Abstract The synthesis of sulfonated poly(phenylene oxide) polymer was investigated. The poly(phenylene oxide) was synthesized through oxidative coupling from 2,6‐dimethyl‐phenol with copper (I) chloride‐pyridine catalyst and sulfonated using chlorosulfonic acid. The effects of catalyst concentration, solvent, and other experimental variables on the kinetics of the polymerization of poly(phenylene oxide) and its subsequent sulfonation are reported in detail.
Abstract A description is given of the interfacing of an Apple II Plus “home” microcomputer to a Waters Model 200 Gel Permeation Chromatograph fitted with ultraviolet absorbance and differential refractive index detectors. Hardware design and the software required for data collection and data reduction are described. Flow charts are provided for the various data collection, analysis, and display programs used. Emphasis is placed on the flexibility that such a system offers to the computer programmer and the experimentalist.
Abstract The permeation and diffusion of helium, nitrogen, methane, ethane, and propane through γ‐irradiated polyethylene films were investigated. These studies were carried out with two objectives in mind: (1) to determine the effect of crosslinking by γ irradiation on permeability and diffusivity using the gas molecules as molecular probes; and (2) to study the plasticizing effects of the low hydrocarbons on the polyethylene film. The γ‐ray‐induced crosslinking efficiency of polyethylene was investigated in the following irradiation atmospheres: vacuum, acetylene, and nitrogen–acetylene mixtures. Results showed that irradiation in acetylene decreased the crosslinking efficiency while an acetylene–nitrogen atmosphere increased the efficiency compared to irradiation in vacuum. Both the permeation constants and the diffusion coefficients were found to decrease with increasing irradiation dose while the activation energies increased. The permeation constants of the organic gases through polyethylene increased with molecular diameter while the diffusion coefficients decreased. This increase in permeability was attributed to an increase in the solubility due to solubilization of the membrane by the penetrant. For example, the molecular diameter of propane is 4.397 Å compared with 2.807 Å for methane; however, propane permeated the polyethylene film at a rate twice that of methane. Nitrogen and methane have approximately the same molecular diameters—2.7085 and 2.807 Å, respectively—but owing to the plasticizing effect of methane, it permeated the film at a rate three times greater than that of nitrogen. It is interesting to note that the stronger the plasticizing ability of the penetrant, the greater the effect of the irradiation dose. The permeability of propane decreased by 40.7%, while the permeability of helium decreased by 6.4% after an irradiation dose of 50 Mrad.
Abstract The ionic crosslinking of poly(acrylic acid) for dialysis and reverse osmosis applications has been studied. A new dry technique has been developed that is faster than the wet technique reported in the previous paper to synthesize aluminum/poly(acrylic acid) membranes. It is based on casting a solution containing both the aluminum salt and the unneutralized poly(acrylic acid) (PAA) and subjecting the cast film to a heat treatment (curing step) to promote ionic crosslinking. Postcuring treatment in nonsolvents for PAA such as acetone induced structural modifications in the membrane. Membranes with optical clarity ranging from colorless and transparent to white and opaque were obtained and were characterized by their water and aluminum contents. Transport properties of these membranes were investigated and indicated a selective rejection of ionic solutes such as NaCl compared to organic solutes such as ethylene glycols. Typical results for reverse osmosis under static conditions at fluxes of 1250 g/hm 2 (0.75 U.S. gallons/ft 2 ‐day) gave rejections of 85% for a feed of 0.1% (by wt.) NaCl at 600 psi. Much lower rejection (28%) for ethylene glycol suggests the possible use of these membranes in the fractionation of mixtures of ionic and nonionic solutes by reverse osmosis.
Abstract Thin film composite membranes of sulfonated poly(phenylene oxide) (SPPO)–polysulfone (PS) (SPPO–PS) were prepared by coating the hydrogen or sodium form of SPPO onto various porous substrates such as polysulfone (PS). The effects of membrane preparation conditions and feed water variables on the salt rejection and production rates were investigated using reverse osmosis. Purification of the waste waters from the Alberta heavy oil fields for desalination and recycling use was carried out. Production rates and salt rejections for the various feeds were found to be in the range of 5–20 gfd (gallons/ft 2 day) and 80–99% respectively at 600 psig and 20°C, depending on the experimental conditions and membrane properties.
Abstract The anionic polymerization of 2‐pyrrolidone at 40°C via CO 2 /KOH and CO 2 /KOH/18‐Crown ether catalyst for membrane separation purposes was investigated in detail. The effects of reaction time, CO 2 quantity, and potassium hydroxide concentration including crown ether on yield and intrinsic viscosity were also studied. Under the reaction conditions of reaction temperature 40°C, reaction time 24 h, CO 2 quantity of 60 s at a constant flow rate of 3.5 L/min and 1.98 mol % Crown ether a maximum yield of 95.36% of nylon 4 polymer with intrinsic viscosity of 3.28 was obtained.
