The irradiation of pulp is of interest from different perspectives. Mainly it is required when a modification of cellulose is needed. Irradiation could bring many advantages, such as chemical savings and, therefore, cost savings and a reduction in environmental pollutants. In this account, pulp and dissociated celluloses were analyzed before and after irradiation by electron beaming. The focus of the analysis was the oxidation of hydroxyl groups to carbonyl and carboxyl groups in pulp and the degradation of cellulose causing a decrease in molar mass. For that purpose, the samples were labeled with a selective fluorescence marker and analyzed by gel permeation chromatography (GPC) coupled with multi-angle laser light scattering (MALLS), refractive index (RI), and fluorescence detectors. Degradation of the analyzed substrates was the predominant result of the irradiation; however, in the microcrystalline samples, oxidized cellulose functionalities were introduced along the cellulose chain, making this substrate suitable for further chemical modification.

Fibers resulting from pulping of wood are negatively charged by nature. This charge might be reversed by chemical modification for different applications. In this study, different options to determine the degree of substitution (DS) with cationic groups introduced using 2,3-epoxypropyltrimethylammonium chloride, a common cationization reagent, are compared. Classical analytical methods for this purpose include elemental analysis, which is unspecific, and titration, which is sensitive toward impurities and highly elaborate. These are complemented by fast and robust approaches based on infrared spectroscopy or thermogravimetric analysis. The absorption increase at 1480 cm⁻¹ is specific for the introduced R-NMe₃ and linearly correlated with the DS. For bleached Kraft pulps, cationization splits the thermal degradation of cellulose in two phases, their ratio being roughly proportional to the DS. Both methods require virtually no sample preparation. Infrared spectroscopy is particularly easy to apply and allows a quantification of pulp cationization in short time.