CN110936515B - A kind of preparation method of thermoplastic plant fiber prepreg - Google Patents

Abstract

The invention provides a preparation method of a thermoplastic plant fiber prepreg, which comprises the following steps: preparing a fiber material and a thermoplastic polymer matrix, preparing a plate structure, plane or linear pre-formed product, and carrying out heat treatment to obtain the thermoplastic plant fiber pre-impregnated material. The thermoplastic plant fiber prepreg has the advantages that the raw materials are environment-friendly; the continuity of the fiber material is ensured by using the plant fiber material or the bamboo skin as the fiber material; by selecting proper heat treatment temperature and pressure and fusing and combining the fiber material and the thermoplastic polymer matrix, the prepared thermoplastic plant fiber prepreg has high bonding strength, is not easy to separate, has stable performance and strong toughness, and is not easy to break.

Description

A kind of preparation method of thermoplastic plant fiber prepreg

technical field

The invention belongs to the technical field of prepregs, and in particular relates to a preparation method of thermoplastic plant fiber prepregs.

Background technique

Prepreg is an intermediate material for manufacturing high-performance composite materials. It has the advantages of smooth surface, good plasticity, stable resin content, and small thickness and dimension deviation.

Traditional thermosetting fiber composites have problems such as brittle failure, difficult maintenance and repair, and high energy consumption for recycling and scrapping.

The existing glass fiber and carbon fiber thermoplastic prepregs have high product costs, are difficult to recycle, are difficult to degrade, have low material recycling rates, and have increasingly prominent problems such as high equipment requirements. Plant fiber reinforced prepregs are light, high-strength, and low-cost. , Recyclable, easy to degrade, easy to reprocess and so on.

However, due to the certain heterogeneity of the plant fiber itself, the fiber strength is not high, the length is short, and the bonding strength between the fiber and the matrix is poor, how to process it into a continuous and uniform prepreg so that it can meet the required mechanical properties and resin content. And other parameters, to ensure its stable performance is the problem that needs to be solved at present.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing thermoplastic plant fiber prepreg in view of the deficiencies in the prior art. It can be used again for the preparation of thermoplastic plant fiber prepreg, the raw material has a high reusability rate, and is easier to degrade after being discarded. Using plant fiber materials or using bamboo strips as fiber materials can solve the problems of plant fiber itself with certain heterogeneity, low fiber strength and short length, and ensure the continuity of fiber materials; by selecting appropriate heat treatment temperature and pressure, The additive penetrates into the gap between the fiber material and the thermoplastic polymer matrix, and the fiber material and the thermoplastic polymer matrix are melt-bonded. The prepared thermoplastic plant fiber prepreg has high bonding strength and is not easy to separate, and the fiber material is a continuous and uniform material. The prepared The thermoplastic plant fiber prepreg has stable performance, strong toughness, is not easy to break, and can meet the length requirements of different application conditions.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a kind of preparation method of thermoplastic plant fiber prepreg, this method is:

S1, the preparation of fiber material, described fiber material comprises plant fiber material and bamboo strip:

The specific preparation process of the plant fiber material: after soaking the bast part, stem part or leaves or seeds of the plant in water for 0h to 48h, mechanical rolling, fiber opening and drying, the plant fiber is obtained, and the plant fiber is Splicing, braiding and twisting to obtain plant fiber materials;

The specific preparation process of bamboo strips is as follows: sawing off the bamboo, flattening the bamboo joints, opening the bamboo joints from the inside of the bamboo, splitting them into bamboo strips, removing the inner and outer joints, cutting and drying to obtain bamboo strips;

S2, preparation of thermoplastic polymer matrix:

When the thermoplastic matrix is a thermoplastic matrix sheet or thermoplastic matrix tape, after the thermoplastic matrix is modified by adding additives and blending, it is heated at a temperature of 120°C to 350°C and a pressure of 0.1MPa to 0.5MPa. Press to obtain a thermoplastic polymer matrix;

When the thermoplastic thermoplastic matrix is a powder material, the thermoplastic polymer matrix is obtained by adding additives, blending and modifying the thermoplastic matrix;

The thermoplastic matrix is one or both of polyethylene thermoplastic matrix, polypropylene thermoplastic matrix or polyamide thermoplastic matrix;

S3, the preparation of pre-finished products:

The plant fiber material obtained in S1 is used to pave at least one layer of fiber layer on the thermoplastic polymer matrix obtained in S2, and then the thermoplastic polymer matrix is arranged on the fiber layer to form a pre-product of the board structure; the fiber layer When the number of paving layers is multi-layer, 0 ° ~ 90 ° paving is used between each layer; the thermoplastic polymer matrix is a thermoplastic polymer plate;

Or mix the bamboo strips obtained in S1 with the thermoplastic polymer matrix obtained in S2 to obtain a planar preform; the thermoplastic polymer matrix is a thermoplastic polymer tape;

Or adsorb the thermoplastic polymer matrix obtained in S2 to the surface of the plant fiber material obtained in S1 to obtain a linear preform; the thermoplastic polymer matrix is a powder material with a particle size of 198 μm to 350 μm;

S4. Heat-treat the pre-finished product obtained in S3 at a temperature of 120°C to 350°C and a pressure of 0.1MPa to 9MPa for 0.5min to 3min, and after thickness setting, cooling and winding, a thermoplastic plant fiber prepreg is obtained material;

When the thermoplastic matrix in the preform is polyethylene, the heat treatment temperature is 120°C to 180°C;

When the thermoplastic matrix in the preform is polypropylene, the heat treatment temperature is 150°C to 180°C;

When the thermoplastic matrix in the preform is polyamide, the heat treatment temperature is 170°C-350°C.

Preferably, the water content of the fiber material in S1 is ≤12%.

Preferably, the auxiliary agents described in S2 are more than one of modifiers, compatibilizers or functional agents; the modifiers are more than one of thermoplastic acrylic resin and silane coupling agent; the compatibilizer The agent is more than one of maleic anhydride grafted polypropylene and polyvinyl alcohol; the functional agent is more than one of antioxidant, ultraviolet absorber, light stabilizer, environment-friendly flame retardant and cooling masterbatch.

Preferably, the mass fraction of the plant fibers in the thermoplastic plant fiber prepreg in S4 is 5%-70%.

Compared with the prior art, the present invention has the following advantages:

1. The raw material of the plastic plant fiber prepreg prepared by the present invention is environmentally friendly, and the plant fiber comes from a wide range of sources and the cost is low. After use, it can be used again for the preparation of thermoplastic plant fiber prepreg. The raw material has a high reusability rate and is easier to degrade after being discarded.

2. The present invention can solve the problems that the plant fiber itself has certain heterogeneity, the fiber strength is not high, and the length is short by using the plant fiber material or bamboo strips as the fiber material, so as to ensure the continuity of the fiber material; by selecting suitable heat treatment Temperature and pressure, the additive penetrates into the gap between the fiber material and the thermoplastic polymer matrix, the fiber material and the thermoplastic polymer matrix are melted and bonded, the prepared thermoplastic plant fiber prepreg has high bonding strength, is not easy to separate, and the fiber material is continuous and uniform Material, the prepared thermoplastic plant fiber prepreg has stable performance, strong toughness, is not easy to break, and can meet the length requirements of different application conditions.

The present invention is described in further detail below in conjunction with embodiment.

detailed description

Example 1

The preparation method of the thermoplastic plant fiber prepreg of the present embodiment, the method is:

S1, the preparation of fiber material, described fiber material is plant fiber material:

The specific preparation process of the plant fiber material: the stalks of the plants are sequentially pretreated and soaked in water for 24 hours, mechanically rolled, fiber opened and dried to obtain plant fibers with a water content of ≤12%, and the plant fibers are Connecting, braiding, and twisting to obtain plant fiber threads as plant fiber materials; the plants are grasses;

S2, preparation of thermoplastic polymer matrix:

After blending and modifying the thermoplastic matrix by adding additives, the thermoplastic polymer matrix is obtained by hot pressing at a temperature of 120°C and a pressure of 0.5 MPa; the additive is a modifier thermoplastic acrylic resin; the thermal The plastic thermoplastic matrix is a thermoplastic matrix sheet;

S3, the preparation of pre-finished products:

The plant fiber material obtained in S1 is used to pave a layer of fiber layer on the thermoplastic polymer matrix obtained in S2, and then the thermoplastic polymer matrix is arranged on the fiber layer to form a pre-finished product of the board structure; the thermoplastic polymer The substrate is a thermoplastic polymer sheet;

S4. Heat-treat the pre-finished product obtained in S3 for 3 minutes at a temperature of 120° C. and a pressure of 9 MPa. After setting the thickness, cooling, and winding, obtain a thermoplastic plant fiber prepreg with a mass fraction of plant fiber of 5%. material.

The thermoplastic plant fiber prepreg obtained in this example is plate-like, with a density of 0.93g/cm ³ , a tensile strength of 30MPa, a tensile modulus of 2800Mpa, an elongation at break of 2.5%, and a bending strength of 55MPa. The weight is 3000MPa, and the notched impact strength is 28J/M. The preparation method of this example is simple, has low requirements on the shape of the fiber material, and is suitable for mass production. The prepared prepreg can not only exert its light weight and high strength, but also has high bonding strength, is not easy to separate, has good tensile properties, and has good toughness. advantages, and has the characteristics of recyclable, reusable and easy to degrade.

Example 2

The preparation method of the thermoplastic plant fiber prepreg of the present embodiment, the method is:

S1, the preparation of fiber material, described fiber material is plant fiber material:

The specific preparation process of the plant fiber material: the phloem of the plant is sequentially pretreated, soaked in water for 48 hours, mechanically rolled, fiber opened and dried to obtain plant fibers with a water content of ≤12%, and the plant fibers are lengthened , weaving and twisting to obtain a plant fiber thread as a plant fiber material; the plant is flax; the plant can also be jute, ramie;

S2, preparation of thermoplastic polymer matrix:

After blending and modifying the thermoplastic matrix by adding additives, the thermoplastic polymer matrix is obtained by hot pressing at a temperature of 180°C and a pressure of 0.2 MPa; the additive is a compatibilizer maleic anhydride grafted polypropylene ; The thermoplastic thermoplastic matrix is a thermoplastic matrix sheet;

The compatibilizer can also be a mixture of maleic anhydride grafted polypropylene and polyvinyl alcohol or polyvinyl alcohol;

S3, the preparation of pre-finished products:

The plant fiber material obtained in S1 is used to pave two layers of fiber layers on the thermoplastic polymer matrix obtained in S2, and then the thermoplastic polymer matrix is arranged on the fiber layer to form a pre-finished product of the board structure; the two layers of fiber 0° pavement is adopted between the layers; the thermoplastic polymer matrix is a thermoplastic polymer sheet;

S4. Heat-treat the pre-finished product obtained in S3 for 0.5 min at a temperature of 180° C. and a pressure of 0.1 MPa. After setting the thickness, cooling, and winding, a thermoplastic plant fiber with a mass fraction of plant fiber of 70% is obtained. Prepreg.

The thermoplastic plant fiber prepreg obtained in this example is plate-like, with a density of 1.32g/cm ³ , a tensile strength of 70MPa, a tensile modulus of 6500Mpa, an elongation at break of 1.5%, and a bending strength of 80MPa. The weight is 5500MPa, and the notched impact strength is 60J/M. The preparation method of this example is simple, has low requirements on the shape of the fiber material, and is suitable for mass production. The prepared prepreg can not only exert its light weight and high strength, but also has high bonding strength, is not easy to separate, has good tensile properties, and has good toughness. advantages, and has the characteristics of recyclable, reusable and easy to degrade.

Example 3

The preparation method of the thermoplastic plant fiber prepreg of the present embodiment, the method is:

S1, the preparation of fiber material, described fiber material is plant fiber material:

The specific preparation process of the plant fiber material: after the leaves of the plant are pretreated by mechanical rolling, fiber opening and drying, the plant fibers with a water content of ≤12% are obtained, and the plant fibers are lengthened, braided and twisted , obtain plant fiber thread, as plant fiber material; Described plant is palm; Described plant also can be sisal or banana tree;

S2, preparation of thermoplastic polymer matrix:

After blending and modifying the thermoplastic matrix by adding additives, the thermoplastic polymer matrix is obtained by hot pressing at a temperature of 350°C and a pressure of 0.1 MPa; the additive is a functional agent; the functional agent is an antioxidant Agent KY-1010; the thermoplastic thermoplastic matrix is a thermoplastic matrix plate;

The functional agent can also be one or more of antioxidants, ultraviolet absorbers, light stabilizers, environmentally friendly flame retardants or cooling masterbatches;

S3, the preparation of pre-finished products:

The plant fiber material obtained in S1 is used to pave four layers of fiber layers on the thermoplastic polymer matrix obtained in S2, and then the thermoplastic polymer matrix is arranged on the four layers of fiber layers to form a pre-finished board structure; the four layers 90° pavement is adopted between the fiber layers; the thermoplastic polymer matrix is a thermoplastic polymer sheet;

S4. Heat-treat the pre-finished product obtained in S3 for 3 minutes at a temperature of 150° C. and a pressure of 2.1 MPa. After setting the thickness, cooling, and winding, a thermoplastic plant fiber preform with a mass fraction of plant fibers of 50% is obtained. Dipping material.

The thermoplastic plant fiber prepreg obtained in this example is plate-like, with a density of 1.2g/cm ³ , a tensile strength of 65MPa, a tensile modulus of 5000Mpa, an elongation at break of 2.25%, and a bending strength of 62MPa. The weight is 4250MPa, and the notched impact strength is 45J/M. The preparation method of this example is simple, has low requirements on the shape of the fiber material, and is suitable for mass production. The prepared prepreg can not only exert its light weight and high strength, but also has high bonding strength, is not easy to separate, has good tensile properties, and has good toughness. advantages, and has the characteristics of recyclable, reusable and easy to degrade.

Example 4

The preparation method of the thermoplastic plant fiber prepreg of the present embodiment, the method is:

S1, the preparation of fiber material, described fiber material is plant fiber material:

The specific preparation process of the plant fiber material: the seeds of the plant are soaked in water for 48 hours after pretreatment, mechanical rolling, fiber opening and drying to obtain plant fibers with a water content of ≤12%, and the plant fibers are lengthened , weaving and twisting to obtain a plant fiber thread as a plant fiber material; the plant is cotton;

S2, preparation of thermoplastic polymer matrix:

After blending and modifying the thermoplastic matrix by adding additives, the thermoplastic polymer matrix is obtained by hot pressing at a temperature of 180°C and a pressure of 0.2 MPa; the additives are modifier thermoplastic acrylic resin and silane coupling A mixture of agents; the thermoplastic thermoplastic matrix is a thermoplastic matrix sheet;

S3, the preparation of pre-finished products:

The plant fiber material obtained in S1 is used to pave three layers of fiber layers on the thermoplastic polymer matrix obtained in S2, and then the thermoplastic polymer matrix is arranged on the three layers of fiber layers to form a pre-finished product of the board structure; the three layers 60° pavement is adopted between the fiber layers; the thermoplastic polymer matrix is a thermoplastic polymer sheet;

S4. Heat-treat the pre-finished product obtained in S3 for 2.5 minutes at a temperature of 180° C. and a pressure of 6 MPa. After setting the thickness, cooling, and winding, a thermoplastic plant fiber preform with a mass fraction of plant fibers of 60% is obtained. Dipping material.

The thermoplastic plant fiber prepreg obtained in this example is plate-like, with a density of 1.26g/cm ³ , a tensile strength of 60MPa, a tensile modulus of 4800Mpa, an elongation at break of 2.3%, and a bending strength of 75MPa. The weight is 4600MPa, and the notched impact strength is 56J/M. The preparation method of this example is simple, has low requirements on the shape of the fiber material, and is suitable for mass production. The prepared prepreg can not only exert its light weight and high strength, but also has high bonding strength, is not easy to separate, has good tensile properties, and has good toughness. advantages, and has the characteristics of recyclable, reusable and easy to degrade.

Example 5

The preparation method of the thermoplastic plant fiber prepreg of the present embodiment, the method is:

S1, the preparation of fiber material, described fiber material is bamboo strips:

The specific preparation process of bamboo strips is as follows: sawing off the bamboo, cutting the bamboo joints flat, and then opening the bamboo joints from the inside of the bamboo, splitting them into bamboo strips, removing the inner and outer joints, cutting and drying to obtain bamboo strips with a water content of ≤12% ;

S2, preparation of thermoplastic polymer matrix:

After blending and modifying the thermoplastic matrix by adding additives, the thermoplastic polymer matrix is obtained by hot pressing at a temperature of 200°C and a pressure of 0.3 MPa; the additives are modifiers, silane coupling agents, compatible A mixture of agent maleic anhydride grafted polypropylene and functional agent light stabilizer GW-540; the thermoplastic thermoplastic matrix is a thermoplastic matrix tape;

S3, the preparation of pre-finished products:

Mixing the bamboo strips obtained in S1 with the thermoplastic polymer matrix obtained in S2 to obtain a planar preform; the thermoplastic polymer matrix is a thermoplastic polymer tape;

S4. Heat-treat the pre-finished product obtained in S3 for 1.5 min at a temperature of 170° C. and a pressure of 2 MPa. After setting the thickness, cooling, and winding, a thermoplastic plant fiber pre-form with a mass fraction of plant fibers of 30% is obtained. Dipping material.

The thermoplastic plant fiber prepreg obtained in this example is strip-shaped, with a density of 1.46g/cm ³ , a tensile strength of 100MPa, a tensile modulus of 7000Mpa, an elongation at break of 1.8%, and a bending strength of 90MPa. The weight is 5000MPa, and the impact strength is 50J/m. The preparation method of this example is simple, has low requirements on the shape of the fiber material, and is suitable for mass production. The prepared prepreg can not only exert its light weight and high strength, but also has high bonding strength, is not easy to separate, has good tensile properties, and has good toughness. advantages, and has the characteristics of recyclable, reusable and easy to degrade.

Example 6

The preparation method of the thermoplastic plant fiber prepreg of the present embodiment, the method is:

S1, the preparation of fiber material, described fiber material is bamboo strips:

The specific preparation process of bamboo strips is as follows: sawing off the bamboo, cutting the bamboo joints flat, and then opening the bamboo joints from the inside of the bamboo, splitting them into bamboo strips, removing the inner and outer joints, cutting and drying to obtain bamboo strips with a water content of ≤12% ;

S2, preparation of thermoplastic polymer matrix:

After blending and modifying the thermoplastic matrix by adding additives, the thermoplastic polymer matrix is obtained by hot pressing at a temperature of 200°C and a pressure of 0.5 MPa; the additives are compatibilizer polyvinyl alcohol and functional agent UV absorbing A mixture of UVP-327; the thermoplastic thermoplastic matrix is a thermoplastic matrix tape;

S3, the preparation of pre-finished products:

Mixing the bamboo strips obtained in S1 with the thermoplastic polymer matrix obtained in S2 to obtain a planar preform; the thermoplastic polymer matrix is a thermoplastic polymer tape;

S4. Heat-treat the pre-finished product obtained in S3 for 1 min at a temperature of 180°C and a pressure of 5 MPa. After setting the thickness, cooling, and winding, obtain a thermoplastic plant fiber prepreg with a mass fraction of plant fibers of 40%. material.

The thermoplastic plant fiber prepreg obtained in this example is strip-shaped, with a density of 1.16g/cm ³ , a tensile strength of 95MPa, a tensile modulus of 4200Mpa, an elongation at break of 1.25%, and a bending strength of 100MPa. The weight is 7000MPa, and the notched impact strength is 38J/m. The preparation method of this example is simple, has low requirements on the shape of the fiber material, and is suitable for mass production. The prepared prepreg can not only exert its light weight and high strength, but also has high bonding strength, is not easy to separate, has good tensile properties, and has good toughness. advantages, and has the characteristics of recyclable, reusable and easy to degrade.

Example 7

The preparation method of the thermoplastic plant fiber prepreg of the present embodiment, the method is:

S1, the preparation of fiber material, described fiber material is plant fiber material:

The specific preparation process of the plant fiber material: after soaking the branch sections of the plant in water for 12 hours, mechanically rolling, fiber opening and drying, the plant fiber is obtained, and the plant fiber is lengthened, braided and twisted to obtain plant fiber materials;

S2, preparation of thermoplastic polymer matrix:

After blending and modifying the powdery polyamide thermoplastic matrix with a particle size of 198 μm to 350 μm with additives, a powdery thermoplastic polymer matrix is obtained; the additives are modifier thermoplastic acrylic resin and functional agent environment-friendly barrier A mixture of fuel hydrotalcites;

S3, the preparation of pre-finished products:

The thermoplastic polymer matrix obtained in S2 with a particle size of 198 μm to 350 μm is put into a powder tank, and the plant fiber composite material obtained in S1 is moved forward at a speed of 0.1 m/min, passing through the powder tank, and the plant fiber is composited The thermoplastic polymer matrix is adsorbed on the surface of the material to obtain a linear preform;

S4. Heat-treat the pre-finished product obtained in S3 for 3 minutes at a temperature of 170°C and a pressure of 5 MPa. After setting the thickness, cooling, and winding, obtain a thermoplastic plant fiber prepreg with a mass fraction of plant fibers of 50%. material.

The thermoplastic plant fiber prepreg obtained in this embodiment is linear, with a density of 1.47g/cm ³ , a tensile strength of 160MPa, a tensile modulus of 9000Mpa, an elongation at break of 2.5%, a flexural strength of 220MPa, and a flexural modulus of 9500MPa, the notched impact strength is 210J/m. The preparation method of this example is simple, has low requirements on the shape of the fiber material, and is suitable for mass production. The prepared prepreg can not only exert its light weight and high strength, but also has high bonding strength, is not easy to separate, has good tensile properties, and has good toughness. advantages, and has the characteristics of recyclable, reusable and easy to degrade.

Example 8

The preparation method of the thermoplastic plant fiber prepreg of the present embodiment, the method is:

S1, the preparation of fiber material, described fiber material is plant composite fiber material:

The specific preparation process of plant fiber materials: the stems of plants are soaked in water for 40 hours, mechanically rolled, fiber opened and dried to obtain plant fibers, and the plant fibers are lengthened, braided and twisted to obtain plant fibers. fiber material;

S2, preparation of thermoplastic polymer matrix:

After blending and modifying the powdery polyethylene thermoplastic matrix with a particle size of 198 μm to 350 μm with additives, a powdery thermoplastic polymer matrix is obtained; the additives are modifier silane coupling agent, compatibilizer horse A mixture of toric anhydride grafted polypropylene, functional agent cooling masterbatch and functional agent light stabilizer GW-540;

S3, the preparation of pre-finished products:

Screen the thermoplastic polymer matrix with a particle size of 198 μm to 350 μm obtained in S2 into the powder tank, move the plant fiber composite material obtained in S1 forward at a speed of 3 m/min, pass through the powder tank, and the plant fiber composite material The thermoplastic polymer matrix is adsorbed on the surface to obtain a linear preform;

S4. Heat-treat the pre-finished product obtained in S3 for 2 minutes at a temperature of 130°C and a pressure of 3 MPa. After setting the thickness, cooling, and winding, obtain a thermoplastic plant fiber prepreg with a mass fraction of plant fibers of 60%. material.

The thermoplastic plant fiber prepreg obtained in this example is linear, with a density of 1.27g/cm ³ , a tensile strength of 55MPa, a tensile modulus of 5000Mpa, an elongation at break of 2.25%, a flexural strength of 65MPa, and a flexural modulus of It is 6000MPa, and the notched impact strength is 70J/m. The preparation method of this example is simple, has low requirements on the shape of the fiber material, and is suitable for mass production. The prepared prepreg can not only exert its light weight and high strength, but also has high bonding strength, is not easy to separate, has good tensile properties, and has good toughness. advantages, and has the characteristics of recyclable, reusable and easy to degrade.

Example 9

The preparation method of the thermoplastic plant fiber prepreg of the present embodiment, the method is:

S1, the preparation of fiber material, described fiber material is plant fiber material:

The specific preparation process of the plant fiber material: after the main trunk of the plant is soaked in water for 20 hours, mechanically rolled, fiber opened and dried, the plant fiber is obtained, and the plant fiber is lengthened, braided and twisted to obtain the plant fiber fiber material;

S2, preparation of thermoplastic polymer matrix:

After blending and modifying the polyamide thermoplastic matrix with a particle size of 198 μm to 350 μm with additives, a powdery thermoplastic polymer matrix is obtained; the additives are compatibilizer maleic anhydride grafted polypropylene, compatibilizer poly A mixture of vinyl alcohol, functional agent antioxidant KY-7910, functional agent UV absorber UVP-327 and functional agent light stabilizer GW-540;

S3, the preparation of pre-finished products:

Screen the thermoplastic polymer matrix with a particle size of 198 μm to 350 μm obtained in S2 into the powder tank, move the plant fiber material obtained in S1 forward at a speed of 3 m/min, pass through the powder tank, and the surface of the plant fiber material is adsorbed thermoplastic polymer matrix, resulting in linear preforms;

S4. Heat-treat the pre-finished product obtained in S3 for 2 minutes at a temperature of 350° C. and a pressure of 0.2 MPa. After setting the thickness, cooling, and winding, a thermoplastic plant fiber preform with a mass fraction of plant fibers of 70% is obtained. Dipping material.

The thermoplastic plant fiber prepreg obtained in this example is linear, with a density of 1.48g/cm ³ , a tensile strength of 150MPa, a tensile modulus of 8600Mpa, an elongation at break of 2.25%, a flexural strength of 200MPa, and a flexural modulus of It is 9000MPa, and the notched impact strength is 200J/m. The preparation method of this example is simple, has low requirements on the shape of the fiber material, and is suitable for mass production. The prepared prepreg can not only exert its light weight and high strength, but also has high bonding strength, is not easy to separate, has good tensile properties, and has good toughness. advantages, and has the characteristics of recyclable, reusable and easy to degrade.

Example 10

The preparation method of the thermoplastic plant fiber prepreg of the present embodiment, the method is:

S1, the preparation of fiber material, described fiber material is plant fiber material:

The specific preparation process of the plant fiber material: the leaves of the plant are soaked in water for 20 hours, mechanically rolled, fiber opened and dried to obtain plant fibers, and the plant fibers are lengthened, braided and twisted to obtain plant fibers. fiber material;

S2, preparation of thermoplastic polymer matrix:

After blending and modifying the polyamide thermoplastic matrix with a particle size of 198 μm to 350 μm with additives, a powdery thermoplastic polymer matrix is obtained; the additives are modifier silane coupling agent and functional agent UV absorber UV- 531 mixture;

S3, the preparation of pre-finished products:

The thermoplastic polymer matrix obtained in screening S2 with a particle size of 198 μm to 350 μm is put into a powder tank, and the plant fiber material obtained in S1 is moved forward at a speed of 0.3 m/min, passing through the powder tank, and the surface of the plant fiber material is Adsorption of thermoplastic polymer matrix to obtain linear preforms;

S4. Heat-treat the pre-finished product obtained in S3 for 3 minutes at a temperature of 200° C. and a pressure of 2.5 MPa. After setting the thickness, cooling, and winding, a thermoplastic plant fiber preform with a mass fraction of plant fibers of 65% is obtained. Dipping material.

The thermoplastic plant fiber prepreg obtained in this example is linear, with a density of 1.48g/cm ³ , a tensile strength of 155MPa, a tensile modulus of 8800Mpa, an elongation at break of 2.15%, a flexural strength of 205MPa, and a flexural modulus of It is 9100MPa, and the notched impact strength is 220J/m. The preparation method of this example is simple, has low requirements on the shape of the fiber material, and is suitable for mass production. The prepared prepreg can not only exert its light weight and high strength, but also has high bonding strength, is not easy to separate, has good tensile properties, and has good toughness. advantages, and has the characteristics of recyclable, reusable and easy to degrade.

The above descriptions are only preferred embodiments of the present invention, and do not limit the present invention in any way. All simple modifications, changes and equivalent changes made to the above embodiments according to the technical essence of the invention still belong to the protection scope of the technical solution of the invention.

Claims (2)

1. a preparation method of thermoplastic plant fiber prepreg, is characterized in that, the method is: S1. Preparation of fiber material, the water content of the fiber material is ≤12%, and the fiber material includes plant fiber material and bamboo strips: The specific preparation process of the plant fiber material: after soaking the bast part, stem part or leaves or seeds of the plant in water for 0h to 48h, mechanical rolling, fiber opening and drying, the plant fiber is obtained, and the plant fiber is Splicing, braiding and twisting to obtain plant fiber materials; The specific preparation process of bamboo strips is as follows: sawing off the bamboo, flattening the bamboo joints, opening the bamboo joints from the inside of the bamboo, splitting them into bamboo strips, removing the inner and outer joints, cutting and drying to obtain bamboo strips; S2, preparation of thermoplastic polymer matrix: When the thermoplastic matrix is a thermoplastic matrix sheet or thermoplastic matrix strip, the thermoplastic matrix is modified by adding additives and blended, and then hot-pressed at a temperature of 120°C to 350°C and a pressure of 0.1MPa to 0.5MPa to obtain Thermoplastic polymer matrix; When the thermoplastic matrix is a powder material, the thermoplastic polymer matrix is obtained by adding additives, blending and modifying the thermoplastic matrix; The thermoplastic matrix is one or both of polyethylene thermoplastic matrix, polypropylene thermoplastic matrix or polyamide thermoplastic matrix; S3, the preparation of pre-finished products: The plant fiber material obtained in S1 is used to pave at least one layer of fiber layer on the thermoplastic polymer matrix obtained in S2, and then the thermoplastic polymer matrix is arranged on the fiber layer to form a pre-product of the board structure; the fiber layer When the number of paving layers is multi-layer, 0°～90° paving is used between each layer; the thermoplastic polymer matrix is a thermoplastic polymer sheet; Or mix the bamboo strips obtained in S1 with the thermoplastic polymer matrix obtained in S2 to obtain a planar preform; the thermoplastic polymer matrix is a thermoplastic polymer tape; Or adsorb the thermoplastic polymer matrix obtained in S2 to the surface of the plant fiber material obtained in S1 to obtain a linear preform; the thermoplastic polymer matrix is a powder material with a particle size of 198 μm to 350 μm; S4. Heat-treat the pre-finished product obtained in S3 at a temperature of 120°C to 350°C and a pressure of 0.1MPa to 9MPa for 0.5min to 3min, and after thickness setting, cooling and winding, a thermoplastic plant fiber prepreg is obtained material; When the thermoplastic matrix in the preform is polyethylene, the heat treatment temperature is 120°C to 180°C; When the thermoplastic matrix in the preform is polypropylene, the heat treatment temperature is 150°C to 180°C; When the thermoplastic matrix in the pre-finished product is polyamide, the heat treatment temperature is 170°C to 350°C; The mass fraction of the plant fibers in the thermoplastic plant fiber prepreg is 5% to 70%, and the plant fibers in the thermoplastic plant fiber prepreg are plant fiber materials and bamboo strips. 2. the preparation method of a kind of thermoplastic plant fiber prepreg according to claim 1 is characterized in that, the auxiliary agent described in S2 is more than one in modifying agent, compatibilizer or functional agent; The modifying agent is more than one of thermoplastic acrylic resin and silane coupling agent; the compatibilizer is more than one of maleic anhydride grafted polypropylene and polyvinyl alcohol; the functional agent is antioxidant, ultraviolet ray More than one of absorber, light stabilizer, environment-friendly flame retardant and cooling masterbatch; the ultraviolet absorber is ultraviolet absorber UVP-327, and the light stabilizer is light stabilizer GW-540.