Mechanical, adhesion and corrosive properties of unsaturated polyester-graphene coating treated with silane coupling agent on metal substrate

Abstract

Graphene treated with silane based unsaturated polyester resin was successfully prepared for primer coatings application sonication process. Corrosion has been a major issue worldwide due to its failure building structure and high maintenance. The usage of Unsaturated Polyester (UPE) alone is insufficient to inhibit the corrosion. Hence, primer coatings using UPE filled graphene (GR) been developed as a significant step to preserve the steel structures. The objectives of this study was to investigate the mechanical, adhesion and corrosive properties of various graphene loading (0, 2, 4, 6 wt%) filled unsaturated polyester reinforced on metal substrate and determine the effect of silane treatment on graphene reinforcement in unsaturated polyester-graphene coating for primer application with different silane loading (1, 3, 5 wt%) and GR loading at 4%. Mechanical properties testing has been conducted by hardness test, while as for adhesion properties testing through pull out test and contact angle measurement. Immersion test and Tafel Polarization method was conducted to determine the corrosive properties of coating. For hardness testing, UPE- GR/GPS regardless of its loading have the higher value of scratch resistance at 5H. While as for pull out test, UPE/GR and UPE/GR- GPS show the same scale which is scale 5. Hence, it shows that properties of graphene itself are higher in strength since it does not affect when the pull-out test was carried out. 3 % of UPE/GR-GPS gives high value for advancing which is 153.544° and receding is at 127.254° compared to others samples. Other than that, immersion test in two medium which is NaCl and seawater solution show an improvement of corrosion when addition of silane was implemented on graphene due to the presence of corrode can be seen at day 6 compare to other samples that started to corrode at day 3. As for Tafel polarization, 3 % UPE/GR-GPS has the highest polarization resistance which is 185.56 n and has the lowest for corrosion rate which is 0.148 mmpy. Overall, the incorporation of graphene/silane into composite improve the mechanical, adhesion and corrosive properties and the optimum coating was found at 3 % UPE/GR-GPS.