Lignin-Carbohydrate Complex (LCC) is believed to have significant effect on lignin removal in kraft pulping. However, direct and detailed evidences are very limited, especially for hardwoods (HW). In this project, variations between kraft pulping of different hardwood species will be correlated with the chemical structures of the hardwood LCCs using a few industrially important hardwood species (E. grandis, E. niten and E. globulus, maple, alder, aspen and acacia). LCC preparations will be isolated from original wood and kraft pulps and comprehensively characterized using high-resolution NMR and wet chemistry methods. Better understanding the mechanism of hardwood pulping will allow optimization of the technical process.
Variations between kraft pulping of different hardwood species will be correlated with the morphology of the hardwood using a number of industrially important hardwood species (E. urograndis, E. niten and E. globulus, maple, alder, sweet gum, red oak, aspen, cottonwood and acacia). The kinetics of wood chips delignification will be studied and the reaction rate constants determined. The effect of the wood morphology on pulping performance will be elucidated by comparing the reaction rate of sawdust (only chemistry effect) with the delignification rate of the corresponding chips (the effect of the chemistry and morphology). The microstructure of the hardwood will be studies using FQA method to determine the distribution in the fiber length, width, coarseness, percentage of fines and vessels. The variations in the hardwood microstructure will be correlated with the rate of delignification to evaluate the effect of the wood morphology on the pulping performance.
Fraser fir is important to North Carolina both ecologically and economically. It is a key component of the spruce-fir ecosystem found at the highest elevations of the Appalachian Mountains, including scenic areas along the Blue Ridge Parkway and in Great Smoky Mountains National Park. It is also a major component of the Christmas tree farming industry, which brings over $100 million annually to rural regions of the state. Fraser fir populations in North Carolina have been devastated by an introduced pest, the balsam woolly adelgid (BWA). Death of BWA-infested Fraser fir seems to be due to an over-zealous defense response by the tree, rather than any direct effect of insect feeding. Other fir species from Asia or Europe are either completely resistant to BWA, or tolerant of BWA feeding without the excessive defense response found in Fraser fir. This research will use modern tools of biological research to understand why BWA-infested Fraser firs die, and to look for ways to prevent fir death.