Swelling and press dewatering of microfibrillated cellulose
Kemian tekniikan korkeakoulu | Master's thesis
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Master's Programme in Chemical, Biochemical and Materials Engineering
65 + 9
AbstractMicrofibrillated cellulose (MFC) have been gaining improved attention due to its unique properties and vast application possibilities. However, its high aspect ratio and gel-like structure results in increased swelling capacity, causing the removal of water to be very challenging. Therefore, the present work focuses on the understanding of the chemical environment impact on the swelling behavior of mechanically produced MFC, as well as its press dewatering potential. Water retention value (WRV) results showed that MFC swelling can be minimized by increasing conductivity to values above 75 microS/cm or reducing pH for values below 5. Moreover, MFC with higher level of fibrillation was found to be at least 2 times more influenced by these parameters than MFC with lower level of fibrillation, besides exhibiting higher water withholding capacity, suggesting that the degree of MFC processing increases the sensibility of this material towards chemical environment modifications. In addition, centrifugal compression value (CCV) results showed a linear correlation with WRV, indicating that higher MFC swelling leads to worse press dewatering performance. These findings are very relevant for industrial applications since the optimization of water removal processes leads to new opportunities regarding MFC production and distribution in large scale.
Thesis advisorOgushi Romeiro Ramires, Heloisa
microfibrillated cellulose, MFC, swelling, dewatering