Abstract:
In this work, four thymol-based benzoxazines were synthesized using four primary amines with different chain lengths, namely methylamine, ethylamine, 1-propylamine, and 1-butylamine, which are then named T-m, T-e, T-p, and T-b, respectively. The optical properties of the synthesized thymol-based benzoxazines were examined via the photoluminescent study of their solutions in acetone. The results show that all the prepared benzoxazines emitted blue light with the maximum wavelengths from 425 to 450 nm when irradiated by the excitation wavelengths from 275 to 315 nm. The maximum excitation wavelengths are found to be 275 nm. The polymerization of the thymol-based benzoxazines is triggered by heat treatments with different conditions (160, 180, and 200 °C for 1 h). According to the FTIR results, the heat-curing process introduces a presence of the OH peak, of which intensity increases as the curing temperature increases. Thermal decompositions of thymol-based benzoxazines regarding TGA analyses reveal the enhancement of thermal stability of the benzoxazines with respect to the N-substituent chain length, as significantly observed the change in the first thermal decomposition at temperature ranged from 253 to 260 °C. Synthesized benzoxazine derivatives are further employed to coat the substrate, e.g., the glass slides. The investigation of the water contact angle shows that the coating of the benzoxazines onto the surface improves the hydrophobicity of the substrate, resulting in the enlargement of the contact angle from 25.5° to 93.3°. Moreover, the anticorrosion performance of the polybenzoxazine coatings is examined using potentiodynamic polarization techniques. The results illustrate the anticorrosion efficiency of the thymol-based polybenzoxazine up to 99.99%. Both hydrophobic and electrochemical studies suggest the feasibility for employing benzoxazines in anticorrosion coating applications.
摘要:
在这项工作中,使用四种不同链长的伯胺合成了四种百里酚基苯并恶嗪,即甲胺,乙胺,1-丙胺,和1-丁胺,然后被命名为T-m,T-e,T-p,还有T-b,分别。通过光致发光研究其在丙酮中的溶液,检查了合成的百里酚基苯并恶嗪的光学性质。结果表明,当被275至315nm的激发波长照射时,所有制备的苯并恶嗪发出的最大波长为425至450nm的蓝光。发现最大激发波长为275nm。百里酚基苯并恶嗪的聚合是通过在不同条件下(160、180和200°C持续1小时)的热处理触发的。根据FTIR结果,热固化过程引入了OH峰的存在,其强度随着固化温度的增加而增加。关于TGA分析的百里酚基苯并恶嗪的热分解揭示了苯并恶嗪相对于N-取代基链长度的热稳定性的增强,如明显观察到的,在253至260°C的温度范围内的第一次热分解的变化。合成的苯并恶嗪衍生物进一步用于涂覆基材,例如,玻璃幻灯片。水接触角的研究表明,苯并恶嗪在表面的涂层改善了基材的疏水性,导致接触角从25.5°扩大到93.3°。此外,使用动电位极化技术检查了聚苯并恶嗪涂层的防腐蚀性能。结果表明,百里酚基聚苯并恶嗪的防腐效率高达99.99%。疏水和电化学研究均表明在防腐蚀涂层应用中使用苯并恶嗪的可行性。