A cellulose aerogel with very low overall density is fabricated by freeze-drying aqueous cellulose solution. A hydrophobic/oleophilic cellulose aerogel is further fabricated by coating the cellulose aerogel with hexyltrimethoxysilane-modified SiO2 nanoparticles. The features of the developed hydrophobic/oleophilic cellulose aerogel are characterized with density and porosity measurement, infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and contact angle measurement. Finally, the oil absorption performance of the developed hydrophobic/oleophilic cellulose aerogel is investigated. The results show that SiO2 nanoparticles have been successfully loaded on the surface of the aerogel backbone after fulfillment of fabrication, and the surface of the aerogel turns to be hydrophobic/oleophilic (water contact angle 131° and oil contact angle 0°). The oil absorption experiment results show that the absorption capacity for organic solvents is from 10 to 21 times the initial aerogel weight, depending on the density of the absorbed organic solvents. In addition, the aerogel still maintains good stability in high temperature, strong acid or strong base conditions. Furthermore, the aerogel also shows good performance in separating oil from oil–water mixtures. This hydrophobic/oleophilic cellulose aerogel can be a promising choice for remedying water pollution caused by oil contamination.

Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) as a kind of low dielectric polymer has been applied in telecommunications. However, developing PPO based thermosetting resins with good comprehensive properties is highly challenging. Herein, an interpenetrating polymer network (IPN) design strategy for the preparation of methacrylate-terminated oligo(2,6-dimethyl-1,4-phenylene oxide) (SA9000) based thermosetting resins is presented. Two series of prepolymers are prepared by blending bisphenol A/furfurylamine benzoxazine (B-f) or bisphenol A/aniline benzoxazine (B-a) with SA9000. Then the IPN films are fabricated by the programmed temperature rising method with simultaneous polymerization reactions of both SA9000 and benzoxazines. Owing to the intermolecular interactions between SA9000 and benzoxazines, the polymerization peak temperatures of all prepolymers are lower than those of SA9000 and benzoxazines. In comparison with B-a based films, B-f/SA9000 films display better miscibility and higher thermal resistances over the entire composition range, due to the strengthened hydrogen bonding and higher cross-linking density resulting from the presence of furan ring of B-f. Specifically, B-f/SA9000 films possess the advantages of low dielectric constants (2.296–2.475) and low-loss grade dielectric losses (0.00550–0.00683) at 10 GHz. The current work provides a simple and effective path for the fabrication of high-performance thermosetting PPO resins based on benzoxazine chemistry and IPN structure design.

Wenlong Yang and Yu Wang designed the cover image that showed the interface structure of the polyimide/silica composites. The functional groups on the surface of nanofillers could significantly improve the organic-inorganic interfacial compatibility and the interfacial load transfer efficiency. The static dielectric permittivity of PI-based composites could be elevated by enhancing intrinsic polarization. These results provided an understanding of the atomic-scale interfacial structures, which was beneficial for the design and preparation of the nanocomposites with superior dielectric and mechanical performances. DOI: 10.1002/app.54321

A self-cleaning mixed-matrix membrane was successfully developed and fabricated using the reverse thermally induced phase separation (RTIPS) method, incorporating modified particles. To achieve this, DA@CuFe2O4 particles were prepared by modifying CuFe2O4 with dopamine (DA) and then fed into the membrane matrix. The RTIPS method was employed to create hydrophilic membranes that exhibited remarkable stability and toughness. X-ray diffraction, Fourier-transform infrared (FTIR), transmission electron microscopy, and thermogravimetric analysis results showed that the particles were successfully modified. XPS, scanning electron microscopy, and FTIR proved that the modified particles were introduced into the film. The EDS spectra also showed that the self-made CuFe2O4 particles with DA adsorbed on the surface were uniformly distributed in the organic matter. In addition, the results of the contact angle characterization, tensile test, water flux test, oil–water separation test, and cycle test showed that the material with a high water flux (1707.78 L/m2 h) and removal rate of >99.9% has good wettability, mechanical properties, corrosion resistance, and stain resistance. In addition, the photocatalytic performance of the modified membranes was demonstrated by studying the degradation of pollutants under visible light. Through photocatalysis, the membrane material obtained a higher utilization rate, which provided a new attempt to solve the membrane separation technology in the field of oily wastewater treatment.

In this work, a novel functional polylactic acid (PLA) was prepared by melt blending using epoxy Joncryl ADR 4468 (ADR) as chain extender. The effects of the epoxy chain expander ADR on the molecular structure, crystallization properties, rheological properties, and mechanical properties of PLA were studied. Furthermore, the chain expansion mechanism was analyzed. It was found that the epoxy group of the epoxy chain extender reacted with the terminal hydroxyl and terminal carboxyl groups of PLA in the molten state, thus significantly increasing the molecular weight of PLA. Meanwhile, the weight average molecular weight of PLA increased by 42.51% when the maximum additional amount of epoxy chain extender was 1.2 wt%. The dynamic rheological experiments also confirmed that ADR can effectively improve the storage modulus, loss modulus and complex viscosity of PLA systems and the Cole-Cole diagram reveals the branched structure of PLA chain expansion systems. The formation of this branched structure will destroy the regularity of the PLA chain, reduce the crystallization capacity of PLA, and increase the cold crystallization temperature of the PLA system. Through SEM and mechanical property tests, it is found that the addition of ADR makes the molecular chain form a micro-crosslinked structure, thereby improving the tensile strength of PLA. Therefore, the molecular structure of PLA was effectively regulated and exhibited a promising performance, which greatly expands the potential applications of PLA.

The application of highly filled composites is limited by their poor processing and rheological properties due to the high loading of fillers. One possible solution to this problem is to use maleic anhydride grafted polypropylene (MAPP) with high melt index as compatibilizer and lubricant. Herein, magnesium hydroxide (MH)/linear low-density polyethylene (LLDPE) composites with 60 wt% of MH were prepared using MAPP with three different melt flow indexes (MFI). The equilibrium torque and melt flow index tests show that the addition of MAPP with high MFI significantly improves the processability and flowability of MH/MAPP/LLDPE composites. The rheological studies show that it also leads to a substantial reduction in the viscosity and therefore MH/MAPP/LLDPE composites exhibit more solid-like responses. The scanning electron microscopy shows that a transition layer is formed at the MH-LLDPE interface. The flame retardancy test shows that the addition of MAPP slightly reduces the flame retardancy of the composites as evidenced by the reduced limiting oxygen index and increased total heat release. Cone calorimeter test shows that the simultaneous addition of MH and MAPP has a synergistic smoke suppression effect.

Arsenate species are hazardous, toxic, and carcinogenic, they pose a significant risk to human health. In this finding, we have fabricated the Chitosan, β-cyclodextrin and Fe2O3 (CS-βCD-Fe2O3) composite nanofibers through electrospinning for arsenic (As-III) adsorption in a lab-scale designed continuous filtration system. The SEM images have shown the bead free morphology of the prepared nanofibers and chemical composition was characterized by Fourier transforms infrared (FTIR) spectroscopy. The experimental data supported monolayer adsorptions by having a good fit to the Langmuir model. Further, kinetic studies have been conducted to illustrate the adsorption of As-III onto CS-βCD-Fe2O3. The CS-βCD-Fe2O3 nanofibers at neutral pH have shown 83% adsorption efficiency of As-III in the batch experiments and 72% in continuous filtration system with a flow rate of 660 mL/h. Additionally, the reusability of the nanofibers was performed, and 60% adsorption efficiency was achieved up to the 5th cycle for batch adsorption. Our prepared composite CS-βCD-Fe2O3 nanofibers could be used in both batch adsorption and continuous filtration system for removal of As-III from aqueous solution.

The carbon fibers were oxidized with concentrated hydrochloric acid, and subsequently modified in two steps. First, the oxidized carbon fibers were grafted with γ-aminopropyltriethoxysilane (KH550) with the purpose of building a platform on the fiber surface, then the epoxy functionalized elastomer (ethylene-vinyl acetate-glycidyl methacrylate terpolymer, EVMG) was grafted on the carbon fiber surface. Chloroprene rubber/natural rubber/carbon fiber (CR/NR/CF) composites were prepared by mechanical blending process. Carbon fibers were characterized by different techniques such as X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA). The results show that EVMG can enhance the interface adhesion between fiber and rubber. It was observed that the surface of the carbon fiber is covered with a layer of the macromolecular film by EVMG, which increases the surface roughness and introduces epoxy groups. On the one hand, carbon fiber and rubber can be entangled through macromolecular chains, and on the other hand, interfacial bonding can be enhanced by chemical interactions. Furthermore, modification by EVMG impacted tensile strength of CF composite increase by 11.05%, the 300% constant tensile stress increased by 21.87%, and the wear resistance increased by 29.8%, respectively.

Applications of poly(vinyl alcohol) (PVOH) are largely limited due to its poor flame resistance. In this work, organosolubility, and flame resistance are imparted to PVOH through green chemical transformation using dichloroacetic acid (DCAA). Unlike the conventional solvent-based strategies, PVOH was modified by simply mixing it with DCAA and heating the mixture without employing any additional reagents/catalysts/solvents. This resulted in the formation of a random copolymer, poly(vinyl alcohol-co-vinyl dichloroacetate), which was not soluble in water but was soluble in organic solvents such as acetone, methanol, and dimethylsulfoxide. Furthermore, the copolymer was inherently self-extinguishing, and did not melt drip or show glowing combustion. Additionally, dummy currency notes coated with this copolymer displayed exceptional self-extinguishing and non-glowing properties when removed from the flame, proving the copolymer's suitability for flame-retardant sizing/coating applications.

A multifunctional sodium alginate/polyacrylamide/titanium dioxide (SA/PAM/TiO2) double network composite hydrogel was successfully prepared by sunlight-induced polymerization and ionic cross-linking method and the relationship between its structure and properties was studied. During the polymerization process, TiO2 is used as an initiator to promote the polymerization and is homogeneously immobilized on the three-dimensional double network hydrogel matrix as the active component of photo-catalysis. The dual network structure and highly hydrophilic functional groups in the structure improves the adsorption capacities of the hydrogel and photocatalytic performance of the catalyst by avoiding the aggregation of TiO2. The influences of different factors, such as the amount of cross-linker, monomer ratio, titanium dioxide content, and exposure time, on the swelling properties of the hydrogel during the reaction process were investigated. The effects of titanium dioxide content, pH value, and initial concentration of methyl orange solution on the adsorption properties and photocatalytic performance of the hydrogel were also examined. In addition, the environmental applications of the material as a reusable adsorbent and an effective photo-catalyst for the treatment of dyes were explored. The hydrogel possesses excellent mechanical properties and stability and was recycled for 10 times without any significant decrease in photocatalytic efficiency.

The rapid development of the electronic packaging industry has necessitated the production of epoxy resin insulation materials with high heat resistance and low water absorption. In this study a new cross-linking composite composed of polyhedral oligomeric silsesquioxane (POSS) functionalized with isocyanate groups and epoxy resin (EP) containing phenolic hydroxyl groups. By employing an isocyanate-hydroxyl process, the cage structure of Ph7POSS with isocyanate functionalization (MP) can be suspended on EP, leading to a significant improvement in the thermal and moisture resistance of the MP/EP composite. Our DSC and TGA studies revealed that the addition of 3% MP to the epoxy resin increased the glass transition temperature by 27.1°C and raised the initial thermal breakdown temperature to 334.5°C. We also utilized a novel quartz crystal microbalance (QCM) technique to continuously monitor the moisture resistance of the composite, and our results showed that the composite absorbed only 0.03% of water. Moreover, the porosity and cross-linking of the POSS molecules further restricted the movement of the polymer chains, thereby reducing the dielectric constant and dielectric loss of the composite. Consequently, the MP-modified epoxy composites exhibit excellent properties, which suggest promising applications in the field of electronic packaging.

Hand or surface sanitizers are all liquid-based products which can be mainly categorized as alcohol or non-alcohol based. The constant release of highly persistent disinfectants and chemicals is hazardous to the environment and human health. Herein, a new concept of solid elastomer sanitizer with inherent fast-killing antimicrobial property is described. Silicone (PDMS) was chosen as the elastomer where the active antimicrobial component of imidazolium polymer (PIM) was carefully modified and incorporated into the PDMS matrix through strong covalent bonds. This chemically bonded antimicrobial component within PDMS acts via release-on-demand model which allows for the long-term reusability of the material. The resulting material can serve as a reusable solid sanitizer that is toxic-free and skin-friendly with fast-killing property. It was proven to sanitize our hands or surfaces and kill microbes within 30–60 s of contact, including ESKAPE pathogens, bacteria, fungi and MS2 bacteriophage. This new concept of solid sanitizer methodology will provide an interesting insight and infinite possibilities for extending to other types of elastomers with suitable or tunable antimicrobial components. This also helps to provide a safer and greener sanitizing model which can dramatically reduce the usage and/or release of disinfectants or harmful chemicals to the environment. The possibilities of extending to other elastomers also widen its potential applications.

This study endeavors to augment the antibacterial and anti-biofouling properties of thin-film composite polyamide membranes by subjecting them to modification with antibacterial chitosan and silver nanoparticle materials through the UV-induced graft polymerization technique. Various surface assessment methods were employed, and the efficiency of the membrane performance was demonstrated through the flux and the retention of the filtration process, which used calcium chloride as the foulant. Antibacterial, antifouling, and anti-biofouling capabilities were assessed through several tests. The findings revealed that the chitosan/silver nanoparticles-grafted membranes exhibited superior antibacterial and anti-biofouling abilities with consistent flux and enhanced retention, underscoring the prospective implementation of this approach in filtration systems to curtail biofouling and bolster overall efficacy.

Metal–organic frameworks (MOFs) are efficient adsorbents for the removal of hazardous materials. An MOF based on 1,3,5-benzenetricarboxylic acid (BTC), Cu3(BTC)2, is prepared via phase separation using supercritical CO2 (scCO2) as a nonsolvent for the polymer solution. The prepared MOF is then loaded onto microporous polystyrene membranes. To evaluate the performance of Cu3(BTC)2-loaded microporous polystyrene membranes for pollutant removal from water, they are tested for the separation of methylene blue (MB) dye from an aqueous solution. Prior to the preparation of the Cu3(BTC)2-loaded microporous polystyrene membranes, Cu3(BTC)2 is activated with scCO2. After the activation with scCO2, the internal surface area of Cu3(BTC)2 and its MB adsorption increase. A toluene solution of polystyrene containing Cu3(BTC)2 particles is prepared, and scCO2 is introduced to induce the phase separation of the polymer solution. A Cu3(BTC)2-loaded microporous polystyrene membrane is obtained without the collapse of the structure after the release of the CO2 pressure. MB can be readily and rapidly removed from aqueous solutions using Cu3(BTC)2-loaded microporous polystyrene membranes. The removal efficiencies for aqueous MB solution were high, and removal efficiencies reached 92.8%.

Thermosensitive polymers based on poly(N-isopropylacrylamide) (pNIPAM) have been widely evaluated in a variety of biomedical applications due to their particular thermal behavior in aqueous solutions. Despite this, few works have focused on the complementary analysis of the thermal transitions of pNIPAM polymers in linear and crosslinked form. In this work, linear and crosslinked poly(N-isopropylacrylamide-co-acrylic acid) p(NIPAM-co-AA) copolymers were synthesized at similar NIPAM/AA feed composition and their thermosensitive behavior was studied by turbidimetric methods, FTIR spectroscopy analysis, and temperature-dependent swelling measurements. The intermolecular crosslinking hindered the hydrophobic aggregation of chain segments, leading to higher transition temperatures of synthesized polymers. AA units promoted the intersegment hydrogen bonds during heating and strengthened the hydrogen bond interactions water-network. The effect of the thermosensitive behavior of p(NIPAM-co-AA) copolymer on curcumin (CUR) release kinetic was also studied. The low uptake level of p(NIPAM-co-AA) hydrogel, partially shrunken at 37°C, produced a CUR sustained delivery, reaching the release equilibrium state up to 18 h. Hydrogels of p(NIPAM-co-AA) with a suitable composition exhibited a promising performance for the CUR controlled delivery at physiological conditions.

A kind of the epoxy and phenyl groups-containing POSS of the regular cage of 16 silicon atoms (EPHPOSS) was synthesized successfully via the hydrolysis-condensation reaction of phenyltrimethoxysilane and 2-(3,4-glycidoxypropyl) propyltrimethoxysilane, and its chemical structure was characterized. To improve the comprehensive performances of the epoxy resin (EP), EPHPOSS in different ratios was incorporated into the EP by thermal curing technology. It is obtained that the EPHPOSS has a homogeneous dispersion in the EP composites and plays an important role in enhancing the bending strength and thermal properties of the EP composites. The EP composite with 10 wt% EPHPOSS has a limiting oxygen index (LOI) value of 27.8%, higher than the LOI of 23.2% of the pure EP. The peak of heat release rate, total heat release, and total smoke release of the EP composites with the EPHPOSS are reduced obviously. In flame retardant mechanism of the EPHPOSS on the EP, the microstructures of the burning char and TG-FTIR of the EP composites were achieved, it is suggested that the EPHPOSS promotes the formation of compact and continuous char layers and reduces the production of the organic combustible gases.

In this study, a novel hydrogel ink made from gelatin and tragacanth gum was prepared. Two additives and a crosslinking agent were added to improve the viscoelastic properties of the material during gelation and its printability. Alginic acid was introduced as a crosslinking agent along with additives such as rice starch and halloysite nanotubes (HNT). Two rheological measurement modes, rotational and oscillatory, were utilized to measure the steady state viscosity and complex moduli, respectively. Auxiliary measurements such as Fourier-transform spectroscopy infrared and gel permeation chromatography were implemented to determine the bonds formed and the molecular weight of gelatin and tragacanth gum, respectively. We have demonstrated how these additives can affect fluid uptake by examining them in water at ambient temperature and also in 1× PBS at both ambient and normal body temperatures. The printability was analyzed by the grid pattern dispensed by interconnected filaments. It was observed that the sample containing HNT and rice starch show the best properties. The hydrogel nanocomposite, unlike the pure gelatin films, retains water and buffer solution for 72 h with minimum changes. Moreover, the printability criterion (Pr) was improved from 0.3 for pure gelatin to about 1 for the sample containing alginate, HNT, and rice starch.

Oily particulate matter pollution and bacteria pose a serious threat to human health and have drawn widespread attention. Herein, an Ag-doped nylon 6 multi-stage structured antibacterial nanofiber membrane (PA6&Ag MSNM) for effective air filtration of fine oily particulate matters was fabricated by adding a certain amount of tetrabutylammonium hexafluorophosphate (TBAHP) and silver nitrate (AgNO3) into PA6 solution via one-step electrospinning. The fabricated PA6&Ag MSNM is composed of coarse trunk fibers and fine branching fibers, which exhibits high filtration efficiency for oily particulate matters and low pressure drop, with an average filtration efficiency of 99.92% for oily particles of 0.20 ~ 4.59 μm and a low pressure drop of 386 Pa. In addition, the fiber membranes possesses excellent antibacterial properties due to the doping of Ag. The prepared multi-stage electrospun nanofiber membrane may provide a versatile strategy for designing new antibacterial air filtration materials, which would have broad application prospects.

In this study, the combinations of phosphorous-containing fire retardants such as triethyl phosphate, oligomeric triethyl phosphate, diethyl ethyl phosphonate, diethyl hydroxymethyl phosphonate, ammonium polyphosphate, and smoke suppressant zinc borate were used as additives in order to produce non-toxic smoke suppressant and fire-retardant rigid polyurethane-polyisocyanurate (PIR) foams. Flame height and smoke density of polyurethane-polyisocyanurate foam decreased by incorporating different combinations of combustion modifiers in PIR formulations. The smoke suppressant was zinc borate. The combination of zinc borate with triethyl phosphate, oligomeric triethyl phosphate, and diethyl hydroxymethyl phosphonate resulted in a good synergy. The cone calorimeter analysis showed that the best combinations were zinc borate (10.1%) and triethyl phosphate (13.7%), or zinc borate (10.1%), triethyl phosphate (6.9%), and oligomeric triethyl phosphate (7%) and they decreased the burning and smoke formation rate of PIR foam. These combinations may be applied to produce fire-retardant PIR foam in the industry.

Modification with nanoparticles is an effective way of overcoming the inherent defects of high-density polyethylene (HDPE). However, the uniform dispersion of nanoparticles in the polymer matrix is the key point of this method. Here, natural rubber latex (NRL) was used for the auxiliary dispersion of self-made nano zinc oxide (nano-ZnO) to realize the uniform dispersion of nano-ZnO in HDPE. The HDPE-based nanocomposite with excellent thermo-oxidative aging resistance, mechanical properties and electrical insulation properties were successfully prepared. Three weight percent of nano-ZnO was uniformly dispersed in HDPE (HLZ3), which not only synergistically toughened HDPE with natural rubber (coagulated natural rubber latex, NR), but also maintained the tensile strength of the matrix. Moreover, the interfacial interactions between nanoparticles and polymers improved the alternating current (AC) breakdown strength and volume resistivity of the HDPE matrix. After aging treatment, the crystallinity of HLZ3 decreased very little, and its carbonyl index was much smaller than that of pure HDPE. Therefore, it has the best performance retention rate. This nanoparticle dispersion method has certain reference significance. And this HDPE-based nanocomposite material is expected to be used in the outer sheath of cables.