CN114956772B

CN114956772B - 3D printing heat-preservation cementing material containing modified wood powder and preparation method and application thereof

Info

Publication number: CN114956772B
Application number: CN202210685438.2A
Authority: CN
Inventors: 陈明旭; 李秋义; 王亮; 岳公冰; 郭远新
Original assignee: Qingdao Agricultural University
Current assignee: Qingdao Agricultural University
Priority date: 2022-06-15
Filing date: 2022-06-15
Publication date: 2023-02-03
Anticipated expiration: 2042-06-15
Also published as: CN114956772A

Abstract

The invention discloses a 3D printing heat-preservation cementing material containing modified wood powder and a preparation method and application thereof. The cementing material comprises the following components in parts by weight: 70-100 parts of magnesium phosphate composite material, 5-15 parts of mineral admixture, 5-20 parts of modified wood powder, 1.2-5.6 parts of auxiliary agent and 15-20 parts of water. The preparation of the modified wood flour comprises the following steps: (1) And placing the wood powder in water, sequentially adding acetic anhydride and maleic anhydride, removing the wood powder after the reaction is finished, washing and drying to obtain the modified wood powder precursor. (2) And (2) placing the modified wood flour precursor in water, then sequentially adding a silane coupling agent and nitric acid, continuously adding ammonium ceric nitrate and a vinyl monomer after reaction, washing the modified wood flour precursor after the reaction is finished, and drying to obtain the modified wood flour. The 3D printing cementing material disclosed by the invention can effectively utilize the waste wood powder to improve the thixotropy of the 3D printing cementing material, so that the structure of a 3D printing product is stabilized.

Description

3D printing heat-preservation cementing material containing modified wood powder and preparation method and application thereof

Technical Field

The invention relates to the technical field of 3D printing materials, in particular to a 3D printing heat-preservation cementing material containing modified wood powder and a preparation method and application thereof.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

As a new green preparation technology in the field of civil engineering, the 3D printing technology has the technical problem that the stability of printing slurry and the structural stability of printed products are difficult to regulate and control. In contrast to conventional manufacturing methods, 3D printing techniques accomplish printing of objects through extrusion systems without the aid of a stencil. However, for building materials, this forming method requires that the printed material have controllable printability, including flow, extrudability, constructability, and construction time, in order to accurately build the 3D structure.

For the printability of cement-based composites, current research is mainly focused on the rheological properties of the slurry, in order to expect a stable 3D printed structure. The stacking properties of 3D printing pastes mainly benefit from their good extrudability and constructability, which mainly depends on the regulation of yield stress, thixotropy and viscoelasticity. At present, most of researches on accurate establishment of a 3D printing structure adopt materials with high water absorption rate to simultaneously regulate and control rheological property and stability of printing slurry.

Disclosure of Invention

The invention provides a 3D printing heat-preservation cementing material containing modified wood powder and a preparation method and application thereof. To achieve the above object, the present invention specifically provides the following.

In a first aspect of the invention, the 3D printing heat-preservation cementing material containing modified wood flour comprises the following raw materials in parts by weight:

the modified wood flour can well regulate and control the thixotropic performance of the 3D printing binding material, so that the printing structure of the 3D printing binding material is improved, and meanwhile, the modified wood flour can also improve the strength of the 3D printing binding material and improve the durability. The preparation method of the modified wood powder comprises the following steps:

(1) And (3) placing the wood powder in water, then sequentially adding acetic anhydride and maleic anhydride, and drying after the reaction is finished to obtain the modified wood powder precursor.

(2) And (2) placing the modified wood flour precursor in water, then sequentially adding a silane coupling agent and nitric acid, continuously adding ammonium ceric nitrate and a vinyl monomer after reaction, washing the modified wood flour precursor after the reaction is finished, and drying to obtain the modified wood flour.

Further, in the step (1), the wood flour is prepared by using waste wood. Preferably, the preparation method comprises the steps of: grinding the waste wood, placing the obtained wood powder in water, stirring, standing, collecting the wood powder precipitated in the water, and drying to obtain the wood-plastic composite material. Preferably, the particle size of the wood powder is 0.1 to 200 μm.

Preferably, the method further comprises the steps of: placing the dried wood powder into absolute ethyl alcohol for magnetic separation to remove metal impurities; and after drying, drying the regenerated wood powder subjected to magnetic separation at 50-60 ℃ for 5-6 h, and then removing heavy impurities through air flow separation to obtain the wood powder.

Further, in the step (1), the mass ratio of the wood powder, the acetic anhydride, the maleic anhydride and the water is 1:10:10:100 to 200. The acetic anhydride and the maleic anhydride can reduce the number of hydroxyl in the wood powder, so that the water absorption of the wood powder is reduced, and the working performance of the printing paste containing the wood powder is flexibly regulated and controlled.

Further, in the step (1), the reaction temperature is 40-80 ℃ and the time is 10-40 min.

Further, in the step (1), the drying temperature is 80-105 ℃, and the drying time is 2-4 h.

Further, in the step (2), the mass ratio of the modified wood flour precursor to the silane coupling agent to water is 1:10:100 to 200. The silane coupling agent can connect organic matters and inorganic matters in the reaction process, and is easier for surface modification of wood flour.

Further, in the step (2), the nitric acid is added in an amount such that the concentration of the nitric acid in the reaction system is 0.01 to 0.05mol/L.

Further, in the step (2), the cerium ammonium nitrate is added in such an amount that the concentration of the cerium ammonium nitrate in the reaction system is 0.001 to 0.003mol/L. Ammonium ceric nitrate is used as an initiator to initiate the polymerization reaction of acrylic acid and acrylamide.

Further, in the step (2), the mass ratio of the modified wood flour precursor to the vinyl monomer is 5:1 to 2. Alternatively, the vinyl monomer comprises any one or two of butyl acrylate, hydroxybutyl vinyl ether, isobutyl vinyl ether, and the like.

Further, in the step (2), after reacting for 20-30 min, adding ammonium ceric nitrate and vinyl monomer, reacting for 15-25 min, and then adding hydroquinone to terminate the reaction.

Further, in the step (2), washing the modified wood flour precursor by any one of detergents such as ethanol and methanol; the drying temperature is 70-80 ℃ and the drying time is 3-4 h.

Further, the raw material of the 3D printing heat-preservation cementing material containing modified wood flour also comprises 0.5-5 parts by weight of modified polyphenyl particles. The modified polyphenyl particles are as follows: the polystyrene foam particle is prepared by soaking polystyrene particles (expanded polystyrene foam particles) in a mixed solution of a silane coupling agent and hydroxypropyl methyl cellulose.

Further, the mass ratio of the polyphenyl particles, the silane coupling agent and the hydroxypropyl methyl cellulose ether is 10:1:1 to 2. Optionally, the soaking time is 30-50 min. In the invention, the silane coupling agent and the hydroxypropyl methyl cellulose ether are used for modifying the performance of the polyphenyl particles, so that the bonding performance between the 3D printing cementing material and the polyphenyl particles can be well improved, and the mechanical property of printing slurry is improved. Meanwhile, the quality and the heat conductivity coefficient of a product obtained by 3D printing of the gelled material can be obviously reduced by doping the modified polyphenyl particles.

Further, the auxiliary agent comprises at least one of a thickening agent, a retarder and a water reducing agent. Preferably, the auxiliary agent comprises a thickening agent, a retarder and a water reducing agent according to the weight ratio of 1-5: 0.1-0.2 parts by weight: 0.1-0.4 weight portions.

Further, the magnesium phosphate composite material includes: dead burned magnesia, potassium dihydrogen phosphate, borax and silicate cement. Preferably, the mass ratio of the dead-burned magnesium oxide to the monopotassium phosphate is 7:1 to 3 percent, wherein the borax doping amount is 6 to 10 percent of the total mass of the magnesium oxide and the potassium dihydrogen phosphate; the mixing amount of the portland cement is 10-30% of the total mass of the magnesium oxide, the potassium dihydrogen phosphate and the borax. In the invention, a large amount of heat is released in the hydration process of the adopted magnesium phosphate composite material, and the reaction speed of the system can be further accelerated, so that the early mechanical property and the setting time of the 3D printing cementing material can be flexibly regulated and controlled, and the cohesiveness and the continuity of the slurry are improved.

Further, the mineral admixture is composed of quartz sand, slag micro powder and fly ash. Preferably, the mass ratio of the quartz sand to the slag micro powder to the fly ash is 2:1:1 to 2. The granularity of the quartz sand is 50-200 mu m, the granularity of the slag micro powder is 5-100 mu m, and the granularity of the fly ash is 0.1-50 mu m. According to the invention, the mineral admixture is doped, so that the stability of the 3D printing cementing material in the printing process can be improved, the viscosity of printing slurry is reduced, the phenomenon of extrusion opening blockage is avoided, and the printing structure stability is improved.

Further, the thickening agent is a composite thickening agent consisting of silica fume and hydroxypropyl methyl cellulose ether. Preferably, the mass ratio of the silica fume to the hydroxypropyl methyl cellulose ether is 10:1 to 3. According to the invention, the composite thickening agent can effectively improve the consistency of the 3D printing cementing material, prevent slurry segregation and bleeding in the printing process and stabilize the 3D printing structure.

Further, the water reducing agent comprises: a polycarboxylic acid-based water reducing agent, a naphthalene-based high-efficiency water reducing agent, and the like.

Further, the retarder includes: one or two of triethanolamine, polyvinyl alcohol and sodium chloride.

In a second aspect of the present invention, there is provided a preparation method of the 3D printing thermal insulation cementitious material containing modified wood flour, comprising the following steps:

(i) And uniformly mixing the magnesium phosphate composite material, the mineral admixture and the modified wood powder to obtain a solid mixture.

(ii) And dissolving the auxiliary agent in the water, and uniformly stirring to obtain a liquid mixture.

(iii) And adding the solid mixture into the liquid mixture, and uniformly mixing to obtain the 3D printing heat-preservation cementing material containing the modified wood powder.

Further, the solid mixture also comprises the modified polyphenyl particles.

In a third aspect of the invention, the 3D printed thermal insulation cementitious material containing modified wood flour is disclosed for use in the field of construction engineering, e.g., for 3D printed decorative members, specialty structural members, etc.

Compared with the prior art, the technical scheme provided by the invention at least has the following beneficial effects:

(1) The modified wood powder adopted by the invention can obviously improve the thixotropy of the 3D printing binding material and obviously improve the structural stability of a printed product. The reason for this is that: the vinyl monomer grafted on the surface of the modified wood flour can modify molecular groups on the surface of the wood flour, so that the dispersibility of the wood flour in the cement-based slurry is improved, meanwhile, the surface of the modified wood flour has hydrophilic surface groups, so that a large amount of free water in the printing slurry can be absorbed, and the free water can be released after the modified wood flour is subjected to shearing force, so that the thixotropy of the printing slurry is improved. Meanwhile, the density of the modified wood powder is far less than that of the cement-based material, and the density of the printing material can be obviously reduced when the modified wood powder is doped into the cementing material.

(2) According to the invention, the polyphenyl particles are modified by using the silane coupling agent and the hydroxypropyl methyl cellulose ether, so that organic and inorganic materials are connected, the bonding property between the 3D printing cementing material and the polyphenyl particles can be well improved, and the mechanical property of printing slurry is improved. Meanwhile, the heat conductivity coefficient and the density of the modified polyphenyl particles are both greatly reduced, the density and the heat conductivity coefficient of a product obtained by 3D printing of the binding material can be obviously reduced after the modified polyphenyl particles are doped, and the heat insulation performance of the material is improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are included to illustrate an exemplary embodiment of the invention and not to limit the invention. Embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:

fig. 1 is a graph showing the effect of the following first embodiment of 3D printed cement.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out according to conventional conditions or according to conditions recommended by the manufacturers.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The reagents or starting materials used in the present invention can be purchased from conventional sources, and unless otherwise specified, the reagents or starting materials used in the present invention can be used in a conventional manner in the art or in accordance with the product specification. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present invention. The preferred methods and materials described in this invention are exemplary only.

First embodiment

1. The embodiment of the invention provides a preparation method of modified wood flour, which is characterized in that waste wood is prepared into modified wood flour through a regeneration process so as to achieve the purposes of waste wood resource utilization and high-value utilization, and the preparation method specifically comprises the following steps:

(1) Preparing regenerated wood powder: the construction waste wood is ground by a grinder to prepare regenerated wood powder with the granularity of 0.1-80 mu m.

(2) Screening regenerated wood powder: and soaking the regenerated wood powder in water, stirring at the rotating speed of 30rpm for 50min, standing for precipitation for 60min, removing supernatant to remove light impurities in the regenerated wood powder, and collecting the precipitated regenerated wood powder.

(3) And (3) repeating the step (2) for 3 times, drying the finally collected regenerated wood powder at 60 ℃ for 3 hours, and putting the regenerated wood powder into absolute ethyl alcohol for magnetic separation to remove metal impurities. And drying the regenerated wood flour subjected to magnetic separation at 60 ℃ for 5 hours, and finally removing heavy impurities through air flow separation to obtain the separated regenerated wood flour.

(4) Preparing modified regenerated wood powder: placing the sorted and regenerated wood powder into hot water at 70 ℃, stirring for 5min to enable the wood powder to be fully soaked in the water, and then mixing the sorted and regenerated wood powder, acetic anhydride, maleic anhydride and water according to a mass ratio of 1:10:10:160, adding acetic anhydride and maleic anhydride into the hot water in sequence to react for 30min. And filtering the regenerated wood powder in the reaction system after the reaction is finished, and drying the regenerated wood powder for 2 hours at the temperature of 80 ℃ to obtain the modified wood powder precursor.

(5) Mixing the modified wood flour precursor with water, and then mixing the modified wood flour precursor, the silane coupling agent and the water according to the mass ratio of 1:10:160, adding a silane coupling agent KH550, then adding nitric acid, enabling the concentration of the nitric acid in a reaction system to be 0.03mol/L, reacting for 20min, and then adding ammonium ceric nitrate and butyl acrylate, wherein the concentration of the ammonium ceric nitrate in the reaction system is 0.002mol/L, and the mass ratio of the butyl acrylate to the modified wood powder precursor is 1:1, continuously reacting for 20min, adding hydroquinone to terminate the reaction, filtering out a modified wood flour precursor in the reaction system, washing with ethanol, and finally drying at the temperature of 70 ℃ for 3h to obtain the modified wood flour.

2. A preparation method of a 3D printing heat-preservation cementing material containing modified wood powder comprises the following steps:

(i) Weighing the following raw materials in parts by weight:

the magnesium phosphate composite material is composed of dead-burned magnesium oxide, monopotassium phosphate, borax and portland cement, wherein: the mass ratio of the dead burned magnesium oxide to the monopotassium phosphate is 7:2; the borax doping amount is 8 percent of the total mass of the magnesium oxide and the potassium dihydrogen phosphate; the mixing amount of the portland cement is 22% of the total mass of the magnesium oxide, the potassium dihydrogen phosphate and the borax.

The mineral admixture is prepared from quartz sand, slag micropowder and fly ash according to the weight ratio of 2:1:1, wherein: the granularity of the quartz sand is 50-200 mu m, the granularity of the slag micro powder is 5-100 mu m, and the granularity of the fly ash is 0.1-50 mu m.

The thickening agent is prepared from silica fume and hydroxypropyl methyl cellulose ether according to the weight ratio of 10:3 in mass ratio.

(ii) And mixing the magnesium phosphate composite material, the mineral admixture, the thickening agent and the modified wood powder, and stirring for 15min to obtain a solid mixture.

(iii) And dissolving the water reducer and the retarder in the water, and stirring for 5min to obtain a liquid mixture.

(iv) And adding the liquid mixture into the solid mixture, and stirring for 20min to obtain the 3D printing heat-preservation gel material containing the modified wood powder, as shown in figure 1.

Second embodiment

1. A preparation method of modified wood flour comprises the following steps:

(1) Preparing regenerated wood powder: the construction waste wood is ground by a grinder to prepare regenerated wood powder with the granularity of 50-120 mu m.

(2) Screening regenerated wood powder: and soaking the regenerated wood powder in water, stirring at the rotating speed of 40rpm for 30min, standing for precipitation for 60min, removing supernate to remove light impurities in the regenerated wood powder, and collecting the precipitated regenerated wood powder.

(3) And (3) repeating the step (2) for 2 times, drying the finally collected regenerated wood powder at 50 ℃ for 5 hours, and putting the regenerated wood powder into absolute ethyl alcohol for magnetic separation to remove metal impurities. And drying the regenerated wood flour subjected to magnetic separation at 50 ℃ for 6 hours, and finally removing heavy impurities through air flow separation to obtain the separated regenerated wood flour.

(4) Preparing modified regenerated wood powder: placing the sorted and regenerated wood powder into hot water at 40 ℃ and stirring for 5min to enable the wood powder to be fully soaked in the water, and then mixing the sorted and regenerated wood powder, acetic anhydride, maleic anhydride and water according to a mass ratio of 1:10:10:100, adding acetic anhydride and maleic anhydride into the hot water in turn to react for 10min. And filtering the regenerated wood powder in the reaction system after the reaction is finished, and drying at 105 ℃ for 4 hours to obtain the modified wood powder precursor.

(5) Mixing the modified wood flour precursor with water, and then mixing the modified wood flour precursor, the silane coupling agent and the water according to the mass ratio of 1:10: adding a silane coupling agent according to the proportion of 100, then adding nitric acid, enabling the concentration of the nitric acid in a reaction system to be 0.01mol/L, reacting for 20min, and then adding ammonium ceric nitrate and hydroxybutyl vinyl ether, wherein the concentration of the ammonium ceric nitrate in the reaction system is 0.001mol/L, and the mass ratio of the hydroxybutyl vinyl ether to the modified wood flour precursor is 1:1, continuing to react for 15min, adding hydroquinone to terminate the reaction, filtering out a modified wood flour precursor in the reaction system, washing with methanol, and finally drying at the temperature of 80 ℃ for 4h to obtain the modified wood flour.

(i) Weighing the following raw materials in parts by weight:

the magnesium phosphate composite material is composed of dead-burned magnesium oxide, monopotassium phosphate, borax and portland cement, wherein: the mass ratio of the dead burned magnesium oxide to the monopotassium phosphate is 7:1; the borax mixing amount is 6% of the total mass of the magnesium oxide and the potassium dihydrogen phosphate; the mixing amount of the portland cement is 10% of the total mass of the magnesium oxide, the potassium dihydrogen phosphate and the borax.

The mineral admixture is prepared from quartz sand, slag micropowder and fly ash according to the ratio of 2:1:2, wherein: the granularity of the quartz sand is 50-200 mu m, the granularity of the slag micro powder is 5-100 mu m, and the granularity of the fly ash is 0.1-50 mu m.

The thickening agent is prepared from silica fume and hydroxypropyl methyl cellulose ether according to the weight ratio of 5:1, in terms of mass ratio.

(iv) And adding the liquid mixture into the solid mixture, and stirring for 20min to obtain the 3D printing heat-preservation cementing material containing the modified wood powder.

Third embodiment

1. A preparation method of modified wood flour comprises the following steps:

(1) Preparing regenerated wood powder: the construction waste wood is ground by a grinder to prepare regenerated wood powder with the granularity of 110-200 mu m.

(2) Screening regenerated wood powder: and soaking the regenerated wood powder in water, stirring at the rotating speed of 20rpm for 60min, standing for precipitation for 60min, removing supernatant to remove light impurities in the regenerated wood powder, and collecting the precipitated regenerated wood powder.

(3) And (3) repeating the step (2) for 3 times, drying the finally collected regenerated wood flour at 55 ℃ for 4 hours, and placing the regenerated wood flour into absolute ethyl alcohol for magnetic separation to remove metal impurities. And drying the regenerated wood flour subjected to magnetic separation at 60 ℃ for 6 hours, and finally removing heavy impurities through air flow separation to obtain the separated regenerated wood flour.

(4) Preparing modified regenerated wood powder: placing the sorted and regenerated wood powder into hot water at 80 ℃, stirring for 5min to enable the wood powder to be fully soaked in the water, and then mixing the sorted and regenerated wood powder, acetic anhydride, maleic anhydride and water according to a mass ratio of 1:10:10:200, adding acetic anhydride and maleic anhydride into the hot water in sequence to react for 40min. And filtering the regenerated wood powder in the reaction system after the reaction is finished, and drying the regenerated wood powder for 3 hours at the temperature of 90 ℃ to obtain the modified wood powder precursor.

(5) Mixing the modified wood flour precursor with water, and then mixing the modified wood flour precursor, the silane coupling agent and the water according to the mass ratio of 1:10: adding a silane coupling agent according to the proportion of 200, then adding nitric acid, enabling the concentration of the nitric acid in a reaction system to be 0.05mol/L, reacting for 30min, and then adding ammonium ceric nitrate and isobutyl vinyl ether, wherein the concentration of the ammonium ceric nitrate in the reaction system is 0.003mol/L, and the mass ratio of the isobutyl vinyl ether to the modified wood flour precursor is 1:1, continuously reacting for 25min, adding hydroquinone to terminate the reaction, filtering out a modified wood powder precursor in the reaction system, washing with ethanol, and finally drying at the temperature of 75 ℃ for 3h to obtain the modified wood powder.

(i) Weighing the following raw materials in parts by weight:

the magnesium phosphate composite material is composed of dead-burned magnesium oxide, monopotassium phosphate, borax and portland cement, wherein: the mass ratio of the dead burned magnesium oxide to the monopotassium phosphate is 7:3; the borax doping amount is 10% of the total mass of the magnesium oxide and the potassium dihydrogen phosphate; the mixing amount of the portland cement is 30% of the total mass of the magnesium oxide, the potassium dihydrogen phosphate and the borax.

The mineral admixture is prepared from quartz sand, slag micropowder and fly ash according to the weight ratio of 2:1:1.7, wherein: the granularity of the quartz sand is 50-200 mu m, the granularity of the slag micro powder is 5-100 mu m, and the granularity of the fly ash is 0.1-50 mu m.

The thickening agent is prepared from silica fume and hydroxypropyl methyl cellulose ether according to the weight ratio of 10:1, in terms of mass ratio.

The retarder is compounded by 0.1 part by weight of triethanolamine and 0.1 part by weight of polyvinyl alcohol.

Fourth embodiment

A preparation method of a 3D printing heat-preservation cementing material containing modified wood powder comprises the following steps:

(i) Weighing the following raw materials in parts by weight:

the magnesium phosphate composite material is composed of dead-burned magnesium oxide, monopotassium phosphate, borax and portland cement, wherein: the mass ratio of the dead burned magnesium oxide to the monopotassium phosphate is 7:1; the borax mixing amount is 6.5 percent of the total mass of the magnesium oxide and the potassium dihydrogen phosphate; the mixing amount of the portland cement is 25% of the total mass of the magnesium oxide, the potassium dihydrogen phosphate and the borax.

Fifth embodiment

(i) Weighing the following raw materials in parts by weight:

the magnesium phosphate composite material is composed of dead-burned magnesium oxide, monopotassium phosphate, borax and portland cement, wherein: the mass ratio of the dead burned magnesium oxide to the monopotassium phosphate is 7:1.8; the borax mixing amount is 7% of the total mass of the magnesium oxide and the potassium dihydrogen phosphate; the mixing amount of the portland cement is 14% of the total mass of the magnesium oxide, the potassium dihydrogen phosphate and the borax.

Sixth embodiment

A preparation method of a 3D printing heat-preservation cementing material containing modified wood flour is different from the first embodiment in that: the modified polyphenyl particle also comprises 3 parts by weight of modified polyphenyl particles, and the preparation method of the modified polyphenyl particles comprises the following steps: according to the mass ratio of the polyphenyl particles, the silane coupling agent and the hydroxypropyl methyl cellulose ether of 10:1:1, soaking the polyphenyl particles in the mixture of the silane coupling agent and the hydroxypropyl methyl cellulose ether for 30min to obtain the polyphenyl particles.

(i) When the 3D printing heat-preservation cementing material containing the modified wood flour is prepared, the magnesium phosphate composite material, the mineral admixture, the thickening agent, the modified wood flour and the polystyrene particles are mixed and stirred for 15min, and a solid mixture is obtained.

(ii) And dissolving the water reducer and the retarder in the water, and stirring for 5min to obtain a liquid mixture.

(iii) And adding the liquid mixture into the solid mixture, and stirring for 20min to obtain the 3D printing heat-preservation cementing material containing the modified wood powder.

Seventh embodiment

The preparation method of the 3D printing heat-preservation cementing material containing the modified wood powder is different from the first embodiment in that: the modified polyphenyl particle also comprises 5 parts by weight of modified polyphenyl particles, and the preparation method of the modified polyphenyl particles comprises the following steps: according to the mass ratio of the polyphenyl particles, the silane coupling agent and the hydroxypropyl methyl cellulose ether of 10:1:2, soaking the polyphenyl particles in the mixture of the silane coupling agent and the hydroxypropyl methyl cellulose ether for 50min to obtain the polyphenyl particles.

Eighth embodiment

A preparation method of a 3D printing heat-preservation cementing material containing modified wood flour is different from the first embodiment in that: the modified polyphenyl particle also comprises 0.5 part by weight of modified polyphenyl particles, and the preparation method of the modified polyphenyl particles comprises the following steps: according to the mass ratio of the polyphenyl particles, the silane coupling agent and the hydroxypropyl methyl cellulose ether of 10:1:2, soaking the polyphenyl particles in the mixture of the silane coupling agent and the hydroxypropyl methyl cellulose ether for 50min to obtain the polyphenyl particles.

(i) When the 3D printing heat-preservation cementing material containing the modified wood powder is prepared, the magnesium phosphate composite material, the mineral admixture, the thickening agent, the modified wood powder and the polyphenyl granules are mixed and stirred for 15min to obtain a solid mixture.

Ninth embodiment

A preparation method of a 3D printing binding material is different from the first embodiment in that: modified wood powder is not added in the raw materials for preparing the 3D printing cementing material.

Tenth embodiment

A preparation method of a 3D printing gel material is different from the first embodiment in that: in the preparation raw material of the 3D printing gel material, wood powder which is not subjected to modification treatment is adopted to replace the modified wood powder. The method for producing wood flour according to the first embodiment comprises steps (1) to (3):

(2) Screening regenerated wood powder: and soaking the regenerated wood powder in water, stirring at the rotating speed of 30rpm for 50min, standing for precipitation for 60min, removing supernate to remove light impurities in the regenerated wood powder, and collecting the precipitated regenerated wood powder.

(3) And (3) repeating the step (2) for 3 times, drying the finally collected regenerated wood powder at 60 ℃ for 3 hours, and putting the regenerated wood powder into absolute ethyl alcohol for magnetic separation to remove metal impurities. And drying the regenerated wood flour subjected to magnetic separation at 60 ℃ for 5h, and finally removing heavy impurities through air flow separation to obtain the wood flour.

Eleventh embodiment

A preparation method of a 3D printing binding material is different from the first embodiment in that: in the raw materials for preparing the 3D printing cementing material, the preparation method of the modified wood powder is as follows:

(3) And (3) repeating the step (2) for 3 times, drying the finally collected regenerated wood powder at 60 ℃ for 3 hours, and putting the regenerated wood powder into absolute ethyl alcohol for magnetic separation to remove metal impurities. And drying the regenerated wood flour subjected to magnetic separation at 60 ℃ for 5h, and finally removing heavy impurities through air flow separation to obtain the separated regenerated wood flour.

(4) Preparing modified regenerated wood powder: placing the sorted and regenerated wood powder into hot water at 70 ℃, stirring for 5min to enable the wood powder to be fully soaked in the water, and then mixing the sorted and regenerated wood powder, acetic anhydride, maleic anhydride and water according to a mass ratio of 1:10:10:160, adding acetic anhydride and maleic anhydride into the hot water in sequence to react for 40min. And filtering the regenerated wood powder in the reaction system after the reaction is finished, and drying the regenerated wood powder for 2 hours at the temperature of 80 ℃ to obtain the modified wood powder.

Twelfth embodiment

A preparation method of a 3D printing gel material is different from the first embodiment in that: in the raw materials for preparing the 3D printing cementing material, the preparation method of the modified wood powder is as follows:

(4) Preparing modified regenerated wood powder: placing the sorted and regenerated wood powder into hot water at 70 ℃, stirring for 5min to enable the wood powder to be fully soaked in the water, and then mixing the sorted and regenerated wood powder, acetic anhydride, maleic anhydride and water according to a mass ratio of 1:10:10:160, adding acetic anhydride and maleic anhydride into the hot water in sequence to react for 40min. And filtering the regenerated wood powder in the reaction system after the reaction is finished, and drying the regenerated wood powder for 2 hours at the temperature of 80 ℃ to obtain the modified wood powder precursor.

(5) Mixing the modified wood flour precursor with water, and then mixing the modified wood flour precursor, the silane coupling agent and the water according to the mass ratio of 1:10:160, adding a silane coupling agent KH550, then adding nitric acid, enabling the concentration of the nitric acid in the reaction system to be 0.03mol/L, reacting for 20min, filtering out a modified wood powder precursor in the reaction system, washing with ethanol, and finally drying at 70 ℃ for 3h to obtain the modified wood powder.

Performance testing

The 3D printing cementitious material containing modified wood flour prepared in each example was prepared into test pieces by using a 3D printing technique, and then the performance indexes of each test piece were tested, and the performance test results are shown in tables 1 and 2 below. Wherein the thixotropy is measured using a sakemars 40 rheometer from seimer feishel. The sample with the thermal conductivity of 300 multiplied by 300mm is obtained by testing in a thermal conductivity meter. The compressive strength was measured using a U.S. MTS Universal tester. And calculating the average deformation of the 3D printing structure deformation rate in the three XYZ directions after the printing slurry is stable. The dry density was 100 ± 5 ℃ and dried for 2 hours, and the mass per unit volume of the test piece was printed, and the results obtained by weighing calculation were shown in tables 1 and 2. It can be seen that the overall performance of the test pieces obtained by 3D printing the binding materials of the first to eighth embodiments is effectively improved compared with the ninth to twelfth embodiments.

TABLE 1

Example number	First of all	Second one	Third	Fourth step of	Fifth aspect of the invention	Sixth aspect of the invention
							Dry density/kg/m ³	1980	2058	1904	1969	1992	852
Thermal conductivity/W/(m. K)	0.432	0.475	0.402	0.421	0.414	0.145
							Structural deformation rate/%)	8.71	10.24	5.32	12.69	15.23	8.94
Compressive strength/MPa (3 d)	29.84	35.21	27.68	13.22	28.11	9.52
							Thixotropy/%	81	72	91	61	47	80

TABLE 2

Example number	Seventh aspect of the invention	Eighth item	Ninth item	Tenth item	Eleven points of the design	Twelve aspects
							Dry density/kg/m ³	621	1209	2251	1977	1978	1982
Thermal conductivity/W/(m.K)	0.113	0.212	0.492	0.431	0.451	0.453
							Structural deformation rate/%)	6.04	11.36	19.84	15.66	11.22	10.38
Compressive strength/MPa (3 d)	8.11	14.98	36.54	23.61	27.31	28.91
							Thixotropy/%)	85	65	55	66	71	72

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described above, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The 3D printing heat-preservation cementing material containing modified wood powder is characterized by comprising the following raw materials in parts by weight: 70-100 parts of magnesium phosphate composite material; 5 to 15 parts of mineral admixture; 5-20 parts of modified wood powder; 1.2 to 5.6 parts of an auxiliary agent; 15-20 parts of water;

the preparation method of the modified wood powder comprises the following steps:

(1) Placing wood powder in water, then sequentially adding acetic anhydride and maleic anhydride, and drying after the reaction is finished to obtain a modified wood powder precursor;

(2) Placing the modified wood flour precursor in water, then sequentially adding a silane coupling agent and nitric acid, continuously adding ammonium ceric nitrate and a vinyl monomer after reaction, washing the modified wood flour precursor after the reaction is finished, and drying to obtain the modified wood flour;

the vinyl monomer comprises any one or two of butyl acrylate, hydroxybutyl vinyl ether and isobutyl vinyl ether.

2. The 3D printing heat-preservation gel material containing modified wood flour as claimed in claim 1, wherein in the step (1), the mass ratio of wood flour to acetic anhydride to maleic anhydride to water is 1:10:10:100 to 200.

3. The 3D printing thermal insulation binding material containing modified wood flour as claimed in claim 1, wherein in the step (1), the reaction temperature is 40 to 70 ℃ and the reaction time is 10 to 40min.

4. The 3D printing thermal insulation binding material containing modified wood flour as claimed in claim 1, wherein in the step (1), the drying temperature is 80-105 ℃, and the drying time is 2-4 h.

5. The modified wood flour-containing 3D printing heat-preservation gel material according to claim 1, wherein in the step (2), the mass ratio of the modified wood flour precursor to the silane coupling agent to the water is 1:10:100 to 200.

6. The 3D printing thermal insulation gelling material containing modified wood flour as claimed in claim 1, wherein in the step (2), the addition amount of the nitric acid is such that the concentration of the nitric acid in the reaction system is 0.01 to 0.05mol/L.

7. The 3D printing thermal insulation gelling material containing modified wood flour as claimed in claim 1, wherein in the step (2), the addition amount of the ammonium cerium nitrate is such that the concentration of the ammonium cerium nitrate in the reaction system is 0.001 to 0.003mol/L.

8. The 3D printing heat-preservation gel material containing modified wood flour as claimed in claim 1, wherein in the step (2), the mass ratio of the modified wood flour precursor to the vinyl monomer is 1:1.

9. the 3D printing thermal insulation gelling material containing the modified wood powder as claimed in claim 1, wherein in the step (2), the cerium ammonium nitrate and the vinyl monomer are added after the reaction is carried out for 20 to 30min, the reaction is carried out for 15 to 25min, and then hydroquinone is added to terminate the reaction.

10. The modified wood flour-containing 3D printing thermal insulation gel material as claimed in claim 1, wherein in the step (2), the modified wood flour precursor is washed by any one of ethanol and methanol detergents.

11. The 3D printing thermal insulation binding material containing modified wood flour as claimed in claim 1, wherein in the step (2), the drying temperature is 70-80 ℃, and the drying time is 3-4 h.

12. The 3D printing heat-preservation gel material containing the modified wood powder as claimed in claim 1, wherein the raw material of the 3D printing heat-preservation gel material containing the modified wood powder further comprises 0.5-5 parts by weight of modified polyphenyl particles; the modified polyphenylene particle comprises: the polyphenyl granules are obtained by soaking the polyphenyl granules in a mixed solution of a silane coupling agent and hydroxypropyl methyl cellulose.

13. The 3D printing heat-preservation gel material containing modified wood flour as claimed in claim 12, wherein the mass ratio of the polyphenyl particles, the silane coupling agent and the hydroxypropyl methyl cellulose ether is 10:1:1 to 2.

14. The 3D printing thermal insulation binding material containing modified wood flour as claimed in claim 12, wherein the soaking time is 30 to 50min.

15. The 3D printing thermal insulation cementitious material containing modified wood flour according to any one of claims 1 to 14, characterized in that the auxiliary agent comprises at least one of a thickener, a retarder, a water reducing agent.

16. The 3D printing heat-preservation gel material containing the modified wood powder as claimed in claim 15, wherein the auxiliary agent is prepared from a thickening agent, a retarder and a water reducing agent according to the following weight parts of 1-5: 0.1 to 0.2 parts by weight: 0.1 to 0.4 part by weight.

17. The 3D printing thermal insulation cementitious material containing modified wood flour according to claim 15, characterized in that the thickener is a composite thickener consisting of silica fume and hydroxypropyl methyl cellulose ether.

18. The 3D printing heat-preservation gel material containing modified wood flour as claimed in claim 17, wherein the mass ratio of the silica fume to the hydroxypropyl methyl cellulose ether is 10:1 to 3.

19. The modified wood flour-containing 3D printing thermal insulation cementitious material as claimed in claim 15, wherein the water reducing agent comprises: any one of a polycarboxylic acid water reducing agent and a naphthalene high-efficiency water reducing agent.

20. The 3D printed thermal insulation cementitious material containing modified wood flour according to claim 15, wherein the set retarder comprises: one or two of triethanolamine, polyvinyl alcohol and sodium chloride.

21. The modified wood flour-containing 3D printed thermal insulation cementitious material according to any one of claims 1 to 14, wherein the magnesium phosphate composite material comprises: dead burning magnesium oxide, potassium dihydrogen phosphate, borax and silicate cement.

22. The 3D printing heat-preservation gel material containing the modified wood flour as claimed in claim 21, wherein the mass ratio of the dead burned magnesium oxide to the monopotassium phosphate is 7:1 to 3, wherein the borax doping amount is 6 to 10 percent of the total mass of the magnesium oxide and the potassium dihydrogen phosphate; the mixing amount of the portland cement is 10 to 30 percent of the total mass of the magnesium oxide, the potassium dihydrogen phosphate and the borax.

23. The 3D printing thermal insulation cementitious material containing modified wood flour according to any one of claims 1 to 14, characterized in that the mineral admixture consists of quartz sand, slag micropowder and fly ash.

24. The modified wood flour-containing 3D printing heat-preservation cementing material according to claim 23, characterized in that the mass ratio of the quartz sand, the slag micropowder and the fly ash is 2:1:1 to 2.

25. The 3D printing thermal insulation cementing material containing modified wood powder as claimed in claim 24, characterized in that the granularity of the quartz sand is 50 to 200 μm, the granularity of the slag micropowder is 5 to 100 μm, and the granularity of the fly ash is 0.1 to 50 μm.

26. The preparation method of the 3D printing heat preservation gel material containing the modified wood flour as claimed in any one of claims 1 to 25, characterized by comprising the following steps:

(i) Uniformly mixing the magnesium phosphate composite material, the mineral admixture and the modified wood powder to obtain a solid mixture;

(ii) Dissolving the auxiliary agent in the water, and uniformly stirring to obtain a liquid mixture;

27. The method for preparing the 3D printing thermal insulation gelling material containing the modified wood flour as claimed in claim 26, wherein the solid mixture further comprises modified polyphenyl particles, and the modified polyphenyl particles comprise: the polyphenyl granules are soaked in a mixed solution of a silane coupling agent and hydroxypropyl methyl cellulose.

28. Use of the modified wood flour-containing 3D printed thermal insulation cementitious material according to any one of claims 1 to 25 or the modified wood flour-containing 3D printed thermal insulation cementitious material obtained by the preparation method according to claim 26 or 27 in the field of construction engineering.