Well-cured silicone/halloysite nanotubes nanocomposite coatings

Abstract

Silicone elastomer coatings are known for their softness and high elongation properties, but not for faithful service over time because of their inadequate adhesion, thermal, and mechanical properties. Addition of nanofillers to silicone would be the solution to such long-standing shortcomings, but yet there is a little guarantee of success because of silicone crosslinking being significantly hindered by filler incorporation. In this work, well-cured 3D silicone networks are formed by peroxide curing in the presence of pristine and silane-functionalized halloysite nanotubes (HNTs). Nanofillers are incorporated into silicone at different loadings and the curing potential of the resulting nanocomposite coatings are evaluated by dimensionless indexes of T* and ΔH* calculated from nonisothermal differential scanning calorimetry. Regardless of the content and surface chemistry of the HNTs, silicone nanocomposite was outstandingly cured by peroxide thanks to reactive surface of nanofillers. Overall, ΔH* value of ≈ 2 was indicative of a two-fold rise in the amount of heat release in silicone nanocomposites whatever heating rate. Moreover, T* values obtained were slightly lower than 1, a signature of an unhindered curing. The excellence of facilitated crosslinking brought about by the use of HNTs was featured by an improved polymer-filler interaction, which seems promising for coating applications. © 2019 Elsevier B.V.