Search

With the advantages of lightweight and low thermal conductivity properties, polymeric foams are widely employed as thermal insulation materials for energy‐saving buildings but suffer from inherent flammability. Flame‐retardant coatings hold great promise for improving the fire safety of these foams without deteriorating the mechanical‐physical properties of the foam. In this work, four kinds of sulfur‐based flame‐retardant copolymers are synthesized via a facile radical copolymerization. The sulfur‐containing monomers serve as flame‐retardant agents including vinyl sulfonic acid sodium (SPS), ethylene sulfonic acid sodium (VS), and sodium p‐styrene sulfonate (VSS). Additionally, 2‐hydroxyethyl acrylate (HEA) and 4‐hydroxybutyl acrylate are employed to enable a strong interface adhesion with polymeric foams through interfacial H‐bonding. By using as‐synthesized waterborne flame‐retardant polymeric coating with a thickness of 600 µm, the coated polyurethane foam (PUF) can achieve a desired V‐0 rating during the vertical burning test with a high limiting oxygen index (LOI) of >31.5 vol%. By comparing these sulfur‐containing polymeric fire‐retardant coatings, poly(VS‐co‐HEA) coated PUF demonstrates the best interface adhesion capability and flame‐retardant performance, with the lowest peak heat release rate of 166 kW m−2 and the highest LOI of 36.4 vol%. This work provides new avenues for the design and performance optimization of advanced fire‐retardant polymeric coatings. [ABSTRACT FROM AUTHOR]

The combined effects of an organically modified montmorillonite (OMMT) and an intumescent flame retardant, poly (piperazine spirocyclic pentaerythritol bisphosphonate) (PPSPB), in (low-density polyethylene)/[ethylene-(vinyl acetate) copolymer] (LDPE/EVA) nanocomposites were observed. The results from X-ray diffraction and transmission electron microscopy studies showed that exfoliated LDPE/EVA/PPSPB/OMMT nanocomposites were formed. Thermal stability and flammability properties were investigated by thermogravimetric analysis and cone calorimeter tests. The combination of PPSPB and montmorillonite improved thermal stability and reduced significantly the flammability, including peak heat release rate (PHRR), total heat release, average mass loss rate, etc. The PHRR of LDPE/EVA/PPSPB/OMMT was reduced by about 50% compared to that of an LDPE/EVA blend. The morphology and composition of the residues generated by cone calorimeter tests were investigated by scanning electronic microscopy (SEM) and energy dispersive X-ray (EDX) analysis. The results of SEM showed that a compact and dense intumescent char was formed from the LDPE/EVA/PPSPB/OMMT nanocomposite upon combustion. The results of EDX examination revealed that the carbon content of this char was increased significantly by the combined effect of PPSPB and montmorillonite. J. VINYL ADDIT. TECHNOL., 19:285-292, 2013. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

A series of phosphorus–nitrogen-containing quaternary ammonium salts (PNQASs) were designed and synthesized for use as clay modification reagents to investigate the impact of their chemical structure on the morphology and flammability properties of nanocomposites obtained by in situ polymerization. The composition, chain length, and polarity of PNQASs are closely related to the formation of nanocomposites and thus affect the flame retardancy of the materials. The dispersion of montmorillonite (MMT) modified by a PNQAS (PNQAS–MMT) in a poly(methyl methacrylate) matrix was identified by using wide-angle X-ray scattering (WAXS) and transmission electron microscopy (TEM). The WAXS and TEM results showed well-dispersed systems obtained by introducing a phosphorus–nitrogen group into the PNQAS or increasing the chain length of the PNQAS. Thermogravimetic analysis and cone calorimeter experiments showed that the thermal stability and flammability properties were improved for the PMMA/PNQAS–MMT systems, particularly for the well-dispersed clay modified with high phosphorus and nitrogen content PNQAS composites. This understanding should lead to better design of clay modifications for use in flame-retardant polymer nanocomposites. [ABSTRACT FROM AUTHOR]

Abstract: A phosphoruscontaining compound, N-(2-(5,5-dimethyl-1,3,2-dioxaphosphinyl-2-ylamino)-hexylacetamide-2-propyl acid (PAHPA), is synthesized and characterized. A novel flame retardant, namely layered double hydroxides (LDHs) modified with PAHPA (PAHPA-LDHs), is prepared by ion-exchange of LDHs with PAHPA. The results from Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and energy dispersive X-ray analysis with a high-angle annular dark-field scanning transmission electron microscope show that PAHPA intercalated LDHs. The X-ray diffraction and transmission electron microscopy (TEM) results show that PAHPA-LDHs achieve well dispersion in ethylene vinyl acetate copolymer (EVA) matrix and the EVA/PAHPA-LDHs nanocomposites (i.e. EVA filled with 5wt% PAHPA-LDHs) are formed by polymer melt intercalation. Thermal stability and flammability properties are investigated by thermogravimetric analysis and cone calorimeter tests. The results show that the addition of PAHPA-LDHs improves thermal stability and reduces obviously the flammability of EVA resin. Compared with pure EVA resin, the peak heat release rate of the EVA/PAHPA-LDHs nanocomposites is reduced by about 43%. The results of scanning electron microscopy and TEM indicate that a compact and dense intumescent char is formed for the EVA/PAHPA-LDHs nanocomposites after combustion. [Copyright &y& Elsevier]

Abstract: An intumescent flame retardant, poly(piperazine spirocyclic pentaerythritol bisphosphonate) (PPSPB), has been covalently grafted onto the surfaces of graphene oxide (GO) to obtain GO–PPSPB and according nanocomposites were prepared via solvent blending. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that the chemically reduced GO–PPSPB (CRG–PPSPB) can achieve better dispersion in the ethylene vinyl acetate copolymer (EVA) matrix and exfoliated EVA/CRG–PPSPB nanocomposites are formed. The results from thermogravimetric analysis (TGA) and cone calorimeter tests indicate that CRG–PPSPB improve thermal stability and reduce obviously the flammability (including peak heat release rate (PHRR), total heat release (THR), average mass loss rate (AMLR), etc.) of EVA. Compared with pure EVA resin, the PHRR of the EVA/CRG–PPSPB nanocomposites filled with 1 wt% CRG–PPSPB is reduced by about 56%. The SEM images show that a compact, dense and uniform intumescent char is formed for EVA/CRG–PPSPB nanocomposites after combustion. The functionalization of graphene by intumescent flame retardant PPSPB can improve both the dispersion of graphene sheets in the polymer matrix and flame retardancy of the nanocomposites. [Copyright &y& Elsevier]

Abstract: A novel flame retardant poly(vinyl alcohol) (PVA)/melamine polyphosphate (MPP)–graphene nanocomposite has been prepared by solvent blending. Results from X-ray diffraction (XRD) and transmission electron microscopy (TEM) suggest that an excellent dispersion of exfoliated graphene and MPP in the PVA matrix was achieved. The thermal and flammability properties of the nanocomposite were investigated using thermogravimetry, cone calorimetry, and flammability tests (UL 94 and LOI). The presence of both MPP and graphene in the polymer matrix led to an enhanced thermal stability and significantly reduced flammability for the nanocomposite. PVA composites filled with 10wt% MPP and 1wt% graphene (PVA/G1/MPP10) achieved the LOI value of 29.6 and UL-94 V0 grade. Compared to pure PVA, the peak heat release rate (PHRR) of PVA/G1/MPP10 is reduced by about 60%. Meanwhile, the mechanical properties of PVA/G1/MPP10 composites exhibit almost no deterioration compared with pure PVA. The morphology and composition of residues generated after cone calorimeter tests were investigated by scanning electronic microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The SEM images showed the compact and dense intumescent char jammed with graphene sheets was formed for PVA/G1/MPP10 during combustion. The results of XPS confirmed that carbon content of the char for PVA/G1/MPP10 is increased obviously by the combination effect of the flame retardant MPP and graphene. [Copyright &y& Elsevier]

Abstract: 2,4,8,10-Tetraoxa-3,9-diphosphaspiro[5.5]-undecane-3,9-dioxide-disubstitutio-acetamide-N,N-dimethyl-N-hexadecy-ammonium bromide (PDHAB) containing phosphorus–nitrogen structure was synthesized and characterized. A novel flame retardant, montmorillonite (Mt) modified by PDHAB (PDHAB-Mt), was prepared by ion-exchange of sodium montmorillonite (Na+-Mt) with PDHAB. The results of X-ray diffraction (XRD) indicated that PDHAB had intercalated with Na+-Mt and exfoliated LDPE/EVA/20% PDHAB-Mt nanocomposites had been obtained by polymer melt intercalation which was further supported by TEM. The flammability of LDPE/EVA/PDHAB-Mt nanocomposites was investigated by the cone calorimeter test. The results showed that the addition of flame retardant PDHAB-Mt enhanced the flame retardancy of LDPE/EVA blend significantly. The results of SEM and TEM indicated that PDHAB-Mt can achieve better dispersion in the chars after combustion and the intumescent char is formed for LDPE/EVA/PDHAB-Mt nanocomposites after combustion. It is found that the char structure plays an important role for PDHAB-Mt in LDPE/EVA blend. The flame retardancy of LDPE/EVA blend was also significantly improved by an addition of PDHAB-Mt in LDPE/EVA blend. [Copyright &y& Elsevier]

Abstract: The 2-(2-(5,5-dimethyl-1,3,2-dioxaphosphinyl-2-ylamino)ethy-amino)-N,N,N-triethyl-2-oxoethanaminium chloride (compound c ) containing phosphorus–nitrogen structure was synthesized and characterized. A novel intumescent flame retardant, namely montmorillonite (MMT) by modified with compound c ( c -MMT), was prepared by ion exchanging of the nanometer Na+-montmorillonite (Na-MMT) with compound c . Both FTIR and X-ray diffraction (XRD) indicated that compound c had intercalated with Na-MMT and exfoliated c -MMT/PU nanocomposites have obtained by in-situ polymerization. TEM results further support the formation of the exfoliated nanocomposites. The thermal stability and flammability of c -MMT/PU composites were investigated by thermogravimetric analysis (TGA) and cone calorimeter test respectively. The results showed that the addition of flame retardant c -MMT enhanced the thermal stability and flame retardancy of PU significantly. SEM results indicated that c -MMT can achieve better dispersion in the chars after combustion and the compact and dense intumescent char is formed for c -MMT/PU composites after combustion. It is found that the char structure plays an important role for c -MMT in PU resin. The thermal stability and flame retardancy of PU resin were also significantly improved by an addition of c -MMT in PU resin. [Copyright &y& Elsevier]

• A multifunctional graphene-based nano-additive (Mo/PN-rGO) has been prepared. • 1 wt% of Mo5/PN-rGO increases tensile strength and modulus of ABS by 28% and 58%, respectively. • 1 wt% of Mo5/PN-rGO increases the initial degradation temperature of ABS by 21 °C. • The addition of Mo5/PN-rGO significantly reduce the ignitability of ABS. • The peak heat release rate and peak smoke production rate are respectively reduced by 51% and 60%. Despite many important industrial applications, the acrylonitrile–butadienestyrene copolymer (ABS) suffers from an inherent flammability, extremely hampering its practical use. Current flame retardants can effectively reduce the flammability issue but give rise to degraded mechanical and thermal properties of ABS. To address this intractable challenge, a graphene-derived flame retardant (Mo5/PN-rGO) was designed by introducing the functional elements (phosphorus, nitrogen and molybdate) onto the graphene oxides nanosheets. The resultant ABS nanocomposite containing 1.0 wt% of Mo5/PN-rGO exhibits a 28% increase in the tensile strength and a 58% enhancement in the Young's modulus as compared to the ABS host. Furthermore, the glass transition temperature (T g) increases by ca. 12 °C while the onset thermal decomposition temperature is significantly delayed by ca. 21 °C. In addition, the final ABS nanomaterial shows a 20% reduction in the total heat release and a 45% decrease in the total smoke production in comparison to the ABS bulk. This work paves a new way for the creation of high-performance flame retardants towards advanced flame-retardant polymer nanocomposites with expandable industrial applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multifunctional P/Ni-doped g-C 3 N 4 (Ni-P-C 3 N 4) nanoflakes were synthesized. • Ni-P-C 3 N 4 can be homogeneously dispersed in ABS by simple melt-blending. • Ni-P-C 3 N 4 endowed ABS with enhanced thermal stability and mechanical strength. • Ni-P-C 3 N 4 significantly improved the flame retardancy and smoke suppression of ABS. The ubiquitous application of highly flammable acrylonitrile–butadienestyrene (ABS) resin has brought great fire threat to human and environment. Unfortunately, current flame retardants often improve flame retardancy but reduce mechanical and thermal properties, seriously affecting their practical application. We herein reported novel multifunctional, high-efficiency, phosphorus and nickel co-doped graphitic carbon nitride (Ni-P-C 3 N 4) nanoflakes to address the trade-off between flame retardancy and mechanical/thermal properties. The addition of 2.0wt% of Ni-P-C 3 N 4 increased the initial degradation temperature and tensile strength of ABS composite (ABS/Ni-P-CN2) by 15 °C and 24.3% relative to virgin ABS, indicating its positive effect on thermal and mechanical properties. Compared with ABS, ABS/Ni-P-CN2 exhibited a notable increase in time to ignition, along with 32.4% and 33.8% reductions in peak heat release rate (PHRR) and peak smoke production rate (PSPR), demonstrating excellent anti-ignition, flame-retardant and smoke-suppressive performances. The increased fire safety was mainly due to the physical barrier effect of g-C 3 N 4 nanosheets and the catalytic charring effect of P and Ni. This work offers a novel design strategy to create multifunctional flame retardants for fabricating fire-safe polymer composites with superior thermal and mechanical properties, holding great potential in industries. [ABSTRACT FROM AUTHOR]

Phosphoramides, as a kind of high-efficient fire retardants, have been designed in many structures and endowed exceptional fire retardancy to polylactide (PLA). However, due to ignorance of the structure-property correlation, the effect of phosphoramides' structure on the fire retardancy and mechanical properties of PLA is still unclear. Herein, a series of biobased phosphoramides (phosphoramide (V1), linear polyphosphoramide (V2) and hyperbranched polyphosphamide (V3)) were designed and incorporated into PLA, and the structural effect of phosphoramides on the fire-retardant and mechanical properties of PLA was deeply researched. Among three kinds of phosphoramides, the hyperbranched polyphosphoramide is more effective than the corresponding linear polyphosphoramide and phosphoramide in improving the fire-retardant and anti-dripping properties of PLA, and only linear polyphosphoramide shows a positive effect in the mechanical strength of PLA. This work provides a feasible strategy for creating mechanically robust and fire-retardant polymer composites by molecularly tailoring the structure of fire retardants and uncovering their structure-property relationship. [Display omitted] • The structure-property correlation of PLA/phosphoramides was unveiled. • Hyperbranched polyphosphoramide shows the best performance in fire retardancy and anti-dripping behaviors of PLA. • Linear polyphosphoramide can simultaneously improve the tensile strength, elastic modulus and fire retardancy of PLA. [ABSTRACT FROM AUTHOR]

In this work, we found a very effective method to adjust the polarity of the fillers to promote its good dispersion in matrix by using an organic-solvent-free assembling strategy. With the coating of polyethylenimine-decorated graphene oxide (GO-PEI), the as-prepared biobased core-shell graphene oxide hybrid (BCSGOH) can distribute more homogeneously in the polylactide (PLA) matrix, compared with the bio-derived core-shell flame retardant (CSFR) with higher polarity. The polarity analysis of BCSGOH, CSFR and PLA indicated that the polarity of BCSGOH had a better match with that of PLA, and the interfacial tension (0.8 mN/m) between BCSGOH and PLA was much lower than that (12.0 mN/m) between CSFR and PLA. Consequently, the better flame retardancy, impact toughness and UV-shielding properties of PLA/BCSGOH composites were achieved. 6 wt% of BCSGOH endowed PLA with the best comprehensive properties, such as the UL94 V-0 rating, the limiting oxygen index (LOI) of 30.0%, and notched impact strength of 12.38 kJ/m2. Hence, this work offers a conducive, facile and green strategy to create high-performance fire-safe bioplastics. [Display omitted] • A surface-nanoengineered biobased core-shell structured fire retardant, BCSGOH, is prepared. • BCSGOH is uniformly dispersed in the PLA matrix because of a low interfacial tension. • 6 wt% BCSGOH enables PLA to achieve a desirable UL-94 V-0 rating. • The addition of BCSGOH leads to a 59% increase in the impact toughness of PLA. • The resultant fire-retardant PLA exhibits an improved UV-resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multifunctional MXene-based hybrid (Zr-MXene) has been prepared. • 1 wt% of Zr-MXene increases ductility and toughness of TPU by 33% and 88%, respectively. • 1 wt% of Zr-MXene increases the tensile strength and fatigue resistance of TPU. • The addition of Zr-MXene significantly reduce the flammability of TPU. • The peak heat release rate and peak smoke production rate are respectively reduced by 63% and 56%. Thermoplastic polyurethane (TPU) features many important industrial applications, but intrinsic flammability extremely impedes its practical applications. Current fire-retardant strategies often lead to improved flame retardancy but reduced mechanical properties (strength, ductility, and toughness). Hence, to date it has been unsuccessful to design advanced TPU materials that are strong, stretchable, tough, fatigue-and fire-resistant to meet increasing performance portfolio requirements. Here, we report a hybridized fire retardant (Zr-MXene) by in situ facilely loading zirconium amino-tris-(methylenephosphonate) (Zr-AMP) onto the titanium carbide (MXene) surface. Our results show that with 1 wt% of Zr-MXene, the resultant TPU nanocomposites demonstrate a record break strain (2060%) and toughness (316 MJ/m3) to date, in addition to increased tensile strength by 43.4% and improved fatigue resistance relative to the TPU matrix, because of favorable interfacial hydrogen-bonding. Moreover, the resultant TPU material exhibit significantly reduced flammability as a result of the combined physical barrier, catalytical carbonization and diluting effects of Zr-MXene. This work provides a promising strategy for the creation of multifunctional MXene and its polymeric nanocomposites, which hold great promise for many industrial applications. [ABSTRACT FROM AUTHOR]

The creation of high-performance polylactic acid (PLA) materials combining excellent mechanical robustness and flame-retardant performances are essential to meet demanding performances requirements for their practical applications in industry. Despite encouraging advances, current strategies by introducing toughening agents and flame retardants usually show compromised mechanical strength/ductility because of the irrational interphase reaction design of multi-component polymer blends. To date it remains challenging to robust and flame-retardant PLA via controlling interphase reactions. We, herein, report the rational design of mechanically robust and flame-retardant PLA by in situ manipulating interphase reactions between PLA, epoxidized soybean oil (ESO), a biobased and inexpensive toughening agent, and ammonia polyphosphate (APP), an effective eco-friendly flame retardant. We show that in addition to a high tensile strength of 42.0 MPa, as-designed PLA/ESO/APP ternary blend exhibits a high extensibility of 165% and a fracture toughness as high as 46 MJ/m3, which are respectively 21 and 14 folds of that of the bulk PLA. Meanwhile, a desired V-0 rating and a high limited oxygen index of 30.2% are achieved. Such outstanding performance portfolios are enabled by the rational manipulation of interphase reactions, leading to the in situ formation of favorable phase structures. This work offers an innovative methodology for facilely and massively creating high-performance multi-component polymer blends by tailoring interphase reactions, and contributes to expanding the extensive applications of PLA. Image 1 • Advanced PLA/ESO/APP ternary blends have been rationally designed via manipulating interphase reactions. • As-designed PLA/ESO/APP blend exhibits a large extensibility of 165% and a fracture toughness as high as 46 MJ/m3. • The PLA/ESO/APP ternary blend retains a high tensile strength of 42.0 MPa. • The PLA/ESO/APP blend can pass a V-0 rating in addition to showing a high LOI of 30.2%. [ABSTRACT FROM AUTHOR]