Aromatic amines was produced from PF resins with 14.2 C% yield and 58% selectivity.
Co-pyrolysis effectively enhanced aromatic amines yield by 32.2% to 11.8 C%.
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•Aromatic amines were ...produced from PF resins via catalytic pyrolysis with NH3.•Commercial HZSM-5-3 (Si/Al of 80) zeolites performed high actively.•Acidity of catalyst played a key role for the animation of polymers with NH3.•Co-pyrolysis effectively enhanced aromatic amines yield by 32.2%.•Synergy between PF resins and lignin increased simple phenols production.
Aromatic amines could be produced from organic wastes via catalytic pyrolysis with ammonia that served not only as a carrier gas but also as a reactant. Aromatic amines of 14.2 C% with selectivity of 57.6% were obtained from phenol-formaldehyde resins via pyrolysis over commercial HZSM-5-3 zeolite (Si/Al ratio of 80) catalyst at 650 °C. Significant synergetic effects have been observed when lignin was added, which improved aromatic amines yield by 32.2% to 11.8 C% at the mixing weight ratio of lignin to PF resins of 1:1. HZSM-5-3 was slightly deactivated after 3 cycles with acid sites loss. Catalytic co-pyrolysis of plastics and biomass wastes is a fast and effective method to produce aromatic amines.
A uniform dispersion of reactants is necessary to achieve a complete reaction involving multiple components. Utilizing a combination of infrared spectroscopy, thermal analysis and low field NMR, we ...have elucidated the role of three types of reactive plasticizers on the crosslinking reaction between hexamethylenetetramine and phenol formaldehyde resin. These two seemingly dissimilar reactants are responsible for the exceptionally high mechanical strength in a number of organic-inorganic composites. The efficiencies of the curing reaction and the achieved crosslinked structures are strongly dependent on the type of plasticizer employed. Infrared active vibrations are used to characterize the changing molecular structures of the individual reactants as a function of temperature. The T1 spin-lattice relaxation time measured using low field NMR is especially useful for the characterization of segmental dynamics of the chains in the formation of the extremely rigid crosslinked product. This study shows that the amount of crosslinking and the crosslinked structure can be very different for the three types of reactive plasticizers and also different in comparison to non-reactive plasticizers. We are also able to correlate the reactivity and functionality of the plasticizer to the crosslink density in the reacted product.
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Soft magnetic materials with an excellent performance are desired for functional applications. We present an innovative method for manufacturing the soft magnetic composites that may pave the way for ...magnetic cores with improved electromagnetic properties. In this paper, soft magnetic composites based on FeSi powder coated with the hybrid organic-inorganic coating composed of boron phenol-formaldehyde resin and Ni0.3Zn0.7Fe2O4 ferrite fibres were fabricated to investigate the effects of ferrite nanofibres on the structural and electromagnetic properties. A uniformity of hybrid organic-inorganic coating is reflected in a high value of the electrical resistivity. A low porosity and extraordinary high values of mechanical hardness and flexural strength were found in prepared soft magnetic composites.
•Ferrite nanofibres in SMC improve the structural and electromagnetic properties.•SMC samples show very high electrical resistivity.•Magnetization study reveals soft magnetic properties of all samples with ferrite nanofibres.
A reversible two-channel fluorescent nanocomposite with fluorescence resonance energy transfer (FRET) effect was designed for the development, analysis, and characterization of latent fingerprints ...(LFPs). For the construction of the FRET probe, a core of mesoporous silicas (MSNs) were used to encapsulate the organic dye rhodamine 6G (RhD-6) as an acceptor, while green-emitting monodisperse phenolic resin nanoparticles (PFR NPs) were selected as a donor. The up-conversion material (UC) of NaYF
4
:Yb,Er was synthesized using a simple hydrothermal method, and the MSNs-RhD-6/PFR (PRM) was electrostatically adsorbed onto the UC nanoparticles using a layer-by-layer method to obtain MSNs-RhD-6/PFR-UC (PMU). Compared to ordinary single-channel materials, PMU can be excited by different light sources (365 nm UV/980 nm laser) and its fluorescence can be reversibly switched between yellow and green, demonstrating excellent light reversibility. The PMU composites were successfully used to visualize and detect LFPs on various substrate surfaces using a simple powder coating method. Due to the existing FRET effect and dual-channel characteristics, this composite material displays excellent contrast, outperforming commercially available products for wider applicability. Even on complex backgrounds and after aging or washing treatments, it still clearly recognizes fingerprints in first-, second-, and third-level details, showing its great potential in latent fingerprint detection.
A reversible two-channel fluorescent nanocomposite with fluorescence resonance energy transfer (FRET) effect was designed for the development, analysis, and characterization of latent fingerprints (LFPs).
Carbon and iron composites have drawn much attention for their unique electromagnetic properties. In addition, nitrogen doping of carbon can effectively modulate the dielectric properties of carbon. ...Therefore, synthesis of N-doped carbon and iron composites is an alternative method for obtaining high-efficiency microwave absorption materials. In previous studies, the synthesis process was very complicated including multistep routes. In this work, N-doped carbon with embedded Fe/Fe
3
C was synthesized in-situ via pyrolysis of amino phenol formaldehyde resin (APF) scattered with Fe
2
O
3
nanoparticles (APF/Fe
2
O
3
), which was obtained through a simple hydrothermal process. During the heat-treatment process, the APF resin was converted into N-doped carbon, and simultaneously, the Fe
2
O
3
was reduced to iron nanoparticles. Then, inevitably, the iron nanoparticles reacted with carbon to form Fe
3
C at the interface between the iron particles and carbon. Taking advantage of multiple heterogenous interface, the interfacial polarization relaxation could be enhanced. Therefore, the N-doped carbon with embedded Fe/Fe
3
C particles displays microwave absorption with a maximum reflection loss of − 70 dB. Moreover, the effective absorption bandwidth (reflection loss of less than − 10 dB) reaches 6.02 GHz at a thickness of 2.13 mm. This study not only provides composites of N-doped carbon with embedded Fe/Fe
3
C particles with excellent stable microwave absorption but also offers a simple method for synthesizing N-doped carbon with embedded Fe/Fe
3
C particles.
Phenol formaldehyde (PF) resin capsules containing dicyclopentadiene (DCPD) as core materials are rationally designed and fabricated. The synthesis consists of preparation of polystyrene (PS) sphere, ...PF coating on PS sphere, followed by removal of PS core, amination modification and importing of DCPD. Solution phase switchable transport trough PF shell layer is key for the synthesis of DCDP@PF capsules. The resultant DCDP@PF capsules have a diameter of ∼500 nm, shell thickness of ∼50 nm, and core content of ∼45 wt%. The results show that DCDP@PF capsules have outstanding thermal stability with initial evaporation temperature (defined at 5% of weight loss), increased by ∼30 °C compared with that of pure DCPD, and good resistance to acetone. Preliminary results indicated that the prepared DCPD@PF capsules can effectively improve the mechanical properties of epoxy matrix as well as impart it self-healing properties. When 15 wt% DCPD@PF capsules were introduced into epoxy matrix, 81.4% increment in fracture toughness, 26.6% increment in tensiles strength and 91.8% recovery in fracture toughness can be obtained. This work provides a new insight into the investigation of the fabrication of self-healing capsules.
This research work investigated the physical and mechanical properties of particleboard panels bonded with maleated-lignin-phenol-formaldehyde (mLPF) resin. For this purpose, lignin was modified by ...maleic anhydride and then various contents of unmodified/modified lignin (30, 40 and 50 wt%) were added as a substitute for phenol in the phenol-formaldehyde (PF) resin synthesis. The properties of the synthesized resins were compared with those of an unmodified LPF and a control PF resin. The structure of the modified lignin was studied by FTIR, and the changes in curing behavior of the resins prepared were analyzed by DSC. The physicochemical properties of the synthesized resins (such as gel time, viscosity, solid content and density) and physical (water absorption) and mechanical properties (flexural properties, internal bond strength) of the prepared particleboard panels bonded with LPF resins were measured. The FTIR analysis indicated that, by treatment of lignin, the COOH, C–O and CC bonds increase while the content of O–H bond markedly decreases. The DSC analysis showed that curing of the mLPF resin occurred at a lower temperature than for the control PF resin and the unmodified lignin-phenol-formaldehyde (LPF) resins. The viscosity increased and the gel time was shortened by adding maleated lignin to the PF resin. The panels bonded with the modified lignin resins presented a lower formaldehyde emission, and a higher dimensional stability and mechanical strength than those bonded with the control PF resin and the unmodified lignin adhesive. Moreover, the mechanical strength and dimensional stability of the particleboard panels were significantly improved by increasing the resin content of maleated lignin from 0 to 50 wt%.
•For lithium-ion batteries, phosphorus-doped phenol formaldehyde resin is used as carbon source for the first time.•The doping of phosphorus increases the active sites of the material, and improves ...the Li+ diffusion coefficient.•The Si@C/P anode possesses an excellent discharge capacity of 1873 mAh g−1 at 1 A g−1 after 100 cycles.•Simple and convenient synthesis method.
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As one of the most promising electrode materials for lithium-ion batteries, silicon offers a high theoretical capacity, but it has been greatly limited by a volume expansion effect and the formation of unstable solid–electrolyte interface (SEI) film. Herein, Si@C/P nanoparticles with excellent electrochemical properties were prepared simply by sol-gel method and carbonization process. For lithium-ion batteries, phosphorus-doped phenol formaldehyde resin was used as carbon source for the first time, and phosphorus was successfully doped into carbon skeleton. The synergistic effect of carbon layer and phosphorus doping limits the volume expansion of silicon, and improves the diffusion rate of Li+. The Si@C/P anode exhibits a high initial Coulombic efficiency (ICE) of 84.4% and a specific capacity of 1873 mAh g−1 at 1 A g−1 after 100 cycles. The material shows a good rate performance, the average specific capacity reaches 1422.3 mAh g−1 even at a high current density of 4 A g−1, demonstrating a bright perspective.
Herein, natural fiber (energy reeds and rice straw) reinforced with phenol formaldehyde (PF) polymeric resin biocomposites are developed and reported in this study. The dimensions of energy reeds and ...rice straws used for this research were 0.5–1.66 mm and 0.1–3.55 mm, respectively. The hot-pressing technology was used for manufacturing the biocomposites. The proportions for mixing of rice straw/energy reed fibers in composite systems were 90/0, 54/36, 36/54, and 0/90 whereas remaining 10% were belong to PF resin. The nominal densities of the biocomposite panels were 680 kg/m
3
, however the actual densities were 713.655, 725, 742.79, and 764.49 kg/m
3
. The main objective of this study is to develop hybrid biocomposites from different proportions of energy reeds and rice straw fibers using PF resin and to find the convenient ratio and materials for biocomposites production. The obtained results demonstrate that mechanical properties and stability against the moisture increases with the increase of energy reeds loading in the composite systems. The biocomposite developed from 100% energy reeds provided the higher mechanical properties compared to 100% rice straw. The thermal and morphological properties of the produced biocomposite materials were investigated and found significant. The thermo-mechanical properties of the composite materials increase with the increase in energy reed fiber loading in composite system. Furthermore, the coefficient of variation (R
2
) also demonstrates a positive attributions of energy reed fibers loading in composite systems. Moreover, the overall performances of the developed biocomposite panels demonstrate them as potential and novel candidate to the composite community in the coming times.
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