PAPER making! g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 11, Number 1, 2025
PAPER CHEMICALS “ Optimizing Mixed Waste Paper Properties Through Formamidine Sulfinic Acid Bleaching and Cationic Additive Treatments ”, Sima Sepahvand, Iman Akbarpour & Alireza Ashori, Journal of Polymers and the Environment , Vol.33, pp.29 – 50, 2025. This study investigated the synergistic effects of formamidine sulfinic acid (FAS) bleaching and cationic additives on mixed waste paper (MWP) quality. MWP was chemically deinked and bleached with hydrogen peroxide (H 2 O 2 ) or FAS at concentrations of 1 – 4%. Cationic starch and cationic polyacrylamide (CPAM) were applied as dry-strength additives at 1 – 3%. FAS bleaching at 4% dosage outperformed H 2 O 2 , improving brightness by 17% and reducing yellowness by 56%. CPAM showed superior performance in enhancing paper strength properties compared to cationic starch, with an optimal concentration of 2% for both additives. Surface charge analysis demonstrated effective fiber negative charge neutralization by both additives, with CPAM exhibiting higher efficiency. Field emission scanning electron microscopy (FESEM) confirmed significant improvements in fiber surface characteristics, particularly with 2% CPAM and 4% FAS combination. Water retention value decreased with additive application, potentially improving dewatering efficiency. Results indicate that combining FAS bleaching with optimized CPAM dosage can significantly enhance recycled paper quality, potentially narrowing the gap between recycled and virgin pulp properties. “Novel modifications of rosin emulsion formulations for Internal sizing of paper”, Eemil Åhman, Lappeenranta – Lahti University of Technology LUT, Master’s Thesis , 2025. In this master’s thesis different kinds of novel additives in rosin emulsion formulations were researched for internal sizing of paper. The research focuses on different stabilization mechanisms and modified rosins that could improve the sizing performance and strength of paper. The thesis was done as project work for Kemira Oyj, R&D department, Sizing & Performance team, in cooperation with a piloting plant of Kemira. Emulsion blends of fortified rosin with different modified rosins and stabilizing agents were formulated at the pilot plant. The chemical properties of the emulsions were tested, and paper hand sheets were formed at the research centre to evaluate the sizing performance of the emulsions. Performance of the sizing was evaluated with Cobb-absorbency test and the paper strength with tensile strength tester. The modified rosin blend emulsions had similar results as the reference samples as did the stabilizer trials. Hydrogenated and dimerized rosin blends resulted in slightly better sizing performance but losing in tensile strength of the paper. An unexpected increase in tensile strength of paper was found by replacing some cationic starch with a biopolymer particle stabilizer while keeping the sizing performance nearly the same. PAPERMAKING “ The impact of the milling process as a key factor in pulp and paper manufacturing ”, Dmitry Bolgov, Marina Savelyeva, Roman Marchenko & Margarita Litvinova, AIP Conf. Proc . 3268, 050025, 2025. In the pulp and paper manufacturing industry, the selection of a grinding process is a critical factor that influences not only the final product quality but also the operational efficiency and environmental sustainability of the manufacturing process. This research examines the impact of different grinding techniques, with a focus on conventional mechanical methods and novel knife-free techniques, on the characteristics of pulp and paper products. The findings indicate that knife-free milling methods enable the production of cellulose with comparable or superior properties compared to conventional methods, while enhancing the uniformity and tensile strength of fibers. The outcomes suggest that the choice of grinding method significantly influences the environmental footprint and economic feasibility of pulp and paper manufacture, contributing to a transition towards more innovative and energy-efficient technologies in the sector.
Technical Abstracts
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