Preparation and Process Optimization of Hot-Pressed Straw-Sulfate Magnesium Cement Composite Panels

Abstract

Magnesium oxysulfide cement, due to its unique composition, is lightweight and highly fire-resistant. As a new type of inorganic cementitious material, it has considerable application potential in the production of artificial boards. Using wheat straw as the raw material and magnesium oxysulfide cement as the adhesive, straw-magnesium oxysulfide cement artificial boards were prepared through uniform laying and hot pressing. The mechanical properties and water absorption expansion rate of the artificial boards were evaluated. The optimal process parameters were identified through orthogonal experiments. The results indicate that under the optimal conditions (12 min, 120 °C, 7.5 MPa), the manufactured board achieved peak performance. The static bending strength was 6.09 MPa, the elastic modulus was 764 MPa, and the internal bonding strength was 2.21 MPa. Additionally, the 2 h water absorption thickness expansion rate was 242.6%.

1. Introduction

With a global market value of 175.1 billion USD as of 2023, artificial boards are essential components in both the construction and manufacturing sectors. Their production involves hot pressing woody or other lignocellulose-based materials. The addition of synthetic adhesives is standard in this process and is crucial for ensuring the final product’s mechanical strength. Traditionally, artificial boards are produced primarily from wood as the base material. To improve performance, various adhesives are incorporated, most notably urea-formaldehyde (UF), phenolic (PF), and melamine-urea-formaldehyde (MUF) resins. , Although the use of wood can produce high-quality boards, it has led to large-scale logging, which in turn has caused a series of environmental problems, including land desertification and global warming. At the same time, while these adhesives significantly improve the dimensional stability and the physical and chemical properties of the boards, they also have notable drawbacks: they continuously release harmful substances such as formaldehyde during their service life, thereby polluting the environment and posing potential risks to human health. , Although existing studies have explored the application of natural binders, including lignin and tannin as well as protein-based and starch-based alternatives, − their complex processing requirements and high raw material costs have increased manufacturing expenses. Consequently, the substitution of wood with nonwood lignocellulosic biomass has garnered increasing attention as a feedstock for fabricating artificial boards. ,

Magnesium oxysulfide cement, an important inorganic cementitious material, forms a ternary gel structure of MGO-MgSO₄–H₂O through the reaction of active MgO with a magnesium sulfate solution of specific concentration. , Wood chip fiber composite ecological boards developed from this material have demonstrated significant technical advantages. Research conducted by Zhu and colleagues shows that fireproof boards prepared with magnesium oxysulfide cement, raw soil materials, fine wood chips, and PVA fibers not only meet the requirements of the GB/T 33544–2017 “Glass fiber and magnesium cement board” standard but also exhibit excellent engineering applicability. Chen et al. systematically studied the preparation process of magnesium cement-straw composite boards, innovatively applying fusion composite technology to address the shortcomings of the traditional process. Their economic and technical analysis demonstrated the feasibility of this approach for the high-value utilization of straw resources. Li developed straw-magnesia cement lightweight slabs, which performed exceptionally well in the Guiyang Railway Bureau Building project. This high-rise construction case fully verified the engineering applicability as well as the technical and economic advantages of the material. It is worth noting that the You team successfully developed a new type of low-carbon, biobased alkaline magnesium sulfate cement composite by incorporating recycled wood fibers and basalt fibers as lightweight reinforcing phases. The mechanical properties of this material, including flexural strength, were significantly improved, providing an innovative solution for the functional modification of magnesium sulfate cement. Xu et al. studied the preparation and application of straw-magnesium oxysulfide cement composite materials. Research indicates that when the straw powder content reaches 60%, the composite material exhibits the lowest apparent density, while its mechanical properties reach an optimal state. The 28-day flexural strength and compressive strength increase to 287.8% and 41.8% of the benchmark values, respectively. The performance test results meet the standard requirements of both GB/T 33544–2017 “Glass fiber and magnesium cement board” and GB/T 23451–2009 “Lightweight panels for partition wall used in buildings”. Compared with other adhesive materials, magnesium oxysulfide cement exhibits superior thermal stability, with a refractory temperature that can exceed 1200 °C, making it suitable for the production of certain refractory materials. In addition, compared with conventional Portland cement, magnesium oxysulfide cement is characterized by lower energy consumption, lower cost, and greater environmental friendliness. , However, in practical applications, magnesium oxychloride cement boards still present challenges such as low early strength and susceptibility to warping and deformation.

In recent years, wheat has become one of the most economically valuable staple food crops in the world. Its wide cultivation range and large output have secured its position as the second most produced grain worldwide. In 2023, global wheat production exceeded 786 million tons, according to statistical estimates, demonstrating the immense scale of agricultural production. It is worth noting that wheat straw, an important byproduct of wheat production, accounts for approximately 66.7% of the total biological output of wheat and has substantial potential for resource utilization. However, traditional uses of wheat straw, such as direct return to the field, feed processing, biogas fermentation, or use as fuel, generally face challenges such as low added value and low conversion efficiency. In contrast, the hot-pressing process transforms wheat straw into cardboard products, enabling efficient utilization of its fiber components while significantly increasing the economic benefits and social value of the resource. This approach opens a new path for the high-value utilization of agricultural waste.

Against this backdrop, this study uses wheat straw as a raw material with the aim of applying agricultural and forestry waste to the production of artificial boards, expanding its application fields, and contributing new ideas and methods to the development of green building materials.

2. Materials and Methods

2.1. Materials

Wheat straw (annual straw from the Yancheng area) was obtained; magnesium oxide (MgO) was purchased from Sinopharm Group Co., Ltd.; magnesium sulfate heptahydrate (MgSO₄·7H₂O) was purchased from Sinopharm Group Co., Ltd.; and citric acid (CA) was purchased from Tianjin Zhonglian Chemical Reagent Co., Ltd.

2.2. Equipment

An instant constant-temperature heating magnetic stirrer (model DF-101S, Shanghai Lichen Bangxi Instrument Technology Co., Ltd.); an electric mixer (model 350L direct connection, Xiangda Machinery Co., Ltd.); a flat vulcanizing machine (model DRB-100, Zhouderui Instrument & Equipment Co., Ltd.); and a microcomputer-controlled electronic universal testing machine (model QDW-50C, Shanghai Hualong Testing Instrument Co., Ltd.) were used.

3. Test Methods

The process flow for preparing the hot-pressed straw-magnesium oxychloride cement artificial boards is shown in Figure .

1.

Process flowchart.

3.1. Raw Material Processing

Wheat straw was crushed into fibers approximately 5 cm in length using a crusher for subsequent use. A solution was prepared by mixing water and a magnesium sulfate heptahydrate (MgSO₄·7H₂O) solution at a mass ratio of 1:1. Citric acid was added to this mixture at a dosage of 0.0225 times the mass of water, and the components were stirred thoroughly to form a homogeneous solution.

The adhesive was formulated according to the following mass proportions: light-burned magnesia (MgO), magnesium sulfate heptahydrate (MgSO₄·7H₂O), water, and citric acid in a ratio of 2.25:1:1:0.225. The adhesive system primarily consisted of light-burned magnesia and magnesium sulfate heptahydrate, with a molar ratio set at 13.8:1. For the molding process, the straw incorporation rate was set at 55%, meaning the mass of straw accounted for 55% of the total mass of the final composite board.

3.2. Sheet Material Preparation

The designed density of the straw-magnesium oxysulfide cement artificial board was 0.87 g/cm³, with dimensions of 400 mm × 400 mm × 10 mm. The material was air-dried under natural conditions and then evenly laid in molds for prepressing. It was subsequently placed in a vulcanizing machine for hot pressing. The straw-magnesium oxysulfide cement artificial board after hot pressing is shown in Figure .

2.

Straw-magnesium oxysulfide cement artificial board.

3.3. Orthogonal Experiment

The L₂₅(5³) orthogonal test scheme was selected, with hot-pressing time, hot-pressing temperature, and hot-pressing pressure as variables, as shown in Table . The standard orthogonal table L₂₅(5³) was used, consisting of 25 rows and 3 columns, with each column corresponding to a five-level factor. The experimental arrangement is shown in Table .

1. Factors and Levels.

Levels	A: Hot-pressing time/min	B: Hot-pressing temperature/°C	C: Hot-pressing pressure/MPa
1	6	60	5
2	8	80	7.5
3	10	100	10
4	12	120	12.5
5	14	140	15

2. Orthogonal Test Scheme.

	Factors
Test Number	A: Hot-pressing time/min	B: Hot-pressing temperature/°C	C: Hot-pressing pressure/MPa
1	1	1	1
2	1	2	2
3	1	3	3
4	1	4	4
5	1	5	5
6	2	1	2
7	2	2	3
8	2	3	4
9	2	4	5
10	2	5	1
11	3	1	3
12	3	2	4
13	3	3	5
14	3	4	1
15	3	5	2
16	4	1	4
17	4	2	5
18	4	3	1
19	4	4	2
20	4	5	3
21	5	1	5
22	5	2	1
23	5	3	2
24	5	4	3
25	5	5	4

3.4. Performance Testing of Artificial Boards

3.4.1. Static Bending Strength and Elastic Modulus

Twenty-five artificial boards were selected, from which specimens measuring 300 mm × 50 mm were cut. Specimens were graded from 1 to 25, and qualified specimens were selected. The support roller and loading roller were installed as shown in Figure , and the space between the two support rollers was adjusted to 150 mm. The machine was then started, and the maximum load at specimen failure was recorded.

3.

Static bending strength testing device.

The static bending strength of the specimen was calculated as follows:

$${\sigma }_b=\frac{F_{max}\times \iota }{b\times t^2}$$

The terms in the formula are as follows:

σ_b The static bending strength of the specimen, measured in megapascals (MPa);

F_max The maximum load at the time of specimen failure, measured in newtons (N);

ιThe distance between the two supports, measured in millimeters (mm);

bThe width of the specimen, measured in millimeters (mm);

tThe thickness of the specimen, measured in millimeters (mm);

The elastic modulus was calculated as follows:

$$E=\frac{{\iota }_1^3}{4\times b\times t^3}\times \frac{F_2-F_1}{a_2-a_1}$$

The terms in the formula are as follows:

EThe elastic modulus of the specimen, measured in megapascals (MPa);

ι ₁The distance between the two supports, measured in millimeters (mm)

bThe width of the specimen, measured in millimeters (mm);

tThe thickness of the specimen, measured in millimeters (mm);

F ₂ – F ₁Deflectionthe increase in load within the linear section of the load curve, measured in newtons (N);

a ₂ – a ₁The deformation of the specimen within the force range F ₂ – F ₁, measured in millimeters (mm);.

3.4.2. Internal Bonding Strength

The internal bonding strength is defined as the ratio of the maximum breaking tensile force applied perpendicular to the specimen surface during the failure process to the area of the specimen.

$${\sigma }_{\perp }=\frac{F_{max}}{\iota \times b}$$

The terms in the formula are as follows:

σ _⊥The internal bonding strength of the specimen, measured in megapascals (MPa);

F _max The maximum load at the time of specimen failure, measured in newtons (N);

ιThe length of the specimen, measured in millimeters (mm);

bThe width of the specimen, measured in millimeters (mm);

3.4.3. Two-Hour Water Absorption Thickness Swelling Rate

Twenty-five artificial boards were cut into specimens measuring 300 mm × 50 mm. Qualified specimens, labeled with grades 1–25, were selected. The initial thickness, h1, was measured at the center point, located at the intersection of the diagonals. Specimens were immersed in water for 2 h, after which surface moisture was removed and the thickness, h2, was measured. The 2-h water absorption thickness swelling rate, T, was calculated with an accuracy of 0.1%.

$$T=\frac{t_2-t_1}{t_1}\times 100$$

The terms in the formula are as follows:

TThe water absorption thickness swelling rate, expressed as a percentage, %;

t ₂The thickness of the specimen after immersion in water, measured in millimeters (mm);

t ₁The thickness of the specimen before immersion in water, measured in millimeters (mm);

3.5. Scanning Electron Microscopy (SEM)

In this study, the microstructure of the failed surface of the straw composite board was analyzed using scanning electron microscopy (SEM). Small samples were carefully cut from the failed surface and subjected to gold plating to enhance conductivity and improve SEM image quality. The samples were then observed and imaged with a Nova Nano SEM, which provided detailed information on the microstructure and morphological characteristics of the failure surface. This analysis reveals the material’s failure mechanism and the potential factors influencing its performance and durability.

3.6. Fourier Transform Infrared (FTIR)

Fourier Transform Infrared Spectroscopy (FTIR) analysis was carried out on a Nicolet iS10 spectrometer operated in transmission mode, covering a wavenumber range of 600–4000 cm^–1 with a resolution of 4 cm^–1.

4. Results and Discussion

4.1. Surface Morphology Analysis

The bonding mechanism of magnesium oxysulfide-straw composite materials was investigated through microscopic analysis. Microstructural images of magnesium oxysulfide-straw composite boards were obtained using scanning electron microscopy (SEM) (Figure a–f). Figure a shows that the natural structure of the straw fibers is well preserved. Their surfaces appear textured and rough, with numerous irregularly shaped pores distributed throughout. This rough structure is typically accompanied by a denser fiber arrangement, which increases the exposure of cellulose on the surface. Figure b shows that the bonding substrate (magnesium oxysulfide cement) is irregularly distributed on the straw surface, further contributing to its roughness. In Figure c, small protrusions formed by silica can be observed on the straw surface, along with natural pore structures that facilitate gas exchange. These protrusions contribute to the surface roughness of the wheat straw fibers. This roughness promotes the formation of a strong interfacial bond between adjacent wheat straw fiber layers and the magnesium oxysulfide cement by increasing frictional forces between them. Moreover, the rough surface enhances mechanical interlocking and adhesion between the fibers and the matrix, thereby optimizing their interaction and significantly improving stress transmission and load distribution within the composite material. See Figure d for their detailed structure. The untreated straw surface is covered by a dense, hydrophobic waxy cuticle (Figure e), which renders it strongly hydrophobic. After hot-pressing at elevated temperatures, the surface waxy layer is partially disrupted and softened (Figure f), leading to increased exposure of underlying hydrophilic lignocellulosic components. Concurrently, a relatively loose and porous interfacial transition zone is observed between the straw fiber and the cementitious matrix (Figure f). This transition zone, together with the exposed hydrophilic fiber surface, creates a rapid pathway for moisture transmission, which is identified as the key microscopic mechanism responsible for the anomalously high water absorption of the composite material.

4.

SEM images of refractive surfaces, (a) Product #19 (scale bar: 300 μm); (b) Product #19 (scale bar: 300 μm); (c) Product #19 (scale bar: 1 mm); (d) Enlarged view of the region marked in (c), showing stomata details; (e) Raw straw; (f) Fiber-matrix interface.

4.2. Chemical Structure Analysis

FTIR analysis provided information on the functional groups of the materials. The figure below compares the spectra of straw boards produced at different hot-pressing temperatures (Figure a,b). All samples exhibited a broad peak at 3270 cm^–1, attributed to the stretching vibration of the O–H bond (Figure a). The peak at 2918 cm^–1 corresponds to the stretching vibration of the C–H bond in alkanes. The absorption peak at 1730 cm^–1 is attributed to the stretching vibration of the acetyl CO bond in hemicellulose. The band at 1641 cm^–1 suggests the presence of proteinaceous (amide) or carbonyl functional groups (Figure b), with all observed peaks corresponding to the vibrations of specific bonds in the straw’s chemical components. When comparing the effects of temperature, a significant reduction in peak intensity is observed at 100, 120, and 140 °C relative to 60 and 80 °C. This reduction is particularly evident for the peaks at 1509, 1542, 1592, and 1623 cm^–1, which are assigned to the aromatic CC stretching vibrations of lignin. These results indicates that increasing the temperature degrades hemicellulose, lignin, and other components to a certain extent. At temperatures above 100 °C, lignin, hemicellulose, and other constituents are partially removed. This elevated temperature range is advantageous for improving the overall performance of the sheet.

5.

FTIR spectra of the samples at different heating temperature,(a) Product #19 (600–4000 cm^–1); (b) Product #19 (600–2000 cm^–1).

4.3. Performance Testing

This test mainly examined four properties of the sheet material: static bending strength, elastic modulus, internal bonding strength, and 2-h water absorption thickness swelling rate. The orthogonal test results are shown in Table .

3. Orthogonal Test Results.

	Variable			Result
Number	Hot-pressing time/min	Hot-pressing temperature/°C	Hot-pressing pressure/MPa	MOR (MPa)	MOE (MPa)	IB	2hTS (%)
1	1	1	1	0.1	0.8	0.03	142.3
2	1	2	2	0.7	37.6	0.07	151.9
3	1	3	3	0.7	49.8	0.17	91.8
4	1	4	4	2.2	624.7	0.89	150.1
5	1	5	5	1.5	106	0.5	248.7
6	2	1	2	0.3	14.7	0.16	146
7	2	2	3	0.9	61.9	0.22	109.5
8	2	3	4	0.9	53.1	0.28	192.7
9	2	4	5	3.1	815.9	1.53	151.3
10	2	5	1	1.8	243.9	0.67	161.8
11	3	1	3	0.8	68.8	0.25	181
12	3	2	4	0.7	58.2	0.51	154.1
13	3	3	5	1.6	148	0.5	114
14	3	4	1	4.6	523.1	1.52	218
15	3	5	2	3.2	319.8	0.77	179.3
16	4	1	4	0.6	42.1	0.32	169.2
17	4	2	5	1.1	130.5	0.45	173
18	4	3	1	0.6	58.4	0.23	103.5
19	4	4	2	6.1	764.9	2.21	242.6
20	4	5	3	3.3	518.4	1.14	177.5
21	5	1	5	0.6	48.6	0.21	191.4
22	5	2	1	0.7	70.3	0.44	133.1
23	5	3	2	2.5	370.5	1.16	134
24	5	4	3	2.8	451.5	1.42	153.7
25	5	5	4	4	491.7	2.73	150.1

4.3.1. Static Bending Strength

According to the static bending strength results summarized in Table , the most influential parameter was the hot-pressing temperature, followed by the duration and, finally, the pressure. The highest strength was achieved under the A4B4C2 combination, corresponding to a temperature of 120 °C, a duration of 12 min, and a pressure of 7.5 MPa.

4. Range Analysis and Calculation Results.

Factor project		Hot-pressing pressure/MPa	Hot-pressing temperature/°C	Hot-pressing time/min
MOR (MPa)	k1	1.03	0.49	1.54
	k2	1.4	0.83	2.57
	k3	2.18	1.23	1.69
	k4	2.34	3.75	1.7
	k5	2.12	2.78	1.57
	R	1.31	3.26	1.02
MOE (MPa)	k1	163.8	35	179.3
	k2	237.9	71.7	301.5
	k3	223.6	136	230.1
	k4	302.9	636	254
	k5	286.5	336	249.8
	R	139.1	601	122.2
IB (MPa)	k1	0.33	0.19	0.58
	k2	0.57	0.34	0.88
	k3	0.71	0.47	0.64
	k4	0.87	1.51	0.95
	k5	1.19	1.16	0.64
	R	0.86	1.32	0.37
2hTS (MPa)	k1	156.9	166	151.7
	k2	152.3	144.3	170.8
	k3	169.3	127.2	142.7
	k4	173.2	183.1	163.2
	k5	152.4	183.5	175.7
	R	20.9	56.3	33

4.3.2. Elastic Modulus

The data summarizing the elastic modulus of the straw-magnesium oxysulfide cement artificial board are presented in Table . Analysis of the results indicates that the hot-pressing temperature exerted the strongest influence on the elastic modulus, surpassing both the applied pressure and the processing time. The optimal manufacturing parameters were identified as combination A2B4C4. Specifically, a processing temperature of 120 °C, a pressure of 7.5 MPa, and a duration of 12 min collectively produced the maximum elastic modulus for the straw-based magnesium oxysulfide cement board.

4.3.3. Internal Bonding Strength

The internal bonding (IB) strength results for the straw-magnesium oxysulfide cement board are summarized in Table . Data analysis indicates that the hot-pressing temperature was the most influential parameter for IB strength, followed by processing time and applied pressure. The optimal manufacturing conditions, corresponding to combination A4B5C4, were identified as a temperature of 120 °C, a duration of 14 min, and a pressure of 12.5 MPa. Under these parameters, the manufactured board achieved its peak internal bonding strength.

4.3.4. Two-Hour Water Absorption Thickness Swelling Rate

Table presents the 2-h water absorption thickness swelling rates for the straw-magnesium oxysulfide cement board. Analysis of the data indicates that the hot-pressing temperature had the greatest effect on reducing swelling, with pressure and time being secondary and tertiary influencing factors, respectively. The optimal process parameters, corresponding to combination A2B3C3, were a temperature of 100 °C, a pressure of 10 MPa, and a duration of 8 min. Boards produced under these conditions exhibited minimal water absorption thickness swelling.

4.4. Effect of Hot-Pressing Time

Statistical analysis shows that the static bending intensity first increases and then decreases within the processing time range of 6 to 14 min, reaching its peak at 12 min (Figure a). This indicates that the optimal processing time for the composite board is 12 min, as prolonged processing leads to fiber degradation and a consequent reduction in strength. The variation trend of the elastic modulus is similar to that of the static bending strength, with both reaching their optimal values at 12 min (Figure b). This indicates that the rigidity of the sheet is optimal at this time, and excessive treatment will weaken its elastic recovery capacity. The internal bonding strength increases gradually with longer processing times (Figure c). This parameter reflects the bonding quality between the internal fibers and the magnesium oxysulfide matrix. A longer processing time facilitates the penetration and curing of the adhesive, thereby increasing the bonding strength. The change in the 2-h water absorption thickness swelling rate is relatively gradual (Figure d), indicating that treatment duration has a limited impact on the water resistance of the board.

6.

Material properties at different times,(a) Static bending strength vs time; (b) Elastic modulus vs time; (c) Internal bonding strength vs time; (d) 2-h water absorption thickness swelling rate vs time.

4.5. Effect of Hot-Pressing Temperature

The static bending strength increases rapidly from 60 to 120 °C, as the magnesium oxysulfide adhesive fully flows and penetrates the fibers, forming effective adhesive bonds (Figure a). The strength then decreases from 120 to 140 °C due to the thermal degradation of the fibers. The variation trends of the elastic modulus and internal bonding strength are consistent with those of the static bending strength (Figure b,c). However, when the temperature is too high, cracks occur due to excessively high vapor pressure, leading to a decline in the elastic modulus and internal bonding strength. At 100 °C, the adhesive reaches its peak degree of cross-linking, the matrix structure becomes the densest, and internal cracks are minimal. When the temperature exceeds 120 °C, it not only accelerates fiber degradation but also generates additional cracks due to excessive internal pressure, ultimately reducing the water resistance of the composite material (Figure d).

7.

Material properties at different temperatures, (a) static bending strength vs temperature; (b) elastic modulus vs temperature; (c) internal bonding strength vs temperature; (d) 2-h water absorption thickness swelling rate vs temperature.

4.6. Effect of Hot-Pressing Pressure

The static bending strength first increases and then decreases with increasing pressure, reaching its peak at 7.5 MPa (Figure a). When the pressure is lower than 7.5 MPa, insufficient pressure leads to inadequate fiber contact, reducing the effective wetting area of the adhesive at the interface and resulting in lower strength. The fiber interlocking state is optimal, and the static bending strength is highest when the pressure is 7.5 MPa. When the pressure rises to 10 −15 MPa, the fibers are crushed, and microcracks form in the adhesive layer, resulting in decreased strength. The variation trend of the elastic modulus is consistent with that of the static bending strength, first increasing and then decreasing (Figure b). When the pressure is too high, the fibers undergo buckling deformation, leading to a reduction in modulus. The internal bonding strength is lowest at 5 MPa, as the pressure is too low for the core layer adhesive to spread fully. It then gradually increases to 7.5 MPa, at which point the pressure promotes effective contact between the core layer and the adhesive layer (Figure c). When the pressure exceeds 7.5 MPa and then decreases again, excessively high pressure squeezes out the core layer adhesive, causing uneven distribution of the adhesive layer and reducing the bonding strength. The swelling rate of water absorption thickness changes relatively gradually with increasing pressure (Figure d), indicating that higher pressure has only a limited effect on improving the board’s water resistance.

8.

Material properties under different pressures, (a) static bending strength vs pressure; (b) elastic modulus vs pressure; (c) Internal bonding strength vs pressure; (d) 2-h water absorption thickness swelling rate vs pressure.

5. Conclusions

With the increasing emphasis on green initiatives and environmental protection, comprehensive utilization has become a trend in the treatment of agricultural residues such as straw. The scientific use of straw offers a practical solution to the challenges posed by random disposal and open-field burning in the country. This approach not only reduces emissions of carbon dioxide and nitrogen oxides but also contributes to ecological improvement, thereby promoting coordinated development between agriculture and the natural environment. In this study, straw-magnesium oxychloride cement boards were fabricated using a self-developed adhesive. Using an orthogonal experimental design, the optimal processing conditions were determined to be hot-pressing at 120 °C for 12 min under a pressure of 7.5 MPa, with a straw content of 55%. Under these conditions, the static bending strength of the pressed straw-magnesium oxysulfide cement board was 6.1 MPa. However, the waterproofing of pressed straw-based artificial boards still requires improvement. It is necessary to simplify the straw pretreatment process and enhance its wettability while preserving its esthetic appearance. Future research will focus on the application of modified straw adhesives in the production of pressed straw artificial boards.

The authors declare no competing financial interest.