In-situ fiber-forming strengthened degradable medical elastic composite material and preparation method thereof
Technical field
The invention belongs to the high-molecular biologic field of medical materials.Specifically, the present invention relates to a kind of by polyglycolic acid [poly (glycolic acid), PGA] or poly-(L-lactic acid) [poly (L-lactic acid), PLLA] strengthen the preparation method of poly-(L-lactide-epsilon-coprolactone) [poly (L-lactide-co-ε-caprolactone), PLLCA] in-situ fibrillation degradable medical elastic composite material.
Background technology
Along with clinical medical continuous development, the bio-medical elastomeric material has obtained application more and more widely.At present, the medical elastomer of having reported mainly is divided into degradable medical elastic body and non-degradable elastomer two big classes.Wherein, the non-degradable elastomer mainly has silicone rubber medical elastomer, polyurethane medical elastomer etc., there are many deficiencies in the non-degradable medical elastomer in clinical practice, need second operation to take out as elastomer, increased operation risk when bringing very big misery to patient, because the biocompatibility of most of non-degradable material is relatively poor, foreign body reaction after implanting, usually occurs, thereby cause a series of complication in addition.Degradable elastomers mainly is divided into polyether ester bioelastomer, poly-peptide bioelastomer, hydrogel and polyesters bioelastomer etc., though the degradable medical elastic body has better biocompatibility at present, but production cost height, the processing conditions complexity, bad mechanical property, thus limited application clinically.
In view of the defective that exists in the prior art, it is low to the invention provides a kind of production cost, easy and simple to handle, the degradable medical elastic composite material of good biocompatibility.
Summary of the invention
The invention provides by polyglycolic acid or poly-(L-lactic acid) in-situ fibrillation and strengthen poly-(L-lactide-epsilon-coprolactone) degradable medical elastic composite material and preparation method thereof.
A kind of in-situ fiber-forming strengthened degradable medical elastic composite material adopts polyglycolic acid or poly-(L-lactic acid) as filler, and poly-(L-lactide-epsilon-coprolactone) prepares by the following method as matrix:
Is 20/80~5/95 premix with poly-(L-lactide-epsilon-coprolactone) by mass ratio with polyglycolic acid or poly-(L-lactic acid), in atmosphere of inert gases, utilizes extruding machine to extrude, and the screw speed of extruding machine is 10~80r/min; Extrude the back and draw with the hauling speed of 1~30m/min with traction machine, the value of control port mould diameter/batten diameter (draw ratio) is 1~6, uses water quench cooling in the distraction procedure.
Wherein, the weight average molecular weight (M of poly-(L-lactide-epsilon-coprolactone)
w) be 10-60 ten thousand, 6-caprolactone unit molar percentage is 15%~30% in poly-(L-lactide-epsilon-coprolactone).The intrinsic viscosity of polyglycolic acid [η] is 1~5g/dl; Weight average molecular weight (the M of poly-(L-lactic acid)
w) be 10~1,000,000.
When satisfying the polyglycolic acid of above-mentioned molecular weight or viscosities or poly-(L-lactic acid) and poly-(L-lactide-epsilon-coprolactone) and cooperating, the melt viscosity ratio range of polyglycolic acid or poly-(L-lactic acid) and poly-(L-lactide-epsilon-coprolactone) helps the better fibre that becomes.If this ratio is too small, then do not become fiber; This ratio is excessive, and then the draw ratio of fiber can be very little.Therefore, by carrying out viscosity or molecular weight control, control the ratio of viscosities of the two melt, thereby be controlled to fibrid to the molecular weight control of poly-(L-lactide-epsilon-coprolactone) with to polyglycolic acid or poly-(L-lactic acid).
Control the intensity of composite among the present invention by the usage ratio of regulating polyglycolic acid or poly-(L-lactic acid) and poly-(L-lactide-epsilon-coprolactone).The increase of fiber content in the composite, the hot strength of material present elder generation and increase the trend that afterwards reduces, and an amount of fiberfill fibers can play potentiation to material; If but fiber content is excessive, can make to form between fiber and reunite, in material, form defective, cause the mechanical property of materials to descend.Polyglycolic acid or poly-(L-lactic acid) are controlled to be 20/80~5/95 with the mass ratio of poly-(L-lactide-epsilon-coprolactone) among the present invention, compare with single poly-(L-lactide-epsilon-coprolactone), and the intensity of composite elastic body has had obvious enhancing.
Among the present invention by control port mould diameter/batten diameter (draw ratio) in 1~6 performance of controlling the composite elastic body that makes.Specifically, can regulate port mould diameter/batten diameter (draw ratio) by the screw speed of adjusting extruding machine and the hauling speed of traction machine.The screw speed of extruding machine has direct influence to fibre diameter size in the composite.Along with screw speed increases, the probability that dispersed phase drop collides mutually reduces, and the fibre diameter that forms after dispersed phase drop is stretched like this can be very little; But then, excessive rotating speed can be given the bigger shearing force of polymer melt, easily causes depolymerization.The screw speed of extruding machine is 10~80r/min among the present invention.The hauling speed of traction machine is also influential to fibre diameter size in the composite.Hauling speed is big more, and the diameter of rod of then extruding is more little, and fiber is stretched obvious more in the composite.But then, if the fiber draw ratio is excessive in the composite, in secondary operations or material use, fiber ruptures easily, produces defective at material internal.The hauling speed of traction machine is 1~30m/min among the present invention.The diameter of the composite that makes is 100nm~500nm, and fiber has partial fusion mutually and between matrix, and the boundary effect is stronger.
Fiber in the In-situ Composite of the present invention mainly forms extrude and extrude two processes of rear haulage from the mouth mould.Therefore, also important influence of the temperature of extrusion process.The present invention adopts general many temperature provinces that material is heated, and to the mouth mould, is divided into four humidity provinces of I-IV from the charging aperture of screw rod end, and IV district temperature is a die temperature.The temperature set-up mode in four zones is undertaken by mode common in the prior art.Take to increase earlier the mode that afterwards reduces, the first material premix that under lower slightly temperature (I district temperature), makes, make that then material melt extrudes, usually can get lower temperature under the complete fused prerequisite at the assurance filler, be the fusing point that the temperature that melt extrudes process behind the premix is not less than filler, be preferably the fusing point of filler or a little more than the fusing point of filler.When filler is polyglycolic acid, complete 230 ℃ of left and right sides fusions; When filler is poly-(L-lactic acid), complete 180 ℃ of left and right sides fusions.According to the molecular weight difference, the filler fusing point can be slightly different.
Wherein noble gas can be various noble gases commonly used, preferred nitrogen.
Because the melt viscosity of In-situ Composite is lower, the processing characteristics of composite is improved, and processing temperature is lower, and melt is littler to the wearing and tearing of equipment inwall in the course of processing.Carry out secondary operations after will making the In-situ Composite shear granulation, processing temperature is about 140 ℃, can be processed into material requested arbitrarily such as tubing, bar, sheet material and profile shapes.
Polyglycolic acid of the present invention or poly-(L-lactic acid) in-situ fibrillation strengthen poly-(L-lactide-epsilon-coprolactone) composite can be widely used in the medical elastomer field, is used to prepare medical apparatus and instruments such as degradable medical conduit, degradable elasticity fascia, degradable artificial skin.Particularly when producing the degradable conduit, because fento is to form on the spot in the conduit molding, therefore, fento can be height-oriented along the conduit axial direction, thereby make the hot strength increase of conduit more obvious, and other short fiber reinforcing materials are isotropic, can't compare with in-situ fibrillation reinforcing material of the present invention.
The present invention avoids adopting general thermotropic liquid crystal as fibre-forming material, thereby has broken through general fibre-forming material because the high and non-degradable of price is difficult to the restriction applied in the degradable medical field.The present invention will have preferably crystallizing power and hot strength degradable biological medical material polyglycolic acid and poly-(L-lactic acid) as reinforcing material (fibre-forming material), with poly-(L-lactide-epsilon-coprolactone) matrix blend processing, the reinforcing material and the matrix compatibility are suitable, too poor system can't realize reinforced effects both to have avoided the compatibility, avoided the two complete consolute in the very good system of the compatibility to cause forming the defective of fiber again, reinforcing material fully disperses in matrix; Poly-(L-lactic acid) processing temperature of reinforcing material is about 180 ℃, the processing temperature of polyglycolic acid is about 230 ℃, the processing temperature of matrix is about 140 ℃, because the processing temperature that temperature will be equal to or higher than matrix during the composite secondary operations makes the matrix fusion, but the processing temperature that will be lower than fibre-forming material simultaneously is held in the fibre morphology of fiber material, so the composite fabricating temperature is between the processing temperature of matrix and fibre-forming material, and the processing temperature difference of reinforcing material and base material is enough big among the present invention, thereby has guaranteed the composite fabricating temperature scope of broad; In the course of processing, wild phase is orientated the formation fento on the spot, in-situ fibrillation obtains fiber-reinforced polymer, the fiber reinforcement phase diameter that the polyglycolic acid that obtains like this or poly-(L-lactic acid) in-situ fibrillation strengthen in poly-(L-lactide-epsilon-coprolactone) composite is littler, combine better off with the interface of matrix, easier dispersion in matrix material; The reinforcing material crystal property is good simultaneously, avoids fiber to form after-contraction, makes the loss of fiber draw ratio; Material coextrusion after-drawing helps the formation of fortifying fibre; The fento diameter is little of submicron order in the In-situ Composite that finally obtains, and is 100nm~500nm among the present invention, and melt viscosity obviously descends, and processability is better.
Strengthen polymer composite with traditional fibre and compare, it is a kind of medical material that can complete biodegradable that polyglycolic acid of the present invention or poly-(L-lactic acid) in-situ fibrillation strengthen poly-(L-lactide-epsilon-coprolactone) composite; Directly add the fibre-reinforced high molecular composite with tradition and compare, the fiber phase diameter that polyglycolic acid of the present invention or poly-(L-lactic acid) in-situ fibrillation strengthen poly-(L-lactide-epsilon-coprolactone) composite is thinner, and diameter is 100nm~500nm; Fiber has partial fusion mutually and between matrix, and the boundary effect is stronger; Polyglycolic acid of the present invention or poly-(L-lactic acid) in-situ fibrillation strengthen poly-(L-lactide-epsilon-coprolactone) composite and have clear improvement than simple poly-(L-lactide-epsilon-coprolactone) on mechanical performance, and the hot strength of composite can increase by 20~50%; In addition, the melt viscosity that polyglycolic acid of the present invention or poly-(L-lactic acid) in-situ fibrillation strengthen poly-(L-lactide-epsilon-coprolactone) composite is lower, can alleviate in the course of processing melt effectively to the wearing and tearing of equipment cavity inner wall.
The specific embodiment
Embodiment 1
Is 5/95 premix with poly-(L-lactide-epsilon-coprolactone) by mass ratio with polyglycolic acid, in nitrogen atmosphere, utilizes single multiple screw extruder to extrude, and the extruding machine temperature is set to: (I) district is 220 ℃, and (II) district is 240 ℃, and (III) district is 230 ℃, and (IV) district is 230 ℃; The extruder screw rotating speed is 10r/min; Extrude the back and draw with the hauling speed of 1.8m/min with traction machine, control draw ratio (port mould diameter/batten diameter) is 3, uses water quench cooling in the distraction procedure, obtains the polyglycolic acid in-situ fibrillation and strengthens poly-(L-lactide-epsilon-coprolactone) composite.Poly-(L-lactide-epsilon-coprolactone) weight average molecular weight (M
w) be 15.5 ten thousand, wherein 6-caprolactone unit mole percent is 15%; The intrinsic viscosity of polyglycolic acid [η] is 1.5g/dl.Test result shows: poly-(L-lactide-epsilon-coprolactone) hot strength is 28.2MPa; The hot strength of the polyglycolic acid of gained/poly-(L-lactide-epsilon-coprolactone) is 33.2MPa, and elongation at break is 590%.
Embodiment 2
Is 10/90 premix with poly-(L-lactide-epsilon-coprolactone) by mass ratio with polyglycolic acid, in nitrogen atmosphere, utilizes single multiple screw extruder to extrude, the extruding machine temperature is set to: (I) district is 220 ℃, (II) district is 240 ℃, and (III) district is 230 ℃, and (IV) district is 230 ℃; The extruder screw rotating speed is 20r/min; Extrude the back and draw with the hauling speed of 3.7m/min with traction machine, control draw ratio (port mould diameter/batten diameter) is 3, uses water quench cooling in the distraction procedure, obtains the polyglycolic acid in-situ fibrillation and strengthens poly-(L-lactide-epsilon-coprolactone) composite.Wherein, poly-(L-lactide-epsilon-coprolactone) weight average molecular weight (M
w) be 28.4 ten thousand, 6-caprolactone unit mole percent is 18%; The intrinsic viscosity of polyglycolic acid [η] is 2.1g/dl.Test result shows: poly-(L-lactide-epsilon-coprolactone) hot strength is 25.1MPa; The hot strength of poly-(L-the lactide-epsilon-coprolactone)/polyglycolic acid of gained is 33.4MPa, and elongation at break is 568%.
Embodiment 3
Is 10/90 premix with poly-(L-lactide-epsilon-coprolactone) by mass ratio with polyglycolic acid, in nitrogen atmosphere, utilizes single multiple screw extruder to extrude, the extruding machine temperature is set to: (I) district is 220 ℃, (II) district is 240 ℃, and (III) district is 230 ℃, and (IV) district is 230 ℃; The extruder screw rotating speed is 25r/min; Extrude the back and draw with the hauling speed of 8.3m/min with traction machine, control draw ratio (port mould diameter/batten diameter) is 4, uses water quench cooling in the distraction procedure, obtains the polyglycolic acid in-situ fibrillation and strengthens poly-(L-lactide-epsilon-coprolactone) composite.Wherein, poly-(L-lactide-epsilon-coprolactone) weight average molecular weight (M
w) be 40.3 ten thousand, 6-caprolactone unit mole percent is 22%; The intrinsic viscosity of polyglycolic acid [η] is 2.6g/dl.Test result shows: poly-(L-lactide-epsilon-coprolactone) hot strength is 26.1MPa; The hot strength of poly-(L-the lactide-epsilon-coprolactone)/polyglycolic acid of gained is 36.4MPa, and elongation at break is 572%.
Embodiment 4
Is 15/85 premix with poly-(L-lactide-epsilon-coprolactone) by mass ratio with polyglycolic acid, in nitrogen atmosphere, utilizes single multiple screw extruder to extrude, the extruding machine temperature is set to: (I) district is 220 ℃, (II) district is 240 ℃, and (III) district is 230 ℃, and (IV) district is 230 ℃; The extruder screw rotating speed is 30r/min; Extrude the back and draw with the hauling speed of 14.8m/min with traction machine, control draw ratio (port mould diameter/batten diameter) is 5, uses water quench cooling in the distraction procedure, obtains the polyglycolic acid in-situ fibrillation and strengthens poly-(L-lactide-epsilon-coprolactone) composite.Wherein, poly-(L-lactide-epsilon-coprolactone) weight average molecular weight (M
w) be 48.1 ten thousand, 6-caprolactone unit mole percent is 25%, the intrinsic viscosity of polyglycolic acid [η] is 3.5g/dl.Test result shows: poly-(L-lactide-epsilon-coprolactone) hot strength is 22.4MPa; The hot strength of poly-(L-the lactide-epsilon-coprolactone)/polyglycolic acid of gained is 38.4MPa, and elongation at break is 536%.
Embodiment 5
Is 20/80 premix with poly-(L-lactide-epsilon-coprolactone) by mass ratio with polyglycolic acid, in nitrogen atmosphere, utilizes single multiple screw extruder to extrude, the extruding machine temperature is set to: (I) district is 220 ℃, (II) district is 240 ℃, and (III) district is 230 ℃, and (IV) district is 230 ℃; The extruder screw rotating speed is 35r/min; Extrude the back and draw with the hauling speed of 12.2m/min with traction machine, control draw ratio (port mould diameter/batten diameter) is 4, uses water quench cooling in the distraction procedure, obtains the polyglycolic acid in-situ fibrillation and strengthens poly-(L-lactide-epsilon-coprolactone) composite.Wherein, poly-(L-lactide-epsilon-coprolactone) weight average molecular weight (M
w) be 30.3 ten thousand, 6-caprolactone unit mole percent is 20%; The intrinsic viscosity of polyglycolic acid [η] is 4.1g/dl.Test result shows: poly-(L-lactide-epsilon-coprolactone) hot strength is 25.4MPa; The hot strength of poly-(L-the lactide-epsilon-coprolactone)/polyglycolic acid of gained is 31.1MPa, and elongation at break is 472%.
Embodiment 6
To gather (L-lactic acid) is 5/95 premix with poly-(L-lactide-epsilon-coprolactone) by mass ratio, in nitrogen atmosphere, utilizes single multiple screw extruder to extrude, the extruding machine temperature is set to: (I) district is 170 ℃, (II) district is 190 ℃, and (III) district is 180 ℃, and (IV) district is 180 ℃; The extruder screw rotating speed is 10r/min; Extrude the back and draw with the hauling speed of 2.1m/min with traction machine, control draw ratio (port mould diameter/batten diameter) is 3, uses water quench cooling in the distraction procedure, is gathered (L-lactic acid) in-situ fibrillation and strengthens poly-(L-lactide-epsilon-coprolactone) composite.Wherein, poly-(L-lactide-epsilon-coprolactone) weight average molecular weight (M
w) be 15.5 ten thousand, 6-caprolactone unit mole percent is 15%; Weight average molecular weight (the M of poly-(L-lactic acid)
w) be 20.4 ten thousand.Test result shows: poly-(L-lactide-epsilon-coprolactone) hot strength is 28.2MPa; The hot strength of poly-(the L-lactide-epsilon-coprolactone) of gained/poly-(L-lactic acid) is 21.4MPa, and elongation at break is 694%.
Embodiment 7
To gather (L-lactic acid) is 10/90 premix with poly-(L-lactide-epsilon-coprolactone) by mass ratio, in nitrogen atmosphere, utilizes single multiple screw extruder to extrude, the extruding machine temperature is set to: (I) district is 170 ℃, (II) district is 190 ℃, and (III) district is 180 ℃, and (IV) district is 180 ℃; The extruder screw rotating speed is 20r/min; Extrude the back and draw with the hauling speed of 4.1m/min with traction machine, control draw ratio (port mould diameter/batten diameter) is 3, uses water quench cooling in the distraction procedure, is gathered (L-lactic acid) in-situ fibrillation and strengthens poly-(L-lactide-epsilon-coprolactone) composite.Wherein, poly-(L-lactide-epsilon-coprolactone) weight average molecular weight (M
w) be 28.4 ten thousand, 6-caprolactone unit mole percent is 18%; Weight average molecular weight (the M of poly-(L-lactic acid)
w) be 45.3 ten thousand.Test result shows: poly-(L-lactide-epsilon-coprolactone) hot strength is 25.1MPa; The hot strength of poly-(the L-lactide-epsilon-coprolactone) of gained/poly-(L-lactic acid) is 32.3MPa, and elongation at break is 582%.
Embodiment 8
To gather (L-lactic acid) is 10/90 premix with poly-(L-lactide-epsilon-coprolactone) by mass ratio, in nitrogen atmosphere, utilizes single multiple screw extruder to extrude, the extruding machine temperature is set to: (I) district is 170 ℃, (II) district is 190 ℃, and (III) district is 180 ℃, and (IV) district is 180 ℃; The extruder screw rotating speed is 25r/min; Extrude the back and draw with the hauling speed of 8.5m/min with traction machine, control draw ratio (port mould diameter/batten diameter) is 4, uses water quench cooling in the distraction procedure, is gathered (L-lactic acid) in-situ fibrillation and strengthens poly-(L-lactide-epsilon-coprolactone) composite.Wherein, poly-(L-lactide-epsilon-coprolactone) weight average molecular weight (M
w) be 40.3 ten thousand, 6-caprolactone unit mole percent is 22%; Weight average molecular weight (the M of poly-(L-lactic acid)
w) be 58.6 ten thousand.Test result shows: poly-(L-lactide-epsilon-coprolactone) hot strength is 26.1MPa; The hot strength of poly-(the L-lactide-epsilon-coprolactone) of gained/poly-(L-lactic acid) is 35.1MPa, and elongation at break is 583%.
Embodiment 9
To gather (L-lactic acid) is 15/85 premix with poly-(L-lactide-epsilon-coprolactone) by mass ratio, in nitrogen atmosphere, utilizes single multiple screw extruder to extrude, the extruding machine temperature is set to: (I) district is 170 ℃, (II) district is 190 ℃, and (HI) district is 180 ℃, and (IV) district is 180 ℃; The extruder screw rotating speed is 30r/min; Extrude the back and draw with the hauling speed of 15.5m/min with traction machine, control draw ratio (port mould diameter/batten diameter) is 5, uses water quench cooling in the distraction procedure, is gathered (L-lactic acid) in-situ fibrillation and strengthens poly-(L-lactide-epsilon-coprolactone) composite.Wherein, poly-(L-lactide-epsilon-coprolactone) weight average molecular weight (M
w) be 48.1 ten thousand, 6-caprolactone unit mole percent is 25%; Weight average molecular weight (the M of poly-(L-lactic acid)
w) be 77.5 ten thousand.Test result shows: poly-(L-lactide-epsilon-coprolactone) hot strength is 22.4MPa; The hot strength of poly-(the L-lactide-epsilon-coprolactone) of gained/poly-(L-lactic acid) is 46.3MPa, and elongation at break is 557%.
Embodiment 10
To gather (L-lactic acid) is 20/80 premix with poly-(L-lactide-epsilon-coprolactone) by mass ratio, in nitrogen atmosphere, utilizes single multiple screw extruder to extrude, the extruding machine temperature is set to: (I) district is 170 ℃, (II) district is 190 ℃, and (III) district is 180 ℃, and (IV) district is 180 ℃; The extruder screw rotating speed is 35r/min; Extrude the back and draw with the hauling speed of 15.1m/min with traction machine, control draw ratio (port mould diameter/batten diameter) is 4, uses water quench cooling in the distraction procedure, is gathered (L-lactic acid) in-situ fibrillation and strengthens poly-(L-lactide-epsilon-coprolactone) composite.Wherein, poly-(L-lactide-epsilon-coprolactone) weight average molecular weight (M
w) be 30.3 ten thousand, 6-caprolactone unit mole percent is 20%; Weight average molecular weight (the M of poly-(L-lactic acid)
w) be 94.5 ten thousand.Test result shows: poly-(L-lactide-epsilon-coprolactone) hot strength is 25.4MPa; The hot strength of poly-(the L-lactide-epsilon-coprolactone) of gained/poly-(L-lactic acid) is 31.3MPa, and elongation at break is 496%.