CN111574738B

CN111574738B - Preparation method of nano cellulose-based bionic heterogeneous membrane material

Info

Publication number: CN111574738B
Application number: CN202010466957.0A
Authority: CN
Inventors: 徐环斐; 车欣鹏; 李滨
Original assignee: Qingdao University of Science and Technology
Current assignee: Qingdao University of Science and Technology
Priority date: 2020-05-28
Filing date: 2020-05-28
Publication date: 2022-08-02
Anticipated expiration: 2040-05-28
Also published as: CN111574738A

Abstract

The invention provides a preparation method of a nano cellulose based bionic heterogeneous membrane material. The method is characterized in that: the preparation method comprises the steps of taking agricultural and forestry waste biomass as a raw material, preparing nano-cellulose containing lignin by combining acid hydrolysis pretreatment with a high-pressure homogenization process, and preparing the heterogeneous membrane with the graphene oxide layer and the nano-cellulose layer tightly combined by using the lignin as an adhesive in a simple layer-by-layer suction filtration mode. And then, immersing the heterogeneous membrane in a solution for reduction treatment under a mild condition to change the graphene oxide layer into a reduced graphene oxide layer, and drying to obtain the heterogeneous membrane with high flexibility, conductivity, strong water resistance and high mechanical strength. Due to the fact that the water absorption rate and the electro-optic thermal effect of the two layers of materials are different, the bionic heterogeneous membrane material has the responsivity of humidity, near infrared radiation, electrical stimulation and the like. Can be used for manufacturing devices such as humidity sensors, bionic artificial arms, bionic driving motors and the like.

Description

Preparation method of nano cellulose based bionic heterogeneous membrane material

Technical Field

The invention belongs to the technical field of nano functional materials, and particularly relates to a preparation method of a nano cellulose based bionic heterogeneous membrane material.

Background

As a natural polymer material, nanocellulose has been applied in the fields of packaging, drug sustained release, biomimetic materials and the like. The reduced graphene oxide is a two-dimensional material with good conductivity, and has wide application prospects in the fields of nano composite materials and the like.

At present, a composite material prepared by blending nano-cellulose and reduced graphene oxide is one of research hotspots. The reduced graphene oxide has good conductivity, but the conductivity of the composite material is poor in the process of preparing the self-assembled film by blending and compounding the nano-cellulose and the reduced graphene oxide. The nanocellulose is an insulating natural polymer, and in the process of mixed membrane preparation, the nanocellulose is doped in the reduced graphene oxide nanosheets, so that the reduced graphene oxide with good conductivity is prevented from forming a compact conductive network, and the conductivity of the material is reduced. Meanwhile, if a large amount of the reduced graphene oxide with good conductivity is doped into the nanocellulose, the mechanical property and the water resistance of the composite membrane are greatly reduced. If the two materials are simply formed into films respectively and then compounded together, the whole structure is unstable, the materials are easy to delaminate and separate when meeting water, and the like, so that the durability of the materials in repeated use in a high-humidity environment is influenced; if the adhesive is additionally added, the defects of increasing the operation complexity, introducing other agents serving as adhesives, improving the material cost and the like are overcome. At present, reduction treatment of graphene oxide in a material under a mild condition after compounding nanocellulose and graphene oxide is not reported temporarily. The conventional reduction conditions such as iron reduction, sulfonation reduction, hydrazine reduction, electrochemical reduction, hydroiodic acid reduction and the like have the defects of high toxicity, harsh reaction conditions, easiness in damaging the structure of a nano cellulose layer in the composite material and the like.

Therefore, in order to solve the problems, the invention takes agricultural and forestry waste biomass resources as raw materials, has simple operation, mild reaction conditions and environmental protection, and prepares the nano cellulose-based bionic heterogeneous membrane with conductivity, high flexibility, high mechanical strength and high humidity resistance. Due to the fact that the water absorption rates of the heterogeneous membrane materials are different, the bionic heterogeneous membrane material has humidity, near-infrared radiation and electric stimulation responsiveness. Is expected to be used for manufacturing devices such as humidity sensors, bionic artificial arms, bionic driving motors and the like, and has important significance for preparing nano-cellulose and reduced graphene oxide bionic composite materials.

Disclosure of Invention

The invention aims to provide a preparation method of a nano cellulose based bionic heterogeneous membrane material.

The technical scheme adopted by the invention comprises a preparation method of a nano cellulose based bionic heterogeneous membrane material, which is characterized by comprising the following steps: the lignocellulose biomass of agricultural and forestry waste is used as a raw material, and the nano-cellulose containing the lignin is prepared by a formic acid hydrolysis method. The cellulose nano paper prepared by the formic acid method has ester groups on the surface and water resistance, and the structure of the cellulose nano paper cannot be damaged even if the cellulose nano paper is soaked in water for a long time. Meanwhile, a large amount of lignin is reserved in the process of hydrolyzing the agricultural and forestry waste by formic acid, and the lignin serves as a binder. In order to give consideration to the good conductivity of the reduced graphene oxide and the good mechanical property of the nanocellulose, the composite membrane of the graphene oxide and the nanocellulose is prepared in a layer-by-layer suction filtration mode which is simple and convenient to operate, and is subjected to reduction treatment in an ascorbic acid solution, so that the graphene oxide layer without the conductivity is reduced into the reduced graphene oxide layer with the conductivity, and the electrical characteristics are obtained.

The cellulose-based nanocomposite prepared by the method has obvious response effects on near-infrared light stimulation, electrical stimulation and humidity stimulation. Meanwhile, different near infrared light energy density stimuli and different current magnitude electrical stimuli and the like are found to have different influences on the driving performance of the heterogeneous membrane material. The heterogeneous membrane composite material can be used for preparing a bionic intelligent gripper, flexible gripping is realized, and devices such as bionic squids are prepared by utilizing the electro-optic-thermal conversion effect of reduced graphene oxide. The heterogeneous membrane prepared by the method has good stability in water, is not easy to delaminate, and has good application prospect in a high-humidity environment. The invention provides a new strategy for preparing a flexible bionic heterogeneous membrane by utilizing lignocellulose biomass of agricultural and forestry waste, and has good economic and environmental benefits.

The invention has the advantages that:

1. the lignocellulose biomass in the agricultural and forestry waste is fully utilized, the raw material source is rich, the cost is low, and the high value-added utilization of the agricultural and forestry waste is realized.

2. The two layers of the heterogeneous membrane are respectively a nano cellulose layer and a reduced graphene oxide layer, in order to ensure the close adhesion between the two layers and prevent the layering and delamination phenomena in use, no additional adhesive is needed to be added, and lignin reserved in the process of preparing nano cellulose by adopting a formic acid method is used as the adhesive of the nano cellulose layer and the reduced graphene oxide layer. And the introduction of other chemical reagents in the preparation of the material is reduced.

3. The heterogeneous membrane material which is formed is soaked in ascorbic acid solution under mild conditions to reduce the graphene oxide layer, so that the heterogeneous membrane material obtains good conductivity. Avoids toxic, complex and high-cost reduction conditions, and is simply treated by a soaking mode. The process is simple to operate and environment-friendly.

4. The heterogeneous film prepared has good flexibility, water resistance and good mechanical strength. The bionic heterogeneous membrane material has humidity, near infrared radiation and electrical stimulation responsiveness.

Drawings

FIG. 1 is a flow chart of the preparation of a bionic heterogeneous membrane material

FIG. 2 shows the process of grasping an object under the drive of near infrared light by using a heterogeneous membrane material as a bionic gripper

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The present invention will be further described with reference to specific examples, but the present invention is not limited thereto.

Example 1

Takes tobacco stalks as raw materials, directly extracts the nano-cellulose containing lignin from the tobacco stalks which are not subjected to any chemical treatment through one-step formic acid treatment and subsequent homogenization treatment. The average width of the nano-cellulose is 10.5nm, and the nano-cellulose is uniform in size. And then, adopting a vacuum filtration device to carry out suction filtration on the nano cellulose dispersion liquid and drying, thereby successfully preparing the nano cellulose membrane containing the lignin. Then, a heterogeneous membrane in which nanocellulose and graphene oxide are composited was fabricated by simple two-step filtration. The graphene oxide suspension (0.2%) was vacuum filtered on top of the nanocellulose membrane to form a dense graphene oxide membrane layer on the nanocellulose membrane. After drying the heterogeneous membrane, the membrane was immersed in an ascorbic acid solution (60g/L) at 65 ℃ for 7 hours in an immersion reagent to reduce the graphene oxide layer to a reduced graphene oxide layer. And then drying the reduced wet film. And after the reduction and drying are completed, obtaining the heterogeneous membrane material of the nanocellulose and the reduced graphene oxide with the conductive function. The tensile stress of the material is 141.2 MPa; the material has good flexibility, can be folded into a small boat and the like without being broken; the resistance change is not obvious after repeated bending for 1000 times; the stability is still good after the composite material is placed in water for 100 days, and the delamination can not occur; can be used as a multi-response bionic motor and a bionic hand grip.

Example 2

The method is characterized in that straws are used as raw materials, formic acid treatment and homogenization treatment are carried out through a one-step method, and the nano-cellulose containing lignin is directly extracted from the straws which are not subjected to any chemical treatment. The average width of the nano-cellulose is 12.0nm, and the nano-cellulose is uniform in size. And then, adopting a vacuum filtration device to carry out suction filtration on the nano cellulose dispersion liquid and drying, thereby successfully preparing the nano cellulose membrane containing the lignin. Then, a heterogeneous membrane in which nanocellulose and graphene oxide are composited was fabricated by simple two-step filtration. The graphene oxide suspension (0.5%) was vacuum filtered on top of the nanocellulose membrane to form a dense graphene oxide membrane layer on the nanocellulose membrane. After drying the heterogeneous membrane, the membrane was immersed in an ascorbic acid solution (45g/L) at 60 ℃ for 8 hours to reduce the graphene oxide layer to a reduced graphene oxide layer. And then drying the reduced wet film. And after the reduction and drying are completed, obtaining the heterogeneous membrane material of the nanocellulose and the reduced graphene oxide with the conductive function. The tensile stress of the material is 155.2 MPa; the material has good flexibility, can be folded into a small boat and the like without being broken; the stability is still good after being placed in water for 100 days, and the delamination can not occur; the resistance change is not obvious after repeated bending for 1000 times; can be used as a multi-response bionic motor and a bionic hand grip.

The above description is only exemplary of the preferred embodiments of the present invention, and is not intended to limit the present invention, and any modifications, equivalents, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

It should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and the present invention is not limited thereto, and although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications and equivalents can be made in the technical solutions described in the foregoing embodiments, or equivalents thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive changes in the technical solutions of the present invention.

Claims

1. A preparation method of a nano cellulose based bionic heterogeneous membrane material is characterized by comprising the following steps: by taking lignocellulose biomass as a raw material, performing formic acid treatment and subsequent homogenization treatment by a one-step method, and directly extracting lignocellulose containing lignin from the biomass raw material which is not subjected to any chemical treatment in the early stage; then, adopting a vacuum filtration device to carry out filtration and drying on the nano cellulose dispersion liquid so as to successfully prepare the nano cellulose membrane containing the lignin; then, preparing a heterogeneous membrane compounded by nano-cellulose and graphene oxide through a simple operation mode; vacuum filtering the graphene oxide suspension on the nano cellulose membrane to form a compact graphene oxide membrane layer on the nano cellulose membrane;

drying the heterogeneous membrane, soaking the membrane in 45g/L ascorbic acid solution at 60 ℃ for 8h, or soaking the membrane in 60g/L ascorbic acid solution at 65 ℃ for 7h to change the graphene oxide layer into a reduced graphene oxide layer; drying the reduced wet film; obtaining a heterogeneous membrane material of nano-cellulose with a conductive function and reduced graphene oxide; the material has high mechanical strength and good flexibility, and can be used as a multi-response bionic motor and a bionic hand grip.

2. The method of claim 1, wherein the lignocellulosic biomass is agricultural or forestry waste.