Affiliation:
1. Ernst-Berl-Institut Macromolecular and Paper Chemistry, Technical University Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
Abstract
With the overarching aim for the development of sustainable, nontoxic wet strength agents for paper, a novel polymer gel system based on oxidized hydroxypropyl cellulose (keto-HPC) cross-linked with polyamines was investigated in detail to gain a deeper insight into the wet strength mechanism. When applied to paper, this wet strength system significantly increases the relative wet strength by using only low amounts of polymer, and it is therefore comparable with established wet strength agents based on fossil resources, such as polyamidoamine epichlorohydrin resins. With the help of ultrasonic treatment, keto-HPC was degraded with respect to its molecular weight and further cross-linked in paper using polymeric amine-reactive counterparts. The resulting polymer-cross-linked paper mechanical properties were analyzed with respect to the dry and wet tensile strength, respectively. In addition, we analyzed the polymer distribution using fluorescence confocal laser scanning microscopy (CLSM). If high-molecular-weight samples are being used for cross-linking, we do find accumulation of the polymer mainly on the surface of the fibers and at fiber crossing points, accompanied with enhancing strong effects on paper’s wet tensile strength. In contrast, if low-molecular-weight (i.e., degraded) keto-HPC is being applied, the macromolecules are capable of entering the inner porous structure of the paper fibers, and almost no accumulation at the fiber crossing points is observed, which also results in a lowered wet paper tensile strength, respectively. This insight into wet strength mechanisms of the keto-HPC/polyamine system can thus lead to new opportunities for the development of alternative biobased wet strength agents where molecular weight dependence of the wet tensile properties allows for a fine tuning of mechanical properties in the wet state.
Funder
German Research Council, DFG
Subject
Polymers and Plastics,Organic Chemistry,Biomaterials,Bioengineering
Reference44 articles.
1. Biopolymer Films and Coatings in Packaging Applications—A Review of Recent Developments;Vartiainen;MSA,2014
2. Biopolymer Coatings on Paper Packaging Materials;Khwaldia;Compr. Rev. Food Sci. Food Saf.,2010
3. Food packaging—Roles, materials, and environmental issues;Marsh;J. Food Sci.,2007
4. Wet strength resins in hygienic paper production;Hamm;Pap.-Z. Fur Die Erzeug. Von Holzst. Zellst. Pap. Und Pappe,1999
5. Lindström, T., Wågberg, L., and Larsson, T. (2005). 13th Fundamental Research Symposium, The Pulp and Paper Fundamental Research Society.