Abstract: Improvements in color management for polypropylene fiber production in terms of permitting similar if not identical processing conditions for both colored and uncolored fiber production are provided. Generally, either separate polypropylene fiber manufacturing lines or different processing conditions on the same manufacturing line are required for the production of colored and non-colored polypropylene fibers. This coloring is, for example, done by using pigments that may have a nucleation effect on the PP polymer which affects fiber properties. Such an inefficient situation exists due to the physical properties of drawn polypropylene fibers during manufacture, particularly the different properties exhibited between fibers including color and fibers that are colorless.

Abstract: Unique thermoplastic monofilament fibers and yarns that exhibit heretofore unattained physical properties are provided. Such fibers are basically manufactured through the extrusion of thermoplastic resins that include a certain class of nucleating agent therein, and are able to be drawn at high ratios with such nucleating agents present, that the tenacity and modulus strength are much higher than any other previously produced thermoplastic fibers, particularly those that also simultaneously exhibit extremely low shrinkage rates. Thus, such fibers require the presence of certain compounds that quickly and effectively provide rigidity to the target thermoplastic (for example, polypropylene), particularly after heat-setting. Generally, these compounds include any structure that nucleates polymer crystals within the target thermoplastic after exposure to sufficient heat to melt the initial pelletized polymer and allowing such an oriented polymer to cool.

Abstract: A method for continuously separating polymer from a high pressure fluid stream comprises subjecting the high pressure fluid stream comprising polymer particles to a filter, wherein the filter segregates the high pressure fluid stream from the polymer particles; subjecting the polymer particles to a rotating device which transports the polymer particles away from the filter, wherein the polymer particles are exposed to thermal conditions sufficient to melt the polymer particles and form a seal surrounding at least a portion of the rotating device; and separating the molten polymer from the rotating device. The method is carried out such that the separation of polymer from the high pressure fluid stream occurs under steady-state.

Abstract: A method of depolymerizing a polymer comprises contacting a polymer with a fluid comprising carbon dioxide and at least one component, wherein the fluid plasticizes the polymer and facilitates penetration of the component into the polymer to depolymerize the polymer and form oligomeric units, monomeric units, or combinations thereof.

Abstract: A method of producing a foamed material comprises contacting a material with a fluid mixture comprising carbon dioxide and a surfactant, wherein the surfactant facilitates the dissolution of the carbon dioxide into the material and then foam the material in the fluid mixture.