Preparation method of industrial alkali lignin/polyvinyl alcohol cross-linked thin film

A technology of industrial alkali lignin and polyvinyl alcohol, applied in the field of polymer film materials

Inactive Publication Date: 2013-12-25
NORTHEAST FORESTRY UNIVERSITY +2
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  • Abstract
  • Description
  • Claims
  • Application Information

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  • Preparation method of industrial alkali lignin/polyvinyl alcohol cross-linked thin film
  • Preparation method of industrial alkali lignin/polyvinyl alcohol cross-linked thin film
  • Preparation method of industrial alkali lignin/polyvinyl alcohol cross-linked thin film

Examples

Experimental program
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Effect test

Embodiment 1

[0018] Industrial alkali lignin dissolves a certain amount of crude lignin with 0.1moL / L NaOH solution, stirs it under the mixer for 2 hours, and then centrifuges it with a centrifuge. After filtering the obtained liquid through a layer of filter cloth, it is directly spray dried with a spray dryer , the resulting solid powder is the alkali lignin required for the experiment.

[0019] Weigh 8g of PVA and 2g of alkali lignin into a three-necked flask, add 195g of water, heat and stir in a water bath at 90°C for 50min. Then add 2 mL of formaldehyde with a mass fraction of 37% to 40%, and carry out the crosslinking reaction for 30 minutes. After the stirring was completed, vacuum defoaming was performed at room temperature, and a film was cast on a glass plate. Dry naturally at room temperature to obtain the desired film. After cooling for a while, vacuum defoaming, pour it on a glass plate, then scrape it with a scraper to form a film, and after natural drying, peel off the fi...

Embodiment 2

[0022] Weigh 7g of PVA and 3g of alkali lignin into a three-necked flask, add 195g of water, heat and stir in a water bath at 90°C for 50min. Then add 2 mL of formaldehyde with a mass fraction of 37% to 40%, and carry out the crosslinking reaction for 30 minutes. After the stirring was completed, vacuum defoaming was performed at room temperature, and a film was cast on a glass plate. Dry naturally at room temperature to obtain the desired film. After cooling for a while, vacuum defoaming, pour it on a glass plate, then use a scraper to scrape it into a film, and after natural drying, peel off the film to obtain an alkali lignin / PVA co-film.

[0023] Tensile properties of the film The elongation at break is 182.26%, the tensile strength is 32.62MPa, and the oxygen permeability is 15.80×10 -5 cm 3 / m 2 ·d·Pa, carbon dioxide air permeability 11.40×10 -5 cm 3 / m 2 · d · Pa.

Embodiment 3

[0025] Weigh 6g of PVA and 4g of alkali lignin into a three-necked flask, add 195g of water, heat and stir in a water bath at 90°C for 50min. Then add 2 mL of formaldehyde with a mass fraction of 37% to 40%, and carry out the crosslinking reaction for 30 minutes. After the stirring was completed, vacuum defoaming was performed at room temperature, and a film was cast on a glass plate. Dry naturally at room temperature to obtain the desired film. After cooling for a while, vacuum defoaming, pour it on a glass plate, then scrape it with a scraper to form a film, and after natural drying, peel off the film to obtain an alkali lignin / PVA film.

[0026] Tensile properties of the film The elongation at break is 158.38%, the tensile strength is 25.93MPa, and the oxygen permeability is 13.1×10 -5 cm 3 / m 2 ·d·Pa, carbon dioxide gas permeability 9.35×10 -5 cm 3 / m 2 · d · Pa.

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Abstract

Alkali lignin is a main by-product of the papermaking industry of our country, and sever environmental pollution will be caused by direct discharge of alkali lignin. The invention discloses a preparation method of an industrial alkali lignin/polyvinyl alcohol cross-linked thin film, so as to increase utilization ratio of lignin, reduce environmental pollution and ease the resource crisis. The industrial alkali lignin/polyvinyl alcohol cross-linked thin film is prepared by following steps, industrial alkali lignin and polyvinyl alcohol (PVA) are taken as raw materials, and are crosslinked by a cross-linking agent; and then the mixture is subjected to tape casting so as to obtain the alkali lignin/polyvinyl alcohol cross-linked thin film. An optimized preparation technology is obtained based on mechanical properties. The mechanical properties of the industrial alkali lignin/polyvinyl alcohol cross-linked thin film are better than that of industrial polyvinyl alcohol films; absorption rate on ultraviolet light is about 100%; and transmittance is reduced to a certain degree. Blending compatibility of alkali lignin and PVA is excellent; the surfaces of alkali lignin and polyvinyl alcohol thin films, which are prepared by blending or crosslinking, are smooth; and phase separation is not caused. Thermal stability of the industrial alkali lignin/PVA cross-linked thin film is increased. The industrial alkali lignin/PVA cross-linked thin film can be used as an excellent ultraviolet absorption material, and it is possible to develop a novel specific packaging material or mulching film.

Description

Technical field: [0001] The invention is a polymer film material prepared by crosslinking industrial alkali lignin and polyvinyl alcohol through formaldehyde. Background technique: [0002] Industrial alkali lignin is the main by-product of my country's paper industry. Direct discharge will cause serious environmental pollution. Moreover, alkali lignin is an aromatic renewable resource, and a large amount of pollutant discharge is a great waste of resources. Therefore, the development and utilization of alkali lignin can not only reduce environmental pollution, but also alleviate resource crisis and maintain sustainable development. Lignin takes phenylpropane as the main structure, contains phenolic hydroxyl group, alcoholic hydroxyl group, methoxyl group, carbonyl group, aldehyde group, ethylenic bond and other groups, can carry out various chemical reactions, and because it contains many aromatic rings, it has the function of shielding ultraviolet radiation. ability, but ...

Claims

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Application Information

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IPC IPC(8): C08J5/18C08J3/24C08L29/04C08L97/00
Inventor 方桂珍苏玲马艳丽徐超曲方玉
Owner NORTHEAST FORESTRY UNIVERSITY
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