Thermal and Photochemical Crosslinking of Paper Fibers for Generation of Paper Substrates Providing a High Wet Strength and Multiple Chemical Fucntions

如果纸与水接触，机械强度会大大降低，在某些情况下只能达到初始强度的几个百分点。出于这个原因，当生产用于可能被弄湿的纸张时，需要添加大量的所谓的湿强剂--主要是阳离子聚合物。这些湿强剂附着在纸纤维上，部分化学交联，增强纸纤维及其粘合力，尽管这种增强机理的细节尚未阐明到最后的细节。然而，就其环境行为而言，常用的湿强剂并不是没有问题。在目前的供资阶段，可以使用C、H插入交联法(CHIC法)生产湿强度比未改性纸好50倍的纸。为此，已经开发或进一步开发了光化学和热诱导交联法。为进一步阐明纸纤维的增强机理奠定了基础。继续这项研究的目的是为了进一步研究功能化纸张的湿强发展。重点将放在进一步提高我们对湿纸增强机理的理解的研究上。为此，将对论文中聚合物的分布进行更详细的分析，并继续进行单独的纤维实验。为了研究聚合物固定化(CHIC方法)，纤维素纤维的拓扑结构将借助含有碳水化合物结合基序的特定结合酶进行染色。此外，还将改变湿强剂的化学结构，使纸张即使在低于100°C的温度下也能快速粘合和增强，从而使纸张不必完全干燥即可完成湿强度整理，这将大大节省能源。此外，这一概念将得到扩展，即使是纸纤维和不完整的纸张也可以进行修改，所使用的聚合物浓度可以显著降低。此外，这一概念将得到扩展，以便在纸张生产之前就可以对纸张纤维进行改性，并显著降低聚合物的使用浓度。此外，还将研究多功能湿强剂设计的第一个概念，其中湿强度的提高与进一步的功能相结合。

If paper comes into contact with water, the mechanical strength decreases considerably and under certain circumstances only reaches a few percent of the initial strength. For this reason, when producing papers that are intended for use in which they can get wet, significant amounts of a so-called wet strength agents - mostly cationic polymers - are added. These wet strength agents are attached to paper fibers, are partially chemically cross-linked and strengthen the paper fibers and their cohesion, although the details of this reinforcement mechanism have not been clarified down to the last detail. The commonly used wet strength agents are, however, not without problems in terms of their environmental behavior. In the current funding phase, it has been possible to use C,H insertion crosslinking processes (CHic process) to generate papers that have a wet strength that is 50 times better than that of unmodified paper. For this purpose, photochemical and thermally induced crosslinking processes have been developed or further developed. Furthermore, the first results to elucidate the reinforcement mechanism of the paper fibers could be obtained. The aim of the continuation of the research project is to further continue our investigations into wet-strength development of functionalized papers. The focus will be on studies that will further improve our understanding of the reinforcement mechanism in wet papers. For this purpose, the distribution of the polymers in the paper is to be analyzed in more detail and individual fiber experiments are to be continued. To investigate the polymer immobilization (CHic method), the topology of the cellulose fibers is to be stained with the help of specific binding enzymes that contain the carbohydrate binding motif. Furthermore, changes are to be made in the chemical structure of the wet strength agent, which allow rapid bonding and reinforcement of the paper even at temperatures below 100 ° C, so that the papers do not have to be completely dry for the wet-strength finish, which would result in considerable energy savings. In addition, the concept is to be expanded so that even paper fibers and incomplete papers can be modified and the concentration of polymers used can be significantly reduced. In addition, the concept is to be expanded so that paper fibers can already be modified before paper production and the use concentration of the polymers can be significantly reduced. Furthermore, first concepts for the design of multifunctional wet strength agents will be investigated, in which the improvement of wet strength is combined with further functionalities.