Talc in wood-plastic composites

Talc is a multifunctional, inert mineral filler with the chemical formula Mg3Si4O10(OH)2. It is used as an additive, functional filler, or antifriction adjuvant in the production of polymer composites, construction materials, and refractory ceramics. Due to its composition of rock-forming oxides and crystalline structure, talc possesses a unique set of properties that influence the physical and chemical properties of WPC profiles.

One of the key components that improves the properties of WPC is talc—the softest natural mineral. Its use has a positive effect on the composites' performance:

- Reduced abrasive wear of equipment: Talc has a minimum hardness on the Mohs scale (1), significantly reducing wear on processing equipment components compared to other mineral fillers, such as calcite or mica. This extends the service life of equipment and reduces operating costs. Talc's lamellar structure increases the tensile and flexural modulus of polymers, enabling the production of lighter yet equally durable products by reducing their thickness.
- Talc's high thermal stability (decomposition temperature of 1500°C) reduces the coefficient of linear thermal expansion (CLTE) and polymer shrinkage, allowing for the preservation of shape and dimensional stability during the production of WPC profiles.
- Due to its natural hydrophobicity, talc filler helps reduce the permeability and water absorption of wood-filled composites.
- Talc's oil absorption capacity depends on its particle size distribution and can vary from 30 to 60 units, enabling the production of coatings with both matte and glossy surfaces.
- The combination of talc's high oil absorption capacity and low hydrophobicity improves component interactions and significantly impacts polymer viscosity.