Robust and flexible transparent protective film
An ambient-curable hybrid resin (ACHR) terminated with trimethoxysilane functional groups, synthesised through a simple ring-opening reaction between 3-glycidyloxypropyltrimethoxysilane (KH560) and 4,4′-methylenebis (cyclohexylamine) (PACM), was applied to the surface of a transparent organic polymer to produce a robust, flexible, and transparent protective hybrid film, moisture cured at room temperature.
Superior resistance to bending and scratching
The structure, morphology, and optical, mechanical, and thermal properties of the obtained hybrid film were evaluated. The hybrid film allowed the transmittance of more than 87% of visible light (at 600 nm), maintaining almost the same high transparency as bare PET film. The unique flexible segments and rigid segments in the inorganic–organic hybrid structure of the film realised superior resistance to bending and scratching. The hybrid film-coated PET demonstrated excellent flexibility, with an extremely low bending radius, illustrated by wrapping around a 1-mm mandrel bar without cracking.
In addition, the hybrid film exhibited superior pencil hardness (of 2H) and excellent wear durability, i.e., no scratching after being subjected to 200 abrasion cycles using steel wool under a 19.6 kPa load. The robust, flexible, and transparent protective film developed here, and its simple and efficient preparation method, should have extensive application prospects.
The study has been published in Journal of Coatings Technology and Research, Volume 18, 2021.