Fluorine-free and durable hydrophobic coating made with corn straw-derived silane modified epoxy resin

Abstract

Hydrophobic materials have promising applications. However, fluorine present in hydrophobic materials can lead to health risks and environmental pollution. This study investigated an environmentally friendly route to produce fluorine-free hydrophobic coatings with good wear resistance. Wear-resistant hydrophobic coatings were prepared by introducing different ratios of spirocyclic alkoxysilane into the epoxy resin. Characterization by Fourier transform infrared spectroscopy, water contact angle measurement, scanning electron microscope, tape adhesion test, and abrasion testing showed that the multi-methyl group and double-ring rigid skeleton structure of spirocyclic alkoxysilane can remarkably improve the hydrophobic performance and wear resistance of the epoxy resin. The modified hydrophobic coatings can withstand more than 1600 instances of controlled rubbing. Furthermore, the maximum water contact angle can reach 110° after substantial abrasion. The novelty of the work is that the authors successfully synthesized spirocyclic alkoxysilane for the first-time using corn straw ash. The prepared spirocyclic alkoxysilane was then used as a modifier to prepare hydrophobic epoxy resin coating. This approach can broaden the utilization of corn straw ash. Therefore, this method can achieve a green and low-cost preparation of wear-resistant hydrophobic coatings without the introduction of fluorine.

Synthesis of silsesquioxanes with methacryloyloxy and phenyl groups using corn stover ash as the major precursor

“…Spirocyclic alkoxysilane was synthesized from corn stover ash using a reported method (Liu et al 2023). In brief, 500 g of corn stover ash was introduced into a 2-L threenecked flask.…”

“…Figure 1 shows the mass spectrum of spirocyclic alkoxysilane, the mass spectrum of the product synthesized from corn stover ash. Liu et al (2023). "Synthesis of silsesquioxanes," BioResources 18(2), 3827-3837.…”