CN107541016B - A kind of preparation method of biomass modified epoxy resin - Google Patents

Abstract

The invention provides a preparation method of biomass modified epoxy resin. The biomass raw material is dried, pulverized, sieved, and further ground into powder; the biomass powder is mixed with epoxy resin, stirred at 60°C for 20min, then heated to 80°C, and reacted for 1h to obtain biomass-modified epoxy resin Resin prepolymer; adding a curing agent into the modified epoxy resin prepolymer and curing to obtain a modified epoxy resin material. The method of the invention has the advantages of wide source of raw materials, low price, simple preparation process, easy operation and the like. The modified epoxy resin obtained by the preparation method of the present invention has good stability, and the tensile strength and bending strength of the material can be increased by 46.3% and 36.1% respectively at the highest; the impact resistance can be improved by up to 94.2%. The obtained modified epoxy resin can be directly used as a resin material for electrical and electronic materials, aerospace materials and engineering plastics, and can also be used as a matrix resin for composite materials.

Description

A kind of preparation method of biomass modified epoxy resin

technical field

The invention relates to a method for modifying a thermosetting resin, in particular to a method for preparing a natural biomass modified epoxy resin.

Background technique

As a kind of thermosetting resin material, epoxy resin has excellent performance, has good bonding strength on metal and non-metal surfaces, is stable to alkali and most solvents, and has excellent dielectric properties, good heat and humidity resistance , high insulation performance, good dimensional stability and processing performance, it can be widely used in various fields such as civil and national defense as adhesives, laminating materials, coatings and casting materials.

Epoxy resin is the most widely used matrix in the field of polymer-based composite materials. It is suitable for a variety of molding processes. It has a long storage time, does not release small molecular organic matter during curing, and has low curing shrinkage. The cured product has excellent properties. Dimensional stability. Epoxy resin composite materials are widely used in the aerospace field, such as aircraft radomes, helicopter rotors, solid rocket motor shells, system components, etc.; in the civilian field, the main applications include FRP pressure vessels and pipes, anti-corrosion products Wait.

Contents of the invention

The object of the present invention is to provide a kind of preparation method of the biomass modified epoxy resin that can improve the stability, tensile strength, bending strength, impact strength of product, raw material is cheap and easy to obtain, process is simple, easy to operate.

The purpose of the present invention is achieved like this:

(1) The biomass raw material is dried, pulverized, sieved, and further ground into powder;

(2) Mix biomass powder with epoxy resin, stir at 60°C for 20 minutes, then raise the temperature to 80°C, and react for 1 hour to obtain a biomass-modified epoxy resin prepolymer;

(3) adding a curing agent into the modified epoxy resin prepolymer and curing to obtain a modified epoxy resin material.

The present invention may also include:

1. The biomass is catechin, pomegranate peel or walnut peel.

2. The drying of biomass raw materials is to dry the biomass at 60°C for 8 hours under vacuum, and the average particle size of the biomass powder is 0.1-20 μm. Preferably it is 0.5 to 2 μm.

3. The mass ratio of biomass powder to epoxy resin is 0.5/100-10/100. Preferably it is 1/100 to 2/100.

4. The epoxy resin includes bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, o-cresol novolac epoxy resin One or a mixture of several.

5. The curing agent includes one or a mixture of 4,4-diaminodiphenylmethane, m-phenylenediamine, alicyclic polyamine, aromatic polyamine, tertiary amine and imidazole curing agent .

6. The curing is medium temperature curing, and the specific conditions are: pre-curing for 1-3 hours at 80-110°C and post-curing for 2-6 hours at 120-180°C.

In order to improve the mechanical properties of epoxy resin and expand its application range, the present invention adopts biomass with wide sources and low price (such as catechu, pomegranate peel, walnut peel, etc.) to modify epoxy resin, effectively improving the environmental protection effect. Tensile strength, flexural strength and impact resistance of epoxy resin. The method has the advantages of simple preparation process and easy operation, and the obtained modified epoxy resin has good stability and wide application prospects, and can be directly used as a resin material for electronic and electrical materials, aerospace materials and engineering plastics, It can also be used as a matrix resin for composite materials.

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

(1) The preparation method of biomass-modified epoxy resin provided by the present invention, the natural biomass (such as catechu, pomegranate peel, walnut peel, etc.) adopted has the advantages of wide source of raw materials, low price, renewable, green and environmental protection , and can effectively improve the tensile strength, flexural strength and impact strength of epoxy resin after adding a small amount.

(2) The preparation method of the biomass-modified epoxy resin provided by the present invention has the advantages of mild conditions, simple process, easy operation, small equipment investment, and easy large-scale production.

(3) The biomass-modified epoxy resin obtained by the preparation method of the present invention has excellent mechanical properties, and can be directly used as a resin material in the fields of electronic appliances, aerospace and engineering plastics; and due to the introduction of biomass, it can Effectively improve the compatibility of epoxy resin with organic and inorganic reinforcing fillers and reinforcing fibers, so using it as the matrix resin of composite materials can effectively improve the performance of composite materials.

Detailed ways

The present invention is further described with examples below. The scope of the present invention is not limited by these examples.

Comparative example 1:

(1) Add 25 parts by mass of curing agent 4,4-diaminodiphenylmethane (DDM) to epoxy resin with 100 parts by mass, heat and stir at 80°C to completely dissolve the curing agent in epoxy resin;

(2) The mixture of the above-mentioned epoxy resin and curing agent is placed in a vacuum oven for 15 minutes to remove air bubbles;

(3) Pour the defoamed mixture into the prepared mold, place it in a blast drying oven, and cure it at 80°C for 2 hours and at 135°C for 4 hours. Mechanical property test.

The test results show that the tensile strength and bending strength of the epoxy resin are 67.6MPa and 108.4MPa respectively, the elongation at break is 6.3%, and the impact strength is 11.05kJ/m ² (see Table 1).

Example 1:

(1) Place the biomass catechu in a vacuum oven at 60°C for 8 hours, crush it into small particles, remove impurities with a 50-mesh sieve, and grind the obtained powder into a fine powder with a ball mill;

(2) Mix the catechin powder with a mass fraction of 1 and the epoxy resin with a mass fraction of 100, stir at 60°C for 20 minutes to mix the catechin particles and the epoxy resin liquid evenly, then heat up to 80°C, and react 1h, obtain catechin modified epoxy resin prepolymer;

(3) Add the curing agent DDM with 25 parts by mass into the above-mentioned catechin modified epoxy resin prepolymer, keep the temperature at 80° C., and stir to completely dissolve the curing agent;

(4) The above mixture is placed in a vacuum oven for 15 minutes to remove air bubbles;

(5) Pour the defoamed mixture into the prepared mold, place it in a blast drying oven, and cure it at 80°C for 2 hours, and at 135°C for 4 hours. Mechanical property test.

The test results showed that the tensile strength and flexural strength of the modified epoxy resin were 91.8MPa and 147.4MPa respectively, the elongation at break was 6.6%, and the impact strength was 21.5kJ/m ² (see Table 1).

Example 2:

Except that the mass fraction of catechin powder was 1.5, other conditions were all the same as in Example 1. The mechanical performance test results of the obtained modified epoxy resin show that its tensile strength and bending strength are respectively 98.9MPa and 145.3MPa, the elongation at break is 6.4%, and the impact strength is 19.3kJ/m ² (see Table 1) .

Example 3:

Except that the biomass adopted is pomegranate peel, other conditions are all identical with embodiment 1. The mechanical performance test results of the obtained modified epoxy resin show that its tensile strength and bending strength are respectively 95.4MPa and 120.1MPa, the elongation at break is 6.8%, and the impact strength is 18.3kJ/m ² (see Table 1) .

Comparative example 2:

(1) Add the curing agent m-phenylenediamine (PDA) with 13 parts by mass to the epoxy resin with 100 parts by mass, heat and stir at 80° C., so that the curing agent is completely dissolved in the epoxy resin;

(2) The mixture of the above-mentioned epoxy resin and curing agent is placed in a vacuum oven for 15 minutes to remove air bubbles;

(3) Pour the defoamed mixture into the prepared mold, place it in a blast drying oven, and cure it at 80°C for 1 hour, 105°C for 1 hour, and 150°C for 2 hours. After 24 hours at room temperature, the mechanical property test was carried out.

The test results showed that the tensile strength and bending strength of the epoxy resin were 63.9MPa and 105.8MPa respectively, and the elongation at break was 3.6% (see Table 1).

Example 4:

(1) Place the biomass catechu in a vacuum oven at 60°C for 8 hours, crush it into small particles, remove impurities with a 50-mesh sieve, and grind the obtained powder into a fine powder with a ball mill;

(2) Mix the catechin powder with a mass fraction of 1 and the epoxy resin with a mass fraction of 100, stir at 60°C for 20 minutes to mix the catechin particles and the epoxy resin liquid evenly, then heat up to 80°C, and react 1h, obtain catechin modified epoxy resin prepolymer;

(3) adding the curing agent PDA with 13 parts by mass into the above-mentioned catechin modified epoxy resin prepolymer, keeping the temperature at 80° C., and stirring to completely dissolve the curing agent;

(4) The above mixture is placed in a vacuum oven for 15 minutes to remove air bubbles;

(5) Pour the defoamed mixture into the prepared mold, place it in a blast drying oven, and cure it at 80°C for 1 hour, 105°C for 1 hour, and 150°C for 2 hours. After 24 hours at room temperature, the mechanical property test was carried out.

The test results showed that the tensile strength and bending strength of the modified epoxy resin were 77.6MPa and 159.3MPa respectively, and the elongation at break was 5.2% (see Table 1).

Example 5:

Except that the biomass adopted is pomegranate peel, other conditions are all identical with embodiment 4. The mechanical performance test results of the obtained modified epoxy resin showed that its tensile strength and bending strength were 73.7MPa and 136.4MPa respectively, and the elongation at break was 6.0% (see Table 1).

Table 1 Mechanical properties of epoxy resin and biomass modified epoxy resin

Claims (7)

1. a kind of preparation method of biomass modified epoxy resin, it is characterized in that:

(1) biomass material dries pulverizing, sieving, and be further ground to powdered；

(2) powdered biomass is mixed with epoxy resin, stirs 20min at 60 DEG C, then heat to 80 DEG C, reacted 1h, obtain To biomass modified epoxy resin prepolymer, the mass ratio of powdered biomass and epoxy resin is 1/100~2/100；

(3) curing agent is added in modified epoxy performed polymer, solidifies, obtains modified epoxy material.

2. the preparation method of biomass modified epoxy resin according to claim 1, it is characterized in that: the biomass is youngster Tea, granatum or Cortex walnut.

3. the preparation method of biomass modified epoxy resin according to claim 1, it is characterized in that: the baking of biomass material Dry is by biomass in 60 DEG C of vacuum drying 8h, and the average grain diameter of powdered biomass is 0.1~20 μm.

4. the preparation method of biomass modified epoxy resin according to claim 3, it is characterized in that: powdered biomass is flat Equal partial size is 0.5~2 μm.

5. the preparation method of biomass modified epoxy resin according to claim 1, it is characterized in that: the epoxy resin Including bisphenol A type epoxy resin, bisphenol-A epoxy resin, bisphenol f type epoxy resin, bisphenol-s epoxy resin, adjacent first The mixture of one or more of novolac epoxy resin.

6. the preparation method of biomass modified epoxy resin according to claim 1, it is characterized in that: the curing agent packet Include one in 4,4- diaminodiphenylmethane, m-phenylene diamine (MPD), alicyclic polyamine, aromatic polyamine, tertiary amine and imidazole curing agent Kind or several mixtures.

7. the preparation method of biomass modified epoxy resin according to claim 1, it is characterized in that: described be cured as medium temperature Solidification, actual conditions are as follows: under the conditions of 80~110 DEG C under the conditions of the precuring of 1~3h and 120~180 DEG C 2~6h rear solidification.