Micó-Vicent Bàrbara, Ramos Marina, Luzi Francesca, Dominici Franco, Viqueira Valentín, Torre Luigi, Jiménez Alfonso, Puglia Debora, Garrigós María Carmen
Colour and Vision Group, University of Alicante, San Vicente del Raspeig, ES-03690 Alicante, Spain.
Department of Appl. Stat. & Operat. Research, & Qual., Universitat Politècnica de València, ES-03801 Valencia, Spain.
Polymers (Basel). 2020 Oct 28;12(11):2508. doi: 10.3390/polym12112508.
Natural dyes obtained from agro-food waste can be considered promising substitutes of synthetic dyes to be used in several applications. With this aim, in the present work, we studied the use of chlorophyll dye (CD) extracted from broccoli waste to obtain hybrid nanopigments based on calcined hydrotalcite (HT) and montmorillonite (MMT) nanoclays. The synthesized chlorophyll hybrid nanopigments (CDNPs), optimized by using statistical designed experiments, were melt-extruded with a polyester-based matrix (INZEA) at 7 wt% loading. Mechanical, thermal, structural, morphological and colour properties of the obtained bionanocomposites were evaluated. The obtained results evidenced that the maximum CD adsorption into HT was obtained when adding 5 wt% of surfactant (sodium dodecyl sulphate) without using any biomordant and coupling agent, while the optimal conditions for MMT were achieved without adding any of the studied modifiers. In both cases, an improvement in CD thermal stability was observed by its incorporation in the nanoclays, able to protect chlorophyll degradation. The addition of MMT to INZEA resulted in large ΔE* values compared to HT incorporation, showing bionanocomposite green/yellow tones as a consequence of the CDNPs addition. The results obtained by XRD and TEM revealed a partially intercalated/exfoliated structure for INZEA-based bionanocomposites, due to the presence of an inorganic filler in the formulation of the commercial product, which was also confirmed by TGA analysis. CDNPs showed a reinforcement effect due to the presence of the hybrid nanopigments and up to 26% improvement in Young's modulus compared to neat INZEA. Finally, the incorporation of CDNPs induced a decrease in thermal stability as well as limited effect in the melting/crystallization behaviour of the INZEA matrix. The obtained results showed the potential use of green natural dyes from broccoli wastes, adsorbed into nanoclays, for the development of naturally coloured bionanocomposites.
从农业食品废料中获得的天然染料可被视为合成染料的有前景的替代品，可用于多种应用。出于这个目的，在本研究中，我们研究了从西兰花废料中提取的叶绿素染料（CD）用于制备基于煅烧水滑石（HT）和蒙脱石（MMT）纳米粘土的混合纳米颜料。通过统计设计实验优化合成的叶绿素混合纳米颜料（CDNP），以7 wt% 的负载量与聚酯基基质（INZEA）进行熔融挤出。对所得生物纳米复合材料的力学、热、结构、形态和颜色性能进行了评估。所得结果表明，在不使用任何生物媒染剂和偶联剂的情况下，添加5 wt% 的表面活性剂（十二烷基硫酸钠）时，HT对CD的吸附量最大，而MMT的最佳条件是在不添加任何所研究的改性剂的情况下实现的。在这两种情况下，通过将CD掺入纳米粘土中，观察到CD的热稳定性有所提高，能够保护叶绿素降解。与掺入HT相比，向INZEA中添加MMT导致更大的ΔE*值，由于添加了CDNP，生物纳米复合材料呈现出绿色/黄色调。XRD和TEM获得的结果表明，基于INZEA的生物纳米复合材料具有部分插层/剥离结构，这是由于商业产品配方中存在无机填料，TGA分析也证实了这一点。由于混合纳米颜料的存在，CDNP显示出增强效果，与纯INZEA相比，杨氏模量提高了26%。最后，CDNP的掺入导致热稳定性降低，并且对INZEA基质的熔融/结晶行为影响有限。所得结果表明，吸附在纳米粘土中的西兰花废料中的绿色天然染料在开发天然有色生物纳米复合材料方面具有潜在用途。
