Fate and influence of western red cedar extractives in mechanical pulping

The nature of chromophores in high-extractives mechanical pulps: Western red cedar (Thuja plicata Donn) chemithermomechanical pulp (CTMP)

“…The excellent correlation in the Brought to you by | University of Georgia Libraries Authenticated Download Date | 6/1/15 11:25 PM IR carbonyl region between the bands for the CTMP pulp and for the western red cedar methanol extractives (Table 1) gives a clue as to the presence of a component in the pulp that is closely related to the extractives. These findings confirm our previous hypothesis that the source of the color in western red cedar mechanical pulp is an oligomer of lignan (Johansson et al 2000a). These findings confirm our previous hypothesis that the source of the color in western red cedar mechanical pulp is an oligomer of lignan (Johansson et al 2000a).…”

“…It is known that the lignans are almost completely extractable from western red cedar heartwood (Swan et al 1969;Johansson et al 2000a). Apparently, during mechanical pulping these lignans are modified and are no longer extractable by methanol and absorb intensely throughout the UV/visible region (Figure 1).…”

Characterization of the Polyphenolics Related to the Colour of Western Red Cedar (Thuja plicata Donn) Heartwood

“…They found that both the coloured extract from cedar heartwood and a reddish-brown polymer formed by mild acid treatment of plicatic acid, a western red cedar lignan, gave GC/MS peaks that were characteristic of plicatic acid. In our recent examination of the chemical changes in western red cedar heartwood during mechanical pulping (Johansson et al 1999), we found evidence using diffuse reflectance spectroscopy to suggest that the lignans were primarily responsible for the chromophores in the heartwood, while contrasting evidence using GC/MS, indicated that the colour resided in a lignin like material. In contrast, Hergert's (1992) spectroscopic investigation of the extractable heartwood suggested that the colour was primarily due to a lignin-lignan co-polymer, with the lignan present as a minor component.…”

Kinetics of Hydrogen Peroxide Brightening of Western Red Cedar (Thuja plicata Donn) CTMP

“…In an effort to develop procedures capable of efficiently brightening cedar mechanical pulp to high brightness levels we are conducting a fundamental investigation into the nature of the color in western red cedar mechanical pulps. [9][10][11] This article reports the results of our investigation into the peroxide brightening kinetics of western red cedar CTMP and the factors that limit its efficacy.…”