Search Results (56)

The aim of this research was to evaluate the efficacy of water-soluble epoxy resin (ER) in regard to stabilising clay soils, specifically for the design of column-type reinforcement in soft ground. An extensive laboratory program was conducted to assess the mechanical enhancement of a silty clay soil via ER, both as a standalone stabiliser and in combination with cement, bentonite, and sodium polyacrylate (PA). In addition, the study investigated the impacts of thermal stabilisation and electro-osmotic dewatering on resin–soil specimens. Specimens stabilised solely with ER exhibited poor strength development due to the inhibition of polymerisation by water. The addition of bentonite at low concentrations resulted in low early strength development and a moderate increase in the final strength. The use of cement provided the most significant strength gains, which were further enhanced by optimising the dosage of PA, although an excessive PA content significantly reduced the strength properties. In terms of physical treatments, thermal stabilisation at an optimal temperature of 60 °C for 24 h substantially improved the performance of ER. Electro-osmotic treatment accelerated the development of early strength but failed to provide appreciable strength improvement, and resulted in brittle behaviour and reduced toughness in the later stages (90–180 days). These findings offer critical guidelines for optimising mix designs and treatment protocols for geotechnical ground improvement projects. Full article

The objective of this in vitro study was to investigate the effects of dentin pretreatment protocols and thermocycling on the shear bond strength (SBS) of a self-adhesive resin cement (Maxcem elite chroma) on dentin. A total of 168 extracted human third molars were randomly divided into four main groups according to dentin pretreatment: no treatment, 10% polyacrylic acid, Optibond universal, and Scotchbond universal plus. Half of these were subjected to thermocycling (5000 cycles; 5–55 °C). Composite resin rods were bonded using the self-adhesive resin cement, and SBS was measured with a universal testing machine. Two-way ANOVA showed that dentin pretreatment and thermocycling significantly affected SBS, with significant interaction between factors (p < 0.001). The highest SBS was observed in the Optibond universal group (18.71 ± 0.43 MPa), while the lowest SBS occurred in the 10% polyacrylic acid-treated group after thermocycling (2.69 ± 0.39 MPa). Thermocycling significantly reduced SBS in all groups. These results indicate that pretreatment with a compatible universal adhesive improves bond durability, whereas 10% polyacrylic acid pretreatment adversely affects bonding performance. Full article

The extreme persistence of per- and polyfluoroalkyl substances (PFAS), exemplified by perfluorooctanoic acid (PFOA), demands remediation technologies that surpass conventional approaches. This study introduces a novel closed-loop adsorption–regeneration–distillation–plasma (ARDP) process designed for high-efficiency PFOA removal with low energy and chemical consumption. Comparative evaluation of anion-exchange resins identified D311 (macroporous methyl polyacrylate) as the optimal adsorbent. In batch experiments with an initial PFOA concentration of 100 mg/L, D311 achieved an adsorption capacity of ~20 mg/g, exhibited rapid kinetics, and achieved high regeneration efficiency (up to 100% under optimized conditions) via a methanol–NaCl solution. Distillation of the spent regenerant recovered approximately 80% of methanol while simultaneously concentrating PFOA for subsequent destruction, accomplished by utilizing waste heat from the plasma system, without the need for additional thermal energy input. Subsequent dielectric barrier discharge (DBD) plasma treatment of the residue achieved 100% PFOA degradation and up to 69% defluorination. The ARDP process proves to be a highly sustainable strategy, characterized by a low specific energy input (4.15 kWh/m³) and minimized secondary waste, making it a promising approach for practical PFAS remediation. Full article

This study investigates the substitution of fossil-based isocyanates with bio-based alternatives in polyurethane resin (PU) coatings and polyurethane dispersion (PUD) coatings, focusing on mechanical and thermal performance. The coatings were formulated using bio-based pentamethylene diisocyanate (PDI) and a range of fossil-based hexamethylene diisocyanate (HDI) trimers, combined with either a polyester polyol or a polyacrylate polyol. Differential-scanning calorimetry analysis revealed that PDI-based coatings exhibit higher reactivity during crosslinking, resulting in higher glass transition temperatures. Thermogravimetric analysis showed lower thermal stability compared to HDI-based polyurethanes, indicating increased rigidity but reduced thermal resilience. Mechanical testing of the coatings on wood showed superior microhardness, scratch resistance, and wear resistance for PDI-based coatings, particularly when combined with polyester polyols. Microscopic surface evaluation and roughness analysis confirmed smoother morphologies and lower crack densities in PDI-polyester coatings. Gloss and water contact angle measurements further demonstrated improved surface uniformity and hydrophobicity for PDI-based coatings. The FTIR spectroscopy validated the chemical integrity and more intense hydrogen bonding for PDI-based coatings. The post-wear spectra indicated chemical oxidation and surface rearrangements in PDI-based systems and mechanical degradation with chain scission for HDI-based coatings. Overall, the study highlights that bio-based PDI trimers can effectively replace fossil-based HDI trimers in PU and PUD coatings without compromising mechanical performance, especially when paired with polyester polyols. These findings support the development of more sustainable polyurethane coatings with enhanced durability and environmental compatibility. Full article

Powder coating, as a promising coating material, has attracted widespread attention due to its convenient construction and being a green option, promoting environmental protection. However, the existence of defects such as insufficient leveling and poor mechanical properties of the coating during the coating process limits the further expansion of its application fields. Therefore, for this article, powder coatings with high leveling performance were prepared by composite modification of nylon 12 (PA-12) resin with polyacrylates and ethylene-α-olefin copolymers (POE). The introduction of modified polyacrylates reduces the surface tension of nylon chains, enhancing melt flowability during curing and making the coating surface smooth. Furthermore, by introducing POE, the flexibility of the powder coating was improved, and its fracture elongation increased from 59% for pure PA-12 to a maximum of 234%. This study provides an effective method for the modification of nylon powder coatings and offers new insights into their use in high-performance coating applications. Full article

This study evaluated a biomimetic filler strategy for two-step universal dental adhesives by integrating amine-functionalized mesoporous silica nanoparticles (MSNs) loaded with polyacrylic acid-stabilized amorphous calcium phosphate (PA–ACP) into the primer phase. MSNs were synthesized and characterized by FTIR, N₂ sorption (BET), and HRTEM to confirm structural integrity and effective PA–ACP loading. Two commercial adhesives (G2 Bond and OptiBond eXTRa) were modified by incorporating different volumes fractions (10, 15, 20 vol%) of PA–ACP/MSN. Wettability (contact angle), microtensile bond strength (μTBS), and cytotoxicity (indirect MTT assay using human periodontal ligament fibroblasts, HPLFs) were assessed. The results demonstrated that incorporating up to 15 vol% PA–ACP/MSN maintained favorable wettability and bond strength, comparable to those of the unmodified controls. At 20 vol%, significant increases in contact angles and reductions in bond strength indicated impaired primer infiltration. Cytotoxicity testing confirmed high fibroblast viability (>70%) across all tested concentrations, verifying the biocompatibility of PA–ACP/MSN-filled primers. This work confirms the feasibility of a biomimetic adhesive design using PA–ACP/MSN in the primer phase without compromising immediate wettability and immediate μTBS up to 15 vol%. Remineralization is a potential capability that requires verification in future studies. Full article

In the field of water-based inks, the use of alkali-soluble resins (ASRs) as polymeric surfactants for synthesizing polyacrylate latexes has become a mainstream method. This study first designed and prepared crosslinkable ASRs with a diacetone acrylamide (DAAM) crosslinking monomer via emulsion polymerization. These ASRs were then employed as surfactants to synthesize self-crosslinking polyacrylate latexes through an in situ one-pot method, systematically investigating the influence of crosslinkable ASRs on the properties of the corresponding polyacrylate latexes. The research revealed that all prepared polyacrylate latexes exhibited a core–shell structure. With increasing DAAM content in the ASRs, the latex particle size gradually increased while the particle size distribution narrowed. All latexes demonstrated excellent stability, with absolute ζ-potential values exceeding 30 mV. The introduction of DAAM into ASRs significantly increased the glass transition temperature in the high-temperature region of the corresponding latex films, with the tensile strength reaching a maximum of 7.96 MPa. Moderate crosslinking in ASRs substantially improved the water resistance of latex films. Crosslinking degree tests indicated that latex films prepared through either single shell-layer crosslinking or single core-layer crosslinking showed relatively low crosslinking degrees, while only the dual core–shell crosslinking strategy could effectively enhance the film crosslinking degree. However, excessively crosslinked shell layers significantly hindered the crosslinking reaction of DAAM in the core layer, leading to reduced overall film crosslinking. Additionally, incorporating a certain number of DAAM crosslinking groups in ASRs was found to improve the adhesion of corresponding water-based inks on PE and BOPP substrates, with adhesion on BOPP substrates reaching up to 100%. Full article

This paper describes the synthesis of a viscosity-reducing agent using butyl acrylate (BA), ethyl methacrylate (EMA), acrylic acid (AA) and N-hydroxymethylacrylamide (N-MAM) monomers through emulsion polymerization. A series of viscosity-reducing agents were developed by incorporating varying amounts of glycidyl methacrylate (GMA) monomers. The reaction mechanism of epoxy acrylate viscosity reducer was analyzed by Fourier transform infrared spectroscopy (FTIR). Additionally, the particle size and Zeta potential were used to analyze the stability of the polymer and the difference in the polymer after adding GMA monomer. Thermogravimetric (TG) analysis indicated a significant improvement in the thermal stability of the resin due to GMA modification. The viscosity reduction test results demonstrated a substantial decrease in the viscosity of heavy oil, along with a notable increase in the viscosity reduction rate. The FTIR analysis results confirmed that GMA successfully introduced polyacrylate molecular chains. Furthermore, particle size and Zeta potential measurements showed that the average particle size of the emulsion increased from 132 nm to 187 nm, while the Zeta potential changed from −43 mV to −40 mV with the addition of 15% GMA. Compared with W0, the final thermal degradation temperature of W15 increased from 450 °C to 517 °C. When the GMA content reached 15 wt%, the maximum weight loss temperature increased by approximately 12 °C compared to the sample without GMA. Specifically, adding 8% W15 epoxy acrylate resulted in an 89% viscosity reduction rate for heavy oil, demonstrating an excellent viscosity reduction effect. This study successfully developed a novel epoxy acrylate viscosity reducer using a simple synthesis method, showcasing excellent stability, cost-effectiveness and remarkable viscosity reduction. Full article

Monitoring of real-time flow and defects in the vacuum-assisted resin infusion (VARI) process can provide important guidelines for full impregnation of dry reinforcement. A weak fiber Bragg grating array was employed to obtain quasi-distributed monitoring results in real-time. Sensitivity testing of different kinds of coated optical fiber sensors (OFs) was carried out first, and the polyacrylate-coated OF showed a greater wavelength-shift response than the polyimide-coated one. Then, two- and three-dimensional flow monitoring tests were carried out. During the resin-filling stage, three trends of strain curve were identpified in relation to the different placement setups of embedded OFs, the resin flow direction, and the different vacuum-bagging methods. The monitoring criteria were analyzed and the results were compared with the visual inspection, showing good agreement and indicating the ability of the fiber Bragg grating array. Finally, defects including dry spots and voids were introduced and reflected in the maximum changed strains of FBGs due to the smaller stress relaxation, indicating the potential to characterize the local flow state and permeabilities experimentally based on these quasi-distributed sensing methods. Full article

We developed a sustained-release transdermal drug delivery system (TDDS) containing simvastatin (SIM) and captopril (CAP) to treat hypertension and hyperlipidemia and overcome treatment drawbacks, including significant liver first-pass effects, low bioavailability, and the short half-life of SIM and CAP oral tablets. We used a transdermal diffusion meter to preselect the formula of the SIM-CAP TDDS. Based on in vitro permeation experiments, we optimized the formula of the SIM-CAP TDDS to include 24% SIM, 24% CAP, 34% polyvinyl alcohol (PVA), 16% oleic acid (OA)–azone, and 2% polyacrylic acid resin II. We evaluated the optimized SIM-CAP TDDS formula by its appearance, stability, stickiness, drug content, in vivo pharmacokinetics, and skin irritation tests. The results indicated that the patch had good stability and stickiness. The SIM and CAP contents were 5.02 ± 0.41 mg/cm² in the 1 cm² SIM-CAP TDDS. The pharmacokinetic results indicated that the system continuously released SIM and CAP for 24 h and significantly enhanced their bioavailability, with a higher area under the curve. The SIM-CAP TDDS exhibits a sustained-release effect with good characteristics and pharmacokinetics. And it is safe and has no irritating effects on the skin; therefore, it is an ideal formulation. Full article

Thermal frontal polymerization (FP) of acrylate monomers mixed with conventional peroxide initiators leads to significant bubble formation at the polymerizing front, limiting their practical applications. Redox initiators present a promising alternative to peroxide initiators, as they prevent the formation of gaseous byproducts during initiator decomposition and lower the front temperature, thereby enabling bubble-free FP. In this study, we investigate the FP of acrylate monomers of varying functionalities, including methyl methacrylate (MMA), 1,6-hexanediol diacrylate (HDDA), and trimethylolpropane triacrylate (TMPTA), using N,N-dimethylaniline/benzoyl peroxide (DMA/BPO) redox couple at room temperature and compare their front behavior, pot life, and bubble formation with those of same resin systems mixed with a conventional peroxide initiator, Luperox 231. The use of redox couples in FP of acrylates shows promise for rapid, energy-efficient manufacturing of polyacrylates and can enable new applications such as 3D printing and composite manufacturing. Full article

Photocatalysis is a promising technology for efficient sewage treatment, and designing a reactor with a stable loading technique is crucial for achieving long-term stability. However, there is a need to improve the current state of the art in both reactor design and loading techniques to ensure reliable and efficient performance. In this study, we propose an innovative solution by employing polydimethylsiloxane as a bonding layer on a substrate of 3D-printed polyacrylic resin. By means of mechanical extrusion, the active layer interacts with the bonding layer, ensuring a stable loading of the active layer onto the substrate. Simultaneously, 3D printing technology is utilized to construct a photocatalytic reactor resembling a “Kongming Lantern”, guaranteeing both high activity and durability. The reactor exhibited remarkable performance in degrading organic dyes and eliminating microbes and displayed a satisfactory purification effect on real water samples. Most significantly, it maintained its catalytic activity even after 50 weeks of cyclic degradation. This study contributes to the development of improved photocatalysis technologies for long-term sewage treatment applications. Full article

This paper presents studies on the influence of the chemical structure of (meth)acrylic monomers on the properties of powder coatings based on polyacrylate resins. For this purpose, a wide range of monomers were selected—2-hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), n-butyl acrylate (nBA), tert-butyl acrylate (tBA), dodecyl acrylate (DA), ethyl acrylate (EA) and benzyl acrylate (BAZ)—for the synthesis of the polyacrylate resin. The average molecular mass and molecular mass distribution of the synthesized resins were measured by gel permeation chromatography (GPC). The glass transition temperature (T_g) and viscosity of polyacrylate resins were determined by using differential scanning calorimetry (DSC) and a Brookfield viscometer. These parameters were necessary to obtain information about storage stability and behavior during the application of powder clear coatings. Additionally, DSC was also used to checked the course of the low-temperature curing reaction between the hydroxyl group contained in the polyacrylate resin and the blocked polyisocyanate group derived from a commercial agent such as Vestanat B 1358/100. The properties of the cured powder clear coatings were tested, such as: roughness, gloss, adhesion to the steel surface, hardness, cupping, scratch resistance, impact resistance and water contact angle. The best powder clear coating based on the polyacrylate resin L_HEMA/6MMA/0.5nBA/0.5DA was characterized as having good scratch resistance (550 g) and adhesion to the steel surface, a high water contact angle (93.53 deg.) and excellent cupping (13.38 mm). Moreover, its crosslinking density (CD) and its thermal stability was checked by using dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). Full article

Humic substances (HSs) present in water and wastewater cause fouling of anion exchange resins (AERs), which mainly results in reducing the ion exchange capacity (IEC). In this paper, an attempt was made to investigate fouling of two polystyrene and one polyacrylic AER using water from the Oder River, treated wastewater after the ultrafiltration process (UFTW) and digester reject water from sludge dewatering at the Janówek Wastewater Treatment Plant (WWTP) in Wrocław. HSs contained in digester reject water were characterised by the lowest aromaticity and molecular weights (MWs), the highest proportion of hydrophilic fraction and the highest amount of oxygenated functional groups. The Fourier-transform infrared (FTIR) analyses made it possible to identify chemical bonds characteristic of HSs and determine the mechanism of their retention on the surface of AER beads. The conducted experiments brought unexpected results, as the IEC increased with the amount of organic matter in the feed. Presumably, the humic substances accumulated on the beads and in the porosity of the anion exchangers themselves participated in the ion exchange process. Full article

To enhance the bioavailability and antihypertensive effect of the anti-depressant drug citalopram hydrobromide (CTH) we developed a sustained-release transdermal delivery system containing CTH. A transdermal diffusion meter was first used to determine the optimal formulation of the CTH transdermal drug delivery system (TDDS). Then, based on the determined formulation, a sustained-release patch was prepared; its physical characteristics, including quality, stickiness, and appearance, were evaluated, and its pharmacokinetics and irritation to the skin were evaluated by applying it to rabbits and rats. The optimal formulation of the CTH TDDS was 49.2% hydroxypropyl methyl cellulose K_100M, 32.8% polyvinylpyrrolidone K30, 16% oleic acid-azone, and 2% polyacrylic acid resin II. The system continuously released an effective dose of CTH for 24 h and significantly enhanced its bioavailability, with a higher area under the curve, good stability, and no skin irritation. The developed CTH TDDS possessed a sustained-release effect and good characteristics and pharmacokinetics; therefore, it has the potential for clinical application as an antidepressant. Full article