CN-121427443-B - High-light-resistance nano lignin-based composite coating and preparation method and application thereof

Abstract

The invention discloses a high-light-resistance nano lignin-based composite coating, and a preparation method and application thereof, and belongs to the technical field of wood protection. Compared with the traditional unmodified lignin, the high-light-resistance nano lignin-based composite coating prepared by taking the lignin nanoparticles prepared by quaternizing lignin and nano TiO 2 as raw materials has more excellent light resistance, and the high-light-resistance nano lignin-based composite coating provided by the invention can retain the original texture of wood and effectively make up the defects of the traditional protection method. In addition, the preparation method of the high-light-resistance nano lignin-based composite coating provided by the invention saves raw materials and has higher resource utilization rate. The strong light-resistant nano lignin-based composite coating can obviously improve the ageing resistance of wood and expand the application prospect in the fields of outdoor landscape building materials, durable furniture, wood packaging and the like.

Inventors

• LI LILI
• YU JIANFANG
• LIU WENWEN
• HE QIN
• ZHANG YUQI
• WANG XIMING
• LIU DE
• REN YIJUN
• CHEN TIANYI

Assignees

• 内蒙古农业大学

Dates

Publication Date

20260508

Application Date

20260105

Claims (6)

1. 1. The preparation method of the high-light-resistance nano lignin-based composite coating is characterized by comprising the following steps of adding a surfactant into an ethanol solution containing a silane coupling agent, adding nano titanium dioxide and lignin nano particles into the obtained mixed solution, uniformly mixing to obtain a dispersion liquid, and spraying the dispersion liquid onto a substrate to obtain the high-light-resistance nano lignin-based composite coating; The mass ratio of the lignin nano particles to the nano titanium dioxide is 1:2; Dissolving alkali lignin in a sodium hydroxide solution, dropwise adding a 3-chloro-2-hydroxypropyl trimethyl ammonium chloride solution after first stirring, heating and stirring to obtain a quaternized lignin solution, and sequentially performing first dialysis purification and first freeze drying to obtain the quaternized lignin; adding the quaternized lignin into an organic solvent, stirring at room temperature, adding concentrated nitric acid into the obtained suspension until the pH value of the solution is 5.5, and then sequentially carrying out ultrasonic treatment, secondary dialysis purification and secondary freeze drying to obtain lignin nano particles; the substrate is selected from wood materials; the surfactant is selected from sodium dodecyl sulfate, and the silane coupling agent is selected from gamma-glycidyl ether oxypropyl trimethoxy silane.
2. 2. The method for preparing the high light resistance nano lignin-based composite coating according to claim 1, wherein the nano titanium dioxide has a particle size of 30nm and the lignin nanoparticles have a particle size of 174nm.
3. 3. The method for preparing the high-light-resistance nano lignin-based composite coating according to claim 1, wherein the dosage ratio of the surfactant to the silane coupling agent to the ethanol solution is 7 mg:1.4 mg:20 mL, and the mass ratio of the surfactant to the lignin nanoparticles is 1:10.
4. 4. The method for preparing the high-light-resistance nano lignin-based composite coating according to claim 1, wherein the dosage ratio of the alkali lignin to the 3-chloro-2-hydroxypropyl trimethyl ammonium chloride solution is 4g to 3.3 mL, the mass concentration of the 3-chloro-2-hydroxypropyl trimethyl ammonium chloride solution is 60wt.%, and/or the temperature of heating and stirring is 85 ℃ and the time is 4h.
5. 5. A strong lightfast nanolignin-based composite coating prepared by the method of any one of claims 1-4.
6. 6. Use of the strong lightfast nano lignin-based composite coating according to claim 5 in the preparation of green environmental protection wood protective material.

Description

High-light-resistance nano lignin-based composite coating and preparation method and application thereof Technical Field The invention belongs to the technical field of wood protection, and particularly relates to a high-light-resistance nano lignin-based composite coating, and a preparation method and application thereof. Background The UV absorber is capable of absorbing UVA (320-400 nm) and UVB (280-320 nm) UV radiation while maintaining its structural integrity. By coating or incorporating the material on the surface of the wood, ultraviolet light can be effectively shielded and the wood can be protected from damage. Ultraviolet absorbers are classified into organic and inorganic ones. The polyester organic ultraviolet absorbent (2 HBTF) synthesized by Evans et al （Photoprotection of Wood Using Polyester-Type UV-Absorbers Derived from the Reaction of 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone with Dicarboxylic Acid Anhydrides, J. Wood Chem. Technol. 30 (2010) 186-204.） can obviously inhibit the photodegradation of wood and reduce the light transmission of 380-405nm wave band, but the organic ultraviolet absorbent is easy to migrate and decompose and reduces the long-term protection capability. Yi et al （Role of α/γ Fe2O3and ZnO nano-particles in reducing photodegradation of wood components, Wood Sci. Technol. 57 (2023) 427-446） treated the pinus radiata with Fe 2O3 and ZnO nano solutions, both of which can protect the wood surface from ultraviolet damage. Inorganic ultraviolet absorbers effectively block ultraviolet rays from penetrating through the coating and reaching the inside of wood mainly by absorbing, reflecting and scattering the ultraviolet rays, but they constitute a risk for respiratory and ocular health, limiting their applicability. Although the traditional ultraviolet absorbent can improve the light resistance of wood to a certain extent, the traditional ultraviolet absorbent has the defects of poor compatibility with wood matrix, easy migration or decomposition under long-term irradiation of ultraviolet rays and the like, and part of products have toxicity problems, so that the application requirements of green and environment-friendly are difficult to meet. The lignin is used as a natural renewable biological resource and has the characteristics of environmental friendliness, small side effect and the like. The development of the lignin-based composite material can not only effectively reduce the environmental pollution caused by lignin waste in the paper industry and relieve the waste pressure of resources, but also realize the high-value utilization of lignin and expand the application field of lignin. The lignin is used as a natural phenolic polymer, and because the molecular structure of the lignin is rich in aromatic rings and conjugated functional groups, the lignin has strong characteristic absorption peaks in the ultraviolet region of 280-380nm, has the capability of absorbing ultraviolet rays and can be used as a natural ultraviolet blocking agent, but the high-valued application of the lignin is limited by the complex macromolecular structure of the lignin, so that the effect of the lignin is often required to be enhanced through modification and compounding. The conversion of lignin into Lignin Nanoparticles (LNP) is an important strategy breaking through the current situation, and the LNP not only maintains rich ultraviolet absorbing groups, but also remarkably improves the specific surface area and the surface activity due to the nanoscale effect. Wu et al （The mechanism of self-assembly of lignin in deep eutectic solvent based on sulfamic acid and urea through molecular dynamics simulation, Int. J. Biol. Macromol. 253 (2023)） prepared aminated LNP by deep eutectic solvent modification of sulfamic acid-urea, its micro-nano level roughness structure can widen light propagation path, enhance ultraviolet absorptivity of coating and inhibit long-term ultraviolet degradation of wood, however chemical characteristics of sulfamic acid-urea deep eutectic solvent may affect life of coating under certain environmental conditions. The colloid lignin micro-nanospheres (LMNS) prepared by Song et al （Valorization of Lignin from Biorefinery: Colloidal Lignin Micro-Nanospheres as Multifunctional Bio-Based Fillers for Waterborne Wood Coating Enhancement, ACS Sustainable Chem. Eng. 10 (2022) 11655-11665） through a self-assembly process can effectively block ultraviolet rays and provide excellent protection for the color of wood, but LMNS is insufficient in self structural stability, and the ultraviolet protection efficiency of a coating can be gradually reduced after long-term use. TiO 2 has excellent ultraviolet absorption performance and is a common ultraviolet screening agent for high polymer materials. However, the TiO 2 has the problems of strong polarity and easy agglomeration, and has poor compatibility with high polymer materials, so that the performance of the TiO 2 is greatly limit