The hydromechanical peeling method was proposed for separation and analysis of the wood pulp fibers' surface (P � S1) and central (S2-S3) layers. As compared to the non-destructive ESCA and other spectroscopy methods, peeling of fiber walls provides authentic fractions of the surface layers up to 1 �m in thickness. It has been established that the chemical composition of fiber surface layers differs noticeably from the fiber wall average numbers. A higher content of non-cellulosic constituents is found, especially that of lignin. It has been also demonstrated that bleaching of separated fiber surface material does not yield the same brightness level as that of the fiber secondary wall due to the more complex chemical composition of the surface layers.It is possible to speed up and refurbish the peeling process and its monitoring by using present-day digital equipment for determination of fiber dimensions and shape, thus providing additional prospects for fruitful employment of the method. It is convenient to apply the hydromechanical peeling for obtaining fibers with a clearly exposed secondary wall S2layer. It is established that such fibers create stronger inter-fiber bonds as compared to the unpeeled ones. When investigating the impact of a treatment on the surface of fibers, secondary wall is more appropriate due to the clear pattern of the cellulose microfibrils and their orientation (MFA angle). For example, it is observed that cold plasma treatment generates a structure, which is similar to the �lamellar� orientation instead of the �fibrillar� configuration.The hydromechanical peeling is usually performed in a disintegrator. The experiments show that the use of sharp mixer blades, in contrast to dull blades, promotes the formation of fibers with micro- and nano-whiskers, which are partly separated and partly connected to the fibers.

Properties and composition of wood pulp fiber walls: Hydromechanical peeling revisited

245th National Meeting (2013)

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