Method for improving performance of jute epoxy resin composite material by modifying through alkali-ultrasonic sol-gel method

文档序号：845462 发布日期：2021-03-16 浏览：8次中文

阅读说明：本技术 一种采用碱--超声溶胶凝胶法改性提高黄麻环氧树脂复合材料性能的方法 (Method for improving performance of jute epoxy resin composite material by modifying through alkali-ultrasonic sol-gel method ) 是由张星张鹏张得昆于 2020-06-16 设计创作，主要内容包括：本发明提供了一种采用碱-超声溶胶凝胶法改性提高黄麻/环氧树脂复合材料性能的方法。通过将黄麻纤维制成具有三维网状结构的非织造布,然后对其进行碱-超声溶胶凝胶法改性处理,使黄麻纤维孔隙率增加,比表面积增大,形成的纳米粒子填充在黄麻纤维的孔隙与沟槽中,降低吸水率,提高黄麻纤维表面粗糙度,从而增加了黄麻纤维与树脂基体的界面结合强度。然后将经过改性处理后的黄麻纤维非织造布作为增强体,以环氧树脂为基体,采用RTM工艺制备出力学性能显著提升的黄麻/环氧树脂复合材料。(The invention provides a method for improving the performance of a jute/epoxy resin composite material by modifying by an alkali-ultrasonic sol-gel method. The jute fiber is made into the non-woven fabric with the three-dimensional net structure, and then the non-woven fabric is subjected to alkali-ultrasonic sol-gel method modification treatment, so that the porosity and the specific surface area of the jute fiber are increased, the formed nano particles are filled in the pores and the grooves of the jute fiber, the water absorption is reduced, the surface roughness of the jute fiber is improved, and the interface bonding strength of the jute fiber and a resin matrix is increased. Then, the modified jute fiber non-woven fabric is used as a reinforcement, epoxy resin is used as a matrix, and the RTM process is adopted to prepare the jute/epoxy resin composite material with remarkably improved mechanical property.)

1. A method for improving the performance of a jute/epoxy resin composite material by modifying by an alkali-ultrasonic sol-gel method is characterized by sequentially comprising the following steps of:

step 1, preparing jute fiber non-woven fabric, which comprises the following process flows: fiber raw material → mixed opening → carded web → lapping → needle punching reinforcement → jute fiber non-woven fabric;

step 2, cleaning and pretreating the jute fiber non-woven fabric: soaking jute fiber non-woven fabric in distilled water at 50 ℃ for 20-30 min to remove dust and impurities on the surface of the non-woven fabric, taking out the jute fiber non-woven fabric, placing the jute fiber non-woven fabric in an oven at 80 ℃, drying for 6 hours, and taking out the jute fiber non-woven fabric for later use;

step 3, alkali modification treatment of the jute fiber non-woven fabric obtained in the step 2: preparing a sodium hydroxide solution with the concentration of 3-7%, cutting the jute fiber non-woven fabric obtained in the step 2, weighing, wherein the mass ratio of the jute fiber non-woven fabric to the sodium hydroxide solution is 1:40, respectively soaking the jute fiber non-woven fabric obtained in the step 2 in the sodium hydroxide solution for 1-3 h, then taking out, washing with distilled water and glacial acetic acid until the washing liquid is neutral, placing the washed liquid in an oven with the temperature of 90 ℃ for drying for 6h, and then taking out to obtain alkali-treated jute fiber non-woven fabric;

step 4, performing ultrasonic sol-gel modification treatment on the jute fiber non-woven fabric obtained in the step 3: adding 0.5-2.5% ammonia water into 400ml of absolute ethyl alcohol, ultrasonically stirring for 10min, marking as a solution I, adding 20ml of TEOS reagent into 100ml of absolute ethyl alcohol, adding a certain amount of distilled water (TEOS: 1), ultrasonically stirring for 10min, marking as a solution II, dropping the solution II into the solution I, sealing a beaker with a polyethylene film, ultrasonically stirring for 1h, then marking as a solution III, soaking the jute fiber non-woven fabric sample treated in the step 3 into the solution III, placing the jute fiber non-woven fabric sample into a water bath kettle at 40-80 ℃ for reacting for 6h, taking out the treated jute non-woven fabric, ageing for 24h at room temperature, respectively cleaning for 3 times and 1 time by using distilled water and ethanol, and then placing the jute fiber non-woven fabric in an oven at 90 ℃ for 5h, and obtaining alkali-ultrasonic sol-gel treated jute fiber non-woven fabric;

step 5, preparing the jute/epoxy resin composite material: and (3) taking the alkali-ultrasonic sol-gel treated jute fiber non-woven fabric obtained in the step (4) as a reinforcement, taking epoxy resin as a matrix, and preparing the jute/epoxy resin composite material by adopting an RTM (resin transfer molding) process, wherein the epoxy resin and a curing agent are mixed according to the ratio of 100: 85, injecting the mixture into a mold paved with the reinforcement from a reaction kettle, setting the injection temperature to be 55 ℃, setting the first-stage curing temperature to be 90 ℃ and the time to be 2 hours, and setting the second-stage curing temperature to be 110 ℃ and the time to be 1 hour; and the third stage curing temperature is 135 ℃, the curing time is 6 hours, and the jute/epoxy resin composite material is prepared by cooling to room temperature and then demoulding.

2. The method for improving the performance of the jute/epoxy resin composite material by modifying through an alkali-ultrasonic sol-gel method according to claim 1, wherein the jute fiber content in the process flow for preparing the jute fiber non-woven fabric in the step 1 is not less than 85 percent, the sum of the total content of the polypropylene fibers is 100 percent, and the needling density in the reinforcing process is 150 to 300 spines/cm²And the needling depth is 5-11 mm.

Technical Field

The invention belongs to the technical field of fiber reinforced composite material processing, and relates to a method for improving the performance of a jute/epoxy resin composite material by modifying through an alkali-ultrasonic sol-gel method

Background

With the deep thought of the concept of 'green and environment protection', the composite material will develop towards the directions of environmental friendliness, sustainability and the like. The jute fiber has the excellent properties and characteristics of high specific modulus and specific strength, wide and cheap sources, reproducibility, degradability and recyclability, can produce composite materials with high strength and light weight, and has attracted much attention and research in the field of composite materials in recent years. The jute fiber composite material has wide application and can be applied to the fields of automobile interiors, automobile outer plates, sound absorption and heat insulation, building materials and the like. However, in the preparation of jute composite materials, if jute fibers are directly used as reinforcement to prepare composite materials, cellulose, hemicellulose and the like in the jute fibers contain a large amount of hydrophilic hydroxyl groups, and strong hydrogen bonding action among cellulose macromolecular chains causes the jute fibers to show stronger polarity and hydrophilicity, so that the problem of poor interface compatibility between the jute fibers and a hydrophobic resin matrix is caused. Thereby causing a reduction in the properties of the composite material produced. Therefore, if the problem is solved well, the comprehensive performance of the final composite material can be effectively improved.

A nonwoven fabric is a fabric formed without the need to spin a woven fabric, which is a sheet or web of oriented or randomly arranged fibers made by rubbing, entangling, or bonding. The jute fiber of the dry-method needle-punched non-woven fabric prepared by the invention is in a three-dimensional structure in the net, and the jute fiber is used as a reinforcement of a composite material, so that the problem of low interlayer strength is solved, and the dry-method needle-punched non-woven fabric has the advantages of short production flow and low cost. Therefore, the jute fiber is made into non-woven fabric, and is modified by adopting an alkali-ultrasonic sol-gel treatment mode to be used as a reinforcement, so that the mechanical property of the finally prepared composite material can be effectively improved.

Disclosure of Invention

The invention aims to provide a method for improving the performance of a jute/epoxy resin composite material by modification of an alkali-ultrasonic sol-gel method, which utilizes the unique surface effect of micro-nano particles to fill in pores and grooves of jute fibers, reduces the capillary effect of the jute fibers, reduces the water absorption and improves the interface combination of the jute fibers and a resin matrix on the one hand; on the other hand, the micro-nano particles are attached to the surface of the jute fiber, so that the surface roughness of the jute fiber is improved, and a mechanical locking effect is generated between the surface of the jute fiber and a resin matrix, so that the interface bonding strength of the jute fiber and the resin matrix is improved, and the mechanical property of the jute/epoxy resin composite material is finally improved.

The technical scheme provided by the invention is as follows:

a method for improving the performance of a jute/epoxy resin composite material by modifying by an alkali-ultrasonic sol-gel method sequentially comprises the following steps:

step 5, preparing the jute/epoxy resin composite material: and (3) taking the alkali-ultrasonic sol-gel treated jute fiber non-woven fabric obtained in the step (4) as a reinforcement, taking epoxy resin as a matrix, and preparing the jute/epoxy resin composite material by adopting an RTM (resin transfer molding) process, wherein the epoxy resin and a curing agent are mixed according to the ratio of 100: 85, and injecting the mixture into a mold with a spread reinforcement from a reaction kettle, wherein the injection temperature is set to be 55 ℃. The curing temperature of the first stage is 90 ℃ for 2 hours, and the curing temperature of the second stage is 110 ℃ for 1 hour; and the third stage curing temperature is 135 ℃, the curing time is 6 hours, and the jute/epoxy resin composite material is prepared by cooling to room temperature and then demoulding.

Further, in the process flow for preparing the jute fiber non-woven fabric in the step 1, the content of jute fibers is not less than 85 percent, the sum of the total content of the polypropylene fibers is 100 percent, the needling density in the reinforcing process is 150-300 needling/cm 2, and the needling depth is 5-11 mm.

Compared with the prior art, the invention has the following beneficial effects: according to the invention, the jute fiber is modified by adopting an alkali-ultrasonic sol-gel treatment mode, and the compatibility between the jute fiber and a resin matrix is improved, so that the interface bonding strength of the jute fiber and the resin matrix is improved, and the mechanical property of the jute/epoxy resin composite material can be effectively improved; the method has the advantages of safe raw materials, low cost, simple process, remarkable effect and the like. The invention provides the following technical scheme:

drawings

FIG. 1 is an electron micrograph of a modified jute fiber nonwoven fabric in example 1.

FIG. 2 is a graph showing tensile properties before and after modification of the jute/epoxy resin composite prepared in example 2.

FIG. 3 is a graph showing the bending properties of the jute/epoxy resin composite material prepared in example 3 before and after modification.

FIG. 4 is a graph showing compression properties before and after modification of the jute/epoxy resin composite prepared in example 4.

Detailed Description

The technical solution of the present invention is clearly and completely described below with reference to specific embodiments. It is obvious that the described embodiments are only some of the embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention is further described with reference to the following figures and detailed description.

Example 1

Step 1, preparing jute fiber non-woven fabric, which comprises the following process flows: fiber raw material → mixed opening → carded web → lapping → needle punching reinforcement → jute fiber non-woven fabric; wherein the jute fiber content is 90%, the polypropylene fiber content is 10%, and the needling density is 150 needles/cm²And the needling depth is 11 mm.

Step 2, cleaning and pretreating the jute fiber non-woven fabric: soaking jute fiber non-woven fabric in distilled water of 50 deg.C for 30min to remove dust and impurities on the surface of the non-woven fabric, taking out, placing in an oven of 80 deg.C, drying for 6 hr, and taking out for use.

Step 3, alkali modification treatment of the jute fiber non-woven fabric obtained in the step 2: preparing a sodium hydroxide solution with the concentration of 3%, cutting the jute fiber non-woven fabric obtained in the step 2, weighing, wherein the mass ratio of the jute fiber non-woven fabric to the sodium hydroxide solution is 1:40, respectively soaking the jute fiber non-woven fabric obtained in the step 2 in the sodium hydroxide solution for 1h, then taking out, washing with distilled water and glacial acetic acid until the washing liquid is neutral, placing the jute fiber non-woven fabric in an oven at the temperature of 90 ℃, drying for 6h, and then taking out to obtain the alkali-treated jute fiber non-woven fabric.

Step 4, performing ultrasonic sol-gel modification treatment on the jute fiber non-woven fabric obtained in the step 3: adding 0.5% ammonia water into 400ml of absolute ethyl alcohol, ultrasonically stirring for 10min, marking as a solution I, adding 20ml of TEOS reagent into 100ml of absolute ethyl alcohol, adding a certain amount of distilled water (TEOS: distilled water is 1:1), ultrasonically stirring for 10min, marking as a solution II, dropping the solution into the solution I, sealing the opening of a beaker by using a polyethylene film, ultrasonically stirring for 1h, marking as a solution III, soaking the jute fiber non-woven fabric sample treated in the step 3 into the solution III, placing the jute fiber non-woven fabric sample in a water bath kettle at 40 ℃ for reacting for 6h, taking out the treated jute non-woven fabric, ageing for 24h at room temperature, respectively cleaning for 3 times and 1 time by using distilled water and ethanol, and then placing the jute fiber non-woven fabric in an oven at 90 ℃ for 5h, thus obtaining the alkali-ultrasonic gel treated jute fiber non-woven fabric.

Step 5, preparing the jute/epoxy resin composite material: and (3) taking the alkali-ultrasonic sol-gel treated jute fiber non-woven fabric obtained in the step (4) as a reinforcement, taking epoxy resin as a matrix, and preparing the jute/epoxy resin composite material by adopting an RTM (resin transfer molding) process, wherein the epoxy resin and a curing agent are mixed according to the ratio of 100: 85, and injecting the mixture into a mold with a spread reinforcement from a reaction kettle, wherein the injection temperature is set to be 55 ℃. The curing temperature of the first stage is 90 ℃ for 2 hours, and the curing temperature of the second stage is 110 ℃ for 1 hour; and the third stage curing temperature is 135 ℃, the curing time is 6 hours, and the jute/epoxy resin composite material is prepared by cooling to room temperature and then demoulding.

Example 2

Step 2 is the same as step 2 in example 1.

Step 3, alkali modification treatment of the jute fiber non-woven fabric obtained in the step 2: preparing a sodium hydroxide solution with the concentration of 3%, cutting the jute fiber non-woven fabric obtained in the step 2, weighing, wherein the mass ratio of the jute fiber non-woven fabric to the sodium hydroxide solution is 1:40, respectively soaking the jute fiber non-woven fabric obtained in the step 2 in the sodium hydroxide solution for 3 hours, then taking out, washing with distilled water and glacial acetic acid until the washing liquid is neutral, placing the jute fiber non-woven fabric in an oven at the temperature of 90 ℃, drying for 6 hours, and then taking out to obtain the alkali-treated jute fiber non-woven fabric.

Step 4, performing ultrasonic sol-gel modification treatment on the jute fiber non-woven fabric obtained in the step 3: adding 2.5% ammonia water into 400ml of absolute ethyl alcohol, ultrasonically stirring for 10min, marking as a solution I, adding 20ml of TEOS reagent into 100ml of absolute ethyl alcohol, adding a certain amount of distilled water (TEOS: distilled water is 1:1), ultrasonically stirring for 10min, marking as a solution II, dropping the solution into the solution I, sealing the opening of a beaker by using a polyethylene film, ultrasonically stirring for 1h, marking as a solution III, soaking the jute fiber non-woven fabric sample treated in the step 3 into the solution III, placing the jute fiber non-woven fabric sample in a water bath kettle at 80 ℃ for reacting for 6h, taking out the treated jute non-woven fabric, ageing for 24h at room temperature, respectively cleaning for 3 times and 1 time by using distilled water and ethanol, and then placing the jute fiber non-woven fabric in an oven at 90 ℃ for 5h, thus obtaining the alkali-ultrasonic gel treated jute fiber non-woven fabric.

Step 5 is the same as step 5 in example 1.

Example 3

Step 1 preparation of Jute nonwoven FabricThe process flow is as follows: fiber raw material → mixed opening → carded web → lapping → needle punching reinforcement → jute fiber non-woven fabric; wherein the jute fiber content is 85%, the polypropylene fiber content is 15%, and the needling density is 200 needles/cm²And the needling depth is 9 mm.

Step 2, cleaning and pretreating the jute fiber non-woven fabric: soaking jute fiber non-woven fabric in distilled water of 50 deg.C for 20min to remove dust and impurities on the surface of the non-woven fabric, taking out, placing in an oven of 80 deg.C, drying for 6 hr, and taking out for use.

Step 3, alkali modification treatment of the jute fiber non-woven fabric obtained in the step 2: preparing a 7% sodium hydroxide solution, cutting the jute fiber non-woven fabric obtained in the step 2, weighing, wherein the mass ratio of the jute fiber non-woven fabric to the sodium hydroxide solution is 1:40, respectively soaking the jute fiber non-woven fabric obtained in the step 2 in the sodium hydroxide solution for 1h, then taking out, washing with distilled water and glacial acetic acid until the washing liquid is neutral, placing the jute fiber non-woven fabric in an oven at 90 ℃ for drying for 6h, and then taking out to obtain the alkali-treated jute fiber non-woven fabric.

Step 4, performing ultrasonic sol-gel modification treatment on the jute fiber non-woven fabric obtained in the step 3: adding 2.5% ammonia water into 400ml of absolute ethyl alcohol, ultrasonically stirring for 10min, marking as a solution I, adding 20ml of TEOS reagent into 100ml of absolute ethyl alcohol, adding a certain amount of distilled water (TEOS: distilled water is 1:1), ultrasonically stirring for 10min, marking as a solution II, dropping the solution into the solution I, sealing the opening of a beaker by using a polyethylene film, ultrasonically stirring for 1h, marking as a solution III, soaking the jute fiber non-woven fabric sample treated in the step 3 into the solution III, placing the jute fiber non-woven fabric sample in a water bath kettle at 60 ℃ for reacting for 6h, taking out the treated jute non-woven fabric, ageing for 24h at room temperature, respectively cleaning for 3 times and 1 time by using distilled water and ethanol, and then placing the jute fiber non-woven fabric in an oven at 90 ℃ for 5h, thus obtaining the alkali-ultrasonic gel treated jute fiber non-woven fabric.

Step 5 is the same as step 5 in example 1.

Example 4

Step 1 preparation of jute fiberThe process flow of the vitamin non-woven fabric is as follows: fiber raw material → mixed opening → carded web → lapping → needle punching reinforcement → jute fiber non-woven fabric; wherein the jute fiber content is 85 percent, the polypropylene fiber content is 15 percent, and the needling density is 300 spines/cm²And the needling depth is 7 mm.

Step 2 is the same as step 2 in example 3.

Step 3, alkali modification treatment of the jute fiber non-woven fabric obtained in the step 2: preparing a sodium hydroxide solution with the concentration of 5%, cutting the jute fiber non-woven fabric obtained in the step 2, weighing, wherein the mass ratio of the jute fiber non-woven fabric to the sodium hydroxide solution is 1:40, respectively soaking the jute fiber non-woven fabric obtained in the step 2 in the sodium hydroxide solution for 2 hours, then taking out, washing with distilled water and glacial acetic acid until the washing liquid is neutral, placing the jute fiber non-woven fabric in an oven with the temperature of 90 ℃ for drying for 6 hours, and then taking out to obtain the alkali-treated jute fiber non-woven fabric.

Step 4, performing ultrasonic sol-gel modification treatment on the jute fiber non-woven fabric obtained in the step 3: adding ammonia water with the concentration of 1.5% into 400ml of absolute ethyl alcohol, ultrasonically stirring for 10min, marking as a solution I, adding 20ml of TEOS reagent into 100ml of absolute ethyl alcohol, adding a certain amount of distilled water (TEOS: distilled water is 1:1), ultrasonically stirring for 10min, marking as a solution II, dropping the solution into the solution I, sealing the opening of a beaker by using a polyethylene film, ultrasonically stirring for 1h, marking as a solution III, soaking the jute fiber non-woven fabric sample treated in the step 3 into the solution III, placing the jute fiber non-woven fabric sample in a water bath kettle at the temperature of 60 ℃ for reacting for 6h, taking out the treated jute non-woven fabric, ageing for 24h at room temperature, respectively cleaning for 3 times and 1 time by using distilled water and ethanol, and then placing the jute fiber non-woven fabric in an oven at the temperature of 90 ℃ for 5h, thus obtaining the alkali-ultrasonic gel treated jute fiber non-woven fabric.

Step 5 is the same as step 5 in example 1.

From the electron microscope photograph (fig. 1) of the modified jute fiber non-woven fabric in example 1, it can be seen that the modified jute fiber has grooves on the surface thereof, and a large number of micro-nano particles are deposited in the grooves on the surface of the fiber. From the graph of the tensile properties before and after modification of the jute/epoxy resin composite material prepared in example 2 (fig. 2), the graph of the bending properties before and after modification of the jute/epoxy resin composite material prepared in example 3 (fig. 3) and the graph of the compression properties before and after modification of the jute/epoxy resin composite material prepared in example 4 (fig. 4), it can be seen that the mechanical properties of the modified composite material are remarkably improved.

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