Polymer composites and resins — roles of catalysts and fillers Which of the following statements about resin systems and fillers in building materials is correct?

Introduction / Context:
Polymer matrix composites and resin-bonded products are widely used in construction (laminates, adhesives, flooring). Understanding additives—catalysts, fillers, and fibers—helps explain performance and selection.

Given Data / Assumptions:

• Curing of thermoset resins requires initiators/catalysts or hardeners.
• Fillers may be particulate (chalk, silica, alumina) or fibrous (glass, asbestos alternatives, cellulose).
• Performance targets include strength, hardness, thermal resistance, and cost control.

Concept / Approach:
Catalysts/hardeners accelerate crosslinking, enabling practical setting times. Inert particulate fillers improve hardness, stiffness, wear, and reduce shrinkage and cost. Fibrous fillers reinforce the matrix, enhancing mechanical and thermal performance by bridging cracks and impeding heat flow.

Step-by-Step Solution:

Verification / Alternative check:
Manufacturers’ data sheets for polyester, epoxy, and phenolic systems confirm the roles of peroxides/amines (catalysts), mineral fillers, and fibers (glass, aramid) in tailoring properties.

Why Other Options Are Wrong:

• Since A–C are valid, the comprehensive answer is “All of the above.”

Common Pitfalls:
Overusing catalysts can cause runaway cures or brittleness; poorly dispersed fillers can reduce strength; fibers require correct orientation and wet-out for benefits.

Final Answer: