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Ammonia is the most essential hydrogenated nitrogen composition that can cause problems when it enters the environment. One of the most important natural and synthetic adsorbents is hydrogels, which can reduce the economic costs of treating industrial effluents and minimize the concentration of ammonia in the drainage of sugarcane fields. In this study, carrageenan, which is a type of polysaccharide, and acrylic acid were used to prepare nanomagnetic hydrogels. Also, the effect of pH, concentration, and temperature on the amount of ammonia adsorption was analyzed by the spectrophotometer, and finally, the adsorption property of the hydrogel was analyzed by the scanning electron microscope (SEM). The results of scanning electron microscopy show that there are holes in the hydrogel surface that increase the rate of adsorption. Experimental data from the spectrophotometer show that the rate of ammonia adsorption increases by about 50% over 80 minutes as its concentration in the effluent increases. The inflation rate of these hydrogels was selected to be 991.52 (mg/g) under optimal conditions, and the nanomagnetic hydrogel adsorption capacity remained constant at a pH range of 4 to 9, while when the pH was below four or above 9, the capacity of adsorption shows a slight decrease. Adsorption by acrylic hydrogels is significant. There is an issue that by modifying the acrylic compounds in the production of the hydrogel, it is possible to absorb the heavy elements or colors in the best way and also to achieve high efficiency. Also, by increasing the amount of adsorbent nanomagnetic hydrogel up to 40 mg led to the adsorption of 89.16%, 32.50%, and 31.11% of ammonia in three pools of the test site, respectively. The results also show that the use of iron oxide nanoparticles in the hydrogel substrate has increased thermal stability by thermogravimetric analysis (TGA) which shows that at 650 degrees centigrade, kappa-carrageenan, hydrogels, and nanomagnetic hydrogels have a weight loss of 72.66%, 58.79%, and 52.39%, respectively. Studies have shown that the kappa-carrageenan-based hydrogel nanocomposite is more cost-effective, while it is more efficient at absorbing NH4+. Therefore, this adsorbent can be a promising material in terms of economic as well as its effectiveness in eliminating ammonia from sewage. Investigations were performed for ammonia desorption and the reusability of nanomagnetic hydrogels. Also, the rate of ammonia adsorption by nanomagnetic hydrogels after 6 cycles of recovery cycle using NaCl can be about 43% of the initial rate. All statistical studies were performed by Minitab software version 18 and considering p value = 0.05. [ABSTRACT FROM AUTHOR]

Objective. Infection control protocols in dentistry dictate that orthodontic acrylics have to be disinfected. No specific products for orthodontic acrylics are available. The objective of this study was to investigate the influence of chemical disinfectants on mechanical properties of orthodontic acrylics. Materials and Methods. 260 test specimens of two cold-curing orthodontic acrylics were manufactured. Three chemical disinfecting agents were tested: Impresept, D050 Instru-Gen, and Stammopur DR. Test specimens were stored in distilled water and divided into test groups. E-Modulus, flexural strength, macro hardness, micro hardness, average roughness, and colour change were measured. Results. Disinfection agents showed no significant influence on E-modulus. Values ranged from 1783.80 ± 163.80 MPa (Forestacryl colourless) to 2474.00 ± 135.00 MPa (Orthocryl green) after storage in distilled water. Disinfection agents performed no significant influence on flexural strength. Values ranged from 18.64±1.59 N/mm2 (Forestacryl colourless) to 25.64 ± 1.43 N/mm2 (Orthocryl green) after storage in distilled water. Orthocryl colourless showed a reduction of the macro hardness after disinfection (Stammopur DR (p≤0.001), D050 Instru-Gen (p≤0.037)). Disinfection of Orthocryl green with D050 Instru-Gen (p<0.001) and Forestacryl colourless with Impresept (p≤0.001) led to a reduction of macro hardness. Micro hardness of Orthocryl colourless altered significantly after disinfection with D050 Instru-Gen (p≤0.001). Micro hardness of Forestacryl colourless increased (Impresept (p≤0.039)) and decreased (Stammopur DR (p≤0.006) Instru-Gen (p≤0.001)) after disinfection. Average roughness did not change significantly (Orthocryl colourless). Forestacryl colourless performed a significant change after disinfection with Stammopur DR (p≤0.05). This is also true for the disinfection of Orthocryl green and Forestacryl pink with Instru-Gen (p≤0.05). Disinfection performed no significant influence on colour change. ΔE-values were in a range of 1 to 2. Conclusions. Some orthodontic acrylics disinfection caused significant changes of determined parameters. Changes were specific for the applied disinfectant and tested orthodontic acrylic. Further studies should verify the impact of long-term disinfection intervals. Thus, from manufacturers of orthodontic acrylics recommendations for appropriate disinfectants would be desirable. [ABSTRACT FROM AUTHOR]

ABSTRACT The monomers (5-ethenyl-1-azabicyclo [2.2.2] octan-2-yl)-quinolin-4-ylmethyl acrylate (EAOQMA) and (5-ethenyl-1-azabicyclo [2.2.2] octan-2-yl)-quinolin-4-ylmethyl methacrylate (EAOQMMA) were synthesized by reacting (5-ethenyl-1-azabicyclo octan-2-yl)-quinolin-4-ylmethanol [cinchonidine] with acryloylchloride and methacryloyl chloride, respectively, in the presence of triethylamine. The homopolymers were synthesized by the free radical polymerization in tetrahydrofuran at 70 ± 2°C in nitrogen atmosphere using 2,2′-azobisisobutyronitrile as an initiator. The monomers and homopolymers were characterized by UltraViolet (UV), Fourier transform infrared, Proton-Nuclear Magnetic Resonance (1H NMR), and Carbon-13 Nuclear Magnetic Resonance (13C NMR) spectroscopic techniques. The glass transition temperature ( Tg, °C) was determined by differential scanning calorimetry. The thermal stability of the poly(EAOQMMA) was performed by thermogravimetric analysis, which showed higher thermal stability of about 706°C than that of poly(EAOQMA). The antibacterial activity of monomers and polymers has been evaluated by determining the inhibitory zone diameters against Gram-positive bacteria ( Staphylococcus aureus) and Gram-negative bacteria ( Pseudomonas aeruginosa), in which cinchonidine acrylate and Cinchonidine methacrylate homopolymer showed better activity than their corresponding monomers. Surface morphology of the monomers and polymers were examined by Scanning Electron Microscope (SEM) analysis. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, acrylic-based conductive polymeric composite thin films were prepared by in situ chemical polymerization of pyrrole (Py) in the case of ammonium persulfate (APS) and iron(III) chloride (FeCl3). Composite thin films were produced by the solution casting method. The effect of polypyrrole (PPy) content and the type of oxidant on the morphological and dielectric properties were investigated. Temperature- and frequency-dependent dielectric properties were also studied in a frequency domain starting from 0.01 Hz to 10 MHz and in a temperature domain from 35 to 195°C. The results revealed that the dielectric constant and dielectric loss increased, whereas temperature and the highest dielectric values were obtained in the case of APS. The density of interconnected pores enwrapped with PPy under the surface improved the electrical/dielectric properties of the composite thin films. [ABSTRACT FROM AUTHOR]