Abstract: A novel complex of polypyrrolidone, also known as nylon-4, and iodine is disclosed. The complex has biocidal properties exhibiting especially the fungicidal and bactericidal properties of free iodine but not its irritating and toxic properties. The complex may be formed with polypyrrolidone having any physical form, e.g. a powder, film, pulp, fiber or molded article. Bandage material made from nylon-4 fibers and complexed with iodine is a particularly useful form. Ointments and other compositions for topical application may also be made.

Abstract: A process and apparatus employing nylon 4 for the purification of water comprising the steps of contacting the water with iodine in a first treatment zone; nylon 4 complexed with iodine rather than elemental iodine is preferably used and is contacted by the water in the first treatment zone where it releases iodine at levels sufficient to purify the water. The treated and purified water is then contacted with nylon 4 in a second treatment zone where the iodine is removed from the water. The apparatus comprises a conduit having an inlet and an outlet, with a first treatment zone containing nylon 4 material complexed with iodine and a second downstream treatment zone containing nylon 4. The nylon 4 material used in both treatment zones can be in any form, preferably a form having a high surface area. A suitably restrained moistened fine powder may be used as may be textured or untextured, drawn or undrawn, staple fiber, knitted or non-woven fabrics or pulp (fibrils).

Abstract: A process for polymerizing 2-pyrrolidone to form a particulate material suitable for melt extrusion processes is disclosed. The process involves agitating to form particles at a critical point during the polymerization in which a friable gel exists. The gel is formed as a result of the addition of polymerization accelerators to the polymerization mixture but as the accelerated polymerization proceeds the gel soon hardens to a tough cake which can no longer be broken up by agitation. If the polymerizing mixture is agitated before the formation of the gel only very fine particles are formed.

Abstract: A method of drying quaternary ammonium compounds for use as additives in the anhydrous anionic polymerization of 2-pyrrolidone is disclosed.The method consists of dissolving or suspending the quaternary ammonium compound in 2-pyrrolidone and distilling over, under reduced pressure, a portion of the 2-pyrrolidone whereby the water is removed.

Abstract: A novel method of utilizing quaternary ammonium compounds to accelerate the polymerization of 2-pyrrolidone is disclosed. The method consists of dehydrating the hygroscopic quaternary ammonium compound by adding it to 2-pyrrolidone and distilling over, under vacuum, a portion of the pyrrolidone whereby the water is removed and then adding the residue to a conventional anhydrous polymerization mixture composed of an alkali metal salt of 2-pyrrolidone dissolved in 2-pyrrolidone and effecting polymerization by adding a polymerization initiator and heating the mixture to a temperature ranging from about room temperature to about 60.degree. C.

Abstract: There is disclosed a method of forming pure white polymers of 2-pyrrolidone when using SO.sub.2 as the activator. The method involves the use of the rubidium or cesium salt of 2-pyrrolidone as the alkaline catalyst in place of the sodium or potassium salt customarily used and which cause the formation of yellow polymer.

Abstract: A method of recovering and recycling quaternary ammonium accelerators for the polymerization of 2-pyrrolidone is disclosed. The method consists of removing the quaternary ammonium compound together with unpolymerized 2-pyrrolidone by washing the polymer with a solvent for both, such as water or methanol, neutralizing the solution immediately after washing and then removing the solvent at a sufficiently low temperature so that the quaternary ammonium compound is not decomposed.

Abstract: A process for forming polymers of 2-pyrrolidone in pellet form via bulk polymerization is disclosed. Polymerization accelerators are empolyed to markedly shorten the polymerization time thus making possible a compact continuous polymerization apparatus which produces pellets of high polymer content requiring no further polymerization. The pellets are formed by forcing the polymerizing mixture through small tubes to form rods of polymer which are then cut into short lengths.

Abstract: There is disclosed the use of certain quaternary ammonium sulfates and bisulfates as polymerization accelerators in the polymerization of 2-pyrrolidone employing alkali metal pyrrolidonates as primary catalysts together with CO.sub.2, SO.sub.2 or MoO.sub.3 as activators. Methods for recycling both the unchanged monomer and the accelerator are disclosed.The structural formula for the operable quaternary ammonium salts is: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are alkyl, aryl and aralkyl radicals, including mixtures thereof, and n is 1 or 2 depending on the valence of X, and X is a bisulfate or sulfate.In addition to accelerating the rate of polymerization these substances also act as color suppressors when SO.sub.2 is used as the activator. For this purpose X in the above formula may also be a halide. Less than 0.01 mol per mol of alkali metal pyrrolidonate is needed in this use.Cesium or rubidium pyrrolidonates are also disclosed as color suppressors when using SO.sub.2 as the activator.

Abstract: A method of forming white polymers of controlled molecular weight when polymerizing 2-pyrrolidone using an alkaline catalyst and sulfur dioxide as the chain initiator is disclosed. The temperature at which the polymerization is carried out is critical and is carefully controlled. The SO.sub.2 which must also be controlled within limits is diluted with an inert gas to diminish its activity and make it easier to measure the small amounts involved. The viscosity and thermal stability of the polymers formed are as good as or better than those formed when CO.sub.2 is used as the initiator.