CN118756514B - A method for preparing cellulose derivatives using crop straw as raw material - Google Patents
A method for preparing cellulose derivatives using crop straw as raw material Download PDFInfo
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- CN118756514B CN118756514B CN202411237289.9A CN202411237289A CN118756514B CN 118756514 B CN118756514 B CN 118756514B CN 202411237289 A CN202411237289 A CN 202411237289A CN 118756514 B CN118756514 B CN 118756514B
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- crop straw
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- deionized water
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- 239000001913 cellulose Substances 0.000 title claims abstract description 145
- 229920002678 cellulose Polymers 0.000 title claims abstract description 145
- 239000010902 straw Substances 0.000 title claims abstract description 135
- 239000002994 raw material Substances 0.000 title claims abstract description 35
- 238000000034 method Methods 0.000 title claims abstract description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 68
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical class O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 62
- 239000003063 flame retardant Substances 0.000 claims abstract description 52
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 claims abstract description 49
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 27
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims abstract description 27
- 239000000945 filler Substances 0.000 claims abstract description 24
- 239000002131 composite material Substances 0.000 claims abstract description 23
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims abstract description 22
- 238000002156 mixing Methods 0.000 claims abstract description 17
- 239000003607 modifier Substances 0.000 claims abstract description 17
- 239000000292 calcium oxide Substances 0.000 claims abstract description 14
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims abstract description 14
- 230000001007 puffing effect Effects 0.000 claims abstract description 14
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910000029 sodium carbonate Inorganic materials 0.000 claims abstract description 11
- 230000003113 alkalizing effect Effects 0.000 claims abstract description 9
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 66
- 238000003756 stirring Methods 0.000 claims description 64
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 57
- 239000008367 deionised water Substances 0.000 claims description 56
- 229910021641 deionized water Inorganic materials 0.000 claims description 56
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 50
- 238000005406 washing Methods 0.000 claims description 34
- GJLPUBMCTFOXHD-UPHRSURJSA-N (11z)-1$l^{2},2$l^{2},3$l^{2},4$l^{2},5$l^{2},6$l^{2},7$l^{2},8$l^{2},9$l^{2},10$l^{2}-decaboracyclododec-11-ene Chemical compound [B]1[B][B][B][B][B]\C=C/[B][B][B][B]1 GJLPUBMCTFOXHD-UPHRSURJSA-N 0.000 claims description 30
- 238000001035 drying Methods 0.000 claims description 27
- 238000001914 filtration Methods 0.000 claims description 27
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 16
- 239000007864 aqueous solution Substances 0.000 claims description 15
- 238000006243 chemical reaction Methods 0.000 claims description 14
- 229920000877 Melamine resin Polymers 0.000 claims description 12
- JLTDJTHDQAWBAV-UHFFFAOYSA-N N,N-dimethylaniline Chemical compound CN(C)C1=CC=CC=C1 JLTDJTHDQAWBAV-UHFFFAOYSA-N 0.000 claims description 12
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 claims description 12
- 239000012074 organic phase Substances 0.000 claims description 12
- 239000000843 powder Substances 0.000 claims description 12
- FYSNRJHAOHDILO-UHFFFAOYSA-N thionyl chloride Chemical compound ClS(Cl)=O FYSNRJHAOHDILO-UHFFFAOYSA-N 0.000 claims description 12
- KSZVOXHGCKKOLL-UHFFFAOYSA-N 4-Ethynyltoluene Chemical compound CC1=CC=C(C#C)C=C1 KSZVOXHGCKKOLL-UHFFFAOYSA-N 0.000 claims description 11
- 238000001816 cooling Methods 0.000 claims description 11
- SXRSQZLOMIGNAQ-UHFFFAOYSA-N Glutaraldehyde Chemical compound O=CCCCC=O SXRSQZLOMIGNAQ-UHFFFAOYSA-N 0.000 claims description 10
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 10
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 claims description 10
- 238000001125 extrusion Methods 0.000 claims description 10
- 150000003943 catecholamines Chemical class 0.000 claims description 9
- 239000007787 solid Substances 0.000 claims description 9
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 claims description 8
- WGLPBDUCMAPZCE-UHFFFAOYSA-N chromium trioxide Inorganic materials O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims description 8
- 239000007800 oxidant agent Substances 0.000 claims description 8
- 230000001590 oxidative effect Effects 0.000 claims description 8
- YIEDHPBKGZGLIK-UHFFFAOYSA-L tetrakis(hydroxymethyl)phosphanium;sulfate Chemical compound [O-]S([O-])(=O)=O.OC[P+](CO)(CO)CO.OC[P+](CO)(CO)CO YIEDHPBKGZGLIK-UHFFFAOYSA-L 0.000 claims description 7
- 229940117975 chromium trioxide Drugs 0.000 claims description 6
- GAMDZJFZMJECOS-UHFFFAOYSA-N chromium(6+);oxygen(2-) Chemical group [O-2].[O-2].[O-2].[Cr+6] GAMDZJFZMJECOS-UHFFFAOYSA-N 0.000 claims description 6
- 239000007853 buffer solution Substances 0.000 claims description 5
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 5
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 4
- 230000004913 activation Effects 0.000 claims description 4
- 238000000227 grinding Methods 0.000 claims description 4
- 239000002904 solvent Substances 0.000 claims description 4
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 3
- 229910000423 chromium oxide Inorganic materials 0.000 claims description 2
- 238000000151 deposition Methods 0.000 claims description 2
- 229920002488 Hemicellulose Polymers 0.000 abstract description 13
- 229920005610 lignin Polymers 0.000 abstract description 13
- 238000000605 extraction Methods 0.000 abstract description 9
- 239000000463 material Substances 0.000 abstract description 9
- 238000002360 preparation method Methods 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 22
- 239000002585 base Substances 0.000 description 11
- 238000005886 esterification reaction Methods 0.000 description 11
- 239000000178 monomer Substances 0.000 description 11
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 8
- -1 nitrogen-phosphorus-aluminum Chemical compound 0.000 description 7
- 230000001360 synchronised effect Effects 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 239000005909 Kieselgur Substances 0.000 description 6
- 229910021645 metal ion Inorganic materials 0.000 description 6
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 125000003172 aldehyde group Chemical group 0.000 description 4
- 210000002421 cell wall Anatomy 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 230000032050 esterification Effects 0.000 description 4
- 238000004108 freeze drying Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000006460 hydrolysis reaction Methods 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 238000000354 decomposition reaction Methods 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 3
- 238000006731 degradation reaction Methods 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000007935 neutral effect Effects 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 2
- 230000021523 carboxylation Effects 0.000 description 2
- 238000006473 carboxylation reaction Methods 0.000 description 2
- 210000002390 cell membrane structure Anatomy 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000004132 cross linking Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000007062 hydrolysis Effects 0.000 description 2
- 229910010272 inorganic material Inorganic materials 0.000 description 2
- 239000011147 inorganic material Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000004753 textile Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 229920003043 Cellulose fiber Polymers 0.000 description 1
- 239000002262 Schiff base Substances 0.000 description 1
- 150000004753 Schiff bases Chemical class 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 150000001345 alkine derivatives Chemical class 0.000 description 1
- 125000000304 alkynyl group Chemical group 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005271 boronizing Methods 0.000 description 1
- YCIMNLLNPGFGHC-UHFFFAOYSA-N catechol Chemical group OC1=CC=CC=C1O YCIMNLLNPGFGHC-UHFFFAOYSA-N 0.000 description 1
- 238000007385 chemical modification Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000006266 etherification reaction Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 125000002791 glucosyl group Chemical group C1([C@H](O)[C@@H](O)[C@H](O)[C@H](O1)CO)* 0.000 description 1
- 150000004676 glycans Chemical class 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 238000006713 insertion reaction Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- VHRYZQNGTZXDNX-UHFFFAOYSA-N methacryloyl chloride Chemical compound CC(=C)C(Cl)=O VHRYZQNGTZXDNX-UHFFFAOYSA-N 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 210000001724 microfibril Anatomy 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 230000000269 nucleophilic effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/001—Modification of pulp properties
- D21C9/002—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
- D21C9/004—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives inorganic compounds
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C3/00—Pulping cellulose-containing materials
- D21C3/02—Pulping cellulose-containing materials with inorganic bases or alkaline reacting compounds, e.g. sulfate processes
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/001—Modification of pulp properties
- D21C9/002—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
- D21C9/005—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives organic compounds
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
Abstract
本发明公开了一种以农作物秸秆为原料制备纤维素衍生物的方法，属于涉及秸秆纤维素材料技术领域，制备方法包括如下步骤：将农作物秸秆粉碎、膨化后，得到农作物秸秆原料；将农作物秸秆原料经处理剂处理后，得到农作物秸秆基纤维素；农作物秸秆基纤维素经碱化处理后，再与改性剂、复合填料混合，得到纤维素衍生物。改性硅藻土嵌入到硅溶胶体系中，具有优异的防水性能，避免阻燃剂易吸水分解；羧基化邻碳硼烷接枝在纤维素上，能够提高纤维素衍生物的耐热稳定性；碳酸钠、氧化钙联合处理农作物秸秆，可以有效地去除农作物秸秆中的木质素和半纤维素，且农作物秸秆膨化产生的多孔结构增大与预处理剂的接触面积，增加纤维素的提取率。The invention discloses a method for preparing cellulose derivatives using crop straw as raw material, which belongs to the technical field of straw cellulose materials. The preparation method comprises the following steps: crushing and puffing the crop straw to obtain the crop straw raw material; treating the crop straw raw material with a treatment agent to obtain the crop straw-based cellulose; alkalizing the crop straw-based cellulose, and then mixing it with a modifier and a composite filler to obtain a cellulose derivative. Modified diatomaceous earth is embedded in a silica sol system, which has excellent waterproof performance and avoids the flame retardant from easily absorbing water and decomposing; carboxylated ortho-carborane is grafted on cellulose to improve the heat resistance stability of cellulose derivatives; sodium carbonate and calcium oxide are used to jointly treat the crop straw to effectively remove lignin and hemicellulose in the crop straw, and the porous structure generated by the puffing of the crop straw increases the contact area with the pretreatment agent and increases the extraction rate of cellulose.
Description
Technical Field
The invention relates to the technical field of straw cellulose materials, in particular to a method for preparing cellulose derivatives by taking crop straws as raw materials.
Background
The crop straw contains a large amount of cellulose, hemicellulose and lignin, the cellulose is polysaccharide, the cellulose accounts for 30-50% of the total amount in the straw, the chemical structure is that glucose units are connected through beta-1, 4-glycosidic bonds to form long chains, on the microstructure, cellulose molecular chains are further tightly packed into microfibrils through hydrogen bonds to form cellulose fibers, the cellulose is extracted from the crop straw and is widely used as a renewable and biodegradable raw material in industry and daily life, the functional structure of the cellulose is modified, such as oxidation, esterification, etherification, grafting and the like, the recycling of the crop straw is realized, and the modified cellulose material is applied to the fields of food, packaging, environmental protection, medical treatment, textile and the like.
Cellulose is extracted from crop straws, and then the cellulose is subjected to chemical modification, so that the obtained fiber bundle derivative is widely applied to the fields of food, packaging, environmental protection, textile and the like, but in the crop straws, a lignocellulose composition is wrapped around the cellulose to form a complex natural structure, so that the extraction and the utilization of the cellulose are hindered, and a large number of intermolecular and intramolecular hydrogen bonds exist on a molecular chain of the cellulose of the crop straws, so that the cellulose has low reactivity, is not easy to dissolve and is difficult to fully utilize, and the heat resistance and the flame retardance of the cellulose are poor, so that the application range of the cellulose derivative is influenced.
Disclosure of Invention
The invention aims to provide a method for preparing a cellulose derivative by using crop straws as a raw material and application thereof, wherein the nitrogen-phosphorus-aluminum flame retardant is formed, contains N, P, al elements, has excellent flame retardant property, further can be used for preparing the cellulose derivative, is deposited on the surface of diatomite to improve the flame retardant property, the flame retardant powder can fill or plug a porous structure of the diatomite to prevent metal ions in the diatomite from falling off to reduce the cellulose derivative property, the modified diatomite is embedded into a silica sol system to endow the silica sol with excellent waterproof property to prevent the flame retardant from easily absorbing water and reducing the flame retardant property, carboxylated o-carborane reacts with citric acid to form a modifier which can be subjected to esterification reaction with crop straw-based cellulose to enable carboxylated o-carborane to be grafted on the crop straw-based cellulose more easily, and has higher thermal stability, and after the cellulose is subjected to esterification modification, the crystallinity of the crop straw-based cellulose can be reduced, the activity and the degradation property of the cellulose derivative are improved, and the binding force with a compound filler is increased.
The invention aims at solving the technical problems that in crop straws, a lignocellulose composition is wrapped around cellulose to form a complex natural structure, extraction and utilization of the cellulose are hindered, and a large number of intermolecular and intramolecular hydrogen bonds exist on a molecular chain of cellulose of the crop straws, so that the cellulose has low reactivity, is not easy to dissolve and is difficult to fully utilize, and the cellulose has poor heat resistance and flame retardance and influences the application range of cellulose derivatives.
In order to achieve the above purpose, the present invention provides the following technical solutions:
a method for preparing cellulose derivatives by using crop straws as raw materials comprises the following steps:
s1, crushing and puffing crop straws to obtain crop straw raw materials;
The puffing machine is used for carrying out boronizing treatment on the crop straws, so that waxy films and cell walls on the surfaces of the crop straws are broken, hemicellulose covered on cellulose is separated from lignin structures, further extraction and separation of cellulose in the crop straws are facilitated, and the crop straws are discharged under the action of high temperature, high pressure and high shearing force in the extrusion cavity, so that the cell walls and cell membrane structures of the crop straws are damaged, and the surfaces of the crop straws are of porous structures.
S2, treating the crop straw raw material by a treating agent to obtain crop straw base cellulose;
The sodium carbonate and the calcium oxide in the treating agent have the characteristics of high safety, low corrosiveness and lower cost, are used for replacing the conventional sodium hydroxide to treat straws, reduce the generation of waste liquid, improve the concentration of hydroxyl in the pretreatment agent through double decomposition reaction, effectively remove lignin and hemicellulose in crop straws, and increase the contact area between the porous structure generated by the swelling of the crop straws and the pretreatment agent and increase the extraction rate of cellulose.
Further, the dosage ratio of the crop straw raw material to the treating agent is (4-6) g (70-80) mL.
S3, after alkalizing the crop straw base cellulose, mixing the crop straw base cellulose with a modifier and a composite filler to obtain a cellulose derivative.
The hydroxyl contained in the alkalized crop straw-based cellulose can be subjected to esterification reaction with the carboxyl of citric acid in the modifier to form a cellulose derivative, and the cellulose derivative has good heat-resistant stability and mechanical strength.
Further, the mass ratio of the alkalized crop straw base cellulose to the modifier to the composite filler is (60-80): 45-55): 1-3.
Further, the specific steps of crushing and puffing the crop straws are that the crop straws are put into a crusher to be crushed, then are put into a double-screw extrusion puffing machine to be treated, and are dried for 10-20min at 45-50 ℃ to obtain the crop straw raw material.
Further, the temperature of the twin-screw extruder is 120-130 ℃, the screw rotating speed is 140-150r/min, the deionized water flow rate is 500-520g/h, and the feeding speed is 600-620g/h.
Further, the treating agent is prepared by mixing calcium oxide, sodium carbonate and deionized water according to the dosage ratio of (0.5-1.5) g (2.2-2.4) g (60-80) mL.
Further, the alkalization treatment specifically comprises the steps of adding crop straw-based cellulose into deionized water, uniformly stirring, adding 60% sodium hydroxide aqueous solution by mass fraction, alkalizing at 30-40 ℃ for 0.5-1h, filtering, and washing to obtain the alkalized crop straw-based cellulose.
Further, the dosage ratio of the crop straw base cellulose, the deionized water and the sodium hydroxide aqueous solution is (0.1-0.3) g (8-12) mL (0.3-0.7) mL.
Further, the composite filler is prepared by depositing a flame retardant on the surface of diatomite and then mixing the diatomite with silica sol, and is specifically prepared by the following steps:
A1. Adding diatomite and catecholamine into Tirs-HCl buffer solution with pH of 8.5, stirring and reacting for 24 hours, filtering, washing with ethanol for 3 times, washing with deionized water for 3 times, drying in a 60 ℃ oven for 10min to obtain pretreated diatomite, grinding a flame retardant into powder, adding into deionized water, uniformly stirring, adding pretreated diatomite, stirring for 30min at 45 ℃, cooling to room temperature, filtering, washing with deionized water for 3 times, and drying in a 70 ℃ oven for 8min to obtain modified diatomite.
The diatomite surface contains silicon hydroxyl groups and catecholamine, so that catecholamine is coated on the diatomite surface, the carried catechol groups endow the diatomite with excellent adhesiveness, the diatomite has a higher pore structure and good adsorption performance, the diatomite surface can be adsorbed with flame retardant powder, the flame retardant powder can fill or plug the porous structure of the diatomite, and the hydroxyl groups contained in the flame retardant can fix metal ions in the diatomite, so that the metal ions in the diatomite are prevented from falling off, and the performance of the cellulose derivative is reduced.
Further, the mass ratio of the diatomite, catecholamine and Tirs-HCl buffer solution is (1.1-1.3) g (0.1-0.3) g (45-55) mL.
Further, the dosage ratio of the flame retardant, the deionized water and the pretreated diatomite is (2-3) g (15-25) mL (0.5-1.5) g.
Further, the diatomite contains 70-90% of SiO 2, 0.6-8% of Al 2O3, 0.5-0.9% of MgO, 0.3-3% of CaO and 0.4-0.44g/cm 3 of density.
A2. the modified diatomite and the silica sol are mixed, stirred for 10min at 25 ℃, filtered, washed 3 times with deionized water, and dried in a 100 ℃ oven for 2h times, thus obtaining the composite filler.
The aldehyde group and aluminum ion contained on the surface of the diatomite deposited with the flame retardant can be combined with the silicon hydroxyl generated by hydrolysis of the silica sol through chemical bonds, so that the crosslinking density of the silica sol is increased, the mechanical property is improved, the diatomite deposited with the flame retardant is embedded into a silica sol system, the diatomite deposited with the flame retardant has excellent waterproof property, and the problem that the flame retardant is easy to absorb water and decompose, so that the flame retardant performance is reduced is avoided.
Further, the dosage ratio of the pretreated diatomite to the silica sol is (0.5-1.5) g (45-55) mL.
Further, the silica sol is prepared by the following steps:
Mixing ethanol, tetraethyl silicate and deionized water, placing in a 55-65 ℃ water bath kettle, stirring for 1-3 hours, cooling to room temperature, adding hydrochloric acid with the mass fraction of 36%, and continuously stirring for 24 hours to enable the ethyl silicate to undergo hydrolysis reaction under an acidic condition to obtain silica sol.
Further, the volume ratio of the ethanol to the tetraethyl silicate to the deionized water to the hydrochloric acid is (50-60): (40-50): (12-13): (1-2).
Further, the flame retardant is prepared by mixing and reacting tetrakis (hydroxymethyl) phosphonium sulfate, melamine, glutaraldehyde and aluminum sulfate, and is specifically prepared by the following steps:
Adding the tetrakis (hydroxymethyl) phosphonium sulfate into deionized water, uniformly stirring, adding melamine, stirring at 100 ℃ for reaction for 25min, cooling to room temperature, filtering to obtain filter residues, washing the filter residues with deionized water for 3 times to obtain a monomer, adding the monomer into a sodium hydroxide aqueous solution with the pH of 8, adding glutaraldehyde, reacting at 80 ℃ for 15min, adding aluminum sulfate, stirring for reaction for 20min, and freeze-drying in a freeze dryer at-20 ℃ for 1h to obtain the flame retardant.
The hydroxyl of the tetramethylolphosphate can be combined with the amino of melamine through positive and negative electricity, so that the tetramethylolphosphate is grafted on the melamine, the amino of the melamine in the intermediate can react with glutaraldehyde to form Schiff base as an intermediate raw material, further aldehyde groups are carried on the intermediate, the aldehyde groups are further combined with aluminum ions in aluminum sulfate to form a nitrogen-phosphorus-aluminum flame retardant, and the nitrogen-phosphorus-aluminum flame retardant is freeze-dried to form powder, so that the powder is filled into silica sol, contains rich N, P, al elements, has excellent flame retardant performance, and further can realize the flame retardant performance of cellulose derivatives.
Further, the dosage ratio of the phosphoric acid tetra-methylol sulfate, the deionized water and the melamine is (4-4.2) g (45-55) mL (3.5-3.9) g.
Further, the dosage ratio of the monomer, the sodium hydroxide aqueous solution, glutaraldehyde and aluminum sulfate is (5.1-5.3) g (25-35) mL (3.2-3.6) g.
Further, the modifier is prepared by reacting 4-ethynyl toluene with o-carborane, oxidizing by an oxidant, and then reacting with citric acid, and is specifically prepared by the following steps:
B1. Adding 4-ethynyl toluene and o-carborane into tetrahydrofuran, uniformly stirring, adding N, N-dimethylaniline, stirring for reaction for 30min, standing, taking out an organic phase, adding anhydrous magnesium sulfate into the organic phase to remove water participated in the organic phase, removing a solvent through a rotary evaporator to obtain a solid, adding the solid and an oxidant into ethanol, stirring, adding thionyl chloride for activation after the reaction is finished, filtering, washing with ethanol for 3 times, and drying in an oven at 85 ℃ for 10min to obtain carboxylated o-carborane.
The nucleophilic N, N-dimethylaniline is used as an activating agent, alkyne insertion reaction is carried out on alkynyl of 4-ethynyl toluene and o-carborane, so that 4-ethynyl toluene is grafted on the o-carborane monomer, further, under the action of an oxidant chromium trioxide, methyl of 4-ethynyl toluene grafted on the o-carborane monomer is oxidized into carboxyl, carboxylation o-carborane is realized, thionyl chloride is used as an activating agent, the carboxyl of the o-carborane can be activated, the carboxylation o-carborane contains a stable cage-shaped structure, has higher thermal resistance and thermal stability, the o-carborane is grafted on cellulose, the thermal stability of cellulose derivatives can be improved, and the cellulose derivatives are prevented from being decomposed by heating.
Further, the dosage ratio of 4-ethynyl toluene, o-carborane, tetrahydrofuran and N, N-dimethylaniline is (2-3) g (1-2) g (45-55) mL (0.3-0.7) g.
Further, the dosage ratio of the solid, the oxidant, the ethanol and the thionyl chloride is (2-3) g (0.1-0.3) g (25-35) mL (0.05-0.15) g
Further, the oxidizing agent is selected from chromium trioxide or chromium oxide.
B2. Adding carboxylated o-carborane and citric acid into ethanol, stirring at 1000rpm for 10min, adding 10mol/L sodium hydroxide aqueous solution to adjust pH to 2.5, stirring at 130 ℃ for reaction for 1.5h, filtering, washing with ethanol for 3 times to remove unreacted citric acid, and drying in an 80 ℃ oven for 10min to obtain the modifier.
The carboxyl of the carboxylated ortho-carborane can be subjected to esterification reaction with the hydroxyl of citric acid, so that the citric acid is grafted on the carboxylated ortho-carborane, the citric acid can participate in the esterification reaction of crop straw-based cellulose to form a cellulose derivative, and after the citric acid is subjected to esterification modification, the crystallinity of the crop straw-based cellulose can be reduced, the activity and degradation performance of the cellulose derivative are improved, and in addition, the introduction of the high-thermal-stability ortho-carborane is avoided, and the influence on the thermal stability of the cellulose due to the reduction of the crystallinity of the cellulose is avoided.
Further, the dosage ratio of carboxylated o-carborane, citric acid, ethanol and sodium hydroxide aqueous solution is (1.1-1.3) g (8-12) g (25-35) mL (0.1-0.3) mL.
Further, compared with the prior art, the invention has the following beneficial effects:
(1) According to the technical scheme, the tetramethylolphosphate, the melamine, the glutaraldehyde and the aluminum sulfate are mixed to react to form the nitrogen-phosphorus-aluminum flame retardant, the flame retardant contains rich N, P, al elements, has excellent flame retardant property and further can be used for resisting the flame of cellulose derivatives, the flame retardant is ground into powder, catecholamine is deposited on the surface of diatomite, on one hand, the diatomite is used as a carrier of the flame retardant to be compounded with the diatomite, the flame retardant property is improved, and the diatomite is used as an inorganic material, so that the mechanical strength of the cellulose derivatives can be improved, on the other hand, the flame retardant powder can be used for filling or plugging the porous structure of the diatomite, hydroxyl groups contained in the flame retardant can be used for fixing metal ions in the diatomite, and the falling of the metal ions in the diatomite can be avoided, so that the cellulose derivatives are prevented from being degraded.
(2) In the technical scheme of the invention, aldehyde groups and aluminum ions contained on the surface of the modified diatomite can be combined with silicon hydroxyl generated by hydrolysis of the silica sol through chemical bonds, so that the modified diatomite is embedded into a silica sol system, the crosslinking density of the silica sol is increased, the mechanical property is improved, and the modified diatomite is embedded into the silica sol system, so that the modified diatomite has excellent waterproof property and is prevented from being decomposed by water absorption easily, and the flame retardant property is prevented from being reduced.
(3) According to the technical scheme, the carboxylated o-carborane contains a stable cage-shaped structure, has higher thermal resistance and thermal stability, the carboxylated o-carborane is grafted on cellulose, the thermal stability of cellulose derivatives can be improved, the cellulose derivatives are prevented from being heated and decomposed, the carboxyl of the carboxylated o-carborane can be subjected to esterification reaction with the hydroxyl of citric acid, and the citric acid can participate in the esterification reaction of crop straw-based cellulose, so that the carboxylated o-carborane is easier to graft on the crop straw-based cellulose to form the cellulose derivatives, the cellulose derivatives have higher thermal stability, after the cellulose is modified by citric acid esterification, the crystallinity of the crop straw-based cellulose can be reduced, the activity and the degradation performance of the cellulose derivatives are improved, the binding force with composite filler is increased, and in addition, the introduction of the high-thermal-stability o-carborane is avoided, and the thermal stability of the cellulose is prevented from being influenced by the reduction of the crystallinity of the cellulose.
(4) According to the technical scheme, the crop straw is crushed and puffed, so that a waxy film and a cell wall on the surface of the crop straw are broken, hemicellulose covered on cellulose is separated from a lignin structure, further extraction and separation of cellulose in the crop straw are facilitated, air in the crop straw is discharged under the action of high temperature, high pressure and high shearing force in an extrusion cavity, the cell wall and the cell membrane structure of the crop straw are damaged, the surface of the crop straw is provided with a porous structure, and the contact area with a treating agent is increased.
(5) In the technical scheme of the invention, sodium carbonate and calcium oxide in the treating agent have the characteristics of high safety, low corrosiveness and low cost, are used for replacing the conventional sodium hydroxide to treat straws, reduce the generation of waste liquid, combine the sodium carbonate and the calcium oxide to treat, can improve the concentration of hydroxyl in the pretreatment agent through double decomposition reaction, can effectively remove lignin and hemicellulose in crop straws, and the porous structure generated by puffing the crop straws increases the contact area with the pretreatment agent, so that the extraction rate of cellulose is increased.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The raw materials used in the examples of the present invention were tetraethyl silicate (chemical purity, ara Ding Shiji), methacryloyl chloride (purity 95%, michelin reagent Co., ltd.), tetrakis (hydroxymethyl) phosphonium sulfate (analytical purity, shanghai Michelin Biochemical Co., ltd.), aluminum sulfate, glutaraldehyde, melamine (analytical purity, chemie Kelong chemical reagent Co., ltd.), catecholamine (purity 98%, ara Ding Shiji), tirs-HCl (content 99%, ara Ding Shiji), 4-ethynyl toluene (purity 98%, guangzhou and medical technologies Co., ltd.), o-carborane (purity 99%, hubei Xin Yu March biomedical technologies Co., ltd.), chromium trioxide (purity 99%, shandong Ji Jida chemical Co., ltd.), calcium oxide (Shandong Seisaku chemical Co., ltd.), sodium carbonate (Industrial grade), citric acid (analytical purity, country Co., ltd.).
The diatomite contains 70-90% of SiO 2, 0.6-8% of Al 2O3, 0.5-0.9% of MgO, 0.3-3% of CaO and 0.4-0.44g/cm 3 of density, and reaches chemical industry Co., ltd.
The silica sol is prepared by the following steps:
Mixing 56mL of ethanol, 44mL of tetraethyl silicate and 12.4mL of deionized water, placing in a water bath at 60 ℃, stirring for 2h, cooling to room temperature, adding 1.6mL of hydrochloric acid with the mass fraction of 36%, and continuing stirring for 24h to enable the ethyl silicate to undergo hydrolysis reaction under an acidic condition to obtain silica sol.
Example 1
The composite filler is prepared by the following steps:
A1. Adding 4.1g of tetrakis (hydroxymethyl) phosphonium sulfate into 50mL of deionized water, uniformly stirring, adding 3.7g of melamine, stirring and reacting for 25min at 100 ℃, cooling to room temperature, filtering to obtain filter residues, washing the filter residues with deionized water for 3 times to obtain a monomer, adding 5.2g of the monomer into 30mL of sodium hydroxide aqueous solution with pH of 8, adding 1.2g of glutaraldehyde, reacting for 15min at 80 ℃, adding 3.4g of aluminum sulfate, stirring and reacting for 20min, and freeze-drying for 1h in a freeze dryer at-20 ℃ to obtain the flame retardant.
A2. Adding 1.2g of kieselguhr and 0.2g of catecholamine into 50mL of Tirs-HCl buffer solution with pH of 8.5, stirring for reaction for 24 hours, filtering, washing 3 times with ethanol, washing 3 times with deionized water, drying in a 60 ℃ oven for 10 minutes to obtain pretreated kieselguhr, grinding 2.6g of flame retardant into powder, adding into 20mL of deionized water, stirring uniformly, adding 1g of pretreated kieselguhr, stirring at 45 ℃ for 30 minutes, cooling to room temperature, filtering, washing 3 times with deionized water, and drying in a 70 ℃ oven for 8 minutes to obtain the modified kieselguhr.
A3. 1g of pretreated diatomaceous earth and 50mL of silica sol were mixed, stirred at 25℃for 10min, filtered, washed 3 times with deionized water, and dried in a100℃oven for 2 h to give a composite filler.
Comparative example 1
This comparative example differs from example 1 in that the modified diatomaceous earth was replaced with a flame retardant, and the rest of the procedure and raw materials were synchronized with example 1.
A1. Adding 4.1g of tetrakis (hydroxymethyl) phosphonium sulfate into 50mL of deionized water, uniformly stirring, adding 3.7g of melamine, stirring and reacting for 25min at 100 ℃, cooling to room temperature, filtering to obtain filter residues, washing the filter residues with deionized water for 3 times to obtain a monomer, adding 5.2g of the monomer into 30mL of sodium hydroxide aqueous solution with pH of 8, adding 1.2g of glutaraldehyde, reacting for 15min at 80 ℃, adding 3.4g of aluminum sulfate, stirring and reacting for 20min, and freeze-drying for 1h in a freeze dryer at-20 ℃ to obtain the flame retardant.
A2. 1g of flame retardant and 50mL of silica sol were mixed, stirred at 25℃for 10min, filtered, washed 3 times with deionized water, and dried in a 100℃oven for 2h to give a composite filler.
Comparative example 2
This comparative example differs from example 1 in that no silica sol was added, and the rest of the procedure and starting materials were synchronized with example 1.
A1. Adding 4.1g of tetrakis (hydroxymethyl) phosphonium sulfate into 50mL of deionized water, uniformly stirring, adding 3.7g of melamine, stirring and reacting for 25min at 100 ℃, cooling to room temperature, filtering to obtain filter residues, washing the filter residues with deionized water for 3 times to obtain a monomer, adding 5.2g of the monomer into 30mL of sodium hydroxide aqueous solution with pH of 8, adding 1.2g of glutaraldehyde, reacting for 15min at 80 ℃, adding 3.4g of aluminum sulfate, stirring and reacting for 20min, and freeze-drying for 1h in a freeze dryer at-20 ℃ to obtain the flame retardant.
A2. Adding 1.2g of kieselguhr and 0.2g of catecholamine into 50mL of Tirs-HCl buffer solution with pH of 8.5, stirring for reaction for 24 hours, filtering, washing 3 times with ethanol, washing 3 times with deionized water, drying in a60 ℃ oven for 10 minutes to obtain pretreated kieselguhr, grinding 2.6g of flame retardant into powder, adding into 20mL of deionized water, stirring uniformly, adding 1g of pretreated kieselguhr, stirring at 45 ℃ for 30 minutes, cooling to room temperature, filtering, washing 3 times with deionized water, and drying in a 70 ℃ oven for 8 minutes to obtain the composite filler.
Example 2
The modifier is prepared by the following steps:
B1. Adding 2.5g of 4-ethynyl toluene and 1.5g of o-carborane into 50mL of tetrahydrofuran, uniformly stirring, adding 0.5g of N, N-dimethylaniline, stirring for reaction for 30min, standing, taking out an organic phase, adding anhydrous magnesium sulfate into the organic phase to remove water participated in the organic phase, removing a solvent through a rotary evaporator to obtain a solid, adding 2.5g of the solid and 0.2g of chromium trioxide into 30mL of ethanol, stirring, adding 0.1g of thionyl chloride for activation after the reaction, filtering, washing 3 times through ethanol, and drying in an oven at 85 ℃ for 10min to obtain carboxylated o-carborane.
B2. 1.2g of carboxylated ortho-carborane and 10g of citric acid are added into 30mL of ethanol, stirred at the speed of 1000rpm for 10min, 0.2mL of 10mol/L sodium hydroxide aqueous solution is added to adjust the pH to 2.5, stirred at 130 ℃ for 1.5h, filtered, washed with ethanol for 3 times to remove unreacted citric acid, and dried in an 80 ℃ oven for 10min to obtain the modifier.
Comparative example 3
This comparative example differs from example 2 in that no citric acid was added and the rest of the procedure synchronized with example 2.
Adding 2.5g of 4-ethynyl toluene and 1.5g of o-carborane into 50mL of tetrahydrofuran, uniformly stirring, adding 0.5g of N, N-dimethylaniline, stirring for reaction for 30min, standing, taking out an organic phase, adding anhydrous magnesium sulfate into the organic phase to remove water participated in the organic phase, removing a solvent through a rotary evaporator to obtain a solid, adding 2.5g of the solid and 0.2g of chromium trioxide into 30mL of ethanol, stirring, adding 0.1g of thionyl chloride for activation after the reaction, filtering, washing 3 times through ethanol, and drying in an oven at 85 ℃ for 10min to obtain carboxylated o-carborane.
Example 3
A method for preparing cellulose derivatives by using crop straws as raw materials comprises the following steps:
s1, crushing crop straws in a crusher, processing the crushed crop straws in a double-screw extrusion bulking machine, and drying the crushed crop straws at 18 ℃ for 15min to obtain crop straw raw materials, wherein the temperature of the double-screw extrusion machine is 125 ℃, the rotating speed of the screw is 145/min, the flow rate of deionized water is 510g/h, and the feeding speed is 610g/h.
S2, adding 4g of crop straw raw materials into 70mL of treating agent, stirring and reacting for 2h, standing for 1h, adjusting pH to be neutral by using 1mL of hydrochloric acid with mass fraction of 36%, filtering, washing for 3 times by using deionized water, and drying in a 65 ℃ oven for 10min to obtain crop straw base cellulose, wherein the treating agent is prepared by mixing calcium oxide, sodium carbonate and deionized water according to the dosage ratio of 1g to 2.3g to 70 mL.
S3, adding 0.1g of crop straw-based cellulose into 8mL of deionized water, uniformly stirring, adding 0.3mL of 60% sodium hydroxide aqueous solution, alkalizing at 35 ℃ for 0.7h, filtering, and washing to obtain the alkalized crop straw-based cellulose.
S4, adding 60g of alkalized crop straw-based cellulose into 400mL of deionized water, uniformly stirring, adding 45g of modifier, stirring for 30min, drying at 80 ℃ for 12h, heating to 130 ℃, reacting for 4h, adding 1g of composite filler, stirring for 10min, washing 3 times by deionized water, and drying in a 50 ℃ oven for 12h to obtain the cellulose derivative.
Example 4
A method for preparing cellulose derivatives by using crop straws as raw materials comprises the following steps:
s1, crushing crop straws in a crusher, processing the crushed crop straws in a double-screw extrusion bulking machine, and drying the crushed crop straws at 18 ℃ for 15min to obtain crop straw raw materials, wherein the temperature of the double-screw extrusion machine is 125 ℃, the rotating speed of the screw is 145/min, the flow rate of deionized water is 510g/h, and the feeding speed is 610g/h.
S2, adding 5g of crop straw raw materials into 75mL of treating agent, stirring and reacting for 2h, standing for 1h, adjusting pH to be neutral by using hydrochloric acid with the mass fraction of 36% of 2mL, filtering, washing for 3 times by using deionized water, and drying in a 65 ℃ oven for 10min to obtain crop straw base cellulose, wherein the treating agent is prepared by mixing calcium oxide, sodium carbonate and deionized water according to the dosage ratio of 1g:2.3g:70 mL.
S3, adding 0.2g of crop straw-based cellulose into 10mL of deionized water, uniformly stirring, adding 0.5mL of 60% sodium hydroxide aqueous solution, alkalizing at 40 ℃ for 0.5-1h, filtering, and washing to obtain alkalized crop straw-based cellulose.
S4, adding 70g of alkalized crop straw-based cellulose into 500mL of deionized water, uniformly stirring, adding 50g of modifier, stirring for 30min, drying at 80 ℃ for 12h, heating to 130 ℃, reacting for 4h, adding 2g of composite filler, stirring for 10min, washing 3 times by deionized water, and drying in a 50 ℃ oven for 12h to obtain the cellulose derivative.
Example 5
A method for preparing cellulose derivatives by using crop straws as raw materials comprises the following steps:
s1, crushing crop straws in a crusher, processing the crushed crop straws in a double-screw extrusion bulking machine, and drying the crushed crop straws at 18 ℃ for 15min to obtain crop straw raw materials, wherein the temperature of the double-screw extrusion machine is 125 ℃, the rotating speed of the screw is 145/min, the flow rate of deionized water is 510g/h, and the feeding speed is 610g/h.
S2, adding 6g of crop straw raw materials into 80mL of treating agent, stirring and reacting for 2h, standing for 1h, regulating pH to be neutral by using 3mL of hydrochloric acid with mass fraction of 36%, filtering, washing for 3 times by using deionized water, and drying in a 65 ℃ oven for 10min to obtain crop straw base cellulose, wherein the treating agent is prepared by mixing calcium oxide, sodium carbonate and deionized water according to the dosage ratio of 1g to 2.3g to 70 mL.
S3, adding 0.3g of crop straw-based cellulose into 12mL of deionized water, uniformly stirring, adding 0.7mL of 60% sodium hydroxide aqueous solution, alkalizing at 35 ℃ for 0.7h, filtering, and washing to obtain the alkalized crop straw-based cellulose.
S4, adding 80g of alkalized crop straw-based cellulose into 600mL of deionized water, uniformly stirring, adding 55g of modifier, stirring for 30min, drying at 80 ℃ for 12h, heating to 130 ℃, reacting for 4h, adding 3g of composite filler, stirring for 10min, washing 3 times by deionized water, and drying in a 50 ℃ oven for 12h to obtain the cellulose derivative.
Comparative example 4
This comparative example differs from example 4 in that the composite filler was replaced with the material prepared in comparative example 1, and the rest of the procedure was synchronized with example 4.
Comparative example 5
This comparative example differs from example 4 in that the composite filler was replaced with the material prepared in comparative example 2, and the rest of the procedure was synchronized with example 4.
Comparative example 6
This comparative example differs from example 4 in that the modifier is replaced by the material prepared in comparative example 3, the rest of the procedure being synchronized with example 4.
Comparative example 7
This comparative example differs from example 4 in that the treating agent was replaced with sodium hydroxide and the rest of the procedure was synchronized with example 4 without puffing.
The cellulose derivatives prepared in examples 3 to 5 and comparative examples 4 to 7 were now subjected to performance tests;
The crop straw selected by the invention has the cellulose accounting for 30-40%, the hemicellulose accounting for 20-30 and the lignin accounting for 10-20%.
Lignin and hemicellulose removal rates were measured according to steps S1 and S2 in example 4, and were measured by national standards GB/T20806-2006, van Soest measurement and GB/T20805-2006 (index conversion formula: Z (%) = (x1×y1)/(x2×y2) ×100%, where Z represents lignin/hemicellulose removal rate, X1 represents lignin/hemicellulose content in the treated straw, X2 represents lignin/hemicellulose content in the straw before treatment, Y1 represents dry matter mass of the straw after treatment, and Y2 represents dry matter mass of the straw before treatment).
The heat stability of the above-mentioned prepared cellulose derivative was measured by a thermogravimetric analyzer by taking the weight of the above-mentioned prepared cellulose derivative about 5g, the temperature rising rate of 10℃per minute, the nitrogen atmosphere, the flow rate of 20mL per minute, and the temperature range of 300 to 500℃and measuring the decomposition temperature (°C) of the cellulose derivative.
The flame retardant properties of the above-prepared cellulose derivatives were measured by the vertical combustion test using a CZF-3 type horizontal vertical combustion tester, by referring to GB/2409-84 method.
A film with a thickness of 300 μm was prepared by hot pressing with a press vulcanizer (BL-6170-B, dongguan medical treasured precision detection instruments Co., ltd., china) at 160℃under 10MPa for a duration of 5min for detecting the mechanical properties of the cellulose derivative.
The films were tested for tensile strength and elongation at break at room temperature using a universal materials testing machine (5967,INSTRON,United States). During testing, the stretching rate was 2mm/min and the clamp spacing was 20mm. The test results are shown in table 1 below.
TABLE 1 test results
As can be seen from the test results of table 1, the comparative example 4, in which the modified diatomaceous earth was replaced with the composite filler prepared by the flame retardant, was added to the cellulose derivative, and its flame retardant property and mechanical property were lowered, probably because the diatomaceous earth was compounded with the diatomaceous earth as a carrier of the flame retardant, the flame retardant property was improved, and the diatomaceous earth as an inorganic material, the mechanical strength of the cellulose derivative was improved; the composite filler prepared without adding silica sol in comparative example 5 was added to cellulose derivative, which may be because the modified diatomaceous earth was embedded in silica sol system, which has excellent waterproof property, prevents the fire retardant from being decomposed by water absorption, and the fire retardant powder could fill or block the porous structure of diatomaceous earth, prevents the metal ion in diatomaceous earth from falling off, and thus the cellulose derivative from decreasing in performance, the cellulose derivative prepared without adding citric acid in comparative example 6 had even decreased thermal stability, mechanical property and fire retardant property, which may be because citric acid could participate in esterification reaction of crop straw-based cellulose, so that carboxylated o-carborane could be grafted on crop straw-based cellulose more easily, which has higher thermal stability, and improves activity of cellulose derivative, and increases binding force with composite filler, the treatment agent was replaced with sodium hydroxide, and without puffing treatment, lignin and hemicellulose removal rate in crop straw could be decreased, which may be because sodium carbonate and calcium oxide treatment could be combined with pretreatment to improve concentration of lignin and hemicellulose in crop straw-based cellulose, and the porous structure generated by puffing the crop straw increases the contact area with the pretreatment agent, and increases the extraction rate of cellulose.
Table 1 data illustrates a method for preparing cellulose derivatives from crop straws in examples 3-5, crushing and puffing the crop straws to obtain crop straw raw materials, treating the crop straw raw materials with a treating agent to obtain crop straw base cellulose, alkalizing the crop straw base cellulose, mixing the crop straw base cellulose with a modifying agent and a composite filler to obtain the cellulose derivatives which meet the requirement of testing performance, and the cellulose derivatives prepared in comparative examples 4-7 do not meet the standard of performance requirement, so that the cellulose derivatives prepared in the invention have better mechanical performance, flame retardant performance and thermal stability, and have higher cellulose extraction rate in the crop straws.
In the description of the present specification, the descriptions of the terms "one embodiment," "example," "specific example," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing is merely illustrative and explanatory of the invention, as various modifications and additions may be made to the particular embodiments described, or in a similar manner, by those skilled in the art, without departing from the scope of the invention or exceeding the scope of the invention as defined in the claims.
Claims (10)
1. The method for preparing the cellulose derivative by taking the crop straw as the raw material is characterized by comprising the following steps of:
s1, crushing and puffing crop straws to obtain crop straw raw materials;
S2, treating the crop straw raw material by a treating agent to obtain crop straw base cellulose;
S3, after alkalizing the crop straw base cellulose, mixing the crop straw base cellulose with a modifier and a composite filler to obtain a cellulose derivative;
the composite filler is prepared by depositing a flame retardant on the surface of diatomite and then mixing with silica sol, and is specifically prepared by the following steps:
A1. Adding diatomite and catecholamine into Tirs-HCl buffer solution with pH of 8.5, stirring and reacting for 24 hours, filtering, washing with ethanol for 3 times, washing with deionized water for 3 times, drying in a 60 ℃ oven for 10min to obtain pretreated diatomite, grinding a flame retardant into powder, adding into deionized water, uniformly stirring, adding pretreated diatomite, stirring for 30min at 45 ℃, cooling to room temperature, filtering, washing with deionized water for 3 times, and drying in a 70 ℃ oven for 8min to obtain modified diatomite;
A2. mixing the modified diatomite and the silica sol, stirring for 10min at 25 ℃, filtering, washing with deionized water for 3 times, and drying for 2h times in a 100 ℃ oven to obtain a composite filler;
the flame retardant is prepared by mixing and reacting tetrakis (hydroxymethyl) phosphonium sulfate, melamine, glutaraldehyde and aluminum sulfate;
the modifier is prepared by reacting 4-ethynyl toluene with o-carborane, oxidizing by an oxidant and then reacting with citric acid, and comprises the following specific steps:
B1. Adding 4-ethynyl toluene and o-carborane into tetrahydrofuran, uniformly stirring, adding N, N-dimethylaniline, stirring and reacting for 30min, standing, taking out an organic phase, adding anhydrous magnesium sulfate into the organic phase to remove water participated in the organic phase, removing a solvent through a rotary evaporator to obtain a solid, adding the solid and an oxidant into ethanol, stirring, adding thionyl chloride for activation after the reaction is finished, filtering, washing with ethanol for 3 times, and drying in an oven at 85 ℃ for 10min to obtain carboxylated o-carborane;
B2. Adding carboxylated o-carborane and citric acid into ethanol, stirring at 1000rpm for 10min, adding 10mol/L sodium hydroxide aqueous solution to adjust pH to 2.5, stirring at 130 ℃ for reaction for 1.5h, filtering, washing with ethanol for 3 times to remove unreacted citric acid, and drying in an 80 ℃ oven for 10min to obtain the modifier.
2. The method for preparing the cellulose derivative by using the crop straw as the raw material according to claim 1, wherein the specific steps of crushing and puffing the crop straw are that the crop straw is crushed in a crusher and then is dried for 10-20min at 45-50 ℃ after being processed in a double screw extrusion puffing machine, so as to obtain the crop straw raw material.
3. The method for preparing cellulose derivatives from crop straws as set forth in claim 2, wherein the twin-screw extruder is at a temperature of 120-130 ℃, a screw speed of 140-150r/min, a deionized water flow rate of 500-520g/h, and a feed rate of 600-620g/h.
4. The method for preparing cellulose derivatives by using crop straws as raw materials according to claim 1, wherein the treating agent is prepared by mixing calcium oxide, sodium carbonate and deionized water according to the dosage ratio of (0.5-1.5) g (2.2-2.4) g (60-80) mL.
5. The method for preparing cellulose derivatives by using crop straws as raw materials according to claim 1, wherein the alkalization treatment specifically comprises the steps of adding crop straw-based cellulose into deionized water, uniformly stirring, adding 55-65% sodium hydroxide aqueous solution by mass fraction, alkalizing at 30-40 ℃ for 0.5-1h, filtering, and washing to obtain alkalized crop straw-based cellulose.
6. The method for preparing cellulose derivatives from crop stalks as claimed in claim 1, wherein the oxidizing agent is selected from chromium trioxide and chromium oxide.
7. The method for preparing cellulose derivatives from crop straws according to claim 1, wherein the silica sol is prepared by the following steps:
Mixing ethanol, tetraethyl silicate and deionized water, placing in a 55-65 ℃ water bath kettle, stirring for 1-3h, cooling to room temperature, adding 30-40% hydrochloric acid by mass fraction, and continuing stirring for 24h to obtain silica sol.
8. The method for preparing cellulose derivatives from crop straws as set forth in claim 7, wherein the volume ratio of ethanol, tetraethyl silicate, deionized water and hydrochloric acid is (50-60): (40-50): (12-13): (1-2).
9. The method for preparing cellulose derivatives from crop straws according to claim 1, wherein the diatomite has a content of SiO 2 of 70-90%, a content of Al 2O3 of 0.6% -8%, a content of MgO of 0.5-0.9%, a content of CaO of 0.3-3% and a density of 0.4-0.44g/cm 3.
10. The method for preparing the cellulose derivative by taking the crop straw as the raw material, which is disclosed in claim 1, wherein the mass ratio of the alkalized crop straw-based cellulose to the modifier to the composite filler is (60-80): 45-55): 1-3.
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| CN101186677A (en) * | 2007-12-20 | 2008-05-28 | 江南大学 | Method for preparing cellulose polysaccharide degradable superabsorbent from crop straw |
| CN101235604A (en) * | 2007-01-31 | 2008-08-06 | 中国科学院化学研究所 | Method for extracting cellulose from straw |
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| CN101029459A (en) * | 2006-02-27 | 2007-09-05 | 江苏绿陵生态肥有限公司 | Technology for producing ligin by crop straw refuse |
| CN106590806A (en) * | 2016-11-22 | 2017-04-26 | 汪逸凡 | Method for preparing high-efficiency stable coal combustion improver |
| CN108660836A (en) * | 2018-05-18 | 2018-10-16 | 通化县兴隆中药材专业合作社 | A method of extracting cellulose using stalk |
| JP2021025003A (en) * | 2019-08-08 | 2021-02-22 | 日本製紙株式会社 | Flame-retardant composite fiber and method for producing the same |
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