CN112442924A

CN112442924A - Method for preparing high-hardness environment-friendly material by using protogenic plant biomass as raw material

Info

Publication number: CN112442924A
Application number: CN201910826897.6A
Authority: CN
Inventors: 张宗超; 邹春燕
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2019-09-03
Filing date: 2019-09-03
Publication date: 2021-03-05
Anticipated expiration: 2039-09-03
Also published as: CN112442924B

Abstract

The invention discloses a method for preparing a high-density hard biomass material by directly treating a primary plant biomass by using an alkaline ionic liquid. Cleaning and drying the plant biomass, and crushing the plant biomass to 20-80 meshes. Adding 5-30 parts by mass of ionic liquid into the obtained crushed particles, heating to 50-120 ℃, and treating for about 10-70 hours. And washing with an organic solvent and water to obtain viscous slurry. Pouring the slurry into a mold, and drying at 25-100 deg.C to obtain a compact and hard material with density of 1.6g/cm³The bending strength reaches 27.1 MPa. The raw material is native plant biomass, which is treated by preferred alkaline ionic liquid without additional chemical pretreatment, and the raw material is dried and polymerized after washing to remove residual ionic liquid: the pressure range in drying is 0-10MPa, and can be adjusted according to the pretreatment conditionNo pressure is applied; the drying temperature is less than 100 ℃, the energy is saved, the emission is reduced, and the process is simple. The preparation does not need to add filler, binder, auxiliary materials and the like, is nontoxic and harmless, is natural and degradable, and is a real environment-friendly material.

Description

Method for preparing high-hardness environment-friendly material by using protogenic plant biomass as raw material

Technical Field

The invention relates to a method for preparing a natural degradable full biomass material by using native biomass without other chemical pretreatment. The method does not add filler, binder, auxiliary agent and other additional substances, and external pressure can not be applied in the preparation process.

Background

The use of the artificial biological board is beneficial to relieving the dependence on wood resources, at present, the market development of the artificial board in China is fast, and various types of artificial boards are produced at the same time. Patent application No. CN201711121319 proposes that 20-80% of thermoplastic plastics (polyethylene, polypropylene, polyvinyl chloride and the like), 10-30% of other auxiliary materials (ethylene propylene diene monomer, polyolefin thermoplastic elastomer, styrene-butadiene thermoplastic elastomer and the like) and 0.5-20% of auxiliary agents (maleic anhydride graft, stearic acid, silane coupling agent, azodicarbonamide and the like) are added into 5-50% of biomass raw materials. Mixing the components, and processing and dicing the mixture by a double-screw granulator to obtain biomass plastic master batches; and then processed by a profile extruder or a sheet machine to prepare the biomass board and the sheet. CN201510413300.7 proposes a novel biomass green wood substitute sheet material, which is prepared by using natural cellulose as a main body, adding a solubilizer (one or two of maleic anhydride modified vinyl resin, ethylene-vinyl acetate copolymer and rosin modified resin), a composite auxiliary agent (one or two of natural electrically-rich mineral powder, a toughening agent and a lubricating release agent, namely zinc stearate, calcium stearate and polyethylene wax) and the like, so as to combine polymer resin and cellulose. All raw materials are required to be mixed by a high-speed mixer, then raw material ions for an extruder are formed by a high-temperature granulator, and finally the raw material ions are added into a double-screw extruder to extrude plates. CN201610995047.5 adopts chlorosulfonated polyethylene rubber and straw biomass to prepare a composite board, adds a modifier, a dispersant and an adhesive, and carries out banburying, hot-refining and hot-pressing in multiple steps to obtain the composite chlorosulfonated polyethylene rubber/biomass composite board. The performance of the board is changed by adding macromolecular resin, modifier and the like. The invention directly adopts plant biomass, namely the primary biomass without any chemical pretreatment as the raw material, and aims at the biomass raw material, screening the optimal alkaline ionic liquid, the treatment time, the treatment temperature and the self-condensation condition to prepare the high-density high-hardness material by a one-step method. The alkaline ionic liquid treatment enables the biomass to generate conditions suitable for shrinkage polymerization, other binders, auxiliaries and the like are not needed to be added in the preparation, the process is simple, and the cost is low. The material can be completely degraded, and does not bring harm to the environment and human beings.

Disclosure of Invention

The invention aims to provide a simple method for preparing a natural, environment-friendly, easily-degradable, high-density and high-strength biomass board. The recyclable alkaline ionic liquid is used for directly treating the primary plant biomass, and the high-density high-hardness environment-friendly material is prepared by a one-step method.

The method adopts the technical steps that plant biomass is polymerized into a high-density and high-hardness biomass plate after being cleaned, dried, crushed, dried again, pretreated by alkaline ionic liquid, washed by organic solvent-water and filtered and separated. Wherein:

(1) crushing: the washed and dried biomass material is crushed to 20-80 mesh, preferably 30-50 mesh particles and dried to a moisture content of less than 5%.

(2) And (3) ionic liquid treatment: adding 5-30 times of ionic liquid into the biomass powder, heating to 50-120 ℃, and treating for 10-70 hours.

(3) Washing: and washing the biomass treated by the ionic liquid with an organic solvent-water.

(4) Polymerization: the washed viscous paste is poured into a mould, dried and polymerized, and no additional pressure (0-10MPa) is applied in the process according to the pretreatment condition.

The density of the compact and hard material can reach 1.6g/cm³The bending strength reaches 27.1 MPa. The raw materials are primary plant biomass, especially crop wastes, are cheap and easy to obtain, are rich in variety, reduce pollution and fully utilize biological energy. The method has the advantages that additional chemical pretreatment is not needed, the condition suitable for shrinkage polymerization can be generated under the action of the preferred alkaline ionic liquid, no pressure is applied in the polymerization process, the drying temperature is less than 100 ℃, energy is saved, emission is reduced, and the process is simple. The preparation does not need to add filler, binder, auxiliary materials and the like, is nontoxic and harmless, is natural and degradable, and is a real environment-friendly material.

Drawings

Fig. 1 is a Scanning Electron Microscope (SEM) photograph of the prepared biomass panel.

(a) Is a cross-sectional SEM photograph of the material, and (b) is a longitudinal SEM photograph of the material.

FIG. 2 is a process flow diagram of the present invention.

Detailed Description

The present invention is further illustrated by the following specific examples, which are not intended to limit the invention.

Example 1

Cleaning corn stalk, oven drying, pulverizing, sieving to obtain 40 mesh granules, oven drying until water content is less than 5%, and adding dried material 20 times by mass ([ EMIM ]][OAc]Heating the liquid to 80 deg.C, treating under stirring for 35 hr to obtain pre-treated liquid, cooling to room temperature, adding equal volume of methanol into the pre-treated liquid, diluting, filtering, adding water, washing, filtering to obtain clear filtrate, pouring into a mold, and drying at 60 deg.C for 12 hr to obtain high density material with density of 1.6g/cm³And the compressive strength is 27.1 MPa. The scanning electron micrograph thereof is shown in FIG. 1.

Example 2

Cleaning and drying rice straws, crushing, screening out 20-mesh particles, drying until the water content is less than 5%, adding [ Bmim ] Cl ionic liquid with the mass 15 times that of the dried materials, heating to 90 ℃, treating for 25h under stirring, cooling to room temperature, filtering, adding water, washing and filtering until the filtrate is clear, pouring the residues into a mold, and drying for about 10h at 80 ℃ to obtain slag-shaped non-polymer solid.

Example 3

Cleaning and drying mixture of sorghum straw and soybean straw (mass ratio 1: 1), pulverizing, sieving to obtain particles smaller than 20 meshes, drying until water content is less than 5%, and adding dried material 20 times of weight of pyrr][OOCH]Heating ionic liquid to 90 deg.C, treating under stirring for 30h to obtain pretreatment solution, cooling to room temperature, adding equal volume of ethanol into the pretreatment solution for dilution, filtering, adding water for washing, filtering to obtain clear filtrate, pouring into a mold, applying 0.5MPa pressure, drying at 90 deg.C for 6h to obtain high density material with density of 1.5g/cm³And the compressive strength is 21.4 MPa.

Example 4

Corn straw and wheat straw (mass ratio 2:1) cleaning the mixture, oven drying, pulverizing, sieving to obtain particles smaller than 20 meshes, oven drying until the water content is less than 5%, and adding [ Ch 30 times the weight of the oven-dried material][DHP]Heating to 90 deg.C, treating under stirring for 40 hr to obtain pretreatment solution, cooling to room temperature, adding equal volume of acetone to dilute, filtering, adding water to wash, filtering to obtain clear filtrate, pouring into a mold, applying 2MPa pressure, drying at 100 deg.C for 6 hr with density of 1.2g/cm³And the compressive strength is 17.3 MPa.

Claims

1. A process for preparing high-density hard biomass material features that the dried raw plant biomass is used as raw material, which is treated through pulverizing, treating with alkaline ionic liquid, sequentially washing with organic solvent and water, filtering and drying the filter dregs at 100 deg.C or lower.

2. The method according to claim 1, comprising the specific steps of:

(1) cleaning and drying the plant biomass material, crushing, and further drying until the moisture content is less than 5 percent to obtain biomass raw material powder;

(2) adding 5-30 times of alkaline ionic liquid into biomass powder, uniformly stirring and heating, and completely swelling the material after the reaction to obtain a pretreatment solution;

(3) cooling the pretreatment solution to the room temperature of 40 ℃, adding an organic solvent for dilution and washing, then washing with water, and filtering until the filtrate is clear to obtain viscous slurry;

(4) polymerization: and pouring the washed viscous slurry into a mold, drying and polymerizing to obtain the high-density hard biomass material.

3. A method according to claim 1 or 2, characterized by: the primary plant biomass comprises one or more of dried woody plant, removed bark rhizome, whole herb, or a combination thereof; the preferable biomass includes one or more than two of crops such as corn straw, wheat straw, soybean straw, rice straw, sorghum straw, peanut straw, tobacco stalk and the like, and the processing range is not limited to the listed plant raw materials;

the plant biomass is native plant biomass without other chemical pretreatment.

4. A method according to claim 1, 2 or 3, characterized by: cleaning the pretreated plant biomass raw material, crushing the plant biomass raw material into 20-80 meshes, preferably 30-50 meshes, crushing the particles, and drying the particles until the moisture content is less than 5%.

5. A method as claimed in claim 1 or 2, characterized by: the basic ionic liquid includes but is not limited to one or more of basic reagents such as triethylamine, pyridine, pyrrolidine, imidazole, choline, quaternary ammonium salt, morpholine and the like, and one or more of ionic liquids composed of one or more of formic acid, acetic acid, phosphoric acid, potassium hydroxide and the like.

6. The method of claim 1, 2 or 5, wherein: in the ionic liquid treatment process, the mass ratio of the ionic liquid to the biomass is 5-30, preferably 10-25; the treatment temperature is 50-120 ℃, and preferably 60-100 ℃; the treatment time is 6 to 70 hours, preferably 8 to 57 hours.

7. A method according to claim 1 or 2, characterized by: the organic solvent for washing includes, but is not limited to, one or more of methanol, ethanol, acetone, and tetrahydrofuran, and is used in an amount of 0.5 to 5 times, preferably 1 to 3 times, the volume of the pretreatment solution.

8. A method according to claim 1 or 2, characterized by: the native plant biomass requires no additional chemical pretreatment, only the preferred alkaline ionic liquid treatment.

9. A method according to claim 1 or 2, characterized by: dry polymerization, which can be carried out without additional pressure; the density of the high-density hard biomass material can reach 1.6g/cm3, and the bending strength can reach 27.1 MPa.

10. The method according to claim 1 or 2 or 9, characterized by: the polymerization process is carried out under the pressure of 0-10MPa, preferably 0-5MPa according to the pretreatment condition; the pressing time is 0 to 24 hours, preferably 0 to 6 hours.

11. A method according to claim 1 or 2, characterized by: drying conditions for the condensation or polymerization process, preferably at a drying temperature of 25-100 deg.C, preferably 60-90 deg.C; the drying time is 4 to 36 hours, preferably 6 to 24 hours.