SynopsisThe development of porous polysulfone hollow fibers and the spinning process used are discussed. An analysis is given of the spinning parameters which determine fiber mechanical properties and permeability. Hollow fibers were prepared which display high modulus and high tensile strength. These fibers can withstand hydraulic pressures of more than 1000 psi. They can thus serve as supports for dense, ultrathin membrane coatings, useful in high-pressure reverse osmosis and ultrafiltration processes.

SynopsisSoluble chloromethylated polystyrene and its copolymers with vinylidene chloride as well as poly(pheny1 oxides) brominated in the side chains and in the ring were synthesized and characterized in detail by NMR. The halogenated polymers were phosphonylated with alkyl phosphites. Uncrosslinked polymers with pendent phosphonate groups were prepared in the presence of etheral solvents, which solvate the ionic intermediates of the Arbuzov reaction. These polyphosphonates are highly hygroscopic and are soluble in a variety of solvents. Their 2';s are in the range of 50-175OC. Their thermal behavior was analyzed on the basis of thermogravimetric measurements combined with mass-spectrometric analysis. Poly(styrene phosphonate) seems to be the most stable, and its thermal decomposition starts at -330°C. The polymeric phosphonates are compatible with an unusually large number of polymeric systems and seem to form "true" polymeric alloys with acetylcellulose.

No abstract

SynopsisThe morphology of porous polysulfone hollow fibers which were spun by the dry-wet spinning process is discussed. It was demonstrated that a relatively moderate quenching medium should be employed in the bore of the nascent fiber in order to produce an isotropic fiber free of macrovoids and intrusion cells. A rather delicate quantitative balance between the internal precipitant and the spinning solution has to be maintained, especially when low-viscosity polymeric solutions are employed. Scanning electron micrographs of fiber cross sections display highly porous, spongestructured walls which in some instances exhibit a rather dense interface skin. However, control of the extrusion/coagulation procedure allows the formation of skinned, porous skinned, and nonskinned fibers.