Multifunctional Modifier Research Articles

Green Recycling of Carbon/Carbon Composites by Solid-State Shear Milling Technology as a Polyamide Multi-Functional Modifier

Carbon/carbon (C/C) composite materials are widely used in aerospace, the military and nuclear energy. The outstanding mechanical qualities of C/C composites mean that they are difficult to crush and recycle using traditional technology. The current recycling methods primarily involve stacking and landfill disposal. Therefore, achieving efficient and environmentally friendly recycling of carbon/carbon (C/C) composites is an urgent and challenging issue. In this work, we reported a simple high-value recycling approach for carbon–carbon frictional composite material (CFCM). The solid-state shear milling (S3M) technology is employed to achieve ultrafine milling of carbon matrices in carbon/carbon (C/C) composite materials while preserving carbon fibers. By this means, carbon fibers and the carbon matrix were mainly split, and the prepared composite powder had combined functionalities of conductivity, thermal conductivity, reinforcement, and wear resistance. The experimental results showed that the tensile strength of the material increased from 64.35 MPa to 72.79 MPa after being compounded with PA6, and the thermal conductivity increased from 0.211 W/mK to 0.611 W/mK. The friction coefficient was reduced from 0.51 to 0.36, a reduction of 25.4%, and the heat deflection temperature was increased from 47.2 °C to 108.2 °C. The S3M technique proposed in this work is an efficient, high-value, and scalable recycling strategy for CFCM, which can be used to produce value-added products and has great application prospects.

Conductivity and Breakdown Properties of Epoxy Resin for HVDC Bushing by Multifunctional Modifier

Conductivity and Breakdown Properties of Epoxy Resin for HVDC Bushing by Multifunctional Modifier

Lead fluoride as a multifunctional modifier in bismuth gadolinium borate glasses: Optical, structural, and radiation attenuation characterization

This study systematically evaluates the role of PbF2 in altering the optical and radiation shielding properties of bismuth gadolinium borate glasses with compositions 30Bi2O3–Gd2O3-xPbF2-(70-x)B2O3, for x ranging from 0 to 40 mol. %. The introduction of PbF2 significantly modified the absorbance profile, exhibiting distinct absorption peaks at 3.45, 4.15, and 4.69 eV, shifting from a flat curve in the undoped sample to well-defined peaks with increasing PbF2 content. Crucially, a reduction in both the direct and indirect optical band gaps was observed as the PbF2 content increased, indicating changes in the electronic structure of the glasses. Photon and neutron shielding capabilities were analyzed, revealing that the linear attenuation coefficient (μ), half-value layer (T0.5), and effective atomic number (Zeff) were enhanced with PbF2 additions. Notably, the BGPB5 sample contained 40 mol. % PbF2 outperformed other compositions, offering the highest attenuation efficiency, which surpassed some conventional glasses and concretes. Simultaneously, an inversely proportional relationship was found between PbF2 concentration and the effective removal cross-section for fast neutrons (ΣR), demonstrating the BGPB1 sample's superiority as a neutron shield. The incorporation of PbF2 in the glass matrix not only improved gamma radiation shielding but also tuned the optical properties, marking these glasses as potential candidates for multifunctional radiation shielding applications.

Preparation of multifunctional chitosan derivative containing 10-undecenoyl and galloyl groups and its application in styrene-butadiene rubber/silica composites

The traditional small molecular rubber antioxidants have the shortcomings of single function, toxicity, and heavy dependence on non-renewable fossil resources, which limits their green, high-efficiency, and sustainable development in the rubber industry. To address this problem, in this work, we first developed a chitosan derivative containing 10-undecenoyl groups (COS-UC) and then combined it with the natural small molecular antioxidant gallic acid (GA) to prepare chitosan derivative containing 10-undecenoyl and galloyl groups (COS-UC-GA). The obtained COS-UC-GA was used as multifunctional modifier and applied in styrene-butadiene rubber (SBR)/silica composites. The effects of COS-UC-GA on the curing characteristics, crosslinking density, morphology, mechanical properties, and interfacial interaction of SBR/silica composites were explored in detail. The results indicated that the COS-UC-GA can effectively accelerate the vulcanization process of SBR/silica compounds, promote the uniform dispersion of silica, improve the mechanical properties of SBR/silica composites, and significantly enhance the interfacial interaction between the silica and rubber. This research provides a new perspective for developing green and eco-friendly multifunctional modifiers, which not only contributes to the comprehensive utilization of biomass resources, but also can promote the green development of the rubber industry.

Preparation and Application of a Multifunctional Interfacial Modifier for Ramie Fiber/Epoxy Resin Composites.

A multi-functional modifier, which could improve the mechanical and thermal performance simultaneously, is significant in composites production. Herein, inspired by the chemistry of mussel, an interfacial modifier named FPD was designed and synthesized through one simple step, which was attached by three functional groups (including catechol, N-H bond, and DOPO). Due to the innate properties of each functional group, FPD played multiple roles: adhere to the ramie fibers from catechol and cure with the epoxy resin from -NH-, an antiflaming property from DOPO, and the compatibilizer between ramie fibers and epoxy resin was also improved by changing the polarity of ramie fiber. All of the above functions can be proved by means of water contact angle (WCA), atomic force microscope (AFM), and scanning electron microscopy (SEM), etc. After solidification, the ramie fiber/epoxy composites demonstrated superior performances in terms of good mechanical properties and excellent flame retardant property. With the addition of 30 wt.% FPD, the tensile strength and modulus of the ramie/epoxy composite showed an improvement of 37.1% and 60.9%, and flexural strength and modulus of the composite were improved by 8.9% and 19.3% comparing with no addition composite. Moreover, the composite could achieve the goal for V-0 rating in the UL-94 test and LOI value was 34.6% when the addition of FPD reached 30 wt.%. This work provided us with an efficient method for fabricating nature fiber/epoxy composites with good properties.

Metalloporphyrin conjugated porous polymer in-situ grown on a Celgard separator as multifunctional polysulfide barrier and catalyst for high-performance Li-S batteries

The severe shuttling of soluble polysulfides (LiPSs) (Li2Sx, 4 ≤ x ≤ 8) and sluggish kinetics of solid–solid conversion (Li2S2 → Li2S), lead to the premature end of discharge, resulting in fast capacity decay, limiting the practical performance and safety of lithium-sulfur batteries (LSBs). Functional modifiers on separators exhibit significant performances in migrating diffusion and promoting conversion for LiPSs; thus, endowing the separator with multiple high-performance parameters by multifactorial engineering to address the two issues mentioned above is an urgent need. Herein, for the first time, an ultra-light (≈0.14 mg cm−2) and multifunctional modifier consisting of metalloporphyrin conjugated porous polymer (Al-CPP) is interface-induced growth on the commercial separator to develop advanced LSBs. The electrocatalyst of metalloporphyrin is covalently constructed by an imidazolium-containing linker with bis(trifluoromethane)sulfonimide (TFSI−) anions within the porous skeleton, improving diffusion and conversion of LiPSs as well as facilitating electrolyte accessibility and Li+ transport, thereby performing enhanced full-range sulfur redox kinetics, and guiding uniform Li deposition. The in-situ growth of metalloporphyrin conjugated porous polymer is further verified in LSBs that realize superior rate performances and long lifespans. This contribution proposes an efficient in-situ growth of an ultra-light modifier design strategy to functionalize separators and inspires multi-function synergetic integration facing high-performance LSBs.

Designing Strong, Tough, Fluorescent, and UV-Shielding PLA Materials by Incorporating a Phenolic Compound-Based Multifunctional Modifier.

The realization of high stiffness, high extensibility, and multi-functions for polylactic acid (PLA) is a vital issue for its practical applications. Herein, hydroxyalkylated tannin acid (mTA), a phenolic compound-based modifier with plentiful flat aromatic structures and flexible isopropanol oligomers, is designed and fabricated to act as the multifunctional modifier for PLA. The mTA exhibits the capability of emitting fluorescence and blocking UV light due to the combination of flat aromatic structures and plentiful flexible chains. Besides, mTA with high grafting degree (h-mTA) shows an excellent compatibility to PLA due to the hydrogen bonding interface and the high affinity of grafted isopropanol oligomers to PLA. As a result, the as-prepared PLA/h-mTA20 composite exhibits a strikingly improved extensibility by 61.2 times while maintaining the high yield strength of PLA. Moreover, PLA/h-mTA can serve as a fluorescent material with multi-mode responsiveness as well as a UV-shielding material with high transparency. We envision that this work opens a novel yet facile way to prepare a strong, tough, and multifunctional PLA material with expanded application scopes and will promote the practical applications of phenolic compounds in polymers.

Crosslinked thioctic acid as a multifunctional buried interface modifier for high-performance inorganic perovskite solar cells

By using crosslinkable small molecule thioctic acid (TA) as a multifunctional modifier to insert into the ZnO/perovskite buried interface, a champion efficiency of 16.56% was achieved for the CsPbI2Br PSCs with significantly improved device stability.

Multifunctional modifier for regulating the properties of concrete mixtures

The purpose of this work is the synthesis of new highmolecular surfactants polyalkylacrylates and the establishment of correlations between their colloidal chemical properties. Well-known methods for the synthesis and determination of the properties of surfactants were used. New high molecular surface-active substances (HMSAS) were obtained based on the reaction of polymer-analogous transformations. The resulting copolymers contain side hydrocarbon radicals of various lengths. Polyalkylacrylates were obtained by esterification with aliphatic alcohols (butyl, octyl, decyl) in a mixture of organic solvents and the presence of a catalyst, sulfuric acid. The surface activity and foaming ability of the obtained new HMSAS in aqueous solutions have been studied. The results obtained showed that with an increase in the length of the aliphatic hydrocarbon radical in the chain of macromolecules, the surface activity of polyalkylacrylates increases. An analysis of the results showed a good correlation between foaming and surface activity of the investigated HMSAS. Based on research, it was found that the stability of the foams is largely determined by the interaction of the HMSAS molecules in the monolayer.

Modulating Residual Lead Iodide via Functionalized Buried Interface for Efficient and Stable Perovskite Solar Cells

Sufficient lead iodide (PbI2) in perovskite films effectively passivates defects and enhances device performance. However, excess large-grained PbI2 clusters tend to be randomly distributed in the perovskite layer, which mitigate the positive effect of the PbI2. Here, we first modulated the distribution and size of PbI2 clusters by functionalizing the buried interface of 4,4′-diaminodiphenyl sulfone hydroiodide (DDSI2). As a multifunctional modifier, DDSI2 can optimize the energy level of tin oxide (SnO2) and passivate the buried interface defects via −NH3+ and S═O functional groups. Moreover, the hydrogen bonding and coordination between DDSI2 and perovskite retard the crystal growth rate and alleviate the lattice stress, thereby improving the quality of the perovskite and modulating the distribution of PbI2. Consequently, the DDSI2-modified device displays a power conversion efficiency of 24.10% and a storage stability of 1800 h. We demonstrate a unique strategy for the rational control of PbI2 for efficient and stable perovskite solar cells.

A new triphenylphosphonium-conjugated amphipathic cationic peptide with improved cell-penetrating and ROS-targeting properties

We study for the first time whether triphenylphosphonium (TPP) moiety can improve cellular delivery and redox properties of amphipathic cationic peptides based on YRFK/YrFK cell-penetrating and cytoprotective motif. TPP moiety was found to increase reducing activity of both stereoisomeric peptides in solution and on electrode surface in association with TPP-mediated intramolecular interactions. Among TPP-conjugated peptides, newly synthesized TPP3-YrFK featured both increased antioxidant efficacy and proteolytic resistance. TPP-conjugated peptides preferably mitigated endogenic ROS in mitochondria and cytoplasm of model glioblastoma cells with increased oxidative status. This anti-ROS effect was accompanied by mild reversible decrease of reduced glutathione level in the cells with relatively weak change in glutathione redox forms ratio. Such low interference with cell redox status is in accordance with non-cytotoxic nature of the compounds. Intracellular concentrations of label-free peptides were analyzed by LC–MS/MS, which showed substantial TPP-promoted penetration of YrFK motif across cell plasma membrane. However, according to ΔΨm analysis, TPP moiety did not profoundly enhance peptide interaction with mitochondrial inner membrane. Our study clarifies the role of TPP moiety in cellular delivery of amphipathic cationic oligopeptides. The results suggest TPP moiety as a multi-functional modifier for the oligopeptides which is capable of improving cellular pharmacokinetics and antioxidant activity as well as targeting increased ROS levels. The results encourage further investigation of TPP3-YrFK as a peptide antioxidant with multiple benefits.

Amidine thiourea as a multifunctional modifier of buried interface for effective perovskite solar cells with reduced lead leakage

The defects at buried SnO 2 /perovskite interface can influence the performances of perovskite solar cells by causing the poor perovskite crystallinity, bad interface connection, undesired interfacial recombination and electron transfer efficiency. Now, multifunctional amidine thiourea is used to modify the buried SnO 2 /perovskite interface. The amidine thiourea can passivate the interface defects by the electron donation roles of N and S atoms, improve the electron transfer efficiency by enhancing the interface connection and regulating the interface energy level matching, reduce lead leakage and reinforce the structural stability of device by the coordination and hydrogen bond interaction. The perovskite solar cells with the amidine thiourea modification exhibit an enhanced power conversion efficiency (20.48%) and stability, outperforming than that of control device (18.65%). Modifying the buried interface with small organic molecule is a feasible and efficient method to improve the performances of PSCs. The amidine thiourea interface chemical bridge can accelerate the interface charge extraction by realizing the tight connection and regulating the energy level matching of SnO 2 /perovskite interface. Besides, amidine thiourea can passivate the oxygen vacancy defects on SnO 2 and the uncoordinated Pb defects on perovskite. In addition, the strong chemical interaction between ADT and Pb can reduce the lead leakage in device. After modifying the SnO 2 /perovskite interface with amidine thiourea, the power conversion efficiency and stability of device are all improved. • Amidine thiourea (ADT) is used to modify the buried SnO 2 /perovskite interface. • ADT can passivate the buried oxygen vacancy defects and uncoordinated Pb 2+ defect. • ADT can enhance connection and regulate energy level matching at buried interface. • ADT can reduce lead leakage through strong chemical interactions. • ADT-modified devices exhibit enhanced power conversion efficiency and stability.

Preparation of multifunctional silicon‐phosphorus acrylate particles for the simultaneous improvement of the flame retardancy and mechanical performance of polylactic acid

AbstractPolylactic acid (PLA) is a biodegradable plastic that currently has limited application owing to its poor fire resistance and brittleness. Herein, a multifunctional silicon‐phosphorus acrylic resin(P/Si‐ACR) is designed to endow both flame retardancy and toughness to PLA. P/Si‐ACR is prepared by seeded emulsion polymerization with polysiloxane as the core layer and diethyl methylphosphonate acrylate and 9, 10‐dihydro‐9‐oxa‐10‐phosphophenanthrene‐10‐oxide acrylate as the shell materials. P/Si‐ACR has a particle size of approximately 200 nm and glass transition temperatures of −38 and 152°C for the core and shell layers, respectively. Addition of 7 wt% P/Si‐ACR to PLA increases the notched impact strength and elongation at break by 124% and 46%, respectively. This improved mechanical performance is due to the elasticity of silicone rubber and the promotion of crystallization by P/Si‐ACR. Combustion testing revealed that the limiting oxygen index increases from 19.1% to 22.5%, while the peak heat release rate decreases by 36%. This enhanced flame retardancy is due to the synergistic effect of phosphorus and silicon, with the former promoting graphitization and inhibiting the free radical degradation of PLA, and the latter stabilizing the char residue. Therefore, P/Si‐ACR is a promising multifunctional modifier that can achieve an optimal balance among flame retardancy, crystallization performance, and toughness in polymers.

A high-protein retained PES hemodialysis membrane with tannic acid as a multifunctional modifier

A high protein retention polyethersulfone (PES) membrane was prepared by nonsolvent-induced phase separation and surface coating, which exhibited enhanced hemocompatibility and antioxidant stress performance. The cross-linked network was constructed by tannic acid (TA) and alpha-lipoic acid (α-LA) on the surface of the membrane, which controlled the pores to a reasonable size. The enrichment of heparin-like groups on the membrane surface, implemented by “hydrophobic interaction” and “click reaction”, confers anticoagulant properties; the presence of a large number of phenolic hydroxyl groups from TA and the introduction of α-LA allows the modified membranes to intervene in oxidative stress. The hemocompatibility characterizations included plasma recalcification time (PRT), activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and hemolysis rate (HR). Additionally, the DPPH ABTS radical scavenging capacity was tested to evaluate the antioxidant performance. The results show that the modified membrane presents an outstanding protein retention rate (99.3%) along with permeability. In addition, the PRT is prolonged to 341.7 s, and the DPPH• scavenging ability reaches 0.74 µmol•cm-2. The membranes can be easily prepared and present excellent comprehensive performance. This work provides a simple and facile strategy for the fabrication of hemodialysis membranes with controllable pore sizes.

Wood-Inspired Filter with a Lignin-Reinforced Nanocomposite Layer for Enhanced Oil/Water Separation and Selective Dye Removal

Nanocomposite filter membranes have attracted a great deal of attention in water purification. However, the weak interaction between nanomaterials and filter matrices severely reduces the stability and causes secondary pollution. Herein, inspired by the structure and function of natural wood, we report a simple strategy for fabricating a filter that uses alkaline lignin as a multifunctional modifier to tailor graphene oxide (GO) and bridge from GO to the surface of the glass fiber (GF). The obtained lignin-GO-modified GF filter was covered by a thin nanocomposite layer (∼2 μm) and exhibited hydrophilic and underwater oleophobic properties. It performed well in separating different oil-in-water emulsions (>92% for n-hexadecane, n-dodecane, and engine oil) under gravity and in selectively removing cationic dyes due to interception and adsorption via electrostatic effects and π–π interactions. Moreover, the filter had good stability and could be regenerated by washing without a significant loss of removal efficiency of n-dodecane-in-water emulsions during five consecutive cycles (1.86% per cycle). Therefore, this study shows that the wood-inspired filter membrane holds considerable promise for wastewater treatment, especially for oil/water separation and selective dye removal.

Hybrid Ce-Fe2O3/ZIF-67 Photoanode with Efficient Photoelectrochemical Water Oxidation Performance.

Surface states and slow water oxidation kinetics greatly limit the photoelectrochemical (PEC) water oxidation performance of Fe2O3. To solve the above problems, coupling Fe2O3 with a passivation layer and an oxygen evolution cocatalyst, respectively, is the common method. Though this method may improve its PEC performance, this also results in a low charge-transfer efficiency caused by the interface resistance between Fe2O3 and the modification materials (passivation layer and oxygen evolution cocatalyst). Therefore, it is important to identify a multifunctional modifier material to reduce the interfacial resistance due to the presence of multiple different materials. In this work, we introduced a thin cobalt-based metal-organic framework layer (ZIF-67) as a dual-functional material that acted as both a passivation layer and a water oxidation cocatalyst for a photoanode based on Ce-Fe2O3 nanorod arrays. The ZIF-67 layer inhibited charge carrier recombination by passivating the surface states. The PEC performance was improved due to the rich Co2+ photogenerated hole-capture sites, which facilitated charge transfer and separation. As expected, the Ce-Fe2O3/ZIF-67 photoanode exhibited superior water oxidation performance, with a photocurrent of 2.07 mA cm-2 at 1.23 VRHE, which is 1.74 times higher than that of the Ce-Fe2O3 photoanode. The onset potential was negatively shifted by 71 mV. This study provides basic insights and a strategy for reducing interfacial resistance in hybrid materials.

Superior flame retardancy, antidripping, and thermomechanical properties of polyamide nanocomposites with graphene‐based hybrid flame retardant

AbstractGraphene is considered one of the most prominent halogen‐free multifunctional flame retardants for polymers, and the resultant nanocomposites also display a good balance of properties. However, the biggest concern nowadays is thermal oxidative degradation, which mainly affects the flame retardant (FR) efficiency of graphene. To improve the flame retardancy and thermal oxidative degradation efficiency, graphene was functionalized with a combination of polycyclotriphosphazes and siloxanes via a sol–gel surface modification method, yielding a graphene‐based hybrid FR (PSGO) containing multiple elements (P, N, S, and Si). The PSGO‐containing PA6 composite exhibited significant improvements in the water resistance, thermal, mechanical, and FR properties, as compared with those of 3‐isocyanatopropyltriethoxysilane functionalized graphene oxide (ITS‐GO) and siloxane‐modified polycyclotriphosphazenes (m‐PZS) individually. The peak heat release rate and total heat release values of the PA6 composites with 10 wt% PSGO decreased by 45.7% and 36.9%, respectively, compared to those of pristine PA6. Moreover, it was confirmed that 10 wt% PSGO in the PA6 composite resulting in a V–0 rating in the UL‐94 tests, even after the water immersion test. These attractive properties are attributed to the resistance to thermal‐oxidative degradation of PSGO and the improved interfacial interactions with the polymer matrix. Therefore, this PSGO can be used as a multifunctional modifier to improve the water resistance, thermal, mechanical, and FR properties of polymers.

Potassium nitrilotriacetate as a multifunctional modifier of the buried interface for hysteresis-reduced perovskite solar cells.

Potassium nitrilotriacetate (NTAK) was employed to modify the buried SnO2/perovskite interface. Benefiting from the coordination roles of carboxyl and amino groups, and the diffusion role of potassium ions, NTAK could enhance the bilateral connection, improve perovskite morphology, suppress non-radiation recombination, and reduce the hysteresis effect. The optimal device with NTAK modification achieved an effective power conversion efficiency of 21.02%. This was a successful attempt to improve the buried interface.

A thiourea resin polymer as a multifunctional modifier of the buried interface for efficient perovskite solar cells with reduced lead leakage

Thiourea resin can improve the connection performances and energy level matching of the buried SnO2/perovskite interface and suppress lead leakage through strong interactions.

A phosphorus-containing imidazole derivative towards the liquid oxygen compatibility and toughness of epoxy resin.

In order to develop a liquid oxygen-compatible (LOX-compatible) matrix resins for polymer-based fiber-reinforced composites, a novel phosphorus-containing imidazole derivative called VAD containing multifunctional groups was synthesized and used as a co-curing agent for epoxy resin (EP) with simultaneous LOX-compatibility and mechanical improvement. A phosphorus group was introduced into the EP to capture the free radicals generated during the pyrolysis of the polymer to improve LOX compatibility, and the trimethylene group was introduced as a flexible spacer to enhance the toughness of the cured material. In comparison to pure EP, the modified EP with only 2.5 wt% VAD showed excellent mechanical properties with 23.0% and 75.6% increase in tensile and impact strength, respectively. Furthermore, as the content of VAD increased, a thermoset compatible with LOX (according to the liquid oxygen impact test) was obtained, and the flame retardancy was improved (according to the limiting oxygen index test). However, there was no significant sacrifice of transparency or thermal stability. In addition, the LOX compatibility mechanism was analyzed using X-ray photoelectron spectroscopy. As an efficient multi-functional modifier, VAD has a bright future in the modification realm of EP materials.