Mechanical pulping

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Objectives - The short term objective is to search for innovative ways to enhance the quality of mechanical fibre so that it can be used in high performance grades or new grades of paper products, while the long term objective is to raise mechanical fibre to its highest value so that it can provide new or enhanced benefits and reduce manufacturing costs. Research Programs and Scientific Approaches - 1.  Influence of shear and compressive forces on fibre separation and surface fibrillation:  A laboratory PFI mill can be modified to provide varying shear-to-compression ratios. Other conditions such as refining gap and pulp consistency can also be varied. Pulp characteristics such as freeness, tensile, burst, tear, light scattering, opacity, water retention value, fibre length distribution, fines, curl, kink, coarseness, cell wall thickness and flexibility will be determined. SEM and XPS studies will also be conducted. 2.  Oxidation of long fibres from TMP: The poor bonding capacity of long fibres of mechanical pulp can be remedied by oxidation using ozone and 4-acetamido-TEMP, generating acidic groups on fibre surface which is important for inter-fibre bonding. 3.  Cationization of TMP fibres: The negatively charged surface of long fibres of mechanical pulp can be cationized to yield better adhesion with the short fibres and fines, and with filler and retention agents. Cationization of fibre surface can be done using a cationizing agent called 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTMAC), which is commonly used to cationize starch.