Cellulose nanocrystalline/polylactic acid composite material as well as preparation method and application thereof

A composite material and nanocrystal technology, which is applied in the field of cellulose nanocrystal/polylactic acid composite material and its preparation, can solve the problems of reduced dispersion quality, easy aggregation, and product quality decline, and achieve the effect of simple preparation method and avoiding aggregation

Active Publication Date: 2020-02-21
NORTHEAST FORESTRY UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The solvents used in this method are volatile reagents such as N,N-dimethylformamide, dichloromethane, and chloroform, which will produce a large amount of waste liquid, which is not conducive to industrial production.
When the cellulose nanocrystal / polylactic acid composite material is prepared by the melt blending method, the cellulose nanocrystal is easy to aggregate, and the sulfate ester group on the surface of the cellulose nanocrystal will be degraded under high temperature conditions. will lead to a reduction in the quality of the dispersion and ultimately a reduction in the quality of the product

Method used

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  • Cellulose nanocrystalline/polylactic acid composite material as well as preparation method and application thereof
  • Cellulose nanocrystalline/polylactic acid composite material as well as preparation method and application thereof
  • Cellulose nanocrystalline/polylactic acid composite material as well as preparation method and application thereof

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preparation example Construction

[0028] The invention provides a method for preparing a cellulose nanocrystal / polylactic acid composite material, comprising the following steps:

[0029] Mixing the aqueous dispersion of cellulose nanocrystals with a salt modifier and performing electrostatic adsorption modification to obtain a modified aqueous dispersion of cellulose nanocrystals;

[0030] The modified cellulose nanocrystal aqueous dispersion is added dropwise to the polylactic acid solution to carry out a co-precipitation reaction, and the solid obtained from the co-precipitation reaction is dried to obtain a cellulose nanocrystal / polylactic acid composite material; the poly The solvent of the lactic acid solution is a water-soluble organic solvent.

[0031] The invention mixes the cellulose nano crystal water dispersion liquid with the salt modifier, carries out electrostatic adsorption modification, and obtains the modified cellulose nano crystal water dispersion liquid. In the present invention, sulfate ...

Embodiment 1

[0052] (1) Preparation of cellulose nanocrystal aqueous dispersion:

[0053] Disperse 5g of absorbent cotton in 100mL of sulfuric acid with a concentration of 64wt%, hydrolyze at 45°C for 2h, then add 5 times the volume of the reaction liquid at 20°C to terminate the reaction; subsequently, centrifuge at 10,000rpm for 10min in a centrifuge The supernatant was removed to remove excess acid, and then the suspension was poured into a dialysis bag with a molecular weight cut off of 8000 and dialyzed against deionized water until the suspension was neutral; finally, the resulting suspension was sonicated to obtain a concentration of 0.48wt.% aqueous dispersion of cellulose nanocrystals;

[0054] (2) Electrostatic adsorption modification of cellulose nanocrystals:

[0055] Get a certain amount of said cellulose nanocrystal water dispersion, wherein the quality of cellulose nanocrystal is 0.1g, under stirring state, in the cellulose nanocrystal water dispersion, drip sodium chloride...

Embodiment 2

[0060] (1) Preparation of cellulose nanocrystal aqueous dispersion:

[0061] Disperse 5g of absorbent cotton in 100mL of sulfuric acid with a concentration of 64wt%, hydrolyze at 45°C for 2h, then add 5 times the volume of the reaction liquid at 20°C to terminate the reaction; subsequently, centrifuge at 10,000rpm for 10min in a centrifuge The supernatant was removed to remove excess acid, then the suspension was poured into a dialysis bag with a molecular weight cut off of 8000, and dialyzed with deionized water until the suspension was neutral; finally, the resulting mixture was sonicated to obtain a concentration of 0.63wt.% aqueous dispersion of cellulose nanocrystals;

[0062] (2) Electrostatic adsorption modification of cellulose nanocrystals:

[0063] Get a certain amount of the cellulose nanocrystal water dispersion, wherein the quality of the cellulose nanocrystal is 0.05g, and in a stirring state, add cetyl trimethyl bromide dropwise to the cellulose nanocrystal wat...

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Abstract

The invention provides a cellulose nanocrystalline / polylactic acid composite material as well as a preparation method and application thereof, and belongs to the technical field of polylactic acid composite materials. The preparation method comprises the following steps: mixing a cellulose nanocrystalline aqueous dispersion with a salt modifier, and carrying out electrostatic adsorption modification to obtain a modified cellulose nanocrystalline aqueous dispersion; dropwise adding the modified cellulose nanocrystalline aqueous dispersion into a polylactic acid solution, carrying out coprecipitation reaction, and drying a solid obtained by the coprecipitation reaction to obtain the cellulose nanocrystalline / polylactic acid composite material; wherein a solvent of the polylactic acid solution is a water-soluble organic solvent. According to the method, negatively charged groups on the surface of cellulose nanocrystal are effectively utilized, the modifier is adsorbed to the surface of the cellulose nanocrystal through a simple water-based method, modification is completed, the preparation process is simple, only one-time drying is needed, used water and the solvent can be recycled, and the method is a green and environment-friendly process.

Description

technical field [0001] The invention relates to the technical field of polylactic acid composite materials, in particular to a cellulose nanocrystal / polylactic acid composite material and its preparation method and application. Background technique [0002] In the past few decades, the development and application of biodegradable polymers has attracted extensive attention in academia and industry. Polylactic acid (PLA), as an ideal potential substitute for traditional petroleum-based polymers, is currently widely used in food packaging, textiles, and biomedicine. However, due to its inherent brittleness, low crystallization rate and poor barrier properties, the application of PLA in more fields is limited. [0003] Cellulose nanocrystals are nanoscale-sized cellulose crystals with high strength, excellent nucleation properties, and biodegradability, and are often used as reinforcing agents for nanocomposites. Cellulose nanocrystals / polylactic acid composites can exhibit ex...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J3/215C08J3/00C08J5/18C08L67/04C08L1/04
CPCC08J3/005C08J3/215C08J5/18C08J2367/04C08J2401/04
Inventor 张彦华李长鑫肖泽芳王成毓谢延军孙策谭海彦
Owner NORTHEAST FORESTRY UNIVERSITY
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