Effects of cellulose micro/nanofibers as paper additives in kraft and kraft-NaBH₄pulps

This study examined the effects of various CMF/CNFs (microfibrillated and nanofibrillated celluloses) on the relevant properties of paper produced from kraft and kraft-NaBH4 pulps. Subsequent effects of pretreatments on the mechanical, drainage, optical and physical properties of papers obtained from both kraft and kraft-NaBH4 pulps were also studied. Enzymatic pretreatments were accomplished using Celluclast 1.5 L and Pulpzyme HC 2500 enzymes; 2,2,6,6-tetramethyl-l-piperidinyloxy (TEMPO), phthalimide-N-oxy (PINO) and periodate were utilized in chemical pretreatments. Results showed that the mechanical properties of paper for both kraft and kraft-NaBH4 pulps were improved with the addition of different types of CMF/CNF samples, whereas the sheet drainage was impaired. With 1.5% additions of various CMFs, the kraft pulp and the kraft-NaBH4 pulp displayed increases of 8.32-18.3% and 2.33-8.86% in tensile strength and 6.00-14.0% and 14.0-22.0% in degrees SR, respectively. Compared to other pretreated CMF/CNFs, periodate oxidized-CMF/CNFs significantly affected the properties of papers obtained from both kraft and kraft-NaBH4 pulps. Results also showed that the addition of various CMF/CNFs had a greater effect on the kraft-NaBH4 pulp than on the kraft pulp.