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CN-122010517-A - Plant fiber composite reinforced light anti-flex gypsum

CN122010517ACN 122010517 ACN122010517 ACN 122010517ACN-122010517-A

Abstract

The invention relates to the technical field of inorganic composite materials, in particular to a plant fiber composite reinforced light-weight anti-flex gypsum board. The plant short fiber adopted by the gypsum board is subjected to calcium hydroxide solution impregnation and sulfur dioxide gas fumigation treatment, a calcium sulfite/calcium sulfate microcrystalline coating layer is generated on the surface of the plant short fiber in situ, so that the interfacial binding force between the fiber and a gypsum matrix is enhanced. The gypsum board prepared by the invention has excellent flexural property and impact strength while keeping light weight, and solves the problem of insufficient mechanical property of the traditional light gypsum board.

Inventors

  • YANG YICHEN
  • ZHOU CHUANMING

Assignees

  • 泰山石膏(宜昌)有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (7)

  1. 1. The plant fiber composite reinforced light anti-flex gypsum is characterized by comprising the following components in parts by mass: 100 parts of building gypsum powder, 5-15 parts of modified plant short fibers, 1-3 parts of cellulose nanofibrils, 10-30 parts of auxiliary cementing materials, 0.3-1.2 parts of polycarboxylic acid water reducer, 0.3-1.5 parts of calcium stearate and 0.05-0.3 part of protein retarder; The raw material of the modified plant short fiber is wheat straw or rice straw, the length of the modified plant short fiber is 1-3 mm, the length-diameter ratio of the modified plant short fiber is more than 20, and the preparation steps of the modified plant short fiber are as follows: (1) Immersing plant short fibers in a calcium hydroxide solution with the concentration of 1.5-2.2 g/L, wherein the mass ratio of the solution to the fibers is 10:1-30:1, immersing for 10-60 min at 15-35 ℃, taking out the fibers after immersing, and draining until no drip exists, so as to obtain a calcified fiber precursor in a wet state; (2) And placing the drained calcified fibers in a closed reactor, introducing sulfur dioxide gas with the volume fraction of 5-15%, fumigating and reacting for 10-30 min under the conditions of the relative humidity of 60-80% and the temperature of 15-35 ℃, taking out the fibers, and drying at 60-80 ℃ to obtain the modified plant short fibers.
  2. 2. The plant fiber composite reinforced lightweight flex-resistant gypsum according to claim 1, wherein the specific surface area of the building gypsum powder is 300m 2 /kg~500m 2 /kg and the 120 mesh screen residue is <5%.
  3. 3. The plant fiber composite reinforced lightweight flex-gypsum board of claim 1, wherein said supplementary cementitious material is granulated blast furnace slag powder.
  4. 4. A method for preparing the plant fiber composite reinforced light-weight flexural gypsum board as claimed in any one of claims 1 to 3, which is characterized by comprising the following steps: step S1, carrying out first dry mixing on building gypsum powder, auxiliary cementing materials, calcium stearate and protein retarder, and then adding a polycarboxylic acid water reducer for second dry mixing to obtain uniform mixed dry powder; S2, pouring the mixed dry powder into a stirrer, adding cellulose nanofibrils and water accounting for 55-75% of the mass of gypsum powder in the stirring state, stirring for 1-2 min to form uniform matrix slurry, adding modified plant short fibers, and stirring at high speed to form uniform fiber composite slurry; S3, injecting the fiber composite slurry into a forming die paved with a 300-400 mesh filter screen, starting a vacuum system, enabling the vacuum degree of the die to be minus 0.08-minus 0.092MPa, carrying out suction filtration and dehydration until the water content of the slurry is 8-12%, forming a wet slab with the density of 1100-1300 kg/m 3 , then transferring to a hot press, and curing for 15-30 min under the plane pressure of 1-2.5 MPa and the temperature of 60-80 ℃; And S4, releasing pressure and demoulding, placing the plate blank in a circulating hot air drying oven for drying, and cutting to a fixed length to obtain the plant fiber composite reinforced light-weight anti-flex gypsum.
  5. 5. The method for preparing the plant fiber composite reinforced light weight flexural gypsum board of claim 4 characterized in that in step S1, after a second dry blending to obtain a uniform mixed dry powder, the mixed dry powder is left to stand and age for 5-15 min.
  6. 6. The method for preparing the plant fiber composite reinforced light weight flex-resistant gypsum according to claim 4, wherein in the step S2, cellulose nanofibrils are mixed with water with the mass of 20-50 times before being added, and pre-dispersed by ultrasonic treatment with the power of 300-500W for 5-15 min.
  7. 7. The method for preparing a plant fiber composite reinforced lightweight flex-gypsum according to claim 4, wherein in the step S3, while applying vacuum pressure, mechanical vibration is applied to the mold in a vertical direction with a frequency of 25-50 hz, and the duration of vibration is the whole suction filtration dehydration period.

Description

Plant fiber composite reinforced light anti-flex gypsum Technical Field The invention relates to the technical field of inorganic composite materials, in particular to a plant fiber composite reinforced light-weight anti-flex gypsum board. Background The gypsum board is widely used as a building inner wall, partition and ceiling material, and has the core performance requirements of light weight and enough mechanical strength, in particular to flexural performance. The traditional gypsum board realizes light weight mainly through two ways, namely, firstly, light aggregate is doped into a matrix or chemical foaming is introduced into the matrix to form a porous structure, and secondly, low-density reinforcing fibers are used. However, these methods generally suffer from a loss of strength, particularly a significant decrease in flexural strength and toughness, which results in the problems of breakage, corner breakage, etc. of the sheet material during transportation, installation and loading, and limits its application in applications where higher structural safety and dimensional stability are required. Plant short fibers such as straw and rice straw are used as reinforcing phase to replace part of traditional fibers, and are regarded as a potential technical path, because of low cost and contribution to adjusting material density, but natural plant fibers have poor physical and chemical compatibility with inorganic gypsum matrix and weak interface bonding, on one hand, water film layers exist between the fibers and gypsum slurry due to the hydrophilicity of the fibers, so that mechanical anchoring force is weakened, on the other hand, the elastic modulus of the fibers and the gypsum slurry are not matched, and the stress transfer efficiency is low, so that the reinforcing and toughening effects of the fibers do not reach theoretical expectations, and the bending strength of a plate is limited by simply adding the plant short fibers, and even the bending strength of the plate is reduced due to the introduction of structural defects. In order to further improve the interface performance, the prior art carries out various pretreatment on the fiber, such as alkali treatment, coupling agent coating and the like, and the methods have certain effects, but often have the limitations that the chemical bonding between the modified layer and the gypsum hydration product is not strong, or the process is complex, the cost is obviously increased, and the strength of the fiber body can be damaged. Meanwhile, the final performance of the plate also depends on the forming process, and the traditional casting forming and natural dehydration modes are difficult to realize densification of slurry while ensuring uniform dispersion of fibers. In summary, the prior gypsum board technology is difficult to realize high bending strength and high toughness on the premise of maintaining light weight, and has the core problems of lacking a modification method capable of improving the interfacial adhesion between plant fibers and a gypsum matrix and a set of matching process capable of realizing uniform dispersion molding of the fibers. Chinese patent discloses publication No. CN103420662a, disclosing an integrally reinforced gypsum board. The integral reinforced gypsum board comprises a body and a reinforcing material net layer uniformly arranged in the body, wherein the ingredients of the body comprise, by weight, 100 parts of gypsum powder, 5-10 parts of defibrinated plant fibers, 5-30mm of plant fibers, 10-20dtex of linear density, 100-150 parts of fly ash, 1000-1200 meshes of fineness of the fly ash, 0.5-1 part of coupling agent, 5-7 parts of adhesive, 1-2 parts of sodium sulfate and 40-60 parts of water, wherein the fineness of the gypsum powder is 750-1000 meshes, and the gypsum powder is a mixture of semi-hydrated gypsum and dihydrate gypsum with a mass ratio of 8:1-1:2. The invention adopts the plant fiber and the reinforcing material net layer to reinforce the gypsum board, thereby effectively improving the strength of the gypsum board, improving the quality of the gypsum board, reducing the production difficulty and the process difficulty, simultaneously reducing the production cost of the gypsum board and improving the enterprise benefit. However, the gypsum board prepared by the invention has the characteristics of high strength and the like, and does not have the performances of light weight, excellent flexure resistance and the like. Disclosure of Invention The invention aims to provide a plant fiber composite reinforced light-weight flex-resistant gypsum board, which solves the problem that the prior art lacks a modification method capable of improving the interfacial adhesion between plant fibers and a gypsum matrix and a set of technology capable of realizing uniform dispersion and forming of fibers. In order to achieve the above purpose, the present invention provides the following technical solutions: The plant fib