A process for the ring-opening copolymerisation of epoxides with carbon dioxide for the preparation of a polycarbonate is described. Also described are catalysts useful in the aforementioned process. The heterobimetallic catalysts present a number of advantages over catalysts that have conventionally been used for this process.

The present invention relates to a kind of organic metal-free catalysts containing both electrophilic and nucleophilic dual-functions, preparation methods of making the same, and uses thereof. The organic metal-free catalysts in the present invention have the chemical structure shown in formula (I): ##STR00001##
Compared with the metal-free organic polymerization catalytic systems that have been reported before, the organic metal-free catalysts in this invention have the combined advantages of simple preparation, high reactivity, easy operation, low cost, wide applicability, easy for industrial production.

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.

An aliphatic copolycarbonate and a preparation method thereof are disclosed. The aliphatic copolycarbonate contains a structural unit represented by formula (1) and a structural unit represented by formula (2):

##STR00001##

where R.sub.1 is a C.sub.3-C.sub.10 alkylene group, and R.sub.2 is an alicyclic group. In the present disclosure, a specific alicyclic monomer is introduced into the aliphatic polycarbonate molecular chain to obtain a novel aliphatic copolycarbonate. The polymer in the present disclosure has properties such as relatively high melting point, glass transition temperature and thermal stability, and has better thermal properties.

The present invention relates to a pouch exterior material which is for a lithium secondary battery and includes an inner layer, an outer resin layer, and a metal layer located between the inner layer and the outer resin layer, wherein the inner layer contains an ethylenically unsaturated group, and a lithium secondary battery including the pouch exterior material.

The present disclosure is directed to injectable formulations that include biodegradable polymers based on trimethylene carbonate (TMC) with mole fractions of polylactic acid (PLA) and/or polyglycolic acid (PGA) that are used to deliver a bioactive agent to a targeted site. Excipients such as polyethylene glycol (PEG) may be added to the formulations to reduce the injection force and/or to modulate the release of the bioactive agent. Suitable biodegradable polymers for use in the injectable formulations include D,L-PLA:TMC, D-PLA:TMC, L-PLA:TMC, TMC:PLA:PGA and variations thereof. Additionally, copolymers of TMC and PLA and terpolymers of TMC:PLA:PGA may be formed into nanoparticles and delivered to the target site with an injectable crosslinkable polyethylene glycol system. In at least one embodiment, the injectable formulations are used to treat ocular diseases.

A biodegradable triblock copolymer comprising: an A-B-A′ structure wherein the A and A′ blocks each include polylactide, the B block includes from about 55 to about 100 mole percent of polytrimethylene carbonate and 0 to about 45 mole percent polylactide, and the biodegradable triblock copolymer overall includes from about 15 to about 25 mole percent of the polytrimethylene carbonate and from about 75 to about 85 mole percent of the polylactide. Also provided are compositions and implantable medical devices made therefrom.

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.

A polycarbonate polyol represented by the following Formula (A-1):

##STR00001##

[in Formula (A-1), R.sup.1 represents a hydrogen atom, an alkyl group or a hydroxyalkyl group, R.sup.2 represents an alkanediyl group, n and m each represent an integer of 1 or more; and a plurality of R.sup.2's may be the same as or different from each other].

The present disclosure relates to polycarbonate a diol compound represented by Chemical Formula 1; at least one compound of compounds represented by Chemical Formulae 2 and 3; and a carbonate precursor-derived repeating unit, and a method for preparing the same.