The influence of talc powder on the elastic elongation and tensile strength of waterproof coatings shows a similar trend: with the increase of fillers, the elastic elongation and tensile strength of waterproof coatings increase at first, then decrease continuously, and an optimum value appears in the middle of Haicheng talc powder.

Considering from the molecular point of view, when the amount of talc powder is very small, the particles without talc powder are dispersed to the middle of the macromolecular chain, so the attraction between the macromolecular chains cannot be reduced. The macromolecular chains are difficult to move, resulting in a smaller elastic elongation of waterproof coatings. With the increase of the amount of talc powder, the small particles are continuously filled between the macromolecular chains. The elastic elongation increases when the chain motion is strengthened.

When the inorganic small particles of talc powder fill the gap between macromolecular chains, the curing system of waterproof coatings has the least defects, and the tensile strength and elongation of waterproof coatings reach an optimal value.