Preparation method of cellulose nano-fiber/polylactic acid composite membrane

A technology of cellulose fibers and nanofibers, which is applied in fiber raw material processing, textiles and papermaking, etc., can solve the problems of poor toughness, high glass transition temperature, lack of flexibility and elasticity, etc., and achieve high crystallinity and uniform diameter distribution Effect

Inactive Publication Date: 2013-11-13
NANJING FORESTRY UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the glass transition temperature of biodegradable polylactic acid is higher than room temperature. Below this temperature, polylactic acid is brittle like glass, hard and tough, and lacks flexibility and elasticity.
In addition, the chemical structure of polylactic acid lacks reactive functional groups and is not hydrophilic, resulting in slow degradation of polylactic acid. Therefore, it is necessary to modify polylactic acid to improve its performance and application range

Method used

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  • Preparation method of cellulose nano-fiber/polylactic acid composite membrane
  • Preparation method of cellulose nano-fiber/polylactic acid composite membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] The preparation of cellulose nanofiber / polylactic acid composite film comprises the following steps:

[0038] Step 1) Raw material treatment: use benzene alcohol extraction to remove impurities contained in lignocellulosic raw materials, including terpenes, fats, waxes, sugars, tannins, polyphenols, pigments, water-soluble polysaccharides, salts class of substances.

[0039] The specific method of using benzene alcohol extraction to remove impurities contained in lignocellulosic raw materials is to weigh 10g of wood flour on an electronic balance, place it in a Soxhlet extractor, measure 100ml of toluene and 50ml of ethanol Mix, utilize the solution that the volume ratio of toluene and ethanol is 2:1 to carry out the extraction of wood powder for 6 hours. Remove impurities therein, after extraction, wash with ethanol, filter and dry at room temperature, take it after it is completely dry.

[0040] Step 2) Chemical treatment: put the dried wood powder in 400ml of disti...

Embodiment 2

[0048] Embodiment 2: the process of preparing nanocellulose from absorbent cotton:

[0049] Put 5g of absorbent cotton, 500ml of distilled water, 4.6g of sodium chlorite and 3.8ml of glacial acetic acid in a beaker, and treat the beaker in a water bath at 75°C for 1 hour. During this process, keep stirring and The beaker should be sealed. This process was repeated 2 times to remove residual lignin. It was then treated with 5% potassium hydroxide at 90°C for 2 hours to remove residual hemicellulose. Treat the absorbent cotton with 1% hydrochloric acid for 3 hours. Then, it is processed by mechanical treatment to obtain nanocellulose. The mechanical treatment method is the same as that of wood flour.

Embodiment 3

[0050] Embodiment 3: the preparation of composite material:

[0051] Dry polylactic acid in a vacuum oven at 45°C for 24 hours, weigh 5g of polylactic acid and 50ml of methylene chloride and pour them into a beaker, place the beaker in a magnetic heating stirrer and stir at room temperature until the polylactic acid particles are completely dissolved , about 2 hours. Immerse four identical nanocellulose membranes in the polylactic acid solution, take out the samples after immersion for 2h, 4h, 6h and 8h respectively, take out the samples and dry them at room temperature for 12 hours, and then dry them in a vacuum oven at 60°C for 24 hours , to obtain nanocellulose / polylactic acid film.

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Abstract

The invention provides a preparation method of a cellulose nano-fiber / polylactic acid composite membrane. The preparation method comprises the following steps of: (1) treating raw materials; (2) performing chemical treatment; (3) performing mechanical treatment; (4) preparing a nano cellulose membrane; (5) preparing a nano cellulose / polylactic acid composite membrane material by using a mixing and dissolving method or an immersion method. The preparation method has the advantages that lignin and most of hemicellulose are removed by using a chemical method, and under a water wet swelling condition, water fills the positions in which most of the hemicellulose and the lignin are removed, so that the hydrogen bond acting force among fibrillae is reduced; then lignocellulose nano fibrillae with uniform morphological sizes and mesh gangles are prepared by adopting mechanical treatment. The nano celluloses prepared by grinding for 30 minutes and homogenizing are small in diameter size and are uniformly distributed, the diameters of the nano fibrillae is 15-50nm, and the length-diameter ratio is high and reaches 1200. The cellulose nano-fiber / polylactic acid composite membrane can be used as a substitute and the like for a flexible display, electronic paper, a solar battery, a flexible circuit and a glass substrate.

Description

technical field [0001] The invention relates to a preparation method of a cellulose nanofiber / epoxy resin composite film, which belongs to the technical field of composite materials. Background technique [0002] With the rapid development of optoelectronic technology, higher requirements are put forward for the substrate materials of electrical equipment such as liquid crystal displays. The preparation of flexible substrate materials with high light transmittance, high strength and low thermal expansion has become the focus of research. Plastics are more flexible, but have a higher coefficient of thermal expansion. Glass has high heat resistance, but is less flexible. Cellulose nanofibers are fibrous aggregates composed of cellulose unit cells, including cellulose basic fibrils and microfibrils, with a diameter between 2 and 50 nm. Cellulose nanofibers have excellent mechanical properties. In theory, their Young's modulus can reach 15GPa, and they come from a wide range...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J5/18C08J7/00C08L67/04C08L1/02D21C5/00
Inventor 李大纲李明珠潘佳陈振东李雪婷胡月薛莹莹
Owner NANJING FORESTRY UNIV
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