CN1865321A - Heat-proof polylactic acid copolymer and method for preparing same - Google Patents
Heat-proof polylactic acid copolymer and method for preparing same Download PDFInfo
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- CN1865321A CN1865321A CN 200610027883 CN200610027883A CN1865321A CN 1865321 A CN1865321 A CN 1865321A CN 200610027883 CN200610027883 CN 200610027883 CN 200610027883 A CN200610027883 A CN 200610027883A CN 1865321 A CN1865321 A CN 1865321A
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Abstract
The invention discloses a heat-durability polylactic copolymer and preparing method, which is characterized by the following: the copolymer is 20,000-600,000 weight average molecular weight L-polylactic-D-polylactic segmented copolymer, wherein the weight rate in the L-polylactic-D-polylactic segmented copolymer is 95:5-5:95; the fusion point of the segmented copolymer reaches over 80 deg.c, which possesses excellent heat-durability to expand the appliance of polylactic product. '
Description
Technical field
The present invention relates to a kind of heat-proof polylactic acid copolymer and preparation method thereof, be specifically related to a kind of fusing point greater than L-poly(lactic acid)-D-polylactic-acid block copolymer of 180 ℃ and preparation method thereof.
Background technology
Poly(lactic acid) (PLA) is the straight chain aliphatic polyester that makes by synthetic, has the favorable biological degradability energy, and its synthesis material lactic acid is formed by biological fermentation, and degraded product is carbonic acid gas and water, so poly(lactic acid) is environmentally friendly.Poly(lactic acid) also has good biological blending and bioresorbable, has been considered to the most promising degradable high polymer material in medical field, and is at present very active to its research and development.Poly(lactic acid) prepares by direct polymerization lactic acid or the cyclisation dimer-rac-Lactide ring-opening polymerization by lactic acid forms.The lactic acid direct polycondensation method is difficult to the PLA of synthetic macromolecule amount, and rac-Lactide ring-opening polymerization method exists technology tediously long, the equipment complexity, and shortcomings such as cost height, too high cost has limited the production and the Application and Development of poly(lactic acid).
The existing prepared PLA of method exists the not good defective of thermostability, its fusing point all is no more than 180 ℃, often causes comparatively serious thermal destruction in the course of processing, causes the decline significantly of molecular weight, easy to change, problem such as severely degrade in the road course of processing of back.Poor heat resistance has limited the application of poly(lactic acid) polymer aspect film, fiber and resin.
Summary of the invention
The object of the present invention is to provide a kind of heat-proof polylactic acid copolymer, this multipolymer is the segmented copolymer greater than 180 ℃ of fusing points of having of D-poly(lactic acid) and L-poly(lactic acid).
Another object of the present invention is to provide this multipolymer the preparation method.
Heat-proof polylactic acid copolymer of the present invention refers to that weight-average molecular weight is L-poly(lactic acid)-D-polylactic-acid block copolymer of 20,000～600,000, and wherein the weight ratio of L-poly(lactic acid) and D-poly(lactic acid) is 95: 5～5: 95, preferred 75～50: 25～50; The weight-average molecular weight of L-poly(lactic acid) is 2,000～100,000, and degree of crystallinity is more than 30%.The weight-average molecular weight of D-poly(lactic acid) is 2,000～100,000, and degree of crystallinity is more than 30%.The fusing point of multipolymer is 180 ℃～230 ℃, and degree of crystallinity reaches 40 moles of %～70 mole %, and molecular weight distribution is 1.10～1.90.
With weight-average molecular weight is 2,000～100,000, degree of crystallinity is that L-poly(lactic acid) and weight-average molecular weight more than 30% are 2,000～100,000, degree of crystallinity is that D-poly(lactic acid) more than 30% is pulverized after with 95: 5～5: 95 part by weight blend, after the resulting granules shaped polymer decompression crystallization, the solid phase copolymerization of carrying out 25～60 hours under 130 ℃～160 ℃ temperature makes.
In the aforesaid method, described L-poly(lactic acid) and D-poly(lactic acid) are by direct fusion/solid state polymerization or the preparation of rac-Lactide ring-opening polymerization method.Wherein the direct polymerization method is carried out under the catalysis of polymerizing catalyst, and described polymerizing catalyst is acid, alkoxide or hydrochlorate, as methylsulfonic acid, Phenylsulfonic acid, aluminum isopropylate, aluminum methylate, tin chloride or stannous octoate etc.In addition, also can adopt composite catalyst such as trifluoracetic acid lanthanum, the trifluoracetic acid yttrium etc. of rare earth metal.The consumption of polymerizing catalyst is 3%～0.01% of a monomer consumption.
Because lactic acid is chiral molecules, its optical purity is very big to the regular shape influence of polymkeric substance.If the low then crystallizing power of poly(lactic acid) of optical purity will descend.In order to obtain the higher relatively polylactic acid low polymer of degree of crystallinity, the raw material that is used to prepare L-poly(lactic acid) or D-poly(lactic acid) should adopt optical purity to be higher than 80% L-lactic acid or D-lactic acid, and wherein optical purity is higher than lactic acid the best of 90%.
Described L-poly(lactic acid) and the preferred degree of crystallinity of D-poly(lactic acid) are more than 50%.Too small or non crystallized L-poly(lactic acid) of degree of crystallinity and D-poly(lactic acid) illustrate that there are side reactions such as serious racemize and transesterify in it in the pre-polymerization process, side reaction will aggravate in solid state polymerization processes subsequently, cause segmented copolymer can't crystallization or crystallizing power too small.
The blend of described L-poly(lactic acid) and D-poly(lactic acid) is adopted the heating and melting blending method, fully dissolves blending method or utilize the twin screw blending method in solution.Wherein the heating and melting blend is that L-poly(lactic acid) and D-poly(lactic acid) were mixed 10～45 minutes under 180 ℃～230 ℃ heating and meltings; The solvent that is used to dissolve blend can adopt trichloromethane or methylene dichloride.The preferred blend part by weight of described L-poly(lactic acid) and D-poly(lactic acid) is 75～50: 25～50.
The preferable particle size of the particulate polymers of described reduce pressure crystallization and the copolymerization of decompression solid phase is below 1 millimeter.
Beneficial effect
1, the fusing point of L-poly(lactic acid) of the present invention-D-polylactic-acid block copolymer reaches more than 180 ℃, thermotolerance is good, solved the easy to change of poly(lactic acid), problem such as severely degrade in the road course of processing of back, thereby expanded the application of poly-lactic acid products, especially enlarged its application aspect film, fiber and resin.
2, the inventive method have simple to operate, advantage such as production cost is low.
Embodiment
Below by embodiment the inventive method is further elaborated, but does not limit the present invention:
The gel permeation chromatograph (GPC) that weight-average molecular weight among the following embodiment (Mw) adopts Tianjin, island company to produce is measured, and probe temperature is 30 ℃, and moving phase is tetrahydrofuran (THF), and standard model is a polystyrene.
The TA-Q100 type differential scanning tester (DSC) that degree of crystallinity adopts TA company to produce is measured, under nitrogen atmosphere, with the variation in 0～230 ℃ of scope of 10 ℃/min temperature rise rate observation.The degree of crystallinity method of calculation are: Xc=Δ H
f/
0H
f, wherein Xc is a degree of crystallinity, Δ H
fExpression poly(lactic acid) crystallization melting enthalpy,
0H
fThe expression poly(lactic acid) is crystalline melting enthalpy (people such as Fisher report very
0H
fValue is about 93J/g).
The preparation of embodiment 1 lower molecular weight L-poly(lactic acid)
The L-lactic acid aqueous solution 1Kg that takes by weighing 90wt% stirring reaction 5 hours under 150 ℃, 30mmHg vacuum tightness adds the stannous octoate of 0.2wt% then in oligopolymer, reaction is 8 hours under 180 ℃, 13mmHg vacuum tightness.After the cooling, pulverize, after measured, the weight-average molecular weight of polymkeric substance is 21,000,165 ℃ of fusing points, and degree of crystallinity is 53.1%, optical purity is 98.00%ee.
The preparation of embodiment 2 lower molecular weight L-poly(lactic acid)
The L-lactic acid aqueous solution 1Kg that takes by weighing 90wt% stirring reaction 5 hours under 150 ℃, 30mmHg vacuum tightness adds the stannous octoate of 3.0wt% then in oligopolymer, reaction is 8 hours under 180 ℃, 13mmHg vacuum tightness.After the cooling, pulverize, after measured, the weight-average molecular weight of polymkeric substance is 9,000, and no crystallization does not have fusing point, and optical purity is 71.50%ee.
The preparation of embodiment 3 lower molecular weight D-poly(lactic acid)
The D-lactic acid aqueous solution 1Kg that takes by weighing 90wt% stirring reaction 5 hours under 150 ℃, 30mmHg vacuum tightness adds the stannous octoate of 0.2wt% then in oligopolymer, reaction is 8 hours under 180 ℃, 13mmHg vacuum tightness.After the cooling, pulverize, after measured, the weight-average molecular weight of polymkeric substance is 20,000,160 ℃ of fusing points, and degree of crystallinity is 48.4%, optical purity is 98.00%ee.
The preparation of embodiment 4 lower molecular weight D-poly(lactic acid)
The D-lactic acid aqueous solution 1Kg that takes by weighing 90wt% stirring reaction 5 hours under 150 ℃, 30mmHg vacuum tightness adds the stannous octoate of 3.0wt% then in oligopolymer, reaction is 8 hours under 180 ℃, 13mmHg vacuum tightness.After the cooling, pulverize, after measured, the weight-average molecular weight of polymkeric substance is 9,500, and no crystallization does not have fusing point, and optical purity is 68.30%ee.
Produce L-poly(lactic acid) and D-poly(lactic acid) according to embodiment 1 and embodiment 3 described methods respectively among the following embodiment 5-13.
The preparation of embodiment 5 L-poly(lactic acid)-D-polylactic-acid block copolymer
Take by weighing L-poly(lactic acid) 50g, D-poly(lactic acid) 50g, under the normal pressure, mixed 30 minutes 190 ℃ of heated and stirred.Cool off in the liquid nitrogen then, be ground into diameter particle below 1 millimeter, granulated polymer at 110 ℃, 1 kPa with crystallization under the overdraft 1.5 hours.Then, 1 kPa with solid state polymerization under the overdraft, under 150 ℃ of conditions 40 hours.After measured, the weight-average molecular weight of resulting L-poly(lactic acid)-D-polylactic-acid block copolymer is 230,000, fusing point is 198 ℃, and degree of crystallinity is 50.2%.
The preparation of embodiment 6 L-poly(lactic acid)-D-polylactic-acid block copolymer
Take by weighing L-poly(lactic acid) 70g, D-poly(lactic acid) 30g, under the normal pressure, mixed 30 minutes 190 ℃ of heated and stirred.Cool off in the liquid nitrogen then, be ground into diameter particle below 1 millimeter, granulated polymer at 110 ℃, 1 kPa with crystallization under the overdraft 1.5 hours.Then, 1 kPa with solid state polymerization under the overdraft, under 150 ℃ of conditions 40 hours.After measured, the weight-average molecular weight of resulting L-poly(lactic acid)-D-polylactic-acid block copolymer is 223,000, fusing point is 202 ℃, and degree of crystallinity is 49.2%.
The preparation of embodiment 7 L-poly(lactic acid)-D-polylactic-acid block copolymer
Take by weighing L-poly(lactic acid) 80g, D-poly(lactic acid) 20g, under the normal pressure, mixed 30 minutes 190 ℃ of heated and stirred.Cool off in the liquid nitrogen then, be ground into diameter particle below 1 millimeter, granulated polymer at 110 ℃, 1 kPa with crystallization under the overdraft 1.5 hours.1 kPa with solid state polymerization under the overdraft, under 150 ℃ of conditions 40 hours then.After measured, the weight-average molecular weight of resulting L-poly(lactic acid)-D-polylactic-acid block copolymer is 203,000, fusing point is 210 ℃, and degree of crystallinity is 50.1%.
The preparation of embodiment 8 L-poly(lactic acid)-D-polylactic-acid block copolymer
Take by weighing L-poly(lactic acid) 95g, D-poly(lactic acid) 5g, under the normal pressure, mixed 30 minutes 190 ℃ of heated and stirred.Cool off in the liquid nitrogen then, be ground into diameter particle below 1 millimeter, granulated polymer at 110 ℃, 1 kPa with crystallization under the overdraft 1.5 hours.1 kPa with solid state polymerization under the overdraft, under 150 ℃ of conditions 40 hours then.After measured, the weight-average molecular weight of resulting L-poly(lactic acid)-D-polylactic-acid block copolymer is 230,000, fusing point is 170 ℃, and degree of crystallinity is 48.9%.
The preparation of embodiment 9 L-poly(lactic acid)-D-polylactic-acid block copolymer
Take by weighing L-poly(lactic acid) 50g, D-poly(lactic acid) 50g, under the normal pressure, mixed 30 minutes 190 ℃ of heated and stirred.Cool off in the liquid nitrogen then, be ground into diameter particle below 1 millimeter, granulated polymer at 110 ℃, 1 kPa with crystallization under the overdraft 1.5 hours.1 kPa with solid state polymerization under the overdraft, under 150 ℃ of conditions 25 hours then.After measured, the weight-average molecular weight of resulting L-poly(lactic acid)-D-polylactic-acid block copolymer is 173,000, fusing point is 194 ℃, and degree of crystallinity is 47.1%.
The preparation of embodiment 10 L-poly(lactic acid)-D-polylactic-acid block copolymer
Take by weighing L-poly(lactic acid) 50g, D-poly(lactic acid) 50g, under the normal pressure, mixed 30 minutes 190 ℃ of heated and stirred.Cool off in the liquid nitrogen then, be ground into diameter particle below 1 millimeter, granulated polymer at 110 ℃, 1 kPa with crystallization under the overdraft 1.5 hours.1 kPa with solid state polymerization under the overdraft, under 150 ℃ of conditions 50 hours then.After measured, the weight-average molecular weight of resulting L-poly(lactic acid)-D-polylactic-acid block copolymer is 234,000, fusing point is 205 ℃, and degree of crystallinity is 46.7%.
The preparation of embodiment 11 L-poly(lactic acid)-D-polylactic-acid block copolymer
Take by weighing L-poly(lactic acid) 50g, D-poly(lactic acid) 50g, under the normal pressure, mixed 30 minutes 190 ℃ of heated and stirred.Cool off in the liquid nitrogen then, be ground into diameter particle below 1 millimeter, granulated polymer at 110 ℃, 1 kPa with crystallization under the overdraft 1.5 hours.1 kPa with solid state polymerization under the overdraft, under 150 ℃ of conditions 60 hours then.After measured, the weight-average molecular weight of resulting L-poly(lactic acid)-D-polylactic-acid block copolymer is 240,000, fusing point is 206 ℃, and degree of crystallinity is 45.6%.
The preparation of embodiment 12 L-poly(lactic acid)-D-polylactic-acid block copolymer
Take by weighing L-poly(lactic acid) 50g and place 1 liter of flask, add 283g trichloromethane dissolving L-poly(lactic acid), other takes by weighing D-poly(lactic acid) 12.5g and places 500 ml flasks, adds 71g trichloromethane dissolving D-poly(lactic acid).After treating that L-poly(lactic acid) and D-poly(lactic acid) are fully dissolved, above-mentioned two solution are mixed.Normal temperature stirs down removed the trichloromethane solvent in 30 minutes.Be ground into diameter particle below 1 millimeter then, granulated polymer at 110 ℃, 1 kPa with crystallization under the overdraft 1.5 hours.1 kPa with solid state polymerization under the overdraft, under 150 ℃ of conditions 40 hours then.After measured, the weight-average molecular weight of resulting L-poly(lactic acid)-D-polylactic-acid block copolymer is 220,000, fusing point is 225 ℃, and degree of crystallinity is 48.3%.
The preparation of embodiment 13 L-poly(lactic acid)-D-polylactic-acid block copolymer
Take by weighing L-poly(lactic acid) 50g and place 1 liter of flask, add 283g trichloromethane dissolving L-poly(lactic acid), other takes by weighing D-poly(lactic acid) 21.4g and places 500 ml flasks, adds 121g trichloromethane dissolving D-poly(lactic acid).After treating that L-poly(lactic acid) and D-poly(lactic acid) are fully dissolved, above-mentioned two solution are mixed.Normal temperature stirs down removed the trichloromethane solvent in 30 minutes.Be ground into diameter particle below 1 millimeter then, granulated polymer at 110 ℃, 1 kPa with crystallization under the overdraft 1.5 hours.1 kPa with solid state polymerization under the overdraft, under 150 ℃ of conditions 40 hours then.After measured, the weight-average molecular weight of resulting L-poly(lactic acid)-D-polylactic-acid block copolymer is 215,000, fusing point is 207 ℃, and degree of crystallinity is 43.3%.
Comparative example 1
Take by weighing L-rac-Lactide 100g and stannous octoate 0.2g places three-necked flask, sealed flask behind the nitrogen replacement 3 times.180 ℃ of following melt polymerizations 3 hours, pulverize the back at vacuum state, 150 ℃ of following solid state polymerizations 8 hours.After measured, the weight-average molecular weight of resulting L-poly(lactic acid) is 200,000, and fusing point is 175 ℃, and optical purity is 98.5%ee.
Comparative example 2
Take by weighing D-rac-Lactide 100g and stannous octoate 0.2g places three-necked flask, sealed flask behind the nitrogen replacement 3 times.180 ℃ of following melt polymerizations 3 hours, pulverize the back at vacuum state, 150 ℃ of following solid state polymerizations 8 hours.After measured, the weight-average molecular weight of resulting D-poly(lactic acid) is 220,000, and fusing point is 175 ℃, and optical purity is 98.5%ee.
Comparative example 3
Prepare the L-poly(lactic acid) according to embodiment 1 described method, 1 kPa with following 150 ℃ of following solid state polymerizations of overdraft 30 hours, and after measured, the weight-average molecular weight of resulting L-poly(lactic acid) is 250,000, and fusing point is 174 ℃, and optical purity is 97.5%ee.
Comparative example 4
Prepare the D-poly(lactic acid) according to embodiment 3 described methods, 1 kPa with following 150 ℃ of following solid state polymerizations of overdraft 30 hours, and after measured, the weight-average molecular weight of resulting D-poly(lactic acid) is 220,000, and fusing point is 172 ℃, and optical purity is 97.7%ee.
Comparative example 5
Prepare L-poly(lactic acid) and D-poly(lactic acid) according to embodiment 2 and embodiment 4 described methods respectively, take by weighing L-poly(lactic acid) 50g, D-poly(lactic acid) 50g, under the normal pressure, mixed 30 minutes 190 ℃ of heated and stirred.Cool off in the liquid nitrogen then, be ground into diameter particle below 1 millimeter, granulated polymer at 110 ℃, 1 kPa with crystallization under the overdraft 1.5 hours.1 kPa with solid state polymerization under the overdraft, under 150 ℃ of conditions 40 hours then.After measured, the weight-average molecular weight of resulting L-poly(lactic acid)-D-polylactic-acid block copolymer is 103,000, no fusing point, and degree of crystallinity is 0.
Comparative example 6
Prepare L-poly(lactic acid) and D-poly(lactic acid) according to embodiment 2 and embodiment 4 described methods respectively, take by weighing L-poly(lactic acid) g0g, D-poly(lactic acid) 20g, under the normal pressure, mixed 30 minutes 190 ℃ of heated and stirred.Cool off in the liquid nitrogen then, be ground into diameter particle below 1 millimeter,, granulated polymer at 110 ℃, 1 kPa with crystallization under the overdraft 1.5 hours.Then, 1 kPa with solid state polymerization under the overdraft, under 150 ℃ of conditions 40 hours.After measured, the weight-average molecular weight of resulting L-poly(lactic acid)-D-polylactic-acid block copolymer is 97,000, no fusing point, and degree of crystallinity is 0.
Claims (9)
1. a heat-proof polylactic acid copolymer is characterized in that this multipolymer is that weight-average molecular weight is L-poly(lactic acid)-D-polylactic-acid block copolymer of 20,000～600,000, and wherein the weight ratio of L-lactic acid composition and D-lactic acid composition is 95: 5～5: 95.
2, heat-proof polylactic acid copolymer according to claim 1, the weight ratio that it is characterized in that L-poly(lactic acid) and D-poly(lactic acid) is 75～50: 25～50.
3, heat-proof polylactic acid copolymer according to claim 1, the weight-average molecular weight that it is characterized in that the L-poly(lactic acid) is 2,000～100,000, degree of crystallinity is more than 30%, and the weight-average molecular weight of D-poly(lactic acid) is 2,000～100,000, degree of crystallinity is more than 30%.
4, heat-proof polylactic acid copolymer according to claim 3 is characterized in that L-poly(lactic acid) and D-poly(lactic acid) are 50 moles of above crystallizations of %.
5, the preparation method of the described heat-proof polylactic acid copolymer of claim 1, it is characterized in that may further comprise the steps: with weight-average molecular weight is 2,000～100,000, degree of crystallinity is that L-poly(lactic acid) and weight-average molecular weight more than 30% are 2,000～100,000, degree of crystallinity is that D-poly(lactic acid) more than 30% is pulverized after with 95: 5～5: 95 part by weight blend, and after the resulting granules shaped polymer decompression crystallization, the solid phase copolymerization of carrying out 25～60 hours under 130 ℃～160 ℃ temperature makes.
6. the preparation method of heat-proof polylactic acid copolymer according to claim 5 is characterized in that the heating and melting blending method is adopted in the blend of described L-poly(lactic acid) and D-poly(lactic acid), fully dissolves blending method or utilize the twin screw blending method in solution.
7. the preparation method of heat-proof polylactic acid copolymer according to claim 6 is characterized in that the heating and melting blend is that L-poly(lactic acid) and D-poly(lactic acid) were mixed 10～45 minutes under 180 ℃～230 ℃ heating and meltings.
8. the preparation method of heat-proof polylactic acid copolymer according to claim 6, the solvent that it is characterized in that being used to dissolving blend is trichloromethane or methylene dichloride.
9. the preparation method of heat-proof polylactic acid copolymer according to claim 5, the blend part by weight that it is characterized in that described L-poly(lactic acid) and D-poly(lactic acid) is 75～50: 25～50.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101302280B (en) * | 2007-05-10 | 2011-09-14 | 东丽纤维研究所（中国）有限公司 | Rare earth compound-containing L-lactic acid and D-lactic acid block copolymer, and preparation thereof |
| CN102266593A (en) * | 2011-07-27 | 2011-12-07 | 长春圣博玛生物材料有限公司 | Absorbable internal fracture fixing piece |
| CN108026426A (en) * | 2015-10-01 | 2018-05-11 | 普拉克生化公司 | Non-reacted hotmelt with hardening time modifier |
-
2006
- 2006-06-20 CN CN 200610027883 patent/CN1865321A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101302280B (en) * | 2007-05-10 | 2011-09-14 | 东丽纤维研究所（中国）有限公司 | Rare earth compound-containing L-lactic acid and D-lactic acid block copolymer, and preparation thereof |
| CN102266593A (en) * | 2011-07-27 | 2011-12-07 | 长春圣博玛生物材料有限公司 | Absorbable internal fracture fixing piece |
| CN108026426A (en) * | 2015-10-01 | 2018-05-11 | 普拉克生化公司 | Non-reacted hotmelt with hardening time modifier |
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