| Summary: | This study was aimed to compare pulp properties of Pinus pinea heartwood and sapwood pulp obtained from modified soda method and to investigate effects of potassium borohydride (KBH4) used as a protective agent in cooking processes. Eight different cooking experiments were applied to the heartwood and sapwood samples by changing KBH4 ratio. The effects of KBH4 on some chemical, physical and optical properties of pulps obtained from cooking processes were determined. Due to high content of soluble extraction of heartwood, yield of heartwood pulp was approximately 24% lower than that of sapwood pulp. Using KBH4 in pulping processes increased sapwood pulp yield, while it has a decreasing impact on heartwood pulp yield. Kappa number and viscosity values of sapwood pulps were better than those of heartwood pulps. With addition of KBH4 to liquor there was increased kappa numbers of sapwood pulp in contrast to heartwood. In generally, physical properties of sapwood pulp are better than that of heartwood pulp. But, there are no significant difference in optical properties between heartwood and sapwood pulp. With no regard to the type of pulps used, the pulp optical properties were improved by using KBH4 in pulping processes.
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