Highly efficient catalytic Fenton-Like reactions of bimetallic Fe/Cu chelated on radiation functionalized nonwoven fabric for pollutant control.

A remarkably efficient and affordable Fe/Cu bimetallic catalyst featuring a substantial light energy utilization and compatibility with a sizable substrate was developed for Fenton-like reactions aimed at pollutant control. Specifically, a novel strategy was employed to synthesize high-density metal sites (Fe:Cu ≈ 3:1) robustly embedded on polyethylene/polyethylene terephthalate nonwoven fabric (PE/PET NWF) via radiation-induced graft polymerization (RIGP) and subsequent chemical modification, labeled as Fe/Cu-PPAO. Its high effectiveness was demonstrated by degrading 50 mg/L of tetracycline hydrochloride within 30 min in the presence of H2O2 under simulate sunlight irradiation. It was investigated that amidoxime groups regulated the optical gaps and HOMO-LUMO gaps of metal ions to enable the absorption of a broader spectrum light while the Cu2+ facilitated the transfer of electrons between the bimetal ions to achieve an improved reaction path. Furthermore, X-ray absorption fine structure (XAFS) and density functional theory (DFT) calculations further revealed its special complex state and delicate electronic structure between bimetal ions and amidoxime groups. Our study offers a new strategy to synthesize high-density bimetallic sites catalyst for environmental remediation and pushes forward insight into understanding the catalytic mechanism of bimetallic Fenton-like catalysts.

Metal-Organic Framework@Metal Oxide Heterostructures Induced by Electron-Beam Radiation.

Metal organic frameworks (MOFs) are a distinct family of crystalline porous materials finding extensive applications. Their synthesis often requires elevated temperature and relatively long reaction time. We report here the first case of MOF synthesis activated by high-energy (1.5 MeV) electron beam radiation from a commercially available electron-accelerator. Using ZIF-8 as a representative for demonstration, this type of synthesis can be accomplished under ambient conditions within minutes, leading to energy consumption about two orders of magnitude lower than that of the solvothermal condition. Interestingly, by controlling the absorbed dose in the synthesis, the electron beam not only activates the formation reaction of ZIF-8, but also partially etches the material during the synthesis affording a hierarchical pore architecture and highly crystalline ZnO nanoparticles on the surface of ZIF-8. This gives rise to a new strategy to obtain MOF@metal oxide heterostructures, finding utilities in photocatalytic degradation of organic dyes.

Radiation-Induced In Situ-Printed Nonconjugated Fluorescent Nonwoven Fabric with Superior Fluorescent Properties.

A new technique is proposed for the in situ printing of fluorescent fabrics with superior fluorescent properties that have the potential for continuous roll-to-roll production in the industry. Nonconjugated chemical moieties were covalently connected to polyethylene/polypropylene nonwoven fabric (PE/PP NWF) to successfully prepare fluorescent PE/PP NWF, which emits a bright blue light and has a high quantum yield (∼83.35%) that can be attributed to a unique aggregation-induced emission effect. The fluorescent PE/PP NWF exhibits excellent fluorescent stability under high shear forces during accelerated laundering and in harsh chemical environments. The fluorescent PE/PP NWF can also be tailored into diverse shapes and printed in situ with high resolution. The versatility of the method was also demonstrated by fabricating fluorescent materials with different polymer matrices such as Nylon 66 fiber and PE terephthalate membrane.

Fabrication and Potential Applications of Highly Durable Superhydrophobic Polyethylene Terephthalate Fabrics Produced by In-Situ Zinc Oxide (ZnO) Nanowires Deposition and Polydimethylsiloxane (PDMS) Packaging.

Considerable attention has been devoted to the in-situ deposition of zinc oxide (ZnO) nanowires (ZnO-NWs) on the surface of organic supports, due to their very wide applications in superhydrophobicity, UV shielding, and nanogenerators. However, the poor interfacial bond strength between ZnO-NWs and its support limits their applications. Herein, we developed a facile process to grow robust ZnO-NWs on a polyethylene terephthalate (PET) fabric surface through simultaneous radiation-induced graft polymerization, hydrothermal processing, and in-situ nano-packaging; the obtained materials were denoted as PDMS@ZnO-NWs@PET. The introduction of an adhesion and stress relief layer greatly improved the attachment of the ZnO-NWs to the support, especially when the material was subjected to extreme environment conditions of external friction forces, strong acidic or alkaline solutions, UV-irradiation and even washing with detergent for a long time. The PDMS@ZnO-NWs@PET material exhibited excellent UV resistance, superhydrophobicity, and durability. The ZnO-NWs retained on the fabric surface even after 30 cycles of accelerated washing. Therefore, this process can be widely applied as a universal approach to overcome the challenges associated with growing inorganic nanowires on polymeric support surfaces.

Electron Beam Irradiation as a General Approach for the Rapid Synthesis of Covalent Organic Frameworks under Ambient Conditions.

Crystalline porous materials such as covalent organic frameworks (COFs) are advanced materials to tackle challenges of catalysis and separation in industrial processes. Their synthetic routes often require elevated temperatures, closed systems with high pressure, and long reaction times, hampering their industrial applications. Here we use a traditionally unperceived strategy to assemble highly crystalline COFs by electron beam irradiation with controlled received dosage, contrasting sharply with the previous observation that radiation damages the crystallinity of solids. Such synthesis by electron beam irradiation can be achieved under ambient conditions within minutes, and the process is amendable for large-scale production. The intense and targeted energy input to the reactants leads to new reaction pathways that favor COF formation in nearly quantitative yield. This strategy is applicable not only to known COFs but also to new series of flexible COFs that are difficult to obtain using traditional methods.

Fabrication of new conductive surface-metallized UHMWPE fabric with improved thermal resistance.

A new UHMWPE-based conductive fabric was successfully prepared by radiation-induced graft polymerization and subsequent post-modification, followed by electroless deposition. The chemical structure and composition of modified UHMWPE fabrics were investigated in detail by ATR-FTIR, 29Si NMR, and XPS to confirm grafting and post-modification. After electroless deposition, the morphology, thermal stability, and crystal structure of original and modified fabrics were characterized by SEM, TG, DSC and XRD. Cu-deposited UHMWPE fabric exhibited much better thermal resistance than that of UHMWPE and Cu@UHMWPE-g-PAAc. In order to improve the oxidation resistance of copper-deposited fabric, nickel was processed on copper-coated UHMWPE fabric to protect the copper layer. An electromagnetic shielding effect test showed the nickel-copper coated UHMWPE fabric could shield 94.5% of the electromagnetic wave in the frequency range of 8-12 GHz. This work provides an approach for addressing the issue of poor thermal resistance of metal-coated polymeric materials due to the inherent low melting point of the organic support.

In-situ formation of durable akaganeite (ß-FeOOH) nanorods on sulfonate-modified poly(ethylene terephthalate) fabric for dual-functional wastewater treatment.

Industrial oily wastewater with dye-pollution is a critical environmental issue for water purification. However, the fabrication of effective and stable materials for oil-water separation and simultaneous degradation of organic contaminants remains a critical challenge. Herein, we report a new process for in-situ formation of akaganeite (ß-FeOOH) nanorods layer on the surface of poly(ethylene terephthalate) (PET) fabric via radiation-induced graft polymerization of glycidyl methacrylate, which is then sulfonated and mineralized. The resultant product is labeled as ß-FeOOH@PET, which exhibits dual purification by demonstrating an effective oil-water separation and organic dyes photodegradation under the illumination of visible light. It provides stable performance even after 1000 wash cycles. The sulfonated layer acts as not only an electronic transport layer to prevent electron-hole recombination, but also as an anchored interface for immobilizing ß-FeOOH nanorods on the sulfonated layer via strong covalent bonds. Overall, the superhydrophilicity and underwater superoleophobicity of ß-FeOOH@PET fabric, along with its robustness with a flexible organic substrate and its dual purification function, provide a new insight toward oily wastewater remediation and water purification in large-scale applications.

Co2+ anchored on surface-functionalized PET non-woven fabric and used as high efficiency monoatom-like catalyst for activating Oxone in water.

Fenton-like processes have emerged as most promising techniques for generating reactive oxygen-containing radicals to deal with increasing levels of environmental pollution. Developing novel catalysts with simple manufacturing requirements, excellent activity levels, and stability remains a long-term goal in terms of practical application. So herein, a new polyethylene terephthalate (PET) non-woven fabric based composite catalyst has been fabricated, using radiation-induced graft polymerization of a functionalized group to chelate Co2+ ions as heterogeneous catalysts in peroxymonosulfate (Oxone) activation. Several impact factors, including catalyst dosage, Oxone concentration, reaction temperature, pH value, Co2+ precipitation ratio (of Co@PET at different pH values), and highly concentrated NaCl have been investigated here. Notably, Co@PET has shown the lowest activation energy of any reported catalyst, for degrading RhB by activating Oxone. Interestingly, as experimental RhB and Oxone solutions were passed through single Co@PET sheets, the RhB was decomposed into a colorless solution in the penetration process. Based on radical trapping and quenching experiments, a channel was determined to dominate RhB degradation, and furthermore, Co@PET could be re-used for RhB degradation by activating Oxone. These results showed that Co@PET effectively provided improved Fenton-like catalytic performance and stability, and was suitable for practical applications.

Flexible and Thermally Induced Switchable Fire Alarm Fabric Based On Layer-by-Layer Self-Assembled Silver Sheet/Fe3O4 Nanowire Composite.

Textiles with fire detection will appeal for the interior decoration of houses and play a critical role in public security. Herein, we fabricated a sandwichlike fire alarm fabric (Ag@Fe3O4-MS) based on Fe3O4 nanowire (NW) arrays and fish-scale-like silver sheets, designed by in situ layer-by-layer assembly on the surface of polypropylene (PP) nonwoven fabric. The Ag@Fe3O4-MS sensor has fish-scale-like silver sheets as self-assembling electrode layers on the upper and lower sides of fabric, which can be tailored into various shapes and integrated into other flexible electronics. The sensor provides a real-time monitoring strategy for early warning fire detection (below 100 °C). At room temperature, the fabricated Ag@Fe3O4-MS sensor is electrically insulating, while it switches to an electrical conductor when exposed to flame. In view of its fast response time (2 s) and sustained working time (at least 15 min), the sensor with a connected alarm light can immediately alert people of house fires. More importantly, this sensor can provide additional real-time information on the fire location and reliable real-time monitoring of fire rekindling. The sensor was exposed to fire for successive cycles with an average response of I = 43 mA, confirming the reliable repeatability to detect fires. This ultralight, flexible Ag@Fe3O4-MS sensor could have broad applications in home safety. Moreover, the sandwichlike design provides a reliable strategy to modify household fabric items to provide a fire warning function.

Flexible and Highly Sensitive Humidity Sensor Based on Sandwich-Like Ag/Fe3O4 Nanowires Composite for Multiple Dynamic Monitoring.

Functional textiles with unique functions, including free cutting, embroidery and changeable shape, will be attractive for smart wear of human beings. Herein, we fabricated a sandwich-like humidity sensor made from silver coated one-dimensional magnetite nanowire (Fe3O4 NW) arrays which were in situ grown on the surface of modified polypropylene nonwoven fabric via simultaneous radiation induced graft polymerization and co-precipitation. The humidity sensor exhibits an obvious response to the relative humidity (RH) ranging from RH 11% to RH 95% and its response value reaches a maximum of 6600% (ΔI/I0) at 95% relative humidity (RH). The humidity sensor can be tailored into various shapes and embroidered on its surface without affecting its functionalities. More interesting, the intensity of its response is proportional to the size of the material. These features permit the sensor to be integrated into commercial textiles or a gas mask to accurately monitor a variety of important human activities including respiration, blowing, speaking and perspiration. Moreover, it also can distinguish different human physical conditions by recognizing respiration response patterns. The sandwich-like sensor can be readily integrated with textiles to fabricate promising smart electronics for human healthcare.

In-situ mineralized robust polysiloxane-Ag@ZnO on cotton for enhanced photocatalytic and antibacterial activities.

A bifunctional interfacial layer was introduced onto the surface of cotton fabric which not only enhanced the interfacial bonding between Ag@ZnO and organic substrates but also improved the photocatalytic performance simultaneously. In detail, a modified cotton fabric (denoted as Cot-g-Si/Ag@ZnO) was fabricated through radiation-induced graft polymerization of γ-methacryloxypropyl trimethoxysilane and followed the in-situ formation of ZnO and loading of Ag nanoparticles simultaneously. Owing to ZnOSi between the graft chains and Ag@ZnO photocatalyst, the charge carrier concentration increased and Ag was prevented from oxidizing through the partial separation from ZnO, leading to enhanced near-field amplitudes of the localized surface plasmon resonance. Cot-g-Si/Ag@ZnO also exhibited excellent photocorrosion resistance, photostability and laundering durability. Its photocatalytic activity was fully maintained after several photodegradation cycles; moreover, after laundering durability test, the photocatalytic activity was improved compared with the newly prepared one. Credible mechanism for the photocatalytic activity of Cot-g-Si/Ag@ZnO under sunlight irradiation is proposed.

Improving the Supercritical CO2 Foaming of Polypropylene by the Addition of Fluoroelastomer as a Nucleation Agent.

In this study, a small amount of fluoroelastomer (FKM) was used as a nucleating agent to prepare well-defined microporous PP foam by supercritical CO2. It was observed that solid FKM was present as the nanoscale independent phase in PP matrix and the FKM could induce a mass of CO2 aggregation, which significantly enhanced the diffusion rate of CO2 in PP. The resultant PP/FKM foams exhibited much smaller cell size (~24 µm), and more than 16 times cell density (3.2 × 108 cells/cm³) as well as a much more uniform cell size distribution. PP/FKM foams possessed major concurrent enhancement in their tensile stress and compressive stress compared to neat PP foam. We believe that the added FKM played a key role in enhancing the heterogeneous nucleation, combined with the change of local strain in the multiple-phase system, which was responsible for the considerably improved cell morphology of PP foaming. This work provides a deep understanding of the scCO2 foaming behavior of PP in the presence of FKM.

Fabrication of highly durable polysiloxane-zinc oxide (ZnO) coated polyethylene terephthalate (PET) fabric with improved ultraviolet resistance, hydrophobicity, and thermal resistance.

Developing a universal strategy to improve the properties of polyethylene terephthalate (PET) fibers, such as UV resistance, hydrophobicity, and thermal resistance, is highly desirable in expanding the application of PET fibers. Herein, a highly durable and robust ZnO layer was deposited onto PET fabric via radiation-induced graft polymerization (RIGP) of γ-methacryloxypropyl trimethoxysilane (MAPS) and the subsequent sol-gel in situ mineralization with zinc acetate to produce wurtzite nanocrystalline ZnO. The as-obtained material, denoted as PET-g-PMAPS/ZnO. The interfacial layer consisted of Zn-O-Si and Si-O-Si covalent bonds not only leads to an improvement in adhesion between ZnO nanoparticles and its support, but it also overcomes the poor film-forming ability of inorganic particles. Most importantly, photocatalytic self-degradation of its organic support caused by the high photocatalytic activity of ZnO can be eliminated because of high bond energy of the organic-inorganic hybrid structure. PET-g-PMAPS/ZnO exhibited excellent thermal resistance, UV resistance and durability. Superhydrophobicity was achieved by simply annealing the PET-g-PMAPS/ZnO fabric at 200 °C in ambient air, and the coated fabric still retains its superhydrophobicity after 40 laundering cycles test and even stored for a few weeks. This study presents an effective method to overcome the bottle-necks in growing inorganic nanocrystals on polymeric supports surface.

Controlling crystal polymorphism of isotactic poly(1-butene) by incorporating long chain branches.

Isotactic poly(1-butene) (iPB-1) is a high performance plastic with outstanding properties, such as flexibility, superior creep, environmental stress cracking and abrasive resistance. However, it exhibits a complex crystal polymorphism and polymorphic transformation behavior, which has limited its commercial development. In this paper, the incorporation of long chain branches (LCBs) causes coil contraction in the melt, which favors the direct melt-crystallization of form III that was generally crystallized from solutions and made of unconventional highly twined lamellae. Consequently, low-to-moderately branched iPB-1 samples as-crystallize from the melt into mixtures of form II and form III by compression-molding and fast cooling of the melt to room temperature, and the fraction of crystals of form III (fIII) increases with increasing concentration of LCBs, whereas highly branched samples can as-crystallize into pure form III with uniform crystal size distribution. The corresponding thermomechanical properties can be modified by controlling fIII.

Phosphate-Based Ultrahigh Molecular Weight Polyethylene Fibers for Efficient Removal of Uranium from Carbonate Solution Containing Fluoride Ions.

This work provides a cost-effective approach for preparing functional polymeric fibers used for removing uranium (U(VI)) from carbonate solution containing NaF. Phosphate-based ultrahigh molecular weight polyethylene (UHMWPE-g-PO4) fibers were developed by grafting of glycidyl methacrylate, and ring-opening reaction using phosphoric acid. Uranium (U(VI)) adsorption capacity of UHMWPE-g-PO4 fibers was dependent on the density of phosphate groups (DPO, mmol∙g−1). UHMWPE-g-PO4 fibers with a DPO of 2.01 mmol∙g−1 removed 99.5% of U(VI) from a Na2CO3 solution without the presence of NaF. In addition, when NaF concentration was 3 g∙L−1, 150 times larger than that of U(VI), the U(VI) removal ratio was still able to reach 92%. The adsorption process was proved to follow pseudo-second-order kinetics and Langmuir isotherm model. The experimental maximum U(VI) adsorption capacity (Qmax) of UHMWPE-g-PO4 fibers reached 110.7 mg∙g−1, which is close to the calculated Qmax (117.1 mg∙g−1) by Langmuir equation. Compared to F−, Cl−, NO3−, and SO4²− did not influence U(VI) removal ratio, but, H2PO4− and CO3²− significantly reduced U(VI) removal ratio in the order of F− > H2PO4− > CO3²−. Cyclic U(VI) sorption-desorption tests suggested that UHMWPE-g-PO4 fibers were reusable. These results support that UHMWPE-g-PO4 fibers can efficiently remove U(VI) from carbonate solutions containing NaF.

An efficient and reusable quaternary ammonium fabric adsorbent prepared by radiation grafting for removal of Cr(VI) from wastewater.

A novel quaternary ammonium polyethylene nonwoven fabric for removing chromium ions from water was prepared via radiation-induced grafting of glycidyl methacrylate and further modification with N,N'-dimethylethylenediamine. The structural and morphological characteristics of the adsorbent were analyzed using Fourier transform infrared spectroscopy (FTIR), thermogravimetry and differential thermogravimetry (TG/DTG), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The influences of several principal factors, including pH value, initial Cr(VI) concentration, contact time, and coexisting anions (including SO42-, CO32-, NO3-, PO43-, and Cl-), on adsorption performance were investigated via batch tests. The results showed that the optimum removal efficiency was 99.2% at pH 3 and the maximum adsorption quantity for Cr(VI) at 25 °C was 336 mg/g. The adsorption kinetic parameters were better fitted with the pseudo-second-order kinetic model, and the equilibrium data were described very well by the Freundlich isotherm model. Furthermore, the as-synthesized adsorbent exhibited excellent regeneration and recyclability while maintaining high adsorption performance after five adsorption/desorption cycles.