Biodegradable alkali lignin composite material, preparation method and application thereof
阅读说明：本技术 一种可生物降解的碱木质素复合材料、制备方法及其应用 (Biodegradable alkali lignin composite material, preparation method and application thereof ) 是由 谢勤 余立宁 祝金侠 于 2021-08-06 设计创作，主要内容包括：本发明公开了一种可生物降解的碱木质素复合材料,包括以下重量配比的原料：碱木质素10-60份、聚谷氨酸20-80份、蒙脱土10-30份、硅烷偶联剂20-40份、甘油30-200份和溶剂200-400份。本发明还公开了所述可生物降解的碱木质素复合材料的制备方法及其在薄膜、片材或板材上的应用。本发明所述可生物降解的碱木质素复合材料能够充分利用造纸副产品碱木质素的可生物降解的碱木质素复合材料,同时也改善率原材料聚谷氨酸的性能,使得碱木质素复合材料具有较好的阻隔性能和拉伸强度,以及低的吸水率,从而扩大了碱木质素复合材料的应用范围。(The invention discloses a biodegradable alkali lignin composite material, which comprises the following raw materials in parts by weight: 10-60 parts of alkali lignin, 20-80 parts of polyglutamic acid, 10-30 parts of montmorillonite, 20-40 parts of silane coupling agent, 30-200 parts of glycerol and 400 parts of solvent 200-. The invention also discloses a preparation method of the biodegradable alkali lignin composite material and application of the biodegradable alkali lignin composite material in films, sheets or plates. The biodegradable alkali lignin composite material can fully utilize the biodegradable alkali lignin composite material of papermaking byproduct alkali lignin, and simultaneously improve the performance of the raw material polyglutamic acid, so that the alkali lignin composite material has better barrier property and tensile strength and low water absorption, thereby expanding the application range of the alkali lignin composite material.)
1. A biodegradable alkali lignin composite material, characterized in that: the method comprises the following raw materials: alkali lignin, polyglutamic acid, montmorillonite and silane coupling agent.
2. A biodegradable alkali lignin composite material according to claim 1, characterized in that: the raw material also comprises glycerol.
3. The method of claim 2, wherein the alkali lignin composite is biodegradable and the alkali lignin composite is prepared by the following steps: the raw materials also comprise dimethyl sulfoxide or N-methyl-2-pyrrolidone serving as a solvent.
4. The method of claim 1, wherein the alkali lignin composite is biodegradable and comprises: the silane coupling agent is one of alkyl triethoxy, methyl trimethoxy, triacetoxy and propyl triacetoxy silane.
5. A biodegradable alkali lignin composite material according to claim 3, characterized in that: the raw materials comprise, by weight, 10-60 parts of alkali lignin, 20-80 parts of polyglutamic acid, 10-30 parts of montmorillonite, 20-40 parts of a silane coupling agent, 30-200 parts of glycerol and 400 parts of a solvent 200-.
6. A biodegradable alkali lignin composite material according to claim 5, characterized in that: the raw materials comprise, by weight, 30 parts of alkali lignin, 50 parts of polyglutamic acid, 20 parts of montmorillonite, 30 parts of a silane coupling agent, 100 parts of glycerol and 150 parts of a solvent.
7. A method of preparing a biodegradable alkali lignin composite material according to any one of claims 1 to 6, wherein: the method comprises the following steps:
(1) adding alkali lignin powder into glycerol, and stirring to obtain alkali lignin suspension;
(2) dissolving polyglutamic acid in a solvent, and stirring to prepare a polyglutamic acid solution;
(3) and (3) adding montmorillonite into the polyglutamic acid solution obtained in the step (2) for mixing, adding the alkali lignin suspension and the silane coupling agent, and blending to prepare the alkali lignin composite material.
8. The method of claim 7, wherein the alkali lignin composite is biodegradable and comprises: the blending time is 12-48h, and the blending temperature is 70-85 ℃.
9. Use of an alkali lignin composite according to any one of claims 1 to 6 or 8, wherein: the alkali lignin composite material is applied to films, sheets or plates.
10. Use of a biodegradable alkali lignin composite material according to claim 9, characterized in that: the alkali lignin composite material is prepared into a film, a sheet or a plate by a film blowing method, a tape casting method, a solution pouring method, a spin coating method, a calendaring method, a multilayer co-extrusion method, a biaxial stretching method or a laminating method.
Technical Field
The invention relates to the field of high polymer materials, in particular to a biodegradable alkali lignin composite material, a preparation method and application thereof.
Background
With the rapid development of economic society, the wide use of high polymer materials, especially plastic films, sheets and plates, brings great convenience to the life of people, most of plastic products are extracted from petroleum, the plastic products are difficult to degrade, the degradation time is hundreds of years, and the environment is polluted to a great extent, which is known as 'white pollution'. After a new edition ' plastic forbidden ' policy ' in 1 month in 2020 comes out, the policy ' plastic forbidden ' in each place obviously accelerates. According to the content of the central and local policies, the plastic-forbidden policy is about to be spread across the whole country within 2-5 years in the future. However, most enterprises focus on material synthesis, and domestic efforts on the research of improving the performance of degradable plastic products are weak.
The lignin is a renewable and degradable natural polymer substance, and has the advantages of high impact strength, good heat resistance, water resistance, low price, easy obtainment and the like. The lignin and the derivative thereof contain a large amount of oxygen-containing active functional groups, but due to pi-pi action between aromatic rings and hydrogen bond action between carboxyl, hydroxyl and various ether bonds in the structure, the lignin is seriously aggregated, a hydrophobic chain easily wraps the active functional groups to form aggregates, and the specific surface area is small; the pyrolysis temperature is between 100 and 180 ℃, and the heat resistance is good. As a by-product of the pulp and paper industry, a large amount of alkali lignin produced annually is to be utilized. The AL is obtained by chemical pulping by a caustic soda method or a sulfate method, is hydrophobic but is soluble in an alkaline medium, and has lower sulfur content and higher reaction activity. The lignin and the derivatives thereof are blended with other materials to prepare the composite material with excellent performance, and simultaneously, the pollution of the papermaking waste liquid to the environment can be reduced. Chirico and the like blend lignin and polypropylene (PP), and compared with a blending system added with melamine, ammonium dihydrogen phosphate and other flame retardants, the addition of lignin is proved to improve the thermal stability of PP and reduce the heat release rate.
Polyglutamic acid (gamma-PGA) is a biodegradable amino acid polymer, and the synthesis method of the gamma-PGA mainly comprises a chemical synthesis method, an extraction method and a microbial fermentation method, wherein the gamma-PGA is prepared by microbial fermentation, and the method has the characteristics of easily available raw materials, recycling and regeneration, accordance with sustainable development, and has good economic value and application prospect. At present, gamma-polyglutamic acid has been found to be a polyamino acid useful as a packaging material. Gamma-PGA has the advantages of good film forming property, plasticity, cohesiveness, biodegradability and the like, and is a high molecular compound which is harmless to human bodies and environment. However, γ -PGA has a strong water absorption property, and when it is used for food packaging materials, the barrier property of γ -PGA is not satisfactory.
Therefore, in order to fully utilize the byproducts of the paper industry and improve the performance of γ -PGA in food packaging, processing, functional materials, etc., studies on blending of alkali lignin and polyglutamic acid have been made.
Disclosure of Invention
Therefore, the invention aims to provide a biodegradable alkali lignin composite material which can fully utilize the paper making byproduct alkali lignin, and simultaneously improve the performance of the raw material polyglutamic acid, so that the alkali lignin composite material has better barrier property and tensile strength and low water absorption rate, thereby expanding the application range of the alkali lignin composite material.
The technical scheme of the invention is realized as follows:
a biodegradable alkali lignin composite material comprises the following raw materials: alkali lignin, polyglutamic acid, montmorillonite and silane coupling agent.
The further technical proposal is that the raw material also comprises glycerol.
The further technical proposal is that the raw material also comprises dimethyl sulfoxide or N-methyl-2-pyrrolidone as a solvent.
The further technical scheme is that the raw materials comprise, by weight, 10-60 parts of alkali lignin, 20-80 parts of polyglutamic acid, 10-30 parts of montmorillonite, 20-40 parts of a silane coupling agent, 30-200 parts of glycerol and 400 parts of a solvent.
The further technical scheme is that the raw materials comprise 30 parts of alkali lignin, 50 parts of polyglutamic acid, 20 parts of montmorillonite, 30 parts of silane coupling agent, 100 parts of glycerol and 150 parts of solvent by weight.
A preparation method of the biodegradable alkali lignin composite material comprises the following steps:
(1) adding alkali lignin powder into glycerol, and stirring to obtain alkali lignin suspension;
(2) dissolving polyglutamic acid in a solvent, and stirring to prepare a polyglutamic acid solution;
(3) and (3) adding montmorillonite into the polyglutamic acid solution obtained in the step (2) for mixing, adding the alkali lignin suspension and the silane coupling agent, and blending to prepare the alkali lignin composite material.
The further technical proposal is that the blending time is 12-48h, and the blending temperature is 70-85 ℃.
The application of the alkali lignin composite material in films, sheets or plates is provided.
The alkali lignin composite material is further prepared into a film, a sheet or a plate by a film blowing method, a tape casting method, a solution pouring method, a spin coating method, a calendaring method, a multilayer co-extrusion method, a biaxial stretching method or a laminating method.
Compared with the prior art, the invention has the beneficial effects that:
(1) the blocking performance of the alkali lignin composite material is improved by adding montmorillonite, wherein the montmorillonite is 2: 1 type three-layer structure silicate, the thickness of each layer and the original distance between the layers are about 1nm, the two-dimensional size is about 100nm, the montmorillonite is filled in the alkali lignin composite material to improve the blocking capability of the alkali lignin composite material to water vapor, and the mechanism of the blocking sheet is similar to that of a blocking sheet formed by blocking resin in layered blending; in addition, the addition of the alkali lignin further improves the barrier property of the alkali lignin composite material.
(2) The silane coupling agent improves the bonding strength of the alkali lignin and the polyglutamic acid, promotes the compatibility of the alkali lignin and the polyglutamic acid, and finally improves the tensile strength of the alkali lignin composite material.
(3) The water absorption performance of the original polyglutamic acid is reduced by combining the alkali lignin and the polyglutamic acid, and the water absorption rate is about 15%.
(4) The glycerol is used as a solvent of the alkali lignin, so that the alkali lignin is dissolved in the solvent, and the compatibility and permeability of the alkali lignin and the polyglutamic acid are enhanced.
(5) The alkali lignin composite material disclosed by the application selects biodegradable alkali lignin and polyglutamic acid as main raw materials, but due to the fact that the biodegradation rate of the polyglutamic acid is too high, the biodegradation rate of the alkali lignin composite material is slowed down by adding the alkali lignin, and the application range of the alkali lignin composite material is expanded; meanwhile, the alkali lignin composite material has the characteristics of easily obtained raw materials, cyclic regeneration and accordance with sustainable development.
Detailed Description
For clear and complete description of the technical solutions in the present invention, it is obvious that the inventor combines the embodiments to describe, but the following embodiments describe only some embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
A biodegradable alkali lignin composite material comprises the following raw materials in parts by weight: 30 parts of alkali lignin, 50 parts of polyglutamic acid, 20 parts of montmorillonite, 30 parts of silane coupling agent, 100 parts of glycerol and 150 parts of dimethyl sulfoxide.
A preparation method of the biodegradable alkali lignin composite material comprises the following steps:
(1) adding alkali lignin powder into glycerol, and stirring to obtain alkali lignin suspension;
(2) dissolving polyglutamic acid in a solvent, and stirring to prepare a polyglutamic acid solution;
(3) and (3) adding montmorillonite into the polyglutamic acid solution obtained in the step (2) for mixing, adding the alkali lignin suspension and the silane coupling agent, and blending to prepare the alkali lignin composite material. The blending time is 12h, and the blending temperature is 85 ℃.
The alkali lignin composite material is prepared into a film by a film blowing method.
Example 2
A biodegradable alkali lignin composite material comprises the following raw materials in parts by weight: 10 parts of alkali lignin, 20 parts of polyglutamic acid, 10 parts of montmorillonite, 20 parts of silane coupling agent, 30 parts of glycerol and 200 parts of N-methyl-2-pyrrolidone.
A preparation method of the biodegradable alkali lignin composite material comprises the following steps:
(1) adding alkali lignin powder into glycerol, and stirring to obtain alkali lignin suspension;
(2) dissolving polyglutamic acid in a solvent, and stirring to prepare a polyglutamic acid solution;
(3) and (3) adding montmorillonite into the polyglutamic acid solution obtained in the step (2) for mixing, adding the alkali lignin suspension and the silane coupling agent, and blending to prepare the alkali lignin composite material.
The further technical proposal is that the blending time is 48 hours, and the blending temperature is 70 ℃.
The alkali lignin composite material is made into a sheet material by a film blowing method and a rolling method.
Example 3
A biodegradable alkali lignin composite material comprises the following raw materials in parts by weight: 60 parts of alkali lignin, 80 parts of polyglutamic acid, 30 parts of montmorillonite, 40 parts of silane coupling agent, 200 parts of glycerol and 400 parts of dimethyl sulfoxide.
A preparation method of the biodegradable alkali lignin composite material comprises the following steps:
(1) adding alkali lignin powder into glycerol, and stirring to obtain alkali lignin suspension;
(2) dissolving polyglutamic acid in a solvent, and stirring to prepare a polyglutamic acid solution;
(3) and (3) adding montmorillonite into the polyglutamic acid solution obtained in the step (2) for mixing, adding the alkali lignin suspension and the silane coupling agent, and blending to prepare the alkali lignin composite material. The blending time is 24h, and the blending temperature is 80 ℃.
The alkali lignin composite material is prepared into a plate by a laminating method.
Comparative example 1
A biodegradable polyglutamic acid material comprises the following raw materials in parts by weight: 50 parts of polyglutamic acid, 20 parts of montmorillonite, 30 parts of silane coupling agent, 100 parts of glycerol and 150 parts of dimethyl sulfoxide.
A preparation method of the biodegradable polyglutamic acid material comprises the following steps: dissolving polyglutamic acid in dimethyl sulfoxide, and stirring to obtain polyglutamic acid solution; montmorillonite is added into the polyglutamic acid solution to be mixed, and then glycerin and silane coupling agent are added to be mixed to prepare the polyglutamic acid material. The blending time is 12h, and the blending temperature is 85 ℃.
The alkali lignin composite material is prepared into a film by a film blowing method.
Comparative example 2
A biodegradable polyglutamic acid material comprises the following raw materials in parts by weight: 50 parts of polyglutamic acid, 20 parts of montmorillonite and 150 parts of dimethyl sulfoxide.
Comparative example 3
A biodegradable polyglutamic acid material comprises the following raw materials in parts by weight: 50 parts of polyglutamic acid and 150 parts of dimethyl sulfoxide.
A preparation method of the biodegradable polyglutamic acid material comprises the following steps: dissolving polyglutamic acid in dimethyl sulfoxide, and stirring to obtain polyglutamic acid solution; montmorillonite is added into the polyglutamic acid solution to be mixed and blended to prepare the polyglutamic acid material. The blending time is 12h, and the blending temperature is 85 ℃.
The alkali lignin composite material is prepared into a film by a film blowing method.
Comparative example 4
The weight ratio of the raw materials of the biodegradable alkali lignin composite material is the same as that of the raw material in example 1. The preparation method of the biodegradable alkali lignin composite material comprises the following steps:
(1) adding alkali lignin powder into glycerol, and stirring to obtain alkali lignin suspension;
(2) dissolving polyglutamic acid in a solvent, and stirring to prepare a polyglutamic acid solution;
(3) and simultaneously adding montmorillonite, alkali lignin suspension and a silane coupling agent into the polyglutamic acid solution, stirring, and blending to prepare the alkali lignin composite material. The blending time is 12h, and the blending temperature is 85 ℃.
The alkali lignin composite material is prepared into a film by a film blowing method.
Performance testing
The alkali lignin composite materials described in examples 1-3 and the polyglutamic acid materials described in comparative examples 1-2 were subjected to performance tests (see table 1), tensile performance tests were performed according to B/T1040-1992, sample size 320 × 150 × 3mm, tensile speed 100 mm/min; performing water vapor transmission test according to GB/T1037-1988 at 23 deg.C and 90% humidity; the method for testing the biodegradation rate comprises the following steps: drying the film sample to constant weight and weighing m0Placing in Hainan outdoor red soil, taking out the film sample after 15 days, drying to constant weight, and weighing m1Degradation rate ═ m0-m1)/m0100 percent; water absorption was measured according to GB1034-2008, samples having a thickness of 1mm were taken by mechanical one-side machining and tested for water absorption in water at 23 ℃.
TABLE 1
As can be seen from Table 1, the tensile strength of the alkali lignin composite materials described in examples 1-3 is significantly higher than that of comparative examples 1-3, indicating that the mechanical properties of the alkali lignin composite materials are superior to those of polyglutamic acid materials. The water vapor transmission rate of the alkali lignin composite materials described in examples 1-3 is lower than that of comparative examples 1-3, which shows that the addition of alkali lignin also further improves the barrier property of the alkali lignin composite materials, and the water vapor transmission rate of comparative examples 1-2 is lower than that of comparative example 3, which shows that montmorillonite can improve the barrier property of polyglutamic acid. The water vapor transmission rate of example 1 is lower than that of comparative example 4, which shows that the method of adding montmorillonite and polyglutamic acid solution first, and then adding alkali lignin suspension and silane coupling agent is lower than that of the method of adding montmorillonite, alkali lignin suspension and silane coupling agent simultaneously into polyglutamic acid solution, and the alkali lignin composite material prepared by the method has lower water vapor transmission rate and better barrier property. The biodegradation rate and the water absorption rate of examples 1 to 3 are lower than those of comparative examples 1 to 3, which shows that the addition of alkali lignin slows down the biodegradation performance of the material and reduces the water absorption performance of the material, thereby expanding the application range of polyglutamic acid.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.