Accessibility of fiber surface sites for polymeric additives determines dry and wet tensile strength of paper sheets

Abstract This contribution focuses on understanding of paper wet-strength properties, by taking a closer look at the spatial distribution wet-strengthening polymers inside cellulosic fiber network deposited under different treatment conditions using confocal laser scanning microscopy as in situ imaging tool. We compare behavior samples treated with photochemically cross-linkable copolymer an impregnation process employing three solvents, namely water, 2-propanol (IPA) and 1-butanol (BuOH), respectively. As these solvents swell fibers to quite extents, deposition polymer, on, or in-between varies strongly, is shown in-depth analysis microscopy. The difference accessibility distinct surface sites exclusively also between controls macroscopic tensile strength both dry wet conditions.