Study on application of cellulose nanofibril treated by electron beam irradiation to wet-end

Abstract

Because of the many advantages of CNFs, interest in them has been increasing dramatically. Many studies involving the application of CNFs have been reported in nanocomposites, but an insufficient number of studies have attempted to identify the applicability of CNFs in the papermaking process. The present study examined the effect of wet end application of CNFs on paper strength. Many types of CNFs were made from bleached kraft pulps by a combination of electron beam irradiation, refining, and subsequent grinding. Electron beam irradiation was selected as a new pretreatment to reduce the amount of electrical energy required, and its effect on the properties of the CNFs was also analyzed. The paper strengths of handsheets made by adding CNFs to the pulp slurry were also analyzed. Electron beam irradiation had no significant effect on the viscosity, particle size, or crystallinity of the CNFs. However, the CNFs made from softwood bleached kraft pulp (SwBKP) showed the highest viscosity. The strengths of handsheets containing all the CNFs were improved dramatically. The CNFs made from hardwood bleached kraft pulp (HwBKP), in particular, improved the paper strength over that of papers made from SwB-KP. The CNF treated by electron beam irradiation showed relatively higher overall paper strengths than those untreated by electron beam irradiation.