The aim of this work was to synthesise highly open porous low-density polymer foams with superior mechanical properties by the polymerisation of the organic phase of concentrated emulsions. The ...continuous organic phase of the concentrated emulsion template occupying up to 40vol% was polymerised leading to polymer foams with much improved mechanical properties. The Young's modulus as well as the crush strength of the foams was further increased dramatically by reinforcing the polymer phase with nanosized silica particles. To ensure that the silica particles were covalently incorporated into the polymer network, methacryloxypropyltrimethoxysilane (MPS) was added to the formulation, which reacts with the silica via hydrolysis reactions. The Young's modulus of silica reinforced foams increased by 280% and the crush strength by 218% in comparison to foams without reinforcement.
•The resin with a well-interconnected pore structure was fabricated for oil sorption.•Only 5min was needed for the resin to reach absorption saturation.•The porous resin could effectively remove ...floating oil on water surface.•The porous resin exhibits high oil retention and good reusability.
To achieve the dual features of fast oil absorption rate and high oil absorbency for the practical application in emergency treatment of spilled chemical pollutants, hierarchical porous resins were synthesized. The polymerization of high internal phase emulsion was applied to fabricate the porous structure for the purpose of high oil absorbency. Polymeric porogens were proposed to adjust the second-order or interconnected pore structure for fast oil absorption rate. SEM revealed the hierarchical porous structure. Molecular weight and dose of polymeric porogen were investigated for the effect on the formation of porous structure and absorption features. Optimized resins have 31.5g/g or 17.1g/g absorbency for chloroform and toluene, respectively, and only 5min is needed to reach their saturation absorption. Besides, the porous resins demonstrated high oil retention under pressure. The absorption/desorption cycling results revealed the high repeatability of recovered resins. All these tests predicted the potential applications of porous resins of this kind particularly in the emergency treatment of oil and chemical pollution.
Monolithic porous copolymers with 3D structure were prepared via CO2‐in‐water high internal phase emulsions template by graft copolymerization of sodium methacrylate (MAANa) on to methyl cellulose ...(MC) backbone. The yielded copolymer monoliths are characterized by Fourier transform infrared spectra, scanning electron microscopy (SEM), and mechanical instrument, the swelling degree of MC‐g‐PMAANa monoliths with different crosslinker in diverse pH were investigated. The adsorption performance of monolith to Cu(II) were conducted to explore its adsorption capacity to heavy metal ions from the wastewater. Then, a strategy of in situ growth of metal‐organic frameworks (MOFs) on MC‐g‐PMAANa that adsorbed with metal ions was proposed first. The X‐ray powder diffraction, SEM, and Brunauer‐Emmett‐Teller (BET) surface area result of MC‐g‐PMAANa/MOFs composites indicated that the MOFs nanoparticles were grown uniformly on the monolith wall without destroying its original 3D porous structure. Compared with MOFs nanoparticle, MC‐g‐PMAANa/MOFs composites have advantages of easy operation and handle, which more conform to practical application. Furthermore, the antibacterial activity of MC‐g‐PMAANa/MOFs was evaluated by disk agar diffusion and optical density methods. In addition, MC‐g‐PMAANa/Cu‐BTC composite was applied to dye adsorption, which has proved the underlying application of such composites in dye removal.
The synthesis of glycidyl methacrylate–based polyHIPEs by free-radical polymerization in the presence of 1,8-diaminoctane or tris(2-aminoethyl)amine-enriched high internal phase emulsions is ...presented. This innovative “one-pot” synthetic route was developed to produce the so-called in situ hyper-cross-linked polyHIPEs without the use of any additional catalyst, cross-linker, or solvent. In situ hyper-cross-linking was performed through the amine-epoxy reaction before the gel point had been reached, resulting in the formation of the β-amino alcohol derivatives that represent cross-linking knots between the neighboring epoxy repeating units within the poly (glycidyl methacrylate) backbone. In this way, the volume of the mesopores smaller than 3 nm significantly increased. Thus, by changing the amounts of ethylene glycol dimethacrylate and amines in the HIPE templates, the porous structure and the pore volume of the hyper-cross-linked polyHIPEs were systematically altered in order to amplify the polyHIPE’s specific surface area.
Herein, the starch nanocrystal/tannic acid (ST) complex particles, which were prepared based on the hydrogen bond between starch nanocrystal (SNC) and tannic acid (TA), were successfully used to ...stabilize the HIPPE gels. The optimal TA concentration of the ST complex particles resulted in better water dispersibility, surface wettability, and interfacial activity as compared to SNC. The hydrogen bond responsible for the formation of ST complex particles and subsequent stable emulsions was demonstrated by varying the pH and ionic strength of the aqueous phase. Notably, the HIPPE gels stabilized via the ST complex particles can maintain long-term stability for up to three months. The HIPPEs stabilized via the ST complex particles all displayed gel-like features and had smaller droplets and denser droplet networks than the SNC-stabilized HIPPEs. The rheological behavior of HIPPE gels stabilized via the ST complex particles can be readily changed by tuning the mass ratio of SNC and TA as well as pH. Finally, the prepared HIPPE gels used to effectively protect encapsulated
-carotene against high temperatures and ultraviolet radiation and its controllable release at room temperature were demonstrated. It is anticipated that the aforementioned findings will provide new perspectives on the preparation of Pickering emulsion for delivery systems.
Because of the nontoxic solvents contained in CO2-in-water emulsions, porous polymer composites templated from these emulsions are conducive for bio-applications. Herein, bio-active rod-like ...calcium-organic framworks (Ca-BDC MOFs, BDC= 1,4-benzenedicarboxylate anion) particles co-stabilized CO2-in-water high internal phase emulsion (C/W HIPE) in the presence of polyvinyl alcohol (PVA) is first presented. After curing of the continuous phase, followed by releasing CO2, integral 3D macro-porous Ca-BDC monolith and Ca-BDC/Poly(2-hydroxyethyl methacrylate-co-acrylamide) HIPEs monolithic composites Ca-BDC/P(AM-co-HEMA)HIPEs with open-cell macro-porous structures were successfully prepared. The pore structure of these porous composite can be tuned by means of tailoring the Ca-BDC dosage, carbon dioxide pressure, and continuous phase volume fractions in corresponding C/W HIPEs. Results of bio-compatibility tests show that these Ca-BDC/P(AM-co-HEMA)HIPEs monoliths have non-cytotoxicity on HepG2 cells; also, the E. coli can grow either on the surfaces or inside these monoliths. Furthermore, immobilization of β-amylase on these porous composite presents that β-amylase can be well-anchored into the porous polymer composites, its catalytic activity can be maintained even after 10 cycles. This work combined bio-active MOFs Ca-BDC, bio-compatible open-cell macroporous polymer PAM-co-HEMA and green C/W HIPEs to present a novel and facile way to prepare interconnected macro-porous MOFs/polymer composites. Compared with the existing other well-known materials such as hydrogels, these porous composites possess well-defined tunable pore structures and superior bio-activity, thereby have promising applications in bio-tissue engineering, food, and pharmaceutical.
•Two kinds of hydrophobic polymer foam catalysts were prepared by HIPEs.•Cr3+-HPFs-1-H+ and HPFs-1-H+ possess Lewis–Brønsted double acid sites.•Lewis and Brønsted acid sites could be adjusted.•This ...work opens up a simple route to synthesis catalysts with double acid sites.
Herein we reported a simple and novel synthetic strategy for the fabrication of two kinds of hydrophobic polymer foam catalysts (i.e. Cr3+-HPFs-1-H+ and HPFs-1-H+) with hierarchical porous structure, inhomogeneous acidic composition and Lewis–Brønsted double acid sites distributed on the surface, which was used to one-pot conversion of carbohydrate (such as cellulose, glucose and fructose) to a key chemical platform (i.e. 5-hydroxymethylfurfural, HMF). The water-in-oil (W/O) high internal phase emulsions (HIPEs), stabilized by both Span 80 and acidic prepolymers as analogous particles offered the acidic actives, were used as the template for simultaneous polymerization of oil phase in the presence of divinylbenzene (DVB) and styrene (St). After subsequent ion-exchange process, Lewis and Brønsted acid sites derived from exchanged Cr3+ and H+ ion were both fixed on the surface of cell of the catalysts. The HPFs-1-H+ and Cr3+-HPFs-1-H+ had similar hierarchical porous, hydrophobic surface and acid sites (HPFs-1-H+ with macropores ranging from 0.1μm to 20μm, uniform mesopores in 14.4nm, water contact angle of 122° and 0.614mmolg−1 of Brønsted acid sites, as well as Cr3+-HPFs-1-H+ with macropores ranging from 0.1μm to 20μm, uniform mesopores in 13.3nm, water contact angle of 136° and 0.638mmolg−1 of Lewis–Brønsted acid sites). It was confirmed that Lewis acid sites of catalyst had a slight influence on the HMF yield of fructose came from the function of Brønsted acid sites, and Lewis acid sites were in favor of improving the HMF yield from cellulose and glucose. This work opens up a simple and novel route to synthesize multifunctional polymeric catalysts for efficient one-pot conversion of carbohydrate to HMF.
Stable oil-in-water (o/w) Pickering high internal phase emulsions (HIPEs) having an internal phase of up to 95 vol% were prepared with a low-energy emulsification method. A poly(urethane urea) (PUU) ...aqueous nanodispersion was used as aqueous phase. The PUU nanoparticles of the aqueous nanodispersion acted as a mechanical barrier, and prevented droplet coalescence in the Pickering HIPEs. In addition, open porous hydrophilic polymer foams were obtained by polymerization of the Pickering HIPEs, and the morphology of the foams were tailored by changing the oil:water ratio, PUU nanoparticle and NaCl concentrations. The method used herein provides a simple way to prepare morphology controlled hydrophilic polymer foams using o/w Pickering HIPEs as template.
Display omitted
In this work, soluble soybean polysaccharides (SSPS) were employed together with multifrequency ultrasound to fabricate zein nanocomposites which were conducive to enhancing the stability of high ...internal phase emulsions (HIPEs). Compared with non-ultrasonic treated zein colloidal particle samples (132.23 ± 0.85 nm), the zein nanoparticles samples induced by dual-frequency ultrasound exhibited a smaller particle size (114.54 ± 0.23 nm). Furthermore, the particle size of the zein composite nanoparticles (256.5 ± 4.81) remarkably increased with SPSS coating, consequently leading to larger fluorescence intensity together with lower zeta-potential (−21.90 ± 0.46 mv) and surface hydrophobicity (4992.15 ± 37.28). Meanwhile, zein-SSPS composite nanoparticles induced by DFU showed remarkably enhanced thermal stability. Fourier transform infrared (FTIR) spectroscopy and Circular dichroism (CD) spectroscopy were also used to characterize zein-SSPS composite nanoparticles. The results confirmed that DFU combined with SSPS treatment significantly increased β-sheets (from 12.60% ± 0.25 b to 21.53% ± 0.37 c) and reduced α-helix content (34.83% ± 0.71 b to 23.86% ± 0.66 a) remarkably. Notably, HIPEs prepared from zein-SSPS nanocomposites induced by dual-frequency simultaneous ultrasound (DFU) at 40/60 kHz showed better storage stability. HIPEs stabilized by DFU induced zein-SSPS nanoparticles exhibited higher storage modulus (G′) and loss modulus (G″), leading to lower fluidity, together with better stability contributing to the water-binding capacity and three-dimensional (3D) network structure of the HIPEs emulsion. The findings of this study indicate that this method can be utilized and integrated to further extend the application of zein and SSPS and explore HIPEs.
High internal phase emulsions (HIPEs) have been introduced as an alternative to liquid oil to improve the quality of air-fried seafood products. In this study, the effect of HIPE coating compared to ...that of liquid oil or no oil on air-fried squid quality was investigated. The exudation content of oil droplets (ranging from 0.021 ± 0.002 to 0.067 ± 0.005 g) and water loss (7.19 g) in air-fried squid with HIPE coating were significantly reduced compared to those with liquid oil coating. Owing to the homogeneous HIPE coating, the air-fried squid possessed acceptable textural properties (hardness, 2845.04 ± 570.48 g; chewiness, 2405.77 ± 203.55 g), excellent color, and a fried-like flavor, when compared to air-fried squid with or without liquid oil. Interestingly, there was a lower content (5.90 ± 0.18 ng/g) of heterocyclic aromatic amines in air-fried squid with HIPE coating than in those with liquid oil coating (20.18 ± 0.26 ng/g) or without oil coating (21.25 ± 0.50 ng/g). In summary, HIPE, as a novel oil medium, is advantageous for the development of air-frying products.
PDF
