The present invention relates to a method for preparing a stereoblock polylactide, comprising: a step of obtaining a first reaction mixture with a monomer conversion rate of 80 to 95% by adding a catalyst to a D-lactide and growing a PDLA chain; a step of obtaining a second reaction mixture with a monomer conversion rate of 80 to 95% by adding an L-lactide to the first reaction mixture and growing a racemic PDLLA chain at the end of the PDLA chain; and a step of further adding an L-lactide to the second reaction mixture and growing a PLLA chain at the end of the PDLLA chain through a polymerization reaction. The preparation method is capable of providing a more convenient synthesis by skipping a process of removing residual monomers in the middle of the reaction, and also of preventing multi-blocking and oligomerization of polymer chains due to a mixture of chains by gradually adding polymerizable monomers while controlling the monomer conversion rate in a one-port synthesis, thereby reducing chain transfer during the polymerization.

This disclosure relates to an aliphatic-aromatic copolyester of poly(butylene-co-adipate terephthalate) that is prepared from recycled polyethylene terephthalate in the presence of titanium catalyst and a phosphorous containing compound. The copolyester is contaminated with little or no ethylene glycol and/or isophthalic acid, which are artifacts of preparing the copolyester from recycled PET. Advantageously, because there is little or no contamination from ethylene glycol and/or isophthalic acid in the copolyester, there is essentially no depression in the material's melting temperature.

This disclosure relates to an aliphatic-aromatic copolyester of poly(butylene-co-adipate terephthalate) that is prepared from recycled polyethylene terephthalate in the presence of titanium catalyst and a phosphorous containing compound. The copolyester is contaminated with little or no ethylene glycol and/or isophthalic acid, which are artifacts of preparing the copolyester from recycled PET. Advantageously, because there is little or no contamination from ethylene glycol and/or isophthalic acid in the copolyester, there is essentially no depression in the material's melting temperature.

The present invention relates to a process for polymerising lactide into polylactic acid. The present invention also relates to reactor configuration for polymerising lactide into polylactic acid.

The present invention relates to a process for polymerising lactide into polylactic acid. The present invention also relates to reactor configuration for polymerising lactide into polylactic acid.

A hydroxyl-terminated polyester resin, a preparation method therefor and use thereof. The hydroxyl-terminated polyester resin is composed of the following raw materials in parts by mass: 25-50 parts of a diol, 40-70 parts of a dibasic acid, 0.1-2 parts of glycidyl tertcarbonate, 0.5-4 parts of a hydroxylation reagent, 0.08-0.3 parts of a catalyst and 0.2-0.5 parts of an antioxidant. The acid value of the polyester resin is 1-8 mgKOH/g, the hydroxyl value is 20-30 mgKOH/g, the melt viscosity at 200° C. is 9000-13000 mPa.Math.s, the reactivity at 180° C. is 410-520 s, the glass transition temperature is 53-59° C., and the softening point is 101-106° C.

The present invention relates to a process for preparing polyester polyols and also to the polyester polyols obtainable by the process.

A heat-resistant, bio-based polycarbonate ester prepared by melt polycondensation of 1,4:3,6-dianhydrohexitol and a carbonate or 1,4-cyclohexanedicarboxylate is disclosed. The heat-resistant, bio-based polycarbonate ester includes a repeat unit 1 of Formula 1, a repeat unit 2 of Formula 2, and a repeat unit 3 of Formula 3. The polycarbonate ester has excellent heat resistance, transparency, and processability. A method of producing the polycarbonate includes a step of melt polycondensation of 1,4:3,6-dianhydrohexitol and a carbonate or 1,4-cyclohexanedicarboxylate.

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A heat-resistant, bio-based polycarbonate ester prepared by melt polycondensation of 1,4:3,6-dianhydrohexitol and a carbonate or 1,4-cyclohexanedicarboxylate is disclosed. The heat-resistant, bio-based polycarbonate ester includes a repeat unit 1 of Formula 1, a repeat unit 2 of Formula 2, and a repeat unit 3 of Formula 3. The polycarbonate ester has excellent heat resistance, transparency, and processability. A method of producing the polycarbonate includes a step of melt polycondensation of 1,4:3,6-dianhydrohexitol and a carbonate or 1,4-cyclohexanedicarboxylate.

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A branched polyester suitable for use in solvent-free emulsification, the branched polyester having a first original weight average molecular weight before undergoing solvent-free emulsification and a second weight average molecular weight after undergoing solvent-free emulsification, wherein the branched polyester has a structure that limits degradation of the polyester during solvent-free emulsification to less than about 20 percent of the first original weight average molecular weight, wherein the branched polyester comprises a compound of the formula described.