摘要:
An optically active block polyester copolymer formed of structural units represented by the following general formulas (I) and (II): ##STR1## wherein represents for an asymmetric carbon atom and m and n each represents a natural number in the range of from 300 to 5000 is obtained by subjecting an optically active butyrolactone and a species of lactone other than the optically active butyrolactone to sequential ringopening copolymerization in the presence of a catalyst. This optically active block polyester copolymer possesses a high molecular weight and a high melting point (not less than 130.degree. C.) and forms a biodegradable and hydrolyzable material of high strength capable of tolerating the impacts of actual use.
摘要:
The biodegradable composition comprises at least poly(beta-hydroxybutyric acid) or a biodegradable copolymer thereof and a stereospecifically regular block copolymer having the structure units of formula (I): ##STR1## where R1 is a hydrocarbon group having 1 to 14 carbon atoms, optionally including double bonds, oxygen atoms or both of them; and m and n are respectively an integer ranging from 300 to 5,000, or having the structure units of formula (II): ##STR2## where R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are either a hydrogen atom or a methyl group; and m and n are respectively an integer ranging from 300 to 5,000.
摘要:
The block copolymer of polyesters and polycarbonates comprises at least one of each of the constituting units of (I) and (II) having the general formulae: ##STR1## where the sign * indicates an asymmetric carbon atom; R.sub.1, R.sup.2, R.sup.3 and R.sup.4 are either a hydrogen atom or a methyl group; m and n are respective a natural numbers ranging from 300 to 5000: The block copolymer is obtained by successive ring-opening and copolymerization of optically active .beta.-butyrolactones and cyclic carbonates in the presence of a catalyst.The block polymer obtained has high molecular weight and high melting temperature, and can thus be used as a high strength material for practical use and which has bio-degradable and hydrolyzable nature.
摘要:
A biodegradable, optically active copolymer is disclosed. The copolymer is represented by general formula (I): ##STR1## wherein R.sup.1 represents a group selected from the group consisting of methyldimethylene, 1,2-dimethyldimethylene, 1,1-dimethyldimethylene, methyltrimethylene, tetramethylene, methyltetramethylene, pentamethylene, 1,4-dimethyl-2-oxo-3-oxytetramethylene, 2-oxo-3-oxytetramethylene, and 2-methyl-3-oxypentamethylene, and m and n each represents a natural number of from 10 to 15,000. According to the present invention, useful polymers which are a new type of functional materials characterized as having optical activity, biodegradability (enzymatic degradability), and hydrolyzability can be easily produced in an industrially advantageous manner by the ring-opening copolymerization of optically active .beta.-butyrolactone with various lactones.
摘要:
A biodegradable optically active copolymer is disclosed, which is represented by the general formula (I): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represents a hydrogen atom or a methyl group; m and n each represents a natural number wherein the sum thereof gives 10 to 5,000; and C* represents an asymmetric carbon atom, and a process for producing the copolymer by ring-opening copolymerization of optically active .beta.-butyrolactone with a cyclic carbonate in the presence of catalyst. The biodegradable optically active copolymer of the present invention provides excellent biodegradability (enzyme degradability) and hydrolyzability.
摘要翻译:公开了一种可生物降解的光学活性共聚物,其由通式(I)表示:其中R 1,R 2,R 3和R 4各自表示氢原子或甲基; m和n各自表示其总和为10至5,000的自然数; C *表示不对称碳原子,以及在催化剂存在下通过光学活性β-丁内酯与环状碳酸酯开环共聚制备共聚物的方法。 本发明的生物降解性光学活性共聚物提供优异的生物降解性(酶降解性)和水解性。
摘要:
A process for producing poly(3-hydroxybutyric acid) comprising ring-opening polymerization of .beta.-butyrolactone is disclosed, wherein the ring-opening polymerization is carried out in the presence of at least one tin compound selected from the group consisting of a distannoxane derivative (e.g., 1-chloro-3-ethoxy-1,1,3,3-tetrabutyldistannoxane), a tin carboxylate compound (e.g., tin dioctanoate), and a di-lower alkyltin oxide (e.g., dibutyltin oxide). Poly(3-hydroxybutyric acid) can be produced in high yield at low cost through simple production steps. The resulting polymer has an increased molecular weight to a degree not heretofore attained.
摘要:
Novel 2,2'-bis(dicyclopentylphosphino)-1,1'-binaphthyl represented by formula (I): ##STR1## and a transition metal complex using the same as a ligand, are disclosed. The transition metal complex is industrially excellent as a catalyst for various asymmetric synthesis reactions.
摘要:
An optically active 7-substituted-1,4-dioxepan-5-one derivative represented by the general formula (I): ##STR1## wherein R represents an alkyl group having from 1 to 5 carbon atoms; and * means an asymmetric carbon atom, is disclosed. An optically active polymer represented by formula (II): ##STR2## wherein R and * are as defined above; and n is an integer of 25 or more, obtained by ring opening polymerization of the optically active 7-substituted-1,4-dioxepan-5-one derivative represented by formula (I) is also disclosed. A process for producing the optically active polymer represented by formula (II) is further disclosed, comprising subjecting an optically active 7-substituted-1,4-dioxepan-5-one derivative represented by formula (I) to ring opening polymerization in the presence of at least one catalyst selected from the group consisting of (i) an organotin compound, (ii) an organoaluminum compound and water, and (iii) an organozinc compound and water.