Development of tertiary butyl hydroquinone based polybenzoxazine for effective anti-microbial and anti-corrosion coating applications

The work presents a new type of polybenzoxazines synthesised using tertiary butyl hydroquinone (THQ) with aromatic and fluorinated mono functional amines such as aniline (a), ethynylaniline (ea), cyanoaniline (ca), fluoroaniline (fa), trifluoromethylaniline (tfma) and 4-fluorotrifluoromethylaniline (4ftma). The structure of the benzoxazines were elucidated using spectroscopyic technique. The curing behaviour, thermal stability of the THQ polybenzoxazines were studied in order to assess their performance in high themperature environments. Among the six polybenzoxazines synthesized, the tert-butyl hydroquinone with cyanoaniline based polybenzoxazine shows the exceptional thermal stability with higher residual value of 60 % and higher degradation temperature of 553 °C. The moisture resistance behaviour of the synthesized THQ polybenzoxazines have been studied and all the THQ polybenzoxazines possess excellent hydrophobicity. The synthesized THQ polybenzoxazines were tested for their surface protection efficiency as anti-corrosive coatings on mild steel surfaces. The poly(THQ-4ftma) polybenzoxazine coating exhibits excellent corrosion resistant behaviour with efficiency of 99.99 %. All the six THQ polybenzoxazine coated mild steel specimen shows better corrosion resistant behaviour than that of the uncoated mild steel. In addition to the above, THQ benzoxazines were checked for their antibacterial activity (against S. aureus and E.coli ) was checked and inhibition zone was observed at greater than 25 mm. The results obtained from different studies indicate that the tert-butyl hydroquinone based benzoxazines can be effectively used as a multifunctional coatings under high thermal environment and protection against microbes including adverse corrosive environment. • New type of tertiary butyl hydroquinone (THQ) based polybenzoxazines synthesized and structure have been elucidated. • The THQ polybenzoxazines possess excellent hydrophobicity with water contact angle values above 144°. • The poly(THQ-4ftma) polybenzoxazine coating exhibits excellent corrosion resistant behaviour with efficiency of 99.99 %. • The synthesized THQ polybenzoxazines have better surface efficiency as anti-microbial. • The tert-butyl hydroquinone based benzoxazines can be effectively used as a multifunctional coatings.