Redispersible polymer powder is not simply an additive in dry mortar, but rather forms an organic-inorganic composite bonding system together with inorganic cementitious materials such as cement, achieving a performance leap of "1+1>2". Its working principle is mainly reflected in:
Physical effect:
Improve cohesion and adhesion: The adhesive powder redisperses into an emulsion upon contact with water, and then reforms into a film in the mortar, firmly bonding cement hydration products, aggregates, etc. together, significantly improving the material's cohesive strength and adhesion to various substrates.
Formation of polymer network: When the dosage is sufficient (usually >2%), the polymer film forms a continuous and elastic network structure in the mortar, which interpenetrates with the rigid cement stone skeleton to form an interpenetrating network structure.
Chemical and morphological effects:
Bridging and filling: Polymer films can bridge microcracks and prevent their propagation. At the same time, they fill pores, making the structure denser.
Lowering the modulus of elasticity imparts flexibility to the mortar, improves its resistance to deformation, and reduces stress cracking caused by shrinkage, temperature differences, and base layer displacement.
The specific manifestations of performance improvement
Mechanical properties: Improves flexural strength, impact resistance, abrasion resistance, and flexibility (bending).
Bonding performance: Significantly improves the bonding strength with various substrates (concrete, brick, EPS/XPS board, etc.).
Durability: Reduces water absorption and improves impermeability, freeze-thaw resistance, and weather resistance.
Workability: Improves the workability, water retention (synergistic with cellulose ethers), and anti-slip properties of mortar.
Volume stability: Reduces shrinkage and lowers the risk of cracking.
Key Points and Suggestions for Choosing Dimensions
Choose according to application: For high flexibility requirements, choose low Tg (<5℃) adhesive powder. For high strength/hardness requirements, choose higher Tg (>10℃) adhesive powder. Choose products according to quality, pay attention to ash content, and be wary of low-priced "resin adhesive powder/composite adhesive powder". Systematic formulation design: Adhesive powder must be designed in synergy with suitable ash-sand ratio, high-quality cellulose ethers, and other components to balance performance, workability, and cost. Avoid pursuing high addition levels of any single component.
Redispersible polymer powder is the core material for achieving high performance in dry powder mortar. Correct selection and application, combined with scientific dosage and systematic formulation design, ultimately achieve comprehensive optimization of the mortar's adhesion, flexibility, durability, and workability.
Post time: Dec-19-2025