The present invention relates to a method for purifying polyalkylene carbonate. More specifically, a method for purifying polyalkylene carbonate is provided, which uses a multistage extraction column having the number of stages of at least 10 stages, using water for effectively removing by-products such as alkylene carbonate generated in a process for producing polyalkylene carbonate resin, thereby controlling the content of by-products to a certain level or less through a continuous operation, particularly, the extraction is performed at room temperature, thereby easily removing by-products in the resin without a high temperature volatilization.

The present disclosure relates to a method for preparing a polyalkylene carbonate. More specifically, provided is a method for preparing a polyalkylene carbonate in which after polymerization of polyalkylene carbonate, a mixture from which unreacted carbon dioxide and residual catalyst have been removed is charged into a stripper to remove the unreacted epoxide compound, and then heat-exchanged before removing the solvent to increase the temperature of the mixture stream to the maximum level, which is subjected to a heating step, following by a solvent removal step, whereby the amount of steam required in the heating step is reduced, side reactions due to unreacted epoxide compounds are prevented, and steam energy can be reduced in the solvent removal step.

The present invention relates to a method for selectively separating propylene carbonate by adding water to reaction products comprising a polyether carbonate polyol and propylene carbonate, which are generated from a polymerization reaction of propylene oxide and carbon dioxide under a double metal cyanide (DMC) catalyst, wherein an economical and effective separation of propylene carbonate can be achieved.

The present disclosure relates to a method for treating a solvent in wastewater generated in a polycarbonate production process. More specifically, the present disclosure relates to a method for treating a solvent in wastewater generated in a polycarbonate production process, which can easily recover a high purity solvent regardless of the concentration of the solvent by using a membrane distillation method to reuse it, and contribute to energy savings.

In an embodiment, a method of dewatering a wet polymer composition comprises introducing the wet polymer composition via a polymer feed location to a powder conveying section of an extruder; wherein the wet polymer composition comprises greater than or equal to 1 wt % of water based on the total weight of the wet polymer composition; venting the water through a conveying section vent to form a dry polymer composition; melt kneading the dry polymer composition in a melt kneading section of the extruder to form a polymer melt; conveying the polymer melt in a melt conveying section of the extruder; and adding an additive in one or both of the powder conveying section and the melt conveying section.

The purpose of the present invention is to provide an aromatic polycarbonate oligomer solid which has a markedly reduced amount of a low molecular weight component, has no or a markedly reduced amount of chlorine-containing compounds, has a high loose bulk density and is easy to handle. The purpose is met by an aromatic polycarbonate oligomer solid which includes a repeating unit represented by general formula (1), has a weight average molecular weight of 500 to 10000, has a low molecular weight component of less than or equal to 5.0 area % as measured by high performance liquid chromatography, and has a loose bulk density of greater than or equal to 0.20 g/cm.sup.3. ##STR00001##

The present invention provides a method for preparing a polycarbonate by removing a solvent from a polycarbonate polymerization solution without impairing the physical properties of the polycarbonate.

The present invention relates to a method for purifying polyalkylene carbonate. More specifically, a method for purifying polyalkylene carbonate is provided, which uses a multistage extraction column having the number of stages of at least 10 stages, using water for effectively removing by-products such as alkylene carbonate generated in a process for producing polyalkylene carbonate resin, thereby controlling the content of by-products to a certain level or less through a continuous operation, particularly, the extraction is performed at room temperature, thereby easily removing by-products in the resin without a high temperature volatilization.

A method of preparing a polyalkylene carbonate resin is provided. More particularly, a method of preparing a polyalkylene carbonate resin capable of preventing polymer degradation and improving physical properties and quality of a final resin product, in which, after polymerization of polyalkylene carbonate, by-products are removed by using a large amount of water to purify a reaction mixture, and in a subsequence process of removing a catalyst residue, a primary purification method is conducted by using a filter so that a content of the catalyst in the reaction mixture is less than 1% by weight, is provided.

The present disclosure relates to polythioaminals with applications as carriers or delivery vehicles for therapeutic agents or other small molecule cargo. Polythioaminal block copolymer coupled to a therapeutic agent is a polymer-therapeutic conjugate that exhibits higher stability and longer life time in aqueous environments. The polythioaminal block copolymer coupled to a therapeutic agent can be synthesized by reacting hexahydrotriazines with a hydrophobic block precursor, a hydrophilic block precursor, a particle stabilizing segment precursor, and a cargo, such as a therapeutic agent, in a one pot synthesis. The ease of synthesizing the resulting polythioaminal block copolymer coupled to the therapeutic agent while offering the extended stability and polymer life time in aqueous environments make the polythioaminal block copolymer particularly attractive for therapeutic carriers.