Preparation method of pH response color-changing cellulose fiber

A cellulose fiber and solution technology, which is applied in the direction of synthetic cellulose fiber, fiber treatment, plant fiber, etc., can solve the problems of large error, poor reversibility of cellulose film, and inconspicuous discoloration, etc., and achieves sensitive and reversible pH response, excellent pH-responsive color-changing properties and broad application prospects

Active Publication Date: 2018-03-13
NORTHEAST FORESTRY UNIVERSITY
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  • Abstract
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Problems solved by technology

[0004] The present invention aims to solve the problem that when the existing bromothymol blue is used as an indicator, the error is large, the color change is not obvious when the pH is between 6 and 7, the color is uneven when it is loaded on cellulose fibers, the color fades when the pH changes color, and it cannot be reused. Technical problem, the technical problem of the poor reversibility of the cellulose film embedded with the indicator, and a preparation method of the pH-responsive color-changing cellulose fiber is provided

Method used

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  • Preparation method of pH response color-changing cellulose fiber
  • Preparation method of pH response color-changing cellulose fiber

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Embodiment 1

[0031] Embodiment 1: the preparation method of the pH-responsive discoloration cellulose fiber of the present embodiment is carried out according to the following steps:

[0032] 1. Pulverize the sulfate bleached softwood pulp and pass through a 100-mesh sieve to obtain bleached softwood pulp cellulose fiber (NBKP) powder;

[0033] 2. Add 250 milliliters of NaOH solution with a mass concentration of 20% to 10 grams of bleached coniferous pulp cellulose fibers, and stir at room temperature for 2 hours at a speed of 500 r / min, and carry out solid-liquid separation through suction filtration to obtain etherified Cellulose fibers;

[0034] 3. Add 250 ml of NaOH solution with a mass concentration of 10% and 80 grams of epichlorohydrin to the etherified cellulose fiber obtained in step 2, and stir the reaction at 65° C. at a speed of 500 r / min 6h, then carry out solid-liquid separation by suction filtration, and wash away unreacted epichlorohydrin with ethanol, then add 150 ml of e...

Embodiment 2

[0048] Embodiment 2: the preparation method of the pH response variable color cellulose fiber of the present embodiment is carried out according to the following steps:

[0049] 1. Pulverize the sulfate bleached softwood pulp and pass through an 80-mesh sieve to obtain bleached softwood pulp cellulose fiber (NBKP) powder;

[0050] 2. Add 250 milliliters of NaOH solution with a mass concentration of 25% to 10 grams of bleached coniferous pulp cellulose fibers, and stir at room temperature for 3 hours at a speed of 700 r / min, and carry out solid-liquid separation through suction filtration to obtain etherified Cellulose fibers;

[0051] 3. Add 250 ml of NaOH solution with a mass concentration of 15% and 80 grams of epichlorohydrin to the etherified cellulose fiber obtained in step 2, and stir the reaction at 70°C at a speed of 700r / min 8h, then carry out solid-liquid separation by suction filtration, and wash away unreacted epichlorohydrin with ethanol, then add 150 ml of ethan...

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Abstract

The invention provides a preparation method of pH response color-changing cellulose fiber and relates to a preparation method of a pH indicator. The technical problems that when the existing bromothymol blue serves as an indicator, the error is big, the color does not change obviously when the pH is between 6 and 7, the color is non-uniform when the indicator is loaded on the cellulose fiber, andthe pH paper fades when the color changes and cannot be reused are solved. The technical problem that the cellulosefilm wrapping the indicator has low reversibility is solved. The method comprises thefollowing steps: pulverizing bleached softwood pulp, performing etherification, and performing reaction on the bleached softwood pulp, epoxy chloropropane and triethylamine sequentially to obtain quaternized bleached softwood pulp cellulose fiber; and adding a dilute alkali solution of bromothymol blue into the quaternized cellulose fiber and performing reaction to obtain the pH response color-changing cellulose fiber. The pH value response interval of the color-changing cellulose fiber is 4 to 8, the pH response is sensitive and reversible, color does not fade, and the pH response color-changing cellulose fiber can be made into test paper, packaging paper and the like.

Description

technical field [0001] The invention relates to a preparation method of a pH indicator, belonging to the technical field of material processing. Background technique [0002] Discoloration refers to the color change of a substance after a physical or chemical reaction. The material made of the discoloration of the material becomes the discoloration material. According to the way the material is subjected to external stimuli, there are mainly photochromic, heat-induced discoloration, electrochromic and acid-induced discoloration. Bromothymol blue, also known as bromothymol blue, molecular formula C 27 h 28 o 5 SBr 2 , is an acid-base indicator, adsorption indicator, the color of bromothymol blue dilute alkali solution will change with the pH, often used in the titration process, but the color change of the liquid is a process, when observed with the eyes Usually there is the problem of larger titration errors, and bromothymol blue does not change color when the pH is be...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D06M11/38D06M13/11D06M13/328D06M13/265D21H13/04D06M101/06
CPCD06M11/38D06M13/11D06M13/265D06M13/328D06M2101/06D21H13/04
Inventor 王立娟曹乐乐冯昊李坚
Owner NORTHEAST FORESTRY UNIVERSITY
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