Sorption and diffusion of aldehydes and ketones into elastomers

Abstract

The results of the sorption and diffusion of aldehydes and ketones into structurally different elastomers such as ethylene propylene diene terpolymer, styrene butadiene rubber, nitrile butadiene rubber, neoprene and natural rubber are described in the temperature interval of 25‐60°C. From these data, the Arrhenius parameters for the processes of diffusion and permeation are determined. The activation parameters for the diffusion of ketones range from 10.29 to 49.62 kJ/mol and for aldehydes, from 13.18 to 50.42 kJ/mol; these values fall in the range expected for rubbery polymers well above their glass transition temperatures. Transport data are affected by the nature of the interacting solvent molecule rather than its size and also by the structural variations of the elastomers. For all the solvents, the polymers remained intact; however, natural rubber in the presence of benzaldehyde showed degradative reactions at higher temperatures. Volumetric expansions of the elastomers have been measured from the dimensional response in the presence of aggressive solvents.

Adsorption of copper ions onto microwave stabilized heavy metal sludge

“…These results imply that the adsorption capacity and intensity of copper ions onto stabilized-sludge were enhanced at higher temperatures, indicating clearly that that equilibrium of adsorption is temperature-dependent. This effect may be due to the fact that at higher temperatures, an increase in movement of the solute to adsorbent [39]. It also can be explained by the fact that the total energy of sorbate was increased with increasing temperature.…”

Mechanical properties of polyurethane film exposed to solutions of nonoxynol‐9 surfactant and poly(ethylene glycol)

“…By using a two‐chamber diffusion cell, Saltzman27 measured similar diffusion coefficients for N9 (between 5 × 10 −10 and 4 × 10 −9 cm 2 /s) in a 100‐μm‐thick silicone elastomer. These values are higher than D for smaller molecules diffusing through elastomers (e.g., 60 × 10 −9 cm 2 /s for decane into Vibrathane B600 polyurethane membrane at 25°C53 or 70 × 10 −9 cm 2 /s for methyl salicylate into epichlorohydrin membrane at 25°C) 54. Increased thickness of the film because of swelling by N9 can affect the value of D ,55 but this was not the case here because the sample thickness was much less than the sample radius.…”

Sorption and diffusion of a brake fluid in EPDM elastomers

“…In order to investigate the transport mode, the sorption results have been analyzed using the empirical relationship [11][12] log…”

“…For values of n between 0.5 and 1.0, the transport follows anomalous-type pattern. [11][12] A typical plot of ln(Q t /Q ϱ ) Table III. The values of n for all the systems range between 0.55 and 0.60, indicating an anomalous-type transport and that these values were not affected by the temperature.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12] The solvent resistivity of these membranes is extremely important for applications including the construction of brake diaphragms. Thus, an understanding of the membrane transport properties-namely, sorption, diffusion, and permeation with respect to brake fluids-is essential in order to commercialize a brake system.…”