Pulidori Elena, Duce Celia, Bramanti Emilia, Ciccone Lidia, Cipolletta Brunella, Tani Gloria, Ioio Laura Dello, Birolo Leila, Bonaduce Ilaria
Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124, Pisa, Italy.
Center for Instrument Sharing of the University of Pisa (CISUP), University of Pisa, 56126, Pisa, Italy.
Sci Rep. 2025 Jul 2;15(1):23022. doi: 10.1038/s41598-025-04910-8.
Animal glues have been used since antiquity, but their popularity decreased in the twentieth century with the rise of synthetic adhesives. Currently they are primarily used in restoration of works of art. This study focuses on animal glue samples derived from bone and hide tissues used mainly for veiling and carpentry applications, examining their secondary structure, thermal and rheological properties, to shed light into their adhesive behaviour. Thermogravimetric analysis and differential scanning calorimetry highlight differences between hide and bone glues, showing that the latter are more hydrolysed. The calorimetric curves show varying values of denaturation enthalpy thus indicating a varying degree of gelatine renaturation. Additionally, the calorimetric analysis demonstrates the physical ageing of the glue samples, which is known to play a key role in maintaining their adhesive properties under specific storage conditions. The rheological data provide fundamental information on properties which are relevant for the use of animal glues as adhesives in various applications. XRD data suggest a low structural order in the samples investigated, where the amorphous component complicates the univocal interpretation of the spectra. FTIR reveal a relatively high content of β-structures in all commercial glue samples, as well as gelatine and collagen standards. Moreover, spectra of the glue films dried for 1 week show that the β-structures are recovered following dissolution in water and application. Therefore, β-structures seem crucial to explain the structure-dependent mechanical properties observed.
动物胶自古以来就被使用，但随着合成胶粘剂的兴起，它们在20世纪的受欢迎程度有所下降。目前，它们主要用于艺术品修复。本研究聚焦于主要用于裱糊和木工应用的源自骨组织和皮组织的动物胶样品，研究其二级结构、热性能和流变性能，以深入了解它们的粘合行为。热重分析和差示扫描量热法突出了皮胶和骨胶之间的差异，表明后者水解程度更高。量热曲线显示变性焓值各不相同，从而表明明胶复性程度不同。此外，量热分析证明了胶样品的物理老化，已知物理老化在特定储存条件下维持其粘合性能方面起着关键作用。流变学数据提供了与动物胶在各种应用中用作胶粘剂相关的性能的基本信息。X射线衍射数据表明所研究的样品结构有序度较低，其中无定形成分使光谱的明确解释变得复杂。傅里叶变换红外光谱显示，所有商业胶样品以及明胶和胶原蛋白标准品中β结构的含量相对较高。此外，干燥1周的胶膜光谱表明，β结构在溶解于水并应用后得以恢复。因此，β结构似乎对于解释所观察到的与结构相关的机械性能至关重要。
