柯汀,番茄皮的主要结构成分之一,是富含羟基化脂肪酸的蜡质生物聚合物。在这项研究中,从番茄皮中提取并分离出10,16-二羟基十六烷酸(10,16-diHHDA),并用于开发完全交联的聚酯,作为替代化石基金属保护涂层的潜在候选者。进行了初步筛选以选择基础配方,然后使用实验设计(DoE)作为方法来鉴定最佳组成以开发合适的涂层材料。含有10,16-diHHDA和其他生物炼制单体的不同配方,包括2,5-呋喃二甲酸,被考虑。为此,通过差示扫描量热法(DSC)和凝胶含量测量来表征所有聚酯以确定它们的Tg值和交联效率。在Tg值之间表现出最佳权衡的组合物,耐化学性,和在39至48重量%之间的足够高的10,16-diHHDA含量。%用于制备模型涂层,其特征在于评估其润湿性,划痕硬度,耐化学性,和对金属基材的附着力。这些聚酯涂层的Tg在45-55°C的范围内,水接触角约为100°的疏水行为,良好的耐溶剂性(>100MEK双摩擦),与钢的粘合强度高于2MPa。获得的结果证实了角质基树脂作为金属保护涂层的潜力,满足确保最终产品物理化学性能的要求,以及优化番茄皮等丰富的农业食品废物的价值。
Cutin, one of the main structural components of tomato peels, is a waxy biopolymer rich in hydroxylated fatty acids. In this study, 10,16-dihydroxyhexadecanoic acid (10,16-diHHDA) was extracted and isolated from tomato peels and exploited to develop fully crosslinked polyesters as potential candidates for replacing fossil-based metal protective coatings. A preliminary screening was conducted to select the base formulation, and then a design of experiments (DoE) was used as a methodology to identify the optimal composition to develop a suitable coating material. Different formulations containing 10,16-diHHDA and other biorefinery monomers, including 2,5-furandicarboxylic acid, were considered. To this end, all polyesters were characterized through differential scanning calorimetry (DSC) and gel content measurements to determine their Tg value and crosslinking efficiency. Compositions exhibiting the best trade-off between Tg value, chemical resistance, and sufficiently high 10,16-diHHDA content between 39 and 48 wt.% were used to prepare model coatings that were characterized for assessing their wettability, scratch hardness, chemical resistance, and adhesion to metal substrates. These polyester coatings showed a Tg in the range of 45-55 °C, a hydrophobic behavior with a water contact angle of around 100°, a good solvent resistance (>100 MEK double rubs), and an adhesion strength to steel higher than 2 MPa. The results obtained confirmed the potential of cutin-based resins as coatings for metal protection, meeting the requirements for ensuring physicochemical properties of the final product, as well as for optimizing the valorization of such an abundant agri-food waste as tomato peels.