Ways of preparing a partially crystalline polycarbonate powder are provided that include dissolving an amorphous polycarbonate in a polar aprotic solvent to form a first solution of solubilized polycarbonate at a first temperature. The first solution is then cooled to a second temperature, the second temperature being lower than the first temperature, where a portion of the solubilized polycarbonate precipitates from the first solution to form a second solution including the partially crystalline polycarbonate powder. Certain partially crystalline polycarbonate powders resulting from such methods are particularly useful in additive manufacturing processes, including powder bed fusion processes.

The present invention relates to a process for producing a polycarbonate from a diphenol or two or more different diphenols and a carbonyl halide by the interfacial process. It is a feature of the process according to the invention that it is carried out on the basis of a chlorohydrocarbon or a mixture of a mixture of two or more chlorohydrocarbons using an organic solvent. An organic solvent is also provided.

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 disclosure relates to an economical method of preparing a resin composition including a polyalkylene carbonate with improved thermal stability and processability. More specifically, the method of preparing a resin composition includes the steps of polymerizing carbon dioxide and an epoxide compound in the presence of a zinc-based catalyst and a solvent, recovering monomers, removing the catalyst and recovering raw materials, solution-blending with a thermostable resin to improve the thermal stability and processability, and removing the solvent and byproducts from the reaction mixture by using an agitated flash drum and an extrusion or kneader-type devolatilizer.

The present disclosure relates to an economical method of preparing a resin composition including a polyalkylene carbonate with improved thermal stability and processability. More specifically, the method of preparing a resin composition includes the steps of polymerizing carbon dioxide and an epoxide compound in the presence of a zinc-based catalyst and a solvent, recovering monomers, removing the catalyst and recovering raw materials, solution-blending with a thermostable resin to improve the thermal stability and processability, and removing the solvent and byproducts from the reaction mixture by using an agitated flash drum and an extrusion or kneader-type devolatilizer.

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 invention relates to a method for producing an oligocarbonate polyol devoid of aromatic groups and phenolic functions, comprising a step of polycondensation by transesterification of monomers (A1) and/or dimers (A2) and of diol monomers (B1) and/or of triol monomers (B2), in a particular molar ratio, in order to obtain an oligocarbonate polyol having a molar mass of less than 5000 g/mol and at least two hydroxyl-type chain ends, the monomer (A1) corresponding to the following formula: (A1) and the dimer (A2) corresponding to the following formula: (A2) as well as the oligocarbonate polyol that can be obtained by this method and the polycarbonate that can be obtained by reacting this oligocarbonate with a polyisocyanate.

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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.