Search

[Display omitted] • A multifunctional small molecule (HCPA) has been prepared. • The presence of HCPA endowed PVA with a nanostructure within the continuous matrix. • 5 wt% of HCPA endows PVA with a self-extinguishing behavior. • 5 wt% of HCPA increases tensile strength of PVA by 47% and toughness by 370%. • The PVA/HCPA composites exhibit a water-trigged healing efficiency over 90%. The combination of high fire retardancy, high strength, and great toughness as well as good healability is essential for successful real-world applications of polymeric materials in the fields of packaging, electronics & electrics, and optical devices. To date, there have been few successes in achieving such performance portfolios in polymers due to their different and even mutually exclusive governing mechanisms. Inspired by the nanoconfinement effect that governs the unique mechanical properties of spider silk, we, herein, rationally design a multifunctional small molecule, HCPA, that can serve as a fire retardant and hydrogen-bond crosslinker for poly(vinyl alcohol) (PVA). Benefiting from the dual-phase fire-retardancy effect and the dynamic cross-linking effect, the addition of 5.0 wt% of HCPA enables PVA to achieve a desired self-extinguishment in combination with a high tensile strength of 133 MPa and a toughness of 112 MJ/m3. In addition, the as-prepared polymer material exhibits a high healing efficiency of over 90% (based on strength) if triggered by water. This proof-of-concept opens numerous opportunities for the creation of self-extinguishing, strong, tough, and self-healing polymers for many high-end applications in the above-mentioned industries. [ABSTRACT FROM AUTHOR]

Biodegradable polymeric materials with high strength and outstanding toughness are necessary for real‐world applications in the fields of electronics, electrics, and packaging. Unfortunately, such performance portfolios in polymers remain challenging to achieve due to their different governing mechanisms. Inspired by the hydrogen‐bond (H‐bond) cross‐linking structure of spider silk, herein, strong and tough poly(vinyl alcohol) (PVA) composites with β‐cyclodextrin as a cross‐linker are developed. Benefiting from the H‐bond cross‐linking effect, the addition of 1.0 wt% of β‐cyclodextrin enables PVA to achieve a high tensile strength of 136.5 MPa, and a high elastic modulus of 3.0 GPa, in combination with a good toughness of 82.1 MJ m−3. In addition, the presence of β‐cyclodextrin improves the biodegradability of PVA composite by decreasing its crystalline size. Furthermore, PVA/β‐cyclodextrin composite combined with MXene has great potential as a sensor material for humidity and strain detection. This proof‐of‐concept opens numerous opportunities to create strong, tough, and biodegradable polymers for packing and sensing applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multifunctional heterostructure additive (CuP-MXene) has been prepared. • 5 wt% of CuP-MXene increases antibacterial efficiency of EP up to 99.99%. • 5 wt% of CuP-MXene endows EP with a self-extinguishing behavior. • The presence of CuP-MXene improves mechanical strength and impact toughness of EP. • The peak heat release rate and total smoke release are reduced by 64.4% and 40.5%. The ongoing Covid-19 pandemic has raised the need for urgent antibacterial requirements for many commercially important polymers, e.g., Epoxy resins (EPs). Meanwhile, intrinsic flammability and poor impact toughness are two big obstacles that greatly impede the practical applications of EPs. Hence, it has been imperative but highly challenging to create advanced EPs combining satisfactory antibacterial, fire-retardant and mechanically robust performances so far. Here, we report a reactive multifunctional heterostructure, copper-organophosphate-MXene (CuP-MXene) by rational design. Our results show that with 5.0 wt% of CuP-MXene, in addition to achieving a high antibacterial efficiency above 99.9%, the resultant EP nanocomposite exhibits satisfactory flame retardancy (UL-94 V-0 rating, peak heat release rate decreased by 64.4%) and improved mechanical properties (tensile strength, elastic modulus and impact strength increased by 31.7%, 38.9%, and 25.0%, respectively) relative to virgin EP, outperforming its previous counterparts. Such a desirable performance portfolio arises from multiple synergistic effects between CuP and MXene. This work provides a general strategy for the design of multifunctional nanoadditives and advanced functional polymers, and creates more opportunities for industrial applications of EP in the areas of coatings, medical devices and furniture. [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]

Novel iron hexamethylenediaminetetrakis-(methylenephosphonate) (Fe-HDTMP)-reduced graphene oxide (Fe-rGO) hybrids were prepared by in situ immobilization of Fe-HDTMP nanoparticles and the reduction of graphene oxide via a hydrothermal strategy. Fe-rGO modification of epoxy resin (EP) improved mechanical properties, flame retardancy, smoke suppression, and thermal stability by combination with flame retardant elements (i.e. Fe, N, and P) and graphene nanoplatelets. The incorporation of 1% Fe-rGO increased the impact strength and storage modulus of EP by 19.2, and 27.9%, respectively. Additionally, the incorporation of 5% Fe-rGO helped EP/5Fe-rGO achieve UL-94 V0 rating with a limiting oxygen index of 30.5%. Compared to untreated EP, the modified EP exhibited 68.2% lower release of total smoke, 54.5% decreased peak CO production rate, 66.3% lower total heat release, and 47.7% reduced peak heat release rate of EP/5Fe-rGO. In addition, the glass-transition temperature of EP/Fe-rGO nanocomposite was maintained at a high level. The improved fire safety performance of EP/2Fe-rGO nanocomposite was due to the catalyzing carbonization effect, the release of inert compounds of Fe-rGO in condensed and gas phases, and the barrier effect of graphene. [ABSTRACT FROM AUTHOR]

• m-SiO 2 @Zn-AMP spheres were synthesized via a self-assembly process. • m-SiO 2 @Zn-AMP exerts good mechanical enhancement in EP. • m-SiO 2 @Zn-AMP shows better flame retardancy and smoke suppression in EP. Mesoporous silica@nano-zinc amino- tris -(methylenephosphonate) (m-SiO 2 @Zn-AMP) spheres were synthesized via a self-assembly process to integrate the outstanding flame retardancy, thermal stability, and mechanical properties of these materials. The results indicated that nano Zn-AMP particles were successfully deposited on the surface of m-SiO 2 through electrostatic interactions. The prepared m-SiO 2 @Zn-AMP was utilized to improve the flame retardancy, smoke suppression, and mechanical properties of epoxy resin (EP). The storage modulus, impact, and tensile strengths of the EP with 1% m-SiO 2 @Zn-AMP (sample EP/1m-SiO 2 @Zn-AMP) were increased by 29.9, 50.0, and 23.5 %, respectively, relative to the values for untreated EP. The presence of multiple flame retardant elements (i.e. Si, P, N, and Zn) in the mesoporous spheres led to the formation of high yields of compact char residues and the release of inert substance during combustion, for high flame retardancy and efficient smoke suppression in the condensed and gaseous phase. The EP/5m-SiO 2 @Zn-AMP sample achieved a V0 rating in a vertical UL-94 test. Compared to untreated EP, the amount of total smoke released and the peak CO production rate of EP/5m-SiO 2 @Zn-AMP were reduced by 53.1 and 61.5 %, respectively. Additionally, the total heat release and peak heat release rate of EP/5m-SiO 2 @Zn-AMP were decreased by 45.2 and 57.8 %, respectively. [ABSTRACT FROM AUTHOR]

Recently, soaring developments in microelectronics raise an urgent demand for thermal management materials to tackle their "overheating" concerns. Polymer nanocomposites are promising candidates but often suffer from their inability of mass production, high‐cost, poor mechanical robustness, and even flammability. Hence, it is desirable to scalably fabricate low‐cost, robust polymeric nanocomposites that are highly thermally conductive and fire‐retardant to ensure safe and efficient thermal management. Herein, the scalable production of nacre‐like anisotropic nanocomposite films using the layer‐by‐layer assembly of phenylphosphonic acid@graphene nanoplatelets (PPA@GNPs)‐poly(vinyl alcohol) (PVA) layer and GNPs layers, is demonstrated. The PPA serves as interfacial modifiers and fire retardants for flammable PVA (film‐forming agent) and GNPs (inexpensive conductive nanofillers) via hydrogen‐bonding and π–π stacking. The resultant nanocomposite exhibits a high flexibility, high tensile strength of 259 MPa, and an ultrahigh in‐plane thermal conductivity of 82.4 W m‐1 K‐1, making it effectively cool smartphone and high‐power light emitting diode modules, outperforming commercial tinfoil counterparts. Moreover, the as‐designed nanocomposites are intrinsically fire‐retardant and can shield electromagnetic interference. This work offers a general strategy for mass production of thermally conductive nanocomposites holding great promise as thermal management materials in electronic, military, and aerospace fields. [ABSTRACT FROM AUTHOR]

Recently, soaring developments in microelectronics raise an urgent demand for thermal management materials to tackle their "overheating" concerns. Polymer nanocomposites are promising candidates but often suffer from their inability of mass production, high‐cost, poor mechanical robustness, and even flammability. Hence, it is desirable to scalably fabricate low‐cost, robust polymeric nanocomposites that are highly thermally conductive and fire‐retardant to ensure safe and efficient thermal management. Herein, the scalable production of nacre‐like anisotropic nanocomposite films using the layer‐by‐layer assembly of phenylphosphonic acid@graphene nanoplatelets (PPA@GNPs)‐poly(vinyl alcohol) (PVA) layer and GNPs layers, is demonstrated. The PPA serves as interfacial modifiers and fire retardants for flammable PVA (film‐forming agent) and GNPs (inexpensive conductive nanofillers) via hydrogen‐bonding and π–π stacking. The resultant nanocomposite exhibits a high flexibility, high tensile strength of 259 MPa, and an ultrahigh in‐plane thermal conductivity of 82.4 W m‐1 K‐1, making it effectively cool smartphone and high‐power light emitting diode modules, outperforming commercial tinfoil counterparts. Moreover, the as‐designed nanocomposites are intrinsically fire‐retardant and can shield electromagnetic interference. This work offers a general strategy for mass production of thermally conductive nanocomposites holding great promise as thermal management materials in electronic, military, and aerospace fields. [ABSTRACT FROM AUTHOR]

A novel phosphorus-nitrogen flame retardant, nano zirconium amino- tris -(methylenephosphonate) (Zr-AMP), successfully synthesized by allowing amino trimethylene phosphonic acid (AMP) to react with ZrOCl·8H 2 O, was incorporated into rigid polyurethane (RPU) foam with expandable graphite (EG) to prepare flame retarded composites. A synergistic effect between nano Zr-AMP and EG on flame retarded and physical-mechanical properties of RPU foam was observed. The RPU foam containing 3 wt% nano Zr-AMP and 12 wt% EG (RPU/12EG/3Zr-AMP) achieved a UL-94 V0 rating with a limiting oxygen index of 30.5%. RPU/12EG/3Zr-AMP showed a 74.4% reduction of peak heat release rate relative to untreated RPU foam. Furthermore, RPU/12EG/3Zr-AMP possessed lower thermal conductivity compared with the RPU foam with 15 wt% EG (RPU/15EG), while the compressive strength of RPU/12EG/3Zr-AMP was enhanced by 40% compared with the one of the latter. The thermogravimetric analysis showed that the simultaneous addition of nano Zr-AMP and EG had a positive impact on improving the char yield and thermal stability of RPU foam. Image 1 • Zr-AMP was synthesized and evaluated as a novel phosphorus and nitrogen-containing flame retardant for RPU foam. • Zr-AMP nanoparticles improved compressive strength, thermal stability and flame retardancy of RPU foam. • Zr-AMP nanoparticles and EG showed good synergistic effect on flame-retardant and physico-mechanical properties in RPU foam. [ABSTRACT FROM AUTHOR]