Method for the synthesis of environmentally degradable block copolymers
AssigneeChronopol, Inc.
InventorsDan W. Verser, Kevin H. Schilling, Xiaomao Chen
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Abstract
A method is provided for the synthesis of environmentally degradable block copolymers which includes the sequential polymerization of polymer-forming materials in the presence of one or more polymerization reaction accelerants and catalysts. The accelerants are a class of hydrogen-labile compounds which act as polymerization initiators and accelerate the polymerization rate significantly. The environmentally degradable block copolymers produced include those comprising segments of polymers of alkylene oxides, trimethylene carbonates, lactones and cyclic esters of hydroxycarboxylic acids.
Claims51
A method for synthesizing an environmentally degradable block copolymer, the method comprising the steps of:
- (a) polymerizing a first polymer-forming material selected from the group consisting of lactones, cyclic esters of hydroxycarboxylic acids, trimethylene carbonates, alkylene oxides and mixtures thereof, in the presence of a first polymerization accelerant and a first catalyst to form a first polymer;
- (b) combining said first polymer with a second polymer-forming material selected from the group consisting of cyclic esters of hydroxycarboxylic acids and mixtures thereof and a second polymerization accelerant, which can be the same as or different from said first polymerization accelerant, and a second catalyst, which can be the same as or different from said first catalyst;
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- (c) polymerizing said second polymer-forming material to form said environmentally degradable block copolymer.
A method for synthesizing an environmentally degradable block copolymer, the method comprising the steps of:
- (a) melt polymerizing .epsilon.-caprolactone in the presence of a polymerization accelerant and a catalyst at a temperature within the range of from about 150.degree. C. to about 210.degree. C. for a time period of less than about 65 minutes to form a poly(.epsilon.-caprolactone) polymer;
- (b) mixing said poly(.epsilon.-caprolactone) polymer with an amount of a polymer-forming material selected from the group consisting of lactide, glycolide and mixtures thereof and an additional amount of said polymerization accelerant and an additional amount of said catalyst, such that the resulting mixture comprises from about 50 mole % to about 95 mole % said polymer-forming material;
- and
- (c) melt polymerizing said polymer-forming material at a temperature within the range of from about 150.degree. C. to about 210.degree. C. for a time period of less than about two hours to form an environmentally degradable block copolymer.
A method for synthesizing an environmentally degradable block copolymer, the method comprising the steps of:
- (a) providing a first environmentally degradable polymer-forming material having a glass transition temperature of less than about 10.degree. C. to a polymerization reactor;
- (b) polymerizing said environmentally degradable first polymer-forming material in the presence of a first catalyst and a first polymerization accelerant comprising a hydrogen-labile compound to form a first polymer;
- (c) combining a second polymer-forming material comprising a cyclic ester of a hydroxycarboxylic acid with said first polymer;
- and
- (d) polymerizing said second polymer-forming material in the presence of a second catalyst, which can be the same as or different from said first catalyst, and a second polymerization accelerant comprising a hydrogen-labile compound, which can be the same as or different from said first polymerization accelerant, to form said environmentally degradable block copolymer.
An environmentally degradable block copolymer comprising from about 5 mole % to about 50 mole % hard segments of a polymer of .epsilon.-caprolactone and from about 50 mole % to about 95 mole % soft segments of a polymer having repeating units of a material selected from the group consisting of lactide and glycolide, wherein said block copolymer is substantially colorless.
Dependencies are inferred from the claim text.