CN110767883B

CN110767883B - Modified fiber, preparation method and application

Info

Publication number: CN110767883B
Application number: CN201910588802.1A
Authority: CN
Inventors: 罗宝林
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-07-02
Filing date: 2019-07-02
Publication date: 2023-07-04
Anticipated expiration: 2039-07-02
Also published as: CN110767883A

Abstract

The invention relates to modified fibers, a preparation method and application thereof. Mixing the raw materials, water and substances containing metal complex ions, controlling the temperature to be 40-100 ℃ under neutral or alkaline conditions, and stirring for 5-24 hours to obtain the modified fiber product. The modified fiber of the invention has strong hydrophobicity, and the fiber is natural brown black, and can be used for producing sofa paper, leather shoes paper, liquid packaging paper and opaque curtain paper which need strong water resistance. The fiber contains a metal compound with stable performance, greatly improves the strength and stiffness, and can be used for producing medical ointment medical paper, hard paper black paperboard, sand paper and special packaging paper; in addition, the long-chain fiber contains metal oxide with very high specific content of lithium ions, and can form stable lamellar or tubular nano carbon-metal compound composite material by a vapor deposition method, so that the nano carbon-metal compound composite material can be used as a negative electrode of a lithium ion battery, and the specific capacity and the rate capability of the battery can be greatly improved.

Description

Modified fiber, preparation method and application

Technical Field

The invention relates to modified fibers, a preparation method and application thereof, and belongs to the field of materials.

Background

At present, the technology is rapidly developed, the conditions of discipline crossing, application crossing and field crossing are more and more in the new material field, and the material provided by the invention can be used in the special paper manufacturing field, and can be further subjected to advanced treatment and also be applied to the battery industry.

Today, the technology of pulping and papermaking is mature, and the application of common paper is basically stopped. The appearance of new technology, new materials and new application enables the special paper to keep the situation of high-speed development all the time, and the added value of the product is very high. The manufacture of specialty papers is largely dependent on the material technology, and the specialty fibers of the present invention have made a breakthrough in this situation.

In some special application fields, because fiber raw materials are easy to obtain and environment-friendly, many companies want to replace plastic products, animal leather and artificial leather with paper products, but the structural characteristics of fibers rich in hydrophilic hydroxyl groups determine that the water resistance is poor, the wet strength is low, and the dry strength and stiffness are insufficient, which afflicts many industry companies, such as sofa surface paper, shoe surface paper, liquid packaging paper, opaque curtain paper, medical plaster paper, hard black paperboard, sand paper, special packaging paper and the like, which are required to be strong in water resistance and high in strength.

Today, the rapid development of electronic technology and artificial intelligence, all of which suffer from a bottleneck, namely battery technology.

Compared with electronic products which are updated every year and rapidly developed, the battery technology is like a snail and slowly advances, and the specific capacity, the charging time and the cycle times are not kept pace with the development pace of the electronic technology, so that a short board for restricting the development of the electronic technology is formed.

From the new energy automobile, the short endurance mileage and the too long charging time are all the time bottlenecks which plague the development of the new energy automobile; there are also unmanned aircraft, and are also subject to battery technology.

In summary, the development of the battery technology is slow in comparison with the current day of the rapid development of semiconductors, software and electronic technologies. For the rechargeable battery used in the current electronic products, the lithium ion battery accounts for more than 90%, the positive electrode of the lithium ion battery is provided with lithium metal, lithium alloy and ternary lithium, and the negative electrode of the lithium ion battery is also a lot, but the most widely used lithium ion battery is also natural graphite, artificial graphite and mesophase carbon microspheres, and the lithium ion battery accounts for 55%, 35% and 8% respectively; the specific capacity of the materials used as the negative electrode of the lithium ion battery is difficult to break through the theoretical limit capacity 372mAh/g of carbon, and the charging time is difficult to shorten due to the characteristics of the materials.

Disclosure of Invention

Aiming at the defects of the prior art, one of the purposes of the invention is to provide a modified fiber and a preparation method thereof, so as to modify lignin and/or other fiber substances to obtain a coordination compound with strong hydrophobicity and stable performance. The second purpose of the invention is to provide the application of the modified fiber in the papermaking field or in the preparation of lithium ion battery anode materials.

In order to solve the technical problems, the technical scheme of the invention is as follows:

the preparation method of the modified fiber comprises the steps of mixing raw materials, water and a substance containing metal complex ions, and stirring for 5-24 hours, preferably 5-16 hours under neutral or alkaline conditions at a temperature of 40-100 ℃, preferably 50-80 ℃ to obtain a modified fiber product;

wherein the raw material comprises at least one of water-insoluble lignin, bamboo pulp, wood pulp, cotton pulp, dissolving pulp and viscose fiber;

the substance containing metal complex ions comprises at least one of permanganate and ferrate.

Further, the mass ratio of the raw materials to the water to the substances containing the metal complex ions is 10:20-500:1-10. Preferably, the mass ratio of the raw material to the purified water is 1:10-20, preferably, the mass ratio of the raw material to the substance containing the complex ion is 2-3:1.

Preferably, the feedstock comprises 1-100 parts wood pulp and 1-100 parts lignin, further preferably, the feedstock comprises 60 parts wood pulp and 40 parts lignin.

Further, the water is purified water.

Further, the permanganate comprises at least one of potassium permanganate, sodium permanganate and ammonium permanganate; the ferrate comprises at least one of potassium ferrate, sodium ferrate, and ammonium ferrate.

Further, the substances containing metal complex ions comprise ammonium permanganate, potassium permanganate and potassium ferrate, and the mass ratio of the ammonium permanganate to the potassium ferrate is 1-100:1-100:1-100, generally 20-80:10-70:10-70, preferably 40:30:30.

Potassium permanganate (KMnO) ₄ ) Or potassium ferrate (K) ₂ FeO ₄ )、NH ₄ MnO ₄ The substances have weak oxidizing property under neutral or alkaline environment, but can be used as acceptors of coordination compounds, mn-O or Fe-O bonds have poor stability, and high-valence manganese ions or high-valence iron ions provide empty electron orbitals as acceptors。

Further, the stirring rate is 200 to 6000 rpm, preferably 300 to 1000 rpm. Stirring to make the raw materials and the substances containing metal complex ions contact more fully, wherein an emulsifying head or a dispersing head can be selected by a stirrer.

Modified fibers made by the preparation method described above.

The modified fiber prepared by the preparation method is applied to papermaking.

Further, the modified fiber is used in the papermaking field after being subjected to dehydration treatment or pulp treatment.

Further, the solution produced in the preparation of the modified fiber is directly centrifugally dehydrated to obtain the special fiber with the water content of 70-80 wt%.

Further, the modified fiber is mixed with water to prepare modified fiber slurry with the concentration of 1-2wt%, and then the modified fiber slurry is made into a slurry board with the water content of less than 5wt% by a board machine.

The modified fiber prepared by the preparation method is applied to the preparation of the lithium ion battery anode material.

Further, the modified fiber product is subjected to purification treatment, and then the purified modified fiber product is prepared into the nano carbon-metal compound composite material by a vapor deposition method. Further, the separated high-purity modified fiber is mixed with an organic or inorganic compound containing carbon and nitrogen, the mixture is placed into a high-temperature reaction furnace, inert gas is introduced, the temperature is increased, the carbon and nitrogen compound sublimates at high temperature, and carbon atoms are deposited in a region taking the metal compound as a center, so that a layered or tubular nano carbon-metal compound composite material is formed.

In this way, the modified fiber is used as a base material, and a layered nano carbon-metal compound composite material or a carbon nano tube and metal compound composite material containing transition metal or metal oxide is synthesized by a vapor deposition method with a carbon-nitrogen compound to be used as a novel lithium ion anode material. The lithium ion battery has high specific capacity, can be charged quickly, has long cycle life, can completely replace a graphite cathode, and has great significance and good prospect.

Further, the purification treatment includes at least one of ion exchange treatment, washing.

Further, one of the methods of purifying the modified fiber product comprises the steps of:

1. exchange of hydrogen ions with metal cations

After the reaction is stopped, the liquid is pumped into a cation exchanger, and metal cations (such as potassium ions) in the solution in the exchanger are exchanged with hydrogen ions in the acid cation exchange resin, the metal cations are adsorbed by the acid cation exchange resin, the hydrogen ions are replaced, and the hydrogen ions are in contact with OH in the solution ^- Water is produced. The metal cations in the solution are removed.

2. Flocculation

Adding an organic flocculant PAM into the solution for removing the metal cations, stirring to form alum blossom, and standing for layering.

The flocculant in the invention is cationic, anionic or nonionic PAM; nonionic PAM is preferred.

3. Filtration

The flocculated reactants are filtered using a 80-1000 mesh screen, preferably a 100-400 mesh screen. And filtering to obtain the purified modified fiber.

Further, another method of purifying the modified fiber product comprises the steps of:

1. flocculation

After the coordination reaction is completed, cooling to room temperature, adding a flocculating agent, stirring to form alum blossom, and standing for layering.

The flocculant is cation, anion or nonionic PAM; nonionic PAM is preferred.

2. Filtration

The reaction flocculation is filtered using a 80-1000 mesh screen, preferably a 100-400 mesh screen.

3. Washing

Mixing the filtered reaction flocs with water in a mass ratio of 1:3-30, preferably in a ratio of 1:3-1:10, and the reaction was filtered off.

The washing was repeated at least once according to the above procedure. Obtaining the modified fiber product after high purification.

In the invention, lignin or fiber substances in the raw materials have large molecular structure size, are not dispersed in water, cannot form suspension, have good drainage property, are easy to separate from water, have lone pair electrons contained in oxygen atoms in exposed hydroxyl groups, and have poor O-H bond stability. The water is used as a reaction medium, and the temperature is controlled to be 40-100 ℃, so that the coordination reaction can be promoted. The reaction characteristics are mainly coordination reaction, the reaction is mild, a certain reaction time is needed, and the applicant repeatedly researches and discovers that the reaction time is controlled to be 5-24 hours, and the effect is good. Through stirring operation with a certain speed, the material and the substance containing complex ions can be adequately mixed to fully react, and the modification effect is improved.

The modified fiber of the invention has no exposed hydroxyl and contains metal or metal oxide, the inventor defines the modified fiber as a special fiber material SF (Special Fiber), the special fiber material SF can be used in the field of special paper making, the application range is wide, the market is clear, the strength and the water resistance of the existing special paper can be greatly improved, and the prospect is very wide, for example: can be used for producing sofa paper, leather shoes paper, liquid packaging paper, opaque curtain paper, medical plaster paper, hard black paperboard, sand paper, special packaging paper and the like which need strong water resistance.

The special fiber SF produced in the invention has extremely strong water resistance because of the coordination reaction, no exposed hydroxyl is on the surface, and meanwhile, the long-chain structure contains stable coordination metal or metal oxide, so that the strength and stiffness of the special fiber SF are greatly improved, and the special fiber SF can be matched in a certain proportion for use in wood fiber, thus solving the current puzzlement, and having great significance.

The special fiber contains transition metal or metal compound with high lithium ion specific capacity and has stable long-chain structure, and can be used as a lithium ion battery anode material after further treatment.

The special fiber has a stable long-chain structure, contains metal or metal oxide with extremely high specific capacity of lithium ions, takes the metal or metal oxide as a base Material, can generate a layered nano carbon-metal (metal oxide) or tubular nano carbon-metal compound (metal oxide) composite Material (BM: battery Material) through further treatment of a vapor deposition method and the like, and has the characteristics of high specific capacity (more than 20 percent of a graphite negative electrode), short charging time (90 s) and long service life, and is used in the negative electrode of a lithium ion Battery to replace the existing graphite or modified graphite or carbon nano balls or carbon nano tube negative electrode Material. The specific capacity of the existing lithium ion battery is improved from 340mAh/g-350mAh/g to 400mAh/g-450mAh/g; the charging time is shortened from the current several hours to 30s-120s; the cycle times reach 800-1200 times; does not self-ignite or explode when charged with high current. Can be widely applied to industries using lithium ion batteries such as mobile phones, new energy automobiles and the like, and has very broad product prospect.

Lignin or fiber has abundant hydroxyl groups, which determine that the lignin or fiber has hydrophilicity; however, benzene ring structures of lignin and beta-type long-chain structures of fibers with abundant hydrogen bonds, and meanwhile, due to the van der Waals force and the hydrogen bond action among molecules, the molecules have crystallization areas, and the exposed hydroxyl groups are not much, so that the lignin and the fiber are insoluble in water; the critical property of the fiber length reaching 0.8mm-3.5mm, such large size that it cannot be dispersed in water or exist in suspended state, determines that the reaction product is easy to separate from water and easily remove other ions dissolved in water, has extremely low separation cost when the reactants are separated, and ensures the purity of the reaction product.

Ammonium permanganate, potassium ferrate and the like contain complex ions (such as MnO ₄ ^- 、FeO ₄ ^2- ) And the oxidation property of the material is extremely low in a neutral or alkaline environment, and is insufficient for breaking the glycoside bond of the fiber molecule, so that the strength of the fiber is ensured. These high valence metal ions can provide an empty orbit as a coordination acceptor, and form stable coordination compounds with oxygen atoms in hydroxyl groups containing lone pair electrons under neutral or alkaline environment, and the coordination bonds are stronger and more stable than Mn-O bonds and Fe-O bonds according to the coordination constant calculation theory.

In this reaction, for example, mnO ₄ ^- 、FeO ₄ ^2- The manganese ion is +7, the iron ion is +6, the oxygen atom in the fiber OH-has lone pair electrons, mnO ₄ ^- 、FeO ₄ ^2- Form stable coordination bond with the high valence Mn ion, fe ion and oxygen atom with lone pair electron in hydroxyl OH to be complexly adsorbed on fiber, and meanwhile, because the stable coordination compound occupies Mn ⁷⁺ Or Fe (Fe) ⁶⁺ The empty orbit of (2) leads Mn-O bond and Fe-O bond with unstable structure to be broken, and divalent oxygen ion O is dissociated ^2- Group MnO ₄ ^- Becomes MnO ₃ ，FeO ₄ ^2- Become FeO ₃ The method comprises the steps of carrying out a first treatment on the surface of the At this time because the oxygen atom in OH hydroxyl group is based on group MnO ₃ The manganese ions in the catalyst form a stable complex, so that O-H bonds which are easy to break originally are thoroughly broken, and H+ ions are dissociated; mnO (MnO) ₄ ^- O of medium dissociation ^2- H dissociated from OH ⁺ The ions combine to form OH-; hydroxide ions and KMnO ₄ K in bond ⁺ Reacting to generate KOH; in further heating, the group MnO ₃ The other two oxygen atoms are separated from Mn-O and become Mn-O bond, and the whole main reaction process is completed. The fiber turns brown due to complexation adsorption of MnO and the potassium permanganate solution turns colorless and transparent KOH. The pH value of the solution is changed from 6.5 to 7 to 8.5 to 9, feO ₄ ^2- Ions and MnO ₄ ^- The reaction mechanism is the same. The reaction formula is as follows:

R-OH+MnO ₄ ^- →R-O-MnO ₃ +O ^2- +H ^- →R-O-MnO ₃ +OH ^-

OH ^- +K ⁺ →KOH

further heating, part of R-O-MnO ₃ Middle MnO ₃ Is broken to release oxygen to form a more stable coordination compound R-O-MnO

R-O-MnO ₃ (heating) →R-O-MnO+O ₂

At the same time, there are two side reactions occurring during this reaction:

side reaction one: hemicellulose is contained in the fiber or lignin, and is easily hydrolyzed into formic acid or acetic acid in hot water under the condition that metal ions are used as a catalyst, and the formic acid or the acetic acid provides an acidic environment to promote the hemicellulose to be further hydrolyzed to generate more formic acid or acetic acid, and the formic acid or the acetic acid reacts with potassium hydroxide to generate potassium formate or potassium acetate and water.

Side reaction one:

HCOOH+KOH→HCOOK+H ₂ O

CH ₃ COOH+KOH→CH ₃ COOK+H ₂ O

secondary reaction II: the potassium permanganate is heated for a long time to generate potassium manganate, manganese dioxide and oxygen, and the potassium manganate is subjected to disproportionation reaction under the weak alkaline condition to generate potassium permanganate, manganese dioxide and potassium hydroxide.

Secondary reaction II:

2KMnO ₄ (sufficient heating) →K ₂ MnO ₄ +MnO ₂ +O ₂

3K ₂ MnO ₄ +2H ₂ O→2KMnO ₄ +MnO ₂ +4KOH

The modified fiber is a special fiber with a long chain-shaped metal compound, the fiber length is 0.8-3.5 mm, because the lone pair electron of the oxygen atom in the exposed hydroxyl forms a stable coordination bond with the metal compound group with high complexing performance, the fiber has a long chain structure without the exposed hydroxyl basically, and the special fiber with the complexing adsorption metal compound has the following characteristics:

1. the fiber is very hydrophobic and is natural brown-black, and can be used for producing sofa paper, leather shoes paper, liquid packaging paper and opaque curtain paper with strong water resistance.

2. The fiber contains a metal compound with stable performance, greatly improves the strength and the stiffness, and can be used for producing medical ointment medical paper, hard paper black paperboard, sand paper and special packaging paper.

3. The long-chain fiber contains metal oxide with very high content of lithium ions, the metal oxide can be taken as a base material, carbon atoms are deposited around the metal atoms by taking the metal atoms as cores through a method of vapor deposition at high temperature by mixing carbon-nitrogen-containing compounds, the carbon atoms are reconstructed and combined with the metal atoms through chemical bonds, and a stable lamellar or tubular nano carbon-metal compound composite material is formed, and can replace graphite to be taken as a negative electrode of a lithium ion battery, so that the specific capacity and the rate performance of the battery can be greatly improved.

Drawings

FIG. 1 is an infrared plot (top) and matching plot (bottom, dissolving wood pulp) of the lower layer reactant as received in example five.

Fig. 2 is an XRD pattern of the relevant sample in example five: the lower reactant (upper), the lower reactant (middle) after washing with chloroform and the dissolving wood pulp (lower).

FIG. 3 shows Py-GCMS analysis patterns, lower layer reactant (upper) and standard pattern (lower).

Fig. 4 is an SEM image of the underlying reactant as received at 500 x magnification.

FIG. 5 is an SEM-EDS elemental profile of the underlying reactant as it is at 500 x magnification.

Fig. 6 is an EDS face scan of each element with the underlying reactant as it is at 500 x magnification.

Fig. 7 is an EDS diagram of the square box area of fig. 4.

Fig. 8 is an SEM image of the lower layer reactant at 500 x magnification after multiple water washes as is.

FIG. 9 shows the SEM-EDS elemental distribution of the lower layer reactant after multiple water washes as received at 500 x magnification.

Fig. 10 is an EDS face scan of each element at 500 x magnification after multiple water washes of the lower layer reactant as is.

Fig. 11 is an EDS diagram of the square box area of fig. 8.

Detailed Description

The present invention will be described in detail with reference to examples.

Examples of material preparation:

example one: adding lignin 100KG, purified water 870KG and potassium permanganate 30KG into a 1-ton reaction kettle, adding purified water 870KG, then adding 30KG potassium permanganate, stirring and heating to 70 ℃, preserving heat and reacting for 5 hours, and cooling to room temperature. Then 500 liters of the reaction solution was taken and fed into a centrifuge for dehydration to obtain a reactant SF1. And taking 500 liters of reaction solution, removing potassium ions in the reaction solution by a multiple-time washing method to obtain an intermediate product KF1, mixing the KF1 with ammonium carbonate or melamine, and sending the mixture into a high-temperature reaction furnace, and preparing the layered or tubular nano carbon-metal BM1 serving as a negative electrode of a battery material by using a vapor deposition method.

Example two: adding lignin 50KG, wood pulp 50KG, purified water 870KG and potassium permanganate 30KG into a 1-ton reaction kettle, adding purified water 870KG, adding 30KG potassium permanganate, stirring and heating to 70 ℃, preserving heat and reacting for 5 hours, and cooling to room temperature. Then 500 liters of the reaction solution is taken and sent into a centrifuge for dehydration, and the special fiber SF2 for papermaking is obtained. And (3) taking 500 liters of reaction solution, removing potassium ions in the reaction solution by an ion exchange method or a multiple-time washing method to obtain special fibers KF2, mixing KF2 with ammonium carbonate or melamine, and sending the mixture into a high-temperature reaction furnace, and preparing layered or tubular nano carbon-metal or metal oxide BM2 serving as a negative electrode of a battery material by a vapor deposition method.

Example three: adding lignin 75KG, wood pulp 25 KG, purified water 870KG and potassium permanganate 30KG into a 1-ton reaction kettle, adding purified water 870KG, adding 30KG potassium permanganate, stirring and heating to 70 ℃, preserving heat and reacting for 5 hours, and cooling to room temperature. Then 500 liters of reaction solution is taken and sent into a centrifugal machine for dehydration, and the special fiber SF3 for papermaking is obtained. And (3) taking 500 liters of reaction solution, removing potassium ions in the reaction solution by an ion exchange method or a multiple-time washing method to obtain special fibers KF3, mixing KF3 with ammonium carbonate or melamine, sending the mixture into a high-temperature reaction furnace, and preparing layered or tubular nano carbon-metal or metal oxide BM3 serving as a negative electrode of a battery material by a vapor deposition method.

Example four: taking 100KG of wood pulp, 870KG of purified water and 30KG of potassium permanganate, adding the wood pulp into a reaction kettle of 1 ton, adding 870KG of purified water, then adding 30KG of potassium permanganate, stirring and heating to 70 ℃, preserving heat and reacting for 5 hours, and cooling to room temperature. Then 500 liters of reaction solution is taken and sent into a centrifugal machine for dehydration, and the special fiber SF4 for papermaking is obtained. And (3) taking 500 liters of reaction solution, removing potassium ions in the reaction solution by an ion exchange method or a multiple-time washing method to obtain special fibers KF4, mixing KF4 with ammonium carbonate or melamine, and sending the mixture into a high-temperature reaction furnace, and preparing layered or tubular nano carbon-metal or metal oxide BM4 serving as a negative electrode of a battery material by a vapor deposition method.

Example five

The fourth example was repeated, instead of using dissolving wood pulp, the mass ratio of dissolving wood pulp to potassium permanganate was controlled to 3:1, and supernatant and lower reactant were obtained, the contents of each component of the supernatant and lower reactant being shown in tables 1 and 2, respectively.

TABLE 1 analysis of supernatant composition

Component numbering	Component name	Mass content/%	Commonly known as/brand/CAS No.
				1	Potassium hydroxide	～0.1-0.3	1310-58-3
2	Fiber segment	～0.02-0.04	/
				3	Potassium formate	～0.5-0.7	590-29-4
4	Water and its preparation method	～98.7-99.7	/

TABLE 2 analysis of lower reactant composition

Component numbering	Component name	Mass content/%	Commonly known as/brand/CAS No.
				1	Modified fiber	～91.5-92.5	/
2	Potassium formate	～2.8-3.8	590-29-4
				3	Potassium acetate	～1.0-2.0	127-08-2
4	Manganese dioxide	～3.1-4.1	1313-13-9

From the above table, the primary reaction produced modified fiber and potassium hydroxide, the secondary reaction produced potassium formate and potassium acetate, and the secondary reaction produced manganese dioxide, which precipitated and adsorbed on the fiber.

As can be seen from fig. 1, the fibers chemically react with potassium permanganate.

As can be seen from fig. 2, the crystalline form of the modified fibers was unchanged before and after chloroform washing of the dissolving wood pulp, and the crystalline form was significantly changed compared to the fibrils, indicating the formation of new compounds.

As can be seen from fig. 3, the combination of manganese ions and oxygen ions is as follows: C-O-Mn-O-C-, proves that the manganese ions in the MnO and the oxygen atoms in the hydroxyl groups of the fibers have coordination reaction, O-H bonds are broken, and meanwhile, the oxygen atoms in the MnO and the C of the fibers form weak O-C bonds.

It is demonstrated below that manganese dioxide does not react with the fibers but is adsorbed on the fibers in a precipitated manner.

Fig. 4 is an SEM image of the underlying reactant as received at 500 x magnification. FIG. 5 is an SEM-EDS elemental profile of the underlying reactant as it is at 500 x magnification. Fig. 6 is an EDS face scan of each element with the underlying reactant as it is at 500 x magnification. Fig. 7 is an EDS diagram of the square box area of fig. 4. Table 3 shows EDS detection results for the square area in fig. 4.

TABLE 3 Table 3

Fig. 8 is an SEM image of the lower layer reactant at 500 x magnification after multiple water washes as is. FIG. 9 shows the SEM-EDS elemental distribution of the lower layer reactant after multiple water washes as received at 500 x magnification. Fig. 10 is an EDS face scan of each element at 500 x magnification after multiple water washes of the lower layer reactant as is. Fig. 11 is an EDS diagram of the square box area of fig. 8. Table 4 shows EDS detection results for the square area in fig. 8.

TABLE 4 Table 4

From the comparison of the above detection data, the normalized mass of the manganese element after washing is reduced from 12.25% to 8.53%, and the normalized mass of the potassium element is reduced from 2.11% to 0.46%.

In the composition analysis table, mnO in the reactant ₂ The content of (3.1) to (4.1), the MnO ₂ Is removed in a plurality of washes. Therefore, this department of MnO ₂ Not the reactant of potassium permanganate and fiber, but the product of potassium permanganate thermal decomposition and disproportionation reaction of potassium manganate.

Therefore, the potassium permanganate and the hydroxyl groups of the fibers undergo a coordination reaction to generate new modified fibers.

Material application instance data

Performance index as raw material of special paper

The dry and wet strength and the water resistance of the water-resistant base paper 100wt% of the wood fiber, the special SF fiber 10wt% of the wood fiber, the improved paper 50wt% of the special SF fiber 50wt% of the wood fiber, and the reinforced paper 50wt% of the artificial leather, which were manufactured by the same process, respectively, were compared, and the specific results are shown in Table 5.

TABLE 5

The data show that according to the same process, a certain amount of special fibers are doped into the wood fibers, so that the water resistance is greatly enhanced, and the wet strength is greatly improved; when the blending amount reaches a certain proportion, the leather is basically similar to leather in terms of strength and water resistance. This allows the manufacture of many papers for special applications and can replace artificial leather or animal leather in many applications.

As a performance index of a lithium battery cathode material

And after the obtained final product is crushed, respectively taking the crushed product as a negative electrode material to replace natural graphite or artificial graphite, and coating the negative electrode of the lithium ion battery according to the national standard. The product performance index was detected as shown in table 6:

TABLE 6

The material is far superior to graphite cathode in specific capacity and charging time, and the battery cycle times representing service life are also superior to graphite. Is a good substitute for graphite and has very wide application prospect.

In conclusion, the natural lignin, bamboo pulp, wood pulp, cotton pulp, dissolving pulp and viscose are insoluble in water, and because the natural lignin, bamboo pulp, wood pulp, cotton pulp, dissolving pulp and viscose contain hydroxyl exposed outside, the natural lignin, bamboo pulp, wood pulp, cotton pulp and viscose have strong water absorption and good water filtering performance, and are easy to separate from water after being made into materials. The invention takes one or the mixture of the products according to a certain proportion as raw material (A for short), adds pure water, then adds potassium permanganate (KMnO 4), ammonium permanganate and potassium ferrate (MnO) under neutral condition ₄ ^- 、FeO ₄ ^2- ) And substances containing complex ions with high activity. MnO under neutral condition ₄ ^- 、FeO ₄ ^2- These ions are also very weak in oxidizing property and cannot break the long-chain glycosidic bond structure of the fiber, but these high-valence metal ions have empty electron orbitals and can form acceptors of coordination compounds. The substance A is insoluble in water, but has hydrogen bond and hydroxyl group exposed outside simultaneously, while oxygen atom in the hydroxyl group contains lone pair electrons, in the hydroxyl group structure, the-O-H-bond is weaker and is easy to break, and the lone pair electrons of the oxygen atom are easy to be combined with MnO with empty orbitals ₄ ^- 、FeO ₄ ^2- Mn in (b) ⁷⁺ 、Fe ⁶ ⁺ Forming a stable coordination compound (complex) to be bonded to the fiber; then hydrogen ion H+ in the O-H bond with weaker bond energy is dissociated to form a bond with MnO ₄ ^- 、FeO ₄ ^2- And generating OH-with the dissociated divalent oxygen ion, and generating alkali with potassium ion or ammonium ion. Thereby forming a long chain type without exposed hydroxyl groupWith a macromolecular structure of metal oxide, lignin-metal oxide or fiber-metal oxide, we call SF (Special Fiber). This material, because of the substitution of hydroxyl groups, has extremely high water resistance, and because of the presence of metal oxides, has very high hardness and stiffness, and can be used for manufacturing specialty papers, such as: liquid bag packaging paper, sand paper, sofa leather, paper leather shoes, black paperboard, medical plaster paper and the like; the material contains metal oxide in long carbon chain structure, and the specific capacity of the transition metal oxide to lithium ion is very high, and after further advanced treatment, lamellar nano carbon or nano carbon tube BM (Battery Material) containing metal oxide can be generated, and can be used as a negative electrode of a lithium ion battery instead of graphite material.

The foregoing examples are set forth in order to provide a more thorough description of the present invention, and are not intended to limit the scope of the invention, since modifications of the invention in various equivalent forms will occur to those skilled in the art upon reading the present invention, and are within the scope of the invention as defined in the appended claims.

Claims

1. The preparation method of the modified fiber is characterized in that raw materials, water and substances containing metal complex ions are mixed, the temperature is controlled to be 40-80 ℃ under neutral or alkaline conditions, and the mixture is stirred for 5-24 hours to obtain a modified fiber product;

wherein the raw material is at least one of water-insoluble lignin, bamboo pulp, wood pulp, cotton pulp, dissolving pulp and viscose fiber;

the substance containing metal complex ions is at least one of permanganate and ferrate; the mass ratio of the raw materials to the water to the substances containing the metal complex ions is 10:20-500:1-10; the permanganate comprises at least one of potassium permanganate, sodium permanganate and ammonium permanganate; the ferrate comprises at least one of potassium ferrate, sodium ferrate, and ammonium ferrate.

2. The preparation method according to claim 1, wherein the substance containing metal complex ions comprises ammonium permanganate, potassium permanganate and potassium ferrate in a mass ratio of 1-100:1-100:1-100.

3. The preparation method according to claim 2, wherein the mass ratio of the ammonium permanganate, the potassium permanganate and the potassium ferrate is 20-80:10-70:10-70.

4. A method according to any one of claims 1 to 3, wherein the stirring rate is 200 to 6000 rpm.

5. The process according to claim 4, wherein the stirring rate is 300 to 1000 rpm.

6. Modified fiber, characterized in that it is produced by the production method according to any one of claims 1 to 5.

7. Use of a modified fiber made by the method of any one of claims 1-5 in papermaking.

8. The use according to claim 7, characterized in that the modified fibres are mixed with water to form a modified fibre pulp having a concentration of 1-2wt%, and the modified fibre pulp is then made into a pulp sheet having a water content of less than 5wt% by means of a pulp sheet machine.

9. Use of a modified fiber prepared by the preparation method according to any one of claims 1 to 4 in the preparation of a lithium ion battery anode material; the method is characterized in that the modified fiber product is subjected to purification treatment, then is mixed with ammonium carbonate or melamine and is sent into a high-temperature reaction furnace, and the purified modified fiber product is prepared into the nano carbon-metal compound composite material by a vapor deposition method.