Gypsum (CaSO₄·2H₂O) is a commonly used construction and industrial material, and its applications include building plaster, gypsum board, decorative plaster, etc. However, gypsum itself has some defects, such as low mechanical strength, insufficient toughness, and reduced strength after absorbing water. These problems limit the application range and service life of gypsum products. In order to improve these shortcomings, cellulose additives are often added to gypsum-based products. The addition of cellulose can significantly improve the performance of gypsum products, thereby enhancing their market competitiveness.
1. Improve work performance
Rheology Optimization
Gypsum needs good fluidity and workability during use. Cellulose additives can significantly improve the rheological properties of gypsum slurry. Cellulose expands in water to form a high-viscosity solution, which can increase the consistency of the gypsum slurry and improve its water retention capacity, thus delaying the hydration rate of the gypsum and giving the slurry a better construction and operability time. This characteristic is particularly important for gypsum spraying and pouring processes, as it helps control the fluidity of the slurry, avoid segregation and bleeding, and improve construction quality.
Enhanced water retention
Cellulose can significantly improve the water retention of gypsum slurry. Gypsum requires a certain amount of water to complete the hardening process during the hydration process. Good water retention can prevent water from evaporating too quickly during the hardening process, thereby ensuring sufficient hydration of the gypsum and improving its final strength. Cellulose forms a protective colloid that evenly distributes water around the gypsum particles, preventing uneven hardening caused by rapid water loss.
Anti-sag ability
In gypsum coating applications, sag resistance is an important indicator. The addition of cellulose can increase the viscosity of the gypsum slurry, allowing it to better adhere to the surface of the substrate during the construction process, reducing sagging due to gravity, and ensuring the uniformity and thickness consistency of the coating.
2. Enhance mechanical properties
Improved crack resistance
Cellulose fibers can significantly improve the crack resistance of gypsum-based materials. Gypsum products will shrink in volume during the hardening process, resulting in increased internal stress and easy formation of cracks. Cellulose fibers can form a three-dimensional network structure in the gypsum matrix, disperse stress, hinder the expansion of cracks, thereby improving the material’s crack resistance. This plays an important role in improving the service life of gypsum boards, decorative plaster and other products.
Increase resilience
Cellulose fibers can enhance the toughness of gypsum products and reduce brittleness. The gypsum material itself is brittle and prone to breakage when impacted or bent. The addition of cellulose fibers can provide additional toughness, allowing the material to have better deformation ability when subjected to stress and reduce brittle failure. This characteristic is particularly important in gypsum board and gypsum decorative products, because these products may be impacted by external forces during use.
Improve bending strength
Cellulose fibers also have a significant impact on the flexural strength of gypsum products. Cellulose fibers can form a reinforcing structure in the gypsum matrix and increase its flexural strength. This is particularly beneficial for flexural components such as gypsum board, as the increased flexural strength increases the load-bearing capacity and service life of the board.
3. Improve durability
Enhanced water resistance
The addition of cellulose can improve the water resistance of gypsum-based materials. Gypsum materials will soften after absorbing water and their strength will decrease, thus affecting their service life. Cellulose can form a protective film on the surface of the material to reduce the penetration of moisture, thereby improving the material’s water resistance. Improved water resistance can effectively extend the service life of gypsum products in humid environments and reduce performance degradation caused by water absorption and softening.
Prevent segregation
Cellulose prevents segregation during the manufacture of gypsum-based materials. Cellulose can stabilize suspended particles in gypsum slurry, preventing heavy particles from sinking and light particles from floating up, thereby ensuring the uniformity of the material. This is of great significance in improving the quality and consistency of plaster products.
Freeze and thaw resistance
The addition of cellulose can also improve the freeze-thaw resistance of gypsum materials. In cold regions, gypsum products may undergo repeated freeze-thaw cycles, causing damage to the material. Cellulose can reduce the internal stress generated during the freezing and thawing process and improve the durability of the material through its water retention and reinforcing effects.
4. Environmental protection and sustainability
Renewability
Cellulose is a natural, renewable resource extracted from plants that is environmentally friendly and sustainable. Using cellulose as an additive to gypsum-based materials not only meets environmental requirements, but also reduces dependence on non-renewable resources.
Biodegradability
Cellulose has good biodegradability, which means that after the gypsum products are discarded, cellulose can be degraded naturally without causing pollution to the environment. This has obvious environmental advantages compared with some synthetic fibers.
5. Diversified applications
Suitable for a variety of gypsum products
The versatile properties of cellulose make it suitable for use in a variety of gypsum products, including drywall, decorative plaster, plaster coatings, and more. Different types of cellulose derivatives (such as hydroxypropyl methyl cellulose, carboxymethyl cellulose, etc.) can be selected and formulated according to specific application requirements to achieve the best modification effect.
Adapt to different construction conditions
Cellulose additives show good adaptability under different construction conditions. For example, cellulose can still effectively improve the construction performance of gypsum slurry in high or low temperature environments. This property allows gypsum-based products to exhibit stable performance in a variety of climatic conditions.
The use of cellulose in gypsum-based products significantly enhances the overall quality of gypsum-based products by improving workability, enhancing mechanical properties, increasing durability and providing environmental benefits. These modification effects enable gypsum products to meet higher construction and decoration requirements and expand their application scope. With the development of building materials technology, the application of cellulose and its derivatives in gypsum-based products will become more extensive and in-depth, continuing to provide high-quality, environmentally friendly solutions to the construction industry.
Post time: Feb-17-2025