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Journal of Colloid and Interface Science Jun 2024Enhancing the flame retardancy of epoxy (EP) resins typically entailed a trade-off with other physical properties. Herein, hyperbranched poly(amidoamine) (HPAA) and...
Enhancing the flame retardancy of epoxy (EP) resins typically entailed a trade-off with other physical properties. Herein, hyperbranched poly(amidoamine) (HPAA) and phytic acid (PA) were used to functionalize graphene oxide (GO) via electrostatic self-assembly in water to prepare a phosphorus-nitrogen functionalized graphene oxide nanosheet (PN-GOs), which could be utilized as high efficient flame-retardant additive of epoxy resin without sacrificing other properties. The PN-GOs demonstrated improved dispersion and compatibility within the EP matrix, which resulted in significant concurrent enhancements in both the mechanical performance and flame-retardant properties of the PN-GOs/EP nanocomposites over virgin EP. Notably, the incorporation of just 1.0 wt% PN-GOs yielded a 20.4, 6.4 and 42.7 % increases in flexural strength, flexural modulus and impact strength for the PN-GOs/EP nanocomposites, respectively. Furthermore, simultaneous reductions were achieved in the peak heat release rate (pHRR) by 60.0 %, total smoke production (TSP) by 43.0 %, peak CO production rate (pCOP) by 57.9 %, and peak CO production rate (pCOP) by 63.9 %. This study presented a facile method for the design of GO-based nano flame retardants, expanding their application potential in polymer-matrix composites.
PubMed: 38852349
DOI: 10.1016/j.jcis.2024.06.005 -
Chemical Science Jun 2024Hard carbon (HC) is one of the most promising anode materials for sodium-ion batteries (SIBs) due to its cost-effectiveness and low-voltage plateau capacity. Heteroatom...
Hard carbon (HC) is one of the most promising anode materials for sodium-ion batteries (SIBs) due to its cost-effectiveness and low-voltage plateau capacity. Heteroatom doping is considered as an effective strategy to improve the sodium storage capacity of HC. However, most of the previous heteroatom doping strategies are performed at a relatively low temperature, which could not be utilized to raise the low-voltage plateau capacity. Moreover, extra doping of heteroatoms could create new defects, leading to a low initial coulombic efficiency (ICE). Herein, we propose a repair strategy based on doping a trace amount of P to achieve a high capacity along with a high ICE. By employing the cross-linked interaction between glucose and phytic acid to achieve the P doped spherical hard carbon, the obtained PHC-0.2 possesses a large interlayer space that facilitates Na storage and transportation. In addition, doping a suitable amount of P could repair some defects in carbon layers. When used as an anode material for SIBs, the PHC-0.2 exhibits an enhanced reversible capacity of 343 mA h g at 20 mA g with a high ICE of 92%. Full cells consisting of a PHC-0.2 anode and a NaFeMn[Fe(CN)] cathode exhibited an average potential of 3.1 V with an initial discharge capacity of 255 mA h g and an ICE of 85%. The full cell displays excellent cycling stability with a capacity retention of 80.3% after 170 cycles. This method is simple and low-cost, which can be extended to other energy storage materials.
PubMed: 38846387
DOI: 10.1039/d4sc01395f -
Materials Horizons Jun 2024Expanding the detection information of wearable smart devices in applications has practical implications for their use in daily life and healthcare. Damage and breakage...
Expanding the detection information of wearable smart devices in applications has practical implications for their use in daily life and healthcare. Damage and breakage caused by mechanical injuries and continuous use are unavoidable for polymer matrices so self-healing properties are expected to be conferred on flexible sensors to extend their life and durability. In addition, a good linearity of relative resistance change strain (gauge factor, GF) facilitates the streamlined conversion of electrical signals to 3D information of human motion, whereas existing works on sensors neglect the quantitative analysis of signals. This letter reports a self-healable flexible electronic sensor based on hydrogen bonding and electrostatic interaction between maleic acid-grafted natural rubber (MNR), polyaniline (PANI), and phytic acid (PA). MNR is the flexible matrix and the template for aniline (ANI) polymerization, and PA acts as the dopant and crosslinking agent. The MNR-PANI-PA sensor shows easy self-healing at room temperature, enhanced mechanical behaviour (∼2.5 MPa, 1000% strain), and excellent linearity (GF of 13.8 over 250% strain and GF of 32.0 over 250-100% strain). Due to the highly linear relationship between Δ/ and bending angle, the electrical signals of human limb movement can output relevant information on bending angle and frequency. By constructing a sensing array, changes in the position and magnitude of applied pressure could also be detected in real-time. Based on these advantages, the MNR-PANI-PA composite sensor is expected to have potential applications in health monitoring, body motion detection, and electronic skins.
PubMed: 38836844
DOI: 10.1039/d4mh00448e -
Biomacromolecules Jun 2024Polylactide is a high potential polymer that can satisfy the growing demand for sustainable and lightweight materials in construction, packaging, and structural...
Layer-over-Layer Electrostatic Self-Assembly of Bioresourced Compounds in Thermoreversible Polylactide Gels as an Effective Approach to Enhance the Flame Retardancy of Aerogels.
Polylactide is a high potential polymer that can satisfy the growing demand for sustainable and lightweight materials in construction, packaging, and structural applications. However, their high flammability poses a serious concern. Herein, with the aid of solvent exchange and noncovalent interactions, poly(l-lactide) (PLLA) thermoreversible gel was modified with sodium alginate (SA), chitosan (CS), and phytic acid (PA) via a layer-over-layer approach. Freeze-drying of the modified hydrogel furnished a highly flame retardant aerogel with shape stability and no shrinkage. The modified PLLA aerogel (PLLA@SA@CS@PA) exhibited self-extinguishment of flame, the highest limiting oxygen index of any porous polylactide (∼32%), and a tremendous reduction in flammability parameters such as the heat release rate, heat release capacity, total heat release, etc. A comprehensive mechanism of flame retardancy was proposed. This work provides a sustainable strategy for the flame retardant modification of semicrystalline polymer-based aerogels and is expected to expand their practical applications in various industrial sectors.
PubMed: 38836359
DOI: 10.1021/acs.biomac.4c00577 -
Clinical, Cosmetic and Investigational... 2024This study aimed to evaluate the bond strength of a universal adhesive to dentin (μTBS) using different time periods of airborne particle abrasion (APA) and two types...
OBJECTIVE
This study aimed to evaluate the bond strength of a universal adhesive to dentin (μTBS) using different time periods of airborne particle abrasion (APA) and two types of acid etching.
METHODS
Seventy-two human third molars were divided into 9 groups (n=8) according to dentin pretreatment: APA duration (0, 5, or 10s) and acid etching (no acid - NA, 37% phosphoric acid - PhoA, or 1% phytic acid - PhyA). APA was performed at a 0.5 cm distance and air pressure of 60 psi using 50 μm aluminum oxide particles. Afterwards, two coats of Single Bond Universal adhesive (3M) were applied to the dentin surface. Composite blocks were built using the incremental technique, sectioned into 1×1 mm slices and subjected to microtensile bond strength (μTBS) testing. Fracture patterns and surface topography of each dentinal pretreatment were evaluated using a Scanning electron microscope (SEM). Bond strength data were analyzed using two-way ANOVA and Bonferroni tests.
RESULTS
The group that received pretreatment with 5s APA and PhoA presented higher μTBS values among all groups, which was statistically different when compared with the PhoA, 10APA+PhoA, and 5APA+PhyA groups. PhyA did not significantly influence the bond strength of the air-abraded groups. Finally, adhesive failure was considered the predominant failure in all groups.
CONCLUSION
Dentin pretreated by airborne particle abrasion using aluminum oxide demonstrated an increase in bond strength when abraded for 5 seconds and conditioned with phosphoric acid in a universal adhesive system.
PubMed: 38835853
DOI: 10.2147/CCIDE.S456826 -
ACS Macro Letters Jun 2024Latent curing agents are essential in the formulation of one-component epoxy resins, yet they are seldom derived from fully biobased chemicals. In the present work, a...
Latent curing agents are essential in the formulation of one-component epoxy resins, yet they are seldom derived from fully biobased chemicals. In the present work, a fully biobased latent curing agent for epoxy resins (BIMPA) was produced by synthesizing an ionic complex of lignin-derived triaryl-imidazole (BIM) and phytic acid (PA). Benefiting from the synergistic effect of BIM and PA, the one-component epoxy resin, composed of BIMPA and commercially available E51, exhibits a storage stability of over 90 days. Upon heating, the ionic complex undergoes decomposition, liberating the active imidazole to cure the precursor. The resulting epoxy resins exhibited a flexural modulus of 3.09 GPa, a flexural strength of 107.47 MPa, a notched izod impact strength of 2.47 kJ/m, and a shear strength of 41.02 MPa. The outcome can provide an effective supplement for the development of biobased epoxy resins.
PubMed: 38832802
DOI: 10.1021/acsmacrolett.4c00247 -
Carbohydrate Polymers Sep 2024Efficient removal of uranium from radioactive wastewater is crucial for both environmental protection and sustainable development of nuclear energy. However, selectively...
Efficient removal of uranium from radioactive wastewater is crucial for both environmental protection and sustainable development of nuclear energy. However, selectively extracting uranium from acidic wastewater remains a significant challenge. Here we present a phytic acid-functionalized polyamidoxime/alginate hydrogel (PAG) via a facile one-step hydrothermal reaction. The PAG, leveraging the robust binding affinity of phytic acid and the selective coordination of amidoxime for U(VI), exhibited high efficiency and selectivity in adsorbing U(VI) from acidic uranium-containing wastewater. At pH 2.50, U(VI) adsorption equilibrium was achieved within 60 min, showcasing a maximum theoretical adsorption capacity of 218.34 mg/g. Additionally, the PAG demonstrated excellent reusability, maintaining a uranium removal rate exceeding 90 % over five adsorption-desorption cycles. Remarkably, the as-synthesized PAG removed 94.1 % of U(VI) from actual acidic uranium-contaminated groundwater with excellent anti-interference performance, reducing U(VI) concentration from 272.0 μg/L to 16.1 μg/L and making it meet the WHO drinking water standards (30 μg/L). The adsorption mechanism was elucidated through XPS and DFT calculation, revealing that the uranyl ion primarily coordinated with phosphate and amidoxime groups on phytic acid and polyamidoxime, respectively. These findings underscore the promising potential of PAG hydrogel for addressing acidic uranium-containing wastewater from uranium mining and metallurgy.
PubMed: 38823934
DOI: 10.1016/j.carbpol.2024.122283 -
International Journal of Biological... May 2024In the field of building energy conservation, the development of biodegradable biomass aerogels with excellent mechanical performance, flame retardancy and thermal...
In the field of building energy conservation, the development of biodegradable biomass aerogels with excellent mechanical performance, flame retardancy and thermal insulation properties is of particular importance. Here, a directional freeze-drying method was used for fabricating composite sodium alginate (SA) aerogels containing functionalized ammonium polyphosphate (APP) flame retardant. In particular, APP was coated with melamine (MEL) and phytic acid (PA) by a supramolecular assembly process. Through optimizing the flame retardant addition, the SA-20 AMP sample exhibited excellent flame retardant and thermal insulation properties, with the limiting oxygen index of 38.2 % and the UL-94 rating of V-0. Such aerogels with anisotropic morphology demonstrated a low thermal conductivity of 0.0288 (W/m·K) in the radial direction (perpendicular to the lamellar structure). In addition, as-obtained aerogels displayed remarkable water stability and mechanical properties, indicating significant potential for practical applications.
PubMed: 38823751
DOI: 10.1016/j.ijbiomac.2024.132643 -
International Journal of Biological... Jun 2024Smart textiles with flame retardant and fire-warning functions have received more and more attention. However, improving the fire-warning response sensitivity and...
Smart textiles with flame retardant and fire-warning functions have received more and more attention. However, improving the fire-warning response sensitivity and long-term responsiveness of the smart textiles is a top priority. In this research, flame retardant and fire-warning cotton fabrics were prepared by layer-by-layer assembly composite coating consisting of bio-based flame retardants composed of chitosan (CS) and phytic acid (PA) and carbon-based nanomaterials composed of carbon nanotubes (CNTs) and graphene oxide (GO). The PA-GO/CS-CNTs coated cotton fabric showed excellent flame retardancy with a limiting oxygen index (LOI) value of 31 %, and the coated fabrics could self-extinguish rapidly when the flame was removed. The fire hazard of the coated fabric was significantly reduced by reducing the 45.77 % of peak heat release rate, 29.69 % of total heat release and 81.9 % of total smoke production. The PA-GO/CS-CNTs coated cotton fabric showed ultra-fast fire warning response with the response time of 1.0 s. And the fire-warning response time of the coated cotton fabric could last longer than 600 s revealing it possessed the continuous fire warning response property. This research provides a new strategy to prepare the smart fireproof textiles with flame retardant and fire-warning functions to broaden its application in early fire-warning.
Topics: Flame Retardants; Cotton Fiber; Chitosan; Graphite; Nanotubes, Carbon; Textiles; Fires; Phytic Acid
PubMed: 38821804
DOI: 10.1016/j.ijbiomac.2024.132673 -
Saudi Journal of Biological Sciences Jul 2024Phytate content in feed ingredients can negatively impact digestibility and palatability. To address this issue, it is necessary to study microbes capable of breaking...
Phytate content in feed ingredients can negatively impact digestibility and palatability. To address this issue, it is necessary to study microbes capable of breaking down phytate content. This study aimed to isolate and characterize phytase-producing bacteria from decaying materials rich in phytic acid. The research was conducted in several stages. The first stage involved isolating phytase-producing bacteria from the acidification of using growth media containing Na-phytate. Bacterial isolates that produced clear zones were then tested for their activity and ability to produce several enzymes, specifically phytase, cellulase, and protease. The next step was to test the morphological characteristics of the bacterial isolate. The final stage of bacterial identification consisted of DNA isolation, followed by PCR amplification of the 16S rRNA gene, DNA sequence homology analysis, and construction of a phylogenetic tree. Based on research, three isolates were found to produce clear phytase zones: isolates R5 (20.3 mm), R7 (16.1 mm) and R8 (31.7 mm). All isolates were able to produce the enzymes phytase (5.45-6.54 U/ml), cellulase (2.60-2.92 U/ml), and protease (22.2-23.4 U/ml). Metagenomic testing identified isolate R7 and R8 as and isolate R5 as . The isolation and characterization of phytase-producing bacteria from acidification resulted in the identification of two promising candidates that can be applied as sources of phytase producers. Phytase-producing bacteria can be utilized to improve digestibility and palatability in animal feed.
PubMed: 38813263
DOI: 10.1016/j.sjbs.2024.104006