CN117887227A

CN117887227A - PLA/PCL two-phase biopolymer composite material, preparation method thereof and PLA/PCL product

Info

Publication number: CN117887227A
Application number: CN202311630122.4A
Authority: CN
Inventors: 刘志刚; 卢翔; 邓衍宏; 吴浩; 隋淼; 卢久灵; 汪虎; 朱传彪; 盛梦杰; 颜祥禹; 李小龙; 肖洋
Original assignee: SUZHOU COFCO BIOCHEMICAL CO Ltd; Huazhong University of Science and Technology; Cofco Jilin Bio Chemical Technology Co Ltd
Current assignee: SUZHOU COFCO BIOCHEMICAL CO Ltd; Huazhong University of Science and Technology; Cofco Jilin Bio Chemical Technology Co Ltd
Priority date: 2023-11-30
Filing date: 2023-11-30
Publication date: 2024-04-16

Abstract

The invention belongs to the technical field of processing of biopolymer materials, and discloses a PLA/PCL two-phase biopolymer composite material, a preparation method thereof and a PLA/PCL product. The composite material comprises a core and a shell coated outside the core, wherein the core is PLA, the shell is PCL, the diameter of the core is 0.8-2.8 mu m, and the diameter of the shell is 2.7-7 mu m. The preparation method overcomes the defect that the melt blending equipment in the prior art is mainly a single-screw extruder and a double-screw extruder based on a shear deformation principle, and is easy to cause breakage and degradation of material molecular chains.

Description

PLA/PCL two-phase biopolymer composite material, preparation method thereof and PLA/PCL product

Technical Field

The invention belongs to the technical field of processing of biopolymer materials, and particularly relates to a PLA/PCL two-phase biopolymer composite material, a preparation method thereof and a PLA/PCL product.

Background

Because petroleum-based high polymer materials are not degradable, such as improper disposal, certain pollution to the environment is easily caused. The bio-based polymer materials, such as polylactic acid (PLA) and Polycaprolactone (PCL), have good mechanical properties and biocompatibility, are derived from organisms, can be completely degraded, and are becoming the most ideal environment-friendly polymer materials for replacing the traditional petroleum-based plastics.

However, the single type of bio-based polymer material has obvious performance defects, for example, PLA has high tensile strength and elastic modulus, but is brittle, poor in toughness, difficult to control in degradation period and limited in application range; PCL has certain defects in crystallization, mechanical properties, thermal stability and the like, and also limits a large number of applications. Therefore, the single type of biopolymer material and another type of biopolymer material need to be subjected to blending, copolymerization, plasticization and other modifications so as to improve the comprehensive mechanical properties and expand the application range.

The bio-based polymer material is sensitive to temperature and is easy to degrade at high temperature, so that the processing temperature window is narrow, and great constraint is caused to the melt blending processing of the bio-based polymer material.

The melt blending method is commonly adopted because of the advantages of simple operation, strong controllability, low cost and the like. The traditional melt blending equipment is mainly a single-screw extruder and a double-screw extruder based on the shear deformation principle, and in the polymer processing process, the shearing acting force of a screw on materials is perpendicular to the flow direction of the materials, so that the thermal mass transfer of a melt, the blending compatibilization of multiphase polymers and the regulation and control of a multiphase system micro-interface are not facilitated, and the shearing heat generation is large, the thermal mechanical process is long, and the breakage and degradation of material molecular chains are easy to cause.

Therefore, research and development of a PLA/PCL two-phase biopolymer composite material and a preparation method thereof have important significance.

Disclosure of Invention

The invention aims to overcome the defects that a melt blending device in the prior art is mainly a single-screw extruder and a double-screw extruder based on a shear deformation principle and is easy to cause breakage and degradation of a material molecular chain, and the defects that a multiphase blending biopolymer material is uneven in microstructure, poor in comprehensive performance and long in thermal mechanical history.

In order to achieve the above object, according to a first aspect of the present invention, there is provided a PLA/PCL two-phase biopolymer composite material, wherein the composite material includes a core and a shell coated outside the core, wherein the core is PLA, the shell is PCL, the diameter of the core is 0.8-2.8 m, and the diameter of the shell is 2.7-7 m.

The second aspect of the invention provides a preparation method of a PLA/PCL two-phase biopolymer composite material, wherein the preparation method comprises the following steps:

s1: uniformly mixing PLA and PCL to obtain a PLA/PCL mixture;

s2: and (3) the PLA/PCL mixture is subjected to melting, plasticizing, mixing, transporting and extruding treatment by a pulse positive stress extruder under the action of pulse positive stress, so as to obtain the PLA/PCL two-phase biopolymer composite material.

The third aspect of the invention provides a PLA/PCL two-phase biopolymer composite material prepared by the preparation method.

The invention provides a PLA/PCL product, wherein the PLA/PCL product is prepared from the PLA/PCL two-phase biopolymer composite material.

Through the technical scheme, the beneficial effects of the invention include:

According to the preparation method disclosed by the invention, a pulse positive stress extruder is adopted, under the action of pulse positive stress, in the method, a PLA/PCL two-phase biopolymer system is subjected to positive displacement pulsation continuous plasticizing blending with a velocity gradient vector approaching to a flowing direction, and continuous dynamic generation and evolution of a micro-interface in the PLA/PCL two-phase system can be effectively regulated and controlled, and a core-shell structure is formed, so that the problems of uneven microstructure, poor comprehensive performance, long thermomechanical process, easiness in degradation in a processing process and the like of the PLA/PCL two-phase blending biopolymer material are solved, and the prepared composite material has excellent tensile property and flexibility.

Drawings

FIG. 1 is a schematic diagram of a pulse positive stress extruder used in the preparation method of the present invention;

FIG. 2 is a cross-sectional view of an extrusion system of a pulsed positive stress extruder employed in the method of making the present invention;

FIG. 3 is a schematic diagram of the principle of pulsed normal stress processing of a pulsed normal stress extruder employed in the preparation method of the present invention;

FIG. 4 is a SEM image of the microtopography of the PLA/PCL composite material prepared in example 1 of the invention;

FIG. 5 is a schematic block diagram of a process flow for the preparation of the PLA/PCL composite material of the invention and a PLA/PCL article.

Description of the reference numerals

1-A frame; 2-an electric motor; a 3-coupling; 4-a power reduction distributor; 5-a hopper; 6-rotor; 7-a stator; 8-extrusion port.

Detailed Description

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

As described above, the first aspect of the present invention provides a PLA/PCL two-phase biopolymer composite material, wherein the composite material includes a core and a shell coated outside the core, wherein the core is PLA, the shell is PCL, the diameter of the core is 0.8-2.8 m, and the diameter of the shell is 2.7-7 m.

According to the invention, the diameter of the core is preferably 2.2-2.8 m; the diameter of the shell is 4.7-5.3 m.

According to the invention, the weight average molecular weight of PLA is 80000-120000g/mol, and the weight average molecular weight of polycaprolactone is 20000-40000g/mol; in the present invention, the weight average molecular weight of PLA was 100000g/mol, and the weight average molecular weight of polycaprolactone was 30000g/mol.

According to the invention, polylactic acid (PLA) is the main body, polycaprolactone (PCL) is the additive, and the viscosity of PLA is 2-5 times of the viscosity of PCL, preferably the viscosity of PLA is 3 times of the viscosity of PCL.

s1: uniformly mixing PLA and PCL to obtain a PLA/PCL mixture;

The inventors of the present invention found that: the preparation method comprises the steps of adopting a continuous blending preparation method of PLA/PCL two-phase biopolymer composite materials with a pulse positive stress effect, uniformly mixing polylactic acid (PLA) and Polycaprolactone (PCL) two biopolymer materials according to a proportion, and then adding the mixture into an extruder with the pulse positive stress effect for melt blending; the extruder with the pulse positive stress effect consists of an extrusion system, a power transmission system, a temperature control system, a rack system and the like, wherein the extrusion system mainly consists of a rotor with a cross section of a four-circle topological structure and a stator with a cross section of a five-circle topological inner cavity structure, and the power transmission system mainly consists of a motor, a coupler and a power speed reduction distributor; the motor drives the rotor to rotate in the inner cavity of the stator through the power speed reducing distributor, the revolution direction is opposite to the rotation direction, and the speed ratio is 1:4, compound motion; when the rotor rotates in the inner cavity of the stator, the topological spiral structure of the rotor can be meshed with the topological spiral structure of the inner cavity of the stator, and under the meshing action of the rotor and the stator, the positive pulse stress effect can be generated in the cavity of the extrusion system; the volume of the PLA and PCL blend is continuously compressed and released under the action of the pulse positive stress, so that the PLA and PCL blend is forced to do positive displacement pulsation flow with the velocity gradient vector approaching to the flow direction; the material in the cavity is continuously subjected to positive stress applied by the rotor and generates local high pressure, the volume of PLA/PCL melt is subjected to periodical compression release, the disperse phase is stretched into a fiber shape and then crushed into a smaller disperse phase, the disperse phase is evolved into a core-shell structure based on different viscosities of two phases, the gap between two phases is reduced, the stretching performance and the impact performance of the material are further improved, and the comprehensive performance of the material is improved.

According to the invention, the amount of PCL is 10-40 wt.% and the amount of PLA is 60-90 wt.%, based on the total amount of PLA and PCL; preferably, the amount of PCL is 20-30 wt.% and the amount of PLA is 70-80 wt.%, based on the total amount of PLA and PCL. Namely, the mass ratio of the contents of PLA and PCL (6-9): (1-4), preferably (7-8): (2-3).

According to the present invention, as shown in fig. 1, which is a schematic structural diagram of a pulse positive stress extruder used in the preparation method of the present invention, the pulse positive stress extruder includes a frame system, a power transmission system, a temperature control system, and an extrusion system.

According to the invention, the rack system comprises a rack 1.

According to the invention, the power transmission system comprises a motor 2, a coupling 3 and a power reduction distributor 4; the output shaft of the motor 2 is connected with the input shaft of the power reduction distributor 4 through the coupler 3; the motor 2 and the power reduction distributor 4 are fixedly connected to the bracket 1.

According to the invention, the temperature control system comprises a heating and cooling device, and the heating and cooling device is arranged outside the stator 7;

According to the invention, the extrusion system comprises a hopper 5, a rotor 6 and a stator 7; the rotor 6 is arranged in the inner cavity of the stator 7 and is connected with the output shaft of the power speed reducing distributor 4; one side of the stator 7 is fixedly connected with the power reduction distributor 4 by a connecting half, and the other side is supported by a stator support frame; the hopper 6 is arranged at the feed opening of the stator 7.

According to the invention, the rotor 6 is of a topology with continuously varying outer surface; the cross section of the rotor 6 is a curved topological quadrilateral; the outer surface of the rotor 6 comprises a helical section and a flat section, and the pitch of the helical section gradually decreases in the extrusion direction until reaching the flat section.

According to the invention, the inner cavity surface of the stator 7 is of a continuously variable topological structure; the cross section of the inner cavity of the stator 7 is curved Bian Tapu pentagons; the inner cavity surface of the stator 7 comprises a spiral section and a straight section, and the pitch of the spiral section gradually decreases along the extrusion direction until reaching the straight section; the spiral section and the straight section of the stator 7 correspond to the spiral section and the straight section of the rotor 6 one by one, and the lengths are the same; the pitch of each part of the helical section of the stator 7 is 1.25 times the pitch of the corresponding helical section of the rotor 6.

According to the invention, the outer topological surface of the rotor 6 is engaged with the inner topological surface of the inner cavity of the stator 7.

FIG. 2 is a cross-sectional view of an extrusion system of a pulsed positive stress extruder employed in the method of making the present invention, in accordance with the present invention; FIG. 3 is a schematic diagram of the principle of pulsed normal stress processing of a pulsed normal stress extruder employed in the preparation method of the present invention; as shown in fig. 2 and 3: when the motor works, the rotor (6) rotates under the drive of the power speed reducing distributor (4) and reversely revolves around the axis of the inner cavity of the stator (7) by taking the eccentric quantity e as a radius, and the revolution speed is 4 times of the rotation speed of the rotor; wherein the eccentric amount e is 1-8mm. The stator chamber will continuously perform compression release during rotation of the rotor. In the chamber of the stator 7, the rotor 6 gradually compresses, the force it exerts on the material gradually increases, the pressure reaches a maximum when the chamber volume is compressed to a minimum, and then when the rotor 6 is released, the chamber volume gradually increases, the pressure gradually decreases. When the rotor 6 is continuously operated in the stator 7 cavity, the material in the stator cavity is subjected to continuous pulsed positive stress.

According to the invention, the temperature control system is divided into five control zones on the stator 7 in the extrusion direction, the temperature of each control zone being in the range of 25 to 300 from room temperature, the temperature control accuracy being + -2 . Preferably, the first zone temperature is 100-110 , the second zone temperature is 120-150 , the third zone temperature is 140-170 , the fourth zone temperature is 140-170 , the fifth zone temperature is 150-180 , and the die heating zone temperature is 160-180 . More preferably, the processing temperature of the pulse positive stress extruder from the feed inlet to the die temperature is 100 , 120 , 140 , 150 , 165 , respectively.

According to the present invention, the rotation speed of the rotor 6 is 0 to 100rpm, and preferably the rotation speed of the rotor 6 is set to 50rpm.

According to the invention, PLA and PCL raw materials are fed from a hopper 5 into the inner cavity of a stator 7.

According to the invention, the conditions of positive stress of the pulses include: the pressure is 0.1-20MPa; preferably, the pressure is 3-15MPa; preferably, the cyclic pressure of the flat section is 2.5-14.5MPa, preferably 2.5-12MPa, preferably 2.5-10.5MPa; the periodical pressure of the spiral section is 0.5-8MPa, preferably 0.6-7.2MPa; more preferably, the pulse normal stress applied to the material in the spiral section and the straight section from the feeding area to the discharge port of the extruder is respectively 0.6+/-0.2 MPa in the spiral section, 2.5+/-0.3 MPa in the straight section, 3.5+/-0.2 MPa in the spiral section, 5.5+/-0.4 MPa in the straight section, 4.5+/-0.2 MPa in the spiral section, 10.5+/-0.5 MPa in the straight section and 7.2+/-0.3 MPa in the spiral section. In the present invention, the spiral section and the flat section are alternately formed, that is, the spiral section, the flat section, and the spiral section are alternately formed.

According to a particularly preferred embodiment of the present invention, a method for preparing a PLA/PCL two-phase biopolymer composite material comprises:

S1, mixing high polymer materials of PLA and PCL according to the mass fraction of the PCL not less than 5% and not more than 50%;

S2: and (2) adding the PLA/PCL mixture obtained in the step (S1) into an extruder with a pulsating ultrahigh pressure effect, and melting, plasticizing, mixing, transporting and extruding the mixture under the pulse positive stress effect of the extruder to obtain the PLA/PCL two-phase biopolymer composite material.

According to the invention, the PLA/PCL composite material prepared by an extruder under the action of pulse positive stress is cooled and shaped by a flat vulcanizing machine to prepare the product.

According to the invention, the temperature of the vulcanizing press is set to 165-180 , the exhaust is carried out for 2-10 times, the stroke is 1.5-2mm, and the pressure is 20-30MPa.

According to the present invention, the shapes of the resulting PLA/PCL composite articles include, but are not limited to, sheet, strip, pellet, plate and film.

The present invention will be described in detail by examples.

In the following examples and comparative examples:

the microscopic morphology of the composite material was observed by scanning electron microscopy (FE-SEM, hitachi SU 8010).

Impact strength was measured by a pendulum impact tester (model PTM7000, shenzhen , vertically and horizontally technologies Co., ltd.) with a notch of 2mm.

Elongation at break, tensile strength/tensile modulus and flexural strength/flexural modulus were measured by an electronic universal tester (UTM 4204X, shenzhen , vertically and horizontally technologies Co., ltd., china) at a tensile speed of 50mm/min and a flexural pressing speed of 2mm/min.

Example 1

This example is intended to illustrate a PLA/PCL composite material made using the method of the invention.

FIG. 5 is a schematic block diagram of a process flow of the PLA/PCL composite material and the PLA/PCL product of the invention, and using the pulse positive stress extruder of FIG. 1, using the extrusion system of the pulse positive stress extruder of FIG. 2, according to the pulse positive stress processing principle of the pulse positive stress extruder of FIG. 3; the preparation steps of the PLA/PCL composite material are as follows:

Step (1): selecting PLA with weight average molecular weight of 100000g/mol and PCL with weight average molecular weight of 30000g/mol, wherein the viscosity of PLA is 3 times of that of PCL, and mixing PLA and PCL according to mass ratio of 8:2, uniformly mixing in a high-speed mixer to obtain a PLA and PCL mixture;

Step (2): setting the temperature of the extruder under the action of pulse positive stress from a feed inlet to a die head to be 100 , 120 , 140 , 150 and 165 respectively, and setting the rotating speed of a rotor to be 50rpm; when the motor works, the rotor reversely revolves around the axis of the inner cavity of the stator by taking the eccentric quantity e as a radius while rotating under the drive of the power speed reducing distributor, and the revolution speed is 4 times of the rotation speed of the rotor; wherein e is 5mm;

Step (3): adding the PLA and PCL mixture into an extruder with a pulse positive stress effect, and melting, plasticizing, mixing and transporting the material in the extruder from a feeding area to a discharge hole under the pulse positive stress effect of 0.6MPa (spiral section), 2.5MPa (straight section), 3.5MPa (spiral section), 5.5MPa (straight section), 4.5MPa (spiral section), 10.5MPa (straight section) and 7.2MPa (spiral section) on the material in a spiral section and a straight section to obtain the PLA/PCL composite material with in-situ fiber formation, good compatibility and excellent performance, wherein the internal microstructure is shown in figure 4; the structural parameters of the PLA/PCL composite are shown in Table 1.

As can be seen from FIG. 4, PLA with larger apparent viscosity is coated by PCL phase with relatively lower apparent viscosity in the process of mixing by the action of positive pulse stress in the process of extruding by a spiral section, and further, in the process of extruding by a flat section, the two phases are further uniformly dispersed under the traction of positive stress, so that the PLA/PCL composite material with a core-shell structure is finally obtained, the diameter of the core (PLA) is 2+/-0.3 mu m, the diameter of the shell (PCL) is 5+/-0.5 mu m, the PCL with relatively good mechanical property is continuously distributed among PLA cores, and the beneficial structural support is provided for improving the mechanical strength of the PLA/PCL composite material.

Step (4): the PLA/PCL composite material prepared by the double-screw extruder was put into a press vulcanizer for molding, the temperature of the press vulcanizer was set to 180 , the press was exhausted 10 times, the stroke was 1.5mm, the pressure was 20MPa, and dumbbell-shaped test samples were prepared, and the mechanical properties were tested, and the test results are shown in Table 2.

Example 2

A PLA/PCL composite was prepared in the same manner as in example 1, except that:

In the step (1), PLA with a weight average molecular weight of 100000g/mol and PCL with a molecular weight of 30000g/mol is selected, and PLA and PCL raw materials are mixed according to a mass ratio of 9:1, uniformly mixing in a high-speed mixer to obtain a PLA and PCL mixture;

In the step (2), the temperature of the extruder under the action of the pulse positive stress from the feed inlet to the die head is respectively set to be 100 , 120 , 140 , 150 and 165 , and the rotating speed of the rotor is set to be 50rpm;

In the step (3), the PLA and PCL mixture is added into an extruder with the effect of pulse normal stress, and the extruder melts, plasticizes, mixes, transports and extrudes the materials under the effect of the pulse normal stress of 0.6MPa (spiral section), 2.5MPa (straight section), 3.5MPa (spiral section), 5.5MPa (straight section), 4.5MPa (spiral section), 10.5MPa (straight section) and 7.2MPa (spiral section) respectively from a feeding area to a discharge hole, so as to obtain the PLA/PCL composite material with in-situ fiber formation, good compatibility and excellent performance.

PLA/PCL composite materials are prepared, and the structural parameters of the PLA/PCL composite materials are shown in Table 1.

And preparing a PLA/PCL product by using the PLA/PCL composite material, and carrying out mechanical property test on the PLA/PCL product, wherein the test result is shown in table 2.

Example 3

A PLA/PCL composite was prepared in the same manner as in example 1, except that: in the step (1), PLA with weight average molecular weight of 100000g/mol and PCL with weight average molecular weight of 30000g/mol is selected, and PLA and PCL raw materials are mixed according to a mass ratio of 7:3, uniformly mixing in a high-speed mixer to obtain a PLA and PCL mixture;

Setting the temperature of the extruder with positive pulse stress in the step (2) from a feed inlet to a die head to be 100 , 120 , 140 , 150 and 165 respectively, and setting the rotating speed of a rotor to be 50rpm;

Example 4

A PLA/PCL composite was prepared in the same manner as in example 1, except that: in the step (1), PLA with weight average molecular weight of 100000g/mol and PCL with weight average molecular weight of 30000g/mol is selected, and PLA and PCL raw materials are mixed according to a mass ratio of 6:4, uniformly mixing in a high-speed mixer to obtain a PLA and PCL mixture;

In the step (3), the PLA and PCL mixture is added into an extruder with the effect of pulse normal stress, and the extruder melts, plasticizes, mixes, transports and extrudes the materials under the effect of the pulse normal stress of 3.2MPa (spiral section), 8.5MPa (flat section), 4.5MPa (spiral section), 12.5MPa (flat section), 6.5MPa (spiral section), 14.5MPa (flat section) and 7.2MPa (spiral section) respectively from a feeding area to a discharge hole, so as to obtain the PLA/PCL composite material with in-situ fiber formation, good compatibility and excellent performance.

Comparative example 1

The PLA/PCL composite material was prepared by using a twin-screw extruder, and detection analysis was performed, in comparison with the PLA/PCL composite material prepared in example 1 of the present invention.

The preparation method for preparing the PLA/PCL composite material by the double-screw extruder comprises the following steps:

Step (1): PLA and PCL are prepared from the following raw materials in mass ratio of 8:2, uniformly mixing in a high-speed mixer to obtain a PLA and PCL mixture;

Step (2): setting the temperature of the twin-screw extruder from a feed inlet to a die head to be 100 , 120 , 140 , 150 and 165 respectively, and setting the rotating speed of the screws to be 50rpm;

Step (3): adding the PLA and PCL mixture into a double-screw extruder, and melting, plasticizing, mixing, transporting and extruding the materials under the strong shearing action of the extruder to obtain a PLA/PCL composite material; the structural parameters of the PLA/PCL composite are shown in Table 1.

TABLE 1

TABLE 2

Project	Tensile Strength/MPa	Flexural Strength/MPa	Elongation at break/%	Impact strength/MPa
					Example 1	61.6	48.6	158.2	26.2
Example 2	63.2	49.7	119.3	20.5
					Example 3	58.7	46.8	163.3	27.4
Example 4	56.3	44.2	172.8	29.8
					Comparative example 1	48.5	41.5	118.5	20.3

As can be seen from Table 2, the PLA/PCL composite material prepared by the method of the invention in example 1 has improved comprehensive mechanical properties, wherein the tensile strength is improved by 27%, the bending strength is improved by 17%, the elongation at break is improved by 34%, and the impact strength is improved by 29% compared with the PLA/PCL composite material prepared by the double-screw extruder in comparative example 1.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims

1. The PLA/PCL two-phase biopolymer composite material is characterized by comprising a core and a shell coated outside the core, wherein the core is PLA, the shell is PCL, the diameter of the core is 0.8-2.8 mu m, and the diameter of the shell is 2.7-7 mu m.

2. The composite material of claim 1, wherein the weight average molecular weight of PLA is 80000-120000g/mol and the weight average molecular weight of polycaprolactone is 20000-40000g/mol;

and/or, the viscosity of PLA is 2-5 times that of PCL.

3. The preparation method of the PLA/PCL two-phase biopolymer composite material is characterized by comprising the following steps:

s1: uniformly mixing PLA and PCL to obtain a PLA/PCL mixture;

4. The method according to claim 3, wherein the amount of PCL is 10-40 wt.% and the amount of PLA is 60-90 wt.%, based on the total amount of PLA and PCL;

Preferably, the amount of PCL is 20-30 wt.% and the amount of PLA is 70-80 wt.%, based on the total amount of PLA and PCL.

5. The method of manufacturing according to claim 3 or 4, wherein the pulsed positive stress extruder comprises a frame system, a drivetrain, a temperature control system, and an extrusion system;

And/or the rack system comprises a rack (1);

And/or the power transmission system comprises a motor (2), a coupler (3) and a power reduction distributor (4); the output shaft of the motor (2) is connected with the input shaft of the power speed reduction distributor (4) through the coupler (3);

And/or the temperature control system comprises a heating and cooling device, and the heating and cooling device is arranged on the outer side of the stator (7);

And/or the extrusion system comprises a hopper (5), a rotor (6) and a stator (7); the rotor (6) is arranged in the inner cavity of the stator (7) and is connected with the output shaft of the power speed reduction distributor (4); one side of the stator (7) is fixedly connected with the power reduction distributor (4) through a connecting half, and the other side of the stator is supported by a stator support frame; the hopper (6) is arranged at the feed opening of the stator (7).

6. The method of manufacturing according to claim 5, wherein the rotor (6) is of a topology with continuously varying outer surface;

and/or the cross section of the rotor (6) is a curved-edge topological quadrilateral;

And/or the outer surface of the rotor (6) comprises a helical section and a flat section, and the pitch of the helical section gradually decreases in the extrusion direction until reaching the flat section.

7. The preparation method according to claim 5, wherein the stator (7) inner cavity surface is of continuously varying topology;

and/or the cross section of the inner cavity of the stator (7) is a curved Bian Tapu pentagon;

and/or the inner cavity surface of the stator (7) comprises a spiral section and a straight section, and the pitch of the spiral section gradually decreases along the extrusion direction until reaching the straight section;

And/or the spiral section and the straight section structure of the stator (7) are in one-to-one correspondence with the spiral section and the straight section structure of the rotor (6);

and/or the outer topological curved surface of the rotor (6) is meshed with the inner topological curved surface of the inner cavity of the stator (7);

and/or the pitch of each part of the helical section of the stator (7) is 1.25 times the pitch of the corresponding helical section of the rotor (6).

8. The preparation method according to any one of claims 5 to 7, wherein, in operation, the rotor (6) rotates under the drive of the power reduction distributor (4) and reversely revolves around the axis of the inner cavity of the stator (7) with the eccentric e as a radius, and the revolution speed is 4 times of the rotation speed;

And/or the eccentric amount e is 1-8mm.

9. A method of manufacture according to claim 3, wherein the temperature control system is divided in the extrusion direction on the stator (7) into five control zones, each temperature control zone having a temperature in the range 25-300 ;

And/or the rotation speed of the rotor (6) is 0-100rpm.

10. A method of manufacture according to claim 3, wherein the condition of pulsed positive stress comprises: the pressure is 0.1-20MPa;

and/or, the condition of pulsed positive stress comprises: the periodical pressure of the straight section is 2.5-14.5MPa, preferably 2.5-12MPa, and the periodical pressure of the spiral section is 0.5-8MPa;

more preferably, the extruder applies a pulse normal stress of 0.6.+ -. 0.2MPa, 2.5.+ -. 0.3MPa, 3.5.+ -. 0.2MPa, 5.5.+ -. 0.3MPa, 4.5.+ -. 0.4MPa, 10.5.+ -. 0.5MPa and 7.2.+ -. 0.2MPa to the material in the screw section and the flat section from the feeding section to the discharge port, respectively.

11. A PLA/PCL two-phase biopolymer composite prepared by the preparation method of any one of claims 3 to 10.

12. A PLA/PCL article, characterized in that it is prepared from the PLA/PCL two-phase biopolymer composite of any of claims 1-2 and 11.