CN104371275B - Epoxy resin composite material of nano-cellulose thermoplastic resin modified synergic and preparation method thereof - Google Patents

Abstract

The invention discloses a nano-cellulose-thermoplastic resin synergistically modified epoxy resin composite material and a preparation method thereof. It is made by blending epoxy resin, curing agent, thermoplastic resin and nanocellulose in a weight ratio of 100:27～33:7～33.3:0.1～0.3; adding nanocellulose to distilled water and ultrasonically dispersing to form a suspension; Add anhydrous ethanol for centrifugal replacement to remove water; add epoxy resin, magnetically stir and disperse, heat treatment to remove ethanol by volatilization; add thermoplastic resin oil bath and mechanically stir, cool down and add curing agent, continue to stir to obtain a blend; vacuum oven Remove the air bubbles in the medium, pour into the mold, and then heat and solidify to prepare the epoxy resin composite material synergistically modified by nanocellulose and thermoplastic resin. The invention selects environment-friendly and green nano-cellulose and thermoplastic resin to jointly modify the epoxy resin, improves the interface bonding force, and realizes synergistic strengthening and toughening of the epoxy resin.

Description

Nanocellulose-thermoplastic resin synergistically modified epoxy resin composites and their Preparation

technical field

The invention belongs to the technical field of resin-based composite materials, and relates to a composite material and a preparation method thereof, in particular to a nanocellulose-thermoplastic resin synergistically modified epoxy resin composite material and a preparation method thereof.

Background technique

Due to the advantages of low curing shrinkage, strong adhesion, high mechanical properties of cured products, good chemical resistance, and good electrical insulation properties, epoxy resin has an irreplaceable position in fiber-reinforced resin-based composite materials. Used in aerospace, aviation, automobile, construction and other fields. However, due to the highly cross-linked epoxy resin during the curing process, the cured product has defects such as brittleness and poor impact resistance, which limits its application in engineering. This requires that the epoxy resin must be modified.

By introducing the second phase material into the epoxy resin, forming a certain microstructure and increasing energy dissipation is an important toughening method. Among them, the modification of epoxy resin by thermoplastic resin (such as polysulfone, polyethersulfone, polyimide, etc.) has attracted much attention. However, the modified system prepared by this method often shows a relatively clear phase structure interface after curing reaction, indicating that the interphase bonding force is not strong, so the toughening effect must be affected to a certain extent. With the development of nanotechnology, it has been found that using two modifiers to modify epoxy resin is an effective way to further improve the comprehensive performance of epoxy resin. Introduce different forms of nano fillers (such as carbon nanotubes, titanium dioxide, etc.) into the thermoplastic resin modified epoxy resin system to achieve the effect of synergistic reinforcement and toughening.

In recent years, due to the advantages of high strength, high modulus, high specific surface area, biodegradability and rich preparation raw materials, nanocellulose has attracted more and more attention from researchers, and has been widely used in reinforced composite materials and biomedical materials. and other fields. The use of nanocellulose instead of carbon nanotubes to strengthen epoxy resins meets the requirements of environmental protection to a certain extent and reduces environmental pollution. At the same time, it also avoids the safety and health problems that may be induced by the application of inorganic nanofillers. At present, although the research on the modification of pure epoxy resin system by nanocellulose has been carried out, it is still in its infancy, and there are problems that nanocellulose is difficult to disperse and the modification effect is not obvious. However, the research on the co-modification of epoxy resin with nanocellulose and thermoplastic resin has not been reported.

Contents of the invention

In order to solve the problems existing in the background technology, the present invention provides a nanocellulose-thermoplastic resin synergistically modified epoxy resin composite material and its preparation method. Thermoplastic resins synergistically reinforce and toughen epoxy resins.

The technical scheme adopted in the present invention is:

One, a kind of nano-cellulose-thermoplastic resin synergistically modified epoxy resin composite material:

It is composed of epoxy resin, curing agent, thermoplastic resin and nano-cellulose blended, and the weight ratio of epoxy resin, curing agent, thermoplastic resin and nano-cellulose is 100:27-33:7-33.3:0.1-0.3.

Two, a kind of nanocellulose-thermoplastic resin synergistically modified epoxy resin composite material preparation method, comprises the following steps:

1) Preparation of nanocellulose/epoxy resin system:

1.1) adding 0.1 to 0.3 parts by weight of nanocellulose to 100 to 300 parts by weight of distilled water, and ultrasonically oscillating until the nanocellulose is uniformly dispersed to form a stable suspension;

1.2) To the nanocellulose aqueous solution prepared in step 1.1), add absolute ethanol having the same weight portion as the distilled water in step 1.1) for centrifugal replacement, remove the water therein through replacement, and obtain the ethanol solution of nanocellulose; perform ultrasonication again Shake for 20 minutes until the nanocellulose is evenly dispersed in ethanol;

1.3) Add 100 parts by weight of epoxy resin to the solution prepared in step 1.2), carry out magnetic stirring and dispersion for 6 hours, then adjust the temperature to 80° C. for heat treatment for 4 hours, and remove ethanol by volatilization;

2) Preparation of nanocellulose/thermoplastic resin/epoxy resin composite system:

2.1) Add 7 to 33.3 parts by weight of thermoplastic resin in the epoxy resin obtained in step 1.3) to uniformly disperse the nanocellulose in an oil bath at 120 to 150° C., perform mechanical stirring for 2 to 4 hours, and then cool down to 60 to 60° C. Add 27-33 parts by weight of curing agent while stirring at 110°C, and continue stirring for 10-30 minutes to obtain a blend of nanocellulose, thermoplastic resin and epoxy resin;

2.2) The blend obtained in step 2.1) is evacuated in a vacuum oven for 20 to 40 minutes to remove air bubbles, and then poured into a polytetrafluoroethylene mold, and heated and solidified at normal pressure and at a temperature of 60 to 200°C. An epoxy resin composite material synergistically modified with nanocellulose and thermoplastic resin was prepared.

In step 1.3) after heat treatment for 4 hours, place in a vacuum oven at 80° C. for 4 hours of vacuum treatment to completely remove ethanol.

The epoxy resin is liquid bisphenol A epoxy resin E51, and the epoxy equivalent is 185-200g/eq.

The curing agent is an amine curing agent, specifically 4,4'-diaminodiphenylsulfone (DDS), 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylmethane (DDM ) or polyetheramine (D230), preferably 4,4'-diaminodiphenylsulfone (DDS).

The thermoplastic resin is polyimide (PI), polyetherimide (PEI), polysulfone (PSF) or polycaprolactone (PCL), preferably polysulfone.

The nanocellulose adopts cellulose nanofibers with high aspect ratio that are easy to penetrate and entangle, the average fiber length is 300-600um, and the average diameter is 50-100nm.

The invention aims to improve the interfacial cohesive force by controlling the interpenetration of nanocellulose between different phase regions and the interentanglement with thermoplastic resin during the phase separation process, thereby improving the effect of material reinforcement and toughening.

The present invention selects high-aspect-ratio nanocellulose with excellent mechanical properties, environmental protection, and rich sources, and uniformly disperses it in the epoxy resin matrix through a method of combining solvent exchange and melt blending. During the phase separation process, the high-aspect-ratio nanocellulose , Thermoplastic resin polymer chains are prone to entanglement. Through the penetration of nanocellulose between different phase regions and the entanglement with thermoplastic resin polymer chains, the interfacial adhesion is improved. At the same time, nanocellulose can regulate the size of the phase domain. The improvement of the bonding force of the phase interface and the regulation of the size of the phase domain are beneficial to the improvement of the mechanical properties of the material.

The mechanical properties of the synergistically modified epoxy resin composite material obtained in the present invention are improved compared with pure epoxy resin systems, pure nano-cellulose or thermoplastic resin modified epoxy resin composite systems.

The present invention has following beneficial effects:

1. The present invention uses nanocellulose instead of carbon nanotubes to strengthen epoxy resin, conforms to environmental protection requirements, reduces environmental pollution, and at the same time avoids safety and health problems that may be induced by the application of inorganic nanofillers.

2. The nanocellulose has not undergone any chemical modification, thereby preventing the reduction of the mechanical properties of the nanocellulose.

3. The content of nanocellulose is controlled in a relatively low range, and the method of solvent exchange is used to make it dispersed as uniformly as possible, so as to avoid the reduction of mechanical properties of the composite material caused by agglomeration due to high content of nanocellulose.

4. The synergistic modification of nanocellulose fibers with high aspect ratio and thermoplastic resin is used to improve the interfacial bonding force and improve the material performance through the interpenetration of different phases of nanocellulose and the intertwining with thermoplastic resin polymer chains.

Description of drawings

FIG. 1 is a SEM image of a section of a composite material prepared in Example 1 of the present invention.

Fig. 2 is an SEM image of a cross-section of a polysulfone-modified epoxy resin composite material in the same proportion as in Example 1 of the present invention.

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Embodiments of the present invention are as follows:

The present inventor obtained the optimal process for preparing nanocellulose/thermoplastic resin/epoxy resin composite material through repeated research and verification of a large number of experiments. The implementation of the present invention will be specifically described below in conjunction with several representative embodiments, but the following embodiments do not constitute a limitation to the present invention.

Example 1

The raw materials and dosage are:

The above-mentioned high aspect ratio nanocellulose fibers have an average length of 300-600um and an average diameter of 50-100nm.

a) Add 0.1 g of nanocellulose fibers to a beaker with 100 ml of distilled water, and ultrasonically vibrate for 20 minutes until the nanocellulose fibers are evenly dispersed to form a stable suspension;

b) adding 100 g of absolute ethanol to the aqueous solution of nanocellulose fibers prepared in step a) for centrifugation and replacement, removing the water therein through 5 replacements to obtain an ethanol solution of nanocellulose fibers; performing ultrasonic oscillation treatment for 20 minutes again, Until the nanocellulose fibers are evenly dispersed in ethanol;

c) Add 100 g of liquid bisphenol A epoxy resin E51 to the solution prepared in step b), carry out magnetic stirring and disperse for 6 hours, then adjust the temperature to 80° C. for heat treatment for 4 hours, and remove ethanol by volatilization; Vacuumize for another 4 hours in a vacuum oven at 80°C to further remove ethanol;

d) Transfer the bisphenol A type epoxy resin E51 in which the nanocellulose fibers uniformly disperse in step c) to a flask, add 14.1 g of polysulfone and mechanically stir it in an oil bath at 140° C. for 3 hours, then cool down to 110° C. Add the DDS of 27g while stirring after ℃, continue to stir for 30 minutes, obtain nanocellulose fiber, polysulfone (PSF) and bisphenol A type epoxy resin E51 blend;

e) The blend obtained in step d) was evacuated in a vacuum oven for 30 minutes to remove air bubbles, then poured into a polytetrafluoroethylene mold, and then followed the first stage of the curing process at 160° C. for 6 hours under normal pressure, In the second stage at 180°C for 2h and in the third stage at 200°C for 2h, heat treatment was carried out, and after cooling to room temperature and demoulding, the mechanical test specimens were obtained.

The composite material prepared by the present embodiment has a tensile strength of 83MPa, a tensile modulus of elasticity of 2.8GPa, and an impact strength of 24KJ/m ² ; the tensile strength of the pure liquid bisphenol A type epoxy resin E51 matrix is 81MPa, The tensile elastic modulus is 2.6GPa, and the impact strength is 18KJ/m ² ; the tensile strength of the polysulfone modified epoxy resin composite material in the same proportion is 74MPa, the tensile elastic modulus is 2.7GPa, and the impact strength is 20KJ /m ² . It can be seen that the joint modification of epoxy resin with nanocellulose and thermoplastic resin polysulfone can achieve a synergistic effect of strengthening and toughening.

It can be seen from the comparison of the SEM images of Fig. 1 and Fig. 2 that the composite material prepared in the embodiment of the present invention and the polysulfone-modified epoxy resin system in the same proportion have formed a shape in which polysulfone particles are uniformly dispersed in the epoxy resin matrix. The nano-cellulose has no obvious agglomeration phenomenon, and the addition of nano-cellulose obviously improves the interfacial cohesion, so the mechanical properties of the prepared composite material are significantly improved, and have significant technical effects.

Example 2

The raw materials and dosage are:

The above-mentioned high aspect ratio nanocellulose fibers have an average length of 300-600um and an average diameter of 50-100nm.

a) Add 0.2 g of nanocellulose fibers into a beaker containing 200 ml of distilled water, and ultrasonically vibrate for 20 minutes until the nanocellulose fibers are evenly dispersed to form a stable suspension;

b) adding 200 g of absolute ethanol to the aqueous solution of nanocellulose fibers prepared in step a) for centrifugation and replacement, and removing the water therein through 5 replacements to obtain an ethanol solution of nanocellulose fibers; performing ultrasonic oscillation treatment for 20 minutes again, Until the nanocellulose fibers are evenly dispersed in ethanol;

c) Add 100 g of liquid bisphenol A epoxy resin E51 to the solution prepared in step b), carry out magnetic stirring and disperse for 6 hours, then adjust the temperature to 80° C. for heat treatment for 4 hours, and remove ethanol by volatilization; Vacuumize for another 4 hours in a vacuum oven at 80°C to further remove ethanol;

d) Transfer the bisphenol A type epoxy resin E51 in which the nanocellulose fibers uniformly disperse in step c) to a flask, add 14.1 g of polysulfone and mechanically stir it in an oil bath at 140° C. for 3 hours, then cool down to 110° C. Add the DDS of 27g while stirring after ℃, continue to stir for 30 minutes, obtain nanocellulose fiber, polysulfone (PSF) and bisphenol A type epoxy resin E51 blend;

e) The blend obtained in step d) was evacuated in a vacuum oven for 30 minutes to remove air bubbles, then poured into a polytetrafluoroethylene mold, and then followed the first stage of the curing process at 160° C. for 6 hours under normal pressure, In the second stage at 180°C for 2h and in the third stage at 200°C for 2h, heat treatment was carried out, and after cooling to room temperature and demolding, the mechanical test specimens were obtained.

The tensile strength of the composite material prepared in this example is 85MPa, the tensile modulus of elasticity is 2.8GPa, and the impact strength is 31KJ/m ² , indicating that the mechanical properties of the composite material continue to increase with the increase of the nanocellulose content. The co-modification of epoxy resin with nanocellulose and thermoplastic resin polysulfone can achieve a synergistic effect of strengthening and toughening.

Example 3

The raw materials and dosage are:

The above-mentioned high aspect ratio nanocellulose fibers have an average length of 300-600um and an average diameter of 50-100nm.

a) Add 0.3 g of nanocellulose fibers to a beaker containing 300 ml of distilled water, and ultrasonically vibrate for 20 minutes until the nanocellulose fibers are evenly dispersed to form a stable suspension;

b) adding 300 g of absolute ethanol to the aqueous solution of nanocellulose fibers prepared in step a) for centrifugation and replacement, removing the water therein through 5 replacements to obtain an ethanol solution of nanocellulose fibers; performing ultrasonic oscillation treatment for 20 minutes again, Until the nanocellulose fibers are evenly dispersed in ethanol;

c) Add 100 g of liquid bisphenol A epoxy resin E51 to the solution prepared in step b), carry out magnetic stirring and disperse for 6 hours, then adjust the temperature to 80° C. for heat treatment for 4 hours, and remove ethanol by volatilization; Vacuumize for another 4 hours in a vacuum oven at 80°C to further remove ethanol;

d) Transfer the bisphenol A type epoxy resin E51 in which the nanocellulose fibers uniformly disperse in step c) to a flask, add 14.1 g of polysulfone and mechanically stir it in an oil bath at 140° C. for 3 hours, then cool down to 110° C. Add the DDS of 27g while stirring after ℃, continue to stir for 30 minutes, obtain nanocellulose fiber, polysulfone (PSF) and bisphenol A type epoxy resin E51 blend;

e) The blend obtained in step d) was evacuated in a vacuum oven for 30 minutes to remove air bubbles, then poured into a polytetrafluoroethylene mold, and then followed the first stage of the curing process at 160° C. for 6 hours under normal pressure, In the second stage at 180°C for 2h and in the third stage at 200°C for 2h, heat treatment was carried out, and after cooling to room temperature and demolding, the mechanical test specimens were obtained.

The tensile strength of the composite material prepared in this example is 86MPa, the tensile modulus of elasticity is 2.8GPa, and the impact strength is 26KJ/m ² , indicating that the joint modification of epoxy resin with nanocellulose and thermoplastic resin polysulfone can play a synergistic role. Enhance toughening effect.

Example 4

The raw materials and dosage are:

The above-mentioned high aspect ratio nanocellulose fibers have an average length of 300-600um and an average diameter of 50-100nm.

a) Add 0.1 g of nanocellulose fibers to a beaker with 100 ml of distilled water, and ultrasonically vibrate for 20 minutes until the nanocellulose fibers are evenly dispersed to form a stable suspension;

b) adding 100 g of absolute ethanol to the aqueous solution of nanocellulose fibers prepared in step a) for centrifugation and replacement, removing the water therein through 5 replacements to obtain an ethanol solution of nanocellulose fibers; performing ultrasonic oscillation treatment for 20 minutes again, Until the nanocellulose fibers are evenly dispersed in ethanol;

c) Add 100 g of liquid bisphenol A epoxy resin E51 to the solution prepared in step b), carry out magnetic stirring and disperse for 6 hours, then adjust the temperature to 80° C. for heat treatment for 4 hours, and remove ethanol by volatilization; Vacuumize for another 4 hours in a vacuum oven at 80°C to further remove ethanol;

d) Transfer the bisphenol A type epoxy resin E51 in which the nanocellulose fibers uniformly disperse in step c) to a flask, add 17.3 g of polysulfone and mechanically stir it in an oil bath at 140° C. for 3 hours, then cool down to 110° C. Add the DDS of 27g while stirring after ℃, continue to stir for 30 minutes, obtain nanocellulose fiber, polysulfone (PSF) and bisphenol A type epoxy resin E51 blend;

e) The blend obtained in step d) was evacuated in a vacuum oven for 30 minutes to remove air bubbles, then poured into a polytetrafluoroethylene mold, and then followed the first stage of the curing process at 160° C. for 6 hours under normal pressure, In the second stage at 180°C for 2h and in the third stage at 200°C for 2h, heat treatment was carried out, and after cooling to room temperature and demolding, the mechanical test specimens were obtained.

The composite material prepared by the present embodiment has a tensile strength of 76MPa, a tensile modulus of elasticity of 2.8GPa, and an impact strength of 25KJ/ ^m2 ; the tensile strength of the epoxy resin composite material modified by polysulfone in the same proportion is 66MPa, and the The modulus of elasticity is 2.8GPa, and the impact strength is 17KJ/m2. It can be seen that the joint modification of epoxy resin with nanocellulose and thermoplastic resin polysulfone can achieve a synergistic effect of strengthening and toughening.

Example 5

The raw materials and dosage are:

The above-mentioned high aspect ratio nanocellulose fibers have an average length of 300-600um and an average diameter of 50-100nm.

a) Add 0.3 g of nanocellulose fibers to a beaker containing 300 ml of distilled water, and ultrasonically vibrate for 20 minutes until the nanocellulose fibers are evenly dispersed to form a stable suspension;

b) adding 300 g of absolute ethanol to the aqueous solution of nanocellulose fibers prepared in step a) for centrifugation and replacement, removing the water therein through 5 replacements to obtain an ethanol solution of nanocellulose fibers; performing ultrasonic oscillation treatment for 20 minutes again, Until the nanocellulose fibers are evenly dispersed in ethanol;

c) Add 100 g of liquid bisphenol A epoxy resin E51 to the solution prepared in step b), carry out magnetic stirring and disperse for 6 hours, then adjust the temperature to 80° C. for heat treatment for 4 hours, and remove ethanol by volatilization; Vacuumize for another 4 hours in a vacuum oven at 80°C to further remove ethanol;

d) The bisphenol A type epoxy resin E51 obtained in step c) where the nanocellulose fibers are uniformly dispersed is transferred to a flask, wherein 33.3 g of polycaprolactone is added and mechanically stirred in an oil bath at 120° C. for 2 hours, then cooled Add the DDS of 33g while stirring to 110 DEG C, continue to stir for 30 minutes, obtain nanocellulose fiber, polycaprolactone (PCL) and bisphenol A type epoxy resin E51 blend;

e) The blend obtained in step d) was evacuated in a vacuum oven for 40 minutes to remove air bubbles, then poured into a polytetrafluoroethylene mold, and then followed the first stage of the curing process at 160° C. for 6 hours under normal pressure, In the second stage, heat treatment was carried out at 180°C for 2 hours, and mechanical test specimens were obtained after cooling to room temperature and demoulding.

The composite material tensile strength prepared by the present embodiment is 34MPa, and tensile modulus of elasticity is 1.7GPa, and impact strength is 26KJ/m ² ; The epoxy resin composite material tensile strength of polycaprolactone modification in the same proportion is 33MPa , the tensile modulus of elasticity is 1.7GPa, and the impact strength is 14KJ/m2. It can be seen that the joint modification of epoxy resin with nanocellulose and thermoplastic resin polycaprolactone can achieve a synergistic toughening effect.

Example 6

The raw materials and dosage are:

The above-mentioned high aspect ratio nanocellulose fibers have an average length of 300-600um and an average diameter of 50-100nm.

a) Add 0.1 g of nanocellulose fibers to a beaker with 100 ml of distilled water, and ultrasonically vibrate for 20 minutes until the nanocellulose fibers are evenly dispersed to form a stable suspension;

b) adding 100 g of absolute ethanol to the aqueous solution of nanocellulose fibers prepared in step a) for centrifugation and replacement, removing the water therein through 5 replacements to obtain an ethanol solution of nanocellulose fibers; performing ultrasonic oscillation treatment for 20 minutes again, Until the nanocellulose fibers are evenly dispersed in ethanol;

c) Add 100 g of liquid bisphenol A epoxy resin E51 to the solution prepared in step b), carry out magnetic stirring and disperse for 6 hours, then adjust the temperature to 80° C. for heat treatment for 4 hours, and remove ethanol by volatilization; Vacuumize for another 4 hours in a vacuum oven at 80°C to further remove ethanol;

d) Transfer the bisphenol A type epoxy resin E51 in which the nanocellulose fibers uniformly disperse in step c) to a flask, add 14.1 g of polysulfone and mechanically stir it in an oil bath at 140° C. for 3 hours, then cool down to 80° C. Add the DDM of 27g while stirring after ℃, continue to stir for 10 minutes, obtain nanocellulose fiber, polysulfone (PSF) and bisphenol A type epoxy resin E51 blend;

e) The blend obtained in step d) was evacuated in a vacuum oven for 20 minutes to remove air bubbles, then poured into a polytetrafluoroethylene mold, and then followed the first stage of the curing process at 100°C for 2 hours under normal pressure, In the second stage, heat treatment was performed at 160°C for 6h and in the third stage at 180°C for 2h, and the mechanical test specimens were obtained after cooling to room temperature and demoulding.

Compared with the above-mentioned Example 1, this example has the same preparation method, but the difference lies in the type of curing agent. The composite material prepared by this embodiment can also achieve the purpose of synergistic modification.

Example 7

The raw materials and dosage are:

The above-mentioned high aspect ratio nanocellulose fibers have an average length of 300-600um and an average diameter of 50-100nm.

a) Add 0.1 g of nanocellulose fibers to a beaker with 100 ml of distilled water, and ultrasonically vibrate for 20 minutes until the nanocellulose fibers are evenly dispersed to form a stable suspension;

b) adding 100 g of absolute ethanol to the aqueous solution of nanocellulose fibers prepared in step a) for centrifugation and replacement, removing the water therein through 5 replacements to obtain an ethanol solution of nanocellulose fibers; performing ultrasonic oscillation treatment for 20 minutes again, Until the nanocellulose fibers are evenly dispersed in ethanol;

c) Add 100 g of liquid bisphenol A epoxy resin E51 to the solution prepared in step b), carry out magnetic stirring and disperse for 6 hours, then adjust the temperature to 80° C. for heat treatment for 4 hours, and remove ethanol by volatilization; Vacuumize for another 4 hours in a vacuum oven at 80°C to further remove ethanol;

d) The bisphenol A type epoxy resin E51 in which the nanocellulose fibers are uniformly dispersed obtained in step c) is transferred to a flask, wherein 7g of polyetherimide is added and mechanically stirred in an oil bath at 150° C. for 3 hours, then the temperature is lowered Add 31g of D230 while stirring to 60°C, and continue to stir for 20 minutes to obtain a blend of nanocellulose fibers, polyetherimide (PEI) and bisphenol A epoxy resin E51;

e) The blend obtained in step d) was evacuated in a vacuum oven for 20 minutes to remove air bubbles, then poured into a polytetrafluoroethylene mold, and then followed the first stage of the curing process at 80° C. for 2 hours under normal pressure, In the second stage at 120°C for 4h and in the third stage at 160°C for 2h, heat treatment was performed, and after cooling to room temperature and demolding, the mechanical test specimens were obtained.

In this example, polyetheramine is used as a curing agent, and polyetherimide is used as a thermoplastic resin to prepare a composite material. The preparation method is basically the same as that described in the previous examples. The composite material prepared by this embodiment can also achieve the purpose of synergistic modification.

Claims (5)

1. A nanocellulose-thermoplastic resin synergistically modified epoxy resin composite material is characterized in that: it is composed of epoxy resin, curing agent, thermoplastic resin and nanocellulose blending, epoxy resin, curing agent, thermoplastic The weight ratio of resin and nanocellulose is 100:27～33:7～33.3:0.1～0.3, the nanocellulose is unmodified nanocellulose fiber, and the thermoplastic resin is polyimide , polyetherimide, polysulfone or polycaprolactone; through the penetration of nanocellulose fibers between different phase regions and the entanglement with thermoplastic resin polymer chains, the interfacial adhesion is improved; The average fiber length of the nanocellulose is 300-600um, and the average diameter is 50-100nm. 2. a preparation method of a nanocellulose-thermoplastic resin synergistically modified epoxy resin composite material, characterized in that it may further comprise the steps: 1) Preparation of nanocellulose/epoxy resin system: 1.1) Add 0.1 to 0.3 parts by weight of nanocellulose to 100 to 300 parts by weight of distilled water, the nanocellulose is unmodified nanocellulose fiber, and the average length of the nanocellulose fiber is 300-600um, with an average diameter of 50-100nm, ultrasonically oscillate until the nanocellulose is uniformly dispersed to form a stable suspension; 1.2) Add the same weight of absolute ethanol as the distilled water in step 1.1) for centrifugal replacement, and remove the water after replacement to obtain the ethanol solution of nanocellulose; perform ultrasonic oscillation treatment for 20 minutes again until the nanocellulose is uniformly dispersed into ethanol; 1.3) Add 100 parts by weight of epoxy resin to the solution prepared in step 1.2), carry out magnetic stirring and dispersion for 6 hours, then adjust the temperature to 80°C for heat treatment for 4 hours, and volatilize and remove the ethanol; 2) Preparation of nanocellulose/thermoplastic resin/epoxy resin composite system: 2.1) Add 7 to 33.3 parts by weight of thermoplastic resin in an oil bath at 120 to 150°C to the epoxy resin in which nanocellulose is uniformly dispersed in step 1.3), the thermoplastic resin is polyimide, polyetheramide imine, polysulfone or polycaprolactone, mechanically stirred for 2-4 hours, cooled to 60-110°C, then added 27-33 parts by weight of curing agent while stirring, and continued stirring for 10-30 minutes to obtain nanocellulose , thermoplastic resin and epoxy resin blend; 2.2) The blend obtained in step 2.1) is evacuated in a vacuum oven for 20 to 40 minutes to remove air bubbles, and then poured into a polytetrafluoroethylene mold, and heated and cured at normal pressure at a temperature of 60 to 200°C. An epoxy resin composite material synergistically modified with nanocellulose and thermoplastic resin was obtained. 3. The preparation method of a nanocellulose-thermoplastic resin synergistically modified epoxy resin composite material according to claim 2, characterized in that: the step 1.3) is heated for 4 hours, and then placed in Vacuum treatment was carried out in a vacuum oven at 80° C. for 4 hours to completely remove ethanol. 4. A kind of nanocellulose-thermoplastic resin synergistically modified epoxy resin composite material according to claim 1 or a kind of nanocellulose-thermoplastic resin synergistically modified epoxy resin composite material according to claim 2 The preparation method is characterized in that: the epoxy resin is liquid bisphenol A type epoxy resin E51. 5. A kind of nanocellulose-thermoplastic resin synergistically modified epoxy resin composite material according to claim 1 or a kind of nanocellulose-thermoplastic resin synergistically modified epoxy resin composite material according to claim 2 The preparation method is characterized in that: the curing agent is an amine curing agent, specifically 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diamino diphenylmethane or polyetheramine.