Antioxidants are used in propellant formulation to prevent oxidation and increase their lifespan. Oxidation Induction Time (OIT) test is one of the best methods to analysis the performance of antioxidants. This test determined the resistance of the polymer against oxidation. In this work, the performance of the 2,2'-methylene bis-(4-methyl-6-tert-buthyl phenol)(AO.2246), N-isopropyl-N'-phenyl-1(IPPD),4-phenylene di amine, N-methyl aniline, Tris(nonyl phenyl)phosphite (TNPP), Irganox 415 and Synergic effect (use primary and secondary antioxidant) in binder system based on Hydroxyl terminated polybutadiene( HTPB) were investigated through the OIT analysis. The obtained results show that the best antioxidant performance in the binder system based on HTPB is related to the simultaneous use of the primary antioxidant (AO.2246) and secondary (TNPP) types with a ratio of 2:1.

2,2'-Arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives are important biologically active compounds, which can be evaluated as tyrosinase inhibitors. They are important intermediates in the synthesis of xanthenes that are known as an important class of heterocyclic compounds with biological and therapeutic properties. Several methods have been employed for the preparation of 2,2'-Arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives, including the use of molecular iodine, ultrasonic and microwave irradiation. Some of these methods however, involve harsh reaction conditions. Therefore, further improvement toward milder reaction conditions and higher yields is required. In recent years, the advance of electro-synthesis have attracted organic chemists for having advantages such as short reaction time, high yields with easy work-up and do not require the use of harsh conditions such as high temperature and expensive reagents. In this study, we report a convenient and facile synthesis of 2,2'-Arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) based on electro-catalytic transformation of aldehyde and dimedone in an undivided cell containing an iron electrode as the cathode and a Pt electrode as the anode at a constant current in the presence of potassium bromide as an electrolyte at room temperature.

Boric acid aqueous solution system as an efficient catalytic system was applied for the reaction of phenyl hydrazine, ethyl acetoacetate and aryl aldehydes to prepare bis(pyrazolyl)methanes. By the reaction of Boric acid with water, H+ was generated and catalyzed the reaction under green and mild condition. In this paper, the synthesis of bis(pyrazolyl)methanes including 4,4´-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s was reported by tandem Knoevenagel–Michael reaction of phenyl hydrazine, ethyl acetoacetate and aryl aldehydes in the presence of boric acid aqueous solution system, at 70 °C with high yields and short reaction times. Boric acid aqueous solution system as an efficient catalytic system was applied for the reaction of phenyl hydrazine, ethyl acetoacetate and aryl aldehydes to prepare bis(pyrazolyl)methanes. By the reaction of Boric acid with water, H+ was generated and catalyzed the reaction under green and mild condition. In this paper, the synthesis of bis(pyrazolyl)methanes including 4,4´-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s was reported by tandem Knoevenagel–Michael reaction of phenyl hydrazine, ethyl acetoacetate and aryl aldehydes in the presence of boric acid aqueous solution system, at 70 °C with high yields and short reaction times.

An efficient and eco-friendly method is introduced for the synthesis of 4,4'-(arylmethylene)-bis-(1H-pyrazol-5-ols) by the condensation reaction of two equivalents of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one with various aromatic aldehydes, catalyzed by the boehmite nanoparticles (BNPs). This heterogeneous catalyst was recycled and used in four runs for the reaction between benzaldehyde and 3-methyl-l-phenyl-5-pyrazolone without any loss of its catalytic activity.

In this paper, the rheological behavior of SiC suspensions, fabricated via gel-casting method, and the influence of this behavior on the mechanical properties of the sintered samples were studied. To prepare castable and stable SiC suspensions, the rheological behaviour of the suspensions was characterized and optimized. To this aim tetramethylammonium hydroxide as dispersant, acrylamide as monomer, methylenebisacrylamide as cross linker, ammonium persulfate as initiator and tetramethylethylenediamine as catalyst were used. The results indicated that for obtaining stable SiC suspensions with suitable viscosity, 0.4 wt% dispersant of tetramethylammonium hydroxide, the pH of 10.5 and mixing time of 24 h were required. It should be noted that this suspension was electrosterically stable and the presence of the monomer acrylamide decreased the viscosity. The results showed that in the optimal ratio of methylenebisacrylamide cross linker to acrylamide monomer the highest strength was obtained. The flexural strength of the gel cast bodies was 231 MPa.

The direct polycondensation reactions of diacid, 5-(3-acetoxynaphthoylamino)isophthalic acid with various aromatic and aliphatic diisocyanates such as 4,4'-methylene bis(4-phenylisocyanate), toluylene-2,4-diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate were carried out under microwave irradiation conditions. In order to compare this method with classical heating, the polymerization reactions were also performed under solution polycondensation conditions. The polymerization reactions occurred rapidly under microwave conditions and produced a series of polyamides containing pendent acetoxynaphthalamide group, with good yields and moderate inherent viscosities of 0.26-0.45 dL/g. The comparable yields and higher inherent viscosities were obtained by microwave irradiation versus thermal heating with substantial reduction in reaction time.

Poly lactic acid (PLA) films were prepared using different mass% of a network polymer by casting method and water vapor and oxygen permeability of prepared films were investigated. The network polymer was synthesized from 2-acrylamido-2-methylpropanesulfonic acid and N,N′-methylenebisacrylamide by radical polymerization and its structure was confirmed by fourier transform infrared spectroscopy (FTIR). The result of X-ray analysis was indicated that the network polymer structure had been a desirable interaction with poly lactic acid. By increase network polymer content to PLA, the water vapor permeability and oxygen transmission rate have decreased. The water vapor permeability was decreased from 0.243 ± 0.012 g/m2.24h for neat PLA to 0.235 ± 0.01 and 0.229 ± 0.013 g/m2.24h for the PLA films containing 2 and 6 mass% of network polymer, respectively.

Silica vanadic acid (oxo-vanadium has been supported on silica) with Lewis and Bronsted acid site is introduced as an efficient, reusable, and heterogeneous catalyst for tandem Knoevenagel–Michael reaction of two equivalents of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one with various aromatic aldehydes for the synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ol)s at room temperature. The present methodology offers several advantages over existing methodologies, such as excellent yields, short reaction time, simple procedure, easy work-up, mild reaction conditions, and synthesis of wide range of products. This procedure gave the products in excellent yields within very short reaction times over other vanadium(V) compounds. Also this catalyst can be reused six times without appreciable loss of its catalytic activity.

In this study, the synthesis of a magnetic multi walled carbon nanotubes nanocomposite hydrogel (MMWCNT/Hydrogel) are investigated.(2-dimethylaminoethyl) methacrylate monomers were grafted onto the sodium alginate backbone via initiation by ammonium persulfate (APS), and at the same time, the crosslinking were occurred by using N,N'-methylenebis(acrylamide) (MBA). Factors affecting the water swelling during the hydrogel synthesis, including monomer concentration, MBA concentration and APS concentration were systematically optimized. Swelling capacity was measured at various temperatures, pH values and salt concentrations, and the dependence of swelling properties of the hydrogel nanocomposite on these factors was well demonstrated. The synthesized samples were fully characterized using Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy analysis (FESEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM).

In this study, a hydrogel based on graft copolymer of itaconic acid (IA) onto chitosan (CS) was synthesized. For this purpose, the reaction was performed in nitrogen atmosphere and ammonium persulfate (APS) was used as an initiator and N,N-methylene bisacrylamide (MBA) as a crosslinking agent. In order to improve the water absorption, the effect of silver, silicon, and titanium oxide nanoparticles on hydrogel swelling was studied. Fourier transform infrared (FTIR) spectroscopy was used to confirm the structure and field emission scanning electron microscope (FESEM) used to study the morphology of the compounds. The presence of nanoparticles in the synthesized nanocomposites was confirmed by EDAX analysis. The results of water absorption showed that the synthesized hydrogel with 0.4 g MBA has the highest water absorption (19.7 g / g) and the presence of nanoparticles in the hydrogel structure increases the water absorption and SiO2 has the greatest effect so that the water absorption of nanocomposites containing silicon, titanium oxide and silver was obtained as 29.18, 26.92 and 23.47 g/g, respectively.