Papers by Keyword: Styrene

Abstract: pH-switchable chain transfer agent 1-cyano-1-methylethyl (phenyl)(pyridin-4-yl)-carbamodithioate (CMPC) was synthesized and reversible addition-fragmentation chain-transfer (RAFT) polymerization of styrene in presence of CMPC was studied. It was shown that presence of CMPC affects molar mass distribution and kinetic features and realizes supposed mechanism of RAFT polymerization. Different effect of CMPC on polymerization of styrene in presence of protic acids was studied.

Abstract: The paper describes the synthesis of three new copolymers based on styrene and α-methylstyrene derivatives by radical emulsion copolymerization in an aqueous medium in the presence of an ammonium persulfate initiator and potassium stearate emulsifier. In early study, it was found that copolymers based on methoxy derivatives of styrene have the advanced dielectric properties, as compared to polystyrene and a copolymer of styrene and α-methylstyrene. In addition, the latest scientific literature provides data on the biological activity of styrene copolymers. Thus, the synthesis and study of the properties of new copolymers based on styrene and α-methylstyrene creates a prospect for establishing materials with a unique set of properties differing from their previously studied analogues. The structure of synthesized copolymers is confirmed by IR spectroscopy. Along with this, the paper provides the curves of thermogravimetric analysis, data on dielectric constant and tangent of a dielectric loss angle. A hemolytic effect of copolymers is determined, which indicates biocompatibility and further research perspectives towards their suitability for medical use. A copolymer of sodium 4-styrenesulfonate and α-methylstyrene (the molar ratio of starting monomers is 7:3) is soluble in an aqueous medium, which makes it of higher priority in terms of further study into biological activity.

Abstract: Polystyrene is a type of plastic that is widely used in daily life. It is applied for decoration, food packaging, and electronic packaging process. However, the use of polystyrene has become a problem for the environments because its properties are difficult to be degraded by nature. Pyrolysis method can be regarded as one of the environmentally friendly methods for recycling polystyrene waste. This research aims to investigate the effect of bentonite and natural zeolite catalyst on the pyrolysis of polystyrene. The experiment was carried out in a batch process. The pyrolysis process consists of a cylindrical reactor with electrical heater, a condenser, and a liquid product container. About 100 grams of polystyrene material was pyrolysis per batch. Catalysts used in the variation of 0%, 10%, 15%, 20%, and 25% of polystyrene. The liquid product was collected in 60 minutes and weighed. The composition of the liquid product was determined by gas chromatography. Polystyrene pyrolysis utilizes bentonite and natural zeolite as the catalyst. It produces benzene, toluene, ethylbenzene, styrene, and isopropyl benzene as the liquid product, and polystyrene residue as a solid product. Among the catalyst studied, bentonite is found to be the most efficient and increase the styrene selectivity (30.28 wt%) significantly at a reaction temperature of 400°C in comparison to the natural zeolite catalyst.

Abstract: The Abundant production of Palm Fatty Acid Distillate (PFAD) can be utilized to make high value product, such as alkyd resins for coating materials. In this research, PFAD was reacted with glycerol and phthalic anhydride at various composition and temperature for 4-5 hours, employing one-step and two-step methods. The alkyd resin product was analyzed its acid value, iodine number, viscosity of 5% solution in xylene, and curing possibility with styrene monomer. The results showed that reaction temperature at 180° - 220°C influenced the acid value, but not significant for iodine number, and had no effect to molecular weight of alkyd resin product. Phthalic anhydride had more effect upon acid number than PFAD. Iodine number of the alkyd resin product was generally low, which indicated that this alkyd resin could not be used as drying oil. All alkyd resins produced either by one and two steps could only harden with 20% alkyd resin - 80% styrene using MEKP initiator. Viscosity of 5% alkyd resin solution in xylene was around 11-14 cp, independent of composition and reaction temperature.

Abstract: One of the coal combustion ashes is coal bottom ash. Low rank coal bottom ash can act as TiO₂ catalyst’s support which was calcined at varying temperature, has been created. The low rank coal bottom ash model was collected from low rank coal which burned in muffle furnace at 800 °C for 2 h. Subsequently, the low rank coal bottom ash was impregnated with titanium (IV) isopropoxide (Ti (PrO)₄) 500 μmol, and then calcined at variation temperature of 300, 400, 500, 600 and 700 °C. The modified physiochemical property of catalysts were determined UV-vis spectroscopy, N₂ adsorption-desorption and hydrophobicity test. The performances of the catalysts were tested for styrene oxidation with H₂O₂ aqueous as oxidant. It is found that the low rank coal bottom ash was as good catalyst support, whereby TiO₂ supported low rank coal bottom ash which calcined at 400 °C possessed the best catalytic activity with styrene conversion 45% and selectivity 87%.

Abstract: In this work we represent the results for the development of proton conductive membranes by radiochemical modification of thin PVDF films with their subsequent sulfonation. Radiation source were ⁴He ions with energy of 27 MeV produced by cyclotron R-7M the FTI TPU. The results of IR-spectroscopy, gravimetric analysis and microscopy are represented to evaluate changes in membranes properties. It was shown that the deepness of modificated gel can be controlled by radiation.

Abstract: Microporous aluminophosphate (AlPO-5) and titanium aluminophosphate (TAPO-5) molecular sieves, which are zeolite-like materials have been synthesized by direct hydrothermal method using two different templates; triethylamine (TEA) as organic base and tetraethylammonium hydroxide (TEAOH) as alkali base. XRD patterns confirmed that the TAPO-5 catalysts are identical with AFI structure but the crystallinity of the catalysts had decreased after the incorporation of titanium into the framework. Besides that, characterization of TAPO-5 catalysts using DRUV-Vis confirmed the coordination of titanium species and this evidenced also supported by the result ²⁷Al MAS NMR. Catalytic performance of the TAPO-5 catalysts was tested in the oxidation of styrene to produce benzaldehyde and phenylacetaldehyde in the presence of hydrogen peroxide as oxidant. TAPO-5 catalysts showed higher activity in styrene oxidation compared to AlPO-5. Keywords : zeolite; aluminophosphate; titanium; organic template; styrene

Abstract: In this paper, a mixed microbial population biotrickling filter (BTF) was investigated for styrene removal with two different packings at different empty bed residence times and gas-liquid ratio(GLR). The two biotrickling filters inoculated with a Pyrocarbon-sawdust and ceramic-raschig-rings-sawdust mixed packings were filled respectively in two identical laboratory-scale biotrickling filters which were operated in parallel. The results showed that the BTF filling with pyrocarbon-sawdust packings had higher rate of bio-film formation and removal efficiency of styrene than that of ceramic-raschig-rings-sawdust packings. When an inlet gas concentration of 50 to 450 mg/m³, an Empty Bed Residence Time (EBRT) of 21.6 to 43.2 s, and a gas-liquid ratio (GLR) of 110.7 to 55.3, a maximum styrene removal load is up to 153.1 g/(m³·h). During shock-load experiments with shutdown, the styrene removal efficiency of the BTF could gradually reach 92 % to 100 % by 14 h.

Abstract: The experimental study of the kinetics of styrene monomer accumulation in polyvinylidene fluoride films with radiation-chemical grafting of styrene monomer is presented. It is proved that the degree of grafting depends on the absorbed dose of helium ions, temperature and composition of the grafting solution.

Abstract: Styrene was selectively oxidized to styrene oxide with macrocylic amido Mn (II) complex as catalyst and tert-Butyl hydroperoxide (TBHP) as oxidant. The effects of reaction temperature, reaction time, solvents, amount of catalyst and oxidant on the conversion and selectivity of styrene epoxidation were investigated. The optimized conditions were achieved by molar ratio of n (catalyst) :n (styrene)=1% in acetonitrile solvent at 75 °C in 1.5 h. Under optimum reaction conditions, reaction conversion of 92.6% and selectivity of 86.9 % were obtained.