橡胶籽油基温致变色手印薄膜研究

Preparation of Thermochromic Fingerprint Film Based on Rubber Seed Oil

摘要: 以橡胶籽油为生物基原料，制备橡胶籽油基聚氨酯丙烯酸酯(PUA)预聚体，并构建聚脲包覆温致变色微胶囊，进一步制备具有可逆温致变色性能的光固化薄膜材料。采用傅里叶红外光谱(FT-IR)、核磁共振氢谱(¹H NMR)、扫描电子显微镜(SEM)及实时红外技术对材料结构、微观形貌及光固化动力学进行表征。研究微胶囊粒径及添加量对树脂固化性能、热致变色性能及手印采集效果的影响。结果表明：所制备温致变色薄膜在40℃~45℃范围内具有良好的可逆变色特性，变色响应时间低于3 s；微胶囊化处理显著提高了复配物循环稳定性，20次热循环后颜色衰减率低于8%；当微胶囊添加量为15 wt%、平均粒径为3.2 μm时，所得薄膜兼具较高双键转化率(86.4%)与优良手印成像效果，能够清晰呈现乳突纹线及细节特征。研究表明，橡胶籽油基温致变色PUA薄膜在绿色生物基功能材料及刑事科学技术领域具有良好的应用前景。

Abstract: A bio-based polyurethane acrylate (PUA) prepolymer derived from rubber seed oil was synthesized, and thermochromic microcapsules coated with polyurea were prepared to fabricate UV-curable thermochromic films. Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (¹H NMR), scanning electron microscopy (SEM), and real-time infrared spectroscopy were employed to characterize the structure, morphology, and photocuring kinetics of the materials. The effects of microcapsule size and content on curing behavior, thermochromic performance, and fingerprint imaging quality were investigated. The results showed that the prepared films exhibited reversible thermochromic behavior within 40˚C~45˚C, with a response time below 3 s. Microencapsulation significantly improved thermal cycling stability, and the color attenuation rate remained below 8% after 20 cycles. When the microcapsule content was 15 wt% and the average particle size was 3.2 μm, the film achieved a high double-bond conversion rate of 86.4% and excellent fingerprint imaging quality. Continuous ridge structures and clear minutiae details were successfully obtained. The study demonstrates the promising application of rubber seed oil-based thermochromic PUA films in sustainable functional materials and forensic science.