Surface hydrophobic modification method of nano cellulose

A nano-cellulose and hydrophobic modification technology, applied in the field of polymer materials, can solve the problems of lengthy solvent exchange process, complicated and lengthy steps, few steps, etc.

Inactive Publication Date: 2018-10-02
NANJING FORESTRY UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problems of complicated and lengthy steps and large consumption of organic solvents in the process of hydrophobic modification of nano-cellulose in the prior art, and to provide a method for surface hydrophobic modification of nano-cellulose, which significantly improves the performance of nano-cellulose. Stability and redispersibility, and the hydrophobic modification method has few steps, and in-situ solvent replacement directly occurs during the modification process, avoiding the lengthy solvent exchange process

Method used

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  • Surface hydrophobic modification method of nano cellulose

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Effect test

Embodiment 1

[0026] A method for surface hydrophobic modification of nanocellulose, comprising the steps of:

[0027] (1) adding nanocellulose to distilled water, mixing uniformly to obtain a nanocellulose suspension with a concentration of 2wt%;

[0028] (2) Add DL-lactic acid solution with a mass fraction of 85% in the above-mentioned CNF suspension, the weight of DL-lactic acid solution is 10 times of the weight of the CNF suspension, the ultrasonic dispersion is uniform, the ultrasonic time is 2min, and the frequency of ultrasonic dispersion is 20KHz;

[0029] (3) Put the uniformly dispersed mixed solution in a three-necked flask, add the metal oxide catalyst tin protochloride (the amount is 5 / 10,000 of the DL-lactic acid solution), and then place the three-necked flask in a constant temperature oil bath at 180°C distilled in

[0030] (4) In step (3), when 99% of the water in the CNF suspension is distilled out, add the esterification modifier alkenyl succinic acid (200ml alkenyl suc...

Embodiment 2

[0034] A method for surface hydrophobic modification of nanocellulose, comprising the steps of:

[0035] (1) adding nanocellulose to distilled water, mixing uniformly to obtain a nanocellulose suspension with a concentration of 5wt%;

[0036] (2) Add DL-lactic acid syrup solution with a mass fraction of 85% to the above CNF suspension, the weight of the DL-lactic acid solution is 10 times the weight of the CNF suspension, the ultrasonic dispersion is uniform, the ultrasonic time is 5min, and the frequency of ultrasonic dispersion is 20KHz;

[0037] (3) Put the uniformly dispersed mixed solution in a three-necked flask, add the metal oxide catalyst zinc acetate dihydrate (the amount is 5 / 10,000 of the DL-lactic acid solution), and then place the three-necked flask in a constant temperature oil bath at 160°C distilled in

[0038] (4) After 90% of the water in the CNF suspension is distilled out, the esterification modifier glutaric acid (add 250ml glutaric acid per 1g of nanoc...

Embodiment 3

[0042] A method for surface hydrophobic modification of nanocellulose, comprising the steps of:

[0043] (1) adding nanocellulose to distilled water, mixing uniformly to obtain a nanocellulose suspension with a concentration of 6wt%;

[0044] (2) Add DL-lactic acid solution with a mass fraction of 85% in the above-mentioned CNF suspension, the weight of DL-lactic acid solution is 10 times of the weight of the CNF suspension, the ultrasonic dispersion is uniform, the ultrasonic time is 8min, and the frequency of ultrasonic dispersion is 20KHz.

[0045] (3) Put the uniformly dispersed mixed solution in a three-necked flask, add metal oxide catalyst zinc acetate dihydrate (the amount is 5 / 10,000 of the DL-lactic acid syrup solution), and then place the three-necked flask in a constant temperature oil bath at 170°C distillation in a pot;

[0046] (4) After 85% of the water in the CNF suspension is distilled out, add the esterification modifier linseed oil (add 400ml linseed oil ...

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Abstract

The invention relates to a surface hydrophobic modification method of nano cellulose. The method comprises: preparing a nano cellulose suspension first, then adding a DL-lactic acid solution, and uniformly dispersing the materials to obtain a mixed solution; then adding a metal oxide catalyst, uniformly stirring the materials, and heating the mixture to 150-200 DEG C for distillation; when 50-100%of water in the mixed solution is distilled out, adding an esterification modifier and a metal oxide catalyst, stirring the materials evenly and raising the temperature to 170-220 DEG C for reaction;and after the reaction, adding the reaction product into ethanol and carrying out centrifugal separation to obtain a solid which is modified nano cellulose. The method provided by the invention solves the problems of complicated and lengthy steps, high organic solvent consumption and the like existing in a modification method in the prior art, has few steps, avoids a lengthy solvent exchange process, can recycle excessive reaction reagents after reaction, and has obvious economic and environmental protection advantages.

Description

technical field [0001] The invention relates to a surface hydrophobic modification method of nano-cellulose, which belongs to the technical field of polymer materials. Background technique [0002] Nanocellulose (Cellulose Nanofiber, CNF) is derived from natural fibers. Compared with ordinary cellulose, the aspect ratio of CNF can reach thousands, and the huge aspect ratio enables the internal stress to be effectively transmitted between CNF and the polymer matrix. . At the same time, due to the special structural characteristics and high crystallinity, the Young's modulus of CNF can reach up to 140GPa, the strength can reach up to 2-3GPa, and the thermal expansion coefficient is only 10 -7 K -1 . These properties make CNFs widely used in reinforcing composite materials. However, CNF has a large surface area, abundant hydroxyl groups on the surface, and strong polarity. The particles are easily agglomerated through hydrogen bonding, and the agglomerated CNF is difficult ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G63/08C08G63/91C08B15/02
CPCC08B15/02C08G63/08C08G63/912
Inventor 方露陈楚楚徐航天王海莹
Owner NANJING FORESTRY UNIV
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