Regulation of Cardboard Wet Strength by Biomodified Gluten Treatment
Synthetic binders are used in technology of paper and cardboard production in order to enhance final product strength in wet state. These substances are far from being harmless beings to humans and the environment. Therefore it is very important to find biologically safe substancee for wet-strengthening of paper and cardboard, for instance, biopolymers. The purpose of the research is the increasing of wet strength of cardboard by biomodified gluten treatment. The effect of biocatalytically treated gluten on the deformation properties of cardboard is shown in accordance with the purpose of the research. Wheat gluten was treated by enzymatic preparations: hydrolase, transferase and lipase. Amino acid L-cysteine was added to gluten for cardboard treatment. The use of biomodified gluten as a biopolymer allows obtaining biodegradable fibrous materials with the lowest energy costs from renewable sources. Practical significance of the research is determined by replacement of formaldehyde resins and/or synthesized polymers, which are used to enhance the strength of paper and cardboard in wet state, to biomodified plant polymers. The increase (in relation to the blank sample) of the strength properties of cardboard: impregnated with biomodified gluten (transglutaminase) showed elongation up to 19%, for length and width directions in dry and wet states; impregnated with lipopan showed elongation up to 28%, for length and width directions in wet state. The obtained results show the potential application of biocatalytically treated gluten for increasing the wet strength of cardboard. The obtained materials are biodegradable.