Dev.of a Process Raman Probe of Pulp as a Continuous Gauge of the Physical and Mechanical Properties of EndUse Product:A RealTime Spectrochemical Link from Fibre to Paper through Advanced Chemometrics

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Canadian northern bleached softwood kraft (NBSK) market pulps represent the worldwide benchmark for fibre strength, length, fineness, and uniformity. Better pulp quality control, especially its fibre strength, is important to maintain this superiority in the marketplace. Fibre strength depends mainly on intrinsic fibre properties such as the degree of cellulose crystallinity and chemical constituents such as lignin, hemicullose, and hexenuronic acid (HexA). These intrinsic properties also affect processing, such as digestibility and bleachability. In addition, the degree of fibre deformation incurred during pulping process also affects how the fibre delivers its strength in a network during sheet formation. All of these parameters have been shown to be important, however, aside from lignin, none can be easily measured in a timely manner for process control. The present research will prove principle on a novel Raman system, and systematic chemometric approach allowing for rapid spectral data acquisition and definitive spectrochemical analysis of wet pulp under harsh manufacturing conditions. Electro-optical instrumentation research will lead to backscattering sampling geometries and confocal parameters, coupled with express laser wavelength, power and resolution, all selected to maximize the information contained in signature spectral features. The instrument system will incorporate sophisticated chemometrics strategies, employing wavelet transform and template-guided genetic-algorithm feature selection with multivariate classification to extract maximum analytical information from raw Raman spectra. A program of analysis correlating spectrochemical observations with conventional characterization of fibre and end-use sheet properties will prove principle toward a comprehensive Raman gauge for the instantaneous determination of pulp quality vis-a-vis paper appearance and strength.