CN103802411B - A kind of Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material and preparation method thereof, orientations aramid fiber 1313 nanofiber is prepared specifically by method of electrostatic spinning, then with spinning nanofiber for reinforcement through dipping, hot pressing Static Spinning aramid fiber 1313 nanofiber strengthens lactic acid composite material, optimize preparation technology present system, define the preparation method that Static Spinning aramid fiber 1313 nanofiber strengthens lactic acid composite material, by the orientation of the aramid fiber 1313 layers of nanofibers controlling height-oriented arrangement regulate composite by different directions External Force Acting time bearing capacity, obtain and there is the same sex in length and breadth strengthen lactic acid composite material with the aramid fiber 1313 nanofiber of different in nature tensile mechanical properties in length and breadth, this product obtained is expected to be applied to lightweight member field.

Description

A kind of electrospun aramid fiber 1313 nanofiber/polylactic acid composite material and preparation method thereof

technical field

The invention belongs to the technical field of composite materials, and in particular relates to an electrospun aramid fiber 1313 nanometer fiber/polylactic acid composite material and a preparation method thereof.

Background technique

Electrospinning is a new spinning technology for preparing nanometer fibers. Under the action of high-voltage electrostatic field, polymer solution (or melt) can be spun into fibers with diameters ranging from tens of nanometers to hundreds of nanometers. Since the method has the advantages of simple equipment and low cost, researchers have been conducting research in this area since Formhals in the United States invented electrospinning technology in 1934; after the 1990s, with the development of nanotechnology, electrospinning The preparation and application of nanofibers has become one of the research hotspots in the field of nanomaterials. Currently, hundreds of natural materials and polymers have been successfully spun into electrospun nanofibers. The prepared product has also been developed from an initial fiber mat in which the fibers are randomly arranged to a fiber mat in which the fibers are oriented in a controlled manner.

Aramid 1313 is a new type of fiber material spun from polyphenylene isophthalamide (PMIA). The heat resistance of the fiber is particularly outstanding. After continuous use at 260°C for 1000 hours, it can still maintain 65% of the original strength, and at 300°C for one week, it can maintain 50% of the original strength. In addition, it has excellent flame retardancy, Electrical insulation, chemical stability, radiation resistance and mechanical properties, so it is widely used in special protective clothing, high temperature filter materials, electrical insulation materials, reinforcement materials and honeycomb structure wall materials, etc. The current research on aramid 1313 fiber mainly focuses on the development and performance research of its composite material, but there is very little research on electrospun aramid 1313 nanofiber.

Chinese invention patent application CN101838888A discloses a preparation method of electrospun meta-aramid nanofibers; Chinese invention patent application CN102704028A discloses a preparation method of meta-aramid nano spider web fiber film. The form of the product obtained by the above method is a fiber mat with randomly arranged fibers. This mat material has defects such as disordered and difficult-to-control fiber aggregate structure, limited secondary processing of the product, and can only be used in a single form.

In addition, polylactic acid (PLA) is a biodegradable plastic made from lactic acid obtained by fermentation of renewable substances and then synthesized. Polylactic acid is a thermoplastic material with stable performance at room temperature, with a glass transition temperature of about 60°C and a melting point of about 175°C. Polylactic acid is non-toxic, has good biocompatibility and good plasticity, and is suitable for various processing methods such as blow molding, extrusion, and injection molding. Another feature of polylactic acid is biodegradability. It can be completely degraded by natural microorganisms under certain conditions, and finally generate carbon dioxide and water without causing any pollution to the environment. However, polylactic acid is hard, brittle, easy to crack, small elongation at break, and poor impact resistance. It can usually be used as a matrix to prepare polymer/fiber composites to obtain better mechanical properties and expand its application fields.

At present, there is no report on the use of electrospun aramid 1313 nanofibers to reinforce polylactic acid polymers and prepare composite materials.

Contents of the invention

The purpose of the present invention is to provide an electrospun aramid fiber 1313 nanofiber/polylactic acid composite material and a preparation method thereof.

In order to achieve the above-mentioned purpose of the invention, the technical scheme adopted in the present invention is:

A preparation method of electrospinning aramid fiber 1313 nanofiber/polylactic acid composite material, comprising the following steps:

(1) Add anhydrous lithium chloride to the polar solvent to form a dissolution system containing lithium chloride, add aramid fiber 1313 fiber to the dissolution system, and dissolve it to obtain a spinning solution containing aramid fiber 1313; in the spinning solution , by mass, the content of aramid fiber 1313 is 8-16%, and the content of lithium chloride is 5-8%;

(2) Using electrospinning method to obtain aramid 1313 nanofiber mat with directional fibers;

(3) Dissolving polylactic acid in dichloromethane to obtain a polylactic acid solution with a mass concentration of 2-6%;

(4) Lay up two pieces of aramid 1313 nanofiber mats obtained in step (2), and then dip them into the polylactic acid solution obtained in step (3), and the solvent in the impregnated aramid 1313 nanofiber mats will naturally volatilize Then obtain aramid fiber 1313 nanofiber felt/polylactic acid prepreg sheet;

(5) The electrospun aramid 1313 nanofiber mat/polylactic acid composite material is obtained by thermoforming the aramid 1313 nanofiber mat/polylactic acid prepreg sheet; the pressure during the thermoforming is 600-3000MPa , the temperature is 170-190° C., and the time is 20-35 minutes.

In a preferred technical solution, in the step (1), the anhydrous lithium chloride is first vacuum-dried at 100-120° C. for 2-5 hours, and then added to a polar solvent to form a lithium chloride-containing dissolution system.

In the above technical solution, in the step (1), the polar solvent is dimethylacetamide.

In the above technical solution, in the step (1), the temperature for dissolving the aramid 1313 fiber is 80-130°C.

In the above technical solution, in the step (2), the electrospinning conditions are: the spinning voltage is 20-30KV, the inner diameter of the spinneret is 0.35-0.85mm, the flow rate of the spinning solution is 0.1-0.6ml/h, and the speed of the collecting roller is 4-9m/min, the lateral movement speed of the spinneret is 10-26cm/min, and the spinning distance is 8-15cm.

In the above-mentioned technical scheme, in the step (4), the superimposition mode of the two sheets of aramid 1313 nanofiber mats is any of the following: the fibers in the two fiber mats are arranged in a single direction, the fibers in the two fiber mats It is staggered at 45°, and the fibers in the two fiber mats are staggered at 90°.

In the above technical solution, in the step (5), after the prepreg is formed by hot pressing, the pressure is kept constant, and after cooling at room temperature, the electrospun aramid 1313 nanofiber mat/polylactic acid composite is obtained through trimming. Material.

The invention also discloses the electrospun aramid fiber 1313 nanofiber mat/polylactic acid composite material prepared according to the above method.

Due to the application of the above-mentioned technical solution, the present invention has the following advantages compared with the prior art:

1. The present invention combines electrospun aramid 1313 nanofibers with polylactic acid for the first time, and prepares a fiber-reinforced polymer composite material with light weight and excellent mechanical properties through hot pressing;

2. The present invention adopts an optimized process to prepare highly oriented aramid 1313 nanofiber mats, which overcomes the defect of random arrangement of fibers in the prior art; Electrospun aramid 1313 nanofiber-reinforced polylactic acid composite material with mechanical properties can be used to adjust the load-bearing capacity of the composite material when it is subjected to external forces in different directions;

3. In the preparation method disclosed by the invention, the raw materials are easy to obtain, the reaction conditions are mild, the reaction time is short, the equipment requirements are low, the production cost is low, and it is suitable for industrial production.

Description of drawings

Figure 1 is a schematic diagram of the stacking method of two aramid 1313 nanofiber mats in the embodiment, wherein A is that the fibers in the two fiber mats are staggered at 90°, and B is that the fibers in the two fiber mats are staggered at 45° , C is that the fibers in the two fiber mats are arranged in a single direction;

Fig. 2 is the scanning electron micrograph of electrospun aramid fiber 1313 nanofiber mat in embodiment two;

Fig. 3 is a photo of the electrospun aramid 1313 nanofiber mat reinforced polylactic acid composite material in Example 2.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

Embodiment one

Weigh a certain amount of anhydrous LiCl, dry it in vacuum at 120°C for 2 hours, then add it to DMAc to form a LiCl/DMAc solution system, weigh a certain amount of aramid 1313 fiber, add it to the LiCl/DMAc solution system, and heat it at 120°C Dissolve into a transparent solution under stirring, wherein the mass fraction of aramid fiber 1313 is 11%, and the mass fraction of LiCl is 7%;

At the spinning voltage of 26kv, the inner diameter of the spinneret is 0.85mm, the flow rate of the spinning solution is 0.45ml/h, the speed of the collecting roller is 9m/min, the lateral movement speed of the spinneret is 16cm/min, the spinning distance is 15cm, and the spinning time is 18h Spinning is carried out under the condition of , and the aramid fiber 1313 nanometer fiber felt of fiber alignment is prepared;

Referring to accompanying drawing 1A, the fiber in the above-mentioned two pieces of orientation alignment aramid 1313 nanofiber membranes of above-mentioned spinning is arranged in a staggered manner at 90°, then immersed in the methylene chloride solution of PLA, the PLA mass fraction in the solution is 7%, and then The solvent is completely evaporated at room temperature to obtain a prepreg;

Place the prepreg between two flat glass plates, apply a pressure of 2200MPa, heat-treat it in an oven at 190°C for 30 minutes, then keep the pressure constant, cool it at room temperature, and then trim it to obtain electrospun aramid fiber 1313 nanofiber/polylactic acid composite.

Embodiment two

Weigh a certain amount of anhydrous LiCl, dry it in vacuum at 120°C for 3 hours, then add it to DMAc to form a LiCl/DMAc solution system, weigh a certain amount of aramid fiber 1313, add it to the LiCl/DMAc solution system, and heat it at 100°C Dissolve into a transparent solution under stirring, wherein the mass fraction of aramid 1313 is 14%, and the mass fraction of LiCl is 5%;

At a spinning voltage of 24kv, the inner diameter of the spinneret is 0.85mm, the flow rate of the spinning solution is 0.3ml/h, the speed of the collecting roll is 8m/min, the lateral movement speed of the spinneret is 20cm/min, the spinning distance is 13cm, and the spinning time is 14h Spinning is carried out under the condition of , and the aramid fiber 1313 nanometer fiber felt of fiber alignment is prepared;

Referring to accompanying drawing 1B, the fiber in the above-mentioned two pieces of orientation alignment aramid 1313 nanofiber membranes of above-mentioned spinning is arranged in a staggered manner at 45°, then immersed in the methylene chloride solution of PLA, the PLA mass fraction in the solution is 3%, and then The solvent is completely evaporated at room temperature to obtain a prepreg;

Place the prepreg between two flat glass plates, apply a pressure of 1400MPa, heat-treat it in an oven at 180°C for 20 minutes, then keep the pressure constant, cool it at room temperature, and trim it to obtain electrospun aramid 1313 nanofiber/polylactic acid composite.

Accompanying drawing 2 is the scanning electron micrograph of the aramid 1313 nanofiber mat prepared above, it can be seen that the nanofibers are uniform in shape and have a good degree of orientation arrangement, which is very beneficial as a directional reinforcing fiber material.

Accompanying drawing 3 is the photo of the electrospun aramid fiber 1313 nanofiber/polylactic acid composite material prepared above, it can be seen that the composite material is well formed, the surface is relatively smooth, there is no obvious crack, and the adhesion between the fiber and the matrix is good.

Embodiment three

Weigh a certain amount of anhydrous LiCl, dry it in vacuum at 110°C for 4 hours, then add it to DMAc to form a LiCl/DMAc solution system, weigh a certain amount of aramid 1313 fiber, add it to the LiCl/DMAc solution system, and heat it at 110°C Dissolve into a transparent solution under stirring, wherein the mass fraction of aramid fiber 1313 is 10%, and the mass fraction of LiCl is 7%;

At the spinning voltage of 25kv, the inner diameter of the spinneret is 0.85mm, the flow rate of the spinning solution is 0.35ml/h, the speed of the collecting roller is 7m/min, the lateral movement speed of the spinneret is 18cm/min, the spinning distance is 13cm, and the spinning time is 16h Spinning is carried out under the condition of , and the aramid fiber 1313 nanometer fiber felt of fiber alignment is prepared;

Referring to accompanying drawing 1B, the fiber in the above-mentioned two pieces of orientation alignment aramid 1313 nanofiber membranes of above-mentioned spinning is arranged in a staggered manner at 45°, then immersed in the methylene chloride solution of PLA, the PLA mass fraction in the solution is 5%, and then The solvent is completely evaporated at room temperature to obtain a prepreg;

Place the prepreg between two flat glass plates, apply a pressure of 1800MPa, heat-treat it in an oven at 185°C for 25 minutes, then keep the pressure constant, cool it at room temperature, and then trim it to obtain electrospun aramid fiber 1313 nanofiber/polylactic acid composite.

Embodiment four

Weigh a certain amount of anhydrous LiCl, dry it in vacuum at 100°C for 2 hours, then add it to DMAc to form a LiCl/DMAc solution system, weigh a certain amount of aramid 1313 fiber, add it to the LiCl/DMAc solution system, and heat it at 100°C Dissolve into a transparent solution under stirring, wherein the mass fraction of aramid fiber 1313 is 12%, and the mass fraction of LiCl is 6%;

At the spinning voltage of 23kv, the inner diameter of the spinneret is 0.85mm, the flow rate of the spinning solution is 0.26ml/h, the speed of the collecting roller is 6m/min, the lateral movement speed of the spinneret is 14cm/min, the spinning distance is 11cm, and the spinning time is 12h Spinning is carried out under the condition of , and the aramid fiber 1313 nanometer fiber felt of fiber alignment is prepared;

Referring to accompanying drawing 1C, arrange the fibers in the above-mentioned two sheets of orientation alignment aramid 1313 nanofiber membranes in a single direction, then dip in the methylene chloride solution of PLA, the PLA mass fraction in the solution is 3%, and then in The solvent is completely evaporated at room temperature to obtain a prepreg;

Place the prepreg between two flat glass plates, apply a pressure of 1000MPa, heat-treat it in an oven at 185°C for 30 minutes, then keep the pressure constant, cool it at room temperature, and then trim it to obtain electrospun aramid 1313 nanofiber/polylactic acid composite.

Performance Testing

Prepare dumbbell-shaped splines along the longitudinal and transverse directions of the fibers in the electrospun aramid 1313 nanofiber/polylactic acid composite material prepared above, and stretch them on an Instron5967 electronic strength meter after equilibrating for 24 hours under standard atmospheric pressure conditions Mechanical property test. The specific data of the obtained tensile properties are shown in Table 1.

Table 1 Characterization of mechanical properties of composite materials

Fiber mass fraction/% Longitudinal tensile breaking strength/MPa Transverse tensile breaking strength/MPa Embodiment one 18.96 9.72 9.45 Embodiment two 45.63 10.62 6.87 Embodiment three 27.17 12.33 7.26 Embodiment four 39.61 18.65 6.51

From the measured experimental data, it can be found that the arrangement of fibers between laminated fiber mats is different, and the loads that can be borne in the longitudinal and transverse stretching directions are different. The electrospun aramid 1313 nanofiber/polylactic acid composite material (Example 1) in which the reinforcing fiber layer is staggered at 90°, the maximum load that can be borne when stretched longitudinally is similar to that when stretched transversely, and has the characteristics of vertical and horizontal isotropy; The electrospun aramid 1313 nanofiber/polylactic acid composite material (Examples 2 and 3) in which the reinforcement fiber layer is staggered at 45°, when stretched longitudinally, the maximum load that the composite material can bear is also greater than that stretched transversely, and also has vertical and horizontal Anisotropic characteristics, but the difference between the two is less than when the reinforcing fibers are arranged in a single direction; the electrospun aramid 1313 nanofiber/polylactic acid composite material (Example 4) in which the reinforcing fibers are arranged in a single direction, the longitudinal stretch can The maximum load it bears is much greater than that of the transverse stretch, the former is more than twice that of the latter, that is, it has significant aspect characteristics. It can be seen that, by adopting the method of the present invention, according to the stress characteristics during the use of the composite material, the bearing capacity of the composite material when subjected to external forces in different directions can be adjusted by controlling the arrangement direction of the highly oriented and arranged aramid fiber 1313 nanofiber layer ability.

Claims (8)

1. a preparation method for Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material, is characterized in that, comprises the following steps:

(1) in polar solvent, add anhydrous Lithium chloride, form the dissolution system of chloride containing lithium, aramid fiber 1313 is joined in dissolution system, dissolve the spinning solution obtained containing aramid fiber 1313; In spinning solution, in mass, the content of aramid fiber 1313 is 8 ~ 16%, and the content of lithium chloride is 5 ~ 8%;

(2) adopt electrospinning process, obtain fiber in the aramid fiber 1313 nanofiber mats aligned;

(3) PLA is dissolved in carrene, obtains the PLA solution that mass concentration is 2 ~ 6%;

(4) aramid fiber 1313 nanofiber mats two panels step (2) obtained is superimposed, then impregnated in the PLA solution that step (3) obtains, after the solvent in the aramid fiber 1313 nanofiber mats after to be impregnated volatilizees naturally, namely obtain aramid fiber 1313 nanofiber mats/PLA prepreg;

(5) aramid fiber 1313 nanofiber mats/PLA prepreg is obtained described Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material through hot-forming; Described hot-forming time pressure be 600 ~ 3000MPa, temperature is 170 ~ 190 DEG C, and the time is 20 ~ 35 minutes.

2. the preparation method of Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material according to claim 1, it is characterized in that: in step (1), anhydrous Lithium chloride is vacuum drying 2 ~ 5h under 100 ~ 120 DEG C of conditions first, then joins in polar solvent, forms the dissolution system of chloride containing lithium.

3. the preparation method of Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material according to claim 1, it is characterized in that: in step (1), polar solvent is dimethylacetylamide.

4. the preparation method of Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material according to claim 1, is characterized in that: in step (1), and temperature when dissolving aramid fiber 1313 is 80 ~ 130 DEG C.

5. the preparation method of Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material according to claim 1, it is characterized in that: in step (2), electrospinning conditions is, spinning voltage 20 ~ 30kV, spinning head is internal diameter 0.35 ~ 0.85mm, spinning solution flow 0.1 ~ 0.6mL/h, collecting drum rotating speed 4 ~ 9m/min, spinning head transverse shifting speed 10 ~ 26cm/min, spinning distance 8 ~ 15cm.

6. the preparation method of Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material according to claim 1, it is characterized in that: in step (4), the congruent manner of two panels aramid fiber 1313 nanofiber mats be following any one: to be fiber in single direction arrangement, two panels fibrofelt be the fiber in two panels fibrofelt that 45 ° are staggered, fiber in two panels fibrofelt is 90 ° and is staggered.

7. the preparation method of Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material according to claim 1, it is characterized in that: in step (5), prepreg is after hot-forming, keep pressure constant, under room temperature after cooling, obtain described Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material through finishing.

8. according to the Static Spinning aramid fiber 1313 nanometer fiber/polylactic acid composite material that any one method in claim 1 ~ 7 prepares.