence of various concentrations of GCN encapsulated in silanized Nb2O5 was investigated using electrochemical techniques in a marine environment. A limiting oxygen index (LOI) test showed that GCN/AEPS-Nb2O5 considerably enhanced the flame retardancy properties of the epoxy coating. The PHRR and THR values for EP-GCN/AEPS-Nb2O5 significantly decreased by 81 % and 69 %, respectively, compared to those of pure EP, showing that the material is more flame-retardant. The results of salt spray tests showed that the addition of GCN/AEPS-Nb2O5 enhanced corrosion protection and reduced water absorption. Even after 960 h of exposure to seawater, epoxy-GCN/AEPS-Nb2O5 exhibited increased coating resistance of 8.99E9 Ω.cm2, according to the EIS measurements. According to SECM research, coated steel made of the EP-GCN/AEPS-Nb2O5 nanocomposite has the lowest degree of ferrous ion dissipation (1.0 I/nA). According to the FE-SEM/EDX results, the decomposition products of silanized GCN were enhanced, generating a sturdy inert nanolayered coating. To prevent ions from penetrating the specimen, EP-GCN/AEPS-Nb2O5 crystallizes into a strong, inert coating, has greater adhesive strength, and can endure prolonged immersion without losing its integrity. Therefore, the EP-GCN/AEPS-Nb2O5 nanocomposite could act as a viable coating component in the automobile industry.

Flame-Retardant GF-PSB/DOPO-POSS Composite with Low Dk/Df and High Thermal Stability for High-Frequency Copper Clad Applications.

In the field of high-frequency communications devices, there is an urgent need to develop high-performance copper clad laminates (CCLs) with low dielectric loss (Df) plus good flame retardancy and thermal stability. The hydrocarbon resin styrene-butadiene block copolymer (PSB) was modified with the flame-retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide/polyhedral oligomeric silsesquioxanes (DOPO-POSS) to meet the demands of high-frequency and high-speed applications. The resulting DOPO-POSS-modified PSB was used as the resin matrix along with other additives to fabricate PSB/DOPO-POSS laminates. At a high-frequency of 10 GHz, the laminates containing 20 wt.% of DOPO-POSS and with a thickness of 0.09 mm exhibited a Df of 0.00328, which is much lower compared with the commercial PSB/PX-200 composite (Df: 0.00498) and the PSB without flame retardancy (Df: 0.00453). Afterwards, glass fiber cloth (GF) was used as a reinforcing material to manufacture GF-PSB/DOPO-POSS composite laminates with a thickness of 0.25 mm. The flame retardancy of GF-PSB/DOPO-POSS composite laminate reached vertical burning (UL-94) V-1 grade, and GF-PSB/DOPO-POSS exhibited higher thermal and dynamic mechanical properties than GF-PSB/PX-200. The results of a limited oxygen index (LOI) and self-extinguishing time tests also demonstrated the superior flame-retardant performance of DOPO-POSS compared with PX-200. The investigation indicates that GF-PSB/DOPO-POSS composite laminates have significant potential for use in fabricating a printed circuit board (PCB) for high-frequency and high-speed applications.

Phosphorous containing poly(amidoamine-organosilicon) (P@PAMAMOSi) flame retardants: Synthesis and sol-gel application on cotton fabrics

A novel hyperbranched phosphorous containing poly(amidoamine-organosilicon) (P@PAMAMOSi) was successfully synthesized and the structure was characterized by fourier transform infrared spectra (FT-IR) and NMR. The cotton fabrics were wrapped with P@PAMAMOSi by sol-gel method. The P@PAMAMOSi modified cotton fabrics were proven by FT-IR and scanning electron microscopy (SEM). The thermal stability and combustion properties of the blank cotton and treated cotton fabrics were explored by thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical flammability, and cone calorimetry. The data of TGA indicated that modified cotton fabrics have exquisite thermal stability, when the temperature reached 700 °C, the char residues of A30 treated cotton, B30 treated cotton, and C30 treated cotton were 29.5, 34.5, and 28.8 %, respectively; which is better than the 12.7 % of blank cotton. The results were verified by the LOI and combustion tests of cotton fabrics. The flame-retardant mechanism of treated cotton fabrics was analyzed by the FT-IR, X-ray photoelectron spectrometry (XPS), SEM, and energy dispersive X-ray spectroscopy (EDS), the treated cotton fabrics showed condensation phase and gas phase flame retardant mechanism. In addition, treated cotton fabrics showed desirable physical properties and mechanical properties.

Армированные композитные материалы на основе фосфорсодержащих связующих с перспективными физико-механическими и пожаробезопасными свойствами

In this work, a comparative analysis of the properties of glass fiber-reinforced epoxy resin (ED-20) composites and composites based on glass fiber-reinforced phosphorus-containing ester methacrylate oligomers (PEAO) was carried out. Reinforced fiberglass plastics made on the basis of PEAO have demonstrated promising fireproof characteristics, especially in limited oxygen index and smoke emission tests. It is also worth noting that the mechanical properties of materials based on phosphorus-containing ester-acrylate resins are outstanding. The samples of a widely used glass fiber reinforced epoxy resin ED-20 with 9,10-dihydro-9-hydroxy-10-phosphaphenanthrene-10-oxide-4,4`-diaminodiphenylmethane (DDM-DOPO) additive demonstrated lower flammability compared to the samples without fire retardant additives. A mixture of DDM-DOPO and graphene added to the samples led to a low smoke generation rate of the samples; however, the rate was 1.5-2 times higher than that of the samples based on phosphorus-containing ester methacrylate resins. The addition of fire retardants has reduced the mechanical properties of fiberglass plastics based on epoxy resin, which can be a problem for the use of these materials in the aviation industry. These results clearly show better prospects of using fiberglass-reinforced plastics based on phosphorus-containing ester methacrylate oligomers in comparison with modified plastics based on the widely used epoxy resin.

Influence of Zinc Oxide Nanoparticles on Flame Resistance in Wood Plastic Composites

The interest in wood plastic composites (WPCs) has increased in recent years. The utilization of environmentally friendly materials has been of great significance due to the overwhelming pressure on nature. As a widely used material, plastic is, however, easily combustible due to its structure. In this study, WPCs were reinforced with zinc oxide (ZnO) nanoparticles. The effect of higher content of ZnO nanoparticles (1, 3, 5, 10 %) on WPCs thermal stability and fire performance was investigated. Thermogravimetric analysis (TGA) clearly demonstrated that nanoparticles acted as a shield, which inhibited heat transfer and increased the degradation temperature thanks to covering the surface of materials. Free radicals accelerated the thermal degradation of neat-HDPE (high-density polyethylene) by oxidative reactions, while ZnO nanoparticles reduced the degradation velocity. Moreover, the increase in nanoparticle content significantly affected the residue. The fire performance of WPCs was also investigated by the limit oxygen index (LOI) test. While neat-HDPE flamed with dripping, ZnO nanoparticles made flaming difficult for WPCs. Therefore, the LOI values increased with increasing nanoparticle content up to 28.5 %, which indicated the need for more oxygen. The improvement reached up to 54 % compared to neat HDPE. Moreover, the char forming was also improved, which helped enhance the fire resistance. The scanning electron microscope (SEM) investigation indicated that nanoparticles were well dispersed in the matrix. However, the tendency to agglomerate increased with the increase of concentration. The ability of carbonization of wood fiber surface during the combustion also contributed to improving thermal stability and fire performance.

Effect of flame‐retardant melamine and dispersants on the mechanical, thermal, and foaming properties of flexible polyurethane foam

AbstractThe objective of this study was to investigate the effect of adding flame‐retardant melamine and five different dispersants on the precipitation, foaming, mechanical, and thermal properties of flexible polyurethane foam (FPUF). Precipitation experiments were conducted to analyze the effect of dispersant on the separation of flame retardant and polyol, and the foaming characteristics of polyurethane (PU) foam after adding dispersant were analyzed. The effect of adding a dispersant on mechanical strength was characterized by measuring tensile strength, tearing strength, and hardness, and scanning electron microscopy analysis was performed to analyze morphological characteristics. Thermogravimetric analysis (TGA) was performed to analyze the thermal properties of PU foam. A horizontal flame test, limiting oxygen index test, and cone calorimeter tests were conducted to examine the flame retardancy of PU foam with flame retardant melamine and dispersant added. The dispersant ANTI‐TERRA‐U is a solution of a salt of unsaturated polyamine amides and low‐molecular acidic polyesters. And, the dispersant BYK‐220S is a solution of a low molecular weight, unsaturated acidic polycarboxylic acid polyester with a polysiloxane copolymer. The dispersants ANTI‐TERRA‐U and BYK‐220S improved the density, tensile strength, tear strength, and hardness of FPUF. TGA of the top and bottom portions of the foam showed less weight difference for samples containing dispersants, indicating better homogeneity due to improved dispersibility. Therefore, we conclude that dispersants are beneficial additives to improve the mechanical properties and dispersibility of PU foam.

Effect of Rice Husk and Wood Flour on the Structural, Mechanical, and Fire-Retardant Characteristics of Recycled High-Density Polyethylene.

Given the rising consumption of plastic products, it is becoming imperative to prioritize the recycling of plastic items as a solution to reducing plastic waste and environmental pollution. In this context, this research focuses on assessing the impact of incorporating rice husk and wood flour into recycled high-density polyethylene (rec-HDPE) to analyze its mechanical properties, flammability, and thermal stability. The combined rec-HDPE content of wood flour and rice husk varied between 0% and 20%. The rec-HDPE content of maleic anhydride grafted polyethylene (MAPE) was fixed at 3%. Mechanical characteristics such as flexural, tensile, and impact strengths were assessed. Cone calorimetry (CC) tests, limited oxygen index (LOI) tests, and horizontal and vertical burning tests were performed to determine the flammability or fire retardancy of these composites. On the other hand, to characterize the thermal characteristics of these composites, thermogravimetric analysis (TGA) was used. To further characterize the fluctuation in these characteristics, scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) studies were carried out. The mechanical characteristics were found to be increased in response to adding rice husk or wood flour. An 8% increase in tensile strength and a 20% increase in elastic modulus enhancement were recorded for a 20% rice husk-added composite. SEM revealed the reason for the variation in tensile properties, based on the extent of agglomeration and the extent of uniform distribution of fillers in rec-HDPE. Following these lines, the 20% rice husk-added composite also showed a maximum increase of around 6% in its flexural strength and a maximum increase of 50% in its flexural modulus. A decrease in impact strength was recorded for rice husk and wood flour-reinforced composites, compared with unreinforced rec-HDPE. Hybrid composites displayed a lack of mechanical strength due to changes in their nature. FTIR tests were performed for a much more elaborate analysis to confirm these results. Twenty percent of rice husk-added rec-HDPE displayed the best thermal properties that were tested, based on TGA and derivative thermogravimetric (DTG) analysis. This 20% composite also displayed the best fire-retardancy characteristics according to UL 94 tests, cone calorimetry tests, and limited oxygen index tests, due to the barrier created by the silica protective layer. These tests demonstrated that the incorporation of both fillers-rice husk and wood flour-effectively enhanced the thermal, mechanical, and fire-retardant attributes of recycled HDPE.

Eco-friendly Synthesis of Novel Phosphorus Flame Retardants for Multiple Purposes

The synthesis methods of most parts of phosphorus (P)-based flame retardants apply harmful and toxic reagents, and the formation of byproducts is often inevitable. The synthesis of P-based flame retardants (FRs) according to the green chemistry approach has been investigated. Two FRs have been prepared via an addition reaction of phosphorus-pentoxide and alcohols. These molecules can be used as additive FRs after salt formation or as precursors for flame retardant surface treatments of natural fibers. The flame retardant efficacy of the synthesized additives was assessed in a bioepoxy resin system through UL-94 and limiting oxygen index tests, while their mode of action was determined by the investigation of gas-phase degradation products and thermogravimetric analysis (TGA). The prepared adduct was also used in the formulation of a reactive flame-retardant surface treatment for cellulosic fibers. In TGA tests, the treated fibers produced significant amounts of char residue.

Jute woven fabric modified by phosphorus‐containing organosilicon compound reinforced flame retardant polylactic acid composites with enhanced flame retardant and mechanical properties

AbstractBalancing the flame retardant properties and mechanical performance is important for flame retardant composites. In this research, the polylactic acid (PLA)/fiber composite is prepared by treating jute woven fabric with phosphorus‐containing organosilicon compound (PCOC) and adding intumescent flame retardant (IFR) to PLA using a film‐stacking procedure, which is named flame retardant PLA (FRPLA)/PC‐F. The flame retardancy and mechanical properties of PLA/fiber composites were studied and analyzed. Mechanical/flame retardant index (M/F index) was developed to compare the comprehensive properties of the composites. The limited oxygen index (LOI) test results show the LOI value of FRPLA/PC‐F reaches 34.1%, 14.1% higher than untreated PLA/fiber composite (PLA/F). In the cone calorimeter test, the pk‐heat release rate (HRR) value of FRLA/PC‐F decreases from 549 to 388 kW/m2 compared with PLA/F. In addition, the char yield of FRPLA/PC‐F increases from 1.9% (PLA/F) to 18.6%. The scanning electron microscope images of the char yield for FRPLA/PC‐F obtained from cone calorimetry test shows a continuous network structure with the fibrous skeleton completely wrapping by the dense and uniform char layer, which plays a barrier effect that inhibits the release of volatile substance and the transfer of heat. Meanwhile, FRPLA/PC‐F exhibits 28% and 19% improvement in tensile strength and impact strength compared with PLA/F due to the boost of interfacial adhesion between fiber and PLA. The M/F index of FRPLA/PC‐F is 1.15, which is the highest among all the composites, proving the best comprehensive properties and practical applicability. The results in this manuscript above make a great development, which is attractive in the design of PLA/fiber composites with great comprehensive performance.

A highly efficient, colorless phosphorus–nitrogen synergistic flame retardant for durable flame retardancy in wood pulp paper

Wood pulp paper (WPP) is an exemplary substrate material, yet its flammability impedes the widespread application in diverse functional fields. Herein, a highly effective, colorless and transparent phosphorus–nitrogen flame retardant, namely ammonium salt of tris(hydroxymethyl)aminomethane diphosphonic acid (AMPAP-NH4+) without halogen and formaldehyde, has been synthesized for WPP. Chemical grafting was employed to confer highly durable flame retardancy to the WPP, enabling it to maintain excellent fire resistance after functionalization. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analysis demonstrated that AMPAP-NH4+ was directly linked to cellulose fibers via POC bonds, effectively introducing P and N elements into the WPP without altering the surface morphology of the fibers. Results from thermogravimetric analysis, vertical burning test, limiting oxygen index test, cone calorimeter test and thermogravimetric-Fourier infrared spectrometer test demonstrated that the treated WPP exhibited outstanding flame retardancy. The peak heat release rate (pHRR) and total heat release (THR) values decreased by 80.8% and 70.9%, respectively, and the limiting oxygen index (LOI) increased to 41.4%. Furthermore, due to the stability of the POC bond, the treated samples remained unignited after 168 h, with a high LOI value of 35.3%. In summary, AMPAP-NH4+ serves as a phosphorus–nitrogen synergistic transparent flame retardant that can effectively and durably impart paper with flame retardancy without altering its surface morphology.

Ultraviolet (UV) curable hybrid material based on palm oil: plasticization effect and flame retardancy

In this study, a UV curable hybrid material from palm oil was prepared with glycerol and glycidyl methacrylate (GMA). However, the resin was brittle and flammable. Thus, tri-n-butyl phosphate (TnBP) and polypropylene glycol 400 (PPG) were added in the formulation as a flame retardant and plasticizer respectively. From the results, the gel content of UV cured films were more than 95%. The hardness, adhesion strength, impact, water absorption and wettability of the films were influenced by PPG 400 content as well as TnBP percentage. In addition, the flame retardant properties of coated wood were enhanced by PPG 400 and TnBP too. The results show that high oxygen concentration was needed to ignite the sample with a high amount of PPG 400 and TnBP. The flame retardant properties of the sample were the best for a combination of 15% PPG 400, and 5% TnBP, in the determination of limited oxygen index (LOI), UL 94 and Methenamine pill test.

A new bio‐based flame retardant simply synthesized: Improving the flame retardancy and thermal stability of low‐density polyethylene together with melamine cyanurate

AbstractA novel bio‐based flame retardant, MHPA, was synthesized with magnesium hydroxide (MH) and phytic acid (PA) and was added to low‐density polyethylene (LDPE) with melamine cyanurate (MCA) to investigate the flame retardant, mechanical property and thermal stability of the LDPE composites. The limit oxygen index (LOI) and cone calorimeter test (CCT) results showed that the combination of MHPA and MCA can increase the LOI of LDPE composite to 21.6%, and its peak of heat release rate (pHRR), total heat release (THR) and total smoke production (TSP) values reduced by 46.8%, 20%, and 31.6% respectively compared with pure LDPE, while the residue after CCT was increased to 24.4%. Moreover, the addition of MCA can effectively improve the thermal stability of LDPE/MHPA composites and suppress their early decomposition.

Flame retardant properties of Viscose/Carrageenan fibers blend papers

Viscose fiber (VIF) burns easily, bio-based carrageenan fiber (CAF) is inherently flame retardant. Can the addition of carrageenan fibers improve the flame retardant properties of VIF/CAF blended materials? In this study, VIF/CAF papers were successfully prepared in a green way without any pollution. The thermal degradation properties and flame retardancy of VIF/CAF papers were tested by thermogravimetric analysis, limiting oxygen index test, flammability test and cone calorimeter test. The results showed that the introduction of carrageenan fibers significantly changed the thermal stability and flame retardancy of VIF/CAF papers. Moreover, the addition of carrageenan fibers obviously increased the mechanical strength of the VIF/CAF papers.

Influence of the Crystal Structure of Melamine Trimetaphosphate 2D Supramolecules on the Properties of Polyamide 6.

To explore the influence of the crystal structure difference of melamine trimetaphosphate (MAP) on the application performance of its polymer composites, an intumescent flame retardant with the optimal crystal type was designed and synthesized to improve the mechanical properties and flame retardancy of polyamide 6 (PA6). I-MAP and II-MAP were obtained using different concentrations of MA and sodium trimetaphosphate (STMP) in an acidic aqueous solution. The morphology, chemical composition, and thermal stability were comprehensively characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The dispersion, mechanical properties, and flame retardancy of PA6/I-MAP and PA6/II-MAP were evaluated by SEM, stress and strain, limiting oxygen index test (LOI), vertical burning test (UL-94), cone calorimetry (CONE) test, and char residue analysis. The conclusion is as follows: I-MAP and II-MAP have a greater influence on the physical properties of PA6 but less influence on the chemical properties. Compared with PA6/I-MAP, the tensile strength of PA6/II-MAP is 104.7% higher, the flame rating reaches V-0, and PHRR is reduced by 11.2%.