Sorption of organic vapors by polystyrene

Activity coefficients of benzene, toluene, cyclohexane, carbon tetrachloride, chloroform, and dichloromethane in binary solutions with polystyrene at 23.5°C have been determined using a piezo-electric sorption apparatus. The investigated solvent concentration ranges were 15 to 39 wt % for benzene, 14 to 29 wt % for toluene, 15 to 28 wt % for cyclohexane, 26 to 38 wt % for carbon tetrachloride, 24 to 46 wt % for chloroform, and 21 to 41 wt % for dichloromethane. The polystyrene (weight-averaged) molecular weights were 1.1 × 10⁵ and 6.0 × 10⁵ g/gmole. The weight-fraction activity coefficients (Ω₁ = a₁/w₁) of cyclohexane, toluene, and carbon tetrachloride in polystyrene solutions determined in this work agree within experimental error with previously published values determined by measurement of vapor pressure lowering and vapor absorption by thin films. We find disagreement, at low solvent concentrations, between our results for benzene and chloroform and previously published results. We have analyzed our results using Flory's version of corresponding-states polymer solution theory. The theory can account, qualitatively, for the cyclohexane and carbon tetrachloride results. It cannot account for the toluene, benzene, dichloromethane, or chloroform results.     

Effects of poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] on the charge distributions of low‐density polyethylene/polystyrene blends

The effect of the triblock copolymer poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] (SEBS) on the formation of the space charge of immiscible low‐density polyethylene (LDPE)/polystyrene (PS) blends was investigated. Blends of 70/30 (wt %) LDPE/PS were prepared through melt blending in an internal mixer at a blend temperature of 220 °C. The amount of charge that accumulated in the 70% LDPE/30% PS blends decreased when the SEBS content increased up to 10 wt %. For compatibilized and uncompatibilized blends, no significant change in the degree of crystallinity of LDPE in the blends was observed, and so the effect of crystallization on the space charge distribution could be excluded. Morphological observations showed that the addition of SEBS resulted in a domain size reduction of the dispersed PS phase and better interfacial adhesion between the LDPE and PS phases. The location of SEBS at a domain interface enabled charges to migrate from one phase to the other via the domain interface and, therefore, resulted in a significant decrease in the amount of space charge for the LDPE/PS blends with SEBS. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2813–2820, 2004     

Tailoring of interface of polypropylene/polystyrene/carbon nanofibre composites by polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene

Mechanical and physical properties of polypropylene (PP)/polystyrene (PS) blend, PP/PS/polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) ternary blend and their composites with carbon nanofibers (CNF) were investigated. Composites of ternary blend exhibited superior properties compared to those of binary blends. Mechanical performance of nanocomposites was intimately related to their phase morphology. PP/PS/SEBS/0.1 wt% CNF hybrid composites exhibited excellent impact strength (Four-fold increase compared to PP/PS blend) and ductility (12-fold increase in elongation at break, with respect to PP/PS blend). Moreover, these composites displayed good tensile strength and modulus (15% increase in Young's modulus, compared to PP/PS/SEBS blend) and are suitable for various end-use applications including automobile applications. Although crystallinity of PP phase is decreased by the incorporation of CNF, thermal stability of the composites remained almost unaffected. Contact angle measurements revealed that ternary composites exhibited maximum hydrophobicity.     

Chromatographic investigations of adsorption of some aromatic compounds on aluminium oxide and silica gel from solutions

Summary Using adsorption TLC R_M values were measured for a number of aromatic compounds on aluminium oxide and silica gels having different specific surface areas, using the following binary mobile phases: benzene+toluene, benzene+carbon tetrachloride and chloroform+carbon tetrachloride. The results are graphically presented and compared with theoretically calculated values. Generally, a good agreement was found between the calculated and measured R_M values. The agreement is valid both when the R_M values were calculated using experimentally (indirectly) determined partition coefficients or when the coefficients are obtained with help of Ocik's equation [cf. Roczn. Chem.34, 745 (1960) and Chromatographia4, 516 (1971)]. One can assume that in the case of systems in which strong intermolecular interactions are absent, the statically determined partition coefficients of the compounds may be used for the calculation of their R_M values.     

Reversal of order of chemical shifts. Differential solvent effects in the hydrogen shifts of toluene,m-xylene and o-xylene as determined by 320 MHz tritium NMR spectroscopy

Chemical shifts for the aromatic tritons of toluene decrease in the order meta>para>ortho for pure toluene, but in the order meta>ortho>para for dilute solutions of toluene in carbon tetrachloride, chloroform, cyclohexane and dimethyl sulphoxide; m-xylene shifts are 5>4,6>2 in the pure state and 5>2>4,6 in carbon tetrachloride and dimethyl sulphoxide; o-xylene shifts are 4,5>3,6 in the pure state and reversed in carbon tetrachloride.     

The effect of polymer side chains on vapor sorption in polyacrylate and polymethacrylate solutions

The segment fraction Ψ₁ activity coefficients, a₁/Ψ₁, of solvents have been determined by the piezoelectric sorption method for 0.1 ≤ Ψ₁ ≤ 0.5 in binary solutions of chlorinated methanes [carbon tetrachloride (CCl₄), chloroform (CHCl₃), and dichloromethane (CH₂Cl₂)] with aromatic hydrocarbons (benzene and toluene) in poly(methyl methacrylate), poly(methyl acrylate), poly(ethyl methacrylate), and poly(n-butyl acrylate) at 23.5°C. The present results for toluene in PMMA agree with previously published values obtained by gas-liquid chromatography. For CCl₄ and the aromatic hydrocarbons, the polymer–solvent interaction parameter χ is positive and constant, while for the polar solvents (CHCl₃ and CH₂Cl₂), χ is negative and increases with increasing Ψ₁. The effect of the polymer side chains on vapor sorption in nonpolar and polar solvent systems is discussed in terms of the χ parameter.     

The reactions of diphenylcarbazide and diphenylcarbazone with cations : Part II. Extraction behaviour and spectra of the reagents

Extraction experiments in the carbon tetrachloride-water system for diphenylcarbazone above pH 7.5 give a value of (2.9 ± 0.3) ·10^-9 for the dissociation constant. At lower pH values the partition coefficients were found to be 7.5 for carbon tetrachloride-water and 39 for toluene-water in 0.1–1 M NaClO₄. The solubility of the carbazone in water is 3.8·IO^-4M in acid perchlorate medium.Spectra of diphenylcarbazone in water, toluene and carbon tetrachloride, of the anion in water and of diphenylformazane in toluene are compared. In the infra-red spectrum the C=O band was present in the carbazone, but not in the sodium salt.     

Excess volume of mixing of some polar and nonpolar liquids with propylene carbonate

The excess volume of mixing as a function of composition has been measured at 30°C and 40°C for mixtures of propylene carbonate with nitrobenzene, chlorobenzene, benzene, toluene, cyclohexane, dioxane, carbon tetrachloride, and chloroform. The highly polar nitrobenzene forms an ideal mixture with propylene carbonate. Chloroform, carbon tetrachloride, dioxane, chlorobenzene, benzene, and toluene give negative volume changes on mixing. In mixtures with cyclohexane,V _m ^E is positive at lower mole fractions of cyclohexane but becomes negative as the mole fraction of cyclohexane increases.     

Oxidation of polystyrene in solution

Polystyrene (PS) has been oxidized in carbon tetrachloride, chloroform, methylene chloride and cyclohexane under O₂ at atmospheric pressure using γ-initiation. Benzaldehyde, acetophenone and reductions in molecular weight were observed in all solvents. Yields of benzaldehyde and acetophenone were used to show that attack in chlorinated solvents is essentially random along the polymer chains and is predominantly by Cl^? radicals. Intramolecular propagation is much faster for attack on tertiary carbons than on secondary carbons. There are more neighboring hydroperoxide groups in PS oxidized in carbon tetrachloride and methylene chloride than in PS oxidized in chloroform, because, in chloroform, the solvent hydrogen is abstracted by polymer-based peroxyl radicals. For one set of conditions, about six intramolecular propagation steps took place in carbon tetrachloride and one in chloroform. At lower rates of initiation, the kinetic oxidation chains are longer and more intramolecular propagation occurs. HCl added in excess of that formed in these experiments decomposes hydroperoxide groups to give an autoaccelerating effect.Rates of scission were proportional to $\text{G}{}_{\mathrm{Cl?}}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, where G_Cl? is proportional to the rate of production of Cl? radicals. The alkoxyl radicals on polystyrene, produced in bimolecular interactions of peroxyl radicals, did not abstract hydrogen from the solvents, and thus appear to be very short-lived.The amount of oxidation of polystyrene in cyclohexane is much smaller than in chlorinated solvents. The analytical techniques used were too imprecise to allow meaningful comparison with the oxidations in chlorinated solvents.     

Combined effect of compatibilizer and carbon nanotubes on the morphology and electrical conductivity of PP/PS blend

In this work, maleic anhydride grafted styrene–ethylene–butadiene–styrene copolymer (SEBS‐g‐MA) and carbon nanotubes (CNTs) were introduced into the immiscible polypropylene/polystyrene (PP/PS) blend. Among the three polymer components, SEBS‐g‐MA has the strongest affinity to CNTs; thus, it exhibits dual effects to adjust the phase morphology of the blends and the dispersion state of CNTs in the blends. The experimental observations obtained from morphology characterizations using scanning electron microscope and transmission electron microscope confirm the selective localization of CNTs at the interface of the immiscible PP/PS blend. As a consequence, largely decreased percolation threshold is achieved when most of CNTs are selectively localized at the interface region between PP and PS. Copyright © 2014 John Wiley & Sons, Ltd.     

Effects of 60Co gamma rays on poly[bis(p-tolylamino)Phosphazene]

The behaviour of poly-[bis(p-tolylamino)phosphazene] under ⁶⁰Co gamma irradiation was investigated in chloroform, carbon tetrachloride, benzene, toluene and tetrahydrofuran. Viscosity, average molecular weights and spectral changes were used to follow the degradation. The degradation mechanism was interpreted in terms of a combined interaction of the polymer molecule with dissolved oxygen and radiolysis products of the solvent.     

Effect of solvent upon competitive liquid-liquid extraction of alkali metal cations by isomeric dibenzo-16-crown-5-oxyacetic acids

The selectivity and efficiency of competitive liquid-liquid extraction of alkali metal cations into organic solvents containingsym-(octyl)dibenzo-16-crown-5-oxyacetic acid (2) andsym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxyacetic acid (3) have been determined. Solvents examined include: dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, benzene, toluene,p-xylene, chlorobenzene, 1,2-dichlorobenzene, and 1,2,3,4-tetrahydronaphthalene. The Na⁺/K⁺ and Na⁺/Li⁺ extraction ratios are highest in chloroform. The extraction selectivity is found to correlate with the diluent parameter (DP) of the organic solvent.This paper is dedicated to the memory of the late Dr C. J. Pedersen.     

A Novel Synthesis of Isothiocyanates from Amines Using Triphenylphosphine/Carbon Tetrachloride

Abstract

Triethylammonium dithiocarbamates (RNHC (S) S.HNEt₃), prepared from aliphatic and/or aromatic amines, carbon disulfide and triethylamine, were treated with triphenylphosphine/carbon tetrachloride to give the corresponding isothiocyanates in good yields.     

Influence of extender oil composition on flowing property,thermal stability,and morphology of styrene‐b‐ethylene‐co‐butylene‐b‐styrene copolymer/polypropylene/oil blends

In this study, a series of styrene‐b‐ethylene‐co‐butylene‐b‐styrene copolymer (SEBS)/polypropylene (PP)/oil blends with different kinds of oil composition was developed through melt blending. The effect of oil with different composition and properties on its phase equilibrium and “redistribution” in multiphasic SEBS elastomer was systematically studied for the first time. Moreover, an integral influencing mechanism of oil composition on the structure and properties of SEBS/PP/oil blends was also put forward. The mineral oil was mainly distributed in ethylene/butylene (EB)/PP phase, which greatly enhanced the processing flowability of SEBS/PP/oil blends. With increasing oil C_N content, a redistribution of oil appeared and excess naphthenic oil (NO) entered the interphase of soft and hard phases. The dynamic mechanical thermal analysis (DMTA) analysis indicated that the polystyrene (PS) phase was plasticized, which also helped to improve the processing fluidity of blends. However, the plasticizing of physical cross‐linking point PS resulted in a decrease in mechanical strength and thermal stability. Small‐angle X‐ray scattering (SAXS) and transmission electron microscope (TEM) results showed that PS phase (45 nm to 55 nm) cylindrically distributed in EB/PP/oil matrix, the excess NO in the interphase enlarged the distance between PS phase and widen the escape channel for oil migration. At over 45% oil C_N content, the electron density difference between soft and hard phases reduced to the minimum, same as T_gPS, indicating a deeper plasticizing effect. The PS phase swelled and exhibited elastic behavior; thus, the force could be uniformly transferred between two phases. Importantly, a recover in strength and thermal stability was observed in O‐5 blend. This work significantly filled the gap of studies in oil‐extended thermoplastic elastomers (TPEs), exhibiting great theoretical guiding significance and application value.     

The Mechanism of the Polymerization of Styrene by Perchloric Acid

Abstract

The kinetics of the polymerization of styrene, initiated by anhydrous perchloric acid in carbon tetrachloride solution and in mixtures of methylene chloride and carbon tetrachloride, have been studied by NMR and GLC methods. In carbon tetrachloride the reaction is zeroth order. The kinetics, together with the known effects of dielectric constant and pressure on the reaction rate, suggest that the rate-determining step may be the formation of a carbonium perchlorate ion-pair, associated with neutral molecules of styrene.     

反气相色谱法测定离子液体1-己基-3-甲基咪唑三氟甲磺酸盐的热力学参数

采用反气相色谱法研究了343.15~373.15 K温度范围内离子液体1-己基-3-甲基咪唑三氟甲磺酸盐([HMIM]OTF)的热力学参数。根据18种探针溶剂的保留时间计算出探针溶剂与[HMIM]OTF之间的摩尔吸附焓、无限稀释的摩尔混合焓、摩尔蒸发焓、质量部分活度系数、Flory-Huggins相互作用参数及[HMIM]OTF的溶解度参数。结果表明,所选溶剂中正构烷烃、四氢呋喃、乙醚、环己烷和苯为[HMIM]OTF的不良溶剂;二氯甲烷、丙酮、氯仿、乙酸乙酯、四氯化碳、乙酸甲酯、甲苯和甲醇为[HMIM]OTF的良溶剂;运用外推法得到了室温(298.15 K)时[HMIM]OTF的溶解度参数为20.74 (J/cm³)^0.5。本研究为离子液体的应用及相关工作提供了参考。     

Photopolymerization of methyl methacrylate with the use of bromine as photoinitiator

Low concentrations of bromine (0.008–0.06M) were used to initiate photopolymerization of MMA in bulk and in diluted (near bulk) systems, the diluents or solvents used being benzene, toluene, dioxane, tetrahydrofuran, carbon tetrachloride, chloroform, methylene chloride, and methanol. Polymerization in bulk follows usual free-radical kinetics. Inert solvents (benzene, toluene) as well as the other solvents used enhance the rate of polymerization MMA even when used in the range of catalytic concentrations (0.04–0.4M). An initiation mechanism involving solvent molecules appears to be predominant in diluted systems.     

On the Reaction of Phosphorous Acid Esters with Nucleophiles in the Presence of Carbon Tetrachloride

Abstract

Esters of N-Phosphoryl phosphazenes are prepared by a modified Atherton-Todd reaction from di- and triesters of phosphorous acid, sodium azide, and carbon tetrachloride in high yields. The utilization of the two-component system trialkyl phosphite/ carbon tetrachloride for preparing phosphazenes, (RO)₃P[dbnd]NY (Y: PO(OR)₂, SO₂R, COR, CN), and dialkoxyphosphoryl compounds, (RO)₂P(O)X (X: NHR, NR₂, OPh, CN, F, NCO), is presented.