REPLACING SYNTHETIC WET-STRENGTH ADDITIVES WITH BIO-BASED ADDITIVES IN TEA BAGS

Abstract

Wet-strength additives are vital in maintaining the structural integrity of paper and paper-based products in wet conditions. Most wet-strength additives are synthetically produced and pose environmental and human health risks. Therefore, there is a growing interest in developing natural and environment-friendly wet-strength additives for paper. However, the unavoidable replacement of these harmful wet-strength additives with greener materials to achieve similar wet-strength without compromising product performance, with the added option of sustainability, is challenging. This review discusses up-to-date conventional synthetic, natural, and other wet-strength additives used in developing wet-strength in paper-based products. A detailed description of the additive’s reaction mechanisms and working principles for achieving the required wet-strength is also analyzed. Moreover, a detailed comparative literature review of the physio-chemical properties of these wet-strength additives is also discussed. In this work, fibers were modified and covered to dialdehyde by reaction with different moles of sodium meta periodate, depending on the % modification of fibers. Further, Epsilon Poly-l-lysine 9EPL) was added to the modified fibers and later utilized as a wet-strength additive to provide permanent wet-strength in the paper. The modified fibers form irreversible bonds with EPL, thus giving permanent wet-strength to the prepared hand sheets. Further, FTIR confirmed the formation of an irreversible imine bond between modified fibers and EPL. Also, FE-SEM analysis was conducted to study the surface morphology of modified paper containing EPL. Later, the Mechanical properties of the paper were tested, and data were analyzed. The wet-strength and wet-strength index of modified paper containing EPL increased. However, dry-strength and tearstrength values decreased, the decline was further controlled, and dry-strength and tear-strength values were maintained equivalent to neat paper by optimizing the time of reaction of fibers with sodium meta periodate and % concentration of fiber modification. At last, wet-strength along with dry-strength and tear-strength were maintained at 5 min reaction time.