"EFFECT OF COMBINED USE OF CATIONIC AND ANIONIC DRY STRENGTH ADDITiVES ON PROPERTIES OF RECYCLED FIBRE (MIXED OFFICE WASTE)"

Abstract

Day by day the demand for raw material mainly woods is increasing which is not mel with the supply needed because of the amount of forest trees going down, therefore recycled fiber is the best alternate way to meet this problem with a solution. But the main problem with recycled fiber is their declining strength properties this study is based on the usage of dry strength additives to restore the strength properties of recycled fiber. Two oppositely charged dry strength additives namely cationic polyvenyamine and anionic polyvinyl amine had been used in combination to improve the strength properties of secondary fiber from mixed office waste. Cationic polyvinyl amine single handedly improves the strength properties but a saturation level in improvement is observed between .2-.4% of chemical usage. But when both cationic and anionic polyvinyl amine were used in combination it shows an improvement which is 2-3 times more then when only cationic dry strength additive was used. The main improvement was found in tensile and burst strength, tear strength nearly remains same. Optical properties also show an insignificant downfall. Substitution of cationic polyvinyl amine with the natural dry strength additive cationic starch gives satisfying results only up to a substitution of 20%. 1-lence the conclusion drawn says that usage of combined use of cationic and anionic dry strength additive do restore the lost strength of recycled fiber, and this improvement is found to be around 25-28%.