Search Results (51)

A simple and innovative synthesis strategy was established to produce polymer microspheres with a distinctive walnut-like morphology, incorporating Fe₃O₄ nanoparticles within their structure. This was achieved through γ-ray-initiated mini-emulsion polymerization. To ensure high encapsulation efficiency, the surface of the Fe₃O₄ nanoparticles was chemically altered to shift their wettability from hydrophilic to hydrophobic, enabling uniform dispersion within the monomer phase before polymerization. The formation of the walnut-like architecture was found to be significantly influenced by both the polymerization dynamics and phase separation, as well as the shrinkage of the crosslinked polymer network formed between the monomer and the resulting polymer. Divinylbenzene (DVB) was chosen as the monomer due to its ability to generate a mechanically stable polymer framework. The γ-ray irradiation effectively initiated polymerization while preserving structural coherence. A detailed analysis using FTIR, SEM, and TEM confirmed the successful fabrication of the Fe₃O₄-loaded polymer microspheres with their characteristic textured surface. Moreover, magnetic characterization via vibrating sample magnetometry (VSM) indicated pronounced superparamagnetic behavior and strong magnetic responsiveness, highlighting the potential of these microspheres for advanced biomedical applications. Full article

A novel approach for synthesizing polymer particles that encapsulate Fe₃O₄ nanoparticles using γ-ray irradiated mini-emulsion polymerization is presented. To achieve high encapsulation efficiency, the surface properties of Fe₃O₄ nanoparticles are modified from hydrophilic to hydrophobic, allowing for effective dispersion in the monomer prior to polymerization. Mini-emulsion techniques have proven essential for forming the encapsulated structure and controlling particle size distribution. γ-ray irradiation initiated radical polymerization and solidified the emulsion structure. Characterization via FTIR, XRD, and TEM confirmed the successful encapsulation of Fe₃O₄ nanoparticles within polymer particles. Magnetic measurements demonstrated superparamagnetic behavior and high magnetic induction, both of which are properties considered advantageous for biomedical applications. Full article

This study investigates the synthesis and application of acrylic–urethane hybrid polymer dispersions as advanced binders for leather finishing. Two polymerization techniques—seeded emulsion and miniemulsion—were used to produce hybrid polymer dispersions by varying the ratios of polyurethane (PU) and acrylic (AC). The synthesized dispersions, i.e., the hybrid polyurethanes, showed stable, uniform particle sizes, inferring good compatibility and interaction between the PU and AC phases, as confirmed by particle sizes, FTIR, and DSC analyses. The performance of the coating on leather surfaces was assessed by using standard physical tests, including rubbing fastness, flexing endurance, water spot resistance, and grain strength. The results showed that the hybrid polymers outperformed their individual PU and AC counterparts, particularly in terms of abrasion resistance and mechanical integrity. Of the two polymerization techniques, the seeded emulsion hybrids exhibited superior coating properties, providing greater resistance to cracking and abrasion under stress, improved grain strength, and better color retention during rubbing tests. These findings highlight the potential of acrylic–urethane hybrids, particularly those prepared via seeded emulsion polymerization, to address the limitations of traditional binders in high-performance leather applications. Full article

The direct acrylation of soybean oil was investigated by the activation of soybean oil’s (SO’s) internal fatty unsaturation with acidic catalysts. The effect of the catalyst and the reactant ratio with respect to the unsaturation and reaction time on the direct acrylation process were explored. ASO (acrylated soybean oil) with acrylation degrees (the number of acrylate molecules introduced in a triglyceride molecule) between 1.6 and 2.55 were obtained. The effect of the ASO acrylation degree on copolymerization processes was investigated. The resulting monomers were successfully copolymerized with meth(acrylate) monomers by the miniemulsion polymerization process, favoring the droplet nucleation mechanism and showing conversions higher than 97%. The acrylic–ASO copolymers presented lower Tg and higher hydrophobicity and oleophobicity than the acrylic copolymer. Full article

This work focuses on the encapsulation of two organic phase change materials (PCMs), hexadecane and octadecane, through the formation of nanocapsules of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) obtained by oxidative polymerization in miniemulsion. The energy storage capacity of nanoparticles is studied by preparing polymer films on supporting substrates. The results indicate that the prepared systems can store and later release thermal energy in the form of latent heat efficiently, which is of vital importance to increase the efficiency of future thermoelectric devices. Full article

The development of a dynamic network for commodity polymer systems via feasible methods has been explored in the context of a society-wide focus on the environment and sustainability. Herein, we demonstrate an adaptive post-curing method used to build a self-healable network of waterborne polyurethane–acrylate (WPUA) composite latex. The composite latex was synthesized via the miniemulsion polymerization of acrylates in the dispersion of waterborne polyurethane (PU), with commercial acetoacetoxyethyl methacrylate (AAEM) serving as the functional monomer. Then, a dynamic disulfide (S–S)-bearing diamine was applied as the crosslinking agent for the post-curing of the hybrid latex via keto-amine condensation, which occurred during the evaporation of water for film formation. It was revealed that the microphase separation in the hybrid films was suppressed by the post-curing network. The mechanical performance exhibited a high reliability as regards the contents of the crosslinking agents. The reversible exchange of S–S bonds meant that the film displayed associative covalent-adaptive networks in the range of medium temperature in stress relaxation tests, and ≥95% recovery in both the stress and the strain was achieved after the cut-off films were self-healed at 70 °C for 2 h. The rebuilding of the network was also illustrated by the >80% recovery in the elongation at break of the films after three crushing–hot pressing cycles. These findings offer valuable insights, not only endowing the traditional WPUA with self-healing and reprocessing properties, but broadening the field of study of dynamic networks to polymer hybrid latex. Full article

In the context of the global COVID-19 pandemic caused by the highly transmissible SARS-CoV-2 virus, molecularly imprinted polymers (MIPs) have emerged as a cutting-edge solution for the specific recognition of the Spike S1 protein, a crucial element in the virus’s cellular entry. This pandemic determined challenges in rapid virus detection, mutation monitoring, and vaccine distribution. MIPs, with their specific binding sites, offer a unique approach to selectively capture and detect the Spike S1 protein, providing a basic start for rapid diagnostics or targeted therapeutics. This work presents the potential of MIPs in solving the complex SARS-CoV-2 problem, highlighting the promising combination of nanotechnology, molecular imprinting, and virology to combat the ongoing global crisis and prepare for future viral threats. Full article

The cross-linked conjugated polymer poly(tetraphenylethene-co-biphenyl) (PTPEBP) nanoparticles were prepared by Suzuki-miniemulsion polymerization. The structure, morphology, and pore characteristics of PTPEBP nanoparticles were characterized by FTIR, NMR, SEM, and nitrogen adsorption and desorption measurements. PTPEBP presents a spherical nanoparticle morphology with a particle size of 56 nm; the specific surface area is 69.1 m²/g, and the distribution of the pore size is centered at about 2.5 nm. Due to the introduction of the tetraphenylethene unit, the fluorescence quantum yield of the PTPEBP nanoparticles reaches 8.14% in aqueous dispersion. Combining the porosity and nanoparticle morphology, the fluorescence sensing detection toward nitroaromatic explosives in the pure aqueous phase has been realized. The Stern–Volmer quenching constant for 2,4,6-trinitrophenol (TNP) detection is 2.50 × 10⁴ M⁻¹, the limit of detection is 1.07 μM, and the limit of quantification is 3.57 μM. Importantly, the detection effect of PTPEBP nanoparticles toward TNP did not change significantly after adding other nitroaromatic compounds, indicating that the anti-interference and selectivity for TNP detection in aqueous media is remarkable. In addition, the spike recovery test demonstrates the potential of PTPEBP nanoparticles for detecting TNP in natural environmental water samples. Full article

Phthalocyanine pigments have many problems in waterborne coating applications because of their low polarity, poor dispersion in water, and easy agglomeration properties. In order to solve these problems, the phthalocyanine pigments were encapsulated with a copolymer of methyl methacrylate (MMA) and butyl acrylate (BA) by a mini-emulsion polymerization method. The pigments are effectively dispersed in water and have good compatibility with the resin. Concerning the bacterial reproduction and growth problem for the waterborne system, the resin-encapsulated phthalocyanine pigments were further grafted with antibacterial polymer poly(N-(2-hydroxyethyl) acrylamide) (PHEAA) on its surface using the photoemulsion polymerization technique. Comprehensive properties, including centrifugal stability and chromaticity change, were studied. The polymer encapsulation improved the centrifugal stability of the pigment. The thermogravimetric results showed that the residual mass of C.I. Pigment Green 7 (52.30%) was higher than that of C.I. Pigment Blue 15:3 (30.06%), and the sublimation fastness of PG7 was higher. The TEM results revealed that the shape of the PG7 after encapsulation and grafting was more regular than that of PB15:3. The L* of the pigment decreased after encapsulation but then increased after further grafting. The phthalocyanine pigment composite latex had good antibacterial properties after the grafting of PHEAA. Full article

Discoloration of wood coatings due to fungal growth negatively affects the aesthetic properties of the coatings, and new ways to control fungal growth on coatings are needed. For this reason, silver nanoparticles (AgNPs) have been incorporated in acrylic latexes as antifungal agents. Using miniemulsion polymerization, latexes were prepared with two types of initiators (hydrophilic and hydrophobic) to assess the influence of the initiator type on AgNPs dispersion, both within the latex particles and the dry film. In addition, the impact of NP dispersion on resistance to black-stain fungi (Aureobasidium pullulans) was also evaluated. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis indicates that acrylic latexes prepared with azobisisobutyronitrile (AIBN) as the initiator contain more AgNPs than those prepared with potassium persulfate (KPS). Cryo-TEM and SEM analyses show that the distribution of the AgNPs within the polymer particles is influenced by the nature of the initiator. When AIBN, a hydrophobic initiator, is used, the AgNPs appear to be closer to the surface of the polymer particles and more evenly distributed. However, the antifungal efficiency of the AgNPs-embedded latexes against A. pullulans is found to be higher when KPS is used, despite this initiator leading to a smaller amount of incorporated AgNPs and a less uniform dispersion of the nanoparticles. Full article

The demand for waterproof leather has been increasing, and environmentally friendly waterproof fatliquors have recently received increasing attention. In this work, two polymer nanoemulsions containing carboxyl groups were synthesized and used as waterproof fatliquors for chrome-tanned leather. First, a reactive emulsifier (C₁₂-Na) was prepared using itaconic anhydride and lauryl alcohol. Subsequently, two polymer nanoemulsions were prepared through mini-emulsion polymerization with C₁₂-Na as the emulsifier, 4,4′-azobis (4-cyanovaleric acid) as the initiator, and lauryl acrylate (LA)/stearyl acrylate (SA) as monomers; these were named PLA and PSA. PLA and PSA were characterized using FT-IR, a Zetasizer, and GPC. It was found that the critical micellar concentration (CMC) of C₁₂-Na was 2.34 mmol/L, which could reduce the surface tension of water to 26.61 mN/m. The average particle sizes of PLA and PSA were 53.39 and 67.90 nm, respectively. The maeser flexes of leather treated with PLA and PSA were 13928 and 19492 at a 5% dosage, respectively, and the contact angles reached 148.4° and 150.3°, respectively; these values were both higher than for a conventional fatliquor. Compared with PLA, the leather treated with PSA exhibited better fullness, and tensile and tearing strength. The prepared nanoemulsions have prospective applications in leather manufacturing as waterproof fatliquors. Full article

In this study, three copolymers of poly(methyl methacrylate) and poly(butyl acrylate) (PMMA-co-PBA) latex containing 1-octyl-3 methylimidazolium hexafluorophosphate (C₈mimPF₆), cellulose nanocrystals (CNCs), and C₈mimPF₆-CNCs were successfully synthesized through mini emulsion polymerization. These novel composites were each coated on mild steel panels and tested for their anti-corrosion performance by immersion of the coated samples in 3.5 wt% sodium chloride (NaCl) solution over a certain period. The synergistic anti-corrosion effects of the C₈mimPF₆-CNCs sample led to the highest coating resistance, charge transfer resistance, and corrosion inhibition efficiency and the lowest diffusion coefficient and corrosion rate. The proposed synergistic mechanism revealed that CNCs enhanced the barrier effect of the coating while C₈mimPF₆ inhibited corrosion when released. Full article

In this study, a novel polymeric nanomaterial was synthesized and characterized, and it its potential usability in hypertension treatment was demonstrated. For these purposes, a poly(hydroxyethyl methacrylate-methacryloylamidophenylalanine)-based polymeric nanomaterial (p(HEMPA)) was synthesized using a mini-emulsion polymerization technique. The nanomaterials were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and zeta size analysis. The synthesized p(HEMPA) nanomaterial had a diameter of about 113 nm. Amlodipine-binding studies were optimized by changing the reaction conditions. Under optimum conditions, amlodipine’s maximum adsorption value (Qmax) of the p(HEMPA) nanopolymer was found to be 145.8 mg/g. In vitro controlled drug release rates of amlodipine, bound to the nanopolymer at the optimum conditions, were studied with the dialysis method in a simulated gastrointestinal system with pH values of 1.2, 6.8 and 7.4. It was found that 99.5% of amlodipine loaded on the nanomaterial was released at pH 7.4 and 72 h. Even after 72 h, no difference was observed in the release of AML. It can be said that the synthesized nanomaterial is suitable for oral amlodipine release. In conclusion, the synthesized nanomaterial was studied for the first time in the literature as a drug delivery system for use in the treatment of hypertension. In addition, AML–p(HEMPA) nanomaterials may enable less frequent drug uptake, have higher bioavailability, and allow for prolonged release with minimal side effects. Full article

In this study, ligand-free nanogels (LFNGs) as potential antivenom mimics were developed with the aim of preventing hypersensitivity and other side effects following massive bee attacks. For this purpose, poly (ethylene glycol) diacrylate was chosen as a main synthetic biocompatible matrix to prepare the experimental LFNGs. The overall concept uses inverse mini-emulsion polymerization as the main route to deliver nanogel caps with complementary cavities for phospholipase A2 (PLA2) from bee venom, created artificially with the use of molecular imprinting (MI) technologies. The morphology and the hydrodynamic features of the nanogels were confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis. The following rebinding experiments evidenced the specificity of molecularly imprinted LFNG for PLA2, with rebinding capacities up to 8-fold higher compared to the reference non-imprinted nanogel, while the in vitro binding assays of PLA2 from commercial bee venom indicated that such synthetic nanogels are able to recognize and retain the targeted PLA2 enzyme. The results were finally collaborated with in vitro cell-viability experiments and resulted in a strong belief that such LFNG may actually be used for future therapies against bee envenomation. Full article

The sensitive and selective detection of nitroaromatic explosives is of great significance to national security and human health. Herein, the novel linear polymer l-PAnTPE and cross-linked polymer PAnTPE nanoparticles based on anthracene and tetraphenylethene groups were designed and successfully synthesized via Suzuki-miniemulsion polymerization. The particle sizes of the polymers are around 73 nm, making them well dispersible in water. The cross-linked polymer PAnTPE exhibits porous structure, which is beneficial for the diffusion/adsorption of analytes. The fluorescence sensing towards nitroaromatics was performed in the aqueous phase, and l-PAnTPE and PAnTPE nanoparticles showed different quenching degree towards different nitroaromatics. Among them, the quenching constant K_SV values of l-PAnTPE and PAnTPE towards 2,4,6-trinitrophenol (TNP) reach 1.8 × 10⁴ M⁻¹ and 4.0 × 10⁴ M⁻¹, respectively, which are 1–2 orders of magnitude higher than other nitroaromatic explosives, thus demonstrating the high sensitivity and selectivity of TNP detection in the aqueous phase. The sensing mechanism was further discussed to clarify this phenomenon by analyzing UV–Vis absorption, excitation, fluorescence spectra, cyclic voltammograms and fluorescence decay measurements. In addition, the paper strips tests exhibit that l-PAnTPE and PAnTPE have great potential in the application of fast, low-cost and on-site nitroaromatics detection. Full article