Papers by Keyword: Acrylonitrile

Abstract: Unreported peroxymonosulfate/mandelic acid as a redox pair initiation system has been used to graft copolymerizes acrylonitrile onto our previously prepared starch nanoparticle (SNPs) in aqueous medium under nitrogen atmosphere. Optimization of the grafting conditions was studied and the grafting parameters were expressed in terms of graft yield %, graft reaction efficiency % and homopolymer %. Fourier transformer infrared spectroscopy (FTIR), Scanning electron microscope (SEM) and thermal gravimetric analysis (TGA) techniques confirmed the synthesis of the precursor’s materials and the success of the grafting onto starch nanoparticle. The resultant copolymer was found to be more thermally stable and more resistance to biodegradability than the starch nanoparticle counterparts. Besides, the optimum conditions were obtained when using 1 g starch nanoparticle, 2 ml of AN (based on weight of substrate), 30 m mol/l potassium peroxymonosulphate, 8 m mol/l mandelic acid, 2 hours reaction time and 45°C of temperature.

Abstract: Comb-like poly(acrylonitrile-co-lauric acid) (PANLA) phase change materials with low phase change temperature were synthesized via mixed solvent precipitation polymerization where acrylonitrile (AN) and dodecyl acrylate (DA) were employed as monomers. Fourier transform infrared spectroscopy (FTIR) and ¹³C nuclear magnetic resonance spectroscopy (¹³C NMR) were used to characterize the chemical structure of the resultant PANLA. Differential scanning calorimetry (DSC) and thermogravimetry analyzer (TG) were adapted to evaluate the energy storage performance and thermal reliability of PANLA materials. Thermal analysis revealed that comb-like PANLA had a good energy storage performance and cyclic stability. The crystallization temperature of PANLA was around -8 °C with a crystallization enthalpy range of 3.77~41.30 J/g which was intended to apply in an environment with a relatively low temperature.

Abstract: A series of acrylonitrile (AN)-methacrylate (MA)-dimethyl maleate (DMM) terpolymers with different molar ratios were fabricated by emulsion polymerization. The feeding ratio agrees well with the composition of AN-MA-DMM terpolymer. With increasing the molar ratio of DMM in terpolymer, glass transition temperature (T_g) increases to higher temperature at first and then decreases. T_g drops to the lowest value-78.6 °C when the feeding ratio is 85/13/2 mol%. The melting temperature (T_m) of 85/11/4 AN-MA-DMM terpolymer is the lowest at-137.2 °C, while its resistant temperature (5 wt% weight loss, T_0.05) rises up to the highest value, -314.9 °C. DMM plays an important role in improving the melt flowability of PAN based copolymer. The cross sections of 85/14/1 AN-MA-DMM fiber are compact and the outer surfaces of the fiber are smooth. Tensile strength of AN-MA-DMM fiber is 3.4 cN/dtex.

Abstract: Natural rubber (NR) is one of the most important agriculture products of Thailand, which is an important material with unique and special characteristics used in wide range of applications such as mechanical properties, excellent strength, and elasticity. However, it is inferior in oil resistance due to the presence of hydrogen and carbon in its structure. This inherent drawback of NR has limited its application in industry. In order to expand the use of NR, this research is interested to improve the oil resistance of NR without loss of outstanding properties by grafting NR with acrylonitrile (AN) monomer to form the nano-matrix structure. The influences of the initial monomer concentration and initial initiator concentration were investigated. These effects on structure, mechanical properties and oil resistance properties were studied by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy, tensile machine, and swelling in toluene, respectively. It was found that the tensile strength and oil resistance properties of graft copolymerization of AN onto NR increased with increasing the percentage grafting efficiency of acrylonitrile monomer.

Abstract: The research reported in this paper aimed at exploring the advantages of using supercritical carbon dioxide (scCO₂) as an environmentally benign solvent and swelling agent for carrying out the grafting process of acrylonitrile (AN) onto polypropylene (PP) in the solid state by using benzoyl peroxide (BPO) as initiator in the reaction. In order to get a well graft ratio, the effects of various factors in this grafting reaction are investigated. Those factors included the reaction time, reaction temperature, monomer and initiator concentrations and the CO₂ pressure. IR was used to characterize the constituent of the graft polymer. Then anti-aging of the PP-g-AN was studied by UV-vis. Results showed that the scCO₂-assisted solid-state grafting process of AN onto PP did have some scientifically interesting and industrially relevant advantages over the melt process. Compare with virgin PP, the graft polymer have a better performance in anti-aging.

Abstract: Pure powdery high molecular weight polyacrylonitrile (HMW-PAN) copolymers were firstly synthesized by aqueous deposited polymerization (ADP) technique employing 2,2'-Azobis (isobutyramidine) dihydrochloride (AIBA) as initiator and itaconic acid (IA) as comonomer. Various PAN polymers were obtained through changing different polymerization parameters. It is indicated that with the increase of total monomer concentration, initiator concentration, reaction temperature and reaction time, polymerization conversions of PAN copolymers all increased. While the molecular weights become greater with the increase of total monomer concentration. With the increase of initiator concentration and reaction temperature (under higher reaction temperature region), the molecular weights decreased. However, the molecular weights only had very little decrease at the end of long extension of reaction time.

Abstract: In the present work, acrylonitrile removal from analogue wastewater was investigated using the combined Fe/C microelectrolysis–electro-Fenton. The optimization parameters such as ratio of Fe/C, pH value, the reaction time, the dose of H₂O₂, the voltage, and the stir time on the acrylonitrile removal efficiency were determined by measuring the percentage removal of Chemical Oxygen Demand (CODcr) in the acrylonitrile analogue wastewater. In the Microelectrolysis section, the ratio of Fe/C was 1:1, the pH value was 3.0, and reaction time was 1h. In the electrolyzing Fenton, the optimal conditions of process parameters were the dose of H₂O₂ oxidant (5ml/L), the voltage (2.0 V), electrochemical reaction time (40min), and stir time (20min).Under the optimal conditions, the percentage removal of was 69% in first section and about 35% in the second section. Also, the dose of oxidant (H₂O₂) decreased from 11ml/L to 5ml/L compared with the using single active carbon method.

Abstract: Electroreduction of acrylonitrile in ionic liquid BMimBF4 was studied to find a new green process for producing adiponitrile. Effects of cycling times, acrylonitrile concentration and water concentration were determined by cyclic voltammetry. One reduction peak of acrylonitrile was determined in first cycle and second reduction peak was determined after scanning 4th time. Currents of second reduction peak increased with adding scanning times. Peak current increased with increasing acrylonitrile concentration and water concentration. Peak potentials of voltammograms shifted to negative when increased acrylonitrile concentration, while it had reverse trend with increasing water concentration.

Abstract: Natural fibers possess many good characteristics, such as abundance, low cost, renewable, biodegradability and photo-degradability that made it a hot spot in exploiting current resources. Chemical modification is a new way to make efficient use of forestry and farming waste natural fiber resources. In this work, softwood fibers were modified by cyanoethylation with acrylonitrile. The influence of acrylonitrile dosage, reaction time, reaction temperature and the time immersed in sodium hydroxide solution with KSCN saturated on cyanoethylation were investigated. Fibers chemical structure and surface morphology before and after modification were characterized by FTIR and scanning electron microscope separately.

Abstract: In this paper ABS parts plus acrylonitrile monomer were prepared using melt blending method by twin-screw extruder, and the influence of soaking temperature, concentration of acrylonitrile monomer, ABS copolymer composition on the short-term migration of residual acrylonitrile monomer into pure water was studied, and the long-term migration behavior and diffusion coefficient were also further characterized.