A method of manufacturing bulked continuous carpet filament from recycled polymer. In various embodiments, the method includes: (1) reducing recycled polymer material into polymer flakes; (2) cleansing the polymer flakes; (3) melting the flakes into a polymer melt; (4) removing water and contaminants from the polymer melt by dividing the polymer melt into a plurality of polymer streams and exposing those streams to pressures below 25 millibars or another predetermined pressure; (5) recombining the streams; and (6) using the resulting purified polymer to produce bulked continuous carpet filament.

A method is provided which reduces the transition time and/or the polymer waste in a continuous polymerization plant and/or process having a back-mixing reactor when polymer grades are changed from a first polymer grade to a second polymer grade. A monomer(s) and processing agent(s) are introduced to the reactor. The concentration of the processing agent(s) in a feed stream to the reactor is varied as a function of time from a first value associated with the first polymer grade to a final value associated with the second polymer grade. During the concentration variation one or more intermediate values of processing agent concentration are adjusted between at a first value, an intermediate value(s), and a final value. The intermediate values may be maintained for a time which is calculated on the basis of only residence time and steady-state correlations between input and output of the reactor and/or of the polymerization plant. The method is performed without performing dynamic modelling.

The present invention is directed methods of making absorbable poly(p-dioxanone) pellets by melt polymerization of p-dioxanone conducted in a single reactor with a temperature regulator by charging a melt reactor with a mixture of p-dioxanone (PDO) monomer, initiator, catalyst, and optionally a dye; melt polymerizing the mixture in the melt reactor with sufficient agitation of the mixture to allow complete mixing of the monomer and for sufficient time to form a PDO polymer product having an unreacted PDO monomer content of at least 65 mole percent; placing the PDO polymer product under a vacuum to remove at least portion of unreacted PDO; discharging the PDO polymer product from the melt reactor directly into an in-line, underwater pelletizer to produce undried PDO pellets, collecting the undried PDO pellets, and storing the collected PDO pellets in the freezer or a vacuum chamber prior to drying.

Provided herein are systems, and methods of using such systems, for producing acrylic acid from ethylene oxide and carbon monoxide on an industrial scale. The production system/production process has various unit operations, including, for example, a -propiolactone production system/production process configured to produce -propiolactone from ethylene oxide and carbon monoxide; a polypropiolactone production system/production process configured to produce polypropiolactone from -propiolactone; and a glacial acrylic acid production system/production process configured to produce acrylic acid with a high purity by thermolysis of polypropiolactone.

A method and an apparatus for solid-state polycondensation of polyesters, preferably polyethylene terephthalate and/or copolymers thereof. The method and apparatus are both characterized by a solid-state polycondensation being performed with polyester prepolymer particles in a reaction chamber in which an absolute pressure is in the range from 10 mbar to 200 mbar, and a process gas flow in the range of an R-value of 0.005 to 0.05. The polycondensation is carried out over a time of from 2 to 30 hours and at a temperature of from 180 C. to 5 below a crystalline melting point of the polyester prepolymer particles in order to achieve an intrinsic viscosity of from 0.70 to 0.95 dl/g. The R value is defined as a ratio of an hourly amount of process gas (in kg) flowing through the reaction space to an hourly amount of polymer (in kg) flowing through the reaction space: $R=\frac{m\left(\mathrm{gas}\right)\text{/}h}{m\left(\mathrm{polymer}\right)\text{/}h}.$

A method of manufacturing bulked continuous carpet filament from recycled polymer. In various embodiments, the method includes: (1) reducing recycled polymer material into polymer flakes; (2) cleansing the polymer flakes; (3) melting the flakes into a polymer melt; (4) removing water and contaminants from the polymer melt by dividing the polymer melt into a plurality of polymer streams and exposing those streams to pressures below 25 millibars or another predetermined pressure; (5) recombining the streams; and (6) using the resulting purified polymer to produce bulked continuous carpet filament.

Techniques regarding the synthesis of one or more polymers through one or more ring-opening polymerizations conducted within a flow reactor and facilitated by one or more anionic catalysts are provided. For example, one or more embodiments can comprise a method, which can comprise polymerizing, via a ring-opening polymerization within a flow reactor, a cyclic monomer in the presence of one or more anionic organocatalysts.

Techniques regarding the synthesis of polyesters and/or polycarbonates through one or more ring-opening polymerizations conducted within a flow reactor and facilitated by a urea anion catalyst and/or a thiourea catalyst are provided. For example, one or more embodiments can comprise a method, which can comprise polymerizing, via a ring-opening polymerization within a flow reactor, a cyclic monomer in the presence an organocatalyst comprising a urea anion.

The invention relates to the synthesis method of polyglycolic acid (PGA) obtained by removing the excessive water and monomer formed subsequent to condensation by means of an organic solvent and using azeotropic distillation method in the presence of a catalyst. The invention is a synthesis method of polyglycolic acid with high molecular weight and high solubility, characterized by comprising the steps of placing the glycolic acid in reaction medium with a catalyst; using hydrophilic organic solvents for removing the excessive water and monomer formed during condensation; mixing and boiling the mixture; stabilizing the amount of solvent in reaction medium and distilling the water off by means of Dean stark apparatus and/or a similar apparatus; refluxing the solid polymer obtained at the end of the reaction with ethyl acetate and removing the same from monomer residue and catalyst.

Disclosed is a process to produce a purified vapor comprising dialkyl-furan-2,5-dicarboxylate (DAFD). Furan-2,5-dicarboxylic acid (FDCA) and an alcohol in an esterification zone to generate a crude diester stream containing dialkyl furan dicarboxylate (DAFD), unreacted alcohol, 5-(alkoxycarbonyl)furan-2-carboxylic acid (ACFC), and alkyl furan-2-carboxylate (AFC). The esterification zone comprises at least one reactor that has been previously used in an DMT process.