CN109122600B - Nano tungsten trioxide feeding silkworm rearing method for preparing self-heating silk and product thereof - Google Patents

Abstract

The present invention provides a method for preparing self-producing hot silk by adding nano tungsten trioxide to feed silkworms and its products. 2. From the fourth instar, feed the compound feed with a mass fraction of 1%-1.5% nano-tungsten trioxide aqueous solution, the mass ratio of the aqueous solution to the feed is 1:(20-25), and the nano-tungsten trioxide is absorbed by the silkworm and enters Silk gland; Step 3, the compound feed is fed to the end of the fifth instar, and the nano-tungsten trioxide entering the silk gland is finally combined with the nano-tungsten trioxide into the silk during the spinning process, until the upper cocoon forms, that is, the self-producing hot silk is obtained. . It not only improves the toughness and strength of silk, but also makes it have excellent photothermal properties of tungsten trioxide. Improves the toughness of silk; destroys the silk structure and reduces the crystallinity.

Description

A kind of nanometer tungsten trioxide feeding silkworm breeding method for preparing self-producing hot silk and its products

technical field

The invention relates to the modification of silk fibers, in particular to a nano-tungsten trioxide feeding silkworm breeding method for preparing self-producing hot silk and its products.

Background technique

Silk is a continuous long fiber formed by the solidification of silk liquid secreted by mature silkworms when they form cocoons, also known as natural silk. As the lightest, thinnest, and softest natural fiber in nature, silk is not only widely used in textiles, clothing, medical care, cosmetics, etc., but also through various chemical and physical treatment methods to develop various new functional silks. Broaden new uses of silk.

Ordinary silk fabrics, such as silk quilts, thermal underwear, etc., have good bulkiness, warmth retention, air permeability, and smooth hand feel. However, the warmth of ordinary silk fabrics belongs to passive heat preservation, that is, the way of keeping warm that depends on the body's own temperature, and cannot produce heat by itself under the light, so it is mostly used in ordinary household life, while in polar regions, space, shallow seas and other harsher environments In the environment, the warmth of ordinary silk will also be greatly reduced.

At present, the existing improvement of silk properties is mostly limited to mechanical properties, and a lot of research has been done to improve the strength, toughness and other properties of silk, but there is still not much research on improving the warmth retention of silk fabrics. For example, Chinese Patent Publication No. CN104878467A discloses an aluminum oxide modified silk and a preparation method thereof. In the patent, the inventor added nano-aluminum oxide to the artificial feed of silkworms, and the silkworms absorbed aluminum oxide into the silk gland after eating, and then produced the silk containing aluminum oxide, which improved the toughness and strength of the silk. On the basis of the publication number CN102912470A, the researchers added graphene oxide solution to the regenerated silk fibroin solution, dried silk at room temperature, and then treated with ethanol-water mixture to improve the elongation of silk. rate, breaking strength and other properties. However, this spinning method is complicated in process, harsh in conditions and low in output, and is not suitable for mass production. Some researchers also added some minerals, pigments and other functional particles to the silkworm feed, and spun functional silk through the transformation of silkworms. These inventions all improve the toughness, strength and other properties of silk, but they are not involved in its warmth retention. Therefore, in order to obtain silk fabrics that can self-generate heat in harsher environments and have better thermal insulation properties and broaden their application range, it is necessary to modify silk for better use in aerospace (such as space suits), nanomaterials, Polar scientific research, marine scientific research, marine exploration, lifesaving and other fields.

SUMMARY OF THE INVENTION

Aiming at the problems existing in the prior art, the present invention provides a nano-tungsten trioxide feeding silkworm breeding method for preparing self-producing hot silk and its products. The production process is simple and feasible, the required equipment is cheap, the overall cost is low, and the cycle is relatively low. Short, the obtained functional silk has photothermal properties, can self-generate heat under weak light without damaging the original excellent quality of silk, which is convenient for mass production.

The present invention is achieved through the following technical solutions:

A kind of nanometer tungsten trioxide feeding silkworm breeding method for preparing self-producing hot silk, comprising the following steps,

Step 1, the silkworms are fed the silkworm feed without adding nano-tungsten trioxide from the first to the third instar;

Step 2, from the fourth instar, the compound feed added with a mass fraction of 1%-1.5% nano-tungsten trioxide aqueous solution, the mass ratio of the aqueous solution to the feed is 1: (20-25), and the nano-tungsten trioxide is absorbed by the silkworm into the silk gland;

In step 3, the compound feed is fed until the fifth instar, and the nano-tungsten trioxide entering the silk gland is finally combined with the nano-tungsten trioxide into the silk during the spinning process, until the upper cocoon forms, that is, the self-producing hot silk is obtained.

Preferably, the specific preparation process of the compound feed includes the following steps:

(1) Dissolving nano-tungsten trioxide in water to prepare an aqueous solution of nano-tungsten trioxide with a mass fraction of 1%-1.5%;

(2) uniformly spraying the prepared tungsten trioxide aqueous solution on the surface of silkworm feed to obtain compound feed.

Preferably, in step (1), the nano-tungsten trioxide aqueous solution with a mass fraction of 1%-1.5% is ultrasonically dispersed for at least 25 minutes, and the ultrasonic power is 250-300W to obtain a prepared nano-tungsten trioxide aqueous solution.

Preferably, the silkworm feed adopts fresh and tender mulberry leaves of different sizes: for feeding first-instar silkworms, take fresh and tender mulberry leaf filaments with a width of 5-6mm and a length of 1-2cm; for feeding second-instar silkworms, take a width of 6-7mm , fresh and tender mulberry leaf filaments with a length of 1-2cm; feeding the third instar silkworm, take the fresh tender mulberry leaf filament with a width of 7-9mm and a length of 1-2cm; feeding the fourth to fifth instar silkworm, take the spray mass fraction of 1%- Whole fresh and tender mulberry leaves in 1.5% tungsten trioxide aqueous solution were used as compound feed.

Preferably, it also includes the following steps of removing sericin:

(1) the silkworm cocoon is cut open to remove the inner silkworm chrysalis;

( ₂ ) Put the cocoons in a _Na2CO3 solution with a mass fraction of 1%-1.5% and boil for 25-30 minutes, the sericin is gradually hydrolyzed, and then repeatedly washed with deionized water until the degumming is completed;

(3) The degummed silk is placed in a cool place and air-dried naturally to obtain self-produced hot silk.

A self-produced hot silk is obtained by any one of the above-mentioned methods.

A self-produced thermal silk product, which is woven or woven from self-produced thermal silk.

Compared with the prior art, the present invention has the following beneficial technical effects:

In the invention, a certain mass fraction of nano-tungsten trioxide solution is sprayed on fresh mulberry leaves to feed silkworms, and the silkworms themselves absorb the nano-tungsten trioxide into the silk. The interaction of fibroin not only improves the toughness and strength of silk, but also makes it have excellent photothermal properties of tungsten trioxide. In the present invention, nano-tungsten trioxide is dissolved into silk by feeding, and the tungsten element is connected with the silk protein in a covalent bond, which improves the toughness of the silk; the tungsten element can form a hydrogen bond with the silk fibroin, which hinders its conformation. The higher the content of tungsten in silk, the stronger the barrier to the transition from the random conformation to the β-sheet conformation, which in turn destroys the silk structure and reduces the crystallinity.

Under the premise of not changing the original excellent quality of silk, the self-heating silk product produced by the invention has the characteristic of self-producing heat under illumination, and can self-produce heat in places with weak light. In aerospace, nanomaterials , polar scientific research, ocean exploration, lifesaving and other fields have potential application value.

Description of drawings

Fig. 1 is the photothermal curve diagram of nanometer tungsten trioxide in the present invention.

FIG. 2 is a working flow chart of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments, which are to explain rather than limit the present invention.

In Figure 1, the two curves are the photothermal curves of the aqueous solution of tungsten trioxide with a concentration of 500ug/ml under the irradiation of a 980nm laser with a power of 1W and 2W. Figure 1 shows that under 980nm laser irradiation, low-concentration tungsten trioxide aqueous solution can generate more heat, and the higher the laser power within a certain range, the higher the heat generation. On the one hand, it reflects the excellent photothermal properties of tungsten trioxide;

In Figure 2, the production and application process of the self-producing tungsten trioxide silk of the present invention is illustrated. It should be understood that the processes such as feeding, production, and application in the present invention are not limited to this. After the content, researchers in the field can make improvements to the present invention, and the equivalent forms thereof fall within the scope limited by the appended claims of the present application.

In Table 1 to Table 3, under the irradiation of 2w 980nm laser, the temperature of silk obtained without feeding, feeding with 1% tungsten trioxide feed, and feeding with 1.5% tungsten trioxide feed varies with Timetable. It further illustrates the excellent photothermal properties of tungsten trioxide silk compared to ordinary silk.

The present invention is a silkworm breeding method for self-producing thermal nano-tungsten trioxide functional silk. - Mulberry leaves in a 1.5% nanometer tungsten trioxide aqueous solution (fed to the fourth to fifth instars).

Among them, the feed needs to be cut into mulberry leaf silk of different sizes according to different silkworm ages. Feed the first-instar silkworms, and cut the fresh tender mulberry leaves into filaments with a width of 5-6mm and a length of 1-2cm; feeding the second-instar silkworms, cut the fresh and tender mulberry leaves into filaments with a width of 6-7mm and a length of 1-2cm; Feed the third instar silkworm, cut fresh tender mulberry leaves into filaments with a width of 7-9mm and a length of 1-2cm; feed the fourth to fifth instar silkworm, take the whole mulberry leaf sprayed with a mass fraction of 1%-1.5% tungsten trioxide aqueous solution That's it.

After the preparation of the nano-tungsten trioxide aqueous solution with a mass fraction of 1%-1.5%, ultrasonication is carried out for 30 minutes, and the power is 300W, in order to uniformly disperse the nano-tungsten trioxide particles. Among them, tungsten trioxide is extremely small in size, has good water solubility, and can be uniformly dispersed in water after ultrasonication. Through the absorption and transformation of silkworm, the tungsten trioxide in the silk is evenly distributed, and the photothermal effect is good, and its original characteristics such as air permeability and bulkiness are not affected.

For the functional silk obtained above, the concrete steps of removing sericin are as follows:

(1) the silkworm cocoon is cut open to remove the inner silkworm chrysalis;

(2) Put the cocoons in a Na2CO3 solution with a mass fraction of 1% and boil for 25-30 minutes, the sericin is gradually hydrolyzed, and then repeatedly washed with deionized water;

(3) place the silk that degumming completes to be placed in the shade and air-dry naturally;

Although sericin has little effect on the mechanical properties of silk, sericin will affect the silk's luster, air permeability, smoothness, feel and bring some difficulties to post-processing. Therefore, degumming must be carried out before weaving to obtain soft, loose and clean silk.

A self-producing thermal nanometer tungsten trioxide silk textile is woven from functional silk.

specific,

Example 1

The present invention is a silkworm breeding method for self-producing thermal nanometer tungsten trioxide functional silk,

First, the silkworm feed at each stage is prepared,

(1) Prepare an aqueous solution of nano-tungsten trioxide with a mass fraction of 1%, and then ultrasonicate for 30 minutes with a power of 300W, in order to disperse the nano-tungsten trioxide particles uniformly;

(2) The prepared tungsten trioxide solution is evenly sprayed on the surface of the cut mulberry leaves, collected and refrigerated so as to be taken at any time;

Then, during the feeding process of the silkworm, the tungsten trioxide is absorbed by the silkworm into the silk gland, and then the self-produced hot silk containing tungsten trioxide is produced;

Specifically, silkworms were fed fresh and tender mulberry leaves that were not sprayed with tungsten trioxide from the first to third instar years. From the fourth instar, they were fed fresh mulberry leaves sprayed with 1% tungsten trioxide aqueous solution. The mass ratio is 1:20 until cocooning.

For the functional silk obtained above, the concrete steps of removing sericin are as follows:

(1) the silkworm cocoon is cut open to remove the inner silkworm chrysalis;

(2) The cocoons were placed in a Na2CO3 solution with a mass fraction of 1% and boiled for 25 minutes, the sericin was gradually hydrolyzed, and then repeatedly washed with deionized water;

(3) place the silk that degumming completes to be placed in the shade and air-dry naturally;

The self-producing heat-producing functional silk thus obtained can be woven to obtain various self-producing heat-producing silk products, which are used in various fields.

As shown in Table 1, the photothermal data of silk was obtained by feeding 1% tungsten trioxide feed.

Laser irradiation time (S) Silk surface temperature (℃) 0 22.3 100 25.7 200 27.9 300 30.4 400 32.7 500 34.3 600 35.7

Example 2

The present invention is a silkworm breeding method for self-producing thermal nanometer tungsten trioxide functional silk,

First, the silkworm feed at each stage is prepared,

(1) Prepare an aqueous solution of nano-tungsten trioxide with a mass fraction of 1.5%, and then ultrasonicate for 25 minutes with a power of 250W, in order to disperse the nano-tungsten trioxide particles uniformly;

(2) The prepared tungsten trioxide solution is evenly sprayed on the surface of the cut mulberry leaves, collected and refrigerated so as to be taken at any time;

Then, during the feeding process of the silkworm, the tungsten trioxide is absorbed by the silkworm into the silk gland, and then the self-produced hot silk containing tungsten trioxide is produced;

Specifically: silkworms are fed fresh and tender mulberry leaves that are not sprayed with tungsten trioxide from the first to third instar years. From the fourth instar, they are fed fresh mulberry leaves sprayed with a 1.5% mass fraction of tungsten trioxide aqueous solution. The mass ratio is 1:25 until cocooning.

For the functional silk obtained above, the concrete steps of removing sericin are as follows:

(1) the silkworm cocoon is cut open to remove the inner silkworm chrysalis;

(2) Put the cocoons in a Na2CO3 solution with a mass fraction of 1.5% and boil for 30 minutes, the sericin is gradually hydrolyzed, and then repeatedly washed with deionized water;

(3) place the silk that degumming completes to be placed in the shade and air-dry naturally;

The self-producing heat-producing functional silk thus obtained can be woven to obtain various self-producing heat-producing silk products, which are used in various fields.

As shown in Table 2, the photothermal data of silk was obtained by feeding tungsten trioxide feed with a mass fraction of 1.5%.

Laser irradiation time (S) Silk surface temperature (℃) 0 22.3 100 25.9 200 28.2 300 30.7 400 33.4 500 35.6 600 36.5

Example 3

The present invention is a silkworm breeding method for self-producing thermal nanometer tungsten trioxide functional silk,

First, the silkworm feed at each stage is prepared,

(1) Prepare an aqueous solution of nano-tungsten trioxide with a mass fraction of 1.2%, and then ultrasonicate for 40 minutes with a power of 270W, in order to make the nano-tungsten trioxide particles evenly dispersed;

(2) The prepared tungsten trioxide solution is evenly sprayed on the surface of the cut mulberry leaves, collected and refrigerated so as to be taken at any time;

Then, during the feeding process of the silkworm, the tungsten trioxide is absorbed by the silkworm into the silk gland, and then the self-produced hot silk containing tungsten trioxide is produced;

Specifically, silkworms were fed fresh and tender mulberry leaves that were not sprayed with tungsten trioxide from the first to third instar years. From the fourth instar, they were fed fresh mulberry leaves sprayed with a 1.2% tungsten trioxide aqueous solution. The mass ratio is 1:23 until cocooning.

For the functional silk obtained above, the concrete steps of removing sericin are as follows:

(1) the silkworm cocoon is cut open to remove the inner silkworm chrysalis;

(2) The cocoons were boiled for 28 minutes in a Na2CO3 solution with a mass fraction of 1.3%, the sericin was gradually hydrolyzed, and then repeatedly washed with deionized water;

(3) place the silk that degumming completes to be placed in the shade and air-dry naturally;

The self-producing heat-producing functional silk thus obtained can be woven to obtain various self-producing heat-producing silk products, which are used in various fields.

Comparative Example

A silkworm breeding method for obtaining original silkworm silk, firstly preparing silkworm feed at various stages, specifically:

Cut fresh mulberry leaves of different sizes according to different silkworm ages (without sprinkling tungsten trioxide aqueous solution), collect and refrigerate so that they can be taken at any time;

After the silkworm passes through the stages of eggs, larvae, and pupa (divided into 5 instars), the silkworms form cocoons.

The above-mentioned original silk obtained, the concrete steps of described removing sericin are as follows:

(1) the silkworm cocoon is cut open to remove the inner silkworm chrysalis;

(2) Put the cocoons in a Na2CO3 solution with a mass fraction of 1% and boil for 25-30 minutes, the sericin is gradually hydrolyzed, and then repeatedly washed with deionized water;

(3) place the silk that degumming completes to be placed in the shade and air-dry naturally;

The silk thus obtained is woven to obtain various silk products.

As shown in Table 3, the photothermal data of silk was obtained from ordinary feed without tungsten trioxide.

Laser irradiation time (S) Silk surface temperature (℃) 0 22.3 100 23.4 200 24.2 300 24.7 400 25.0 500 25.3 600 25.8

Comparing the photothermal data of silk obtained by adding 1% and 1.5% tungsten trioxide aqueous solution feed without feeding, it shows that the silk obtained by feeding tungsten trioxide aqueous solution feed is better than that obtained without feeding tungsten trioxide aqueous solution. The obtained silk has a great improvement in the photothermal effect, and the silk obtained by feeding the feed with a mass fraction of 1.5% tungsten trioxide aqueous solution is more sensitive to light and heat than the silk obtained by feeding the feed with a mass fraction of 1% tungsten trioxide aqueous solution. The effect has been significantly improved.

The preparation of self-producing thermal tungsten trioxide functional silk of the present invention is that a certain mass fraction of tungsten trioxide aqueous solution is sprayed on the surface of fresh mulberry leaves fed by silkworms, and the tungsten trioxide is absorbed into the silk glands by the silkworms during the feeding process. In the spinning process, tungsten trioxide is incorporated into the silk to obtain functional silk with excellent photothermal properties;

It generally takes 27 days from hatching to cocooning in silkworms (divided into five instars). The first to third instar silkworms are fed with fresh and tender mulberry leaves without nano-tungsten trioxide added. %-1.5% of fresh mulberry leaves in nano-tungsten trioxide aqueous solution, until the end of fifth instar, silkworms will cocoon. From the first to third instar silkworms, the silk glands are immature, and feeding mulberry leaves containing tungsten trioxide is not conducive to the growth and development of silkworms, and the content of tungsten trioxide entering the silk glands at this stage is very small. After the fourth instar, the silk glands mature, and the synthesis of silk protein is mainly in the fourth to fifth instar. Therefore, feeding fresh mulberry leaves containing nano-tungsten trioxide during this period can obtain functional silk rich in tungsten trioxide. After further degumming and weaving, silk products that can generate heat by themselves under light are obtained, which are used in various fields.

However, feeding with high content of tungsten is not conducive to the growth and development of silkworms, and feeding with low content of tungsten cannot guarantee the content of silk, so it is necessary to select an aqueous solution of tungsten trioxide with a suitable mass fraction. Experiments found that the content of tungsten trioxide in silk was too low when 0.5% tungsten trioxide aqueous solution was used. , is wasted in the subsequent degumming process. The growth and development of silkworms were affected by feeding with 2% tungsten trioxide aqueous solution. Silkworms appear partially dead, resulting in lower silk production. Therefore, the present invention selects an aqueous solution of tungsten trioxide with a mass fraction of 1% to 1.5%, and experiments show that the normal feeding, growth and cocoon formation of silkworms are not affected.

As a metal oxide, tungsten trioxide has stable chemical properties and is difficult to react with solvents such as acid and alkali at room temperature. It is often used in the manufacture of pure tungsten products, tungsten wires, tungsten electrodes, and anti-corrosion coatings. Recently, studies have found that tungsten trioxide has excellent photothermal effect, which is more excellent than nanomaterials such as carbon nanotubes. Therefore, the present invention utilizes nano-tungsten trioxide to modify silk to obtain functional silk that can self-generate heat under illumination, and is further applied in various fields.

Claims (3)

1. A nano tungsten trioxide feeding silkworm rearing method for preparing self-heating silk is characterized by comprising the following steps,

step 1, feeding a silkworm feed which is not added with nano tungsten trioxide by silkworms in one to three ages;

feeding a compound feed added with a nano tungsten trioxide aqueous solution with the mass fraction of 1% -1.5% from the fourth instar, wherein the mass ratio of the aqueous solution to the compound feed is 1 (20-25), and silkworms absorb the nano tungsten trioxide to enter silk glands;

step 3, feeding the composite feed to the fifth instar, and finally combining the nano tungsten trioxide entering the silk gland into the silk in the spinning process until cocooning and cocooning are performed, so that the self-produced hot silk is obtained;

the specific preparation process of the compound feed comprises the following steps:

(1) dissolving nano tungsten trioxide in water to prepare a nano tungsten trioxide aqueous solution with the mass fraction of 1% -1.5%;

(2) uniformly spraying the prepared nano tungsten trioxide aqueous solution on the surface of the silkworm feed to obtain a compound feed;

in the step (1), performing ultrasonic dispersion on a nano tungsten trioxide aqueous solution with the mass fraction of 1% -1.5% for at least 25min, wherein the ultrasonic power is 250-300W, so as to obtain a prepared nano tungsten trioxide aqueous solution;

the silkworm feed adopts fresh tender mulberry leaves with different sizes: feeding one-year-old silkworm, and taking fresh tender folium Mori filaments with width of 5-6mm and length of 1-2 cm; feeding second-instar silkworm, and taking fresh tender folium Mori filament with width of 6-7mm and length of 1-2 cm; feeding three-year-old silkworm, and taking fresh tender folium Mori filament with width of 7-9mm and length of 1-2 cm; feeding four to five-instar silkworms, and taking a whole piece of fresh tender mulberry leaves sprayed with a nano tungsten trioxide aqueous solution with the mass fraction of 1 to 1.5 percent as a compound feed;

the nano tungsten trioxide enters silk, tungsten elements in the nano tungsten trioxide interact with fibroin in a hydrogen bond and chelation mode, the tungsten elements are connected with the fibroin in a covalent bond mode, and the tungsten elements and the fibroin form hydrogen bonds.

2. The method for feeding silkworm to prepare self-heating silk by using nano tungsten trioxide as claimed in claim 1, further comprising the following steps of:

(1) cutting silkworm cocoon to remove silkworm pupa;

(2) placing the silkworm cocoon in Na with the mass fraction of 1-1.5%₂CO₃Boiling the solution for 25-30 minutes, gradually hydrolyzing sericin, and then repeatedly cleaning with deionized water until degumming is completed;

(3) and (3) placing the degummed silk in a shade place for natural air drying to obtain the self-produced hot silk.

3. A self-heating silk obtained by the silkworm breeding method according to any one of claims 1 to 2.

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