Benzene solubility parameter

When viscometric measurements of ECH homopolymer fractions were obtained in benzene, the nonperturbed dimensions and the steric hindrance parameter were calculated (24). Erom experimental data collected on polymer solubiUty in 39 solvents and intrinsic viscosity measurements in 19 solvents, Hansen (30) model parameters, 5 and 5 could be deterrnined (24). The notation 5 symbolizes the dispersion forces or nonpolar interactions 5 a representation of the sum of 8 (polar interactions) and 8 (hydrogen bonding interactions). The homopolymer is soluble in solvents that have solubility parameters 6 > 7.9, 6 > 5.5, and 0.2 < <5.0 (31). SolubiUty was also determined using a method (32) in which 8 represents the solubiUty parameter... 

Since polyethylene is a crystalline hydrocarbon polymer incapable of specific interaction and with a melting point of about 100°C, there are no solvents at room temperature. Low-density polymers will dissolve in benzene at about 60°C but the more crystalline high-density polymers only dissolve at temperatures some 20-30°C higher. Materials of similar solubility parameter and low molecular weight will, however, cause swelling, the more so in low-density polymers Table 10.5). 

Being a hydrocarbon with a solubility parameter of 18.6MPa - it is dissolved by a number of hydrocarbons with similar solubility parameters, such as benzene and toluene. The presence of a benzene ring results in polystyrene having greater reactivity than polyethylene. Characteristic reactions of a phenyl group such as chlorination, hydrogenation, nitration and sulphonation can all be performed with... 

The solubility parameters of PCL are 20.8 and 20.4 jl/2.cm"2 2 when calculated using the parameters of Fedors and Hoy, respectively (58). PCL is soluble in a number of solvents at room temperature, including THF, chloroform, methylene chloride, carbon tetrachlornie, benzene, toluene, cyclohexanone, dihydropyran, and 2-nitropropane. 

FIGURE 3 2 Solvent extraction efficiencies (EF) as functions of dielectric constants (D), solubility parameters (6), and polarity parameters (P and E -). Solvents studied silicon tetrachloride, carbon disulfide, n pentane. Freon 113, cyclopentane, n-hexane, carbon tetradiloride, diethylether, cyclohexane, isooctane, benzene (reference, EF 100), toluene, trichloroethylene, diethylamine, chloroform, triethylamine, methylene, chloride, tetra-hydrofuran, l,4 dioxane, pyridine, 2 propanol, acetone, ethanol, methanol, dimethyl sulfoxide, and water. Reprinted with permission from Grosjean. ... 

Figure 8.1. Relation of solubility parameters (solpars or Hildebrand 8 values) and carbon numbers in various homologous series of solvents. (4) Normal alkanes, (B) normal chloroalkanes, (C) methyl esters, (D) alkyl formates and acetates, (E) methyl ketones, (F) alkyl nitriles, ) normal alkanols, (H) alkyl benzenes, and (I) dialkyl phthalates.

PVAc has a specific gravity of 1.2 and an index of refraction of 1.47. It has a solubility parameter of 9.5 H and is soluble in liquids with similar solubility parameter values, such as benzene, chloroform, and acetone ... 

Polymers with solubility parameters differing from those of the solvent by at least 2.0 H, will not dissolve in the solvent at room temperature. Thus although unvulcanized natural rubber (NR), unvulcanized styrene-butadiene elastomer (SBR), unvulcanized butyl rubber, and EPDM dissolve in gasoline or benzene, the vulcanized (cross-linked) polymers are swollen but will not dissolve due to the presence of the crosslinks. 

The incorporation of polar groups in unvulcanized polymers reduces their solubility in benzene. Thus the copolymer of acrylonitrile and butadiene (NBR), polychlorobutadiene (Neoprene), and fluorinated EP (the copolymer of ethylene and propylene) are less soluble in benzene and lubricating oils than the previously cited elastomers. Likewise, silicones and phosphazene elastomers, as well as elastomeric polyfluorocarbons, are insoluble in many oils and aromatic hydrocarbons because of their extremely low solubility parameters (silicons 7-8 H polytetrafluoroethylene 6.2 benzene 9.2 toluene 8.9 pine oil P.6). 

Fig. 13. Effect of the solvent solubility parameter 8 on the linear coefficient of thermal expansion 3 (1) and modulus of elasticity E (2) of films of linear SBS thermoelastoplastics with 28.3% PS obtained from solutions. The solvent is indicated on the abscissa axis I — n-heptane, II — tetra-hydrofurane, III — benzene, IV — chlorobenzene 119)...

The differences in the master curves for log Ep(t) vs. log t obtained from Kraton 102 specimens cast from benzene, cyclohexane, and tetra-hydrofuran solutions may be caused by differences in the composition or the morphology of the phases. Beecher et al. (2) have emphasized the role of solvent in determining the phase structure of cast block copolymer films. At 25°C the solubility parameters for the polymers (3) and solvents (I) are Material Solubility Parameter... 

As shown in Figure 2, the rate of the heterogeneous copolymerization of styrene and maleic anhydride in benzene (8 = 9.2) is faster than the homogeneous copolymerization of these monomers in acetone (8 = 9.9). However, this rate decreases as the solubility parameter values of the solvents decrease in heterogeneous systems. Thus, the rate of copolymerization decreases progressively in xylene (8 = 8.8), cumene (8 = 8.5), methyl isobutyl ketone (8 = 8.4), and p-cymene (8 — 8.2). All of these rates were faster than those observed in homogeneous systems. The solubility parameter of the alternating styrene-maleic anhydride copolymer was 8 = 11.0. 

Comparable results were observed for the copolymerization of maleic anhydride and methyl methacrylate (8 = 10.8 for copolymer), methyl acrylate (8 = 10.7 for copolymer), and butyl methacrylate (8 = 10.7 for copolymer). However, the copolymers of maleic anhydride and stearyl methacrylate (8 = 10.3) and maleic anhydride and isobutyl methacrylate (8 = 10.4) have lower solubility parameter values, and hence, a slow homogeneous copolymerization was observed when these monomers were copolymerized with maleic anhydride in benzene. 

FIGURE 2.2 Regularsolutiontheory plotfor hydrocortisone solubility data. The curve represents thesolubility predicted by Equation 2.41 using data frorhexane, cyclohexane, carbon tetrachloride, toluene, and benzene to estimate the solubility parameter of hydrocortisone. (Data taken from Hagen, T. A. 1979. With permission of the author.)... 

Prior to this discovery, in 1954 Silberberg and Kuhn (62) were first to study the polymer-in-polymer emulsion containing ethylcellulose and polystyrene in a nonaqueous solvent, benzene. The mechanisms of polymer emulsification, demixing, and phase reversal were studied. Wetzel and Hocks discovery would then equate the pressure-sensitive adhesive to a polymer-polymer emulsion instead of a polymer-polymer suspension. Since the interface is liquid-liquid, the adhesion then becomes one type of R-R adhesion (35, 36). According to our previous discussion, diffusion is not operative unless both resin and rubber have an identical solubility parameter. The major interfacial interaction is physical adsorption, which, in turn, determines adhesion. Our previous work on the wettability of elastomers (37, 38) can help predict adhesion results. Detailed studies on the function of tackifiers have been made by Wetzel and Alexander (69), and by Hock (20, 21), and therefore the subject requires no further elaboration. 

Experimental vapor-liquid-equilibrium data for benzene(l)/n-heptane(2) system at 80°C (176°F) are given in Table 1.8. Calculate the vapor compositions in equilibrium with the corresponding liquid compositions, using the Scatchard-Hildebrand regular-solution model for the liquid-phase activity coefficient, and compare the calculated results with the experimentally determined composition. Ignore the nonideality in the vapor phase. Also calculate the solubility parameters for benzene and n-heptane using heat-of-vaporization data. 

Fig. 52. Correlation of C with the corresponding (5pol — 5 iq)2, where 5, is the observed solubility parameter of the polymer with respect to the class of liquids specified in Fig. 50 i.e. 9.5 for substituted benzenes, 8.4 for aliphatic esters, 9.1 for aliphatic ketones, and 7.3 for aliphatic ethers...

Fig. 53. Correlation of Log aliq with the solubility parameter, 5liq, reported for monosub-stituted benzenes, PhR, and calculated for C1(CH2) H liquids...

Benzene is termed a good solvent for polystyrene since Its solubility parameter (6=9.2H) Is within a previously established range of 1.8 for polystyrene (6=9.2H). When hexane (6=7.3H) was used at the same concentration, very little polymerization retardation was observed. The intrinsic viscosity and GPC elution times of the polymer resulting from the hexane modified emulsion Indicated it was substantially lower in molecular weight than the control. 

As shown In Figure 4, the rate of polymerization of styrene was retarded by good nonvlscous solvents such as benzene, cyclohexane, and octane whose solubility parameters (6) were within 1.5H of that of polystyrene at styrene to additive ratios of 3 to 1. The absolute rates were slightly Increased In poorer nonvlscous solvents such as heptane and hexane and were fastest In viscous nonsolvents such as dllsoctyl phthalate and Nujol. Rate studies Indicated a Rp dependency on [E] substantially greater than unity for the styrene emulsion systems modified with viscous poor solvents. 

The concept of asphaltenes is rooted in the solubility behavior of high-boiling hydrocarbonaceous materials in benzene and low-molecular-weight n-paraffin hydrocarbons. This behavior is a result of physical chemistry effects that are caused by a spectrum of chemical properties. This chapter has pointed out that by considering molecular weight and molecular polarity as separate properties of molecules, the solvent-precipitation behavior of materials derived from various carbonaceous sources can be understood. Future quantification of this approach probably can be achieved by developing a polarity scale based on solubility parameter. 

Ray SK, Sawant SB, Joshi JB, and Pangarkar VG. Development of new synthetic membranes for separation of benzene-cyclohexane mixtures by pervaporation A solubility parameter approach. Ind. Eng. Chem. Res. 1997 36(12) 5265-5276. 

Mandal S and Pangarkar VG. Development of copolymer membranes for pervaporative separation of methanol from methanol-benzene mixtures—a solubility parameter approach. Sep. Purif. Tech. 2003 30(2) 147-168. 

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