自适应可逆温致变色复配物的变色与老化失效机制研究

Study on Thermochromic and Aging Failure Mechanism of Adaptive Reversible Thermochromic Complex

以荧烷染料为隐色剂,双酚A为显色剂,十四醇/十六醇/十八醇混合溶液为溶剂,组成3组分反应体系,采用一定工艺制备了自适应可逆温致变色复配物。通过核磁图谱测试、XRD、红外光谱分析与气相色谱分析分别测定了试验原料与变色复配物老化失效前后的本征参数,研究了复配物的变色与老化失效机制。实验结果表明:自适应可逆温致变色复配物变色机理为双酚A与荧烷染料之间的电子得失,双酚A通过攻击具有亲电性质的荧烷染料中心C原子,导致其内酯环断裂,形成具有发色性的亚稳态产物,此外,共轭发色体的不稳定性也是复配物具备变色可逆性的关键因素。而其变色失效原理是荧烷染料,在紫外光激发下,内酯环和苯环与中心碳原子之间的C—C键发生了断裂,脱出了小分子产物,造成隐色剂失去与显色剂反应生成共轭发色体的能力,从而老化失效。

The self-adaptive reversible thermochromic complex was prepared by using fluorane dye as colorant, bisphenol A as chromogenic agent and tetradecanol/hexadecanol/octadecanol mixed solution as solvent. By means of XRD, IR, 1 H NMR and gas phase analysis, the intrinsic parameters before and after aging of the complexe were determined, and the discoloration and aging failure mechanism of the complex were studied. It was concluded that the discoloration mechanism of the self-adaptive reversible thermochromic complex is the electronic gain and loss between the chromogenic agent bisphenol A and the fluorescent agent fluorane dye. Bisphenol A attacks the C atom of the fluorane dye center which has the electrophilic property, resulting in the lactone ring breaking and forming the metastable product with chromogenic property. In addition, the instability of conjugated chromophore is also the key factor of color changing inversion of the complex. The mechanism of discoloration failure is that the C—C bond between lactone ring, benzene ring and central carbon atom breaks under UV excitation, and the small molecule products are removed, resulting in the loss of the cryptochrome to react with the developer to form conjugated chromophore, which leads to aging failure.