Rheological test method and application of ultra-high biomass fiber content wood-plastic composites

Abstract

The present invention discloses a rheological test method for a wood-plastic composite material with ultra-high biomass fiber content, comprising: S1, pressing biomass fiber and thermoplastic polymer matrix into sheets respectively; S2, layering the pressed biomass fiber A and thermoplastic polymer matrix B in a combination mode according to a mass ratio; S3, placing the wood-plastic composite material with ultra-high biomass fiber content obtained after superimposed and combined pressing into a rheometer for rheological performance testing. The present invention adopts a stress control method to place the biomass fiber pressed sheet A and the thermoplastic polymer matrix pressed sheet B into a rotational rheometer in a superimposed manner for testing, thereby solving the problem that the traditional rheological test method cannot obtain accurate rheological property data of the wood-plastic composite material with ultra-high biomass fiber content, providing guidance for the research and development and preparation of the wood-plastic composite material with ultra-high biomass fiber content, and solving technical problems such as difficulty in feeding ultra-high content biomass fiber and uneven dispersion.

Description

Technical Field

[0001] The invention relates to a wood-plastic composite material with ultra-high biomass fiber content, and in particular to a rheological testing method of the wood-plastic composite material with ultra-high biomass fiber content and application thereof. Background Art

[0002] As a green and environmentally friendly composite material, wood-plastic composite materials mainly use thermoplastic polymers such as polyethylene, polypropylene and polyvinyl chloride, mixed with a certain content (5-70wt%) of wood, bamboo, straw and other lignified plant fiber materials, and then formed by extrusion, molding, injection molding, etc. Wood-plastic composite materials have developed rapidly at home and abroad in recent decades and are widely used in interior decoration, outdoor gardening, construction, transportation, packaging and other fields. Since the price of biomass fiber materials is only one-tenth of thermoplastic polymers or even lower, increasing the content of cheap biomass fibers in the wood-plastic composite system can not only improve the woodiness of the surface of the wood-plastic composite material, but also significantly reduce the manufacturing cost of the wood-plastic composite material to improve its market competitiveness.

[0003] Increasing the wood fiber content to 80-95wt% or even higher can not only reduce the amount of polymer (petrochemical resources), but also further improve the utilization rate of agricultural and forestry biomass resources, which is in line with the sustainable development concept of "Green water and green mountains are gold and silver mountains". However, because the presence of ultra-high content of biomass fiber will cause the viscosity of wood-plastic melt to increase sharply, extrusion distortion and melt fracture are prone to occur, and molding processing is difficult. Ultra-high biomass fiber content will bring a series of problems: uneven raw material mixing, poor melt fluidity, increased viscosity, and molding difficulties. In addition, a large number of biomass fibers with low bulk density form bridges, which lead to feeding difficulties and uneven dispersion in the wood-plastic matrix. The above problems will directly affect the production efficiency and quality of the product, and these problems are closely related to the processing characteristics of ultra-high-filled wood-plastic composites, that is, the rheological properties of the melt. The rheological properties of the melt can reveal the flow law and explain the causes of these problems. Therefore, mastering the rheological properties of ultra-high-filled wood-plastic composites has important theoretical guidance and application value for its processing and molding and improving product quality. Through the study of WPC rheology, we can obtain viscoelastic information directly related to the system, and this information will directly reflect the influence mechanism of the formulation composition, processing parameters and equipment on the WPC system. Therefore, the rheological study of WPC is crucial to the actual processing production and equipment improvement.

[0004] The commonly used rheological test methods are not suitable for rheological properties testing of ultra-high-filled wood-plastic composites: rotational rheological tests are only suitable for systems with a biomass fiber content of less than 60wt%; capillary rheological test methods require that the biomass fiber content cannot exceed 30wt%, and high content or large-size biomass fibers may damage the instrument or inaccurate test data; torque rheological tests usually require that the biomass fiber content does not exceed 80wt%, otherwise wall slip and other phenomena will occur, limiting the accuracy of the test. When the biomass fiber content exceeds 70wt%, the melt rheological properties of the wood-plastic composite material change from liquid-like to solid-like, the fluidity becomes worse, and the structure becomes more complex. It is difficult for conventional rheological test instruments to obtain accurate rheological information data such as viscosity, modulus, and damping. The inability to collect effective data during the rheological test limits the research and development and preparation of ultra-high-filled wood-plastic composites. Therefore, developing a test method that can accurately obtain rheological property data of ultra-high-filled wood-plastic composites is the key to the research and development and preparation of ultra-high-filled wood-plastic composites. Summary of the invention

[0005] The main purpose of the present invention is to address the deficiencies of the prior art and propose a rheological testing method for ultra-high biomass fiber content wood-plastic composite materials. The rheological property data of the ultra-high filling wood-plastic composite materials tested by this method can play an important role in the research and development and preparation of ultra-high filling wood-plastic composite materials.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides:

[0008] A rheological testing method for a wood-plastic composite material with ultra-high biomass fiber content comprises the following steps:

[0009] S1, pressing the biomass fiber and the thermoplastic polymer matrix into sheets respectively;

[0010] S2, layering and stacking the pressed biomass fiber A and the thermoplastic polymer matrix B in a combination mode according to a mass ratio to obtain a wood-plastic composite material with an ultra-high biomass fiber content;

[0011] S3. Put the ultra-high biomass fiber content wood-plastic composite material obtained by stacking and pressing into a rheometer for rheological property testing.

[0012] In some embodiments of the present invention, in steps S2 and S3, the mass fraction of the biomass fiber content in the ultra-high biomass fiber content wood-plastic composite material is 80-95wt%.

[0013] In some embodiments of the present invention, in step S1, the tableting process of the biomass fiber and the thermoplastic polymer matrix is: temperature 120-200°C, pressure 1-15 MPa, time 3-20 min; the density of the biomass fiber after tableting is 0.1-0.9 g / cm 3 The thermoplastic polymer matrix density is 0.9 to 1.2 g / cm 3 ; The tabletting equipment is a flat vulcanizing press.

[0014] In some embodiments of the present invention, in step S2, the stacking combination of the pressed biomass fiber A and the thermoplastic polymer matrix B is at least one of A / B, B / A, A / B / A, and B / A / B; the mass ratio of the pressed biomass fiber A to the thermoplastic polymer matrix B is 8:2 to 19:1.

[0015] In some embodiments of the present invention, in steps S1 and S2, the type of biomass fiber is selected from at least one of wood, bamboo, and straw; and the size of the biomass fiber is 20-100 meshes.

[0016] In some embodiments of the present invention, in steps S1 and S2, the thermoplastic polymer matrix is ​​composed of a thermoplastic plastic and an appropriate amount of an additive; the thermoplastic plastic is a new thermoplastic polymer material or a recycled thermoplastic polymer material, selected from at least one of polyethylene, polypropylene, polyvinyl chloride and polystyrene; and / or

[0017] The auxiliary agent includes an interfacial compatibility agent and a lubricant, wherein:

[0018] The interfacial compatibilizer is selected from at least one of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, maleic anhydride grafted polystyrene, glycidyl methacrylate grafted polyethylene, glycidyl methacrylate grafted polypropylene, glycidyl methacrylate grafted polystyrene, titanate, isocyanate, aminosilane, vinyl silane, and methacryloxysilane; and / or

[0019] The lubricant is selected from at least one of paraffin wax, polyethylene wax, stearic acid, stearic acid metal salt, and ethylene acrylic acid copolymer metal salt.

[0020] In some embodiments of the present invention, in step S3, the rheometer is a rotational rheometer, and the fixture used is a non-slip flat fixture with a diameter of 25 mm.

[0021] In some embodiments of the present invention, in step S3, the axial force of the rotational rheometer is set to 1-10N, and the temperature is set to 160-200°C.

[0022] In some embodiments of the present invention, the test mode of the rotational rheometer is at least one of temperature scanning, time scanning, and frequency scanning.

[0023] The second aspect of the present invention provides:

[0024] The above-mentioned rheological test method for ultra-high biomass fiber content wood-plastic composite materials is used to simulate the rheological behavior of ultra-high biomass fiber content wood-plastic composite materials during extrusion or hot pressing.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention heat-presses biomass fiber A and thermoplastic polymer matrix B into sheets by a flat vulcanizer, and then stacks the biomass fiber sheet A and the thermoplastic polymer matrix sheet B in different combinations to perform rheological property testing using a rotational rheometer, that is, the biomass fiber and the thermoplastic polymer matrix are formed in the first sheeting process, and the problem of fragile dispersion of the raw materials is avoided in the formed biomass fiber and the thermoplastic polymer matrix; and the second combination stacking process can simulate the rheological behavior of the ultra-high biomass fiber content wood-plastic composite material extrusion or hot pressing processing. In addition, the rheological properties of the pressed sheets after being stacked and combined in different ways are tested by a rotational rheometer using a non-slip flat fixture with a diameter of 25 mm. At least one test mode of temperature scanning, time scanning and frequency scanning is used for testing, so that accurate rheological property data of the ultra-high filling wood-plastic composite material can be obtained, which largely solves the problem that the traditional rheological test method cannot obtain the rheological property data of the ultra-high filling wood-plastic composite material; the rheological property data obtained by analyzing the test method of the present invention is helpful to further study the research and development and preparation of high-filling wood-plastic composite materials, solve the problems of feeding difficulties, uneven dispersion of wood-plastic matrix, and molding difficulties in the preparation process of high-filling wood-plastic composite materials, and finally provide important theoretical guidance and application value for the processing and molding of high-filling wood-plastic composite materials and improving product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 These are the rheological properties test results of the ultra-high biomass fiber content wood-plastic composite material in Example 1 of the present invention.

[0028] Figure 2 These are the rheological property test results of the ultra-high biomass fiber content wood-plastic composite material in Example 2 of the present invention.

[0029] Figure 3 These are the rheological properties test results of the ultra-high biomass fiber content wood-plastic composite material in Example 3 of the present invention.

[0030] Figure 4These are the rheological property test results of the ultra-high biomass fiber content wood-plastic composite material in Example 4 of the present invention.

[0031] Figure 5 The rheological properties test results of the ultra-high biomass fiber content wood-plastic composite material in Comparative Example 1 of the present invention are shown.

[0032] Figure 6 Schematic diagram of the rheological behavior of ultra-high biomass fiber content wood-plastic composite material simulated by a rotational rheometer in an embodiment of the present invention.

[0033] Reference numerals:

[0034] 1- Linear low density polyethylene (LLDPE) tablets;

[0035] 2- Poplar fiber sheets. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0037] Illustratively, in the following examples, the instrument used is a rotational rheometer, the fixture is a non-slip flat fixture with a diameter of 25 mm, the test method is a stress control method, the torque is controlled between 1 and 10N, the temperature is controlled between 160 and 200°C, and a scanning test is performed on the superimposed and combined samples.

[0038] Example 1

[0039] A rheological testing method for a wood-plastic composite material with ultra-high biomass fiber content comprises the following steps:

[0040] S1. Press the poplar fiber into sheets using a flat vulcanizer at a temperature of 170°C and a pressure of 9 MPa for 7 minutes; at the same time, press the linear low-density polyethylene (LLDPE) into sheets using a flat vulcanizer at a temperature of 140°C and a pressure of 5 MPa for 5 minutes;

[0041] S2, layering and stacking the pressed poplar fiber and LLDPE in a mass ratio of 8:2; the combination method is LLDPE / poplar fiber to obtain a wood-plastic composite material with ultra-high biomass fiber content;

[0042] S3. After the temperature of the rotational rheometer is raised to 180°C, the ultra-high biomass fiber content wood-plastic composite material obtained by stacking and pressing is placed in a flat plate fixture with a diameter of 25 mm of the rheometer, with an axial force of 5N, and temperature and time scanning is performed to simulate the processing rheological behavior of the ultra-high biomass fiber content wood-plastic composite material.

[0043] The rheological properties test results of the ultra-high biomass fiber content wood-plastic composites obtained after superimposed combined tableting are as follows: Figure 1 This figure shows the frequency of the storage modulus and complex viscosity of the poplar fiber and LLDPE superimposed and pressed into sheets at a mass ratio of 8:2 to simulate the 80wt% biomass fiber content wood plastic system. ω Dependence. Compared with the high-frequency region, the difference in rheological parameters in the low-frequency region is more obvious. This is because the low-frequency region characterizes the movement of polymer molecular chains and long chain segments, while the high-frequency region is the movement of short chain segments. The frequency dependence of the storage modulus of the 80wt% wood-plastic system is weakened, and it exhibits obvious solid-like rheological behavior in the low-frequency region. The appearance of solid-like rheological behavior indicates that the long-term movement of macromolecular motion units is restricted, and this restriction originates from the formation of ultra-high content biomass fiber network structure in the system. The complex viscosity of 80wt% wood-plastic decreases significantly with increasing frequency, showing significant shear-thinning non-Newtonian behavior. Figure 1 The rheological data results can effectively explain the rheological laws of 80wt% wood-plastic system.

[0044] Example 2

[0045] A rheological testing method for a wood-plastic composite material with ultra-high biomass fiber content comprises the following steps:

[0046] S1. Press the poplar fiber into sheets using a flat vulcanizer at a temperature of 170°C and a pressure of 9 MPa for 7 minutes; at the same time, press the linear low-density polyethylene (LLDPE) into sheets using a flat vulcanizer at a temperature of 140°C and a pressure of 5 MPa for 5 minutes;

[0047] S2, layering and stacking the pressed poplar fiber and LLDPE in a mass ratio of 17:3; and combining in a manner of LLDPE / poplar fiber to obtain a wood-plastic composite material with ultra-high biomass fiber content;

[0048] S3. After the temperature of the rotational rheometer is raised to 180°C, the ultra-high biomass fiber content wood-plastic composite material obtained by stacking and combining pressed sheets is placed in a flat plate fixture with a diameter of 25 mm of the rheometer, and the axial force is 5N. The temperature and time scans are performed to simulate the processing rheological behavior of the ultra-high biomass fiber content wood-plastic composite material.

[0049] The rheological properties test results of the ultra-high biomass fiber content wood-plastic composites obtained after superimposed combined tableting are as follows: Figure 2 This figure shows the frequency of the storage modulus and complex viscosity of the poplar fiber and LLDPE superimposed and pressed at a mass ratio of 17:3 to simulate the wood-plastic system with 85wt% biomass fiber content. ω Dependence. Compared with the high-frequency region, the difference in rheological parameters in the low-frequency region is more obvious. This is because the low-frequency region characterizes the movement of polymer molecular chains and long chain segments, while the high-frequency region is the movement of short chain segments. The frequency dependence of the storage modulus of the 85wt% wood-plastic system is weakened, and it exhibits obvious solid-like rheological behavior in the low-frequency region. The appearance of solid-like rheological behavior indicates that the long-term movement of macromolecular motion units is restricted, and this restriction originates from the formation of ultra-high content biomass fiber network structure in the system. The complex viscosity of 85wt% wood-plastic decreases significantly with increasing frequency, showing significant shear-thinning non-Newtonian behavior. Figure 2 The rheological data results can effectively explain the rheological laws of 85wt% wood-plastic system.

[0050] Example 3

[0051] A rheological testing method for a wood-plastic composite material with ultra-high biomass fiber content comprises the following steps:

[0052] S1. Press the poplar fiber into sheets using a flat vulcanizer at a temperature of 170°C and a pressure of 9 MPa for 7 minutes; at the same time, press the linear low-density polyethylene (LLDPE) into sheets using a flat vulcanizer at a temperature of 140°C and a pressure of 5 MPa for 5 minutes;

[0053] S2, layering and stacking the pressed poplar fiber and LLDPE in a mass ratio of 9:1; and combining in a manner of LLDPE / poplar fiber to obtain a wood-plastic composite material with ultra-high biomass fiber content;

[0054] S3. After the temperature of the rotational rheometer is raised to 180°C, the ultra-high biomass fiber content wood-plastic composite material obtained by stacking and combining pressed sheets is placed in a flat plate fixture with a diameter of 25 mm of the rheometer, and the axial force is 5N. The temperature and time scans are performed to simulate the processing rheological behavior of the ultra-high biomass fiber content wood-plastic composite material.

[0055] The rheological properties test results of the ultra-high biomass fiber content wood-plastic composites obtained after superimposed combined tableting are as follows: Figure 3 This figure shows the frequency of the storage modulus and complex viscosity of the poplar fiber and LLDPE superimposed and pressed at a mass ratio of 9:1 to simulate the wood plastic system with a 90wt% biomass fiber content. ωDependence. Compared with the high-frequency region, the difference in rheological parameters in the low-frequency region is more obvious. This is because the low-frequency region characterizes the movement of polymer molecular chains and long chain segments, while the high-frequency region is the movement of short chain segments. The storage modulus of the 90wt% wood-plastic system has a weakened dependence on frequency, and exhibits obvious solid-like rheological behavior in the low-frequency region. The appearance of solid-like rheological behavior indicates that the long-term movement of macromolecular motion units is restricted, and this restriction stems from the formation of an ultra-high content biomass fiber network structure in the system. The complex viscosity of 90wt% wood-plastic decreases significantly with increasing frequency, showing significant shear-thinning non-Newtonian behavior. Figure 3 The rheological data results can effectively explain the rheological laws of 90wt% wood-plastic system.

[0056] Example 4

[0057] A rheological testing method for a wood-plastic composite material with ultra-high biomass fiber content comprises the following steps:

[0058] S1. Press the poplar fiber into sheets using a flat vulcanizer at a temperature of 170°C and a pressure of 9 MPa for 7 minutes; at the same time, press the linear low-density polyethylene (LLDPE) into sheets using a flat vulcanizer at a temperature of 140°C and a pressure of 5 MPa for 5 minutes;

[0059] S2, layering and stacking the pressed poplar fiber and LLDPE in a mass ratio of 19:1; and combining in a manner of LLDPE / poplar fiber to obtain a wood-plastic composite material with ultra-high biomass fiber content;

[0060] S3. After the temperature of the rotational rheometer is raised to 180°C, the ultra-high biomass fiber content wood-plastic composite material obtained by stacking and combining pressed sheets is placed in a flat plate fixture with a diameter of 25 mm of the rheometer, and the axial force is 5N. The temperature and time scans are performed to simulate the processing rheological behavior of the ultra-high biomass fiber content wood-plastic composite material.

[0061] The rheological properties test results of the ultra-high biomass fiber content wood-plastic composites obtained after superimposed combined tableting are as follows: Figure 4 This figure shows the frequency of the storage modulus and complex viscosity of the poplar fiber and LLDPE superimposed and pressed at a mass ratio of 19:1 to simulate the wood plastic system with a 95wt% biomass fiber content. ωDependence. Compared with the high-frequency region, the difference in rheological parameters in the low-frequency region is more obvious. This is because the low-frequency region characterizes the movement of polymer molecular chains and long chain segments, while the high-frequency region is the movement of short chain segments. The storage modulus of the 95wt% wood-plastic system is less dependent on frequency, and it exhibits obvious solid-like rheological behavior in the low-frequency region. The appearance of solid-like rheological behavior indicates that the long-term movement of macromolecular motion units is restricted, and this restriction originates from the formation of an ultra-high content biomass fiber network structure in the system. The complex viscosity of the 95wt% wood-plastic decreases significantly with increasing frequency, showing significant shear-thinning non-Newtonian behavior. Figure 4 The rheological data results can effectively explain the rheological laws of 95wt% wood-plastic system.

[0062] Comparative Example 1

[0063] A rheological testing method for a wood-plastic composite material with ultra-high biomass fiber content comprises the following steps:

[0064] S1. Mixing 80 wt% of poplar fiber and 20 wt% of LLDPE by a mixer;

[0065] S2. After the above components are fully mixed, they are melt-granulated by a twin-screw extruder to obtain ultra-high-filled wood-plastic pellets with a mass fraction of 80wt% poplar fiber content;

[0066] S3, extruding or hot pressing the ultra-high filling wood-plastic granules to obtain a wood-plastic composite material with a mass fraction of 80wt% poplar fiber content.

[0067] The obtained wood-plastic composite material with a mass fraction of 80wt% poplar fiber content was subjected to temperature and time scanning tests in a rotational rheometer. The data showed a discrete phenomenon and it was impossible to obtain more accurate rheological property data. The rheological performance test results are as follows: Figure 5 This figure shows the storage modulus and complex viscosity frequency of the wood-plastic system with 80wt% biomass fiber content after hot pressing when the mass ratio of poplar fiber and LLDPE is 8:2. ω The data of storage modulus and complex viscosity show obvious discreteness in the low-frequency region, indicating that when the 80wt% biomass fiber content wood-plastic system is directly tested by a rotational rheometer, effective rheological data cannot be accurately obtained due to the wall slip phenomenon between the sample and the fixture surface. Therefore, the traditional rheological test method is no longer applicable to the 80wt% biomass fiber content wood-plastic system.

[0068] Comparative Example 2

[0069] A rheological testing method for a wood-plastic composite material with ultra-high biomass fiber content comprises the following steps:

[0070] S1. Mixing 85 wt% of poplar fiber and 15 wt% of LLDPE by a mixer;

[0071] S2, after the above components are fully mixed, a twin-screw extruder is used for melt granulation to obtain ultra-high filling wood-plastic pellets with a mass fraction of 85wt% poplar fiber content;

[0072] S3. The wood-plastic granules are hot-pressed to obtain a wood-plastic composite material having a mass fraction of 85 wt % poplar fiber content, while extrusion molding failed to successfully obtain a wood-plastic composite material having a mass fraction of 85 wt % poplar fiber content.

[0073] The obtained wood-plastic composite material with a mass fraction of 85wt% poplar fiber content was subjected to temperature and time scanning in a rotational rheometer. The sample showed wall slip phenomenon and accurate rheological property data could not be obtained.

[0074] Comparative Example 3

[0075] A rheological testing method for a wood-plastic composite material with ultra-high biomass fiber content comprises the following steps:

[0076] S1. Mixing 90 wt% of poplar fiber and 10 wt% of LLDPE by a mixer;

[0077] S2. After the above components are fully mixed, a twin-screw extruder is used for melt granulation. Due to feeding difficulties and poplar fiber agglomeration, ultra-high filling wood-plastic pellets with a mass fraction of 90wt% poplar fiber content cannot be obtained.

[0078] Performance Testing

[0079] To better illustrate the present invention, the performance of the ultra-high biomass fiber content wood-plastic composite materials obtained in Examples 1 to 4 and the wood-plastic composite material obtained in Comparative Example 1 is tested. The performance test results are shown in FIG. Figures 1 to 5 shown.

[0080] from Figures 1 to 5 It can be seen from the experimental data that the ultra-high biomass fiber content wood-plastic composite materials of Examples 1 to 4 of the present invention can achieve the rheological property test of the ultra-high biomass fiber content wood-plastic composite materials, and the test obtains accurate rheological property data.

[0081] The above embodiments of the present invention are only examples for explaining the present invention, and are not intended to limit the specific implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above examples. It is impossible to give detailed examples of all implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A rheological test method for ultra-high biomass fiber content wood-plastic composites, It is characterized in that The following steps are involved: S1, pressing the biomass fiber and the thermoplastic polymer matrix into sheets respectively; S2. Layering and stacking the pressed biomass fiber A and the thermoplastic polymer matrix B in a combination of mass ratios to obtain a wood-plastic composite material with ultra-high biomass fiber content, wherein the stacking combination of the pressed biomass fiber A and the thermoplastic polymer matrix B is at least one of A / B, B / A, A / B / A, and B / A / B; and the mass ratio of the pressed biomass fiber A to the thermoplastic polymer matrix B is 8:2 to 19:1; S3, placing the ultra-high biomass fiber content wood-plastic composite material obtained by stacking and pressing into a rotational rheometer for rheological property testing; In steps S2 and S3, the mass fraction of the biomass fiber content in the ultra-high biomass fiber content wood-plastic composite material is 80-95wt%.

2. The test method according to claim 1, Features: In step S1, the biomass fiber and the thermoplastic polymer matrix are pressed at a temperature of 120 to 200°C, a pressure of 1 to 15 MPa, and a time of 3 to 20 min; the density of the biomass fiber after pressing is 0.1 to 0.9 g / cm 3 The thermoplastic polymer matrix density is 0.9 to 1.2 g / cm 3 ; The tabletting equipment is a flat vulcanizing press.

3. The testing method according to claim 1, Features: In steps S1 and S2, the type of biomass fiber is selected from at least one of wood, bamboo, and straw; and the size of the biomass fiber is 20 to 100 meshes.

4. The test method according to claim 1 or 2, Features: In steps S1 and S2, the thermoplastic polymer matrix is ​​composed of thermoplastic plastic and an appropriate amount of additives; the thermoplastic plastic is a new thermoplastic polymer material or a recycled thermoplastic polymer material, selected from at least one of polyethylene, polypropylene, polyvinyl chloride and polystyrene; and / or The auxiliary agent includes an interfacial compatibility agent and a lubricant, wherein: The interfacial compatibilizer is selected from at least one of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, maleic anhydride grafted polystyrene, glycidyl methacrylate grafted polyethylene, glycidyl methacrylate grafted polypropylene, glycidyl methacrylate grafted polystyrene, titanate, isocyanate, aminosilane, vinylsilane, and methacryloxysilane; and / or The lubricant is selected from at least one of paraffin wax, polyethylene wax, stearic acid, stearic acid metal salt, and ethylene acrylic acid copolymer metal salt.

5. The testing method according to claim 1, Features: In step S3, the fixture used in the rotational rheometer is a non-slip flat fixture with a diameter of 25 mm.

6. The testing method according to claim 1, Features: In step S3, the axial force of the rotational rheometer is set to 1-10N, and the temperature is set to 160-200°C.

7. The test method according to claim 6, Features: The test mode of the rotational rheometer is at least one of temperature scanning, time scanning and frequency scanning.

8. Application of the test method according to any one of claims 1 to 7 in simulating the rheological behavior of ultra-high biomass fiber content wood-plastic composite materials during extrusion or hot pressing.

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