Evaluation of electron beam irradiation as new pretreatment for cellulose nanofibril production

Abstract

Many studies have reported that cellulose nanofibrils (CNFs) show high potential for use in many industries, but this material has been considered too costly for commercialization. An effective treatment is therefore needed to reduce the production costs of CNFs. This study describes the use of electron beam irradiation as a new pretreatment for the manufacture of CNFs and the effectiveness of electron beam irradiation in the refining process, which is a part of CNF production. Bleached kraft pulps were irradiated by an electron beam and subsequently refined, followed by measurement of the freeness and fiber properties. The strengths of treated pulps were identified by preparing handsheets and analyzing their strengths. Increases in the irradiation dose of the electron beam and in the beating time decreased the freeness and fiber length of the pulps. The images acquired with an optical microscope demonstrated fibrillation of pulps. The handsheets made from the pulps irradiated by the electron beam and beaten showed lower strengths because of the reduction in the degree of polymerization and crystallinity. Therefore, electron beam irradiation is concluded to reduce the amount of electric energy needed in the manufacturing process of CNFs, but the irradiation dose of electron beam must be controlled to avoid severe deterioration of the fiber strength.