Artificial timber

Abstract

An artificial timber comprises the following components in parts by weight: 35-50 parts of cellulose, 20-35 parts of hemicellulose and 15-35 parts of lignin, wherein the artificial timber has a density of 0.01-0.05 g/cm.sup.3. The preparing method comprises: (1) dissolving 15-35 parts by weight of lignin, 35-50 parts by weight of cellulose and 20-35 parts by weight of hemicellulose with an ionic liquid; (2) cleaning and replacing it with water to obtain a lignocellulose hydrogel; and (3) drying the lignocellulose hydrogel to obtain an artificial timber. The artificial timber prepared by the present invention is large in specific area, low in density, low in material energy consumption, moderate in condition and easy for operation. The artificial timber obtained by the present invention is regular in shape and is shaped like a sandy beige cylinder without obvious damage and deformation, which indicates that such artificial timber with high specific area has well molding capacity.

Claims

1. An artificial timber, comprising 42 parts of cellulose, 27 parts of hemicellulose and 28 parts of lignin in parts by weight, wherein: the artificial timber has: a density of 0.04 g/cm.sup.3; a surface area of 198 m.sup.2/g; a 24-hour water-absorbing expansion rate of 0.2%; a compressed yield stress of 4.40 MPa; a compression strength of 4.40 MPa; a compression resistance of the artificial timber is such that integrality is still maintained when suffering a deformation of greater than or equal to 80%; and a durability that the artificial timber will not disperse after being boiled in boiling water for 2 hours; the artificial timber is prepared by a method comprising steps of: (1) dissolving 28 parts by weight of lignin, 42 parts by weight of cellulose and 27 parts by weight of hemicellulose to form a lignocellulose; adding the lignocellulose into an ionic liquid selected from one of 1-butyl-3-methylimidazole hexafluorophosphate, 1-butyl-3-methylimidazole chloride, 1-allyl-3-methylimidazole chloride, 1-benzyl-3-methylimidazole chloride and 1-ethyl-3-methylimidazole phosphate; and heating and stirring at 120° C. for 15 hours to obtain a lignocellulose ionic liquid dispersion; (2) cleaning and replacing the ionic liquid with water to obtain a lignocellulose hydrogel; and (3) drying the lignocellulose hydrogel by one of critical point drying, freezing drying and supercritical drying to obtain an artificial timber; and the artificial timber is a composite structure formed by winding microparticle lignin with fibers, microparticle lignin can cause the fibers to be adhered to firmly combine the fibers with the microparticle lignin, and can bring about higher mechanical property than uniform single fibers.

2. The artificial timber in claim 1, wherein the water in step (2) is deionized water, distilled water or ultrapure water.

3. The artificial timber in claim 2, wherein step (2) is repeated 40 times, each time lasting for 80 hours.

4. The artificial timber in claim 3, wherein a drying time in step (3) is 100 hours.

Description

BRIEF DESCRIPTION OF FIGURES

(1) In order to clarify specific embodiments of the present invention or technical solutions in the prior art, the drawings required to be used in the description of the specific embodiments or prior art will be briefly introduced. In all drawings, similar elements or parts are generally marked with similar reference signs. In the drawings, respective elements or parts are unnecessarily drawn according to an actual proportion.

(2) FIG. 1 is a flowchart of the preparing method for an artificial timber of the present invention;

(3) FIG. 2 shows a scanning electron microscope image of the artificial timber prepared in Example 1 of the present invention;

(4) FIG. 3 shows a strain-stress curve graph of the artificial timber prepared in Examples 1-3 of the present invention;

(5) FIG. 4 shows a strain-stress curve graph for the artificial timber prepared in Example 4 of the present invention and a natural timber; and

(6) FIG. 5 is an SEM image of the artificial timber prepared in Example 2 of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(7) The present invention is further described in detail in combination with specific examples, and the given examples are merely intended to illuminate the present invention instead of limiting a scope of the present invention.

(8) It should be noted that unless otherwise stated, the technical terms or scientific terms used in the present application should have a general meaning understood by those skilled in the art of the present invention.

(9) The present invention provides an artificial timber, comprising the following components in parts by weight: 35-50 parts of cellulose, 20-35 parts of hemicellulose and 15-35 parts of lignin, and preferably comprising the following components in parts by weight: 42 parts of cellulose, 27 parts of hemicellulose and 28 parts of lignin.

(10) FIG. 1 is a flowchart of a preparing method for an artificial timber of the present invention. Referring to FIG. 1, the method for preparing the artificial timber of the present invention extracts the lignin from natural timber, and coagulates the lignin together with the cellulose and hemicellulose, so as to form an artificial timber, and the method comprises the following steps:

(11) Step S1: weighing the cellulose, hemicellulose and lignin according to required weights and mixing to form a lignocellulose.

(12) Step S2, adding the lignocellulose into an ionic liquid and heating and stirring for dissolving to obtain a lignocellulose ionic liquid dispersion.

(13) Wherein, the ionic liquid is selected from one or more of 1-butyl-3-methylimidazole hexafluorophosphate, 1-butyl-3-methylimidazole chloride, 1-allyl-3-methylimidazole chloride, 1-benzyl-3-methylimidazole chloride and 1-ethyl-3-methylimidazole phosphate under room temperature.

(14) Wherein a temperature of the heating and stirring is 50° C.-200° C., and the heating and stirring time is 2-24 h.

(15) Step S3, cleaning and replacing the lignocellulose ionic liquid dispersion with water to obtain a lignocellulose hydrogel.

(16) Wherein, the water comprises deionized water, distilled water or ultrapure water.

(17) Wherein, the number of times of the cleaning and replacing is 1-99 times, and time for every time is 0.5-99 h.

(18) Step S4, drying the lignocellulose hydrogel to obtain an artificial timber. Wherein the drying processing comprises any one of critical point drying, freezing drying or supercritical drying, and the drying time is 1 h-1000 h.

Example 1

(19) The artificial timber of the present example comprises the following components in parts by weight: 35 parts of cellulose, 20 parts of hemicellulose and 15 parts of lignin, and the preparing method comprises the steps as follows:

(20) 1. Weighing the cellulose, hemicellulose and lignin according to the required weights and mixing to form a lignocellulose, adding 7 g of the lignocellulose into 100 ml of 1-butyl-3-methylimidazole hexafluorophosphate, and heating and stirring for dissolving to obtain a lignocellulose ionic liquid dispersion, wherein the temperature of the heating and stirring is 50° C., and the time for heating and stirring is 24 h;

(21) 2. cleaning and replacing the lignocellulose ionic liquid dispersion with 500 ml of deionized water to obtain a lignocellulose hydrogel, wherein the number of times of the cleaning and replacing is 1 time, and time for every time is 99 h;

(22) 3. performing critical point drying on the lignocellulose hydrogel to obtain an artificial timber according to the present invention, wherein the drying time is 1 h.

Example 2

(23) The artificial timber of the present example comprises the following components in parts by weight: 38 parts of cellulose, 23 parts of hemicellulose and 19 parts of lignin, and the preparing method comprises the steps as follows:

(24) 1. Weighing the cellulose, hemicellulose and lignin according to the required weights and mixing to form a lignocellulose, adding 8 g of the lignocellulose into 100 ml of 1-butyl-3-methylimidazole chloride, and heating and stirring for dissolving to obtain a lignocellulose ionic liquid dispersion, wherein the temperature of the heating and stirring is 90° C., and the time for heating and stirring is 18 h;

(25) 2. cleaning and replacing the lignocellulose ionic liquid dispersion with 500 ml of distilled water to obtain a lignocellulose hydrogel, wherein the number of times of the cleaning and replacing is 5 times, and the time for every time is 90 h;

(26) 3. performing freezing drying on the lignocellulose hydrogel to obtain an artificial timber according to the present invention, wherein the drying time is 50 h.

Example 3

(27) The artificial timber of the present example comprises the following components in parts by weight: 42 parts of cellulose, 27 parts of hemicellulose and 28 parts of lignin, and the preparing method comprises the steps as follows:

(28) 1. Weighing the cellulose, hemicellulose and lignin according to the required weights and mixing to form a lignocellulose, adding 9.7 g of the lignocellulose into 100 ml of 1-allyl-3-methylimidazole chloride, and heating and stirring for dissolving to obtain a lignocellulose ionic liquid dispersion, wherein the temperature of the heating and stirring is 120° C., and the time for heating and stirring is 15 h;

(29) 2. cleaning and replacing the lignocellulose ionic liquid dispersion with 800 ml of ultrapure water to obtain a lignocellulose hydrogel, wherein the number of times of the cleaning and replacing is 40 times, and the time for every time is 80 h;

(30) 3. performing supercritical drying on the lignocellulose hydrogel to obtain an artificial timber according to the present invention, wherein the drying time is 100 h.

Example 4

(31) The artificial timber of the present example comprises the following components in parts by weight: 44 parts of cellulose, 29 parts of hemicellulose and 32 parts of lignin, and the preparing method comprises the steps as follows:

(32) 1. Weighing the cellulose, hemicellulose and lignin according to the required weights and mixing to form a lignocellulose, adding 10.5 g of the lignocellulose into 120 ml of 1-benzyl-3-methylimidazole chloride, and heating and stirring for dissolving to obtain a lignocellulose ionic liquid dispersion, wherein the temperature of the heating and stirring is 150° C., and the time for heating and stirring is 10 h;

(33) 2. cleaning and replacing the lignocellulose ionic liquid dispersion with 1000 ml of deionized water to obtain a lignocellulose hydrogel, wherein the number of times of the cleaning and replacing is 60 times, and the time for every time is 12 h;

(34) 3. performing critical point drying on the lignocellulose hydrogel to obtain an artificial timber according to the present invention, wherein the drying time is 500 h.

Example 5

(35) The artificial timber of the present example comprises the following components in parts by weight: 50 parts of cellulose, 35 parts of hemicellulose and 35 parts of lignin, and the preparing method comprises the steps as follows:

(36) 1. Weighing the cellulose, hemicellulose and lignin according to the required weights and mixing to form lignocellulose, adding 12 g of the lignocellulose into 150 ml of 1-ethyl-3-methylimidazole phosphate, and heating and stirring for dissolving to obtain a lignocellulose ionic liquid dispersion, wherein the temperature of the heating and stirring is 200° C., and the time for heating and stirring is 5 h;

(37) 2. cleaning and replacing the lignocellulose ionic liquid dispersion with 1000 ml of ultrapure water to obtain a lignocellulose hydrogel, wherein the number of times of the cleaning and replacing is 99 times, and the time for every time is 0.5 h;

(38) 3. performing supercritical drying on the lignocellulose hydrogel to obtain an artificial timber according to the present invention, wherein the drying time is 1000 h.

(39) Performance Test

(40) For the artificial timber prepared in Examples 1-3 of the present invention, four samples are taken respectively for compression performance test, and test conditions and results are shown in Table 1.

(41) TABLE-US-00001 TABLE 1 Compression Compression Sample Maximal yield Compression Sample modulus/ Item diameter/mm force/kN stress/MPa strength/MPa height/mm kN .Math. m.sup.−2 Example 1 19.60 1.00 0.69 3.31 6.70 1282 Example 2 19.00 1.00 3.52 3.52 8.30 25380 Example 3 17.00 1.00 4.40 4.40 5.80 42211

(42) For the artificial timber prepared in Examples 1-3 of the present invention, four samples are taken respectively for tests on sample density, water absorbing expansion rate, compression resistance and durability, and the results are shown in Table 2.

(43) TABLE-US-00002 TABLE 2 Sample Water density Specific absorbing Compression Item g/cm.sup.3 area m.sup.2/g expansion rate resistance Durability Example 1 0.024 235.9 0.5% Integrity is still Not dispersing maintained when after being boiled deformation is larger in boiling water than >80% for 2 h Example 2 0.029 226.7 0.4% Integrity is still Not dispersing maintained when after being boiled deformation is larger in boiling water than >80% for 2 h Example 3 0.040 198 0.2% Integrity is still Not dispersing maintained when after being boiled deformation is larger in boiling water than >80% for 2 h Note: 1. the method for testing the water absorbing expansion rate is as follows: a dry sample is soaked for 24 h in a position lower than the water surface by 3 cm by using a water tank, then the change of the sample volume is tested, and the water absorbing expansion rate is the ratio of the volume change value to the volume value of the original material; 2. the specific area is tested by an isothermal nitrogen gas desorption and absorption experiment and the detecting temperature is 77 K.

(44) FIG. 3 shows a strain-stress curve graph for the artificial timbers prepared in Examples 1-3 of the present invention. Referring to FIG. 3 and Table 1, it can be seen that the artificial timber prepared by the method of the present invention has a higher specific area.

(45) Rift grain compression test is performed on the artificial timber prepared by the present invention and the natural timber respectively to compare the mechanical properties of them. The artificial timber prepared by Example 4 and the natural timber are taken, to respectively serve as rift grain compression test pieces, wherein the cross-sectional size of the artificial timber and the natural timber is 16 mm×16 mm, and the length is 270 mm.

(46) The timber rift grain compression mechanical test adopts a universal mechanics test machine, and in order to ensure press rod stability, the universal mechanics test machine is equipped with a rift grain compression die. In order to obtain the maximal rift grain compression of the samples and a more appropriate rift grain compression rate for multidimensional bending, a rift grain compression speed is set to be 2 mm/min, and the artificial timber and the natural timber are subjected to rift grain compression respectively.

(47) The test data is analyzed by a regression analysis method, and a regression relation function expression between a dependent variable and an independent variable is constructed with a statistical method. The strain-stress relation of the timber in each stage is calculated by an image data analysis software package “S-PLUS.”

(48) FIG. 4 shows a strain-stress curve graph for the artificial timber prepared in Example 4 of the present invention and a natural timber. Referring to FIG. 4, by testing the stress and strain values of the artificial timber and the natural timber, the stress-strain curve corresponding thereto is shown in FIG. 4. It can be seen that during the compression test, the artificial timber generally shows higher stress than the natural timber under the same stress. During the test process, when the strain is about 1.5%, the natural timber has ruptured, and is severely damaged when the strain is more than 3% (the test ends). But in the whole test process, no obvious damage to the artificial timber of the present invention is caused, and it can be seen that the tenacity of the artificial timber is obviously higher than the natural timber.

(49) FIG. 5 is an SEM image of the artificial timber prepared in Example 2 of the present invention. From FIG. 5, it can be seen that the structure of the artificial timber is different from the single fiber structure, but is a composite structure formed by winding the microparticle lignin with lots of fibers, the microparticle lignin can cause the fibers to be adhered to firmly combine the fibers with the microparticle lignin, and can bring about higher mechanical property than uniform single fibers.

(50) It should be noted finally that the above respective examples are merely intended to explain the technical solution of the present invention rather than limiting the same. Although the present invention is explained in detail with reference to the foregoing respective embodiments, those ordinary skilled in the art should understand that the technical solutions cited by the foregoing respective embodiments can still be amended, or part or all of technical features therein can be equivalently replaced; while these amendments or replacements do not cause the essence of the corresponding technical solutions to be departed from the scope of the technical solutions of respective embodiments of the present invention, and they should be covered in the scope of claims and specification of the present invention.