Strong acid pretreatment assisted cellulose nano-filament preparation method

A nanofibril and pretreatment technology, which is applied in the field of cellulose nanofibril assisted by strong acid pretreatment, can solve the problems of high energy consumption and high production cost, and achieve the effects of improving mechanical strength, increasing crystallinity, and reducing energy consumption

Active Publication Date: 2013-04-24
CENTRAL SOUTH UNIVERSITY OF FORESTRY AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to cut ordinary bleached pulp fibers into nanofibrils, repeated mechanical shearing is required during the processing, resulting in high energ

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Step 1: Swell the bleached pulp fibers in deionized water for 24 hours, then stir and disperse at high speed for 0.5 hours, and adjust to a suspended solution with a solid mass fraction of 1.5%. The mixed solution was repeatedly sheared 3 times by the ultrafine colloid mill to swell and shorten the raw material fibers; the milling disc rotation speed was 2500 rpm, and the milling disc spacing was ~0.1 mm. The pre-ground fiber solution is centrifuged to remove the upper liquid, and then centrifuged at high speed to dry to a moisture content of 12%.

[0023] Step 2: The dried fiber is hydrolyzed with concentrated sulfuric acid, the acid concentration is 64wt%, the acid hydrolysis time is 1.5h, the acid hydrolysis temperature is controlled at 50°C, and the ratio of fiber to hydrolysis acid solution is 4g / ml. The acidolysis reaction was completed in a shaker at a constant temperature (setting temperature: 50°C), and the speed of the shaker was 180 rpm.

[0024] Step 3: Rep...

Embodiment 2

[0027] Step 1: Swell the bleached pulp fibers in deionized water for 24 hours, then stir and disperse at high speed for 0.5 hours, and adjust to a suspended solution with a solid mass fraction of 2.0%. The mixed solution was repeatedly sheared 4 times by an ultrafine colloid mill to swell and shorten the raw material fibers; the milling disc rotation speed was 3000 rpm, and the milling disc spacing was ~0.1 mm. The pre-ground fiber solution is centrifuged to remove the upper liquid, and then centrifuged at high speed to dry to a moisture content of 16%.

[0028] Step 2: The dried fiber is hydrolyzed with concentrated sulfuric acid, the acid concentration is 70wt%, the acid hydrolysis time is 1.0h, the acid hydrolysis temperature is controlled at 55°C, and the ratio of fiber to hydrolysis acid solution is 6g / ml. The acidolysis reaction was completed in a constant temperature (setting temperature: 55°C) shaker with a rotation speed of 180 rpm.

[0029] Step 3: Repeatedly wash t...

Embodiment 3

[0032] Step 1: Swell the bleached pulp fibers in deionized water for 24 hours, then disperse them with high-speed stirring for 0.5 hours, and adjust them into a suspended solution with a solid mass fraction of 2%. The mixed solution was repeatedly sheared 5 times by an ultrafine colloid mill to swell and shorten the raw material fibers; the milling disc rotation speed was 3000 rpm, and the milling disc spacing was ~0.1 mm. The pre-ground fiber solution is centrifuged to remove the upper liquid, and then centrifuged at high speed to dry to a moisture content of 18%.

[0033] Step 2: The dried fiber is hydrolyzed with concentrated hydrochloric acid, the acid concentration is 70wt%, the acid hydrolysis time is 1.5h, the acid hydrolysis temperature is controlled at 50°C, and the ratio of fiber to hydrolysis acid solution is 8g / ml. The acidolysis reaction was completed in a shaker at a constant temperature (setting temperature: 50°C), and the speed of the shaker was 200 rpm.

[00...

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Abstract

A strong acid pretreatment assisted cellulose nano-filament preparation method includes: performing hydrolysis pretreatment for bleached paper pulp fibers for 1.0-1.5 hours at the temperature of 40-60 DEG C by the aid of 60-70wt% of concentrated sulfuric acid or hydrochloric acid, swelling up, dissolving and opening partial cellulose amorphous regions, and performing high-speed homogenizing mechanical shearing so that cellulose nano-filaments are obtained rapidly. The cellulose nano-filaments obtained by the method are low in energy consumption during production, high in fiber crystallization degree, large in filament length-diameter ratio and good in heat stability, and can be widely applied to the fields of reinforced composites, dust absorption filtering materials, ecological environment-friendly materials, biomedical materials and the like.

Description

technical field [0001] The invention relates to a method for preparing a plant fiber nanofibril material, in particular to a method for assisting the preparation of cellulose nanofibril by strong acid pretreatment. Background technique [0002] In recent years, plant-based nanofibers are quietly promoting the rapid development of polymer composite materials, packaging and decoration materials, energy-saving and environmental protection materials, biopharmaceutical materials, and conductive conductive materials. Cellulose nanofibrils, as an important class of nanofiber materials, often use high-speed mechanical shearing or chemical oxidation methods to separate and disassemble cellulose microfibrils in plant fibers into nanoscale (less than 100nm) diameters. elongated fibers. This nanofiber has excellent mechanical properties, with an elastic modulus as high as 100GPa; it also has a high aspect ratio, and its aspect ratio usually exceeds 100. As far as the nanostructure is ...

Claims

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Application Information

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IPC IPC(8): D21B1/02
Inventor 卿彦吴义强
Owner CENTRAL SOUTH UNIVERSITY OF FORESTRY AND TECHNOLOGY
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